National Library of Energy BETA

Sample records for ray mass attenuation

  1. Sparse signal reconstruction from polychromatic X-ray CT measurements via mass attenuation discretization

    SciTech Connect (OSTI)

    Gu, Renliang; Dogandži?, Aleksandar [Iowa State University, Center for Nondestructive Evaluation, 1915 Scholl Road, Ames, IA 50011 (United States)

    2014-02-18

    We propose a method for reconstructing sparse images from polychromatic x-ray computed tomography (ct) measurements via mass attenuation coefficient discretization. The material of the inspected object and the incident spectrum are assumed to be unknown. We rewrite the Lambert-Beer’s law in terms of integral expressions of mass attenuation and discretize the resulting integrals. We then present a penalized constrained least-squares optimization approach for reconstructing the underlying object from log-domain measurements, where an active set approach is employed to estimate incident energy density parameters and the nonnegativity and sparsity of the image density map are imposed using negative-energy and smooth ?{sub 1}-norm penalty terms. We propose a two-step scheme for refining the mass attenuation discretization grid by using higher sampling rate over the range with higher photon energy, and eliminating the discretization points that have little effect on accuracy of the forward projection model. This refinement allows us to successfully handle the characteristic lines (Dirac impulses) in the incident energy density spectrum. We compare the proposed method with the standard filtered backprojection, which ignores the polychromatic nature of the measurements and sparsity of the image density map. Numerical simulations using both realistic simulated and real x-ray ct data are presented.

  2. Measurement of the x-ray mass attenuation coefficient and determination of the imaginary component of the atomic form factor of tin over the energy range of 29-60 keV

    SciTech Connect (OSTI)

    Jonge, Martin D. de; Tran, Chanh Q.; Chantler, Christopher T.; Barnea, Zwi; Dhal, Bipin B.; Paterson, David; Kanter, Elliot P.; Southworth, Stephen H.; Young, Linda; Beno, Mark A.; Linton, Jennifer A.; Jennings, Guy [X-Ray Operations and Research, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); School of Physics, University of Melbourne, Victoria 3010 (Australia); Australian Synchrotron Project, Major Projects Victoria, 800 Blackburn Road, Clayton, Victoria 3168 (Australia); Chemistry Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); BESSRC-CAT, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

    2007-03-15

    We use the x-ray extended-range technique (XERT) [C. T. Chantler et al., Phys. Rev. A 64, 062506 (2001)] to measure the mass attenuation coefficients of tin in the x-ray energy range of 29-60 keV to 0.04-3 % accuracy, and typically in the range 0.1-0.2 %. Measurements made over an extended range of the measurement parameter space are critically examined to identify, quantify, and correct a number of potential experimental systematic errors. These results represent the most extensive experimental data set for tin and include absolute mass attenuation coefficients in the regions of x-ray absorption fine structure, extended x-ray absorption fine structure, and x-ray absorption near-edge structure. The imaginary component of the atomic form factor f{sub 2} is derived from the photoelectric absorption after subtracting calculated Rayleigh and Compton scattering cross sections from the total attenuation. Comparison of the result with tabulations of calculated photoelectric absorption coefficients indicates that differences of 1-2 % persist between calculated and observed values.

  3. The Dust Attenuation Curve versus Stellar Mass for Emission Line Galaxies at z ~ 2

    E-Print Network [OSTI]

    Zeimann, Gregory R; Gronwall, Caryl; Bridge, Joanna; Brooks, Hunter; Fox, Derek; Gawiser, Eric; Gebhardt, Henry; Hagen, Alex; Schneider, Donald P; Trump, Jonathan R

    2015-01-01

    We derive the mean wavelength dependence of stellar attenuation in a sample of 239 high redshift (1.90 & Conroy, who found that the wavelength dependence of attenuation varies with galaxy spectral type. However, we find no evidence of an extinction "bump" at 2175 A in any of the three stellar mass bins, or in the sample as a whole. We quantify the relation between the attenuation curve and stellar mass and discuss its implications.

  4. Dual energy CT-based characterization of x-ray attenuation properties of breast equivalent material plates

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Dual energy CT-based characterization of x-ray attenuation properties of breast equivalent material of the same nominal breast density equivalence (+ 1.5 HU). In addition, dual energy CT provided mono equivalent material, breast density, attenuation properties, linear attenuation coefficients, dual energy CT

  5. Imaging method based on attenuation, refraction and ultra-small-angle-scattering of x-rays

    DOE Patents [OSTI]

    Wernick, Miles N.; Chapman, Leroy Dean; Oltulu, Oral; Zhong, Zhong

    2005-09-20

    A method for detecting an image of an object by measuring the intensity at a plurality of positions of a transmitted beam of x-ray radiation emitted from the object as a function of angle within the transmitted beam. The intensity measurements of the transmitted beam are obtained by a crystal analyzer positioned at a plurality of angular positions. The plurality of intensity measurements are used to determine the angular intensity spectrum of the transmitted beam. One or more parameters, such as an attenuation property, a refraction property and a scatter property, can be obtained from the angular intensity spectrum and used to display an image of the object.

  6. Attenuation of super-soft X-ray sources by circumstellar material

    E-Print Network [OSTI]

    Nielsen, Mikkel

    2015-01-01

    Recent studies have suggested the possibility of significantly obscuring super-soft X-ray sources in relatively modest amounts of local matter lost from the binaries themselves. If correct, then this would have explained the paucity of observed super-soft X-ray sources and would have significance for the search for single-degenerate type Ia supernova progenitors. We point out that earlier studies of circumbinary obscuration ignored photo-ionisations of the gas by the emission from the super-soft X-ray source. We revisit the problem using a full, self-consistent calculation of the ionisation state of the circumbinary material photo-ionised by the radiation of the central source. Our results show that the circumstellar mass-loss rates required for obcuration of super-soft X-ray sources is about an order of magnitude larger than those reported in earlier studies, for comparable model parameters. While this does not entrirely rule out the possibility of circumstellar material obscuring super-soft X-ray sources, i...

  7. A field comparison of Fresnel zone and ray-based GPR attenuation-difference tomography for time-lapse imaging of

    E-Print Network [OSTI]

    Barrash, Warren

    A field comparison of Fresnel zone and ray-based GPR attenuation-difference tomography for time the medium. These sensitivities occupy the first Fresnel zone, account for the finite frequency nature

  8. Flat panel X-ray detector with reduced internal scattering for improved attenuation accuracy and dynamic range

    DOE Patents [OSTI]

    Smith, Peter D. (Santa Fe, NM); Claytor, Thomas N. (White Rock, NM); Berry, Phillip C. (Albuquerque, NM); Hills, Charles R. (Los Alamos, NM)

    2010-10-12

    An x-ray detector is disclosed that has had all unnecessary material removed from the x-ray beam path, and all of the remaining material in the beam path made as light and as low in atomic number as possible. The resulting detector is essentially transparent to x-rays and, thus, has greatly reduced internal scatter. The result of this is that x-ray attenuation data measured for the object under examination are much more accurate and have an increased dynamic range. The benefits of this improvement are that beam hardening corrections can be made accurately, that computed tomography reconstructions can be used for quantitative determination of material properties including density and atomic number, and that lower exposures may be possible as a result of the increased dynamic range.

  9. THE EXTRAGALACTIC BACKGROUND LIGHT FROM THE MEASUREMENTS OF THE ATTENUATION OF HIGH-ENERGY GAMMA-RAY SPECTRUM

    SciTech Connect (OSTI)

    Gong Yan; Cooray, Asantha [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)

    2013-07-20

    The attenuation of high-energy gamma-ray spectrum due to the electron-positron pair production against the extragalactic background light (EBL) provides an indirect method to measure the EBL of the universe. We use the measurements of the absorption features of the gamma-rays from blazars as seen by the Fermi Gamma-ray Space Telescope to explore the EBL flux density and constrain the EBL spectrum, star formation rate density (SFRD), and photon escape fraction from galaxies out to z = 6. Our results are basically consistent with the existing determinations of the quantities. We find a larger photon escape fraction at high redshifts, especially at z = 3, compared to the result from recent Ly{alpha} measurements. Our SFRD result is consistent with the data from both gamma-ray burst and ultraviolet (UV) observations in the 1{sigma} level. However, the average SFRD we obtain at z {approx}> 3 matches the gamma-ray data better than the UV data. Thus our SFRD result at z {approx}> 6 favors the fact that star formation alone is sufficiently high enough to reionize the universe.

  10. Single-shot Zeff dense plasma diagnostic through simultaneous refraction and attenuation measurements with a Talbot–Lau x-ray moiré deflectometer

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Valdivia, M. P.; Stutman, D.; Finkenthal, M.

    2015-03-23

    The Talbot–Lau x-ray moiré deflectometer is a powerful plasma diagnostic capable of delivering simultaneous refraction and attenuation information through the accurate detection of x-ray phase shift and intensity. The diagnostic can provide the index of refraction n = 1 - ? + i? of an object (dense plasma, for example) placed in the x-ray beam by independently measuring both ? and ?, which are directly related to the electron density ne and the attenuation coefficient ?, respectively. Since ? and ? depend on the effective atomic number Zeff, a map can be obtained from the ratio between phase and absorptionmore »images acquired in a single shot. The Talbot–Lau x-ray moiré deflectometer and its corresponding data acquisition and processing are briefly described to illustrate how the above is achieved; Zeff values of test objects within the 4–12 range were obtained experimentally through simultaneous refraction and attenuation measurements. We show that Zeff mapping of objects does not require previous knowledge of sample length or shape. The determination of Zeff from refraction and attenuation measurements with Moiré deflectometry could be of high interest to various domains of HED research, such as shocked materials and ICF experiments, as well as material science and NDT.« less

  11. Determination of x-ray spectra from Al attenuation data by imposing a priori physical features of the spectrum: Theory and experimental validation

    SciTech Connect (OSTI)

    Delgado, Victor [Departamento de Radiologia, Universidad Complutense 28040 Madrid (Spain)

    2009-01-15

    The determination of the spectral distribution of an x-ray beam from attenuation measurements in a narrow beam is an ill-conditioned problem that has aroused great interest since it was first proposed by Silberstein in 1932. In this work, the explicit reconstruction of the spectral distribution directly from the attenuation curve, without differentiating it, is carried out by a maximum likelihood method that allows one to impose a priori physical features of an x-ray spectral distribution, such as the positiveness of the solution, the boundness of its support, and the position and shape of the spikes and edges associated with the characteristic radiation. The numerical simulations made and the experimental validation of the proposed method have shown that it is possible to reconstruct x-ray spectra that, having a realistic shape, accurately fit the attenuation curve and predict the energy fluence. Nevertheless, the reconstruction of spectra including the K x rays of W is less accurate than the reconstruction of spectra including L x rays of W or K x rays of Mo, even when a priori information about the position and shape of the spikes and edges associated with the characteristic radiation is used.

  12. X-ray Spectroscopy of O Supergiant Winds: Shock Physics, Clumping, and Mass-Loss Rates

    E-Print Network [OSTI]

    Cohen, David

    X-ray Spectroscopy of O Supergiant Winds: Shock Physics, Clumping, and Mass-Loss Rates David Cohen-ray emission: wind shocks 1. X-ray constraints on the shocked wind plasma 2. X-ray absorption as a mass. Adiabatic shocks Open questions: very dense winds (WR stars); low density winds (B stars); magnetic OB stars

  13. Attenuation of external Bremsstrahlung in metallic absorbers

    SciTech Connect (OSTI)

    Dhaliwal, A.S.; Powar, M.S.; Singh, M. (Punjabi Univ., Physics Dept., Patiala 147002 (IN))

    1990-12-01

    In this paper attenuation of bremsstrahlung from {sup 147}Pm and {sup 170}Tm beta emitters has been studied in aluminum, copper, tin, and lead metallic absorbers. Bremsstrahlung spectra and mass attenuation coefficients for monoenergetic gamma rays are used to calculate theoretical attenuation curves. Magnetic deflection and beta stopping techniques are used to measure the integral bremsstrahlung intensities above 30 keV in different target thicknesses. Comparison of measured and calculated attenuation curves shows a good agreement for various absorbers, thus providing a test of this technique, which may be useful in understanding bremsstrahlung intensity buildup and in the design of optimum shielding for bremsstrahlung sources. It is found that the absorption of bremsstrahlung in metallic absorbers does not obey an exponential law and that absorbers act as energy filters.

  14. X-ray Spectroscopy of Massive Star Winds: Shocks, Mass-Loss Rates, and Clumping

    E-Print Network [OSTI]

    Cohen, David

    X-ray Spectroscopy of Massive Star Winds: Shocks, Mass-Loss Rates, and Clumping David Cohen X-rays A. wind-shock physics B. wind absorption: wind mass-loss rate C. with H-alpha: wind clumping Chandra resolved X-ray line profile spectroscopy of O star winds #12;Prior to 2000: only low-resolution X

  15. Did a gamma-ray burst initiate the late Ordovician mass extinction?

    E-Print Network [OSTI]

    Jackman, Charles H.

    Did a gamma-ray burst initiate the late Ordovician mass extinction? A.L. Melott1 , B.S. Lieberman2 Abstract: Gamma-ray bursts (GRBs) produce a flux of radiation detectable across the observable Universe words: Population and evolution, mass extinction, gamma-ray burst, Ordovician, ultraviolet ozone

  16. Probing Long Gamma Ray Bursts progenitor mass by Gravitational Waves

    E-Print Network [OSTI]

    De Laurentis, Mariafelicia; Dainotti, Maria Giovanna; Milano, Leopoldo

    2015-01-01

    In this work we present a procedure to infer the mass of progenitors and remnants of Gamma Ray Bursts (GRB), starting from the observed energy $E_{iso}^{GRB}$ emitted isotropically and considering the associated emission of Gravitational Waves (GW) $ E_{iso}^{GW}$ in the different phases. We assume that the GW energy of the progenitor $E_{PROG}^{GW}$ is emitted partially during a star collapse, and the residual energy is related to the GW energy emitted by the remnant. We take a sample of $237$ Long GRB, and use an hybrid Montecarlo procedure to explore, for each of them, a region of possible solutions of $ E_{iso}^{GW}$ as a function of the masses, radii, oblateness, rotation frequencies of progenitor and remnant and the fraction of energy $k$ emitted as GW by the GRB. We discriminate between a Neutron Star (NS) or Black Hole (BH) for the remnant and obtain interesting values for the GW emitted by the remnant NS or BH, for the conversion factor $k$ of and for the masses and radii of GRB progenitor stars. We ...

  17. Potential Gamma-ray Emissions from Low-Mass X-ray Binary Jets

    E-Print Network [OSTI]

    Zhang, Jian-Fu; Liu, Tong; Xue, Li; Lu, Ju-Fu

    2015-01-01

    By proposing a pure leptonic radiation model, we study the potential gamma-ray emissions from jets of the low-mass X-ray binaries. In this model, the relativistic electrons that are accelerated in the jets are responsible for radiative outputs. Nevertheless, dynamics of jets are dominated by the magnetic and proton-matter kinetic energies. The model involves all kinds of related radiative processes and considers the evolution of relativistic electrons along the jet by numerically solving the kinetic equation. Numerical results show that the spectral energy distributions can extend up to TeV bands, in which synchrotron radiation and synchrotron self-Compton scattering are dominant components. As an example, we apply the model to the low-mass X-ray binary GX 339-4. The results can not only reproduce the currently available observations from GX 339-4, but also predict detectable radiation at GeV and TeV bands by Fermi and CTA telescopes. The future observations with Fermi and CTA can be used to test our model, w...

  18. Investigation of photon attenuation coefficient of some building materials used in Turkey

    SciTech Connect (OSTI)

    Dogan, B.; Altinsoy, N.

    2015-03-30

    In this study, some building materials regularly used in Turkey, such as concrete, gas concrete, pumice and brick have been investigated in terms of mass attenuation coefficient at different gamma-ray energies. Measurements were carried out by gamma spectrometry containing NaI(Tl) detector. Narrow beam gamma-ray transmission geometry was used for the attenuation measurements. The results are in good agreement with the theoretical calculation of XCOM code.

  19. Enhancing the quality of radiographic images acquired with point-like gamma-ray sources through correction of the beam divergence and attenuation

    SciTech Connect (OSTI)

    Silvani, M. I.; Almeida, G. L.; Lopes, R. T.

    2014-11-11

    Radiographic images acquired with point-like gamma-ray sources exhibit a desirable low penumbra effects specially when positioned far away from the set object-detector. Such an arrangement frequently is not affordable due to the limited flux provided by a distant source. A closer source, however, has two main drawbacks, namely the degradation of the spatial resolution - as actual sources are only approximately punctual - and the non-homogeneity of the beam hitting the detector, which creates a false attenuation map of the object being inspected. This non-homogeneity is caused by the beam divergence itself and by the different thicknesses traversed the beam even if the object were an homogeneous flat plate. In this work, radiographic images of objects with different geometries, such as flat plates and pipes have undergone a correction of beam divergence and attenuation addressing the experimental verification of the capability and soundness of an algorithm formerly developed to generate and process synthetic images. The impact of other parameters, including source-detector gap, attenuation coefficient, ratio defective-to-main hull thickness and counting statistics have been assessed for specifically tailored test-objects aiming at the evaluation of the ability of the proposed method to deal with different boundary conditions. All experiments have been carried out with an X-ray sensitive Imaging Plate and reactor-produced {sup 198}Au and {sup 165}Dy sources. The results have been compared with other technique showing a better capability to correct the attenuation map of inspected objects unveiling their inner structure otherwise concealed by the poor contrast caused by the beam divergence and attenuation, in particular for those regions far apart from the vertical of the source.

  20. The accretion process in neutron-star low-mass X-ray binaries

    E-Print Network [OSTI]

    Lin, Dacheng

    2009-01-01

    There had been long-standing fundamental problems in the spectral studies of accreting neutron stars (NSs) in low-mass X-ray binaries involving the X-ray spectral decomposition, the relations between subtypes (mainly atoll ...

  1. X-ray Spectral Measurements of the Most Massive Stars: Stellar Wind Mass-Loss Rates and Shock Physics

    E-Print Network [OSTI]

    Cohen, David

    X-ray Spectral Measurements of the Most Massive Stars: Stellar Wind Mass-Loss Rates and Shock, and their winds (the site of X-ray production). From the basic question of how the X-rays are produced, I have branched out to questions of wind structure and wind mass-loss rates that the X-ray observations can

  2. Control algorithms for dynamic attenuators

    SciTech Connect (OSTI)

    Hsieh, Scott S., E-mail: sshsieh@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)] [Department of Radiology, Stanford University, Stanford California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-15

    Purpose: The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. Methods: The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not requirea priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. Results: The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current modulation) without increasing peak variance. The 15-element piecewise-linear dynamic attenuator reduces dose by an average of 42%, and the perfect attenuator reduces dose by an average of 50%. Improvements in peak variance are several times larger than improvements in mean variance. Heuristic control eliminates the need for a prescan. For the piecewise-linear attenuator, the cost of heuristic control is an increase in dose of 9%. The proposed iterated WMV minimization produces results that are within a few percent of the true solution. Conclusions: Dynamic attenuators show potential for significant dose reduction. A wide class of dynamic attenuators can be accurately controlled using the described methods.

  3. X-ray spectroscopy of neutron star low-mass X-ray binaries

    E-Print Network [OSTI]

    Krauss, Miriam Ilana

    2007-01-01

    In this thesis, I present work spanning a variety of topics relating to neutron star lowmass X-ray binaries (LMXBs) and utilize spectral information from X-ray observations to further our understanding of these sources. ...

  4. Wormholes, Gamma Ray Bursts and the Amount of Negative Mass in the Universe

    E-Print Network [OSTI]

    Diego F. Torres; Gustavo E. Romero; Luis A. Anchordoqui

    1998-05-19

    In this essay, we assume that negative mass objects can exist in the extragalactic space and analyze the consequences of their microlensing on light from distant Active Galactic Nuclei. We find that such events have very similar features to some observed Gamma Ray Bursts and use recent satellite data to set an upper bound to the amount of negative mass in the universe.

  5. Effective atomic numbers of blue topaz at different gamma-rays energies obtained from Compton scattering technique

    SciTech Connect (OSTI)

    Tuschareon, S. Limkitjaroenporn, P. Kaewkhao, J.

    2014-03-24

    Topaz occurs in a wide range of colors, including yellow, orange, brown, pink-to-violet and blue. All of these color differences are due to color centers. In order to improve the color of natural colorless topaz, the most commonly used is irradiated with x- or gamma-rays, indicated that attenuation parameters is important to enhancements by irradiation. In this work, the mass attenuation coefficients of blue topaz were measured at the different energy of ?-rays using the Compton scattering technique. The results show that, the experimental values of mass attenuation coefficient are in good agreement with the theoretical values. The mass attenuation coefficients increase with the decrease in gamma rays energies. This may be attributed to the higher photon interaction probability of blue topaz at lower energy. This result is a first report of mass attenuation coefficient of blue topaz at different gamma rays energies.

  6. INTEGRAL and New Classes of High-Mass X-ray Binaries

    E-Print Network [OSTI]

    Christoph Winkler

    2007-12-04

    The gamma-ray observatory INTEGRAL, launched in October 2002, produces a wealth of discoveries and new results on compact high energy Galactic objects, nuclear gamma-ray line emission, diffuse line and continuum emission, cosmic background radiation, AGN and high energy transients. Two important serendipitous discoveries made by the INTEGRAL mission are new classes of X-ray binaries, namely the highly-obscured high-mass X-ray binaries, and the super-giant fast transients. In this paper I will review the current status of these discoveries.

  7. ON THE DISCREPANCY BETWEEN THEORETICAL AND X-RAY CONCENTRATION-MASS RELATIONS FOR GALAXY CLUSTERS

    SciTech Connect (OSTI)

    Rasia, E. [Department of Physics, University of Michigan, 450 Church Street, Ann Arbor, MI 48109 (United States); Borgani, S. [Dipartimento di Fisica dell' Università di Trieste, Sezione di Astronomia, via Tiepolo 11, I-34131 Trieste (Italy); Ettori, S.; Meneghetti, M. [INAF, Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127, Bologna (Italy); Mazzotta, P. [Dipartimento di Fisica, Università di Roma Tor Vergata, via della Ricerca Scientifica, I-00133, Roma (Italy)

    2013-10-10

    In the past 15 years, the concentration-mass relation has been investigated diffusely in theoretical studies. On the other hand, only recently has this relation been derived from X-ray observations. When that happened, the results caused a certain level of concern: the X-ray normalizations and slopes were found significantly dissimilar from those predicted by theory. We analyzed 52 galaxy clusters and groups, simulated with different descriptions of the physical processes that affect the baryonic component, with the purpose of determining whether these discrepancies are real or induced by biases in the computation of the concentration parameter or in the determination of the selection function of the cluster sample for which the analysis is carried out. In particular, we investigate how the simulated concentration-mass relation depends (1) on the radial range used to derive the concentration; (2) on the presence of baryons in the simulations, and on the effect of star formation and feedback from supernovae and active galactic nuclei (AGNs). Finally, we evaluate (3) how the results differ when adopting an X-ray approach for the analysis and (4) how the selection function based on X-ray luminosity can impact the results. All effects studied go in the direction of alleviating the discrepancy between observations and simulations, although with different significance: while the choice of the radial range to fit the profiles and the inclusion of the baryonic component play only a minor role, the X-ray approach to reconstruct the mass profiles and the selection of the cluster sample have a strong impact on the resulting concentration-mass relation. Extending the fit to the most central regions or reducing the fitting radius from the virial boundary to the typical X-ray external radius causes an increase of the normalization in radiative simulations by 5%-10%. In the second case, we measure a slope that is up to twice steeper than that derived by using the typical theoretical radial range. Radiative simulations including only supernova feedback produce 30% higher concentrations than the dark matter case. Such a difference is largely reduced when including the effect of AGN feedback. The concentration-mass relation derived from the X-ray synthetic catalog is significantly steeper due to the combination of several different effects, such as environment, dynamical state and dynamical history of the clusters, bias in mass and temperature measurements, and their dependence on the radius and on the mass of the system. Finally, selecting clusters according to their X-ray luminosity produces a net increase in both normalization and slope of the relation, since at fixed mass, the most luminous clusters are also the most concentrated.

  8. A Lack of Radio Emission from Neutron Star Low Mass X-ray Binaries

    E-Print Network [OSTI]

    Michael P. Muno; Tomaso Belloni; Vivek Dhawan; Edward H. Morgan; Ronald A. Remillard; Michael P. Rupen

    2004-11-11

    We report strict upper limits to the radio luminosities of three neutron star low-mass X-ray binaries obtained with the Very Large Array while they were in hard X-ray states as observed with the Rossi X-ray Timing Explorer: 1E 1724-307, 4U 1812-12, and SLX 1735-269. We compare these upper limits to the radio luminosities of several black hole binaries in very similar hard states, and find that the neutron star systems are as faint as or fainter than all of the black hole candidates. The differences in luminosities can partly be attributed to the lower masses of the neutron star systems, which on theoretical and observational grounds are expected to decrease the radio luminosities as M^0.8. However, there still remains a factor of 30 scatter in the radio luminosities of black hole and neutron star X-ray binaries, particularly at X-ray luminosities of a few percent Eddington. We find no obvious differences in the X-ray timing and spectral properties that can be correlated with the radio luminosity. We discuss the implications of these results on current models for the relationship between accretion and jets.

  9. The Long Term Stability of Oscillations During Thermonuclear X-ray Bursts: Constraining the Binary X-ray Mass Function

    E-Print Network [OSTI]

    Tod E. Strohmayer; William Zhang; Jean H. Swank; Iosif Lapidus

    1998-06-18

    We report on the long term stability of the millisecond oscillations observed with the Rossi X-ray Timing Explorer (RXTE) during thermonuclear X-ray bursts from the low mass X-ray binaries (LMXB) 4U 1728-34 and 4U 1636-53. We show that bursts from 4U 1728-34 spanning more than 1.5 years have observed asymptotic oscillation periods which are within 0.2 microsec. of each other, well within the magnitude which could be produced by the orbital motion of the neutron star in a typical LMXB. This stability implies a timescale to change the oscillation period of > 23,000 years, suggesting a highly stable process such as stellar rotation as the oscillation mechanism. We show that period offsets in three distinct bursts from 4U 1636-53 can be plausibly interpreted as due to orbital motion of the neutron star in this 3.8 hour binary system. We discuss the constraints on the mass function which can in principle be derived using this technique.

  10. An Upper Bound on Neutron Star Masses from Models of Short Gamma-ray Bursts

    E-Print Network [OSTI]

    Lawrence, Scott; Bedaque, Paulo F; Miller, M Coleman

    2015-01-01

    The discovery of two neutron stars with gravitational masses $\\approx 2~M_\\odot$ has placed a strong lower limit on the maximum mass of a slowly rotating neutron star, and with it a strong constraint on the properties of cold matter beyond nuclear density. Current upper mass limits are much looser. Here we note that, if most short gamma-ray bursts are produced by the coalescence of two neutron stars, and if the merger remnant collapses quickly, then the upper mass limit is constrained tightly. We find that if the rotation of the merger remnant is limited only by mass-shedding (which seems plausible based on current numerical studies), then the maximum gravitational mass of a slowly rotating neutron star is between $\\approx 2~M_\\odot$ and $\\approx 2.2~M_\\odot$ if the masses of neutron stars that coalesce to produce gamma-ray bursts are in the range seen in Galactic double neutron star systems. These limits are increased by $\\sim 4$% if the rotation is slowed by $\\sim 30$%, and by $\\sim 15$% if the merger remna...

  11. The spectra of accretion discs in low-mass X-ray binaries

    E-Print Network [OSTI]

    R. R. Ross; A. C. Fabian

    1995-11-14

    We present self-consistent models for the radiative transfer in Shakura-Sunyaev accretion discs in bright low-mass X-ray binaries (LMXB). Our calculations include the full effects of incoherent Compton scattering and the vertical temperature structure within the disc, as well as the effects of Doppler blurring and gravitational redshift. We find that the observed X-ray spectra are well fit by exponentially cutoff power-law models. The difference between the observed total spectrum and our calculated disc spectrum should reveal the spectrum of the disc/neutron star boundary layer and other emitting regions considered to be present in LMXB.

  12. Accretion Disk Boundary Layers Around Neutron Stars: X-ray Production in Low-Mass X-ray Binaries

    E-Print Network [OSTI]

    Robert Popham; Rashid Sunyaev

    2000-04-03

    We present solutions for the structure of the boundary layer where the accretion disk meets the neutron star, which is expected to be the dominant source of high-energy radiation in low-mass X-ray binaries which contain weakly magnetized accreting neutron stars. We find that the main portion of the boundary layer gas is hot (> ~10^8 K), low in density, radially and vertically extended, and optically thick to scattering but optically thin to absorption. It will produce large X-ray luminosity by Comptonization. Energy is transported inward by viscosity, concentrating the energy dissipation in the dense, optically thick zone close to the stellar surface. We explore the dependence of the boundary layer structure on the mass accretion rate, the rotation rate of the star, the alpha viscosity parameter and the viscosity prescription. Radiation pressure is the dominant source of pressure in the boundary layer; the flux is close to the Eddington limiting flux even for luminosities well below (~0.01 times) L(Edd). At luminosities near L(Edd), the boundary layer expands radially, and has a radial extent larger than one stellar radius. Based on the temperatures and optical depths which characterize the boundary layer, we expect that Comptonization will produce a power-law spectrum at low source luminosities. At high luminosities, a Planckian spectrum will be produced in the dense region where most of the energy is released, and modified by Comptonization as the radiation propagates outward.

  13. The prospects for constraining dark energy with future X-ray cluster gas mass fraction measurements

    E-Print Network [OSTI]

    David Rapetti; Steven W. Allen; Adam Mantz

    2008-06-25

    We examine the ability of a future X-ray observatory to constrain dark energy via measurements of the cluster X-ray gas mass fraction, fgas. We find that fgas measurements for a sample of ~500 hot, X-ray bright, dynamically relaxed clusters, to a precision of ~5 per cent, can be used to constrain dark energy with a Dark Energy Task Force (DETF) figure of merit of 15-40, with the possibility of boosting these values by 40 per cent or more by optimizing the redshift distribution of target clusters. Such constraints are comparable to those predicted by the DETF for other leading, planned dark energy experiments. A future fgas experiment will be preceded by a large X-ray or SZ survey that will find hot, X-ray luminous clusters out to high redshifts. Short `snapshot' observations with the new X-ray observatory should then be able to identify a sample of ~500 suitably relaxed systems. The redshift, temperature and X-ray luminosity range of interest has already been partially probed by existing X-ray cluster surveys which allow reasonable estimates of the fraction of clusters that will be suitably relaxed for fgas work. Our analysis uses a Markov Chain Monte Carlo method which fully captures the relevant degeneracies between parameters and facilitates the incorporation of priors and systematic uncertainties in the analysis. We explore the effects of such uncertainties for scenarios ranging from optimistic to pessimistic. We conclude that the fgas experiment will provide tight constraints on the mean matter and dark energy densities, with a peak sensitivity for dark energy work at redshifts midway between those of supernovae and baryon acoustic oscillation/weak lensing/cluster number counts experiments. In combination, these experiments should enable a precise measurement of the evolution of dark energy. (Abridged)

  14. High Mass X-ray Binaries: Progenitors of double neutron star systems

    E-Print Network [OSTI]

    Chaty, Sylvain

    2015-01-01

    In this review I briefly describe the nature of the three kinds of High-Mass X-ray Binaries (HMXBs), accreting through: (i) Be circumstellar disc, (ii) supergiant stellar wind, and (iii) Roche lobe filling supergiants. A previously unknown population of HMXBs hosting supergiant stars has been revealed in the last years, with multi-wavelength campaigns including high energy (INTEGRAL, Swift, XMM, Chandra) and optical/infrared (mainly ESO) observations. This population is divided between obscured supergiant HMXBs, and supergiant fast X-ray transients (SFXTs), characterized by short and intense X-ray flares. I discuss the characteristics of these types of supergiant HMXBs, propose a scenario describing the properties of these high-energy sources, and finally show how the observations can constrain the accretion models (e.g. clumpy winds, magneto-centrifugal barrier, transitory accretion disc, etc). Because they are the likely progenitors of Luminous Blue Variables (LBVs), and also of double neutron star systems,...

  15. Hydrogen deficient donors in low-mass X-ray binaries

    E-Print Network [OSTI]

    Gijs Nelemans

    2007-11-05

    A number of X-ray binaries (neutron stars or black holes accreting from a companion star) have such short orbital periods that ordinary, hydrogen rich, stars do not fit in. Instead the mass-losing star must be a compact, evolved star, leading to the transfer of hydrogen deficient material to the neutron star. I discuss the current knowledge of these objects, with focus on optical spectroscopy.

  16. The Secondary Star in Cataclysmic Variables and Low Mass X-ray Binaries

    E-Print Network [OSTI]

    D. A. Smith; V. S. Dhillon

    1998-08-20

    We critically re-examine the available data on the spectral types, masses and radii of the secondary stars in cataclysmic variables (CVs) and low-mass X-ray binaries (LMXBs), using the new catalogue of Ritter & Kolb (1998) as a starting point. We find there are 55 reliable spectral type determinations and only 14 reliable mass determinations of CV secondary stars (10 and 5, respectively, in the case of LMXBs). We derive new spectral type-period, mass-radius, mass-period and radius-period relations, and compare them with theoretical predictions. We find that CV secondary stars with orbital periods shorter than 7-8 hours are, as a group, indistinguishable from main sequence stars in detached binaries. We find it is not valid, however, to estimate the mass from the spectral type of the secondary star in CVs or LMXBs. We find that LMXB secondary stars show some evidence for evolution, with secondary stars which are slightly too large for their mass. We show how the masses and radii of the secondary stars in CVs can be used to test the validity of the disrupted magnetic braking model of CV evolution, but we find that the currently available data are not sufficiently accurate or numerous to allow such an analysis. As well as considering secondary star masses, we also discuss the masses of the white dwarfs in CVs, and find mean values of M_1 = 0.69+/-0.13 M_sun below the period gap, and M_1 = 0.80+/-0.22 M_sun above the period gap.

  17. Is irradiation important for the secular evolution of low-mass X-ray binaries?

    E-Print Network [OSTI]

    H. Ritter

    2008-03-14

    It is argued that irradiation in low-mass X-ray binaries (LMXBs) caused by accretion-generated X-rays can not only change the optical appearance of LMXBs but also their outburst properties and possibly also their long-term evolution. Irradiation during an outburst of the outer parts of the accretion disc in a transient LMXB leads to drastic changes in the outburst properties. As far as the secular evolution of such systems is concerned, these changes can result in enhanced loss of mass and angular momentum from the system and, most important, in neutron star LMXBs in a much less efficient use of the transferred matter to spin up the neutron star to a ms-pulsar. Irradiation of the donor star can destabilize mass transfer and lead to irradiation-driven mass transfer cycles, i.e. to a secular evolution which differs drastically from an evolution in which irradiation is ignored. It is argued that irradiation-driven mass transfer cycles cannot occur in systems which are transient because of disc instabilities, i.e. in particular in long-period LMXBs with a giant donor. It is furthermore shown that for irradiating either the disc or the donor star, direct irradiation alone is insufficient. Rather, indirect irradiation via scattered accretion luminosity must play an important role in transient LMXBs and is, in fact, necessary to destabilize mass transfer in short-period systems by irradiating the donor star. Whether and to what extent irradiation in LMXBs does change their secular evolution depends on a number of unsolved problems which are briefly discussed at the end of this article.

  18. A new multiparametric topological method for determining the primary cosmic ray mass composition in the knee energy region

    E-Print Network [OSTI]

    M. Ambrosio; C. Aramo; D. D'Urso; A. D. Erlykin; F. Guarino; A. Insolia

    2004-10-07

    The determination of the primary cosmic ray mass composition from the characteristics of extensive air showers (EAS), obtained at an observation level in the lower half of the atmosphere, is still an open problem. In this work we propose a new method of the Multiparametric Topological Analysis and show its applicability for the determination of the mass composition of the primary cosmic rays at the PeV energy region.

  19. LONG-DURATION X-RAY FLASH AND X-RAY-RICH GAMMA-RAY BURSTS FROM LOW-MASS POPULATION III STARS

    SciTech Connect (OSTI)

    Nakauchi, Daisuke; Kashiyama, Kazumi; Nakamura, Takashi [Department of Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Suwa, Yudai [Yukawa Institute for Theoretical Physics, Kyoto University, Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto 606-8502 (Japan); Sakamoto, Takanori [Center for Research and Exploration in Space Science and Technology (CRESST), NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

    2012-11-10

    Recent numerical simulations suggest that Population III (Pop III) stars were born with masses not larger than {approx}100 M {sub Sun} and typically {approx}40 M {sub Sun }. By self-consistently considering the jet generation and propagation in the envelope of these low-mass Pop III stars, we find that a Pop III blue supergiant star has the possibility of giving rise to a gamma-ray burst (GRB) even though it keeps a massive hydrogen envelope. We evaluate observational characteristics of Pop III GRBs and predict that Pop III GRBs have a duration of {approx}10{sup 5} s in the observer frame and a peak luminosity of {approx}5 Multiplication-Sign 10{sup 50} erg s{sup -1}. Assuming that the E {sub p}-L {sub p} (or E {sub p}-E {sub {gamma},iso}) correlation holds for Pop III GRBs, we find that the spectrum peak energy falls at approximately a few keV (or {approx}100 keV) in the observer frame. We discuss the detectability of Pop III GRBs by future satellite missions such as EXIST and Lobster. If the E {sub p}-E {sub {gamma},iso} correlation holds, we have the possibility to detect Pop III GRBs at z {approx} 9 as long-duration X-ray-rich GRBs by EXIST. Conversely, if the E {sub p}-L {sub p} correlation holds, we have the possibility to detect Pop III GRBs up to z {approx} 19 as long-duration X-ray flashes by Lobster.

  20. Formation of recollimation shocks in jets of high-mass X-ray binaries

    E-Print Network [OSTI]

    Zdziarski, Andrzej A; Heinz, Sebastian

    2015-01-01

    We study conditions for formation of recollimation shocks in jets interacting with stellar winds in high-mass X-ray binaries. We show the existence of a critical jet power, dependent on the wind rate and velocity and the jet velocity, above which a recollimation shock is not formed. For the jet power below critical, we derive the location of the shock. We test these prediction by 3-D numerical simulations, which confirm the existence and the value of the critical power. We apply our results to Cyg X-1 and Cyg X-3.

  1. Heating and Ionization of the Primordial Intergalactic Medium by High Mass X-ray Binaries

    E-Print Network [OSTI]

    Knevitt, Gillian; Power, Chris; Bolton, James

    2014-01-01

    We investigate the influence of High Mass X-ray Binaries on their high redshift environments. Using a one-dimensional radiative transfer code, we predict the ionization and temperature profiles surrounding a coeval stellar population, composed of main sequence stars and HMXBs, at various times after its formation. We consider both uniform density surroundings, and a cluster embedded in a 10^8 solar mass NFW halo. HMXBs in a constant density environment produce negligible enhanced ionization because of their high-energy SEDs and short lifetimes. In this case, HMXBs only marginally contribute to the local heating rate. For NFW profiles, radiation from main sequence stars cannot prevent the initially ionized volume from recombining since it is unable to penetrate the high density galactic core. However, HMXB photons stall recombinations behind the front, keeping it partially ionized for longer. The increased electron density in these partially ionized regions promotes further cooling, resulting in lower IGM temp...

  2. The relationship between X-ray variability amplitude and black hole mass in active galactic nuclei

    E-Print Network [OSTI]

    O'Neill, P M; Papadakis, I E; Turner, T J; Neill, Paul M. O'; Nandra, Kirpal; Papadakis, Iossif E.

    2005-01-01

    We have investigated the relationship between the 2-10 keV X-ray variability amplitude and black hole mass for a sample of 46 radio-quiet active galactic nuclei observed by ASCA. Thirty-three of the objects in our sample exhibited variability over a time-scale of ~40 ks, and we found a significant anti-correlation between excess variance and mass. Unlike most previous studies, we have quantified the variability using nearly the same time-scale for all objects. Moreover, we provide a prescription for estimating the uncertainties in excess variance which accounts both for measurement uncertainties and for the stochastic nature of the variability. We also present an analytical method to predict the excess variance from a model power spectrum accounting for binning, sampling and windowing effects. Using this, we modelled the variance-mass relation assuming all objects have a universal twice-broken power spectrum, with the position of the breaks being dependent on mass. This accounts for the general form of the re...

  3. Binary orbits as the driver of gamma-ray emission and mass ejection in classical novae

    E-Print Network [OSTI]

    Chomiuk, Laura; Yang, Jun; O'Brien, T J; Paragi, Zsolt; Mioduszewski, Amy J; Beswick, R J; Cheung, C C; Mukai, Koji; Nelson, Thomas; Ribeiro, Valerio A R M; Rupen, Michael P; Sokoloski, J L; Weston, Jennifer; Zheng, Yong; Bode, Michael F; Eyres, Stewart; Roy, Nirupam; Taylor, Gregory B

    2014-01-01

    Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel ~10^(-4) solar masses of material at velocities exceeding 1,000 kilometres per second. However, the mechanism of mass ejection in novae is poorly understood, and could be dominated by the impulsive flash of thermonuclear energy, prolonged optically thick winds, or binary interaction with the nova envelope. Classical novae are now routinely detected in gigaelectronvolt gamma-ray wavelengths, suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the gamma-ray-emitting nova V959 Mon. We find that its ejecta were shaped by the motion of the binary system: some gas was expelled rapidly along the poles as a wind from the white dwarf, while denser material drifted out along the equatorial plane, propelled by orbital motion. At the interface ...

  4. New Results for Two Optically Faint Low Mass X-Ray Binary Systems

    E-Print Network [OSTI]

    Stefanie Wachter

    1997-09-04

    We present optical photometry of the low mass X-ray binary systems GX 349+2 and Ser X-1. Extensive VRI photometry of the faint optical counterpart (V=18.4) to GX 349+2 reveals a period of 22.5 +/- 0.1 h and half-amplitude 0.2 mag. This result confirms and extends our previously reported 22 h period. No color change is detected over the orbit, although the limits are modest. We also report the discovery of two new variable stars in the field of GX 349+2, including a probable W UMa system. Ser X-1 is one of the most intense persistent X-ray burst sources known. It is also one of only three burst systems for which simultaneous optical and X-ray bursts have been observed. The faint blue optical counterpart MM Ser (B~19.2) has long been known to have a companion 2.1" distant. Our images indicate that MM Ser is itself a further superposition of two stars, separated by only 1". At the very least, the ratio of inferred burst to quiescent optical flux is affected by the discovery of this additional component. In the worst case, the wrong object may have previously been assumed as the optical counterpart.

  5. METALLICITY EFFECT ON LOW-MASS X-RAY BINARY FORMATION IN GLOBULAR CLUSTERS

    SciTech Connect (OSTI)

    Kim, D.-W.; Fabbiano, G.; Fragos, T. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)] [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Ivanova, N.; Sivakoff, G. R. [Department of Physics, University of Alberta, Edmonton, AB (Canada)] [Department of Physics, University of Alberta, Edmonton, AB (Canada); Jordan, A. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Santiago (Chile)] [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Santiago (Chile); Voss, R. [Department of Astrophysics/IMAPP, Radboud University, Nijmegen (Netherlands)] [Department of Astrophysics/IMAPP, Radboud University, Nijmegen (Netherlands)

    2013-02-10

    We present comprehensive observational results of the metallicity effect on the fraction of globular clusters (GCs) that contain low-mass X-ray binaries (LMXB), by utilizing all available data obtained with Chandra for LMXBs and Hubble Space Telescope Advanced Camera for Surveys (ACS) for GCs. Our primary sample consists of old elliptical galaxies selected from the ACS Virgo and Fornax surveys. To improve statistics at both the lowest and highest X-ray luminosity, we also use previously reported results from other galaxies. It is well known that the fraction of GCs hosting LMXBs is considerably higher in red, metal-rich, GCs than in blue, metal-poor GCs. In this paper, we test whether this metallicity effect is X-ray luminosity-dependent and find that the effect holds uniformly in a wide luminosity range. This result is statistically significant (at {>=}3{sigma}) in LMXBs with luminosities in the range L {sub X} = 2 Multiplication-Sign 10{sup 37} to 5 Multiplication-Sign 10{sup 38} erg s{sup -1}, where the ratio of GC-LMXB fractions in metal-rich to metal-poor GCs is R = 3.4 {+-} 0.5. A similar ratio is also found at lower (down to 10{sup 36} erg s{sup -1}) and higher luminosities (up to the ULX regime), but with less significance ({approx}2{sigma} confidence). Because different types of LMXBs dominate in different luminosities, our finding requires a new explanation for the metallicity effect in dynamically-formed LMXBs. We confirm that the metallicity effect is not affected by other factors such as stellar age, GC mass, stellar encounter rate, and galacto-centric distance.

  6. DC attenuation meter

    DOE Patents [OSTI]

    Hargrove, Douglas L.

    2004-09-14

    A portable, hand-held meter used to measure direct current (DC) attenuation in low impedance electrical signal cables and signal attenuators. A DC voltage is applied to the signal input of the cable and feedback to the control circuit through the signal cable and attenuators. The control circuit adjusts the applied voltage to the cable until the feedback voltage equals the reference voltage. The "units" of applied voltage required at the cable input is the system attenuation value of the cable and attenuators, which makes this meter unique. The meter may be used to calibrate data signal cables, attenuators, and cable-attenuator assemblies.

  7. X-ray Mass Estimates at $z\\sim0.3$ for the CNOC Cluster Sample

    E-Print Network [OSTI]

    Aaron D. Lewis; E. Ellingson; Simon L. Morris; R. G. Carlberg

    1999-01-06

    Results are presented from the analysis of ROSAT HRI and PSPC observations of the CNOC subsample of the EMSS high redshift galaxy clusters. X-ray surface brightness profiles of 14 clusters with $0.17 < z < 0.55$ are constructed and fit to isothermal $\\beta$ models. Where possible, we use both the HRI and PSPC data to constrain the fit. Under the assumptions of isothermality, hydrostatic equilibrium, and spherical symmetry, we derive total X-ray masses within a range of radii from 141 to $526 h^{-1}_{100}$ kpc. These masses are compared with both the dynamical masses obtained from galaxy velocities and the projected masses from published gravitational lensing studies. We find no systematic bias between X-ray and dynamical methods across the sample, with an average $M_{Dyn}/M_X=1.04\\pm0.07$, although individual clusters exhibit mass discrepancies up to a factor of 2. We estimate that the systematic effects due to cooling flows, non-equilibrium systems and temperature gradients affect the average mass ratio by no more than $15-20%$. Weak gravitational lensing masses appear to be systematically higher than X-ray results by factors of $\\sim50%$, while strong lensing estimates show larger discrepancies (factors of $\\sim2.5$). However, these comparisons are complicated by the need to extrapolate the X-ray data to larger or smaller radii. X-ray derived cluster gas masses are calculated, from which we obtain a cluster baryon fraction of $\\sim5%h^{-3/2}_{100}$, yielding $\\Omega_0 \\sim0.3h^{-1/2}_{100}$.

  8. The Low-Mass X-ray Binary-Globular Cluster connection in NGC 4472

    E-Print Network [OSTI]

    Arunav Kundu; Tom Maccarone; Steve Zepf

    2002-06-13

    We have analyzed the low mass X-ray binary (LMXB) candidates in a Chandra observation of the giant elliptical galaxy NGC 4472. In a region observed by the Hubble Space Telescope, approximately 40% of the bright (L_X >= 10^37 ergs/s) LMXBs are associated with optically identified globular clusters (GC). This is significantly higher than the fraction of bright LMXBs in Galactic GCs and confirms that GCs are the dominant sites of LMXB formation in early type galaxies. The approximately 4% of NGC 4472 GCs hosting bright LMXBs, on the other hand, is remarkably similar to the fraction of GCs with LMXBs in every other galaxy. Although statistical tests suggest that the luminosity of a cluster is an important driver of LMXB formation in GCs, this appears largely to be a consequence of the greater number of stars in bright clusters. The metallicity of GCs is a strong determinant of LMXB specific frequency, with metal-rich clusters about 3 times more likely to host LMXBs than metal-poor ones. There are weaker dependences on the size of a GC and its distance from the center of the galaxy. The X-ray luminosity does not depend significantly on the properties of the host GC. Furthermore, the spatial distribution and X-ray luminosity function of LMXBs within and outside GCs are indistinguishable. The X-ray luminosity function of both GC-LMXBs and non-GC-LMXBs reveal a break at approximately 3x10^38 ergs/s strongly suggesting that the brightest LMXBs are black hole accretors.

  9. Attenuation of Beaming Oscillations Near Neutron Stars

    E-Print Network [OSTI]

    M. Coleman Miller

    2000-07-17

    Observations with RXTE have revealed kilohertz quasi-periodic brightness oscillations (QPOs) from nearly twenty different neutron-star low-mass X-ray binaries (LMXBs). These frequencies often appear as a pair of kilohertz QPOs in a given power density spectrum. In many models the higher-frequency of these QPOs is a beaming oscillation at the frequency of a nearly circular orbit at some radius near the neutron star. In such models it is expected that there will also be beaming oscillations at the stellar spin frequency and at overtones of the orbital frequency, but no strong QPOs have been detected at these frequencies. We therefore examine the processes that can attenuate beaming oscillations near neutron stars, and in doing so extend the work on this subject that was initiated by the discovery of lower-frequency QPOs from LMXBs. Among our main results are (1)in a spherical scattering cloud, all overtones of rotationally modulated beaming oscillations are attenuated strongly, not just the even harmonics, and (2)it is possible to have a relatively high-amplitude modulation near the star at, e.g., the stellar spin frequency, even if no peak at that frequency is detectable in a power density spectrum taken at infinity. We discuss the application of these results to modeling of kilohertz QPOs.

  10. The mass and the radius of the neutron star in the transient low mass X-ray binary SAX J1748.9-2021

    E-Print Network [OSTI]

    Yanikoglu, Berrin

    .9-2021 Tolga G¨uver1 , Feryal ¨Ozel2,3 ABSTRACT We use time resolved spectroscopy of thermonuclear X-ray bursts of thermonuclear flashes on the neutron star surface (Galloway et al. 2008). In this paper, we use the time-resolved spectroscopy of a subsample of these thermonuclear bursts to determine the mass and radius of the neutron star

  11. Formation of Black Hole Low-Mass X-ray Binaries in Hierarchical Triple Systems

    E-Print Network [OSTI]

    Naoz, Smadar; Geller, Aaron; Stephan, Alexander P; Rasio, Frederic A

    2015-01-01

    The formation of Black Hole (BH) Low-Mass X-ray Binaries (LMXB) poses a theoretical challenge, as low-mass companions are not expected to survive the common-envelope scenario with the BH progenitor. Here we propose a formation mechanism that skips the common-envelope scenario and relies on triple-body dynamics. We study the evolution of hierarchical triples, following the secular dynamical evolution up to the octupole-level of approximation, including general relativity, tidal effects and post-main-sequence evolution, such as mass loss, changes to stellar radii and supernovae. During the dynamical evolution of the triple system, the "eccentric Kozai-Lidov" mechanism can cause large eccentricity excitations in the LMXB progenitor, resulting in three main BH-LMXB formation channels. Here we define BH-LMXB candidates as systems where the inner BH companion star crosses its Roche limit. In the "eccentric" channel (~ 81% of the LMXBs in our simulations), the donor star crosses its Roche limit during an extreme ecc...

  12. Radiative neutrino mass and 3.5 keV X-ray line

    E-Print Network [OSTI]

    Baek, Seungwon

    2015-01-01

    We consider an extension of Zee-Babu model to explain the smallness of neutrino masses. (1) We extend the lepton number symmetry of the original model to local $B-L$ symmetry. (2) We introduce three Dirac dark matter candidates with flavor-dependent $B-L$ charges. After the spontaneous breaking of $B-L$, a discrete symmetry $Z_6$ remains, which guarantees the stability of dark matter. Then the model can explain the 3.5 keV X-ray line signal with decaying dark matter. We also introduce a real scalar field which is singlet under both the SM and $U(1)_{B-L}$ and can explain the current relic abundance of the Dirac fermionic DMs. If the mixing with the SM Higgs boson is small, it does not contribute to DM direct detection. The main contribution to the scattering of DM off atomic nuclei comes from the exchange of $U(1)_{B-L}$ gauge boson, $Z'$, and is suppressed below current experimental bound when $Z'$ mass is heavy ($\\gtrsim 10$ TeV). If the singlet scalar mass is about 0.1--10 MeV, DM self-interaction can be l...

  13. MASS MEASUREMENT OF {sup 45}Cr AND ITS IMPACT ON THE Ca-Sc CYCLE IN X-RAY BURSTS

    SciTech Connect (OSTI)

    Yan, X. L.; Xu, H. S.; Litvinov, Yu. A.; Zhang, Y. H.; Tu, X. L.; Zhou, X. H.; He, J. J.; Sun, Y.; Wang, M.; Yuan, Y. J.; Xia, J. W.; Yang, J. C.; Jia, G. B.; Hu, Z. G.; Ma, X. W.; Mao, R. S.; Schatz, H.; Blaum, K.; Sun, B. H.; Audi, G.; and others

    2013-03-20

    Masses of neutron-deficient {sup 58}Ni projectile fragments have been measured at the HIRFL-CSR facility in Lanzhou, China employing the isochronous mass spectrometry technique. Masses of a series of short-lived T{sub z} = -3/2 nuclides including the {sup 45}Cr nucleus have been measured with a relative uncertainty of about 10{sup -6}-10{sup -7}. The new {sup 45}Cr mass turned out to be essential for modeling the astrophysical rp-process. In particular, we find that the formation of the predicted Ca-Sc cycle in X-ray bursts can be excluded.

  14. First superburst from a classical low-mass X-ray binary transient

    E-Print Network [OSTI]

    L. Keek; J. J. M. in 't Zand; E. Kuulkers; A. Cumming; E. F. Brown; M. Suzuki

    2007-11-27

    We report the analysis of the first superburst from a transiently accreting neutron star system with the All-Sky Monitor (ASM) on the Rossi X-ray Timing Explorer. The superburst occurred 55 days after the onset of an accretion outburst in 4U 1608-522. During that time interval, the accretion rate was at least 7% of the Eddington limit. The peak flux of the superburst is 22 to 45% of the Eddington limit, and its radiation energy output is between 4e41 and 9e41 erg for a distance of 3.2 kpc. Fits of cooling models to the superburst light curve indicate an ignition column depth between 1.5e12 and 4.1e12 g/cm2. Extrapolating the accretion history observed by the ASM, we derive that this column was accreted over a period of 26 to 72 years. The superburst characteristics are consistent with those seen in other superbursting low-mass X-ray binaries. However, the transient nature of the hosting binary presents significant challenges for superburst theory, requiring additional ingredients for the models. The carbon that fuels the superburst is thought to be produced mostly during the accretion outbursts and destroyed in the frequent type-I X-ray bursts. Mixing and sedimentation of the elements in the neutron star envelope may significantly influence the balance between the creation and destruction of carbon. Furthermore, predictions for the temperature of the neutron star crust fail to reach the values required for the ignition of carbon at the inferred column depth.

  15. A new symbiotic low mass X-ray binary system: 4U 1954+319

    E-Print Network [OSTI]

    F. Mattana; D. Gotz; M. Falanga; F. Senziani; A. De Luca; P. Esposito; P. A. Caraveo

    2006-10-05

    4U 1954+319 was discovered 25 years ago, but only recently has a clear picture of its nature begun to emerge. We present for the first time a broad-band spectrum of the source and a detailed timing study using more than one year of monitoring data. The timing and spectral analysis was done using publicly available Swift, INTEGRAL, BeppoSAX, and RXTE/ASM data in the 0.7-150 keV energy band. The source spectrum is described well by a highly absorbed (N_H~10^23 cm^-2) power law with a high-energy exponential cutoff around 15 keV. An additional black body component is needed below 3 keV to account for a soft excess. The derived ~5 hr periodicity, with a spin-up timescale of ~25 years, could be identified as the neutron star spin period. The spectral and timing characteristics indicate that we are dealing both with the slowest established wind-accreting X-ray pulsar and with the second confirmed member of the emerging class dubbed "symbiotic low mass X-ray binaries" to host a neutron star.

  16. Prospects for measuring neutron-star masses and radii with X-ray pulse profile modeling

    SciTech Connect (OSTI)

    Psaltis, Dimitrios; Özel, Feryal [Astronomy Department, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Chakrabarty, Deepto, E-mail: dpsaltis@email.arizona.edu, E-mail: fozel@email.arizona.edu, E-mail: deepto@mit.edu [Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2014-06-01

    Modeling the amplitudes and shapes of the X-ray pulsations observed from hot, rotating neutron stars provides a direct method for measuring neutron-star properties. This technique constitutes an important part of the science case for the forthcoming NICER and proposed LOFT X-ray missions. In this paper, we determine the number of distinct observables that can be derived from pulse profile modeling and show that using only bolometric pulse profiles is insufficient for breaking the degeneracy between inferred neutron-star radius and mass. However, we also show that for moderately spinning (300-800 Hz) neutron stars, analysis of pulse profiles in two different energy bands provides additional constraints that allow a unique determination of the neutron-star properties. Using the fractional amplitudes of the fundamental and the second harmonic of the pulse profile in addition to the amplitude and phase difference of the spectral color oscillations, we quantify the signal-to-noise ratio necessary to achieve a specified measurement precision for neutron star radius. We find that accumulating 10{sup 6} counts in a pulse profile is sufficient to achieve a ? 5% uncertainty in the neutron star radius, which is the level of accuracy required to determine the equation of state of neutron-star matter. Finally, we formally derive the background limits that can be tolerated in the measurements of the various pulsation amplitudes as a function of the system parameters.

  17. Cyclotron line and wind studies of galactic high mass X- ray binaries

    E-Print Network [OSTI]

    Suchy, Slawomir

    2011-01-01

    missions detected Gamma Ray Burst afterglows and discoveredUS launched the Swift Gamma-Ray Burst Mission (Gehrels etal. , 2004) to study gamma-ray bursts and their afterglows.

  18. Low-Mass X-Ray Binary MAXI J1421-613 Observed by MAXI GSC and Swift XRT

    E-Print Network [OSTI]

    Serino, Motoko; Ueda, Yoshihiro; Matsuoka, Masaru; Negoro, Hitoshi; Yamaoka, Kazutaka; Kennea, Jamie A; Fukushima, Kosuke; Nagayama, Takahiro

    2015-01-01

    Monitor of All sky X-ray Image (MAXI) discovered a new outburst of an X-ray transient source named MAXI J1421-613. Because of the detection of three X-ray bursts from the source, it was identified as a neutron star low-mass X-ray binary. The results of data analyses of the MAXI GSC and the Swift XRT follow-up observations suggest that the spectral hardness remained unchanged during the first two weeks of the outburst. All the XRT spectra in the 0.5-10 keV band can be well explained by thermal Comptonization of multi-color disk blackbody emission. The photon index of the Comptonized component is $\\approx$ 2, which is typical of low-mass X-ray binaries in the low/hard state. Since X-ray bursts have a maximum peak luminosity, it is possible to estimate the (maximum) distance from its observed peak flux. The peak flux of the second X-ray burst, which was observed by the GSC, is about 5 photons cm$^{-2}$ s$^{-1}$. By assuming a blackbody spectrum of 2.5 keV, the maximum distance to the source is estimated as 7 kpc...

  19. Collective properties of neutron-star X-ray binary populations of galaxies. II. Pre-low-mass X-ray binary properties, formation rates, and constraints

    SciTech Connect (OSTI)

    Bhadkamkar, H. [Astronomy and Astrophysics, Raman Research Institute, Bengaluru 560080 (India); Ghosh, P. [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Mumbai 400005 (India)

    2014-04-01

    We continue our exploration of the collective properties of neutron-star X-ray binaries in the stellar fields (i.e., outside globular clusters) of normal galaxies. In Paper I of this series, we considered high-mass X-ray binaries (HMXBs). In this paper (Paper II), we consider low-mass X-ray binaries (LMXBs), whose evolutionary scenario is very different from that of HMXBs. We consider the evolution of primordial binaries up to the stage where the neutron star just formed in the supernova explosion of the primary is in a binary with its low-mass, unevolved companion, and this binary has circularized tidally, producing what we call a pre-low-mass X-ray binary (pre-LMXB). We study the constraints on the formation of such pre-LMXBs in detail (since these are low-probability events), and calculate their collective properties and formation rates. To this end, we first consider the changes in the binary parameters in the various steps involved, viz., the common-envelope phase, the supernova, and the tidal evolution. This naturally leads to a clarification of the constraints. We then describe our calculation of the evolution of the distributions of primordial binary parameters into those of pre-LMXB parameters, following the standard evolutionary scenario for individual binaries. We display the latter as both bivariate and monovariate distributions, discuss their essential properties, and indicate the influences of some essential factors on these. Finally, we calculate the formation rate of these pre-LMXBs. The results of this paper will be used in a subsequent one to compute the expected X-ray luminosity function of LMXBs.

  20. Pressure surge attenuator

    DOE Patents [OSTI]

    Christie, Alan M. (Swissvale, PA); Snyder, Kurt I. (Murrysville, PA)

    1985-01-01

    A pressure surge attenuation system for pipes having a fluted region opposite crushable metal foam. As adapted for nuclear reactor vessels and heads, crushable metal foam is disposed to attenuate pressure surges.

  1. The lowest-mass stellar black holes: catastrophic death of neutron stars in gamma-ray bursts

    E-Print Network [OSTI]

    K. Belczynski; R. O'Shaughnessy; V. Kalogera; F. Rasio; R. Taam; T. Bulik

    2008-04-16

    Mergers of double neutron stars are considered the most likely progenitors for short gamma-ray bursts. Indeed such a merger can produce a black hole with a transient accreting torus of nuclear matter (Lee & Ramirez-Ruiz 2007, Oechslin & Janka 2006), and the conversion of a fraction of the torus mass-energy to radiation can power a gamma-ray burst (Nakar 2006). Using available binary pulsar observations supported by our extensive evolutionary calculations of double neutron star formation, we demonstrate that the fraction of mergers that can form a black hole -- torus system depends very sensitively on the (largely unknown) maximum neutron star mass. We show that the available observations and models put a very stringent constraint on this maximum mass under the assumption that a black hole formation is required to produce a short gamma-ray burst in a double neutron star merger. Specifically, we find that the maximum neutron star mass must be within 2 - 2.5 Msun. Moreover, a single unambiguous measurement of a neutron star mass above 2.5 Msun would exclude a black hole -- torus central engine model of short gamma-ray bursts in double neutron star mergers. Such an observation would also indicate that if in fact short gamma-ray bursts are connected to neutron star mergers, the gamma-ray burst engine is best explained by the lesser known model invoking a highly magnetized massive neutron star (e.g., Usov 1992; Kluzniak & Ruderman 1998; Dai et al. 2006; Metzger, Quataert & Thompson 2007).

  2. Average mass composition of primary cosmic rays in the superhigh energy region by Yakutsk complex EAS array data

    E-Print Network [OSTI]

    S. P. Knurenko; A. A. Ivanov; A. V. Sabourov; I. Ye. Sleptsov

    2007-11-19

    The characteristics relating to the lateral and longitudinal development of EAS in the energy region of 10^15-10^19eV have been analyzed in the framework of the QGSJET model and of mass composition of primary cosmic rays. It is found that at E(0) >= 5*10^15eV the mean mass composition of primary cosmic rays begins to vary as indicated by a rise of with increasing energy. The maximum value of is observed at E(0) ~ (5-50)*10^16eV. It is confirmed by data of many compact EAS arrays and does not contradict an anomalous diffusion model of cosmic ray propagation in our Galaxy. In the superhigh energy region (>=10^18eV) the value begins to decrease, i.e. the mass composition becomes lighter and consists of protons and nuclei of He and C. It does not contradict our earlier estimations for the mass composition and points to a growing role of the metagalactic component of cosmic rays in the superhigh energy region.

  3. High Mass X-ray Binaries: A Hunt for Optical Variability and Periodicity A study on BD+53 2262

    E-Print Network [OSTI]

    Hart, Gus

    and a compact object, mainly a neutron star. The optical companion of the system is spinning quite rapidly the last several years BYU has monitored several high mass X-ray binary systems. The three systems between them. We also have plans to continue monitoring these systems by using the 16 inch David Derrick

  4. X-RAY ECLIPSE DIAGNOSIS OF THE EVOLVING MASS LOSS IN THE RECURRENT NOVA U SCORPII 2010

    SciTech Connect (OSTI)

    Takei, D.; Drake, J. J. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Tsujimoto, M. [Japan Aerospace Exploration Agency, Institute of Space and Astronautical Science, 3-1-1 Yoshino-dai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Ness, J.-U. [European Space Agency, XMM-Newton Observatory SOC, SRE-OAX, Apartado 78, E-28691 Villanueva de la Canada, Madrid (Spain); Osborne, J. P. [Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH (United Kingdom); Starrfield, S. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Kitamoto, S., E-mail: dtakei@head.cfa.harvard.edu [Department of Physics, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima, Tokyo 171-8501 (Japan)

    2013-05-20

    We report the Suzaku detection of the earliest X-ray eclipse seen in the recurrent nova U Scorpii 2010. A target-of-opportunity observation 15 days after the outburst found a 27% {+-} 5% dimming in the 0.2-1.0 keV energy band at the predicted center of an eclipse. In comparison with the X-ray eclipse depths seen at two later epochs by XMM-Newton, the source region shrank by about 10%-20% between days 15 and 35 after the outburst. The X-ray eclipses appear to be deeper than or similar to contemporaneous optical eclipses, suggesting the X-ray and optical source region extents are comparable on day 15. We raise the possibility of the energy dependency in the photon escape regions, and that this would be a result of the supersoft X-ray opacity being higher than the Thomson scattering opacity at the photosphere due to bound-free transitions in abundant metals that are not fully ionized. Assuming a spherically symmetric model, we constrain the mass-loss rate as a function of time. For a ratio of actual to Thomson opacity of 10-100 in supersoft X-rays, we find an ejecta mass of about 10{sup -7}-10{sup -6} M{sub Sun }.

  5. X-ray radiography for container inspection

    DOE Patents [OSTI]

    Katz, Jonathan I. (Clayton, MO); Morris, Christopher L. (Los Alamos, NM)

    2011-06-07

    Arrangements of X-ray inspection systems are described for inspecting high-z materials in voluminous objects such as containers. Inspection methods may involve generating a radiographic image based on detected attenuation corresponding to a pulsed beams of radiation transmitted through a voluminous object. The pulsed beams of radiation are generated by a high-energy source and transmitted substantially downward along an incident angle, of approximately 1.degree. to 30.degree., to a vertical axis extending through the voluminous object. The generated radiographic image may be analyzed to detect on localized high attenuation representative of high-z materials and to discriminate high-z materials from lower and intermediate-z materials on the basis of the high density and greater attenuation of high-z material for higher energy (3-10 MeV) X-rays, and the compact nature of threatening masses of fissionable materials.

  6. On evolution of Primary Cosmic Ray mass composition in the energy region $10^{14}-10^{16}$ eV

    E-Print Network [OSTI]

    Yu. F. Novoseltsev; G. M. Vereshkov

    2013-11-16

    A new method of determining Primary Cosmic Ray mass composition is proposed. The method is based on quasi-localization of the integral equation for the Extensive Air Showers spectrum versus the total number of high energy muons ($E_\\mu \\geqslant 235$ GeV) and an expansion of the experimentally measured spectrum in spectra of five group of primary nuclei. The cosmic ray mass composition is established in the energy region $10^{14}-10^{16}$ eV. In the region $10^{15}-10^{16}$ eV our analysis points to a lightening of the mass composition from $p+\\alpha \\simeq 0.54,\\ \\langle \\ln A \\rangle \\simeq 1.97$ to $p+\\alpha \\simeq 0.69,\\ \\langle \\ln A \\rangle\\simeq 1.56$.

  7. K{sub ?} x-ray imaging of laser-irradiated, limited-mass zirconium foils

    SciTech Connect (OSTI)

    Storm, M.; Orban, C.; Jiang, S.; Freeman, R. R.; Akli, K. [Department of Physics, The Ohio State University, 191 West Woodruff Road, Columbus, Ohio 43210 (United States); Eichman, B.; Fiksel, G.; Stoeckl, C.; Theobald, W.; Delettrez, J. A. [The Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Dyer, G.; Ditmire, T. [The Texas Center of High Energy Density Science, The University of Texas at Austin, 2511 Speedway Street, Austin, Texas 78712 (United States); Stephens, R. [General Atomics, 3550 General Atomics Court, San Diego, California 92121-1200 (United States)

    2014-07-15

    X-ray fluorescence measurements to determine the effect of target heating on imaging efficiency, at a photon energy of 15.7 keV corresponding to the K{sub ?} line of zirconium, have been carried out using limited-mass foils irradiated by the Texas Petawatt Laser. Zirconium foils that ranged in volume from 3000?×?3000?×?21 ?m{sup 3} to 150?×?150?×?6 ?m{sup 3} were irradiated with 100 J, 8 ps-long pulses and a mean intensity of 4?×?10{sup 19} W/cm{sup 2}. The K{sub ?} emission was measured simultaneously using a highly ordered pyrolytic graphite crystal spectrometer and a curved quartz imaging crystal. The measured ratio of the integrated image signal to the integrated spectral signal was, within the experimental error, constant, indicating that the imaging efficiency's dependence on temperature is weak throughout the probed range. Based on our experience of target heating under similar conditions, we estimate a temperature of ?200 eV for the smallest targets. The successful imaging of K{sub ?} emission for temperatures this high represents an important proof of concept for Zr K{sub ?} imaging. At these temperatures, the imaging of K{sub ?} emission from lower-Z materials (such as Cu) is limited by temperature-dependent shifts in the K{sub ?} emission energy.

  8. Quantitative Analysis of the Resolved X-ray Emission Line Profiles of O Stars

    E-Print Network [OSTI]

    Cohen, David

    -rays in context 3. Hot-star winds 4. Emission line shapes: constraints on hot plasma distribution and wind mass-resolution X-ray observations: not enough attenuation of soft X-rays by the overlying wind to accommodate a corona #12;#12;Radiation-driven winds of O and early-B stars blue velocity (km/s) red wavelength O4 I B0

  9. The Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFC Focused on Hanford’s 300 Area Uranium Plume Quality Assurance Project Plan

    SciTech Connect (OSTI)

    Fix, N. J.

    2008-01-31

    The purpose of the project is to conduct research at an Integrated Field-Scale Research Challenge Site in the Hanford Site 300 Area, CERCLA OU 300-FF-5 (Figure 1), to investigate multi-scale mass transfer processes associated with a subsurface uranium plume impacting both the vadose zone and groundwater. The project will investigate a series of science questions posed for research related to the effect of spatial heterogeneities, the importance of scale, coupled interactions between biogeochemical, hydrologic, and mass transfer processes, and measurements/approaches needed to characterize a mass-transfer dominated system. The research will be conducted by evaluating three (3) different hypotheses focused on multi-scale mass transfer processes in the vadose zone and groundwater, their influence on field-scale U(VI) biogeochemistry and transport, and their implications to natural systems and remediation. The project also includes goals to 1) provide relevant materials and field experimental opportunities for other ERSD researchers and 2) generate a lasting, accessible, and high-quality field experimental database that can be used by the scientific community for testing and validation of new conceptual and numerical models of subsurface reactive transport.

  10. Variable laser attenuator

    DOE Patents [OSTI]

    Foltyn, S.R.

    1987-05-29

    The disclosure relates to low loss, high power variable attenuators comprising one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength. 9 figs.

  11. The Mass and Radius of the Neutron Star in the Bulge Low-Mass X-ray Binary KS 1731-260

    E-Print Network [OSTI]

    Feryal Ozel; Andrew Gould; Tolga Guver

    2011-04-26

    Measurements of neutron star masses and radii are instrumental for determining the equation of state of their interiors, understanding the dividing line between neutron stars and black holes, and for obtaining accurate statistics of source populations in the Galaxy. We report here on the measurement of the mass and radius of the neutron star in the low-mass X-ray binary KS 1731-260. The analysis of the spectroscopic data on multiple thermonuclear bursts yields well-constrained values for the apparent angular area and the Eddington flux of the source, both of which depend in a distinct way on the mass and radius of the neutron star. The binary KS 1731-260 is in the direction of the Galactic bulge, allowing a distance estimate based on the density of stars in that direction. Making use of the Han & Gould model, we determine the probability distribution over the distance to the source, which is peaked at 8 kpc. Combining these measurements, we place a strong upper bound on the radius of the neutron star, R <= 12 km, while confining its mass to M <= 1.8 M_sun.

  12. The 2011 outburst of recurrent nova T Pyx: X-ray observations expose the white dwarf mass and ejection dynamics

    SciTech Connect (OSTI)

    Chomiuk, Laura [Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States); Nelson, Thomas [School of Physics and Astronomy, University of Minnesota, 115 Church Street SE, Minneapolis, MN 55455 (United States); Mukai, Koji [CRESST and X-ray Astrophysics Laboratory, NASA/GSFC, Greenbelt, MD 20771 (United States); Sokoloski, J. L.; Weston, Jennifer [Columbia Astrophysics Laboratory, Columbia University, New York, NY (United States); Rupen, Michael P.; Mioduszewski, Amy J.; Krauss, Miriam I. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Page, Kim L.; Osborne, Julian P. [Department of Physics and Astronomy, University of Leicester, Leicester, LE1 7RH (United Kingdom); Kuulkers, Erik [European Space Astronomy Centre (ESA/ESAC), Science Operations Department, E-28691 Villanueva de la Caada, Madrid (Spain); Roy, Nirupam, E-mail: chomiuk@pa.msu.edu [Max Planck Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany)

    2014-06-20

    The recurrent nova T Pyx underwent its sixth historical outburst in 2011, and became the subject of an intensive multi-wavelength observational campaign. We analyze data from the Swift and Suzaku satellites to produce a detailed X-ray light curve augmented by epochs of spectral information. X-ray observations yield mostly non-detections in the first four months of outburst, but both a super-soft and hard X-ray component rise rapidly after Day 115. The super-soft X-ray component, attributable to the photosphere of the nuclear-burning white dwarf, is relatively cool (?45 eV) and implies that the white dwarf in T Pyx is significantly below the Chandrasekhar mass (?1 M {sub ?}). The late turn-on time of the super-soft component yields a large nova ejecta mass (? 10{sup –5} M {sub ?}), consistent with estimates at other wavelengths. The hard X-ray component is well fit by a ?1 keV thermal plasma, and is attributed to shocks internal to the 2011 nova ejecta. The presence of a strong oxygen line in this thermal plasma on Day 194 requires a significantly super-solar abundance of oxygen and implies that the ejecta are polluted by white dwarf material. The X-ray light curve can be explained by a dual-phase ejection, with a significant delay between the first and second ejection phases, and the second ejection finally released two months after outburst. A delayed ejection is consistent with optical and radio observations of T Pyx, but the physical mechanism producing such a delay remains a mystery.

  13. Gamma-rays from the vicinity of accreting neutron stars inside compact high-mass X-ray binaries

    E-Print Network [OSTI]

    W. Bednarek

    2008-11-25

    Dense wind of a massive star can be partially captured by a neutron star (NS) inside a compact binary system. Depending on the parameters of NS and the wind, the matter can penetrate the inner NS magnetosphere. At some distance from the NS a very turbulent and magnetized transition region is formed due to the balance between the magnetic pressure and the pressure inserted by accreting matter. This region provides good conditions for acceleration of particles to relativistic energies. The matter at the transition region can farther accrete onto the NS surface (the accretor phase) or is expelled from the NS vicinity (the propeller phase). We consider the consequences of acceleration of electrons at the transition region concentrating on the situation in which at least part of the matter falls onto the NS surface. This matter creates a hot spot on the NS surface which emits thermal radiation. Relativistic electrons lose energy on the synchrotron process and the inverse Compton (IC) scattering of this thermal radiation. We calculate the synchrotron spectra (from X-rays to soft $\\gamma$-rays) and IC spectra (above a few tens MeV) expected in such a scenario. It is argued that a population of recently discovered massive binaries by the INTEGRAL observatory, which contain neutron stars hidden inside dense stellar winds of massive stars, can be detectable by the recently launched {\\it Fermi} LAT telescope at GeV energy range. As an example, we predict the expected $\\gamma$-ray flux from recently discovered source IGR J19140+0951.

  14. X-ray Eclipse Diagnosis of the Evolving Mass Loss in the Recurrent Nova U Scorpii 2010

    E-Print Network [OSTI]

    Takei, D; Tsujimoto, M; Ness, J -U; Osborne, J P; Starrfield, S; Kitamoto, S

    2013-01-01

    We report the Suzaku detection of the earliest X-ray eclipse seen in the recurrent nova U Scorpii 2010. A target-of-opportunity observation 15 days after the outburst found a 27+/-5% dimming in the 0.2-1.0 keV energy band at the predicted center of an eclipse. In comparison with the X-ray eclipse depths seen at two later epochs by XMM-Newton, the source region shrank by about 10-20% between days 15 and 35 after the outburst. The X-ray eclipses appear to be deeper than or similar to contemporaneous optical eclipses, suggesting the X-ray and optical source region extents are comparable on day 15. We raise the possibility of the energy dependency in the photon escape regions, and that this would be a result of the supersoft X-ray opacity being higher than the Thomson scattering optical opacity at the photosphere due to bound-free transitions in abundant metals that are not fully ionized. Assuming a spherically symmetric explosion model, we constrain the mass-loss rate as a function of time. For a ratio of actual...

  15. Mass-ablation-rate measurements in direct-drive cryogenic implosions using x-ray self-emission images

    SciTech Connect (OSTI)

    Davis, A. K., E-mail: adavi@lle.rochester.edu; Michel, D. T.; Hu, S. X.; Craxton, R. S.; Epstein, R.; Goncharov, V. N.; Igumenshchev, I. V.; Sangster, T. C.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636 (United States)

    2014-11-15

    A technique to measure the mass ablation rate in direct-drive inertial confinement fusion implosions using a pinhole x-ray framing camera is presented. In target designs consisting of two layers of different materials, two x-ray self-emission peaks from the coronal plasma were measured once the laser burned through the higher-Z outer layer. The location of the inner peak is related to the position of the ablation front and the location of the outer peak corresponds to the position of the interface of the two layers in the plasma. The emergence of the second peak was used to measure the burnthrough time of the outer layer, giving the average mass ablation rate of the material and instantaneous mass remaining. By varying the thickness of the outer layer, the mass ablation rate can be obtained as a function of time. Simulations were used to validate the methods and verify that the measurement techniques are not sensitive to perturbation growth at the ablation surface.

  16. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume January 2011 to January 2012

    SciTech Connect (OSTI)

    Zachara, John M.; Bjornstad, Bruce N.; Christensen, John N.; Conrad, Mark S.; Fredrickson, Jim K.; Freshley, Mark D.; Haggerty, Roy; Hammond, Glenn E.; Kent, Douglas B.; Konopka, Allan; Lichtner, Peter C.; Liu, Chongxuan; McKinley, James P.; Murray, Christopher J.; Rockhold, Mark L.; Rubin, Yoram; Vermeul, Vincent R.; Versteeg, Roelof J.; Zheng, Chunmiao

    2012-03-05

    The Integrated Field Research Challenge (IFRC) at the Hanford Site 300 Area uranium (U) plume addresses multi-scale mass transfer processes in a complex subsurface biogeochemical setting where groundwater and riverwater interact. A series of forefront science questions on reactive mass transfer motivates research. These questions relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements and approaches needed to characterize and model a mass-transfer dominated biogeochemical system. The project was initiated in February 2007, with CY 2007, CY 2008, CY 2009, and CY 2010 progress summarized in preceding reports. A project peer review was held in March 2010, and the IFRC project acted upon all suggestions and recommendations made in consequence by reviewers and SBR/DOE. These responses have included the development of 'Modeling' and 'Well-Field Mitigation' plans that are now posted on the Hanford IFRC web-site, and modifications to the IFRC well-field completed in CY 2011. The site has 35 instrumented wells, and an extensive monitoring system. It includes a deep borehole for microbiologic and biogeochemical research that sampled the entire thickness of the unconfined 300 A aquifer. Significant, impactful progress has been made in CY 2011 including: (i) well modifications to eliminate well-bore flows, (ii) hydrologic testing of the modified well-field and upper aquifer, (iii) geophysical monitoring of winter precipitation infiltration through the U-contaminated vadose zone and spring river water intrusion to the IFRC, (iv) injection experimentation to probe the lower vadose zone and to evaluate the transport behavior of high U concentrations, (v) extended passive monitoring during the period of water table rise and fall, and (vi) collaborative down-hole experimentation with the PNNL SFA on the biogeochemistry of the 300 A Hanford-Ringold contact and the underlying redox transition zone. The modified well-field has functioned superbly without any evidence for well-bore flows. Beyond these experimental efforts, our site-wide reactive transport models (PFLOTRAN and eSTOMP) have been updated to include site geostatistical models of both hydrologic properties and adsorbed U distribution; and new hydrologic characterization measurements of the upper aquifer. These increasingly robust models are being used to simulate past and recent U desorption-adsorption experiments performed under different hydrologic conditions, and heuristic modeling to understand the complex functioning of the smear zone. We continued efforts to assimilate geophysical logging and 3D ERT characterization data into our site wide geophysical model, with significant and positive progress in 2011 that will enable publication in 2012. Our increasingly comprehensive field experimental results and robust reactive transport simulators, along with the field and laboratory characterization, are leading to a new conceptual model of U(VI) flow and transport in the IFRC footprint and the 300 Area in general, and insights on the microbiological community and associated biogeochemical processes influencing N, S, C, Mn, and Fe. Collectively these findings and higher scale models are providing a unique and unparalleled system-scale understanding of the biogeochemical function of the groundwater-river interaction zone.

  17. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume January 2010 to January 2011

    SciTech Connect (OSTI)

    Zachara, John M.; Bjornstad, Bruce N.; Christensen, John N.; Conrad, Mark S.; Fredrickson, Jim K.; Freshley, Mark D.; Haggerty, Roy; Hammond, Glenn E.; Kent, Douglas B.; Konopka, Allan; Lichtner, Peter C.; Liu, Chongxuan; McKinley, James P.; Murray, Christopher J.; Rockhold, Mark L.; Rubin, Yoram; Vermeul, Vincent R.; Versteeg, Roelof J.; Ward, Anderson L.; Zheng, Chunmiao

    2011-02-01

    The Integrated Field Research Challenge (IFRC) at the Hanford Site 300 Area uranium (U) plume addresses multi-scale mass transfer processes in a complex subsurface hydrogeologic setting where groundwater and riverwater interact. A series of forefront science questions on reactive mass transfer focus research. These questions relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements and approaches needed to characterize and model a mass-transfer dominated system. The project was initiated in February 2007, with CY 2007, CY 2008, and CY 2009 progress summarized in preceding reports. A project peer review was held in March 2010, and the IFRC project has responded to all suggestions and recommendations made in consequence by reviewers and SBR/DOE. These responses have included the development of “Modeling” and “Well-Field Mitigation” plans that are now posted on the Hanford IFRC web-site. The site has 35 instrumented wells, and an extensive monitoring system. It includes a deep borehole for microbiologic and biogeochemical research that sampled the entire thickness of the unconfined 300 A aquifer. Significant, impactful progress has been made in CY 2010 including the quantification of well-bore flows in the fully screened wells and the testing of means to mitigate them; the development of site geostatistical models of hydrologic and geochemical properties including the distribution of U; developing and parameterizing a reactive transport model of the smear zone that supplies contaminant U to the groundwater plume; performance of a second passive experiment of the spring water table rise and fall event with a associated multi-point tracer test; performance of downhole biogeochemical experiments where colonization substrates and discrete water and gas samplers were deployed to the lower aquifer zone; and modeling of past injection experiments for model parameterization, deconvolution of well-bore flow effects, system understanding, and publication. We continued efforts to assimilate geophysical logging and 3D ERT characterization data into our site wide geophysical model, and have now implemented a new strategy for this activity to bypass an approach that was found unworkable. An important focus of CY 2010 activities has been infrastructure modification to the IFRC site to eliminate vertical well bore flows in the fully screened wells. The mitigation procedure was carefully evaluated and is now being implementated. A new experimental campaign is planned for early spring 2011 that will utilize the modified well-field for a U reactive transport experiment in the upper aquifer zone. Preliminary geophysical monitoring experiments of rainwater recharge in the vadose zone have been initiated with promising results, and a controlled infiltration experiment to evaluate U mobilization from the vadose zone is now under planning for the September 2011. The increasingly comprehensive field experimental results, along with the field and laboratory characterization, are leading to a new conceptual model of U(VI) flow and transport in the IFRC footprint and the 300 Area in general, and insights on the microbiological community and associated biogeochemical processes.

  18. Multi-Scale Mass Transfer Processes Controlling Natural Attenuation and Engineered Remediation: An IFRC Focused on Hanford’s 300 Area Uranium Plume

    SciTech Connect (OSTI)

    Zachara, John M.; Bjornstad, Bruce N.; Christensen, John N.; Conrad, Mark E.; Fredrickson, Jim K.; Freshley, Mark D.; Haggerty, Roy; Hammon, Glenn; Kent, Douglas B.; Konopka, Allan; Lichtner, Peter C.; Liu, Chongxuan; McKinley, James P.; Murray, Christopher J.; Rockhold, Mark L.; Rubin, Yoram; Vermeul, Vincent R.; Versteeg, Roelof J.; Ward, Anderson L.; Zheng, Chunmiao

    2010-02-01

    The Integrated Field-Scale Subsurface Research Challenge (IFRC) at the Hanford Site 300 Area uranium (U) plume addresses multi-scale mass transfer processes in a complex hydrogeologic setting where groundwater and riverwater interact. A series of forefront science questions on mass transfer are posed for research which relate to the effect of spatial heterogeneities; the importance of scale; coupled interactions between biogeochemical, hydrologic, and mass transfer processes; and measurements and approaches needed to characterize and model a mass-transfer dominated system. The project was initiated in February 2007, with CY 2007 and CY 2008 progress summarized in preceding reports. The site has 35 instrumented wells, and an extensive monitoring system. It includes a deep borehole for microbiologic and biogeochemical research that sampled the entire thickness of the unconfined 300 A aquifer. Significant, impactful progress has been made in CY 2009 with completion of extensive laboratory measurements on field sediments, field hydrologic and geophysical characterization, four field experiments, and modeling. The laboratory characterization results are being subjected to geostatistical analyses to develop spatial heterogeneity models of U concentration and chemical, physical, and hydrologic properties needed for reactive transport modeling. The field experiments focused on: (1) physical characterization of the groundwater flow field during a period of stable hydrologic conditions in early spring, (2) comprehensive groundwater monitoring during spring to characterize the release of U(VI) from the lower vadose zone to the aquifer during water table rise and fall, (3) dynamic geophysical monitoring of salt-plume migration during summer, and (4) a U reactive tracer experiment (desorption) during the fall. Geophysical characterization of the well field was completed using the down-well Electrical Resistance Tomography (ERT) array, with results subjected to robust, geostatistically constrained inversion analyses. These measurements along with hydrologic characterization have yielded 3D distributions of hydraulic properties that have been incorporated into an updated and increasingly robust hydrologic model. Based on significant findings from the microbiologic characterization of deep borehole sediments in CY 2008, down-hole biogeochemistry studies were initiated where colonization substrates and spatially discrete water and gas samplers were deployed to select wells. The increasingly comprehensive field experimental results, along with the field and laboratory characterization, are leading to a new conceptual model of U(VI) flow and transport in the IFRC footprint and the 300 Area in general, and insights on the microbiological community and associated biogeochemical processes. A significant issue related to vertical flow in the IFRC wells was identified and evaluated during the spring and fall field experimental campaigns. Both upward and downward flows were observed in response to dynamic Columbia River stage. The vertical flows are caused by the interaction of pressure gradients with our heterogeneous hydraulic conductivity field. These impacts are being evaluated with additional modeling and field activities to facilitate interpretation and mitigation. The project moves into CY 2010 with ambitious plans for a drilling additional wells for the IFRC well field, additional experiments, and modeling. This research is part of the ERSP Hanford IFRC at Pacific Northwest National Laboratory.

  19. Did a gamma-ray burst initiate the late Ordovician mass extinction?

    E-Print Network [OSTI]

    Melott, Adrian L.; Lieberman, Bruce S.; Laird, C. M.; Martin, Larry D.; Medvedev, Mikhail V.; Thomas, Brian C.; Cannizzo, J. K.; Gehrels, N.; Jackman, C. H.

    2004-01-01

    Gamma-ray bursts (GRBs) produce a flux of radiation detectable across the observable Universe. A GRB within our own galaxy could do considerable damage to the Earth's biosphere; rate estimates suggest that a dangerously near GRB should occur...

  20. X-ray outbursts of ESO 243-49 HLX-1: comparison with Galactic low-mass X-ray binary transients

    E-Print Network [OSTI]

    Yan, Zhen; Soria, Roberto; Altamirano, Diego; Yu, Wenfei

    2015-01-01

    We studied the outburst properties of the hyper-luminous X-ray source ESO 243-49 HLX-1, using the full set of Swift monitoring observations. We quantified the increase in the waiting time, recurrence time and e-folding rise timescale along the outburst sequence, and the corresponding decrease in outburst duration, total radiated energy, and e-folding decay timescale, which confirms previous findings. HLX-1 spends less and less time in outburst and more and more time in quiescence, but its peak luminosity remains approximately constant. We compared the HLX-1 outburst properties with those of bright Galactic low-mass X-ray binary transients (LMXBTs). Our spectral analysis strengthens the similarity between state transitions in HLX-1 and those in Galactic LMXBTs. We also found that HLX-1 follows the nearly linear correlations between the hard-to-soft state transition luminosity and the peak luminosity, and between the rate of change of X-ray luminosity during the rise phase and the peak luminosity, which indicat...

  1. Discovery of slow X-ray pulsations in the high-mass X-ray binary 4U 2206+54

    E-Print Network [OSTI]

    P. Reig; J. M Torrejon; I. Negueruela; P. Blay; M. Ribo; J. Wilms

    2008-12-12

    The source 4U 2206+54 is one of the most enigmatic high-mass X-ray binaries. In spite of intensive searches, X-ray pulsations have not been detected in the time range 0.001-1000 s. A cyclotron line at ~30 keV has been suggested by various authors but never detected with significance. The stellar wind of the optical companion is abnormally slow. The orbital period, initially reported to be 9.6 days, disappeared and a new periodicity of 19.25 days emerged. Our new long and uninterrupted RXTE observations allow us to search for long (~1 hr) pulsations for the first time. We have discovered 5560-s pulsations in the light curve of 4U 2206+54. Initially detected in RXTE data, these pulsations are also present in INTEGRAL and EXOSAT observations. The average X-ray luminosity in the energy range 2-10 keV is 1.5 x 10^{35} erg s^{-1} with a ratio Fmax/Fmin ~ 5. This ratio implies an eccentricity of ~0.4, somewhat higher than previously suggested. The source also shows a soft excess at low energies. If the soft excess is modelled with a blackbody component, then the size and temperature of the emitting region agrees with its interpretation in terms of a hot spot on the neutron star surface. The source displays variability on time scales of days, presumably due to changes in the mass accretion rate as the neutron star moves around the optical companion in a moderately eccentric orbit.

  2. A Remarkable Low-Mass X-ray Binary within 0.1 pc of the Galactic Center

    E-Print Network [OSTI]

    M. P. Muno; J. R. Lu; F. K. Baganoff; W. N. Brandt; G. P. Garmire; A. M. Ghez; S. D. Hornstein; M. R. Morris

    2005-03-26

    Recent X-ray and radio observations have identified a transient low-mass X-ray binary (LMXB) located only 0.1 pc in projection from the Galactic center, CXOGC J174540.0-290031. In this paper, we report the detailed analysis of X-ray and infrared observations of the transient and its surroundings. Chandra bservations detect the source at a flux of F_X = 2e-12 erg cm^-2 s^-1 (2-8 keV). After accounting for absorption both in the interstellar medium and in material local to the source, the implied luminosity of the source is only L_X = 4e34 erg/s (2-8 keV; D=8 kpc). However, the diffuse X-ray emission near the source also brightened by a factor of 2. The enhanced diffuse X-ray emission lies on top of a known ridge of dust and ionized gas that is visible infrared images. We interpret the X-ray emission as scattered flux from the outburst, and determine that the peak luminosity of CXOGC J174540.0-290031 was >2e36 erg/s. We suggest that the relatively small observed flux results from the fact that the system is observed nearly edge-on, so that the accretion disk intercepts most of the flux emitted along our line of sight. We compare the inferred peak X-ray luminosity to that of the radio jet. The ratio of the X-ray to radio luminosities, L_X/L_R 1e5). This is probably because the jets are radiating with unusually high efficiency at the point where they impact the surrounding interstellar medium. This hypothesis is supported by a comparison with mid-infrared images of the surrounding dust. Finally, we find that the minimum power required to produce the jet, L_jet~1e37 erg/s, is comparable to the inferred peak X-ray luminosity. This is the most direct evidence yet obtained that LMXBs accreting at low rates release about half of their energy as jets.

  3. Spin and Spectral Variations of Peculiar High-Mass X-ray Binary 4U 2206+54

    E-Print Network [OSTI]

    Wang, Wei

    2013-01-01

    Spin properties and spectral variations of high mass X-ray binary 4U 2206+54 are studied with long-term hard X-ray monitoring observations by INTEGRAL. A long-period X-ray pulsar of P_spin\\sim 5558 s has been identified in 4U 2206+54. The spin evolution of the neutron star in 4U 2206+54 is detected with the INTEGRAL/IBIS data. From 2005 to 2011, the spin period of the neutron star in 4U 2206+54 varies from \\sim 5558 s to 5588 s. The average spin-down rate in the last 20 years is derived as \\sim 5\\times 10^{-7} s s^{-1}. 4U 2206+54 is a variable source with luminosities of \\sim 10^{35} - 10^{36} erg s^{-1} in the range of 3 -- 100 keV. Its spectrum can be described by an absorbed power-law model with exponential rolloff. The hydrogen column density and photon index show the anti-correlations with hard X-ray luminosity: low column density and small photon index at maximum of luminosity. This spectral variation pattern suggests that 4U 2206+54 would be a highly obscured binary system. Furthermore, the possible c...

  4. On the outburst light curves of soft X-Ray transients as response of the accretion disk to mass deposition

    E-Print Network [OSTI]

    Unal Ertan; M. Ali Alpar

    1998-05-13

    We note that the solution of accretion disk dynamics for an initial delta-function mass distribution gives a light curve that fits both the rise and the decay pattern of the outburst light curves of black-hole soft X-ray transients (BSXTs) until the onset of the first mini outburst quite well. The Green's function solution of Lynden-Bell & Pringle (1974) is employed for two differenttime-independent viscosity laws to calculate the expected count rates of X-ray photons in the Ginga energy bands as a function of time. For both models basic characteristics of the outburst light curves of two typical sources GS 2000+25 and GS/GRS 1124-68 are reproduced together with plausible values of the thin disk parameter $\\alpha$ and the recurrence times. This agreement with the outburst light curves and the source properties during quiescence support the idea of mass accumulation and the sporadic release of accumulated mass at the outer disk.

  5. Seismic viscoelastic attenuation Submitted to

    E-Print Network [OSTI]

    Cormier, Vernon F.

    Seismic viscoelastic attenuation Submitted to: Encyclopedia of Solid Earth Geophysics Harsh Gupta-3046 USA E-mail: vernon.cormier@uconn.edu Tel: 860-486-3547 Fax: 860-486-3346 #12;SEISMIC VISCOELASTIC ATTENUATION Synonyms Seismic intrinsic attenuation Definitions Linear viscoelastic attenuation. The loss

  6. Cyclotron line and wind studies of galactic high mass X- ray binaries

    E-Print Network [OSTI]

    Suchy, Slawomir

    2011-01-01

    of a low mass star, where the fusion process has stopped andhydrogen of the fusion process is depleted, the star reacheshydrogen fusion process. In binary systems, where one star

  7. Mass fractal characteristics of silica sonogels as determined by small-angle x-ray scattering and nitrogen adsorption

    SciTech Connect (OSTI)

    Donatti, D.A.; Vollet, D.R.; Ibanez Ruiz, A.; Mesquita, A.; Silva, T.F.P. [Unesp-Universidade Estadual Paulista, IGCE, Departamento de Fisica, P.O. Box 178 CEP, 13500-970 Rio Claro, Sao Paulo (Brazil)

    2005-01-01

    A sample series of silica sonogels was prepared using different water-tetraethoxysilane molar ratio (r{sub w}) in the gelation step of the process in order to obtain aerogels with different bulk densities after the supercritical drying. The samples were analyzed by means of small-angle x-ray-scattering (SAXS) and nitrogen-adsorption techniques. Wet sonogels exhibit mass fractal structure with fractal dimension D increasing from {approx}2.1 to {approx}2.4 and mass-fractal correlation length {xi} diminishing from {approx}13 nm to {approx}2 nm, as r{sub w} is changed in the nominal range from 66 to 6. The process of obtaining aerogels from sonogels and heat treatment at 500 deg. C, in general, increases the mass-fractal dimension D, diminishes the characteristic length {xi} of the fractal structure, and shortens the fractal range at the micropore side for the formation of a secondary structured particle, apparently evolved from the original wet structure at a high resolution level. The overall mass-fractal dimension D of aerogels was evaluated as {approx}2.4 and {approx}2.5, as determined from SAXS and from pore-size distribution by nitrogen adsorption, respectively. The fine structure of the 'secondary particle' developed in the obtaining of aerogels could be described as a surface-mass fractal, with the correlated surface and mass-fractal dimensions decreasing from {approx}2.4 to {approx}2.0 and from {approx}2.7 to {approx}2.5, respectively, as the aerogel bulk density increases from 0.25 (r{sub w}=66) up to 0.91 g/cm{sup 3} (r{sub w}=6)

  8. A new Comptonization model for low-magnetized accreting neutron stars in low mass X-ray binaries

    E-Print Network [OSTI]

    R. Farinelli; L. Titarchuk; A. Paizis; F. Frontera

    2008-02-19

    We developed a new model for the X-ray spectral fitting \\xspec package which takes into account the effects of both thermal and dynamical (i.e. bulk) Comptonization. The model consists of two components: one is the direct blackbody-like emission due to seed photons which are not subjected to effective Compton scattering, while the other one is a convolution of the Green's function of the energy operator with a blackbody-like seed photon spectrum. When combined thermal and bulk effects are considered, the analytic form of the Green's function may be obtained as a solution of the diffusion Comptonization equation. Using data from the BeppoSAX, INTEGRAL and RXTE satellites, we test our model on the spectra of a sample of six persistently low magnetic field bright neutron star Low Mass X-ray Binaries, covering three different spectral states. Particular attention is given to the transient powerlaw-like hard X-ray (> 30 keV) tails that we interpret in the framework of the bulk motion Comptonization process. We show that the values of the best-fit delta-parameter, which represents the importance of bulk with respect to thermal Comptonization, can be physically meaningful and can at least qualitatively describe the physical conditions of the environment in the innermost part of the system. Moreover, we show that in fitting the thermal Comptonization spectra to the X-ray spectra of these systems, the best-fit parameters of our model are in excellent agreement with those of COMPTT, a broadly used and well established XSPEC model.

  9. On the Contribution of Gamma Ray Bursts to the Galactic Inventory of Some Intermediate Mass Nuclei

    E-Print Network [OSTI]

    Jason Pruet; Rebecca Surman; Gail C. McLaughlin

    2003-09-24

    Light curves from a growing number of Gamma Ray Bursts (GRBs) indicate that GRBs copiously produce radioactive Ni moving outward at fractions of the speed of light. We calculate nuclear abundances of elements accompanying the outflowing Ni under the assumption that this Ni originates from a wind blown off of a viscous accretion disk. We also show that GRB's likely contribute appreciably to the galactic inventory of 42Ca, 45Sc, 46Ti, 49Ti, 63Cu, and may be a principal site for the production of 64Zn.

  10. Review of low-mass X-ray binaries near the Galactic center

    E-Print Network [OSTI]

    Lutovinov, A; Molkov, S; Sunyaev, R A

    2003-01-01

    Results of observations of several LMXBs in the Galactic center region carried out with the ART-P telescope on board \\Granat observatory are briefly reviewed. More than dozen sources were revealed in this region during five series of observations which were performed with the ART-P telescope in 1990-1992. The investigation of the spectral evolution of persistent emission of two X-ray bursters GX3+1 and KS1731-260, discussion of QPO and spectral variations detected from the very bright Z-source GX5-1 and studying the pulse profile changes of the pulsar GX1+4 were carried out.

  11. Lithium production on a low-mass secondary in a black hole soft X-ray transient

    E-Print Network [OSTI]

    Shin-ichiro Fujimoto; Ryuichi Matsuba; Kenzo Arai

    2007-10-10

    We examine production of Li on the surface of a low-mass secondary in a black hole soft X-ray transient (BHSXT) through the spallation of CNO nuclei by neutrons which are ejected from a hot (> 10 MeV) advection-dominated accretion flow (ADAF) around the black hole. Using updated binary parameters, cross sections of neutron-induced spallation reactions, and mass accretion rates in ADAF derived from the spectrum fitting of multi-wavelength observations of quiescent BHSXTs, we obtain the equilibrium abundances of Li by equating the production rate of Li and the mass transfer rate through accretion to the black hole. The resulting abundances are found to be in good agreement with the observed values in seven BHSXTs. We note that the abundances vary in a timescale longer than a few months in our model. Moreover, the isotopic ratio Li6/Li7 is calculated to be about 0.7--0.8 on the secondaries, which is much higher than the ratio measured in meteorites. Detection of such a high value is favorable to the production of Li via spallation and the existence of a hot accretion flow, rather than an accretion disk corona system in quiescent BHSXT.

  12. Cosmic ray primary mass composition above the knee: deduction from lateral distribution of electrons

    E-Print Network [OSTI]

    R. I. Raikin; A. A. Lagutin; A. V. Yushkov

    2008-03-18

    Influence of shower fluctuations on the shape of lateral distribution of electrons in EAS of fixed size measured by scintillation counters is analyzed in framework of scaling formalism. Correction factors for the mean square radius of electrons are calculated for the experimental conditions of KASCADE array. Possible improvement of the primary mass discrimination by analysis of lateral distribution of EAS electrons is discussed in detail.

  13. The X-Ray Luminosity--Mass Relation for Local Clusters of Galaxies

    E-Print Network [OSTI]

    R. Stanek; A. E. Evrard; H. Böhringer; P. Schuecker; B. Nord

    2006-05-30

    We investigate the relationship between soft \\xray luminosity and mass for low redshift clusters of galaxies by comparing observed number counts to expectations of $\\Lambda$CDM cosmologies. We use a three-parameter model for the conditional probability of luminosity given mass and epoch, described as a log-normal distribution of fixed width centered on a power-law scaling relation, $L \\spropto M^p\\rhoc^s(z)$. We use an ensemble of simulated clusters to argue that the observed, intrinsic variance in the temperature--luminosity relation is directly indicative of mass--luminosity variance, and derive $\\sigm \\se 0.43 \\pm 0.06$ from HIFLUGCS data. Adding this to the likelihood analysis results in best-fit estimates $p \\se 1.59 \\pm 0.05$, $\\lnlf \\se 1.34 \\pm 0.09$, and $\\sigm \\se 0.37 \\pm 0.05$ for self-similar redshift evolution in a concordance ($\\Omega_m \\se 0.3$, $\\Omega_\\Lambda \\se 0.7$, $\\sigma_8 \\se0.9$) universe. We show that the present-epoch intercept is very sensitive to power spectrum normalization, $\\lnlf \\spropto \\sigate^{-4}$, and the slope is weakly sensitive to the matter density, $p \\spropto \\Omega_m^{1/2}$. The intercept derived here is dimmer by a factor 2, and slope slightly steeper, than the L-M relation published using hydrostatic mass estimates of the HIFLUGCS sample. We show that this discrepancy is largely due to Malmquist bias of the \\xray\\ flux-limited sample. In light of new WMAP constraints, we discuss the interplay between parameters and sources of systematic error, and offer a compromise model with $\\Omega_m \\se 0.24$, $\\sigma_8 \\se 0.85$, and somewhat lower scatter $\\sigm \\se 0.25$, in which hydrostatic mass estimates remain accurate to $\\ssim 15%$. We stress the need for independent calibration of the L-M relation via weak gravitational lensing.

  14. SHORT GAMMA-RAY BURSTS: THE MASS OF THE ACCRETION DISK AND THE INITIAL RADIUS OF THE OUTFLOW

    SciTech Connect (OSTI)

    Fan Yizhong; Wei Daming, E-mail: yzfan@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2011-09-20

    In this work, we estimate the accretion-disk mass in the specific scenario of binary-neutron-star merger with current observational data. Assuming that the outflows of short gamma-ray bursts (GRBs) are driven via neutrino-antineutrino annihilation we estimate the disk mass of about half of short bursts in the sample to be {approx}0.01-0.1 M{sub sun}, in agreement with that obtained in the numerical simulations. Massive disks ({approx}several 0.1 M{sub sun}) found in some other short GRBs may point to the more efficient magnetic process of extracting energy or the neutron star and black hole binary progenitor. Our results suggest that some short bursts may be really due to the coalescence of double neutron stars and are promising gravitational wave radiation sources. For future short GRBs with simultaneous gravitational-wave detections, the disk mass may be reliably inferred and the validity of our approach will be tested. We also propose a method to constrain the initial radius of a baryonic outflow where it is launched (R{sub 0}) without the need of identifying an ideal thermal spectrum component. We then apply it to GRB 090510 and get R{sub 0} {approx}< 6.5 x 10{sup 6}({Gamma}{sub ph}/2000){sup -4} cm, suggesting that the central engine is a black hole with a mass <22 M{sub sun}({Gamma}{sub ph}/2000){sup -4}, where {Gamma}{sub ph} is the bulk Lorentz factor of the outflow at the photospheric radius.

  15. Mass fractal characteristics of wet sonogels as determined by small-angle x-ray scattering and differential scanning calorimetry

    SciTech Connect (OSTI)

    Vollet, D. R.; Donatti, D. A.; Ibanez Ruiz, A.; Gatto, F. R. [Departamento de Fisica, Unesp-Univerisdade Estadual Paulista, IGCE, P.O. Box 178 CEP 13500-970 Rio Claro, SP (Brazil)

    2006-07-01

    Low density silica sonogels were prepared from acid sonohydrolysis of tetraethoxysilane. Wet gels were studied by small-angle x-ray scattering (SAXS) and differential scanning calorimetry (DSC). The DSC tests were carried out under a heating rate of 2 deg. C/min from -120 deg. C up to 30 deg. C. Aerogels were obtained by CO{sub 2} supercritical extraction and characterized by nitrogen adsorption and SAXS. The DSC thermogram displays two distinct endothermic peaks. The first, a broad peak extending from about -80 deg. C up to practically 0 deg. C, was associated to the melting of ice nanocrystals with a crystal size distribution with 'pore' diameter ranging from 1 or 2 nm up to about 60 nm, as estimated from Thomson's equation. The second, a sharp peak with onset temperature close to 0 deg. C, was attributed to the melting of macroscopic crystals. The DSC incremental 'nanopore' volume distribution is in reasonable agreement with the incremental pore volume distribution of the aerogel as determined from nitrogen adsorption. No macroporosity was detected by nitrogen adsorption, probably because the adsorption method applies stress on the sample during measurement, leading to a underestimation of pore volume, or because often positive curvature of the solid surface is in aerogels, making the nitrogen condensation more difficult. According to the SAXS results, the solid network of the wet gels behaves as a mass fractal structure with mass fractal dimension D=2.20{+-}0.01 in a characteristic length scale below {xi}=7.9{+-}0.1 nm. The mass fractal characteristics of the wet gels have also been probed from DSC data by means of an earlier applied modeling for generation of a mass fractal from the incremental ''pore'' volume distribution curves. The results are shown to be in interesting agreement with the results from SAXS.

  16. SN 2010jl: Optical to hard X-ray observations reveal an explosion embedded in a ten solar mass cocoon

    SciTech Connect (OSTI)

    Ofek, Eran O.; Gal-Yam, Avishay; Arcavi, Iair [Benoziyo Center for Astrophysics, Weizmann Institute of Science, 76100 Rehovot (Israel); Zoglauer, Andreas; Boggs, Steven E.; Barriére, Nicolas M. [Space Sciences Laboratory, Department of Physics, University of California, 7 Gauss Way, Berkeley, CA 94720 (United States); Reynolds, Stephen P. [Department of Physics, North Carolina State University, Raleigh, NC 27695-8202 (United States); Fryer, Chris L.; Even, Wesley [CCS Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Harrison, Fiona A.; Kulkarni, Shrinivas R.; Bellm, Eric; Grefenstette, Brian [Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Cenko, S. Bradley; Bloom, Joshua S.; Filippenko, Alexei V. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States); Christensen, Finn [DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Craig, William W.; Hailey, Charles J. [Columbia Astrophysics Laboratory, 538 West 120th Street, New York, NY 10027 (United States); Laher, Russ [Spitzer Science Center, MS 314-6, California Institute of Technology, Pasadena, CA 91125 (United States); and others

    2014-01-20

    Some supernovae (SNe) may be powered by the interaction of the SN ejecta with a large amount of circumstellar matter (CSM). However, quantitative estimates of the CSM mass around such SNe are missing when the CSM material is optically thick. Specifically, current estimators are sensitive to uncertainties regarding the CSM density profile and the ejecta velocity. Here we outline a method to measure the mass of the optically thick CSM around such SNe. We present new visible-light and X-ray observations of SN 2010jl (PTF 10aaxf), including the first detection of an SN in the hard X-ray band using NuSTAR. The total radiated luminosity of SN 2010jl is extreme—at least 9 × 10{sup 50} erg. By modeling the visible-light data, we robustly show that the mass of the circumstellar material within ?10{sup 16} cm of the progenitor of SN 2010jl was in excess of 10 M {sub ?}. This mass was likely ejected tens of years prior to the SN explosion. Our modeling suggests that the shock velocity during shock breakout was ?6000 km s{sup –1}, decelerating to ?2600 km s{sup –1} about 2 yr after maximum light. Furthermore, our late-time NuSTAR and XMM spectra of the SN presumably provide the first direct measurement of SN shock velocity 2 yr after the SN maximum light—measured to be in the range of 2000-4500 km s{sup –1} if the ions and electrons are in equilibrium, and ? 2000 km s{sup –1} if they are not in equilibrium. This measurement is in agreement with the shock velocity predicted by our modeling of the visible-light data. Our observations also show that the average radial density distribution of the CSM roughly follows an r {sup –2} law. A possible explanation for the ? 10 M {sub ?} of CSM and the wind-like profile is that they are the result of multiple pulsational pair instability events prior to the SN explosion, separated from each other by years.

  17. Methods of Determination of the Energy and Mass of Primary Cosmic Ray Particles at Extensive Air Shower Energies

    E-Print Network [OSTI]

    Karl-Heinz Kampert

    2001-01-29

    Measurements of cosmic ray particles at energies above E = 5 x 10^{14} eV are performed by large area ground based air shower experiments. Only they provide the collection power required for obtaining sufficient statistics at the low flux levels involved. In this review we briefly outline the physics and astrophysics interests of such measurements and discuss in more detail various experimental techniques applied for reconstructing the energy and mass of the primary particles. These include surface arrays of particle detectors as well as observations of Cherenkov- and of fluorescence light. A large variety of air shower observables is then reconstructed from such data and used to infer the properties of the primary particles via comparisons to air shower simulations. Advantages, limitations, and systematic uncertainties of different approaches will be critically discussed.

  18. Superfluid effects on gauging core temperatures of neutron stars in low-mass X-ray binaries

    E-Print Network [OSTI]

    Wynn C. G. Ho

    2011-10-06

    Neutron stars accreting matter from low-mass binary companions are observed to undergo bursts of X-rays due to the thermonuclear explosion of material on the neutron star surface. We use recent results on superfluid and superconducting properties to show that the core temperature in these neutron stars may not be uniquely determined for a range of observed accretion rates. The degeneracy in inferred core temperatures could contribute to explaining the difference between neutron stars which have very short recurrence times between multiple bursts and those which have long recurrence times between bursts: short bursting sources have higher temperatures and normal neutrons in the stellar core, while long bursting sources have lower temperatures and superfluid neutrons. If correct, measurements of the lowest luminosity from among the short bursting sources and highest luminosity from among the long bursting sources can be used to constrain the critical temperature for the onset of neutron superfluidity.

  19. Herschel OBSERVATIONS OF DUST AROUND THE HIGH-MASS X-RAY BINARY GX 301-2

    SciTech Connect (OSTI)

    Servillat, M. [Laboratoire Univers et Théories (CNRS/INSU, Observatoire de Paris, Université Paris Diderot), 5 place Jules Janssen, F-92190 Meudon (France); Coleiro, A.; Chaty, S. [Laboratoire AIM (CEA/Irfu/SAp, CNRS/INSU, Universit Paris Diderot), CEA Saclay, Bat. 709, F-91191 Gif-sur-Yvette (France); Rahoui, F. [Harvard University, Department of Astronomy, 60 Garden Street, Cambridge, MA 02138 (United States); Zurita Heras, J. A., E-mail: mathieu.servillat@obspm.fr [AstroParticule et Cosmologie (Université Paris Diderot, CNRS/IN2P3, CEA/DSM, Observatoire de Paris, Sorbonne Paris Cité), 10 rue Alice Domon et Léonie Duquet, F-75205 Paris Cedex 13 (France)

    2014-12-20

    We aim at characterizing the structure of the gas and dust around the high-mass X-ray binary GX 301-2, a highly obscured X-ray binary hosting a hypergiant (HG) star and a neutron star, in order to better constrain its evolution. We used Herschel PACS to observe GX 301-2 in the far infrared and completed the spectral energy distribution of the source using published data or catalogs from the optical to the radio range (0.4 to 4 × 10{sup 4} ?m). GX 301-2 is detected for the first time at 70 and 100 ?m. We fitted different models of circumstellar (CS) environments to the data. All tested models are statistically acceptable, and consistent with an HG star at ?3 kpc. We found that the addition of a free-free emission component from the strong stellar wind is required and could dominate the far-infrared flux. Through comparisons with similar systems and discussion on the estimated model parameters, we favor a disk-like CS environment of ?8 AU that would enshroud the binary system. The temperature goes down to ?200 K at the edge of the disk, allowing for dust formation. This disk is probably a rimmed viscous disk with an inner rim at the temperature of the dust sublimation temperature (?1500 K). The similarities between the HG GX 301-2, B[e] supergiants, and the highly obscured X-ray binaries (particularly IGR J16318-4848) are strengthened. GX 301-2 might represent a transition stage in the evolution of massive stars in binary systems, connecting supergiant B[e] systems to luminous blue variables.

  20. Sgr A* and its Environment: Low Mass Star Formation, the Origin of X-ray Gas and Collimated Outflow

    E-Print Network [OSTI]

    Yusef-Zadeh, F; Schödel, R; Roberts, D A; Cotton, W; Bushouse, H; Arendt, R; Royster, M

    2016-01-01

    We present high-resolution multiwavelength radio continuum images of the region within 150$"$ of Sgr A*, revealing a number of new extended features and stellar sources in this region. First, we detect a continuous 2" east-west ridge of radio emission, linking Sgr A* and a cluster of stars associated with IRS 13N and IRS 13E. The ridge suggests that an outflow of east-west blob-like structures is emerging from Sgr A*. We also find arc-like features within the ridge with morphologies suggestive of photoevaporative protoplanetary disks. We use near-IR fluxes to show that the emission has similar characteristics to those of a protoplanetary disk irradiated by the intense radiation field at the Galactic center. This suggests that star formation has taken place within the S cluster 2$"$ from Sgr A*. We suggest that the diffuse X-ray emission associated with Sgr A* is due to an expanding hot wind produced by the mass loss from B-type main sequence stars, and/or the disks of photoevaporation of low mass YSOs at a ra...

  1. The galaxy cluster X-ray luminosity--gravitational mass relation in the light of the WMAP 3rd year data

    E-Print Network [OSTI]

    Thomas H. Reiprich

    2006-05-22

    The 3rd year WMAP results mark a shift in best fit values of cosmological parameters compared to the 1st year data and the concordance cosmological model. We test the consistency of the new results with previous constraints on cosmological parameters from the HIFLUGCS galaxy cluster sample and the impact of this shift on the X-ray luminosity-gravitational mass relation. The measured X-ray luminosity function combined with the observed luminosity-mass relation are compared to mass functions predicted for given cosmological parameter values. The luminosity function and luminosity-mass relation derived previously from HIFLUGCS are in perfect agreement with mass functions predicted using the best fit parameter values from the 3rd year WMAP data (OmegaM=0.238, sigma8=0.74) and inconsistent with the concordance cosmological model (OmegaM=0.3, sigma8=0.9), assuming a flat Universe. Trying to force consistency with the concordance model requires artificially decreasing the normalization of the luminosity-mass relation by a factor of 2. The shift in best fit values for OmegaM and sigma8 has a significant impact on predictions of cluster abundances. The new WMAP results are now in perfect agreement with previous results on the OmegaM-sigma8 relation determined from the mass function of HIFLUGCS clusters and other X-ray cluster samples (the ``low cluster normalization''). We conclude that - unless the true values of OmegaM and sigma8 differ significantly from the 3rd year WMAP results - the luminosity-mass relation is well described by their previous determination from X-ray observations of clusters, with a conservative upper limit on the bias factor of 1.5. These conclusions are currently being tested in a complete follow-up program of all HIFLUGCS clusters with Chandra and XMM-Newton.

  2. ASTRO-H White Paper - Low-mass X-ray Binaries

    E-Print Network [OSTI]

    Done, C; Cackett, E; Herder, J W den; Dotani, T; Enoto, T; Ferrigno, C; Kallman, T; Kohmura, T; Laurent, P; Miller, J; Mineshige, S; Mori, H; Nakazawa, K; Paerels, F; Sakurai, S; Soong, Y; Sugita, S; Takahashi, H; Tamagawa, T; Tanaka, Y; Terada, Y; Uno, S

    2014-01-01

    There is still 10-20% uncertainty on the neutron star (NS) mass-radius relation. These uncertainties could be reduced by an order of magnitude through an unambiguous measure of M/R from the surface redshift of a narrow line, greatly constraining the Equation of State for ultra-dense material. It is possible that the SXS on ASTRO-H can detect this from an accreting neutron star with low surface velocity in the line of sight i.e. either low inclination or low spin. Currently there is only one known low inclination LMXB, Ser X-1, and one known slow spin LMXB, J17480-2446 in Terzan 5. Ser X-1 is a persistent source which is always in the soft state (banana branch), where the accreting material should form a equatorial belt around the neutron star. A pole-on view should then allow the NS surface to be seen directly. A 100 ks observation should allow us to measure M/R if there are any heavy elements in the photosphere at the poles. Conversely, J17480-2446 in Terzan 5 is a transient accretion powered millisecond pul...

  3. CONSTRAINTS ON POROSITY AND MASS LOSS IN O-STAR WINDS FROM THE MODELING OF X-RAY EMISSION LINE PROFILE SHAPES

    SciTech Connect (OSTI)

    Leutenegger, Maurice A.; Sundqvist, Jon O.; Owocki, Stanley P.

    2013-06-10

    We fit X-ray emission line profiles in high resolution XMM-Newton and Chandra grating spectra of the early O supergiant {zeta} Pup with models that include the effects of porosity in the stellar wind. We explore the effects of porosity due to both spherical and flattened clumps. We find that porosity models with flattened clumps oriented parallel to the photosphere provide poor fits to observed line shapes. However, porosity models with isotropic clumps can provide acceptable fits to observed line shapes, but only if the porosity effect is moderate. We quantify the degeneracy between porosity effects from isotropic clumps and the mass-loss rate inferred from the X-ray line shapes, and we show that only modest increases in the mass-loss rate ({approx}< 40%) are allowed if moderate porosity effects (h{sub {infinity}} {approx}< R{sub *}) are assumed to be important. Large porosity lengths, and thus strong porosity effects, are ruled out regardless of assumptions about clump shape. Thus, X-ray mass-loss rate estimates are relatively insensitive to both optically thin and optically thick clumping. This supports the use of X-ray spectroscopy as a mass-loss rate calibration for bright, nearby O stars.

  4. THE FADING OF TWO TRANSIENT ULTRALUMINOUS X-RAY SOURCES TO BELOW THE STELLAR MASS EDDINGTON LIMIT

    SciTech Connect (OSTI)

    Burke, Mark J.; Raychaudhury, Somak [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Kraft, Ralph P.; Forman, William R.; Jones, Christine; Murray, Stephen S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Soria, Roberto [International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia); Maccarone, Thomas J. [Astronomy and Astrophysics Group, Texas Tech University, Lubbock, TX 79409-105 (United States); Sivakoff, Gregory R. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2E1 (Canada); Birkinshaw, Mark; Worrall, Diana M. [HH Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Brassington, Nicola J.; Hardcastle, Martin J., E-mail: mburke@star.sr.bham.ac.uk [School of Physics, Astronomy, and Mathematics, University of Hertfordshire, Hatfield, AL10 9AB (United Kingdom)

    2013-09-20

    We report new detections of the two transient ultraluminous X-ray sources (ULXs) in NGC 5128 from an ongoing series of Chandra observations. Both sources have previously been observed L{sub x} (2-3) × ?10{sup 39} erg s{sup –1}, at the lower end of the ULX luminosity range. The new observations allow us to study these sources in the luminosity regime frequented by the Galactic black hole X-ray binaries (BH XBs). We present the recent lightcurves of both ULXs. 1RXH J132519.8-430312 (ULX1) was observed at L{sub x} ? 1 × 10{sup 38} erg s{sup –1}, while CXOU J132518.2-430304 (ULX2) declined to L{sub x} ? 2 × 10{sup 37} erg s{sup –1} and then lingered at this luminosity for hundreds of days. We show that a reasonable upper limit for both duty cycles is 0.2, with a lower limit of 0.12 for ULX2. This duty cycle is larger than anticipated for transient ULXs in old stellar populations. By fitting simple spectral models in an observation with ?50 counts we recover properties consistent with Galactic BH XBs, but inconclusive as to the spectral state. We utilize quantile analyses to demonstrate that the spectra are generally soft, and that in one observation the spectrum of ULX2 is inconsistent with a canonical hard state at >95% confidence. This is contrary to what would be expected of an accreting intermediate mass black hole primary, which we would expect to be in the hard state at these luminosities. We discuss the paucity of transient ULXs discovered in early-type galaxies and excogitate explanations. We suggest that the number of transient ULXs scales with the giant and sub-giant populations, rather than the total number of XBs.

  5. Optical spectroscopy of the high-mass gamma-ray binary 1FGL J1018.6-5856: A probable neutron star primary

    E-Print Network [OSTI]

    Strader, Jay; Cheung, C C; Salinas, Ricardo; Peacock, Mark

    2015-01-01

    We present medium-resolution optical spectroscopy with the SOAR telescope of the O star secondary of the high-mass gamma-ray binary 1FGL J1018.6-5856 to help determine whether the primary is a neutron star or black hole. We find that the secondary has a low radial velocity semi-amplitude of 11-12 km/s, with consistent values obtained for H and He absorption lines. This low value strongly favors a neutron star primary: while a black hole cannot be excluded if the system is close to face on, such inclinations are disallowed by the observed rotation of the secondary. We also find the high-energy (X-ray and gamma-ray) flux maxima occur when the star is behind the compact object along our line of sight, inconsistent with a simple model of anisotropic inverse Compton scattering for the gamma-ray photons.

  6. Broadband spectroscopy of the eclipsing high mass X-ray binary 4U 1700-37 with Suzaku

    E-Print Network [OSTI]

    Jaisawal, Gaurava K

    2015-01-01

    We present the results obtained from broadband spectroscopy of the high mass X-ray binary 4U 1700-37 using data from a Suzaku observation in 2006 September 13-14 covering 0.29-0.72 orbital phase range. The light curves showed significant and rapid variation in source flux during entire observation. We did not find any signature of pulsations in the light curves. However, a quasi-periodic oscillation at ~20 mHz was detected in the power density spectrum of the source. The 1-70 keV spectrum was fitted with various continuum models. However, we found that the partially absorbed high energy cutoff power-law and Negative and Positive power-law with Exponential cutoff (NPEX) models described the source spectrum well. Iron emission lines at 6.4 keV and 7.1 keV were detected in the source spectrum. An absorption like feature at ~39 keV was detected in the residuals while fitting the data with NPEX model. Considering the feature as cyclotron absorption line, the surface magnetic field of the neutron star was estimated...

  7. The Magneto Hydro Dynamical Model of KHz Quasi Periodic Oscillations in Neutron Star Low Mass X-ray Binaries (II)

    E-Print Network [OSTI]

    Shi, Chang-Sheng; Li, Xiang-Dong

    2014-01-01

    We study the kilohertz quasi-periodic oscillations (kHz QPOs) in neutron star low mass X-ray binaries (LMXBs) with a new magnetohydrodynamics (MHD) model, in which the compressed magnetosphere is considered. The previous MHD model (Shi \\& Li 2009) is re-examined and the relation between the frequencies of the kHz QPOs and the accretion rate in LMXBs is obtained. Our result agrees with the observations of six sources (4U 0614+09, 4U 1636--53, 4U 1608--52, 4U 1915--15, 4U 1728--34, XTE 1807--294) with measured spins. In this model the kHz QPOs originate from the MHD waves in the compressed magnetosphere. The single kHz QPOs and twin kHz QPOs are produced in two different parts of the accretion disk and the boundary is close to the corotation radius. The lower QPO frequency in a frequency-accretion rate diagram is cut off at low accretion rate and the twin kHz QPOs encounter a top ceiling at high accretion rate due to the restriction of innermost stable circular orbit.

  8. Some Constraints On the Effects of Age and Metallicity on the Low Mass X-ray Binary Formation Rate

    E-Print Network [OSTI]

    Arunav Kundu; Thomas J. Maccarone; Stephen E. Zepf; Thomas H. Puzia

    2003-04-24

    We have studied the low mass X-ray binary (LMXB) populations within and outside globular clusters (GC) in NGC 4365 and NGC 3115. Using published age and metallicity constraints from optical and IR observations of their GCs, we do not find any evidence for an increase in the LMXB formation rate in the intermediate age cluster population of NGC 4365, as has been proposed in some scenarios of dynamical LMXB formation in GCs. The old, metal-rich, red population of GCs in NGC 3115 on the other hand is {\\it at least} three times as efficient at creating LMXBs as the old, metal-poor, blue clusters. These data suggest that the higher formation efficiency of LMXBs in the red GC subsystems of many galaxies is largely a consequence of their higher metallicity. A comparison of the densities of field LMXBs in different galaxies does not reveal an obvious correlation with the age of the field stars as predicted by models in which the LMXB formation rate in the field drops monotonically with time after an initial burst. This suggests that either a significant fraction of the field LMXBs are created in GCs and subsequently injected into the field, or the LMXB formation rate has a more complex time evolution pattern.

  9. High-resolution magnetohydrodynamics simulation of black hole-neutron star merger: Mass ejection and short gamma-ray burst

    E-Print Network [OSTI]

    Kenta Kiuchi; Yuichiro Sekiguchi; Koutarou Kyutoku; Masaru Shibata; Keisuke Taniguchi; Tomohide Wada

    2015-06-22

    We report results of a high-resolution numerical-relativity simulation for the merger of black hole-magnetized neutron star binaries on Japanese supercomputer "K". We focus on a binary that is subject to tidal disruption and subsequent formation of a massive accretion torus. We find the launch of thermally driven torus wind, subsequent formation of a funnel wall above the torus and a magnetosphere with collimated poloidal magnetic field, and high Blandford-Znajek luminosity. We show for the first time this picture in a self-consistent simulation. The turbulence-like motion induced by the non-axisymmetric magnetorotational instability as well as the Kelvin-Helmholtz instability inside the accretion torus works as an agent to drive the mass accretion and converts the accretion energy to thermal energy, which results in the generation of a strong wind. By an in-depth resolution study, we reveal that high resolution is essential to draw such a picture. We also discuss the implication for the r-process nucleosynthesis, the radioactively-powered transient emission, and short gamma-ray bursts.

  10. High-resolution magnetohydrodynamics simulation of black hole-neutron star merger: Mass ejection and short gamma-ray burst

    E-Print Network [OSTI]

    Kenta Kiuchi; Yuichiro Sekiguchi; Koutarou Kyutoku; Masaru Shibata; Keisuke Taniguchi; Tomohide Wada

    2015-09-03

    We report results of a high-resolution numerical-relativity simulation for the merger of black hole-magnetized neutron star binaries on Japanese supercomputer "K". We focus on a binary that is subject to tidal disruption and subsequent formation of a massive accretion torus. We find the launch of thermally driven torus wind, subsequent formation of a funnel wall above the torus and a magnetosphere with collimated poloidal magnetic field, and high Blandford-Znajek luminosity. We show for the first time this picture in a self-consistent simulation. The turbulence-like motion induced by the non-axisymmetric magnetorotational instability as well as the Kelvin-Helmholtz instability inside the accretion torus works as an agent to drive the mass accretion and converts the accretion energy to thermal energy, which results in the generation of a strong wind. By an in-depth resolution study, we reveal that high resolution is essential to draw such a picture. We also discuss the implication for the r-process nucleosynthesis, the radioactively-powered transient emission, and short gamma-ray bursts.

  11. IMPULSIVE ACCELERATION OF CORONAL MASS EJECTIONS. II. RELATION TO SOFT X-RAY FLARES AND FILAMENT ERUPTIONS

    SciTech Connect (OSTI)

    Bein, B. M.; Berkebile-Stoiser, S.; Veronig, A. M.; Temmer, M.; Vrsnak, B.

    2012-08-10

    Using high time cadence images from the STEREO EUVI, COR1, and COR2 instruments, we derived detailed kinematics of the main acceleration stage for a sample of 95 coronal mass ejections (CMEs) in comparison with associated flares and filament eruptions. We found that CMEs associated with flares reveal on average significantly higher peak accelerations and lower acceleration phase durations, initiation heights, and heights, at which they reach their peak velocities and peak accelerations. This means that CMEs that are associated with flares are characterized by higher and more impulsive accelerations and originate from lower in the corona where the magnetic field is stronger. For CMEs that are associated with filament eruptions we found only for the CME peak acceleration significantly lower values than for events that were not associated with filament eruptions. The flare rise time was found to be positively correlated with the CME acceleration duration and negatively correlated with the CME peak acceleration. For the majority of the events the CME acceleration starts before the flare onset (for 75% of the events) and the CME acceleration ends after the soft X-ray (SXR) peak time (for 77% of the events). In {approx}60% of the events, the time difference between the peak time of the flare SXR flux derivative and the peak time of the CME acceleration is smaller than {+-}5 minutes, which hints at a feedback relationship between the CME acceleration and the energy release in the associated flare due to magnetic reconnection.

  12. CONTINUED COOLING OF THE CRUST IN THE NEUTRON STAR LOW-MASS X-RAY BINARY KS 1731-260

    SciTech Connect (OSTI)

    Cackett, Edward M.; Miller, Jon M.; Brown, Edward F.; Cumming, Andrew; Degenaar, Nathalie; Wijnands, Rudy

    2010-10-20

    Some neutron star low-mass X-ray binaries have very long outbursts (lasting several years) which can generate a significant amount of heat in the neutron star crust. After the system has returned to quiescence, the crust then thermally relaxes. This provides a rare opportunity to study the thermal properties of neutron star crusts, putting constraints on the thermal conductivity and hence the structure and composition of the crust. KS 1731-260 is one of only four systems where this crustal cooling has been observed. Here, we present a new Chandra observation of this source approximately eight years after the end of the last outburst and four years since the last observation. We find that the source has continued to cool, with the cooling curve displaying a simple power-law decay. This suggests that the crust has not fully thermally relaxed yet and may continue to cool further. A simple power-law decay is in contrast to theoretical cooling models of the crust, which predict that the crust should now have cooled to the same temperature as the neutron star core.

  13. The galaxy cluster X-ray luminosity--gravitational mass relation in the light of the WMAP 3rd year data

    E-Print Network [OSTI]

    Reiprich, T H

    2006-01-01

    The 3rd year WMAP results mark a shift in best fit values of cosmological parameters compared to the 1st year data and the concordance cosmological model. We test the consistency of the new results with previous constraints on cosmological parameters from the HIFLUGCS galaxy cluster sample and the impact of this shift on the X-ray luminosity--gravitational mass relation. The measured X-ray luminosity function combined with the observed luminosity--mass relation are compared to mass functions predicted for given cosmological parameter values. The luminosity function and luminosity--mass relation derived previously from HIFLUGCS are in perfect agreement with mass functions predicted using the best fit parameter values from the 3rd year WMAP data (OmegaM=0.238, sigma8=0.74) and inconsistent with the concordance cosmological model (OmegaM=0.3, sigma8=0.9), assuming a flat Universe. Trying to force consistency with the concordance model requires artificially decreasing the normalization of the luminosity--mass rel...

  14. Attenuation compensation in TC-99M SPECT brain imaging: Use of attenuation maps derived from tranmission versus emission data

    SciTech Connect (OSTI)

    Pan, T.S.; Licho, R.; Penney, B.C. [Univ. of Massachusetts Mecical Center, Worcester, MA (United States)] [and others

    1994-05-01

    This study compares reconstructions of Tc-99m brain SPECT studies made using two methods of estimating the attenuation map: (1) transmission scanning, and (2) segmenting reconstructions of emission data and assigning attenuation coefficient values. A three-head SPECT system with fan beam collimators was used. Transmission scanning was performed using a line source at the focal line of a fan beam collimator right after the regular emission scan. The higher attenuation of the skull and the lower attenuation in the sinus cavities were identifiable despite the noise in the reconstructed transmission data due to: (1) the contamination of the transmission data by emission photons, (2) the maximum acquisition count rate imposed by the SPECT system, and (3) the clinical scanning time. Emission data were recorded using both photopeak and Compton scatter energy windows. Outlines of the head and the maxillary sinus could be obtained using only the Compton scatter reconstructions, whereas identifying the skull regions and the frontal sinus required the photopeak data as well. We placed appropriate linear attenuation coefficients in the soft tissue, bone, sinus and air regions (0.15,. 0.22, 0, and 0 cm{sup -1}) and blurred this attenuation map with a Gaussian kernel of about 0.2 cm standard deviation to obtain the attenuation map based on the emission data. Reconstructions were computed using the maximum likelihood expectation maximization algorithm with Siddon`s ray-tracing algorithm. Reconstructions based on the two attenuation maps were compared quantitatively on the patient data. The differences noted were quite small. These results imply that attenuation correction based on emission data alone may be adequate for Tc-99m SPECT brain imaging.

  15. Constraining the formation of black-holes in short-period Black-Hole Low-Mass X-ray Binaries

    E-Print Network [OSTI]

    Repetto, Serena

    2015-01-01

    The formation of stellar mass black holes is still very uncertain. Two main uncertainties are the amount of mass ejected in the supernova event (if any) and the magnitude of the natal kick the black hole receives at birth (if any). Repetto et al. (2012), studying the position of Galactic X-ray binaries containing black holes, found evidence for black holes receiving high natal kicks at birth. In this Paper we extend that study, taking into account the previous binary evolution of the sources as well. The seven short-period black-hole X-ray binaries that we use, are compact binaries consisting of a low-mass star orbiting a black hole in a period less than $1$ day. We trace their binary evolution backwards in time, from the current observed state of mass-transfer, to the moment the black hole was formed, and we add the extra information on the kinematics of the binaries. We find that several systems could be explained by no natal kick, just mass ejection, while for two systems (and possibly more) a high kick is...

  16. 55-Gallon Drum Attenuation Corrections for Waste Assay Measurements

    SciTech Connect (OSTI)

    Casella, V.R.

    2002-04-03

    The present study shows how the percent attenuation for low-level waste (LLW), carbon-steel 55-gallon drums (44 and 46 mil) and for transuranic (TRU) DOT Type 7A 55-gallon drums (approximately 61 mil) changes with gamma energy from 60 keV to 1400 keV. Attenuation for these drums is in the range of 5 to 15 percent at energies from 400 to 1400 keV and from 15 to 35 percent at energies from 120 to 400 keV. At 60 keV, these drums attenuate 70-80 percent of the gamma rays. Correction factors were determined in order to correct for gamma attenuation of a TRU drum if a calibration is performed with a LLW drum. These correction factors increase the activities of the TRU drum by from 10 percent to 2 percent in the energy range of 165 to 1400 keV, with an increase of about 50 percent at 60 keV. Correction factors for TRU drums and for analyses without a drum were used to adjust the percent yield for frequently measured gamma rays, so that the assay libraries could be modified to provide the drum attenuation corrections.

  17. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect (OSTI)

    Joel Walls; M.T. Taner; Gary Mavko; Jack Dvorkin

    2002-04-01

    Wave-induced variations of pore pressure in a partially-saturated reservoir result in oscillatory liquid flow. The viscous losses during this flow are responsible for wave attenuation. The same viscous effects determine the changes in the dynamic bulk modulus of the system versus frequency. These changes are necessarily linked to attenuation via the causality condition. We analytically quantify the frequency dependence of the bulk modulus of a partially saturated rock by assuming that saturation is patchy and then link these changes to the inverse quality factor. As a result, the P-wave attenuation is quantitatively linked to saturation and thus can serve as a saturation indicator.

  18. QUARK-NOVAE IN LOW-MASS X-RAY BINARIES. II. APPLICATION TO G87-7 AND TO GRB 110328A

    SciTech Connect (OSTI)

    Ouyed, Rachid; Staff, Jan; Jaikumar, Prashanth

    2011-12-20

    We propose a simple model explaining two outstanding astrophysical problems related to compact objects: (1) that of stars such as G87-7 (alias EG 50) that constitute a class of relatively low-mass white dwarfs (WDs) which nevertheless fall away from the C/O composition and (2) that of GRB 110328A/Swift J164449.3+57345 which showed spectacularly long-lived strong X-ray flaring, posing a challenge to standard gamma-ray burst models. We argue that both these observations may have an explanation within the unified framework of a quark-nova (QN) occurring in a low-mass X-ray binary (LMXB; neutron star (NS)-WD). For LMXBs, where the binary separation is sufficiently tight, ejecta from the exploding NS triggers nuclear burning in the WD on impact, possibly leading to Fe-rich composition compact WDs with mass 0.43 M{sub Sun} < M{sub WD} < 0.72 M{sub Sun }, reminiscent of G87-7. Our results rely on the assumption, which ultimately needs to be tested by hydrodynamic and nucleosynthesis simulations, that under certain circumstances the WD can avoid the thermonuclear runaway. For heavier WDs (i.e., M{sub WD} > 0.72 M{sub Sun }) experiencing the QN shock, degeneracy will not be lifted when carbon burning begins, and a sub-Chandrasekhar Type Ia supernova may result in our model. Under slightly different conditions and for pure He WDs (i.e., M{sub WD} < 0.43 M{sub Sun }), the WD is ablated and its ashes raining down on the quark star (QS) leads to accretion-driven X-ray luminosity with energetics and duration reminiscent of GRB 110328A. We predict additional flaring activity toward the end of the accretion phase if the QS turns into a black hole.

  19. Dipolar dark matter in light of 3.5 keV X-ray Line, Neutrino mass and LUX data

    E-Print Network [OSTI]

    Patra, Sudhanwa; Sahu, Narendra

    2014-01-01

    A simple extension of the standard model (SM) providing transient magnetic moments to right-handed neutrinos is presented. In this model, the decay of next-to-lightest right-handed heavy neutrino to the lightest one and a photon (N 2 -> N 1 + gamma) can explain the 3.5 keV X-ray line signal observed by XMM-Newton X-ray observatory. Beside the SM particles and heavy right-handed Majorana neutrinos, the model contains a singly charged scalar (H) and an extra Higgs doublet (Sigma). Within this minimal set of extra fields the sub-eV masses of left-handed neutrinos are also explained. Moreover, we show that the spin-independent DM-nucleon cross-section is compatible with latest LUX data.

  20. Electron attenuation in free, neutral ethane clusters

    SciTech Connect (OSTI)

    Winkler, M.; Harnes, J.; Børve, K. J.; Myrseth, V.

    2014-10-28

    The electron effective attenuation length (EAL) in free, neutral ethane clusters has been determined at 40 eV kinetic energy by combining carbon 1s x-ray photoelectron spectroscopy and theoretical lineshape modeling. More specifically, theory is employed to form model spectra on a grid in cluster size (N) and EAL (?), allowing N and ? to be determined by optimizing the goodness-of-fit ?{sup 2}(N, ?) between model and observed spectra. Experimentally, the clusters were produced in an adiabatic-expansion setup using helium as the driving gas, spanning a range of 100–600 molecules in mean cluster size. The effective attenuation length was determined to be 8.4?±?1.9 Å, in good agreement with an independent estimate of 10 Å formed on the basis of molecular electron-scattering data and Monte Carlo simulations. The aggregation state of the clusters as well as the cluster temperature and its importance to the derived EAL value are discussed in some depth.

  1. Mass composition of cosmic rays with energy above 10**17 eV according to surface detectors of the Yakutsk EAS array

    E-Print Network [OSTI]

    Glushkov, A V

    2014-01-01

    We discuss the lateral distribution of charged particles in extensive air showers with energy above $10^{17}$ eV measured by surface scintillation detectors of Yakutsk EAS array. The analysis covers the data obtained during the period from 1977 to 2013. Experimental values are compared to theoretical predictions obtained with the use of CORSIKA code within frameworks of different hadron interaction models. The best agreement between theory and experiment is observed for QGSJet01 and QGSJet-II-04 models. A change in the cosmic ray mass composition towards proton is observed in the energy range $(1-20) \\times 10^{17}$ eV.

  2. Galaxies in X-ray Selected Clusters and Groups in Dark Energy Survey Data: Stellar Mass Growth of Bright Central Galaxies Since z~1.2

    E-Print Network [OSTI]

    Zhang, Y; Mckay, T; Rooney, P; Evrard, A E; Romer, A K; Perfecto, R; Song, J; Desai, S; Mohr, J; Wilcox, H; Bermeo, A; Jeltema, T; Hollowood, D; Bacon, D; Capozzi, D; Collins, C; Das, R; Gerdes, D; Hennig, C; Hilton, M; Hoyle, B; Kay, S; Liddle, A; Mann, R G; Mehrtens, N; Nichol, R C; Papovich, C; Sahlén, M; Soares-Santos, M; Stott, J; Viana, P T; Abbott, T; Abdalla, F B; Banerji, M; Bauer, A H; Benoit-Lévy, A; Bertin, E; Brooks, D; Buckley-Geer, E; Burke, D L; Rosell, A Carnero; Castander, F J; Diehl, H T; Doel, P; Cunha, C E; Eifler, T F; Neto, A Fausti; Fernandez, E; Flaugher, B; Fosalba, P; Frieman, J; Gaztanaga, E; Gruen, D; Gruendl, R A; Honscheid, K; James, D; Kuehn, K; Kuropatkin, N; Lahav, O; Maia, M A G; Makler, M; Marshall, J L; Martini, Paul; Miquel, R; Ogando, R; Plazas, A A; Roodman, A; Rykoff, E S; Sako, M; Sanchez, E; Scarpine, V; Schubnell, M; Sevilla, I; Smith, R C; Sobreira, F; Suchyta, E; Swanson, M E C; Tarle, G; Thaler, J; Tucker, D; Vikram, V; Da Costa, L N

    2015-01-01

    Using the science verification data of the Dark Energy Survey (DES) for a new sample of 106 X-Ray selected clusters and groups, we study the stellar mass growth of Bright Central Galaxies (BCGs) since redshift 1.2. Compared with the expectation in a semi-analytical model applied to the Millennium Simulation, the observed BCGs become under-massive/under-luminous with decreasing redshift. We incorporate the uncertainties associated with cluster mass, redshift, and BCG stellar mass measurements into analysis of a redshift-dependent BCG-cluster mass relation, $m_{*}\\propto(\\frac{M_{200}}{1.5\\times 10^{14}M_{\\odot}})^{0.24\\pm 0.08}(1+z)^{-0.19\\pm0.34}$, and compare the observed relation to the simulation prediction. We estimate the average growth rate since z = 1.0 for BCGs hosted by clusters of $M_{200, z}=10^{13.8}M_{\\odot}$, at $z=1.0$: $m_{*, BCG}$ appears to have grown by $0.13\\pm0.11$ dex, in tension at $\\sim 2.5 \\sigma$ significance level with the 0.4 dex growth rate expected in the simulation. We show that...

  3. Long-lasting X-ray emission from type IIb supernova 2011dh and mass-loss history of the yellow supergiant progenitor

    SciTech Connect (OSTI)

    Maeda, Keiichi [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Katsuda, Satoru [RIKEN (The Institute of Physical and Chemical Research) Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198 (Japan); Bamba, Aya [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo-ku, Sagamihara, Kanagawa 252-5258 (Japan); Terada, Yukikatsu [Graduate School of Science and Engineering, Saitama University, Shimo-Okubo 255, Sakura, Saitama 338-8570 (Japan); Fukazawa, Yasushi, E-mail: keiichi.maeda@kusastro.kyoto-u.ac.jp [Department of Physical Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)

    2014-04-20

    Type IIb supernova (SN) 2011dh, with conclusive detection of an unprecedented yellow supergiant (YSG) progenitor, provides an excellent opportunity to deepen our understanding on the massive star evolution in the final centuries toward the SN explosion. In this paper, we report on detection and analyses of thermal X-ray emission from SN IIb 2011dh at ?500 days after the explosion on Chandra archival data, providing a solidly derived mass-loss rate of a YSG progenitor for the first time. We find that the circumstellar media should be dense, more than that expected from a Wolf-Rayet (W-R) star by one order of magnitude. The emission is powered by a reverse shock penetrating into an outer envelope, fully consistent with the YSG progenitor but not with a W-R progenitor. The density distribution at the outermost ejecta is much steeper than that expected from a compact W-R star, and this finding must be taken into account in modeling the early UV/optical emission from SNe IIb. The derived mass-loss rate is ?3 × 10{sup –6} M {sub ?} yr{sup –1} for the mass-loss velocity of ?20 km s{sup –1} in the final ?1300 yr before the explosion. The derived mass-loss properties are largely consistent with the standard wind mass-loss expected for a giant star. This is not sufficient to be a main driver to expel nearly all the hydrogen envelope. Therefore, the binary interaction, with a huge mass transfer having taken place at ? 1300 yr before the explosion, is a likely scenario to produce the YSG progenitor.

  4. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect (OSTI)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-04-01

    In this report we will show results of seismic and well log derived attenuation attributes from a deep water Gulf of Mexico data set. This data was contributed by Burlington Resources and Seitel Inc. The data consists of ten square kilometers of 3D seismic data and three well penetrations. We have computed anomalous seismic absorption attributes on the seismic data and have computed Q from the well log curves. The results show a good correlation between the anomalous absorption (attenuation) attributes and the presence of gas as indicated by well logs.

  5. Test of the Conserved Vector Current Hypothesis by beta-ray Angular Distribution Measurement in the Mass-8 System

    E-Print Network [OSTI]

    T. Sumikama; K. Matsuta; T. Nagatomo; M. Ogura; T. Iwakoshi; Y. Nakashima; H. Fujiwara; M. Fukuda; M. Mihara; K. Minamisono; T. Yamaguchi; T. Minamisono

    2011-05-09

    The beta-ray angular correlations for the spin alignments of 8Li and 8B have been observed in order to test the conserved vector current (CVC) hypothesis. The alignment correlation terms were combined with the known beta-alpha-angular correlation terms to determine all the matrix elements contributing to the correlation terms. The weak magnetism term, 7.5\\pm0.2, deduced from the beta-ray correlation terms was consistent with the CVC prediction 7.3\\pm0.2, deduced from the analog-gamma-decay measurement based on the CVC hypothesis. However, there was no consistent CVC prediction for the second-forbidden term associated with the weak vector current. The experimental value for the second-forbidden term was 1.0 \\pm 0.3, while the CVC prediction was 0.1 \\pm 0.4 or 2.1 \\pm 0.5.

  6. Spectral Softening Between Outburst and Quiescence In The Neutron Star Low-Mass X-Ray Binary SAX J1750.8-2900

    E-Print Network [OSTI]

    Allen, Jessamyn L; Homan, Jeroen; Chakrabarty, Deepto

    2015-01-01

    Tracking the spectral evolution of transiently accreting neutron stars between outburst and quiescence probes relatively poorly understood accretion regimes. Such studies are challenging because they require frequent monitoring of sources with luminosities below the thresholds of current all-sky X-ray monitors. We present the analysis of over 30 observations of the neutron star low-mass X-ray binary SAX J1750.8-2900 taken across four years with the X-ray telescope aboard Swift. We find spectral softening with decreasing luminosity both on long ($\\sim$1 year) and short ($\\sim$days to week) timescales. As the luminosity decreases from $4\\times10^{36}$ erg s$^{-1}$ to $ \\sim1\\times10^{35} $ erg s$^{-1}$ (0.5-10 keV), the power law photon index increases from from 1.4 to 2.9. Although not statistically required, our spectral fits allow an additional soft component that displays a decreasing temperature as the luminosity decreases from $4 \\times 10^{36} $ to $6 \\times 10^{34}$ erg s$^{-1}$. Spectral softening exhi...

  7. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect (OSTI)

    Joel Walls; M.T. Taner; Gary Mavko; Jack Dvorkin

    2002-07-01

    In fully-saturated rock and at ultrasonic frequencies, the microscopic squirt flow induced between the stiff and soft parts of the pore space by an elastic wave is responsible for velocity-frequency dispersion and attenuation. In the seismic frequency range, it is the macroscopic cross-flow between the stiffer and softer parts of the rock. We use the latter hypothesis to introduce simple approximate equations for velocity-frequency dispersion and attenuation in a fully water saturated reservoir. The equations are based on the assumption that in heterogeneous rock and at a very low frequency, the effective elastic modulus of the fully-saturated rock can be estimated by applying a fluid substitution procedure to the averaged (upscaled) dry frame whose effective porosity is the mean porosity and the effective elastic modulus is the Backus-average (geometric mean) of the individual dry-frame elastic moduli of parts of the rock. At a higher frequency, the effective elastic modulus of the saturated rock is the Backus-average of the individual fully-saturated-rock elastic moduli of parts of the rock. The difference between the effective elastic modulus calculated separately by these two methods determines the velocity-frequency dispersion. The corresponding attenuation is calculated from this dispersion by using (e.g.) the standard linear solid attenuation model.

  8. Seismic attenuation due to patchy saturation

    E-Print Network [OSTI]

    Masson, Y. J; Pride, S. R

    2011-01-01

    attenuation peak is observed at lower frequencies due to oilor when oil is invading water, a single attenuation peak isusing oil as fluid 1 and water as fluid 2. The two peaks in

  9. Inversion of the attenuated Radon transform

    E-Print Network [OSTI]

    Münster, Westfälische Wilhelms-Universität

    Inversion of the attenuated Radon transform F. Natterer Institut fur Numerische und instrumentelle@math.uni-muenster.de Abstract We derive an exact inversion formula for the attenuated Radon transform. The formula is closely for x 2 IR2, #12; 2 S1 Dax; #12; = 1Z 0 ax + t#12;dt : 1.1 The attenuated Radon transform Ra is de ned

  10. ENHANCEMENTS TO NATURAL ATTENUATION: SELECTED CASE STUDIES

    SciTech Connect (OSTI)

    Vangelas, K; W. H. Albright, W; E. S. Becvar, E; C. H. Benson, C; T. O. Early, T; E. Hood, E; P. M. Jardine, P; M. Lorah, M; E. Majche, E; D. Major, D; W. J. Waugh, W; G. Wein, G; O. R. West, O

    2007-05-15

    In 2003 the US Department of Energy (DOE) embarked on a project to explore an innovative approach to remediation of subsurface contaminant plumes that focused on introducing mechanisms for augmenting natural attenuation to achieve site closure. Termed enhanced attenuation (EA), this approach has drawn its inspiration from the concept of monitored natural attenuation (MNA).

  11. Subsurface Contaminant Focus Area: Monitored Natural Attenuation (MNA)--Programmatic, Technical, and Regulatory Issues

    SciTech Connect (OSTI)

    Krupka, Kenneth M.; Martin, Wayne J.

    2001-07-23

    Natural attenuation processes are commonly used for remediation of contaminated sites. A variety of natural processes occur without human intervention at all sites to varying rates and degrees of effectiveness to attenuate (decrease) the mass, toxicity, mobility, volume, or concentration of organic and inorganic contaminants in soil, groundwater, and surface water systems. The objective of this review is to identify potential technical investments to be incorporated in the Subsurface Contaminant Focus Area Strategic Plan for monitored natural attenuation. When implemented, the technical investments will help evaluate and implement monitored natural attenuation as a remediation option at DOE sites. The outcome of this review is a set of conclusions and general recommendations regarding research needs, programmatic guidance, and stakeholder issues pertaining to monitored natural attenuation for the DOE complex.

  12. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect (OSTI)

    Joel Walls; M.T. Taner; Gary Mavko; Jack Dvorkin

    2002-01-01

    In Section 1 of this first report we will describe the work we are doing to collect and analyze rock physics data for the purpose of modeling seismic attenuation from other measurable quantities such as porosity, water saturation, clay content and net stress. This work and other empirical methods to be presented later, will form the basis for ''Q pseudo-well modeling'' that is a key part of this project. In Section 2 of this report, we will show the fundamentals of a new method to extract Q, dispersion, and attenuation from field seismic data. The method is called Gabor-Morlet time-frequency decomposition. This technique has a number of advantages including greater stability and better time resolution than spectral ratio methods.

  13. A Systematic Study of X-Ray Flares from Low-Mass Young Stellar Objects in the Rho Ophiuchi Star-Forming Region with Chandra

    E-Print Network [OSTI]

    K. Imanishi; H. Nakajima; M. Tsujimoto; K. Koyama; Y. Tsuboi

    2003-05-10

    We report on the results of a systematic study of X-ray flares from low-mass young stellar objects, using Chandra observations of the main region of the Rho Oph. From 195 X-ray sources, including class I-III sources and some young brown dwarfs, we detected a total of 71 X-ray flares. Most of the flares have the typical profile of solar and stellar flares, fast rise and slow decay. We derived the time-averaged temperature (kT), luminosity (L_X), rise and decay timescales (tau_r and tau_d) of the flares, finding that (1) class I-II sources tend to have a high kT, (2) the distribution of L_X during flares is nearly the same for all classes, and (3) positive and negative log-linear correlations are found between tau_r and tau_d, and kT and tau_r. In order to explain these relations, we used the framework of magnetic reconnection model to formulate the observational parameters as a function of the half-length of the reconnected magnetic loop (L) and magnetic field strength (B). The estimated L is comparable to the typical stellar radius of these objects (10^{10-11} cm), which indicates that the observed flares are triggered by solar-type loops, rather than larger ones (10^{12} cm) connecting the star with its inner accretion disk. The higher kT observed for class I sources may be explained by a higher magnetic field strength (about 500 G) than for class II-III sources (200-300 G).

  14. Nuclear attenuation of three-hadron systems in neutrino-induced reactions

    E-Print Network [OSTI]

    N. M. Agababyan; L. Grigorian; N. Grigoryan; H. Gulkanyan; A. A. Ivanilov; Zh. Karamyan; V. A. Korotkov

    2011-08-08

    For the first time, the nuclear attenuation of three hadron systems is studied in neutrino-induced reactions using the data obtained with SKAT bubble chamber. The strongest attenuation (R_3 ~ 0.6) is observed for a system carrying an overwhelming fraction of the current quark energy, as well as for a system with the smallest effective mass. An indication is obtained that the correlation effects in the nuclear attenuation play only a minor role. The experimental data are compared with predictions of the quark string fragmentation model.

  15. Enhanced Attenuation Technologies: Passive Soil Vapor Extraction

    SciTech Connect (OSTI)

    Vangelas, K.; Looney, B.; Kamath, R.; Adamson, D.; Newell, C.

    2010-03-15

    Passive soil vapor extraction (PSVE) is an enhanced attenuation (EA) approach that removes volatile contaminants from soil. The extraction is driven by natural pressure gradients between the subsurface and atmosphere (Barometric Pumping), or by renewable sources of energy such as wind or solar power (Assisted PSVE). The technology is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction (ASVE) to natural attenuation. PSVE systems are simple to design and operate and are more cost effective than active systems in many scenarios. Thus, PSVE is often appropriate as an interim-remedial or polishing strategy. Over the past decade, PSVE has been demonstrated in the U.S. and in Europe. These demonstrations provide practical information to assist in selecting, designing and implementing the technology. These demonstrations indicate that the technology can be effective in achieving remedial objectives in a timely fashion. The keys to success include: (1) Application at sites where the residual source quantities, and associated fluxes to groundwater, are relatively low; (2) Selection of the appropriate passive energy source - barometric pumping in cases with a deep vadose zone and barrier (e.g., clay) layers that separate the subsurface from the atmosphere and renewable energy assisted PSVE in other settings and where higher flow rates are required. (3) Provision of sufficient access to the contaminated vadose zones through the spacing and number of extraction wells. This PSVE technology report provides a summary of the relevant technical background, real-world case study performance, key design and cost considerations, and a scenario-based cost evaluation. The key design and cost considerations are organized into a flowchart that dovetails with the Enhanced Attenuation: Chlorinated Organics Guidance of the Interstate Technology and Regulatory Council (ITRC). The PSVE flowchart provides a structured process to determine if the technology is, or is not, reasonable and defensible for a particular site. The central basis for that decision is the expected performance of PSVE under the site specific conditions. Will PSVE have sufficient mass removal rates to reduce the release, or flux, of contamination into the underlying groundwater so that the site can meet it overall remedial objectives? The summary technical information, case study experiences, and structured decision process provided in this 'user guide' should assist environmental decision-makers, regulators, and engineers in selecting and successfully implementing PSVE at appropriate sites.

  16. Low-mass right-handed sneutrino dark matter: SuperCDMS and LUX constraints and the Galactic Centre gamma-ray excess

    SciTech Connect (OSTI)

    Cerdeño, D.G.; Peiró, M.; Robles, S. E-mail: miguel.peiro@uam.es

    2014-08-01

    Recent results from direct and indirect searches for dark matter (DM) have motivated the study of particle physics models that can provide weakly interacting massive particles (WIMPs) in the mass range 1–50 GeV. Viable candidates for light WIMP DM must fulfil stringent constraints. On the one hand, the observation at the LHC of a Higgs boson with Standard Model properties set an upper bound on the coupling of light DM particles to the Higgs, thereby making it difficult to reproduce the correct relic abundance. On the other hand, the recent results from direct searches in the CDMSlite, SuperCDMS and LUX experiments have set upper constraints on the DM scattering cross section. In this paper, we investigate the viability of light right-handed sneutrino DM in the Next-to-Minimal Supersymmetric Model (NMSSM) in the light of these constraints. To this aim, we have carried out a scan in the NMSSM parameter space, imposing experimental bounds on the Higgs sector and low-energy observables, such as the muon anomalous magnetic moment and branching ratios of rare decays. We demonstrate that the enlarged Higgs sector of the NMSSM, together with the flexibility provided by the RH sneutrino parameters, make it possible to obtain viable RH sneutrino DM with a mass as light as 2 GeV. We have also considered the upper bounds on the annihilation cross section from Fermi LAT data on dwarf spheroidal galaxies, and extracted specific examples with mass in the range 8–50 GeV that could account for the apparent low-energy excess in the gamma-ray emission at the Galactic Centre. Then, we have computed the theoretical predictions for the elastic scattering cross-section of RH sneutrinos. Finally, after imposing the recent bounds from SuperCDMS and LUX, we have found a wide area of the parameter space that could be probed by future low-threshold direct detection experiments.

  17. Shock-Wave Attenuation and Energy-Dissipation Potential of Granular Materials

    E-Print Network [OSTI]

    Grujicic, Mica

    Shock-Wave Attenuation and Energy-Dissipation Potential of Granular Materials Mica Grujicic, B this approach, both compression shocks and decompression waves are treated as (stress, specific volume, particle velocity, mass-based internal energy density, temperature, and mass-based entropy density) propagating

  18. High-resolution magnetohydrodynamics simulation of black hole-neutron star merger: Mass ejection and short gamma-ray burst

    E-Print Network [OSTI]

    Kiuchi, Kenta; Kyutoku, Koutarou; Shibata, Masaru; Taniguchi, Keisuke; Wada, Tomohide

    2015-01-01

    We report results of a high-resolution numerical-relativity simulation for the merger of black hole-magnetized neutron star binaries on Japanese supercomputer "K". We focus on a binary that is subject to tidal disruption and subsequent formation of a massive accretion torus. We find the launch of thermally driven torus wind, subsequent formation of a funnel wall above the torus and a magnetosphere with collimated poloidal magnetic field, and high Blandford-Znajek luminosity. We show for the first time this picture in a self-consistent simulation. The turbulence-like motion induced by the non-axisymmetric magnetorotational instability as well as the Kelvin-Helmholtz instability inside the accretion torus works as an agent to drive the mass accretion and converts the accretion energy to thermal energy, which results in the generation of a strong wind. By an in-depth resolution study, we reveal that high resolution is essential to draw such a picture. We also discuss the implication for the r-process nucleosynth...

  19. Extensional wave attenuation and velocity in partially-saturated sand in the sonic frequency range

    SciTech Connect (OSTI)

    Liu, Z.; Rector, J.W.; Nihei, K.T.; Tomutsa, L.; Myer, L.R.; Nakagawa, S.

    2002-06-17

    Extensional wave attenuation and velocity measurements on a high permeability Monterey sand were performed over a range of gas saturations for imbibition and degassing conditions. These measurements were conducted using extensional wave pulse propagation and resonance over a 1 - 9 kHz frequency range for a hydrostatic confining pressure of 8.3 MPa. Analysis of the extensional wave data and the corresponding X-ray CT images of the gas saturation show strong attenuation resulting from the presence of the gas (QE dropped from 300 for the dry sand to 30 for the partially-saturated sand), with larger attenuation at a given saturation resulting from heterogeneous gas distributions. The extensional wave velocities are in agreement with Gassmann theory for the test with near-homogeneous gas saturation and with a patchy saturation model for the test with heterogeneous gas saturation. These results show that partially-saturated sands under moderate confining pressure can produce strong intrinsic attenuation for extensional waves.

  20. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect (OSTI)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-04-01

    In this report we will show some new Q related seismic attributes on the Burlington-Seitel data set. One example will be called Energy Absorption Attribute (EAA) and is based on a spectral analysis. The EAA algorithm is designed to detect a sudden increase in the rate of exponential decay in the relatively higher frequency portion of the spectrum. In addition we will show results from a hybrid attribute that combines attenuation with relative acoustic impedance to give a better indication of commercial gas saturation.

  1. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect (OSTI)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-12-01

    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  2. Analysis of passivated A-286 stainless steel surfaces for mass spectrometer inlet systems by Auger electron and X-ray photoelectron spectroscopy and scanning electron microscopy

    SciTech Connect (OSTI)

    Ajo, Henry; Blankenship, Donnie; Clark, Elliot

    2014-07-25

    In this study, various commercially available surface treatments are being explored for use on stainless steel components in mass spectrometer inlet systems. Type A-286 stainless steel coupons, approximately 12.5 mm in diameter and 3 mm thick, were passivated with one of five different surface treatments; an untreated coupon served as a control. The surface and near-surface microstructure and chemistry of the coupons were investigated using sputter depth profiling using Auger electron spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). All the surface treatments studied appeared to change the surface morphology dramatically, as evidenced by lack of tool marks on the treated samples in SEM images. In terms of the passivation treatment, Vendors A-D appeared to have oxide layers that were very similar in thickness to each other (0.7–0.9 nm thick), as well as to the untreated samples (the untreated sample oxide layers appeared to be somewhat larger). Vendor E’s silicon coating appears to be on the order of 200 nm thick.

  3. A 2.15 hr ORBITAL PERIOD FOR THE LOW-MASS X-RAY BINARY XB 1832-330 IN THE GLOBULAR CLUSTER NGC 6652

    SciTech Connect (OSTI)

    Engel, M. C.; Heinke, C. O.; Sivakoff, G. R.; Elshamouty, K. G.; Edmonds, P. D. E-mail: heinke@ualberta.ca

    2012-03-10

    We present a candidate orbital period for the low-mass X-ray binary (LMXB) XB 1832-330 in the globular cluster NGC 6652 using a 6.5 hr Gemini South observation of the optical counterpart of the system. Light curves in g' and r' for two LMXBs in the cluster, sources A and B in previous literature, were extracted and analyzed for periodicity using the ISIS image subtraction package. A clear sinusoidal modulation is evident in both of A's curves, of amplitude {approx}0.11 mag in g' and {approx}0.065 mag in r', while B's curves exhibit rapid flickering, of amplitude {approx}1 mag in g' and {approx}0.5 mag in r'. A Lomb-Scargle test revealed a 2.15 hr periodic variation in the magnitude of A with a false alarm probability less than 10{sup -11}, and no significant periodicity in the light curve for B. Though it is possible that saturated stars in the vicinity of our sources partially contaminated our signal, the identification of A's binary period is nonetheless robust.

  4. A Method for energy estimation and mass composition determination of primary cosmic rays at Chacaltaya observation level based on atmospheric Cerenkov light technique

    E-Print Network [OSTI]

    S. Mavrodiev; A. Mishev; J. Stamenov

    2003-10-23

    A new method for energy and mass composition estimation of primary cosmic ray radiation based on atmospheric Cerenkov light flux in extensive air showers (EAS) analysis is proposed. The Cerenkov light flux in EAS initiated by primary protons and iron nuclei is simulated with CORSIKA 5.62 code for Chacaltaya observation level (536 g/cm2) in the energy range 10 TeV - 10 PeV. An adequate model, approximation of lateral distribution of Cerenkov light in showers is obtained. Using the proposed model and solution of overdetermined system of nonlinear equations based on Gauss Newton method with autoregularization, two different array detector arrangements are compared. The detector response for the detector sets is simulated. The accuracies in energy and shower axis determination are studied and the corresponding selection criteria are proposed. An approximation with nonlinear fit is obtained and the energy dependence of the proposed model function parameters is studied. The approximation of model parameters as function of the primary energy is carried out. This permits, taking into account the properties of the proposed method and model, to distinguish proton primaries from iron primaries. The detector response for the detector sets is simulated and the accuracies in energy determination are calculated. Moreover the accuracies in shower axis determination are studied and criteria in shower axis position estimation are proposed.

  5. Analysis of passivated A-286 stainless steel surfaces for mass spectrometer inlet systems by Auger electron and X-ray photoelectron spectroscopy and scanning electron microscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Ajo, Henry; Blankenship, Donnie; Clark, Elliot

    2014-07-25

    In this study, various commercially available surface treatments are being explored for use on stainless steel components in mass spectrometer inlet systems. Type A-286 stainless steel coupons, approximately 12.5 mm in diameter and 3 mm thick, were passivated with one of five different surface treatments; an untreated coupon served as a control. The surface and near-surface microstructure and chemistry of the coupons were investigated using sputter depth profiling using Auger electron spectroscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy (SEM). All the surface treatments studied appeared to change the surface morphology dramatically, as evidenced by lack of tool marks onmore »the treated samples in SEM images. In terms of the passivation treatment, Vendors A-D appeared to have oxide layers that were very similar in thickness to each other (0.7–0.9 nm thick), as well as to the untreated samples (the untreated sample oxide layers appeared to be somewhat larger). Vendor E’s silicon coating appears to be on the order of 200 nm thick.« less

  6. ADVANCING THE SCIENCE OF NATURAL AND ENHANCED ATTENUATION FOR CHLORINATED SOLVENTS

    SciTech Connect (OSTI)

    Looney, B; TOM O. EARLY, T; TYLER GILMORE, T; FRANCIS H. CHAPELLE, F; NORMAN H. CUTSHALL, N; JEFF ROSS, J; MARK ANKENY, M; Michael Heitkamp, M; DAVID MAJOR, D; CHARLES J. NEWELL, C; W. JODY WAUGH, W; GARY WEIN, G; Karen Vangelas, K; Karen-M Adams, K; CLAIRE H. SINK, C

    2006-12-27

    This report summarizes the results of a three-year program that addressed key scientific and technical aspects related to natural and enhanced attenuation of chlorinated organics. The results from this coordinated three-year program support a variety of technical and regulatory advancements. Scientists, regulators, engineers, end-users and stakeholders participated in the program, which was supported by the U.S. Department of Energy (DOE) and the Interstate Technology and Regulatory Council (ITRC). The overarching objective of the effort was to examine environmental remedies that are based on natural processes--remedies such as Monitored Natural Attenuation (MNA) or Enhanced Attenuation (EA). A key result of the recent effort was the general affirmation of the approaches and guidance in the original U.S. Environmental Protection Agency (EPA) chlorinated solvent MNA protocols and directives from 1998 and 1999, respectively. The research program did identify several specific opportunities for advances based on: (1) mass balance as the central framework for attenuation based remedies, (2) scientific advancements and achievements during the past ten years, (3) regulatory and policy development and real-world experience using MNA, and (4) exploration of various ideas for integrating attenuation remedies into a systematic set of ''combined remedies'' for contaminated sites. These opportunities are summarized herein and are addressed in more detail in referenced project documents and journal articles, as well as in the technical and regulatory documents being developed within the ITRC. Natural attenuation processes occur in all soil and groundwater systems and act, to varying degrees, on all contaminants. Thus, a decision to rely on natural attenuation processes as part of a site-remediation strategy does not depend on the occurrence of natural attenuation, but on its effectiveness in meeting site-specific remediation goals. Meeting these goals typically requires low risk, plume stability, and documentation of accepted and sustainable attenuation processes. Plume stability and sustainability depend on the balance between contaminant loading into the plume and contaminant attenuation within the plume. This ''mass balance'' is a simple and powerful idea that developed into the central framework for all aspects of the DOE MNA/EA program. The centrality of mass balance has been advocated by Chapelle and others (e.g., 1995) for several years, and the concepts proved to be critical to conceptualizing natural attenuation remedies, designing enhancements, developing characterization and monitoring strategies, and developing regulatory decision frameworks that encourage broader use of MNA/EA with clarified technical responsibility.

  7. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    SciTech Connect (OSTI)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2002-10-01

    RSI has access to two synthetic seismic programs: Osiris seismic modeling system provided by Odegaard (Osiris) and synthetic seismic program, developed by SRB, implementing the Kennett method for normal incidence. Achieving virtually identical synthetic seismic traces from these different programs serves as cross-validation for both. The subsequent experiments have been performed with the Kennett normal incidence code because: We have access to the source code, which allowed us to easily control computational parameters and integrate the synthetics computations with our graphical and I/O systems. This code allows to perform computations and displays on a PC in MatLab or Octave environment, which is faster and more convenient. The normal incidence model allows us to exclude from the synthetic traces some of the physical effects that take place in 3-D models (like inhomogeneous waves) but have no relevance to the topic of our investigation, which is attenuation effects on seismic reflection and transmission.

  8. Attenuation structure of Coso geothermal area, California, from...

    Open Energy Info (EERE)

    Attenuation structure of Coso geothermal area, California, from wave pulse widths Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Attenuation...

  9. Cosmic-ray propagation at small scale: a support for protostellar disc formation

    E-Print Network [OSTI]

    Padovani, Marco; Hennebelle, Patrick; Commercon, Benoît; Joos, Marc

    2015-01-01

    As long as magnetic fields remain frozen into the gas, the magnetic braking prevents the formation of protostellar discs. This condition is subordinate to the ionisation fraction characterising the inmost parts of a collapsing cloud. The ionisation level is established by the number and the energy of the cosmic rays able to reach these regions. Adopting the method developed in our previous studies, we computed how cosmic rays are attenuated as a function of column density and magnetic field strength. We applied our formalism to low- and high-mass star formation models obtained by numerical simulations of gravitational collapse that include rotation and turbulence. In general, we found that the decoupling between gas and magnetic fields, condition allowing the collapse to go ahead, occurs only when the cosmic-ray attenuation is taken into account with respect to a calculation in which the cosmic-ray ionisation rate is kept constant. We also found that the extent of the decoupling zone also depends on the dust ...

  10. THE ATTENUATED RADON TRANSFORM: APPLICATION TO SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY IN THE PRESENCE OF A VARIABLE ATTENUATING MEDIUM

    E-Print Network [OSTI]

    Gullberg, Grant T.

    2013-01-01

    ·" 10276 vii THE ATTENUATED RADON TRANSFORM: APPLICATION TOOn the inversion of sampled Radon transforms, to appear as aMathematics THE ATTENUATED RADON TRANSFORM: APPLICATION TO

  11. Electrically tunable hot-silicon terahertz attenuator

    SciTech Connect (OSTI)

    Wang, Minjie; Vajtai, Robert; Ajayan, Pulickel M.; Kono, Junichiro

    2014-10-06

    We have developed a continuously tunable, broadband terahertz attenuator with a transmission tuning range greater than 10{sup 3}. Attenuation tuning is achieved electrically, by simply changing the DC voltage applied to a heating wire attached to a bulk silicon wafer, which controls its temperature between room temperature and ?550?K, with the corresponding free-carrier density adjusted between ?10{sup 11?}cm{sup ?3} and ?10{sup 17?}cm{sup ?3}. This “hot-silicon”-based terahertz attenuator works most effectively at 450–550?K (corresponding to a DC voltage variation of only ?7?V) and completely shields terahertz radiation above 550?K in a frequency range of 0.1–2.5 THz. Both intrinsic and doped silicon wafers were tested and demonstrated to work well as a continuously tunable attenuator. All behaviors can be understood quantitatively via the free-carrier Drude model taking into account thermally activated intrinsic carriers.

  12. 30TH INTERNATIONAL COSMIC RAY CONFERENCE Radio Detection of UltraHigh Energy Cosmic Rays

    E-Print Network [OSTI]

    Falcke, Heino

    offers a number of interesting advantages. Since radio waves suffer no attenuation, radio measurements30TH INTERNATIONAL COSMIC RAY CONFERENCE Radio Detection of Ultra­High Energy Cosmic Rays HEINO: The radio technique for the detection of cosmic particles has seen a major revival in recent years. New

  13. Split Hopkinson Resonant Bar Test for Sonic-Frequency Acoustic Velocity and Attenuation Measurements of Small, Isotropic Geologic Samples

    SciTech Connect (OSTI)

    Nakagawa, S.

    2011-04-01

    Mechanical properties (seismic velocities and attenuation) of geological materials are often frequency dependent, which necessitates measurements of the properties at frequencies relevant to a problem at hand. Conventional acoustic resonant bar tests allow measuring seismic properties of rocks and sediments at sonic frequencies (several kilohertz) that are close to the frequencies employed for geophysical exploration of oil and gas resources. However, the tests require a long, slender sample, which is often difficult to obtain from the deep subsurface or from weak and fractured geological formations. In this paper, an alternative measurement technique to conventional resonant bar tests is presented. This technique uses only a small, jacketed rock or sediment core sample mediating a pair of long, metal extension bars with attached seismic source and receiver - the same geometry as the split Hopkinson pressure bar test for large-strain, dynamic impact experiments. Because of the length and mass added to the sample, the resonance frequency of the entire system can be lowered significantly, compared to the sample alone. The experiment can be conducted under elevated confining pressures up to tens of MPa and temperatures above 100 C, and concurrently with x-ray CT imaging. The described Split Hopkinson Resonant Bar (SHRB) test is applied in two steps. First, extension and torsion-mode resonance frequencies and attenuation of the entire system are measured. Next, numerical inversions for the complex Young's and shear moduli of the sample are performed. One particularly important step is the correction of the inverted Young's moduli for the effect of sample-rod interfaces. Examples of the application are given for homogeneous, isotropic polymer samples and a natural rock sample.

  14. ESTIMATING INTRINSIC ATTENUATION FROM SEISMIC INTERFEROMETRY

    E-Print Network [OSTI]

    Snieder, Roel

    the subsurface are often assumed to be the response of elastic media that do not dissipate mechanical energy Institute of Technology. The attenuation of the motion of this building has been measured using seismic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii LIST OF FIGURES AND TABLES . . . . . . . . . . . . . . . . . . . . . . . . . vii LIST

  15. Velocity and attenuation in partially molten rocks

    SciTech Connect (OSTI)

    Mavko, G.M.

    1980-10-10

    Interpretation of seismic velocity and attenuation in partially molten rocks has been limited, with few exceptions, to models that assume the melt to be distributed either as spheres or as thin films. However, other melt phase geometries, such as interconnected tubes along grain edges, might equally well account for seismic observations if there is a much larger fraction of melt. Seismic velocity and attenuation are estimated in rocks in which the melt phase has the tube geometry, and the results are compared with results expected for the more familiar film model under similar conditions. For a given melt fraction, tubes are found to give moduli intermediate between moduli for rigid spherical inclusions and compliant films. For example, in polycrystalline olivine at 20 kbar the model predicts a decrease in V/sub s/ of 10% and a decrease in V/sub p/ of 5% at 0.05 melt fraction, without considering inelastic relaxation. Shear attenuation appears to be dominated by viscous flow of melt between the tubes and/or films. For olivine the tube model predicts the increment of relaxation due to melt, ..delta mu../..mu.., to be 0.01 at 0.05 melt fraction. Relaxation of the bulk modulus is dominated by flow between melt pockets of different shape, heat flow, and solid-melt phase change. If melt is present, considerable bulk attenuation is expected, although the relaxation may be observable only at long periods, outside the seismic body wave band.

  16. Scattering Versus Intrinsic Attenuation in the Near Surface: Measurements from Permanent Down-hole Geophones

    E-Print Network [OSTI]

    Mangriotis, Maria-Daphne

    2009-01-01

    DH. “Seismic Wave Attenuation,” Society of ExplorationDH. “Seismic Wave Attenuation,” Society of ExplorationDH. “Seismic Wave Attenuation,” Society of Exploration

  17. The measurement of attenuation from vertical seismic profiles 

    E-Print Network [OSTI]

    Davis, Francis Erwin

    1983-01-01

    and the calcareous content or the shales. Slightly to non-calcareous shales exhibrted the highest attenuation values. Calcareous to very calcareous shales; low porosity, cemented andstones; and limestones exhibited the lowest attenuatior values. No correlation... aligned on trough. VSP3 . . . 81 Figure 40. Cumulative attenuation and 90% confidence intervals. Downhole data. VSP3 83 Figure 41. Cumulative attenuation and 90% confidence intervals. Synthetic data. VSP3 85 Figure 42. Cumulative attenuation and 90...

  18. Extensional wave attenuation and velocity in partially saturated sand in the sonic frequency range

    SciTech Connect (OSTI)

    Liu, Z.; Rector, J.W.; Nihei, K.T.; Tomutsa, L.; Myer, L.R.; Nakagawa, S.

    2001-08-10

    Extensional wave attenuation and velocity measurements on a high permeability Monterey sand were performed over a range of gas saturations for imbibition and degassing conditions. These measurements were conducted using extensional wave pulse propagation and resonance over a 1-9 kHz frequency range for a hydrostatic confining pressure of 8.3 MPa. Analysis of the extensional wave data and the corresponding X-ray CT images of the gas saturation show strong attenuation resulting from the presence of the gas (Q{sub E} dropped from 300 for the dry sand to 30 for the partially-saturated sand), with larger attenuation at a given saturation resulting from heterogeneous gas distributions. The extensional wave velocities are in agreement with Gassmann theory for the test with near-homogeneous gas saturation and with a patchy saturation model for the test with heterogeneous gas saturation. These results show that partially-saturated sands under moderate confining pressure can produce strong intrinsic attenuation for extensional waves.

  19. Seismic Attenuation Inversion with t* Using tstarTomog.

    SciTech Connect (OSTI)

    Preston, Leiph

    2014-09-01

    Seismic attenuation is defined as the loss of the seismic wave amplitude as the wave propagates excluding losses strictly due to geometric spreading. Information gleaned from seismic waves can be utilized to solve for the attenuation properties of the earth. One method of solving for earth attenuation properties is called t*. This report will start by introducing the basic theory behind t* and delve into inverse theory as it pertains to how the algorithm called tstarTomog inverts for attenuation properties using t* observations. This report also describes how to use the tstarTomog package to go from observed data to a 3-D model of attenuation structure in the earth.

  20. THE ATTENUATED RADON TRANSFORM: THEORY AND APPLICATION IN MEDICINE AND BIOLOGY

    E-Print Network [OSTI]

    Gullberg, Grant Theodore

    2011-01-01

    The Attenuated Radon Transform . . . . . . . .The Modified Attenuated Radon Transform. . . . .ProjectionProjections Radon's Inversion Formula Back-Projection Back-

  1. Systematic Uncertainties in the Spectroscopic Measurements of Neutron-Star Masses and Radii from Thermonuclear X-ray Bursts. III. Absolute Flux Calibration

    E-Print Network [OSTI]

    Guver, Tolga; Marshall, Herman; Psaltis, Dimitrios; Guainazzi, Matteo; Diaz-Trigo, Maria

    2015-01-01

    Many techniques for measuring neutron star radii rely on absolute flux measurements in the X-rays. As a result, one of the fundamental uncertainties in these spectroscopic measurements arises from the absolute flux calibrations of the detectors being used. Using the stable X-ray burster, GS 1826-238, and its simultaneous observations by Chandra HETG/ACIS-S and RXTE/PCA as well as by XMM-Newton EPIC-pn and RXTE/PCA, we quantify the degree of uncertainty in the flux calibration by assessing the differences between the measured fluxes during bursts. We find that the RXTE/PCA and the Chandra gratings measurements agree with each other within their formal uncertainties, increasing our confidence in these flux measurements. In contrast, XMM-Newton EPIC-pn measures 14.0$\\pm$0.3% less flux than the RXTE/PCA. This is consistent with the previously reported discrepancy with the flux measurements of EPIC-pn, compared to EPIC-MOS1, MOS2 and ACIS-S detectors. We also address the calibration uncertainty in the RXTE/PCA int...

  2. High power radio frequency attenuation device

    DOE Patents [OSTI]

    Kerns, Quentin A. (Bloomingdale, IL); Miller, Harold W. (Winfield, IL)

    1984-01-01

    A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

  3. Gamma ray shielding and structural properties of Bi{sub 2}O{sub 3}?PbO?B{sub 2}O{sub 3}?V{sub 2}O{sub 5} glass system

    SciTech Connect (OSTI)

    Kaur, Kulwinder, E-mail: kanwarjitsingh@yahoo.com; Singh, K. J., E-mail: kanwarjitsingh@yahoo.com; Anand, Vikas, E-mail: kanwarjitsingh@yahoo.com [Department of Physics, Guru Nanak Dev University, Amritsar 143005 (India)

    2014-04-24

    The present work has been undertaken to evaluate the applicability of Bi{sub 2}O{sub 3}?PbO?B{sub 2}O{sub 3}?V{sub 2}O{sub 5} glass system as gamma ray shielding material. Gamma ray mass attenuation coefficient has been determined theoretically using WinXcom computer software developed by National Institute of Standards and Technology. A meaningful comparison of their radiation shielding properties has been made in terms of their half value layer parameter with standard radiation shielding concrete 'barite'. Structural properties of the prepared glass system have been investigated in terms of XRD and FTIR techniques in order to check the possibility of their commercial utility as alternate to conventional concrete for gamma ray shielding applications.

  4. Radar attenuation and temperature within the Greenland Ice Sheet

    E-Print Network [OSTI]

    2015-01-01

    on obliquely propagating radio waves, IEEE Trans. Geosci.dielectric attenuation of radio waves through ice is alsoattenuation of radio waves through ice is also temperature

  5. Attenuation-Based Remedies in the Subsurface Applied Field Research...

    Broader source: Energy.gov (indexed) [DOE]

    Field Research Initiative (ABRS AFRI) Located at the Savannah River Site in Aiken, South Carolina, the Attenuation-Based Remedies in the Subsurface Applied Field Research...

  6. Seismic attenuation due to wave-induced flow

    E-Print Network [OSTI]

    2004-01-03

    easily produces enough attenuation to explain the field data. INDEX TERMS: ...... magnitude appropriate for water/air and water/oil meniscii), one obtains that ...

  7. Seismic Velocity And Attenuation Structure Of The Geysers Geothermal...

    Open Energy Info (EERE)

    Seismic Velocity And Attenuation Structure Of The Geysers Geothermal Field, California Jump to: navigation, search OpenEI Reference LibraryAdd to library Journal Article: Seismic...

  8. Mode propagation and attenuation in lined ducts

    E-Print Network [OSTI]

    BI, Wenping

    2014-01-01

    Optimal impedance for each mode is an important concept in an infinitely long duct lined with uniform absorption material. However it is not valid for finite length linings. This is because that the modes in lined ducts are not power-orthogonal; the total sound power is not equal to the sum of the sound power of each mode; cross-power terms may play important roles. In this paper, we study sound propagation and attenuation in an infinite rigid duct lined with a finite length of lining impedance. The lining impedance may be axial segments and circumferentially non-uniform. We propose two new physical quantities Kp and S to describe the self-overlap of the left eigenfunction and right eigenfunction of one mode and the normalized overlap between modes, respectively. The two new physical quantities describe totally the mode behaviors in lined ducts.

  9. Gas sensor with attenuated drift characteristic

    DOE Patents [OSTI]

    Chen, Ing-Shin (Danbury, CT) [Danbury, CT; Chen, Philip S. H. (Bethel, CT) [Bethel, CT; Neuner, Jeffrey W. (Bethel, CT) [Bethel, CT; Welch, James (Fairfield, CT) [Fairfield, CT; Hendrix, Bryan (Danbury, CT) [Danbury, CT; Dimeo, Jr., Frank [Danbury, CT

    2008-05-13

    A sensor with an attenuated drift characteristic, including a layer structure in which a sensing layer has a layer of diffusional barrier material on at least one of its faces. The sensor may for example be constituted as a hydrogen gas sensor including a palladium/yttrium layer structure formed on a micro-hotplate base, with a chromium barrier layer between the yttrium layer and the micro-hotplate, and with a tantalum barrier layer between the yttrium layer and an overlying palladium protective layer. The gas sensor is useful for detection of a target gas in environments susceptible to generation or incursion of such gas, and achieves substantial (e.g., >90%) reduction of signal drift from the gas sensor in extended operation, relative to a corresponding gas sensor lacking the diffusional barrier structure of the invention

  10. Proton-air cross section measurement with the ARGO-YBJ cosmic ray experiment

    E-Print Network [OSTI]

    The ARGO-YBJ Collaboration

    2009-04-27

    The proton-air cross section in the energy range 1-100 TeV has been measured by the ARGO-YBJ cosmic ray experiment. The analysis is based on the flux attenuation for different atmospheric depths (i.e. zenith angles) and exploits the detector capabilities of selecting the shower development stage by means of hit multiplicity, density and lateral profile measurements at ground. The effects of shower fluctuations, the contribution of heavier primaries and the uncertainties of the hadronic interaction models, have been taken into account. The results have been used to estimate the total proton-proton cross section at center of mass energies between 70 and 500 GeV, where no accelerator data are currently available.

  11. hal-00154748,version1-14Jun2007 Attenuation Regulation

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    hal-00154748,version1-14Jun2007 Attenuation Regulation as a Term Rewriting System Eugene Asarin1,lyubetsk@iitp.ru Abstract The classical attenuation regulation of gene expression in bac- teria is considered. We propose a probabilistic term rewriting system modeling the whole process of such a regulation. 1 Introduction Modeling

  12. A model for the diffuse attenuation coefficient of downwelling irradiance

    E-Print Network [OSTI]

    Lee, Zhongping

    A model for the diffuse attenuation coefficient of downwelling irradiance Zhong-Ping Lee1 Naval] The diffuse attenuation coefficient for downwelling irradiance (Kd) is an important parameter for ocean of downwelling irradiance, J. Geophys. Res., 110, C02016, doi:10.1029/2004JC002275. 1. Introduction [2] Diffuse

  13. Thermal stability in the blended lithium manganese oxide – Lithium nickel cobalt manganese oxide cathode materials: An in situ time-resolved X-Ray diffraction and mass spectroscopy study

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hu, Enyuan; Bak, Seong Min; Senanayake, Sanjaya D.; Yang, Xiao-Qing; Nam, Kyung-Wan; Zhang, Lulu; Shao, Minhua

    2015-03-01

    Thermal stabilities of a series of blended LiMn2O4(LMO)-LiNi1/3Co1/3Mn1/3O2 (NCM) cathode materials with different weight ratios were studied by in situ time-resolved X-ray diffraction (XRD) combined with mass spectroscopy in the temperature range of 25°C-580°C under helium atmosphere. Upon heating, the electrochemically delithiated LMO changed into Mn3O4 phase at around 250°C. Formation of MnO with rocksalt structure started at 520°C. This observation is in contrast to the previous report for chemically delithiate LMO in air, in which a process of ?-MnO2 transforming to ?-MnO2 was observed. Oxygen peak was not observed in all cases, presumably as a result of either consumptionmore »by the carbon or detection limit. CO2 profile correlates well with the phase transition and indirectly suggests the oxygen release of the cathode. Introducing NCM into LMO has two effects: first, it makes the high temperature rock-salt phase formation more complicated with more peaks in CO2 profile due to different MO (M = Ni, Mn, Co) phases; secondly, the onset temperature of CO2 release is lowered, implying lowered oxygen release temperature. Upon heating, XRD patterns indicate the NCM part reacts first, followed by the LMO part. This confirms the better thermal stability of LMO over NCM.« less

  14. A clumpy stellar wind and luminosity-dependent cyclotron line revealed by the first Suzaku observation of the high-mass X-ray binary 4U 1538–522

    SciTech Connect (OSTI)

    Hemphill, Paul B.; Rothschild, Richard E.; Markowitz, Alex; Fürst, Felix; Pottschmidt, Katja; Wilms, Jörn

    2014-09-01

    We present results from the first Suzaku observation of the high-mass X-ray binary 4U 1538–522. The broadband spectral coverage of Suzaku allows for a detailed spectral analysis, characterizing the cyclotron resonance scattering feature at 23.0 ± 0.4 keV and the iron K? line at 6.426 ± 0.008 keV, as well as placing limits on the strengths of the iron K? line and the iron K edge. We track the evolution of the spectral parameters both in time and in luminosity, notably finding a significant positive correlation between cyclotron line energy and luminosity. A dip and spike in the light curve is shown to be associated with an order-of-magnitude increase in column density along the line of sight, as well as significant variation in the underlying continuum, implying the accretion of a overdense region of a clumpy stellar wind. We also present a phase-resolved analysis, with most spectral parameters of interest showing significant variation with phase. Notably, both the cyclotron line energy and the iron K? line intensity vary significantly with phase, with the iron line intensity significantly out of phase with the pulse profile. We discuss the implications of these findings in the context of recent work in the areas of accretion column physics and cyclotron resonance scattering feature formation.

  15. Thermal stability in the blended lithium manganese oxide – Lithium nickel cobalt manganese oxide cathode materials: An in situ time-resolved X-Ray diffraction and mass spectroscopy study

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Hu, Enyuan [Brookhaven National Lab. (BNL), Upton, NY (United States); Bak, Seong Min [Brookhaven National Lab. (BNL), Upton, NY (United States); Senanayake, Sanjaya D. [Brookhaven National Lab. (BNL), Upton, NY (United States); Yang, Xiao-Qing [Dongguk Univ., Seoul (Korea, Republic of). Dept. of Energy and Materials Engineering; Nam, Kyung-Wan [Dongguk Univ., Seoul (Korea, Republic of). Dept. of Energy and Materials Engineering] (ORCID:0000000162786369); Zhang, Lulu [Hong Kong Univ. of Science and Technology, Clear Water Bay (Hong Kong); Shao, Minhua

    2015-03-01

    Thermal stabilities of a series of blended LiMn2O4(LMO)-LiNi1/3Co1/3Mn1/3O2 (NCM) cathode materials with different weight ratios were studied by in situ time-resolved X-ray diffraction (XRD) combined with mass spectroscopy in the temperature range of 25°C-580°C under helium atmosphere. Upon heating, the electrochemically delithiated LMO changed into Mn3O4 phase at around 250°C. Formation of MnO with rocksalt structure started at 520°C. This observation is in contrast to the previous report for chemically delithiate LMO in air, in which a process of ?-MnO2 transforming to ?-MnO2 was observed. Oxygen peak was not observed in all cases, presumably as a result of either consumption by the carbon or detection limit. CO2 profile correlates well with the phase transition and indirectly suggests the oxygen release of the cathode. Introducing NCM into LMO has two effects: first, it makes the high temperature rock-salt phase formation more complicated with more peaks in CO2 profile due to different MO (M = Ni, Mn, Co) phases; secondly, the onset temperature of CO2 release is lowered, implying lowered oxygen release temperature. Upon heating, XRD patterns indicate the NCM part reacts first, followed by the LMO part. This confirms the better thermal stability of LMO over NCM.

  16. arXiv:0712.1036v1[astro-ph]6Dec2007 The lowest-mass stellar black holes: catastrophic death of neutron stars in gamma-ray

    E-Print Network [OSTI]

    Rasio, Frederic A.

    of neutron stars in gamma-ray bursts K. Belczynski1 , R. O'Shaughnessy2 , V. Kalogera3 , F. Rasio3 , R. Taam3 progenitors for short gamma-ray bursts. Indeed such a merger can produce a black hole with a transient a gamma-ray burst [3]. Using available binary pulsar observations supported by our extensive evolutionary

  17. Enhanced Attenuation: A Reference Guide On Approaches To Increase The Natural Treatment Capacity Of A System

    SciTech Connect (OSTI)

    Vangelas, K

    2006-01-30

    The objective of this document is to explore the realm of enhancements to natural attenuation processes for cVOCs and review examples that have been proposed, modeled, and implemented. We will identify lessons learned from these case studies to confirm that enhancements are technically feasible and have the potential to achieve a favorable, cost-effective contaminant mass balance. Furthermore, we hope to determine if opportunities for further improvement of the enhancements exist and suggest areas where new and innovative types of enhancements might be possible.

  18. ENHANCED ATTENUATION: A REFERENCE GUIDE ON APPROACHES TO INCREASE THE NATURAL TREATMENT CAPACITY OF A SYSTEM

    SciTech Connect (OSTI)

    Looney, B; Michael Heitkamp, M; Gary Wein , G; Karen Vangelas, K; Karen-M Adams, K; Tom Early; Bob Borden; David Major; W. Jody Waugh; Todd Wiedemeier; Claire H. Sink

    2006-08-10

    The objective of this document is to explore the realm of enhancements to natural attenuation processes for cVOCs and review examples that have been proposed, modeled, and implemented. We will identify lessons learned from these case studies to confirm that enhancements are technically feasible and have the potential to achieve a favorable, cost-effective contaminant mass balance. Furthermore, we hope to determine if opportunities for further improvement of the enhancements exist and suggest areas where new and innovative types of enhancements might be possible.

  19. Heat transfer in sound propagation and attenuation through gas-liquid polyhedral foams

    E-Print Network [OSTI]

    Yuri M. Shtemler; Isaac R. Shreiber

    2007-05-20

    A cell method is developed, which takes into account the bubble geometry of polyhedral foams, and provides for the generalized Rayleigh-Plesset equation that contains the non-local in time term corresponding to heat relaxation. The Rayleigh-Plesset equation together with the equations of mass and momentum balances for an effective single-phase inviscid fluid yield a model for foam acoustics. The present calculations reconcile observed sound velocity and attenuation with those predicted using the assumption that thermal dissipation is the dominant damping mechanism in a range of foam expansions and sound excitation frequencies.

  20. Broadband Lg Attenuation Modeling in the Middle East

    SciTech Connect (OSTI)

    Pasyanos, M E; Matzel, E M; Walter, W R; Rodgers, A J

    2008-08-21

    We present a broadband tomographic model of Lg attenuation in the Middle East derived from source- and site-corrected amplitudes. Absolute amplitude measurements are made on hand-selected and carefully windowed seismograms for tens of stations and thousands of crustal earthquakes resulting in excellent coverage of the region. A conjugate gradient method is used to tomographically invert the amplitude dataset of over 8000 paths over a 45{sup o} x 40{sup o} region of the Middle East. We solve for Q variation, as well as site and source terms, for a wide range of frequencies ranging from 0.5-10 Hz. We have modified the standard attenuation tomography technique to more explicitly define the earthquake source expression in terms of the seismic moment. This facilitates the use of the model to predict the expected amplitudes of new events, an important consideration for earthquake hazard or explosion monitoring applications. The attenuation results have a strong correlation to tectonics. Shields have low attenuation, while tectonic regions have high attenuation, with the highest attenuation at 1 Hz is found in eastern Turkey. The results also compare favorably to other studies in the region made using Lg propagation efficiency, Lg/Pg amplitude ratios and two-station methods. We tomographically invert the amplitude measurements for each frequency independently. In doing so, it appears the frequency-dependence of attenuation is not compatible with the power law representation of Q(f), an assumption that is often made.

  1. High energy cosmic rays, gamma rays and neutrinos from AGN

    E-Print Network [OSTI]

    Yukio Tomozawa

    2008-02-03

    The author reviews a model for the emission of high energy cosmic rays, gamma-rays and neutrinos from AGN (Active Galactic Nuclei) that he has proposed since 1985. Further discussion of the knee energy phenomenon of the cosmic ray energy spectrum requires the existence of a heavy particle with mass in the knee energy range. A possible method of detecting such a particle in the Pierre Auger Project is suggested. Also presented is a relation between the spectra of neutrinos and gamma-rays emitted from AGN. This relation can be tested by high energy neutrino detectors such as ICECUBE, the Mediterranean Sea Detector and possibly by the Pierre Auger Project.

  2. X-ray Observations of Mrk 231

    E-Print Network [OSTI]

    T. J. Turner

    1998-08-10

    This paper presents new X-ray observations of Mrk 231, an active galaxy of particular interest due to its large infrared luminosity and the presence of several blueshifted broad absorption line (BAL) systems, a phenomenon observed in a small fraction of QSOs. A ROSAT HRI image of Mrk 231 is presented, this shows an extended region of soft X-ray emission, covering several tens of kpc, consistent with the extent of the host galaxy. An ASCA observation of Mrk 231 is also presented. Hard X-rays are detected but the data show no significant variability in X-ray flux. The hard X-ray continuum is heavily attenuated and X-ray column estimates range from ~ 2 x 10^{22} - 10^{23} cm^{-2} depending on whether the material is assumed to be neutral or ionized, and on the model assumed for the extended X-ray component. These ASCA data provide only the second hard X-ray spectrum of a BAL AGN presented to date. The broad-band spectral-energy-distribution of the source is discussed. While Mrk 231 is X-ray weak compared to Seyfert 1 galaxies, it has an optical-to-X-ray spectrum typical of a QSO.

  3. Thermal stability in the blended lithium manganese oxide – Lithium nickel cobalt manganese oxide cathode materials: An in situ time-resolved X-Ray diffraction and mass spectroscopy study

    SciTech Connect (OSTI)

    Hu, Enyuan; Bak, Seong Min; Senanayake, Sanjaya D.; Yang, Xiao-Qing; Nam, Kyung-Wan; Zhang, Lulu; Shao, Minhua

    2015-03-01

    Thermal stabilities of a series of blended LiMn2O4(LMO)-LiNi1/3Co1/3Mn1/3O2 (NCM) cathode materials with different weight ratios were studied by in situ time-resolved X-ray diffraction (XRD) combined with mass spectroscopy in the temperature range of 25°C-580°C under helium atmosphere. Upon heating, the electrochemically delithiated LMO changed into Mn3O4 phase at around 250°C. Formation of MnO with rocksalt structure started at 520°C. This observation is in contrast to the previous report for chemically delithiate LMO in air, in which a process of ?-MnO2 transforming to ?-MnO2 was observed. Oxygen peak was not observed in all cases, presumably as a result of either consumption by the carbon or detection limit. CO2 profile correlates well with the phase transition and indirectly suggests the oxygen release of the cathode. Introducing NCM into LMO has two effects: first, it makes the high temperature rock-salt phase formation more complicated with more peaks in CO2 profile due to different MO (M = Ni, Mn, Co) phases; secondly, the onset temperature of CO2 release is lowered, implying lowered oxygen release temperature. Upon heating, XRD patterns indicate the NCM part reacts first, followed by the LMO part. This confirms the better thermal stability of LMO over NCM.

  4. New Constraint on Scalar Gauss-Bonnet Gravity and a Possible Explanation for the Excess of the Orbital Decay Rate in a Low-Mass X-ray Binary

    E-Print Network [OSTI]

    Kent Yagi

    2013-02-07

    It was recently shown that a black hole (BH) is the only compact object that can acquire a scalar charge in scalar Gauss-Bonnet (sGB) theory under the small coupling approximation. This leads to the fact that scalar radiation is emitted from a binary containing at least one BH. In this letter, we find the constraints on this theory from BH low-mass X-ray binaries (BH-LMXBs). The main result of this letter is that from the orbital decay rate of A0620-00, we obtained a conservative bound that is six orders of magnitude stronger than the solar system bound. In addition to this, we look at XTE J1118+480, whose orbital decay rate has been recently measured with an excess compared to the theoretical prediction in GR due to the radiation reaction. The cause of this excess is currently unknown. Although it is likely that the cause is of astrophysical origin, here we investigate the possibility of explaining this excess with the additional scalar radiation in sGB theory. We find that there still remains a parameter range where the excess can be explained while also satisfying the constraint obtained from A0620-00. The interesting point is that for most of other alternative theories of gravity, it seems difficult to explain this excess with the additional radiation. This is because it would be difficult to evade the constraints from binary pulsars or they have already been constrained rather strongly from other observations such as solar system experiments. We propose several ways to determine whether the excess is caused by the scalar radiation in sGB gravity including future gravitational wave observations with space-borne interferometers, which can give a constraint three orders of magnitude stronger than that from A0620-00.

  5. Modulus dispersion and attenuation in tuff and granite

    SciTech Connect (OSTI)

    Haupt, R.W.; Martin, R.J. III; Tang, X.; Dupree, W.J. [New England Research, Inc., White River Junction, VT (United States); Price, R.H. [Sandia National Labs., Albuquerque, NM (United States)

    1991-12-23

    The effects of loading frequency, strain amplitude, and saturation on elastic moduli and attenuation have been measured in samples of the Topopah Spring Member welded tuff. Four different laboratory techniques have been used to determine Young`s modulus and extensional wave attenuation at frequencies ranging from 10{sup {minus}2} to 10{sup 6} Hz. The results are compared with data acquired for Sierra White granite under the same conditions. The modulus and attenuation in room dry samples remain relatively constant over frequency. Frequency dependent attenuation and modulus dispersion are observed in the saturated samples and are attributed to fluid flow and sample size. The properties of tuff were independent of strain amplitude in room dry and saturated conditions.

  6. Simulation of E-Cloud Driven Instability And Its Attenuation...

    Office of Scientific and Technical Information (OSTI)

    Simulation of E-Cloud Driven Instability And Its Attenuation Using a Feedback System in the CERN SPS Citation Details In-Document Search Title: Simulation of E-Cloud Driven...

  7. CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION MODELING IN GROUNDWATER

    E-Print Network [OSTI]

    Boyer, Edmond

    CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION MODELING IN GROUNDWATER F. QUIOT1 , C.Goblet@ensmp.fr Keywords : numerical model, groundwater contamination, chlorinated solvents, natural atténuation atténuation models to predict transport and fate of chlorinated solvents in saturated groundwater Systems

  8. Wave energy attenuation and shoreline alteration characteristics of submerged breakwaters 

    E-Print Network [OSTI]

    Krafft, Katherine Margaret

    1993-01-01

    WAVE ENERGY ATTENUATION AND SHORELINE ALTERATION CHARACTERISTICS OF SUBMERGED BREAKWATERS A Thesis by KATHERINE MARGARET KRAFFT Submitted to the Office of Graduate Studies of Texas AIM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1993 Major Subject: Ocean Engineering WAVE ENERGY ATTENUATION AND SHORELINE ALTERATION CHARACTERISTICS OF SUBMERGED BREAKWATERS A Thesis by KATHERINE MARGARET KRAFFT Approved as to style and content by: John...

  9. THE ATTENUATED RADON TRANSFORM: APPLICATION TO SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY IN THE PRESENCE OF A VARIABLE ATTENUATING MEDIUM

    SciTech Connect (OSTI)

    Gullberg, Grant T.

    1980-03-01

    The properties of the attenuated Radon transform and its application to single-photon emission computed tomography (ECT) are analyzed in detail. In nuclear medicine and biological research, the objective of ECT is to describe quantitatively the position and strengths of internal sources of injected radiopharmaceuticals and radionuclides where the attenuation between the sources and detector is unknown. The problem is mathematically and practically quite different from well-known methods in transmission computed tomography (TCT) where only the attenuation is unknown. A mathematical structure using function theory and the theory of linear operators on Hilbert spaces is developed to better understand the spectral properties of the attenuated Radon transform. The continuous attenuated Radon transform is reduced to a matrix operator for discrete angular and lateral sampling, and the reconstruction problem reduces to a system of linear equations. For variable attenuation coefficients frequently found in imaging internal organs, the numerical methods developed in this paper involve iterative techniques of performing the generalized inverse. Its application to nuclear medicine is demonstrated by reconstructions of transverse sections of the brain, heart, and liver.

  10. Fluid distribution effect on sonic attenuation in partially saturated limestones

    SciTech Connect (OSTI)

    Cadoret, T. [Elf Exploration Production, Pau (France). Dept. Sismique] [Elf Exploration Production, Pau (France). Dept. Sismique; Mavko, G. [Stanford Univ., CA (United States)] [Stanford Univ., CA (United States); Zinszner, B. [Inst. Francais du Petrole, Rueil Malmaison (France). Lab. de Physique des Roches] [Inst. Francais du Petrole, Rueil Malmaison (France). Lab. de Physique des Roches

    1998-01-01

    Extensional and torsional wave-attenuation measurements are obtained at a sonic frequency around 1 kHz on partially saturated limestones using large resonant bars, 1 m long. To study the influence of the fluid distribution, the authors use two different saturation methods: drying and depressurization. When water saturation (S{sub w}) is higher than 70%, the extensional wave attenuation is found to depend on whether the resonant bar is jacketed. This can be interpreted as the Biot-Gardner-White effect. The experimental results obtained on jacketed samples show that, during a drying experiment, extensional wave attenuation is influenced strongly by the fluid content when S{sub w} is between approximately 70% and 100%. This sensitivity to fluid saturation vanishes when saturation is obtained through depressurization. Using a computer-assisted tomographic (CT) scan, the authors found that, during depressurization, the fluid distribution is homogeneous at the millimetric scale at all saturations. In contrast, during drying, heterogeneous saturation was observed at high water-saturation levels. Thus, the authors interpret the dependence of the extensional wave attenuation upon the saturation method as principally caused by a fluid distribution effect. Torsional attenuation shows no sensitivity to fluid saturation for S{sub w} between 5% and 100%.

  11. Automatic detection of bone fragments in poultry using multi-energy x-rays

    DOE Patents [OSTI]

    Gleason, Shaun S. (Knoxville, TN); Paulus, Michael J. (Knoxville, TN); Mullens, James A. (Knoxville, TN)

    2002-04-09

    At least two linear arrays of x-ray detectors are placed below a conveyor belt in a poultry processing plant. Multiple-energy x-ray sources illuminate the poultry and are detected by the detectors. Laser profilometry is used to measure the poultry thickness as the x-ray data is acquired. The detector readout is processed in real time to detect the presence of small highly attenuating fragments in the poultry, i.e., bone, metal, and cartilage.

  12. Solids mass flow indication with radiation

    DOE Patents [OSTI]

    Macko, Joseph E. (Irwin, PA); Estriplet, Isnard (Irwin, PA)

    1985-06-04

    Method and apparatus for indicating mass flow of a solid particulate material through a rotary feeder. A radiation source and detector are positioned in a manner whereby radiation flux is directed through, and attenuated by, particulate material contained in rotating pockets. A Cesium-137 gamma source can be mounted within the shaft of the feeder, and one or more detectors can be mounted outside of the feeder housing. The detected signal is indicative of the mass of particulate material contained within a given pocket rotating within the feeder.

  13. Modeling mesoscopic attenuation in a highly heterogeneous Biot's medium

    E-Print Network [OSTI]

    Santos, Juan

    and dispersion at seismic frequencies is known as mesoscopic loss, and is caused by the presence-wave diffusion process. It is also the case that the exact spatial distribution of these heterogeneities the effect of underground carbon dioxide (CO2) accumulations on the amplitude and attenuation of seismic

  14. ORIGINAL RESEARCH Attenuation of Lipopolysaccharide-Induced Lung Vascular

    E-Print Network [OSTI]

    Gardel, Margaret

    ORIGINAL RESEARCH Attenuation of Lipopolysaccharide-Induced Lung Vascular Stiffening by Lipoxin Reduces Lung Inflammation Fanyong Meng1 , Isa Mambetsariev1 , Yufeng Tian1 , Yvonne Beckham2 , Angelo. Birukova1 1 Lung Injury Center, Section of Pulmonary and Critical Care Medicine, Department of Medicine

  15. 5. SOUND ATTENUATION 5.1 NATURE OF SOUND WAVE

    E-Print Network [OSTI]

    Cambridge, University of

    5. SOUND ATTENUATION 5.1 NATURE OF SOUND WAVE Historically, acoustic is the scientific study of sound. Sound can be considered as a wave phenomenon. A sound wave is a longitudinal wave where particles the sound wave, the particles of the medium through which the sound moves is vibrating in a back and forth

  16. MODELING OF CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION IN GROUNDWATER

    E-Print Network [OSTI]

    Boyer, Edmond

    1 MODELING OF CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION IN GROUNDWATER QUIOT Fabrice1 performed by 4 teams (ANTEA, ENSMP, ENVIROS and INERIS) to simulate a contamination of groundwater is the evaluation of the fate of pollutants in groundwaters and soils. This knowledge is based on the result

  17. Dual energy CT for attenuation correction with PET/CT

    SciTech Connect (OSTI)

    Xia, Ting; Alessio, Adam M.; Kinahan, Paul E.

    2014-01-15

    Purpose: The authors evaluate the energy dependent noise and bias properties of monoenergetic images synthesized from dual-energy CT (DECT) acquisitions. These monoenergetic images can be used to estimate attenuation coefficients at energies suitable for positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging. This is becoming more relevant with the increased use of quantitative imaging by PET/CT and SPECT/CT scanners. There are, however, potential variations in the noise and bias of synthesized monoenergetic images as a function of energy. Methods: The authors used analytic approximations and simulations to estimate the noise and bias of synthesized monoenergetic images of water-filled cylinders with different shapes and the NURBS-based cardiac-torso (NCAT) phantom from 40 to 520 keV, the range of SPECT and PET energies. The dual-kVp spectra were based on the GE Lightspeed VCT scanner at 80 and 140 kVp with added filtration of 0.5 mm Cu. The authors evaluated strategies of noise suppression with sinogram smoothing and dose minimization with reduction of tube currents at the two kVp settings. The authors compared the impact of DECT-based attenuation correction with single-kVp CT-based attenuation correction on PET quantitation for the NCAT phantom for soft tissue and high-Z materials of bone and iodine contrast enhancement. Results: Both analytic calculations and simulations displayed the expected minimum noise value for a synthesized monoenergetic image at an energy between the mean energies of the two spectra. In addition the authors found that the normalized coefficient of variation in the synthesized attenuation map increased with energy but reached a plateau near 160 keV, and then remained constant with increasing energy up to 511 keV and beyond. The bias was minimal, as the linear attenuation coefficients of the synthesized monoenergetic images were within 2.4% of the known true values across the entire energy range. Compared with no sinogram smoothing, sinogram smoothing can dramatically reduce noise in the DECT-derived attenuation map. Through appropriate selection of tube currents for high and low kVp scans, DECT can deliver roughly the same amount of radiation dose as that of a single kVp CT scan, but could be used for PET attenuation correction with reduced bias in contrast agent regions by a factor of ?2.6 and slightly reduced RMSE for the total image. Conclusions: When DECT is used for attenuation correction at higher energies, there is a noise amplification that is dependent on the energy of the synthesized monoenergetic image of linear attenuation coefficients. Sinogram smoothing reduces the noise amplification in DECT-derived attenuation maps without increasing bias. With an appropriate selection of CT techniques, a DECT scan with the same radiation dose as a single CT scan can result in a PET image with improved quantitative accuracy.

  18. Diffusionally-accommodated Grain Boundary Sliding: Effects on Seismic Wave Attenuation

    E-Print Network [OSTI]

    Lee, Lik Chuan

    2010-01-01

    Wave Attenuation by Lik Chuan, Lee A dissertation submittedFall 2010 by Lik Chuan, Lee Abstract Diffusionally–Wave Attenuation by Lik Chuan, Lee Doctor of Philosophy in

  19. Reactive Transport Modeling of Natural Attenuation in Stormwater Bioretention Cells and Under Land Application of Wastewater 

    E-Print Network [OSTI]

    Zhang, Jingqiu

    2014-04-29

    Natural attenuation is a cost effective method to treat wastewater applied into soil. The natural attenuation process includes diffusion, dispersion, microbial activity, oxidation, mineral precipitation, sorption, and ion exchange to mitigate...

  20. Method for attenuating seismic shock from detonating explosive in an in situ oil shale retort

    DOE Patents [OSTI]

    Studebaker, Irving G. (Grand Junction, CO); Hefelfinger, Richard (Grand Junction, CO)

    1980-01-01

    In situ oil shale retorts are formed in formation containing oil shale by excavating at least one void in each retort site. Explosive is placed in a remaining portion of unfragmented formation within each retort site adjacent such a void, and such explosive is detonated in a single round for explosively expanding formation within the retort site toward such a void for forming a fragmented permeable mass of formation particles containing oil shale in each retort. This produces a large explosion which generates seismic shock waves traveling outwardly from the blast site through the underground formation. Sensitive equipment which could be damaged by seismic shock traveling to it straight through unfragmented formation is shielded from such an explosion by placing such equipment in the shadow of a fragmented mass in an in situ retort formed prior to the explosion. The fragmented mass attenuates the velocity and magnitude of seismic shock waves traveling toward such sensitive equipment prior to the shock wave reaching the vicinity of such equipment.

  1. Dispersion and attenuation for an acoustic wave equation consistent with viscoelasticity

    E-Print Network [OSTI]

    Andrzej Hanyga

    2014-01-30

    An acoustic wave equation for pressure accounting for viscoelastic attenuation is derived from viscoelastic equations of motion. It differs significantly from the equations proposed by Szabo. Dispersion and attenuation associated with the viscoelastic wave equation is examined. The theory is applied to three classes of viscoelastic models and to the linear attenuation model.

  2. Determination of power-law attenuation coefficient and dispersion spectra in multi-wall carbon nanotube

    E-Print Network [OSTI]

    Gladden, Josh

    Determination of power-law attenuation coefficient and dispersion spectra in multi-wall carbon for a set of multi-wall carbon nanotube MWCNT -nylon composites from pure nylon to 20% MWCNT by weight­Kronig relations, the attenuation and dispersion data were found to be consistent with a power-law attenuation

  3. Measurment and Interpretation of Seismic Attenuation for Hydrocarbon Exploration

    SciTech Connect (OSTI)

    Michael Batzle; Luca Duranti; James Rector; Steve Pride

    2007-12-31

    This research project is the combined effort of several leading research groups. Advanced theoretical work is being conducted at the Lawrence Berkeley National Laboratory. Here, the fundamental controls on loss mechanisms are being examined, primarily by use of numerical models of heterogeneous porous media. At the University of California, Berkeley, forward modeling is combined with direct measurement of attenuation. This forward modeling provides an estimate of the influence of 1/Q on the observed seismic signature. Direct measures of losses in Vertical Seismic Profiles (VSPs) indicate mechanisms to separate scattering versus intrinsic losses. At the Colorado School of Mines, low frequency attenuation measurements are combined with geologic models of deep water sands. ChevronTexaco is our corporate cosponsor and research partner. This corporation is providing field data over the Genesis Field, Gulf of Mexico. In addition, ChevronTexaco has rebuilt and improved their low frequency measurement system. Soft samples representative of the Genesis Field can now be measured for velocities and attenuations under reservoir conditions. Throughout this project we have: Assessed the contribution of mechanical compaction on time-lapse monitoring; Developed and tested finite difference code to model dispersion and attenuation; Heterogeneous porous materials were modeled and 1/Q calculated vs. frequency; 'Self-affine' heterogeneous materials with differing Hurst exponent modeled; Laboratory confirmation was made of meso-scale fluid motion influence on 1/Q; Confirmed theory and magnitude of layer-based scattering attenuation at Genesis and at a shallow site in California; Scattering Q's of between 40 and 80 were obtained; Measured very low intrinsic Q's (2-20) in a partially saturated vadose zone VSP; First field study to separate scattering and intrinsic attenuation in real data set; Revitalized low frequency device at ChevronTexaco's Richmond lab completed; First complete frequency dependent measurements on Berea sandstones from dry to various saturations (brine and decane); Frequency dependent forward modeling code is running, and tested on a couple of Cases--derives frequency dependent reflectivity from porosity based logs; Genesis seismic data obtained but is on hold until forward modeling is complete; Boundary and end effects modeled for soft material measurements at CSM; and Numerous papers published or submitted and presentations made.

  4. X-ray emission from O stars

    E-Print Network [OSTI]

    David H. Cohen

    2008-02-01

    Young O stars are strong, hard, and variable X-ray sources, properties which strongly affect their circumstellar and galactic environments. After ~1 Myr, these stars settle down to become steady sources of soft X-rays. I use high-resolution X-ray spectroscopy and MHD modeling to show that young O stars like theta-1 Ori C are well explained by the magnetically channeled wind shock scenario. After their magnetic fields dissipate, older O stars produce X-rays via shock heating in their unstable stellar winds. Here too I use X-ray spectroscopy and numerical modeling to confirm this scenario. In addition to elucidating the nature and cause of the O star X-ray emission, modeling of the high-resolution X-ray spectra of O supergiants provides strong evidence that mass-loss rates of these O stars have been overestimated.

  5. Quark Masses

    SciTech Connect (OSTI)

    Gasser, Juerg

    2005-10-26

    In my talk, I reviewed some basic aspects of quark masses: what do they mean, how can they be determined, what is our present knowledge on them. The talk was addressed to non specialists in the field, and so is this write up.

  6. Material identification based upon energy-dependent attenuation of neutrons

    DOE Patents [OSTI]

    Marleau, Peter

    2015-10-06

    Various technologies pertaining to identifying a material in a sample and imaging the sample are described herein. The material is identified by computing energy-dependent attenuation of neutrons that is caused by presence of the sample in travel paths of the neutrons. A mono-energetic neutron generator emits the neutron, which is downscattered in energy by a first detector unit. The neutron exits the first detector unit and is detected by a second detector unit subsequent to passing through the sample. Energy-dependent attenuation of neutrons passing through the sample is computed based upon a computed energy of the neutron, wherein such energy can be computed based upon 1) known positions of the neutron generator, the first detector unit, and the second detector unit; or 2) computed time of flight of neutrons between the first detector unit and the second detector unit.

  7. Bayesian Analysis of Peak Ground Acceleration Attenuation Relationship

    SciTech Connect (OSTI)

    Mu Heqing; Yuen Kaveng [Department of Civil and Environmental Engineering, University of Macau (China)

    2010-05-21

    Estimation of peak ground acceleration is one of the main issues in civil and earthquake engineering practice. The Boore-Joyner-Fumal empirical formula is well known for this purpose. In this paper we propose to use the Bayesian probabilistic model class selection approach to obtain the most suitable prediction model class for the seismic attenuation formula. The optimal model class is robust in the sense that it has balance between the data fitting capability and the sensitivity to noise. A database of strong-motion records is utilized for the analysis. It turns out that the optimal model class is simpler than the full order attenuation model suggested by Boore, Joyner and Fumal (1993).

  8. Galactic center gamma ray excess: features and possible origins

    E-Print Network [OSTI]

    ?umer, Slobodan

    Members, NASA / DOE & International Contributions (Sweden, France, Italy, Japan ...). Data made public! ! !"#$%&'()#*%+(',"-"."-* Space-based instruments only UV | X-ray | -ray | VHE -ray optical 10-11 10-12 10-13 10-14 10-15 10-16 Moresensitive Fergcm-2s-1) !"#$ !"%#$!"&#$!"'#$!"(#$!")#$ Energy !"#$% !"#$%&'() *+,"-#./ 0() 122 WIMP Mass

  9. Wideband measurements of ice sheet attenuation and basal scattering

    E-Print Network [OSTI]

    Allen, Christopher Thomas; Gogineni, Sivaprasad; Paden, J. D.; Jezek, K. C.; Dahl-Jensen, D.; Larsen, L. B.

    2005-04-01

    SENSING LETTERS, VOL. 2, NO. 2, APRIL 2005 Wideband Measurements of Ice Sheet Attenuation and Basal Scattering John D. Paden, Student Member, IEEE, Christopher T. Allen, Senior Member, IEEE, Sivaprasad Gogineni, Fellow, IEEE, Kenneth C. Jezek, Dorthe Dahl... the real part of the permittivity by [11] (4) and the imaginary part of the permittivity by [11] (5) To determine the total loss as the radio wave propagates to and from the bedrock, we discretize the temperature, density, and conductivity profiles shown...

  10. Expectations for the hard x-ray continuum and gamma-ray line...

    Office of Scientific and Technical Information (OSTI)

    continuum and gamma-ray lines from a Type Ia supernova dominate its integrated photon emissions and can provide unique diagnostics of the mass of the ejecta, the sup 56Ni yield...

  11. Gamma-ray shielding properties of some travertines in Turkey

    SciTech Connect (OSTI)

    Akkurt, Iskender; Guenoglu, Kadir

    2012-09-06

    The radiation is an essential phenomenon in daily life. There are various amounts of radioactivite substances in the underground and the earth was irradiated by this substances. Humans are exposed to various kind of radiation from these sources. The travertines are usually used as a coating material in buildings. In this study, the photon attenuation coefficients of some travertines have been measured using a gamma spectroscopy with NaI(Tl) detector. The measurements have been performed using {sup 60}Co source which gives 1173 and 1332 keV energies gamma rays and {sup 137}Cs source which gives 662 keV energy gamma rays and the results will be discussed.

  12. Cooled window for X-rays or charged particles

    DOE Patents [OSTI]

    Logan, C.M.

    1996-04-16

    A window is disclosed that provides good structural integrity and a very high capacity for removal of the heat deposited by x-rays, electrons, or ions, with minimum attenuation of the desired beam. The window is cooled by providing microchannels therein through which a coolant is pumped. For example, the window may be made of silicon with etched microchannels therein and covered by a silicon member. A window made of silicon with a total thickness of 520 {micro}m transmits 96% of the x-rays at an energy of 60 keV, and the transmission is higher than 90% for higher energy photons. 1 fig.

  13. Cooled window for X-rays or charged particles

    DOE Patents [OSTI]

    Logan, Clinton M. (Pleasanton, CA)

    1996-01-01

    A window that provides good structural integrity and a very high capacity for removal of the heat deposited by x-rays, electrons, or ions, with minimum attenuation of the desired beam. The window is cooled by providing microchannels therein through which a coolant is pumped. For example, the window may be made of silicon with etched microchannels therein and covered by a silicon member. A window made of silicon with a total thickness of 520 .mu.m transmits 96% of the x-rays at an energy of 60 keV, and the transmission is higher than 90% for higher energy photons.

  14. SU-E-T-411: Characterization of Novel Water-Equivalent PRESAGE for Megavoltage and Kilovoltage X-Ray Beam Dosimetry

    SciTech Connect (OSTI)

    Alqathami, M; Ibbott, G; Blencowe, A

    2014-06-01

    Purpose: To introduce and characterize novel water-equivalent PRESAGE dosimeters for megavoltage and kilovoltage X-ray beam dosimetry. Methods: Three novel metal-optimized PRESAGE dosimeters referred to as MO-PRESAGE 1, 2 and 3 were formulated. The radiological properties were key factors that were considered when formulating the new dosimeters. All formulations were prepared in spectrophotometric cuvettes, irradiated with a 6 MV X-ray beam, and the change in optical density was measured using a spectrophotometer. Their sensitivity, post-response stability, and water equivalency were investigated. Results: The results showed that all three formulations exhibited radiological properties closer to water than any of the commercially available PRESAGE formulations. For example, the novel MO-PRESAGE 1, 2 and 3 have mass densities only 3.9-4.4% higher than that of water, whereas the mass density for the commercial formulation is 5.3% higher. The novel formulations have almost identical Zeff values to that of water (7.42), while the Zeff for the commercial formulation was 3.7% higher than that of water. In addition, the MO-PRESAGE 3 formulation showed mass and energy attenuation coefficients that deviated from those of water by less than 50% relative to the commercial formulation. Furthermore, the reduced Zeff of the three different MOPRESAGE formulations resulted in a maximum variation in the probability of photoelectric absorption of 1.3 times than of water, compared to 1.8 times that of water for the commercial formulation. MO-PRESAGE 3 was also more sensitive to radiation than the other two new formulations introduced in this work due to the presence of alkylbromide radical initiators in the MO-PRESAGE 3 formulation. Conclusion: All three novel MOPRESAGE dosimeter formulations displayed excellent radiological properties, superior to any of the commercially available PRESAGE formulations and thus can be used for the dosimetry of clinical megavoltage and kilovoltage X-ray beams.

  15. X-ray lithography using holographic images

    DOE Patents [OSTI]

    Howells, M.S.; Jacobsen, C.

    1997-03-18

    Methods for forming X-ray images having 0.25 {micro}m minimum line widths on X-ray sensitive material are presented. A holographic image of a desired circuit pattern is projected onto a wafer or other image-receiving substrate to allow recording of the desired image in photoresist material. In one embodiment, the method uses on-axis transmission and provides a high flux X-ray source having modest monochromaticity and coherence requirements. A layer of light-sensitive photoresist material on a wafer with a selected surface is provided to receive the image(s). The hologram has variable optical thickness and variable associated optical phase angle and amplitude attenuation for transmission of the X-rays. A second embodiment uses off-axis holography. The wafer receives the holographic image by grazing incidence reflection from a hologram printed on a flat metal or other highly reflecting surface or substrate. In this second embodiment, an X-ray beam with a high degree of monochromaticity and spatial coherence is required. 15 figs.

  16. New Homogeneous Standards by Atomic Layer Deposition for Synchrotron X-ray Fluorescence and Absorption Spectroscopies.

    SciTech Connect (OSTI)

    Butterworth, A.L.; Becker, N.; Gainsforth, Z.; Lanzirotti, A.; Newville, M.; Proslier, T.; Stodolna, J.; Sutton, S.; Tyliszczak, T.; Westphal, A.J.; Zasadzinski, J. (UCB)

    2012-03-13

    Quantification of synchrotron XRF analyses is typically done through comparisons with measurements on the NIST SRM 1832/1833 thin film standards. Unfortunately, these standards are inhomogeneous on small scales at the tens of percent level. We are synthesizing new homogeneous multilayer standards using the Atomic Layer Deposition technique and characterizing them using multiple analytical methods, including ellipsometry, Rutherford Back Scattering at Evans Analytical, Synchrotron X-ray Fluorescence (SXRF) at Advanced Photon Source (APS) Beamline 13-ID, Synchrotron X-ray Absorption Spectroscopy (XAS) at Advanced Light Source (ALS) Beamlines 11.0.2 and 5.3.2.1 and by electron microscopy techniques. Our motivation for developing much-needed cross-calibration of synchrotron techniques is borne from coordinated analyses of particles captured in the aerogel of the NASA Stardust Interstellar Dust Collector (SIDC). The Stardust Interstellar Dust Preliminary Examination (ISPE) team have characterized three sub-nanogram, {approx}1{micro}m-sized fragments considered as candidates to be the first contemporary interstellar dust ever collected, based on their chemistries and trajectories. The candidates were analyzed in small wedges of aerogel in which they were extracted from the larger collector, using high sensitivity, high spatial resolution >3 keV synchrotron x-ray fluorescence spectroscopy (SXRF) and <2 keV synchrotron x-ray transmission microscopy (STXM) during Stardust ISPE. The ISPE synchrotron techniques have complementary capabilities. Hard X-ray SXRF is sensitive to sub-fg mass of elements Z {ge} 20 (calcium) and has a spatial resolution as low as 90nm. X-ray Diffraction data were collected simultaneously with SXRF data. Soft X-ray STXM at ALS beamline 11.0.2 can detect fg-mass of most elements, including cosmochemically important oxygen, magnesium, aluminum and silicon, which are invisible to SXRF in this application. ALS beamline 11.0.2 has spatial resolution better than 25 nm. Limiting factors for Stardust STXM analyses were self-imposed limits of photon dose due to radiation damage concerns, and significant attenuation of <1500 eV X-rays by {approx}80{micro}m thick, {approx}25 mg/cm{sup 3} density silica aerogel capture medium. In practice, the ISPE team characterized the major, light elements using STXM (O, Mg, Al, Si) and the heavier minor and trace elements using SXRF. The two data sets overlapped only with minor Fe and Ni ({approx}1% mass abundance), providing few quantitative cross-checks. New improved standards for cross calibration are essential for consortium-based analyses of Stardust interstellar and cometary particles, IDPs. Indeed, they have far reaching application across the whole synchrotron-based analytical community. We have synthesized three ALD multilayers simultaneously on silicon nitride membranes and silicon and characterized them using RBS (on Si), XRF (on Si{sub 3}N{sub 4}) and STXM/XAS (holey Si{sub 3}N{sub 4}). The systems we have started to work with are Al-Zn-Fe and Y-Mg-Er. We have found these ALD multi-layers to be uniform at {micro}m- to nm scales, and have found excellent consistency between four analytical techniques so far. The ALD films can also be used as a standard for e-beam instruments, eg., TEM EELS or EDX. After some early issues with the consistency of coatings to the back-side of the membrane windows, we are confident to be able to show multi-analytical agreement to within 10%. As the precision improves, we can use the new standards to verify or improve the tabulated cross-sections.

  17. Self-detection of x-ray Fresnel transmittivity using photoelectron-induced gas ionization

    E-Print Network [OSTI]

    Stoupin, Stanislav

    2015-01-01

    Electric response of an x-ray mirror enclosed in a gas flow ionization chamber was studied under the conditions of total external reflection for hard x-rays. It is shown that the electric response of the system as a function of the incidence angle is defined by x-ray Fresnel transmittivity and photon-electron attenuation properties of the mirror material. A simple interpretation of quantum yield of the system is presented. The approach provides non-invasive in-situ diagnostics of hard x-ray optics, easy access to complementary x-ray transmittivity data in x-ray reflectivity experiments and can also pave the way to novel schemes for angle and energy resolving x-ray detectors.

  18. Modeling Background Attenuation by Sample Matrix in Gamma Spectrometric Analyses

    SciTech Connect (OSTI)

    Bastos, Rodrigo O.; Appoloni, Carlos R. [Applied Nuclear Physics Laboratory-Department of Physics-CCE-State University of Londrina Campus Universitario-Rodovia Celso Garcia Cid s/n, Cx. Postal 6001, CEP 86051-990, Londrina, PR (Brazil)

    2008-08-07

    In laboratory gamma spectrometric analyses, the procedures for estimating background usually overestimate it. If an empty container similar to that used to hold samples is measured, it does not consider the background attenuation by sample matrix. If a 'blank' sample is measured, the hypothesis that this sample will be free of radionuclides is generally not true. The activity of this 'blank' sample is frequently sufficient to mask or to overwhelm the effect of attenuation so that the background remains overestimated. In order to overcome this problem, a model was developed to obtain the attenuated background from the spectrum acquired with the empty container. Beyond reasonable hypotheses, the model presumes the knowledge of the linear attenuation coefficient of the samples and its dependence on photon energy and samples densities. An evaluation of the effects of this model on the Lowest Limit of Detection (LLD) is presented for geological samples placed in cylindrical containers that completely cover the top of an HPGe detector that has a 66% relative efficiency. The results are presented for energies in the range of 63 to 2614keV, for sample densities varying from 1.5 to 2.5 g{center_dot}cm{sup -3}, and for the height of the material on the detector of 2 cm and 5 cm. For a sample density of 2.0 g{center_dot}cm{sup -3} and with a 2cm height, the method allowed for a lowering of 3.4% of the LLD for the energy of 1460keV, from {sup 40}K, 3.9% for the energy of 911keV from {sup 228}Ac, 4.5% for the energy of 609keV from {sup 214}Bi, and8.3% for the energy of 92keV from {sup 234}Th. For a sample density of 1.75 g{center_dot}cm{sup -3} and a 5cm height, the method indicates a lowering of 6.5%, 7.4%, 8.3% and 12.9% of the LLD for the same respective energies.

  19. High-power radio-frequency attenuation device

    DOE Patents [OSTI]

    Kerns, Q.A.; Miller, H.W.

    1981-12-30

    A resistor device for attenuating radio frequency power includes a radio frequency conductor connected to a series of fins formed of high relative magnetic permeability material. The fins are dimensional to accommodate the skin depth of the current conduction therethrough, as well as an inner heat conducting portion where current does not travel. Thermal connections for air or water cooling are provided for the inner heat conducting portions of each fin. Also disclosed is a resistor device to selectively alternate unwanted radio frequency energy in a resonant cavity.

  20. The Gas Flow from the Gas Attenuator to the Beam Line

    SciTech Connect (OSTI)

    Ryutov, D.D.

    2010-12-03

    The gas leak from the gas attenuator to the main beam line of the Linac Coherent Light Source has been evaluated, with the effect of the Knudsen molecular beam included. It has been found that the gas leak from the gas attenuator of the present design, with nitrogen as a working gas, does not exceed 10{sup -5} torr x l/s even at the highest pressure in the main attenuation cell (20 torr).

  1. Cosmic rays through the Higgs portal

    E-Print Network [OSTI]

    Rainer Dick; Robert B. Mann; Kai E. Wunderle

    2008-07-16

    We consider electroweak singlet dark matter with a mass comparable to the Higgs mass. The singlet is assumed to couple to standard matter through a perturbative coupling to the Higgs particle. The annihilation of a singlet with a mass comparable to the Higgs mass is dominated by proximity to the W, Z and Higgs peaks in the annihilation cross section. We find that the continuous photon spectrum from annihilation of a perturbatively coupled singlet in the galactic halo can reach a level of several per mil of the EGRET diffuse gamma ray flux.

  2. Gamma-Ray Pulsars: Models and Predictions

    E-Print Network [OSTI]

    Alice K. Harding

    2000-12-12

    Pulsed emission from gamma-ray pulsars originates inside the magnetosphere, from radiation by charged particles accelerated near the magnetic poles or in the outer gaps. In polar cap models, the high energy spectrum is cut off by magnetic pair production above an energy that is dependent on the local magnetic field strength. While most young pulsars with surface fields in the range B = 10^{12} - 10^{13} G are expected to have high energy cutoffs around several GeV, the gamma-ray spectra of old pulsars having lower surface fields may extend to 50 GeV. Although the gamma-ray emission of older pulsars is weaker, detecting pulsed emission at high energies from nearby sources would be an important confirmation of polar cap models. Outer gap models predict more gradual high-energy turnovers at around 10 GeV, but also predict an inverse Compton component extending to TeV energies. Detection of pulsed TeV emission, which would not survive attenuation at the polar caps, is thus an important test of outer gap models. Next-generation gamma-ray telescopes sensitive to GeV-TeV emission will provide critical tests of pulsar acceleration and emission mechanisms.

  3. Quantitative measurement of binary liquid distributions using multiple-tracer x-ray fluorescence and radiography

    SciTech Connect (OSTI)

    Halls, Benjamin R.; Meyer, Terrence R.; Kastengren, Alan L.

    2015-01-01

    The complex geometry and large index-of-refraction gradients that occur near the point of impingement of binary liquid jets present a challenging environment for optical interrogation. A simultaneous quadruple-tracer x-ray fluorescence and line-of-sight radiography technique is proposed as a means of distinguishing and quantifying individual liquid component distributions prior to, during, and after jet impact. Two different pairs of fluorescence tracers are seeded into each liquid stream to maximize their attenuation ratio for reabsorption correction and differentiation of the two fluids during mixing. This approach for instantaneous correction of x-ray fluorescence reabsorption is compared with a more time-intensive approach of using stereographic reconstruction of x-ray attenuation along multiple lines of sight. The proposed methodology addresses the need for a quantitative measurement technique capable of interrogating optically complex, near-field liquid distributions in many mixing systems of practical interest involving two or more liquid streams.

  4. Quantitative measurement of binary liquid distributions using multiple-tracer x-ray fluorescence and radiography

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Halls, Benjamin R.; Meyer, Terrence R.; Kastengren, Alan L.

    2015-01-23

    The complex geometry and large index-of-refraction gradients that occur near the point of impingement of binary liquid jets present a challenging environment for optical interrogation. A simultaneous quadruple-tracer x-ray fluorescence and line-of-sight radiography technique is proposed as a means of distinguishing and quantifying individual liquid component distributions prior to, during, and after jet impact. Two different pairs of fluorescence tracers are seeded into each liquid stream to maximize their attenuation ratio for reabsorption correction and differentiation of the two fluids during mixing. This approach for instantaneous correction of x-ray fluorescence reabsorption is compared with a more time-intensive approach of usingmore »stereographic reconstruction of x-ray attenuation along multiple lines of sight. The proposed methodology addresses the need for a quantitative measurement technique capable of interrogating optically complex, near-field liquid distributions in many mixing systems of practical interest involving two or more liquid streams.« less

  5. Cosmic Ray Radiography of the Damaged Cores of the Fukushima Reactors

    E-Print Network [OSTI]

    Borozdin, Konstantin; Luki?, Zarija; Milner, Edward Cas; Miyadera, Haruo; Morris, Christopher; Perry, John

    2012-01-01

    The passage of muons through matter is dominated by the Coulomb interaction with electrons and nuclei. The interaction with the electrons leads to continuous energy loss and stopping of the muons. The interaction with nuclei leads to angle diffusion. Two muon imaging methods that use flux attenuation and multiple Coulomb scattering of cosmic-ray muons are being studied as tools for diagnosing the damaged cores of the Fukushima reactors. Here we compare these two methods. We conclude that the scattering method can provide detailed information about the core. Attenuation has low contrast and little sensitivity to the core.

  6. Cosmic Ray Radiography of the Damaged Cores of the Fukushima Reactors

    E-Print Network [OSTI]

    Konstantin Borozdin; Steven Greene; Zarija Luki?; Edward Cas Milner; Haruo Miyadera; Christopher Morris; John Perry

    2012-09-13

    The passage of muons through matter is dominated by the Coulomb interaction with electrons and nuclei. The interaction with the electrons leads to continuous energy loss and stopping of the muons. The interaction with nuclei leads to angle diffusion. Two muon imaging methods that use flux attenuation and multiple Coulomb scattering of cosmic-ray muons are being studied as tools for diagnosing the damaged cores of the Fukushima reactors. Here we compare these two methods. We conclude that the scattering method can provide detailed information about the core. Attenuation has low contrast and little sensitivity to the core.

  7. A Plasma Instability Theory of Gamma-Ray Burst Emission

    E-Print Network [OSTI]

    J. J. Brainerd

    1999-04-02

    A plasma instability theory is presented for the prompt radiation from gamma-ray bursts. In the theory, a highly relativistic shell interacts with the interstellar medium through the filamentation and the two-stream instabilities to convert bulk kinetic energy into electron thermal energy and magnetic field energy. The processes are not efficient enough to satisfy the Rankine-Hugoniot conditions, so a shock cannot form through this mechanism. Instead, the interstellar medium passes through the shell, with the electrons radiating during this passage. Gamma-rays are produced by synchrotron self-Compton emission. Prompt optical emission is also produced through this mechanism, while prompt radio emission is produced through synchrotron emission. The model timescales are consistent with the shortest burst timescales. To emit gamma-rays, the shell's bulk Lorentz factor must be greater than approximately 1000. For the radiative processes to be efficient, the interstellar medium density must satisfy a lower limit that is a function of the bulk Lorentz factor. Because the limits operate as selection effects, bursts that violate them constitute new classes. In particular, a class of optical and ultraviolet bursts with no gamma-ray emission should exist. The lower limit on the density of the interstellar medium is consistent with the requirements of the Compton attenuation theory, providing an explanation for why all burst spectra appear to be attenuated. Several tests of the theory are discussed, as are the next theoretical investigations that should be conducted.

  8. H Loop shaping control for PLL-based mechanical resonance tracking in NEMS resonant mass sensors

    E-Print Network [OSTI]

    Boyer, Edmond

    problem that rejects the disturbance described by the resonance frequency shift, attenuates the phase the measurement scheme to a disturbance rejection control issue which considers the resonance frequency variation--A simple dynamic detection of the resonance frequency shift in NEMS resonant mass sensors is described

  9. X-rays from Hot Subdwarfs

    E-Print Network [OSTI]

    Mereghetti, Sandro

    2015-01-01

    Thanks to the high sensitivity of the instruments on board the XMM-Newton and Chandra satellites, it has become possible to explore the properties of the X-ray emission from hot subdwarfs. The small but growing sample of hot subdwarfs detected in X-rays includes binary systems, in which the X-rays result from wind accretion onto a compact companion (white dwarf or neutron star), as well as isolated sdO stars in which X-rays are probably due to shock instabilities in the wind. X-ray observations of these low mass stars provide information which can be useful also for our understanding of the winds of more luminous and massive early-type stars and can lead to the discovery of particularly interesting binary systems.

  10. Gamma Ray Bursts

    E-Print Network [OSTI]

    Stahl, Bennett

    2014-01-01

    Olson. “Observations of gamma-ray bursts of cosmic origin. ”E. Lingenfelter. “Gamma-ray bursts. ” Annual Review of652-654. Waxman, Eli. “Gamma-ray-burst afterglow: supporting

  11. Estimation of shear-wave interval attenuation from mode-converted data Bharath Shekar1

    E-Print Network [OSTI]

    Tsvankin, Ilya

    Tsvankin1 ABSTRACT Interval attenuation measurements provide valuable infor- mation for reservoir characterization and lithology discrimi- nation. We extend the attenuation layer-stripping method of Behura of the material (Prasad and Nur, 2003), the pre- sence of aligned fluid-filled fractures (Chapman, 2003; Batzle et

  12. Seismic-frequency attenuation and moduli estimates using a fiber-optic strainmeter Ludmila Adam 1

    E-Print Network [OSTI]

    Seismic-frequency attenuation and moduli estimates using a fiber-optic strainmeter Ludmila Adam 1 Summary We have developed a fiber-optic strainmeter to estimate velocities and attenuation at seismic properties such as broadband compressional and shear wave velocities, elastic moduli and seismic anisotropy

  13. Seismic attenuation due to wave-induced flow S. R. Pride

    E-Print Network [OSTI]

    Santos, Juan

    Seismic attenuation due to wave-induced flow S. R. Pride Earth Sciences Division, Lawrence Berkeley that squirt flow is incapable of explaining the measured level of loss (10À2 seismic enough attenuation to explain the field data. INDEX TERMS: 0935 Exploration Geophysics: Seismic methods

  14. Mon. Not. R. Astron. Soc. 396, 18251832 (2009) doi:10.1111/j.1365-2966.2009.14704.x Possible effects of pair echoes on gamma-ray burst afterglow emission

    E-Print Network [OSTI]

    Zhang, Bing

    2009-01-01

    effects of pair echoes on gamma-ray burst afterglow emission Kohta Murase,1 Bing Zhang,2 Keitaro Takahashi ABSTRACT High-energy emission from gamma-ray bursts (GRBs) is widely expected but had been sparsely and can escape from the emission region, they are attenuated by the cosmic infrared background photons

  15. X-ray Emission from Massive StarsX-ray Emission from Massive Stars David CohenDavid Cohen

    E-Print Network [OSTI]

    Cohen, David

    -rays Radiation-driven stellar windsRadiation-driven stellar winds The wind-shock paradigmThe wind-shock paradigm of the shock-heated windKinematics of the shock-heated wind Are mass-loss rates lower than we thought?Are mass Crescent Nebula - Tony HallasHallas wind-blown bubble: steady mass-losswind-blown bubble: steady mass

  16. Abstract--In this work, we first introduced a reorganized form of the Novikov's inversion formula for the attenuated Radon

    E-Print Network [OSTI]

    for the attenuated Radon transform with parallel-beam geometry which utilizes the conventional filters (such the attenuated Radon transform (AtRT). A closed- form inversion formula for parallel-beam (PB) geometry

  17. Layered 3D: tomographic image synthesis for attenuation-based light field and high dynamic range displays

    E-Print Network [OSTI]

    Wetzstein, Gordon

    We develop tomographic techniques for image synthesis on displays composed of compact volumes of light-attenuating material. Such volumetric attenuators recreate a 4D light field or high-contrast 2D image when illuminated ...

  18. Manufacturing techniques studies of ceramics by neutron and ?-ray radiography

    SciTech Connect (OSTI)

    Latini, R. M.; Bellido, A. V. B.; Souza, M. I. S.; Almeida, G. L.

    2014-11-11

    In this study, the aim was to evaluate capabilities and constraints of radiographic imagery using thermal neutrons and gamma-rays as tools to identify the type of technique employed in ceramics manufacturing especially that used in prehistoric Brazilian pottery from Acre state. For this purpose, radiographic images of test objects made with clay of this region using both techniques - palette and rollers - have been acquired with a system comprised of a source of gamma-rays or thermal neutrons and a corresponding X-ray or neutron-sensitive Imaging Plate as detector. For the neutrongraphy samples were exposed to a thermal neutron flux of order of 10{sup 5}n.cm{sup ?2}.s{sup ?1} for 3 minutes at main port of Argonauta research reactor of the Instituto de Engenharia Nuclear - IEN/CNEN. The radiographic images using ?-rays from {sup 165}Dy (95 keV) and {sup 198}Au (412 keV) both produced at this reactor, have been acquired under an exposure time of a couple of hours. After acquisition, images have undergone a treatment to improve their quality through enhancement of their contrast, a procedure involving corrections of the beam divergence, sample shape and averaging of the attenuation map profile. Preliminary results show that difference between manufacturing techniques is better identified by radiography using low energy ?-rays from {sup 165}Dy rather than neutrongraphy or ?-rays from {sup 198}Au. Nevertheless, disregarding the kind of employed radiation, it should be stressed that feasibility to apply the technique is tightly tied to homogeneity of the clay itself and tempers due to their different attenuation.

  19. Coated x-ray filters

    DOE Patents [OSTI]

    Steinmeyer, P.A.

    1992-11-24

    A radiation filter for filtering radiation beams of wavelengths within a preselected range of wavelengths comprises a radiation transmissive substrate and an attenuating layer deposited on the substrate. The attenuating layer may be deposited by a sputtering process or a vacuum process. Beryllium may be used as the radiation transmissive substrate. In addition, a second radiation filter comprises an attenuating layer interposed between a pair of radiation transmissive layers. 4 figs.

  20. Coated x-ray filters

    DOE Patents [OSTI]

    Steinmeyer, Peter A. (Farmington, NM)

    1992-11-24

    A radiation filter for filtering radiation beams of wavelengths within a preselected range of wavelengths comprises a radiation transmissive substrate and an attenuating layer deposited on the substrate. The attenuating layer may be deposited by a sputtering process or a vacuum process. Beryllium may be used as the radiation transmissive substrate. In addition, a second radiation filter comprises an attenuating layer interposed between a pair of radiation transmissive layers.

  1. Ultra High Energy Cosmic Rays: present status and future prospects

    E-Print Network [OSTI]

    A. A. Watson

    2001-12-20

    Reasons for the current interest in cosmic rays above 10^19 eV are described. The latest results on the energy spectrum, arrival direction distribution and mass composition of cosmic rays are reviewed, including data that were reported after the meeting in Blois in June 2001. The enigma set by the existence of ultra high-energy cosmic rays remains. Ideas proposed to explain it are discussed and progress with the construction of the Pierre Auger Observatory is outlined.

  2. Seismic Attenuation: Observations and Mechanisms M. Batzle, Ronny Hofmann, Manika Prasad, Colorado School of Mines; Gautam Kumar, BG Group;

    E-Print Network [OSTI]

    Seismic Attenuation: Observations and Mechanisms M. Batzle, Ronny Hofmann, Manika Prasad, Colorado, Summary Seismic attenuation and dispersion can be caused by numerous distinct mechanisms. Observed at best. Direct measurement of seismic attenuation (1/Q) and velocity dispersion in the laboratory help

  3. The effect of frequency on Young`s modulus and seismic wave attenuation

    SciTech Connect (OSTI)

    Price, R.H. [Sandia National Labs., Albuquerque, NM (United States). YMP Performance Assessment Applications Dept.; Martin, R.J. III; Haupt, R.W. [New England Research, Inc., White River Junction, VT (United States)

    1994-07-01

    Laboratory experiments were performed to measure the effect of frequency, water-saturation, and strain amplitude on Young`s modulus and seismic wave attenuation on rock cores recovered on or near the site of a potential nuclear waste repository at Yucca Mountain, Nevada. The purpose of this investigation is to perform the measurements using four techniques: cyclic loading, waveform inversion, resonant bar, and ultrasonic velocity. The measurements ranged in frequency between 10{sup {minus}2} and 10{sup 6} Hz. For the dry specimens Young`s modulus and attenuation were independent of frequency; that is, all four techniques yielded nearly the same values for modulus and attenuation. For saturated specimens, a frequency dependence for both Young`s modulus and attenuation was observed. In general, saturation reduced Young`s modulus and increased seismic wave attenuation. The effect of strain amplitude on Young`s modulus and attenuation was measured using the cyclic loading technique at a frequency of 10{sup {minus}1} Hz. The effect of strain amplitude in all cases was small. For some rocks, such as the potential repository horizon of the Topopah Spring Member tuff (TSw2), the effect of strain amplitude on both attenuation and modulus was minimal.

  4. Gamma ray generator

    DOE Patents [OSTI]

    Firestone, Richard B; Reijonen, Jani

    2014-05-27

    An embodiment of a gamma ray generator includes a neutron generator and a moderator. The moderator is coupled to the neutron generator. The moderator includes a neutron capture material. In operation, the neutron generator produces neutrons and the neutron capture material captures at least some of the neutrons to produces gamma rays. An application of the gamma ray generator is as a source of gamma rays for calibration of gamma ray detectors.

  5. Ultra High Mass Range Mass Spectrometer System

    DOE Patents [OSTI]

    Reilly, Peter T. A. [Knoxville, TN

    2005-12-06

    Applicant's present invention comprises mass spectrometer systems that operate in a mass range from 1 to 10.sup.16 DA. The mass spectrometer system comprising an inlet system comprising an aerodynamic lens system, a reverse jet being a gas flux generated in an annulus moving in a reverse direction and a multipole ion guide; a digital ion trap; and a thermal vaporization/ionization detector system. Applicant's present invention further comprises a quadrupole mass spectrometer system comprising an inlet system having a quadrupole mass filter and a thermal vaporization/ionization detector system. Applicant's present invention further comprises an inlet system for use with a mass spectrometer system, a method for slowing energetic particles using an inlet system. Applicant's present invention also comprises a detector device and a method for detecting high mass charged particles.

  6. X-ray Spectral Diagnostics of Gamma-Ray Burst Environments

    E-Print Network [OSTI]

    Frits Paerels; Erik Kuulkers; John Heise; Duane A. Liedahl

    2000-04-13

    Recently, the detection of discrete features in the X-ray afterglow spectra of GRB970508 and GRB970828 was reported. The most natural interpretation of these features is that they are redshifted Fe K emission complexes. The identification of the line emission mechanism has drastic implications for the inferred mass of radiating material, end hence the nature of the burst site. X-ray spectroscopy provides a direct observational constraint on these properties of gamma-ray bursters. We briefly discuss how these constraints arise, in the context of an application to the spectrum of GRB970508.

  7. Total Absorption Gamma-ray Spectrometer (TAGS) Intensity Distributions from INL's Gamma-Ray Spectrometry Center

    DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]

    Greenwood, R. E.

    A 252Cf fission-product source and the INL on-line isotope separator were used to supply isotope-separated fission-product nuclides to a total absorption -ray spectrometer. This spectrometer consisted of a large (25.4-cm diameter x 30.5-cm long) NaI(Tl) detector with a 20.3-cm deep axial well in which is placed a 300-mm2 x 1.0-mm Si detector. The spectra from the NaI(Tl) detector are collected both in the singles mode and in coincidence with the B-events detected in the Si detector. Ideally, this detector would sum all the energy of the B- rays in each cascade following the population of daughter level by B- decay, so that the event could be directly associated with a particular daughter level. However, there are losses of energy from attenuation of the rays before they reach the detector, transmission of rays through the detector, escape of secondary photons from Compton scattering, escape of rays through the detector well, internal conversion, etc., and the measured spectra are thus more complicated than the ideal case and the analysis is more complex. Analysis methods have been developed to simulate all of these processes and thus provide a direct measure of the B- intensity distribution as a function of the excitation energy in the daughter nucleus. These data yield more accurate information on the B- distribution than conventional decay-scheme studies for complex decay schemes with large decay energies, because in the latter there are generally many unobserved and observed but unplaced rays. The TAGS data have been analyzed and published [R. E. Greenwood et al., Nucl Instr. and metho. A390(1997)] for 40 fission product-nuclides to determine the B- intensity distributions. [Copied from the TAGS page at http://www.inl.gov/gammaray/spectrometry/tags.shtml]. Those values are listed on this page for quick reference.

  8. Thermal neutron capture gamma-rays

    SciTech Connect (OSTI)

    Tuli, J.K.

    1983-01-01

    The energy and intensity of gamma rays as seen in thermal neutron capture are presented. Only those (n,..cap alpha..), E = thermal, reactions for which the residual nucleus mass number is greater than or equal to 45 are included. These correspond to evaluations published in Nuclear Data Sheets. The publication source data are contained in the Evaluated Nuclear Structure Data File (ENSDF). The data presented here do not involve any additional evaluation. Appendix I lists all the residual nuclides for which the data are included here. Appendix II gives a cumulated index to A-chain evaluations including the year of publication. The capture gamma ray data are given in two tables - the Table 1 is the list of all gamma rays seen in (n,..gamma..) reaction given in the order of increasing energy; the Table II lists the gamma rays according to the nuclide.

  9. Gravitational waves and gamma-ray bursts

    E-Print Network [OSTI]

    Alessandra Corsi; for the LIGO Scientific Collaboration; for the Virgo Collaboration

    2012-05-11

    Gamma-Ray Bursts are likely associated with a catastrophic energy release in stellar mass objects. Electromagnetic observations provide important, but indirect information on the progenitor. On the other hand, gravitational waves emitted from the central source, carry direct information on its nature. In this context, I give an overview of the multi-messenger study of gamma-ray bursts that can be carried out by using electromagnetic and gravitational wave observations. I also underline the importance of joint electromagnetic and gravitational wave searches, in the absence of a gamma-ray trigger. Finally, I discuss how multi-messenger observations may probe alternative gamma-ray burst progenitor models, such as the magnetar scenario.

  10. HgMn Stars as apparent X-ray emitters

    E-Print Network [OSTI]

    Hubrig, S; Mathys, G

    1998-01-01

    In the ROSAT all-sky survey 11 HgMn stars were detected as soft X-ray emitters (Berghoefer, Schmitt & Cassinelli 1996). Prior to ROSAT, X-ray observations with the Einstein Observatory had suggested that stars in the spectral range B5-A7 are devoid of X-ray emission. Since there is no X-ray emitting mechanism available for these stars (also not for HgMn stars), the usual argument in the case of an X-ray detected star of this spectral type is the existence of an unseen low-mass companion which is responsible for the X-ray emission. The purpose of the present work is to use all available data for our sample of X-ray detected HgMn stars and conclude on the nature of possible companions.

  11. Dynamic effective mass of granular media

    E-Print Network [OSTI]

    Chaur-Jian Hsu; David L. Johnson; Rohit A. Ingale; John J. Valenza; Nicolas Gland; Hernan A. Makse

    2008-08-15

    We develop the concept of frequency dependent effective mass, M(omega), of jammed granular materials which occupy a rigid cavity to a filling fraction of 48%, the remaining volume being air of normal room condition or controlled humidity. The dominant features of M(omega) provide signatures of the dissipation of acoustic modes, elasticity and aging effects in the granular medium. We perform humidity controlled experiments and interpret the data in terms of a continuum model and a "trap" model of thermally activated capillary bridges at the contact points. The results suggest that attenuation in the granular materials is influenced significantly by the kinetics of capillary condensation between the asperities at the contacts.

  12. A model for P-wave attenuation and dispersion in a porous medium ...

    E-Print Network [OSTI]

    lll

    2005-09-05

    with a liquid this material exhibits significant attenuation and velocity dispersion ... instances, natural fractures control the permeability of the reservoir, and hence the ...... anisotropic layered fluid- and gas-saturated sediments, Geophysics, 62,.

  13. Novel Use of P- and S-Wave Seismic Attenuation for Deep Natural...

    Office of Scientific and Technical Information (OSTI)

    Technical Report: Novel Use of P- and S-Wave Seismic Attenuation for Deep Natural Gas Exploration and Development Citation Details In-Document Search Title: Novel Use of P- and...

  14. Shear wave attenuation and dispersion in melt-bearing olivine polycrystals

    E-Print Network [OSTI]

    interpretation and seismological implications Ulrich H. Faul, John D. Fitz Gerald, and Ian Jackson Research: seismic wave attenuation, olivine, partial melting, grain boundary sliding, grain boundary structure and dispersion in melt-bearing olivine polycrystals: 2. Microstructural interpretation and seismological

  15. The oceanic and cratonic upper mantle: Clues from joint interpretation of global velocity and attenuation models

    E-Print Network [OSTI]

    Asthenosphere Seismic attenuation Seismic velocity Anelasticity Partial melt Combined interpretation of seismicThe oceanic and cratonic upper mantle: Clues from joint interpretation of global velocity anelastic dispersion (Karato and Jung, 1998; Karato, 2003). A unique interpretation of seismological models

  16. An in situ measurement of the radio-frequency attenuation in ice at Summit Station, Greenland

    E-Print Network [OSTI]

    J. Avva; J. M. Kovac; C. Miki; D. Saltzberg; A. G. Vieregg

    2014-09-30

    We report an in situ measurement of the electric field attenuation length at radio frequencies for the bulk ice at Summit Station, Greenland, made by broadcasting radio-frequency signals vertically through the ice and measuring the relative power in the return ground bounce signal. We find the depth-averaged field attenuation length to be 947 +92/-85 meters at 75 MHz. While this measurement has clear radioglaciological applications, the radio clarity of the ice also has implications for the detection of ultra-high energy (UHE) astrophysical particles via their radio emission in dielectric media such as ice. The measured attenuation length at Summit Station is comparable to previously measured radio-frequency attenuation lengths at candidate particle detector sites around the world, and strengthens the case for Summit Station as the most promising northern site for UHE neutrino detection.

  17. An in situ measurement of the radio-frequency attenuation in ice at Summit Station, Greenland

    E-Print Network [OSTI]

    J. Avva; J. M. Kovac; C. Miki; D. Saltzberg; A. G. Vieregg

    2015-12-02

    We report an in situ measurement of the electric field attenuation length at radio frequencies for the bulk ice at Summit Station, Greenland, made by broadcasting radio-frequency signals vertically through the ice and measuring the relative power in the return ground bounce signal. We find the depth-averaged field attenuation length to be 947 +92/-85 meters at 75 MHz. While this measurement has clear radioglaciological applications, the radio clarity of the ice also has implications for the detection of ultra-high energy (UHE) astrophysical particles via their radio emission in dielectric media such as ice. Assuming a reliable extrapolation to higher frequencies, the measured attenuation length at Summit Station is comparable to previously measured radio-frequency attenuation lengths at candidate particle detector sites around the world, and strengthens the case for Summit Station as a promising northern site for UHE neutrino detection.

  18. Multivariate analysis of cross-hole georadar velocity and attenuation tomograms for aquifer zonation

    E-Print Network [OSTI]

    Barrash, Warren

    Multivariate analysis of cross-hole georadar velocity and attenuation tomograms for aquifer for characterizing heterogeneous alluvial aquifers. A multivariate statistical technique, known as k-means cluster radar, multivariate statistics, unconfined aquifers Citation: Tronicke, J., K. Holliger, W. Barrash

  19. Endogenous opioids and attenuated hypothalamic-pituitary-adrenal axis responses to immune challenge in pregnant rats 

    E-Print Network [OSTI]

    Russell, J. A.; Ochedalski, T; Meddle, S. L.; Ma, S.; Brunton, P. J.; Douglas, A. J.

    2005-01-01

    In late pregnant rats, the hypothalamic-pituitary-adrenal (HPA) axis is hyporesponsive to psychogenic stressors. Here, we investigated attenuated HPA responses to an immune challenge and a role for endogenous opioids. ACTH ...

  20. Galactic modulation of extragalactic cosmic rays -Alternative scenario of the origin of the knee -

    E-Print Network [OSTI]

    Galactic modulation of extragalactic cosmic rays - Alternative scenario of the origin of the knee is reproduced well again. The energy dependence of mean mass of cosmic rays above the knee energy is presented to be compared with observations. . 1. Introduction Cosmic rays (CRs) with energies below the knee have been

  1. Frequency-dependent attenuation and elasticity in unconsolidated earth materials: effect of damping

    E-Print Network [OSTI]

    Yanqing Hu; Hernán A. Makse; John J. Valenza; David L. Johnson

    2014-10-20

    We use the Discrete Element Method (DEM) to understand the underlying attenuation mechanism in granular media, with special applicability to the measurements of the so-called effective mass developed earlier. We consider that the particles interact via Hertz-Mindlin elastic contact forces and that the damping is describable as a force proportional to the velocity difference of contacting grains. We determine the behavior of the complex-valued normal mode frequencies using 1) DEM, 2) direct diagonalization of the relevant matrix, and 3) a numerical search for the zeros of the relevant determinant. All three methods are in strong agreement with each other. The real and the imaginary parts of each normal mode frequency characterize the elastic and the dissipative properties, respectively, of the granular medium. We demonstrate that, as the interparticle damping, $\\xi$, increases, the normal modes exhibit nearly circular trajectories in the complex frequency plane and that for a given value of $\\xi$ they all lie on or near a circle of radius $R$ centered on the point $-iR$ in the complex plane, where $R\\propto 1/\\xi$. We show that each normal mode becomes critically damped at a value of the damping parameter $\\xi \\approx 1/\\omega_n^0$, where $\\omega_n^0$ is the (real-valued) frequency when there is no damping. The strong indication is that these conclusions carry over to the properties of real granular media whose dissipation is dominated by the relative motion of contacting grains. For example, compressional or shear waves in unconsolidated dry sediments can be expected to become overdamped beyond a critical frequency, depending upon the strength of the intergranular damping constant.

  2. Mass spectrometric immunoassay

    DOE Patents [OSTI]

    Nelson, Randall W (Phoenix, AZ); Williams, Peter (Phoenix, AZ); Krone, Jennifer Reeve (Granbury, TX)

    2007-12-04

    Rapid mass spectrometric immunoassay methods for detecting and/or quantifying antibody and antigen analytes utilizing affinity capture to isolate the analytes and internal reference species (for quantification) followed by mass spectrometric analysis of the isolated analyte/internal reference species. Quantification is obtained by normalizing and calibrating obtained mass spectrum against the mass spectrum obtained for an antibody/antigen of known concentration.

  3. Attenuation of acoustic waves in glacial ice and salt domes

    E-Print Network [OSTI]

    P. B. Price

    2005-06-27

    Two classes of natural solid media (glacial ice and salt domes) are under consideration as media in which to deploy instruments for detection of neutrinos with energy >1e18 eV. Though insensitive to 1e11 to 1e16 eV neutrinos for which observatories (e.g., AMANDA and IceCube) that utilize optical Cherenkov radiation detectors are designed, radio and acoustic methods are suited for searches for the very low fluxes of neutrinos with energies >1017 eV. This is because, due to the very long attenuation lengths of radio and acoustic waves in ice and salt, detection modules can be spaced very far apart. In this paper, I calculate the absorption and scattering coefficients as a function of frequency and grain size for acoustic waves in glacial ice and salt domes and show that experimental measurements on laboratory samples and in glacial ice and salt domes are consistent with theory. For South Pole ice with grain size 0.2 cm at -51 degrees C, scattering lengths are calculated to be 2000 km and 25 km at 10 kHz and 30 kHz, respectively, and the absorption length is calculated to be 9 km at frequencies above 100 Hz. For NaCl (rock salt) with grain size 0.75 cm, scattering lengths are calculated to be 120 km and 1.4 km at 10 kHz and 30 kHz, and absorption lengths are calculated to be 30,000 km and 3300 km at 10 kHz and 30 kHz. Existing measurements are consistent with theory. For ice, absorption is the limiting factor; for salt, scattering is the limiting factor.

  4. Natural attenuation of metals and radionuclides: Report from a workshop held by Sandia National Laboratories

    SciTech Connect (OSTI)

    Brady, P.V.; Borns, D.J. [Sandia National Labs., Albuquerque, NM (United States). Geochemistry Dept.

    1997-11-01

    Natural attenuation is increasingly applied to remediate contaminated soils and ground waters. Roughly 25% of Superfund groundwater remedies in 1995 involved some type of monitored natural attenuation, compared to almost none 5 years ago. Remediation by natural attenuation (RNA) requires clear evidence that contaminant levels are decreasing sufficiently over time, a defensible explanation of the attenuation mechanism, long-term monitoring, and a contingency plan at the very least. Although the primary focus of implementation has to date been the biodegradation of organic contaminants, there is a wealth of scientific evidence that natural processes reduce the bioavailability of contaminant metals and radionuclides. Natural attenuation of metals and radionuclides is likely to revolve around sorption, solubility, biologic uptake and dilution controls over contaminant availability. Some of these processes can be applied to actively remediate sites. Others, such as phytoremediation, are likely to be ineffective. RNA of metals and radionuclides is likely to require specialized site characterization to construct contaminant and site-specific conceptual models of contaminant behavior. Ideally, conceptual models should be refined such that contaminant attenuation can be confidently predicted into the future. The technical approach to RNA of metals and radionuclides is explored here.

  5. Study of transmission line attenuation in broad band millimeter wave frequency range

    SciTech Connect (OSTI)

    Pandya, Hitesh Kumar B.; Austin, M. E.; Ellis, R. F.

    2013-10-15

    Broad band millimeter wave transmission lines are used in fusion plasma diagnostics such as electron cyclotron emission (ECE), electron cyclotron absorption, reflectometry and interferometry systems. In particular, the ECE diagnostic for ITER will require efficient transmission over an ultra wide band, 100 to 1000 GHz. A circular corrugated waveguide transmission line is a prospective candidate to transmit such wide band with low attenuation. To evaluate this system, experiments of transmission line attenuation were performed and compared with theoretical loss calculations. A millimeter wave Michelson interferometer and a liquid nitrogen black body source are used to perform all the experiments. Atmospheric water vapor lines and continuum absorption within this band are reported. Ohmic attenuation in corrugated waveguide is very low; however, there is Bragg scattering and higher order mode conversion that can cause significant attenuation in this transmission line. The attenuation due to miter bends, gaps, joints, and curvature are estimated. The measured attenuation of 15 m length with seven miter bends and eighteen joints is 1 dB at low frequency (300 GHz) and 10 dB at high frequency (900 GHz), respectively.

  6. Polarization mesurements of gamma ray bursts and axion like particles

    E-Print Network [OSTI]

    Andre Rubbia; Alexander Sakharov

    2008-09-03

    A polarized gamma ray emission spread over a sufficiently wide energy band from a strongly magnetized astrophysical object like gamma ray bursts (GRBs) offers an opportunity to test the hypothesis of axion like particles (ALPs). Based on evidences of polarized gamma ray emission detected in several gamma ray bursts we estimated the level of ALPs induced dichroism, which could take place in the magnetized fireball environment of a GRB. This allows to estimate the sensitivity of polarization measurements of GRBs to the ALP-photon coupling. This sensitivity $\\gag\\le 2.2\\cdot 10^{-11} {\\rm GeV^{-1}}$ calculated for the ALP mass $m_a=10^{-3}~{\\rm eV}$ and MeV energy spread of gamma ray emission is competitive with the sensitivity of CAST and becomes even stronger for lower ALPs masses.

  7. IMPLICATIONS OF MASS AND ENERGY LOSS DUE TO CORONAL MASS EJECTIONS ON MAGNETICALLY ACTIVE STARS

    SciTech Connect (OSTI)

    Drake, Jeremy J.; Cohen, Ofer; Yashiro, Seiji; Gopalswamy, Nat

    2013-02-20

    Analysis of a database of solar coronal mass ejections (CMEs) and associated flares over the period 1996-2007 finds well-behaved power-law relationships between the 1-8 A flare X-ray fluence and CME mass and kinetic energy. We extrapolate these relationships to lower and higher flare energies to estimate the mass and energy loss due to CMEs from stellar coronae, assuming that the observed X-ray emission of the latter is dominated by flares with a frequency as a function of energy dn/dE = kE {sup -{alpha}}. For solar-like stars at saturated levels of X-ray activity, the implied losses depend fairly weakly on the assumed value of {alpha} and are very large: M-dot {approx}5 Multiplication-Sign 10{sup -10} M{sub sun} yr{sup -1} and E-dot {approx}0.1 L{sub sun}. In order to avoid such large energy requirements, either the relationships between CME mass and speed and flare energy must flatten for X-ray fluence {approx}> 10{sup 31} erg, or the flare-CME association must drop significantly below 1 for more energetic events. If active coronae are dominated by flares, then the total coronal energy budget is likely to be up to an order of magnitude larger than the canonical 10{sup -3} L {sub bol} X-ray saturation threshold. This raises the question of what is the maximum energy a magnetic dynamo can extract from a star? For an energy budget of 1% of L {sub bol}, the CME mass loss rate is about 5 Multiplication-Sign 10{sup -11} M {sub Sun} yr{sup -1}.

  8. Parallel Seismic Ray Tracing 

    E-Print Network [OSTI]

    Jain, Tarun K

    2013-12-09

    the idea of modeling ray tubes with an additional ray in the center to facilitate parallelism. The parallel wavefront construction algorithm is applied to wide range of models such as simple synthetic models that enable us to study various aspects...

  9. Ray J. Corey- Biography

    Broader source: Energy.gov [DOE]

    Ray Corey currently serves as the Assistance Manager for Safety and Environment at the DOE Richland Operations office (RL).

  10. Oscillations During Thermonuclear X-ray Bursts

    E-Print Network [OSTI]

    Tod E. Strohmayer

    2001-01-12

    High amplitude, nearly coherent X-ray brightness oscillations during thermonuclear X-ray bursts were discovered with the Rossi X-ray Timing Explorer (RXTE) in early 1996. Spectral and timing evidence strongly supports the conclusion that these oscillations are caused by rotational modulation of the burst emission and that they reveal the spin frequency of neutron stars in low mass X-ray binaries, a long sought goal of X-ray astronomy. Studies carried out over the past year have led to the discovery of burst oscillations in four new sources, bringing to ten the number with confirmed burst oscillations. I review the status of our knowledge of these oscillations and indicate how they can be used to probe the physics of neutron stars. For a few burst oscillation sources it has been proposed that the strongest and most ubiquitous frequency is actually the first overtone of the spin frequency and hence that two nearly antipodal hot spots are present on the neutron star. This inference has important implications for both the physics of thermonuclear burning as well as the mass - radius relation for neutron stars, so its confirmation is crucial. I discuss recent attempts to confirm this hypothesis for 4U 1636-53, the source for which a signal at the putative fundamental (290 Hz) has been claimed.

  11. NEUTRINO-COOLED ACCRETION MODEL WITH MAGNETIC COUPLING FOR X-RAY FLARES IN GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Luo Yang; Gu Weimin; Liu Tong; Lu Jufu, E-mail: guwm@xmu.edu.cn [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China)

    2013-08-20

    The neutrino-cooled accretion disk, which was proposed to work as the central engine of gamma-ray bursts, encounters difficulty in interpreting the X-ray flares after the prompt gamma-ray emission. In this paper, the magnetic coupling (MC) between the inner disk and the central black hole (BH) is taken into consideration. For mass accretion rates around 0.001 {approx} 0.1 M{sub Sun} s{sup -1}, our results show that the luminosity of neutrino annihilation can be significantly enhanced due to the coupling effects. As a consequence, after the gamma-ray emission, a remnant disk with mass M{sub disk} {approx}< 0.5 M{sub Sun} may power most of the observed X-ray flares with the rest frame duration less than 100 s. In addition, a comparison between the MC process and the Blandford-Znajek mechanism is shown on the extraction of BH rotational energy.

  12. Improving Earthquake-Explosion Discrimination using Attenuation Models of the Crust and Upper Mantle

    SciTech Connect (OSTI)

    Pasyanos, M E; Walter, W R; Matzel, E M; Rodgers, A J; Ford, S R; Gok, R; Sweeney, J J

    2009-07-06

    In the past year, we have made significant progress on developing and calibrating methodologies to improve earthquake-explosion discrimination using high-frequency regional P/S amplitude ratios. Closely-spaced earthquakes and explosions generally discriminate easily using this method, as demonstrated by recordings of explosions from test sites around the world. In relatively simple geophysical regions such as the continental parts of the Yellow Sea and Korean Peninsula (YSKP) we have successfully used a 1-D Magnitude and Distance Amplitude Correction methodology (1-D MDAC) to extend the regional P/S technique over large areas. However in tectonically complex regions such as the Middle East, or the mixed oceanic-continental paths for the YSKP the lateral variations in amplitudes are not well predicted by 1-D corrections and 1-D MDAC P/S discrimination over broad areas can perform poorly. We have developed a new technique to map 2-D attenuation structure in the crust and upper mantle. We retain the MDAC source model and geometrical spreading formulation and use the amplitudes of the four primary regional phases (Pn, Pg, Sn, Lg), to develop a simultaneous multi-phase approach to determine the P-wave and S-wave attenuation of the lithosphere. The methodology allows solving for attenuation structure in different depth layers. Here we show results for the P and S-wave attenuation in crust and upper mantle layers. When applied to the Middle East, we find variations in the attenuation quality factor Q that are consistent with the complex tectonics of the region. For example, provinces along the tectonically-active Tethys collision zone (e.g. Turkish Plateau, Zagros) have high attenuation in both the crust and upper mantle, while the stable outlying regions like the Indian Shield generally have low attenuation. In the Arabian Shield, however, we find that the low attenuation in this Precambrian crust is underlain by a high-attenuation upper mantle similar to the nearby Red Sea Rift. Applying this 2-D MDAC methodology with the new attenuation models can significantly improve earthquake-explosion discrimination using regional P/S amplitude ratios. We demonstrate applications of this technique, including a study at station NIL (Nilore, Pakistan) using broad area earthquakes and the 1998 Indian nuclear explosion using a number of regional amplitude ratio discriminants. We are currently applying the technique in the YSKP region as well.

  13. Gamma Rays from Clusters and Groups of Galaxies: Cosmic Rays versus Dark Matter

    E-Print Network [OSTI]

    Tesla E. Jeltema; John Kehayias; Stefano Profumo

    2009-05-22

    Clusters of galaxies have not yet been detected at gamma-ray frequencies; however, the recently launched Fermi Gamma-ray Space Telescope, formerly known as GLAST, could provide the first detections in the near future. Clusters are expected to emit gamma rays as a result of (1) a population of high-energy primary and re-accelerated secondary cosmic rays (CR) fueled by structure formation and merger shocks, active galactic nuclei and supernovae, and (2) particle dark matter (DM) annihilation. In this paper, we ask the question of whether the Fermi telescope will be able to discriminate between the two emission processes. We present data-driven predictions for a large X-ray flux limited sample of galaxy clusters and groups. We point out that the gamma ray signals from CR and DM can be comparable. In particular, we find that poor clusters and groups are the systems predicted to have the highest DM to CR emission at gamma-ray energies. Based on detailed Fermi simulations, we study observational handles that might enable us to distinguish the two emission mechanisms, including the gamma-ray spectra, the spatial distribution of the signal and the associated multi-wavelength emissions. We also propose optimal hardness ratios, which will help to understand the nature of the gamma-ray emission. Our study indicates that gamma rays from DM annihilation with a high particle mass can be distinguished from a CR spectrum even for fairly faint sources. Discriminating a CR spectrum from a light DM particle will be instead much more difficult, and will require long observations and/or a bright source. While the gamma-ray emission from our simulated clusters is extended, determining the spatial distribution with Fermi will be a challenging task requiring an optimal control of the backgrounds.

  14. Mechanical loading attenuates loss of bone mass and bone strength induced by immobilization and calcium-deficiency 

    E-Print Network [OSTI]

    Inman, Cynthia Lynn

    1996-01-01

    Immobilization and calcium-deficiency have been documented to cause a decrease in strength and bone mineral loss, and exercise is known to strengthen bone. The purpose of this study was to determine the effects of mechanical ...

  15. X-ray properties of UV-selected star forming galaxies at z~1 in the Hubble Deep Field North

    E-Print Network [OSTI]

    Laird, E S; Adelberger, K L; Steidel, C C; Reddy, N A

    2005-01-01

    We present an analysis of the X-ray emission from a large sample of ultraviolet (UV) selected, star forming galaxies with 0.74ray emission in the 2 Ms Chandra observation we are able to examine the properties of galaxies for which the emission in both UV and X-ray is expected to be predominantly due to star formation. Stacking the X-ray flux from 216 galaxies in the soft and hard bands produces significant detections. The derived mean 2-10 keV rest-frame luminosity is 2.97+/-0.26x10^(40) erg/s, corresponding to an X-ray derived star formation rate (SFR) of 6.0+/-0.6 Msolar/yr. Comparing the X-ray value with the mean UV derived SFR, uncorrected for attenuation, we find that the average UV attenuation correction factor is \\~3. By binning the galaxy sample according to UV magnitude and colour, correlations between UV and X-ray emission are also examined. We find a strong positive correlation between ...

  16. Delayed Nickel Decay in Gamma Ray Bursts

    E-Print Network [OSTI]

    G. C. McLaughlin; R. A. M. J. Wijers

    2002-05-19

    Recently observed emission lines in the X-ray afterglow of gamma ray bursts suggest that iron group elements are either produced in the gamma ray burst, or are present nearby. If this material is the product of a thermonuclear burn, then such material would be expected to be rich in Nickel-56. If the nickel remains partially ionized, this prevents the electron capture reaction normally associated with the decay of Nickel-56, dramatically increasing the decay timescale. Here we examine the consequences of rapid ejection of a fraction of a solar mass of iron group material from the center of a collapsar/hypernova. The exact rate of decay then depends on the details of the ionization and therefore the ejection process. Future observations of iron, nickel and cobalt lines can be used to diagnose the origin of these elements and to better understand the astrophysical site of gamma ray bursts. In this model, the X-ray lines of these iron-group elements could be detected in suspected hypernovae that did not produce an observable gamma ray burst due to beaming.

  17. Elbow mass flow meter

    DOE Patents [OSTI]

    McFarland, Andrew R. (College Station, TX); Rodgers, John C. (Santa Fe, NM); Ortiz, Carlos A. (Bryan, TX); Nelson, David C. (Santa Fe, NM)

    1994-01-01

    Elbow mass flow meter. The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity.

  18. Monitored Natural Attenuation of ino9rganic Contaminants Treatability Study Final Report

    SciTech Connect (OSTI)

    Crapse, K

    2004-05-19

    The identification and quantification of key natural attenuation processes for inorganic contaminants at D-Area is detailed herein. Two overarching goals of this evaluation of monitored natural attenuation (MNA) as a remediation strategy were (1) to better define the availability of inorganic contaminants as potential sources for transport to groundwater and uptake by environmental receptors and (2) to understand the site-specific mechanisms controlling attenuation of these inorganic contaminants through tandem geochemical and biological characterization. Data collected in this study provides input for more appropriate site groundwater transport models. Significant natural attenuation is occurring at D-Area as evidenced by relatively low aqueous concentrations of constituents of concern (COCs) (Be, Ni, U, and As) at all locations characterized and the decrease in groundwater concentrations with increasing distance from the source. The observed magnitude of decrease in groundwater concentrations of COCs with distance from the D-Area Coal Pile Runoff Basin (DCPRB) could not be accounted for by the modeled physical attenuation processes of dilution/dispersion. This additional attenuation, i.e., the observed difference between the groundwater concentrations of COCs and the modeled physical attenuation, is due to biogeochemical processes occurring at the D-Area. In tandem geochemical and microbiological characterization studies designed to evaluate the mechanisms contributing to natural attenuation, pH was the single parameter found to be most predictive of contaminant attenuation. The increasing pH with distance from the source is likely responsible for increased sorption of COCs to soil surfaces within the aquifer at D-Area. Importantly, because the sediments appear to have a high buffering capacity, the acid emanating from the DCPRB has been neutralized by the soil, and these conditions have led to large Kd values at the site. Two major types of soils are present at D-Area and were evaluated in this study: upland subsurface soils associated with a low pH/high sulfate/metals plume down-gradient of the D-Area Coal Pile Runoff Basin (DCPRB) and surface ash material discharged to the wetland from the D-Area Ash Basin (488-D). Sequential extraction studies were carried out to better define the availability of inorganic contaminant sources at D-Area.

  19. THE SCENARIOS APPROACH TO ATTENUATION-BASED REMEDIES FOR INORGANIC AND RADIONUCLIDE CONTAMINANTS

    SciTech Connect (OSTI)

    Vangelas, K.; Rysz, M.; Truex, M.; Brady, P.; Newell, C.; Denham, M.

    2011-08-04

    Guidance materials based on use of conceptual model scenarios were developed to assist evaluation and implementation of attenuation-based remedies for groundwater and vadose zones contaminated with inorganic and radionuclide contaminants. The Scenarios approach is intended to complement the comprehensive information provided in the US EPA's Technical Protocol for Monitored Natural Attenuation (MNA) of Inorganic Contaminants by providing additional information on site conceptual models and extending the evaluation to consideration of Enhanced Attenuation approaches. The conceptual models incorporate the notion of reactive facies, defined as units with hydrogeochemical properties that are different from surrounding units and that react with contaminants in distinct ways. The conceptual models also incorporate consideration of biogeochemical gradients, defined as boundaries between different geochemical conditions that have been induced by waste disposal or other natural phenomena. Gradients can change over time when geochemical conditions from one area migrate into another, potentially affecting contaminant mobility. A recognition of gradients allows the attenuation-affecting conditions of a site to be projected into the future. The Scenarios approach provides a stepwise process to identify an appropriate category of conceptual model and refine it for a specific site. Scenario materials provide links to pertinent sections in the EPA technical protocol and present information about contaminant mobility and important controlling mechanism for attenuation-based remedies based on the categories of conceptual models.

  20. X-ray emission properties of galaxies in Abell 3128

    E-Print Network [OSTI]

    Russell J. Smith

    2003-07-15

    We use archival Chandra X-ray Observatory data to investigate X-ray emission from early-type galaxies in the rich z=0.06 cluster Abell 3128. By combining the X-ray count-rates from an input list of optically-selected galaxies, we obtain a statistical detection of X-ray flux, unbiased by X-ray selection limits. Using 87 galaxies with reliable Chandra data, X-ray emission is detected for galaxies down to M_B ~ -19.0, with only an upper limit determined for galaxies at M_B ~ -18.3. The ratio of X-ray to optical luminosities is consistent with recent determinations of the low-mass X-ray binary content of nearby elliptical galaxies. Taken individually, in contrast, we detect significant (3sigma) flux for only six galaxies. Of these, one is a foreground galaxy, while two are optically-faint galaxies with X-ray hardness ratios characteristic of active galactic nuclei. The remaining three detected galaxies are amongst the optically-brightest cluster members, and have softer X-ray spectra. Their X-ray flux is higher than that expected from X-ray binaries, by a factor 2-10; the excess suggests these galaxies have retained their hot gaseous haloes. The source with the highest L_X / L_B ratio is of unusual optical morphology with prominent sharp-edged shells. Notwithstanding these few exceptions, the cluster population overall exhibits X-ray properties consistent with their emission being dominated by X-ray binaries. We conclude that in rich cluster environments, interaction with the ambient intra-cluster medium acts to strip most galaxies of their hot halo gas.

  1. Simulation of e-cloud driven instability and its attenuation using a simulated feedback system in the CERN SPS

    E-Print Network [OSTI]

    Vay, J.-L.

    2011-01-01

    system for the attenuation of e-cloud driven instability”, Proceed- ings Particle Acceleratorsystem for electron cloud-driven instabilities in the CERN SPS”, Proceedings Particle Accelerator

  2. The Administration of Intranasal Live Attenuated Influenza Vaccine Induces Changes in the Nasal Microbiota and Nasal Epithelium Gene Expression Profile

    E-Print Network [OSTI]

    Tarabichi, Yasir

    2015-01-01

    56 vi The Administration of Intranasal Live AttenuatedCALIFORNIA Los Angeles The Administration of Intranasal LiveABSTRACT OF THE THESIS The Administration of Intranasal Live

  3. Neutrino Majorana Mass from Black Hole

    E-Print Network [OSTI]

    Yosuke Uehara

    2002-05-25

    We propose a new mechanism to generate the neutrino Majorana mass in TeV-scale gravity models. The black hole violates all non-gauged symmetries and can become the origin of lepton number violating processes. The fluctuation of higher-dimensional spacetime can result in the production of a black hole, which emits 2 neutrinos. If neutrinos are Majorana particles, this process is equivalent to the free propagation of a neutrino with the insertion of the black hole. From this fact, we derive the neutrino Majorana mass. The result is completely consistent with the recently observed evidence of neutrinoless double beta decay. And the obtained neutrino Majorana mass satisfies the constraint from the density of the neutrino dark matter, which affects the cosmic structure formation. Furthermore, we can explain the ultrahigh energy cosmic rays by the Z-burst scenario with it.

  4. Gamma-Ray Bursts

    E-Print Network [OSTI]

    E. Waxman

    2000-04-11

    Ultra-high-energy, >10^19 eV, cosmic-ray and high energy, ~10^14 eV, neutrino production in GRBs is discussed in the light of recent GRB and cosmic-ray observations. Emphasis is put on model predictions that can be tested with operating and planned cosmic-ray and neutrino detectors, and on the prospects of testing for neutrino properties.

  5. 3-D seismic velocity and attenuation structures in the geothermal field

    SciTech Connect (OSTI)

    Nugraha, Andri Dian [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Global Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Syahputra, Ahmad [Geophyisical Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Geophyisical Engineering, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia); Fatkhan,; Sule, Rachmat [Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)] [Applied Geophysics Research Group, Faculty of Mining and Petroleum Engineering, Institute of Technology Bandung, Jalan Ganesha No. 10 Bandung, 40132 (Indonesia)

    2013-09-09

    We conducted delay time tomography to determine 3-D seismic velocity structures (Vp, Vs, and Vp/Vs ratio) using micro-seismic events in the geothermal field. The P-and S-wave arrival times of these micro-seismic events have been used as input for the tomographic inversion. Our preliminary seismic velocity results show that the subsurface condition of geothermal field can be fairly delineated the characteristic of reservoir. We then extended our understanding of the subsurface physical properties through determining of attenuation structures (Qp, Qs, and Qs/Qp ratio) using micro-seismic waveform. We combined seismic velocities and attenuation structures to get much better interpretation of the reservoir characteristic. Our preliminary attanuation structures results show reservoir characterization can be more clearly by using the 3-D attenuation model of Qp, Qs, and Qs/Qp ratio combined with 3-D seismic velocity model of Vp, Vs, and Vp/Vs ratio.

  6. Gamma Ray Bursts Sudden, intense flashes of gamma rays

    E-Print Network [OSTI]

    Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

    Gamma Ray Bursts #12;The Case Sudden, intense flashes of gamma rays come from nowhere and disappear with out a trace. Incredibly powerful: A single gamma ray burst is hundreds of times brighter a supernova #12;Who Vela (1960's) Looking for arms testing, found gamma ray bursts Compton Gamma Ray Observatory

  7. Chest x-Rays

    Broader source: Energy.gov [DOE]

    The B-reading is a special reading of a standard chest x-ray film performed by a physician certified by the National Institute for Occupational Safety and Health (NIOSH). The reading looks for changes on the chest x-ray that may indicate exposure and disease caused by agents such as asbestos or silica.

  8. Gamma Ray Bursts

    E-Print Network [OSTI]

    Peter Mészáros

    2012-04-12

    Gamma-ray bursts have been detected at photon energies up to tens of GeV. We review some recent developments in the X-ray to GeV photon phenomenology in the light of Swift and Fermi observations, and some of the theoretical models developed to explain them, with a view towards implications for C.T.A.

  9. X-ray beamsplitter

    DOE Patents [OSTI]

    Ceglio, Natale M. (Livermore, CA); Stearns, Daniel S. (Mountain View, CA); Hawryluk, Andrew M. (Modesto, CA); Barbee, Jr., Troy W. (Palo Alto, CA)

    1989-01-01

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

  10. X-ray beamsplitter

    DOE Patents [OSTI]

    Ceglio, N.M.; Stearns, D.G.; Hawryluk, A.M.; Barbee, T.W. Jr.

    1987-08-07

    An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5--50 pairs of alternate Mo/Si layers with a period of 20--250 A. The support membrane is 10--200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window. 6 figs.

  11. Light Quark Mass Reweighting

    E-Print Network [OSTI]

    Qi Liu; Norman H. Christ; Chulwoo Jung

    2012-06-01

    We present a systematic study of the effectiveness of light quark mass reweighting. This method allows a single lattice QCD ensemble, generated with a specific value of the dynamical light quark mass, to be used to determine results for other, nearby light dynamical quark masses. We study two gauge field ensembles generated with 2+1 flavors of dynamical domain wall fermions with light quark masses m_l=0.02 (m_\\pi=620 MeV) and m_l=0.01 (m_\\pi=420 MeV). We reweight each ensemble to determine results which could be computed directly from the other and check the consistency of the reweighted results with the direct results. The large difference between the 0.02 and 0.01 light quark masses suggests that this is an aggressive application of reweighting as can be seen from fluctuations in the magnitude of the reweighting factor by four orders of magnitude. Never-the-less, a comparison of the reweighed topological charge, average plaquette, residual mass, pion mass, pion decay constant, and scalar correlator between these two ensembles shows agreement well described by the statistical errors. The issues of the effective number of configurations and finite sample size bias are discussed. An examination of the topological charge distribution implies that it is more favorable to reweight from heavier mass to lighter quark mass.

  12. Nuclear Masses in Astrophysics

    E-Print Network [OSTI]

    Christine Weber; Klaus Blaum; Hendrik Schatz

    2008-12-09

    Among all nuclear ground-state properties, atomic masses are highly specific for each particular combination of N and Z and the data obtained apply to a variety of physics topics. One of the most crucial questions to be addressed in mass spectrometry of unstable radionuclides is the one of understanding the processes of element formation in the Universe. To this end, accurate atomic mass values of a large number of exotic nuclei participating in nucleosynthesis are among the key input data in large-scale reaction network calculations. In this paper, a review on the latest achievements in mass spectrometry for nuclear astrophysics is given.

  13. Multiple mass solvers

    E-Print Network [OSTI]

    B. Jegerlehner

    1997-08-29

    We present a general method to construct multiple mass solvers from standard algorithms. As an example, the BiCGstab-M algorithm is derived.

  14. Dust attenuation in z $\\sim$ 1 galaxies from Herschel and 3D-HST H$\\alpha$ measurements

    E-Print Network [OSTI]

    Puglisi, A; Franceschini, A; Talia, M; Cimatti, A; Baronchelli, I; Daddi, E; Renzini, A; Schawinski, K; Mancini, C; Silverman, J; Gruppioni, C; Lutz, D; Berta, S; Oliver, S J

    2015-01-01

    We combined the spectroscopic information from the 3D-HST survey with the PEP/Herschel data to characterize the H\\alpha dust attenuation properties of a sample of 79 normal star-forming galaxies at $0.7\\leq z\\leq1.5$ in the GOODS-S field. The sample was selected in the far-IR, at \\lambda=100 and/or 160 \\mu m, and only includes galaxies with a secure H\\alpha detection (S/N>3). From the low resolution 3D-HST spectra we measured z and F(H\\alpha) for the whole sample, rescaling the observed flux by a constant factor of 1.2 to remove the contamination by [NII]. The stellar masses, infrared and UV luminosities were derived from the SEDs by fitting multi-band data from GALEX near-UV to SPIRE500 \\mu m. We derived the continuum extinction Estar(B-V) from both the IRX ratio and the UV-slope, and found an excellent agreement among them. Galaxies in the sample have 2.6x10^9$\\leq$M*$\\leq$3.5x10^11 Msun, intense infrared luminosity (L_IR>1.2x10^10 Lsun), high level of dust obscuration (0.1$\\leq$Estar(B-V)$\\leq$1.1) and str...

  15. LeS D.4 Monitored Natural Attenuation -3 ENA OF HETEROCYCLIC HYDROCARBONS BY ADDING HYDROGEN PEROXIDE IN GROUND-

    E-Print Network [OSTI]

    Cirpka, Olaf Arie

    LeS D.4 Monitored Natural Attenuation - 3 ENA OF HETEROCYCLIC HYDROCARBONS BY ADDING HYDROGEN.troetschler@iws.uni-stuttgart.de Keywords: Enhanced Natural Attenuation, Aerobic Biological Degradation, Heterocyclic Hydro- carbons, PAH, Field Trial, Groundwater Circulation Wells (GCW) 1 Introduction Heterocyclic Hydrocarbons (NSO

  16. Shedding light on processes that control particle export and flux attenuation in the twilight zone of the open ocean

    E-Print Network [OSTI]

    Buesseler, Ken

    Shedding light on processes that control particle export and flux attenuation in the twilight zone and low surface export and subsurface flux attenuation. The ocean's ``twilight zone'' is defined). Sediment traps allowed assess- ment of the relationship among surface algal productivity, particle export

  17. Velocity and Attenuation Structure of the Tibetan Lithosphere Under the Hi-CLIMB Array From the Modeling of Pn Attributes

    E-Print Network [OSTI]

    Nowack, Robert L.

    Velocity and Attenuation Structure of the Tibetan Lithosphere Under the Hi-CLIMB Array From earthquakes in Tibet recorded by the Hi-CLIMB experiment, Pn attributes are used to constrain the velocity gradient and attenuation structure of the Tibetan lithosphere under the Hi-CLIMB array. Numerical modeling

  18. Modeling the natural attenuation of benzene in groundwater impacted by ethanol-blended fuels: Effect of ethanol content

    E-Print Network [OSTI]

    Alvarez, Pedro J.

    -source simulations imply that high-ethanol blends (e.g., E85) pose a lower risk of benzene reaching a receptor via gasoline, 15 years for E10, 9 years for E50, and 3 years for E85), indicating greater natural attenuationModeling the natural attenuation of benzene in groundwater impacted by ethanol-blended fuels

  19. Technical Evaluation Report "ND2 Attenuation of the COS Bright Object Aperture"

    E-Print Network [OSTI]

    Colorado at Boulder, University of

    Technical Evaluation Report "ND2 Attenuation of the COS Bright Object Aperture" Date: 30 June 2000 Document Number: COS-11-0019 Revision: Initial Release Contract No.: NAS5-98043 CDRL No.: N/A Prepared By: J. Morse, COS Project Scientist, CU/CASA Date Reviewed By: J. Green, COS Principal Investigator, CU

  20. NOISE SOURCE LOCALIZATION IN AN ATTENUATING MEDIUM HABIB AMMARI, ELIE BRETIN, JOSSELIN GARNIER, AND ABDUL WAHAB

    E-Print Network [OSTI]

    Garnier, Josselin

    NOISE SOURCE LOCALIZATION IN AN ATTENUATING MEDIUM HABIB AMMARI, ELIE BRETIN, JOSSELIN GARNIER of noise sources from boundary measurements using cross correlation techniques. We consider media where the noise sources are spatially correlated. We present numerical results to show the viability

  1. Computers & Geosciences 29 (2003) 351359 A case against Kd-based transport models: natural attenuation

    E-Print Network [OSTI]

    Zhu, Chen

    2003-01-01

    attenuation at a mill tailings site Chen Zhu* Department of Geology and Planetary Science, University)-based transport model. The study site is a contaminated groundwater aquifer underneath a uranium mill tailings pond in the western USA. Advective­dispersive­reactive transport is simulated for a 5-year period

  2. Estimating attenuation properties of bentonite layer in Cut Bank oil field, Glacier County, Montana 

    E-Print Network [OSTI]

    Karakurt, Necdet

    2006-04-12

    -8 to analyze the formation structure in depth, since seismic signals around the reservoir area were unclear in the 3-D survey. This research attempts to estimate the attenuation properties of the Bentonite layer in the Cut Bank oil field. VSP data is processed...

  3. Hydrogeologic assessment of in situ natural attenuation in a controlled field experiment

    E-Print Network [OSTI]

    Devlin, John F.; McMaster, M.; Barker, J. F.

    2002-01-16

    An experiment to investigate the natural attenuation of three volatile organic compounds, toluene, carbon tetrachloride, and tetrachloroethene (?1–10 mg L?1) was performed in a 3 m deep, sandy aquifer isolated within a 24 m long, 2 m wide, three...

  4. Linear Dynamics of Double-Porosity Dual-Permeability Materials I. Governing Equations and Acoustic Attenuation

    E-Print Network [OSTI]

    high-pressure regions to the relatively sti#11; low- pressure regions. Such mesoscopic ow attenuates #21; 1 mm). Seismic wavelengths used for oil and gas exploration purposes are typically in the range in their uid pressures. An internal equilibra- tion then takes place with uid owing from the more compliant

  5. Diffuse attenuation coefficient of downwelling irradiance: An evaluation of remote sensing methods

    E-Print Network [OSTI]

    Lee, Zhongping

    Diffuse attenuation coefficient of downwelling irradiance: An evaluation of remote sensing methods February 2005. [1] The propagation of downwelling irradiance at wavelength l from surface to a depth (z in situ measurements of the vertical profiles of downwelling irradiance. The comparisons show that the two

  6. Reaching Out to See: Arm Position Can Attenuate Human Visual Loss

    E-Print Network [OSTI]

    Robertson, Lynn

    Reaching Out to See: Arm Position Can Attenuate Human Visual Loss Krista Schendel and Lynn C on or near the hands, arms, and face. These cells have now been found in frontal, parietal, and subcortical processing of visual stimuli placed near the hands and arms, we hypothesized that arm position may be capable

  7. POLICY FOR VALIDATING ATTENUATED STRAINS OF BL31 Adopted by COMS on 26 May 2006

    E-Print Network [OSTI]

    Paulsson, Johan

    must take place at BL3 unless lesser containment is approved by COMS. i. Harvard has no BL4 and aliquoted in quantities sufficient for use until the project is completed. This will be the seed stock strains remain attenuated over long periods. a. Vials of Seed Stock and Working Stock derived from Seed

  8. Attenuation and speed of ultrasoundin lung BioacousticResearchLaboratory,Universityof Illinois,Urbana,Illinois61801

    E-Print Network [OSTI]

    Illinois at Urbana-Champaign, University of

    Attenuation and speed of ultrasoundin lung F. Dunn Bioacoustic in freshly excised dog lung at 1 MHz was un- usuallyhigh,viz., morethananorderofmagnitude greater than air excised lung was ligated at the bronchial tube to retain such residual air that the density of the speci

  9. A replication-deficient rabies virus vaccine expressing Ebola virus glycoprotein is highly attenuated for neurovirulence

    SciTech Connect (OSTI)

    Papaneri, Amy B.; Wirblich, Christoph; Cann, Jennifer A.; Cooper, Kurt; Jahrling, Peter B.; Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick MD, 21702 ; Schnell, Matthias J.; Blaney, Joseph E.

    2012-12-05

    We are developing inactivated and live-attenuated rabies virus (RABV) vaccines expressing Ebola virus (EBOV) glycoprotein for use in humans and endangered wildlife, respectively. Here, we further characterize the pathogenesis of the live-attenuated RABV/EBOV vaccine candidates in mice in an effort to define their growth properties and potential for safety. RABV vaccines expressing GP (RV-GP) or a replication-deficient derivative with a deletion of the RABV G gene (RV{Delta}G-GP) are both avirulent after intracerebral inoculation of adult mice. Furthermore, RV{Delta}G-GP is completely avirulent upon intracerebral inoculation of suckling mice unlike parental RABV vaccine or RV-GP. Analysis of RV{Delta}G-GP in the brain by quantitative PCR, determination of virus titer, and immunohistochemistry indicated greatly restricted virus replication. In summary, our findings indicate that RV-GP retains the attenuation phenotype of the live-attenuated RABV vaccine, and RV{Delta}G-GP would appear to be an even safer alternative for use in wildlife or consideration for human use.

  10. Site Screening and Technical Guidance for Monitored Natural Attenuation at DOE Sites

    SciTech Connect (OSTI)

    Borns, D.J.; Brady, P.V.; Brady, W.D.; Krupka, K.M.; Spalding, B.P.; Waters, R.D.; Zhang, P.

    1999-03-01

    Site Screening and Technical Guidance for Monitored Natural Attenuation at DOE Sites briefly outlines the biological and geochemical origins of natural attenuation, the tendency for natural processes in soils to mitigate contaminant transport and availability, and the means for relying on monitored natural attenuation (MNA) for remediation of contaminated soils and groundwaters. This report contains a step-by-step guide for (1) screening contaminated soils and groundwaters on the basis of their potential for remediation by natural attenuation and (2) implementing MNA consistent with EPA OSWER Directive 9200.4-17. The screening and implementation procedures are set up as a web-based tool (http://www.sandia.gov/eesector/gs/gc/na/mnahome.html) to assist US Department of Energy (DOE) site environmental managers and their staff and contractors to adhere to EPA guidelines for implementing MNA. This document is intended to support the Decision Maker's Framework Guide and Monitoring Guide both to be issued from DOE EM-40. Further technical advances may cause some of the approach outlined in this document to change over time.

  11. Figure 5 : Inversed attenuation tomography The Fresnel volume thus defined, also called Frchet kernel

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Figure 5 : Inversed attenuation tomography The Fresnel volume thus defined, also called Fréchet system with the LSQR algorithm : Because the size of the Fresnel volume thus defined is dependent propose to compute the Fresnel weights for a monochromatic wave, increasing its frequency at each step

  12. Measurement and implications of frequency dependence of attenuation Ved Leki a,

    E-Print Network [OSTI]

    dependence of attenuation q can be represented by a power law qq0­ . Despite its importance, efforts law, q­ , with a model-dependent , usually thought to be smaller than 0.5 (e.g. Anderson and Minster developed (Selby and Woodhouse, 2002; Gung and Romanowicz, 2004; Dalton and Ekström, 2006), offering

  13. Study of the seismic attenuation generated by the mud layer in Lake Maracaibo, Venezuela 

    E-Print Network [OSTI]

    Perez Arredondo, Javier Antonio

    2004-09-30

    by the gassy sediment in the mud layer, and the high attenuation of the compressional and shear waves. This mud layer sediment is heavy and is not suspended in the water. Furthermore, it is compacted enough to support shear stresses and, therefore, has a...

  14. Gamma-ray Albedo of Small Solar System Bodies

    SciTech Connect (OSTI)

    Moskalenko, I.V.

    2008-03-25

    We calculate the {gamma}-ray albedo flux from cosmic-ray (CR) interactions with the solid rock and ice in Main Belt asteroids and Kuiper Belt objects (KBOs) using the Moon as a template. We show that the {gamma}-ray albedo for the Main Belt and KBOs strongly depends on the small-body mass spectrum of each system and may be detectable by the forthcoming Gamma Ray Large Area Space Telescope (GLAST). If detected, it can be used to derive the mass spectrum of small bodies in the Main Belt and Kuiper Belt and to probe the spectrum of CR nuclei at close-to-interstellar conditions. The orbits of the Main Belt asteroids and KBOs are distributed near the ecliptic, which passes through the Galactic center and high Galactic latitudes. Therefore, the {gamma}-ray emission by the Main Belt and Kuiper Belt has to be taken into account when analyzing weak {gamma}-ray sources close to the ecliptic. The asteroid albedo spectrum also exhibits a 511 keV line due to secondary positrons annihilating in the rock. This may be an important and previously unrecognized celestial foreground for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the Galactic 511 keV line emission including the direction of the Galactic center. For details of our calculations and references see [1].

  15. Gas Chromatography -Mass Spectrometry

    E-Print Network [OSTI]

    Nizkorodov, Sergey

    GCMS - 1 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS OF ETHANOL AND BENZENE IN GASOLINE Last updated: June 17, 2014 #12;GCMS - 2 Gas Chromatography - Mass Spectrometry GC-MS ANALYSIS). The goal of this experiment is to separate the components in a sample of gasoline using Gas Chromatography

  16. The Origins of Mass

    SciTech Connect (OSTI)

    Lincoln, Don

    2014-07-30

    The Higgs boson was discovered in July of 2012 and is generally understood to be the origin of mass. While those statements are true, they are incomplete. It turns out that the Higgs boson is responsible for only about 2% of the mass of ordinary matter. In this dramatic new video, Dr. Don Lincoln of Fermilab tells us the rest of the story.

  17. Elbow mass flow meter

    DOE Patents [OSTI]

    McFarland, A.R.; Rodgers, J.C.; Ortiz, C.A.; Nelson, D.C.

    1994-08-16

    The present invention includes a combination of an elbow pressure drop generator and a shunt-type mass flow sensor for providing an output which gives the mass flow rate of a gas that is nearly independent of the density of the gas. For air, the output is also approximately independent of humidity. 3 figs.

  18. Seismic mass Top electrode

    E-Print Network [OSTI]

    Kraft, Michael

    assembly process. For the measurements of the physical dimensions of the seismic mass a micrometer was usedSeismic mass Top electrode Bottom electrode x C1 C2 Chapter 4: The Micromachined Sensing Element supplied by Druck, Ltd., Groby, Leics. The manufacturing process at Druck was still in its experimental

  19. The Origins of Mass

    ScienceCinema (OSTI)

    Lincoln, Don

    2014-08-07

    The Higgs boson was discovered in July of 2012 and is generally understood to be the origin of mass. While those statements are true, they are incomplete. It turns out that the Higgs boson is responsible for only about 2% of the mass of ordinary matter. In this dramatic new video, Dr. Don Lincoln of Fermilab tells us the rest of the story.

  20. X-ray laser

    DOE Patents [OSTI]

    Nilsen, Joseph (Livermore, CA)

    1991-01-01

    An X-ray laser (10) that lases between the K edges of carbon and oxygen, i.e. between 44 and 23 Angstroms, is provided. The laser comprises a silicon (12) and dysprosium (14) foil combination (16) that is driven by two beams (18, 20) of intense line focused (22, 24) optical laser radiation. Ground state nickel-like dysprosium ions (34) are resonantly photo-pumped to their upper X-ray laser state by line emission from hydrogen-like silicon ions (32). The novel X-ray laser should prove especially useful for the microscopy of biological specimens.

  1. Exotic massive hadrons and ultra-high energy cosmic rays

    E-Print Network [OSTI]

    Ivone F. M. Albuquerque; Glennys R. Farrar; Edward W. Kolb

    1998-10-02

    We investigate the proposal that primary cosmic rays of energy above the Greisen-Zatsepin-Kuzmin cutoff are exotic massive strongly interacting particles (uhecrons). We study the properties of air showers produced by uhecrons and find that masses in excess of about 50 GeV are inconsistent with the highest energy event observed. We also estimate that with sufficient statistics a uhecron of mass as low as 10 GeV may be distinguished from a proton.

  2. Dark Matter and Cosmic Rays from Light Gauginos

    E-Print Network [OSTI]

    Glennys R. Farrar

    1997-04-13

    An attractive class of SUSY-breaking mechanisms predicts a photino mass of order 1 GeV. Relic photinos can naturally account for the observed dark matter. Detection of these light photinos is discussed and contrasted with conventional WIMPs. In this scenario the gluino mass is about 100 MeV. The lightest gluino-containing baryon could account for the recently observed ultra-high energy cosmic rays, which violate the GZK bound.

  3. X-ray emitting young stars in the Orion Nebula

    E-Print Network [OSTI]

    Eric D. Feigelson; Patrick Broos; James A. Gaffney III; Gordon Garmire; Lynne A. Hillenbrand; Steven H. Pravdo; Leisa Townsley; Yohko Tsuboi

    2002-03-19

    The Orion Nebula Cluster and the molecular cloud in its vicinity have been observed with the ACIS-I detector on board the Chandra X-ray Observatory with 23 hours exposure. We detect 1075 X-ray sources: 91% are spatially associated with known stellar members of the cluster, and 7% are newly identified deeply embedded cloud members. This provides the largest X-ray study of a pre-main sequence stellar population. We examine here the X-ray properties of Orion young stars as a function of mass. Results include: (a) the discovery of rapid variability in the O9.5 31 M_o star \\theta^2A Ori, and several early B stars, inconsistent with the standard model of X-ray production in small wind shocks; (b) support for the hypothesis that intermediate-mass mid-B through A type stars do not themselves produce significant X-ray emission; (c) confirmation that low-mass G- through M-type T Tauri stars exhibit powerful flaring but typically at luminosities considerably below the `saturation' level; (d) confirmation that the presence or absence of a circumstellar disk has no discernable effect on X-ray emission; (e) evidence that T Tauri plasma temperatures are often very high with T >= 100 MK, even when luminosities are modest and flaring is not evident; and (f) detection of the largest sample of pre-main sequence very low mass objects showing high flaring levels and a decline in magnetic activity as they evolve into L- and T-type brown dwarfs.

  4. Compton scattering for spectroscopic detection of ultra-fast, high flux, broad energy range X-rays

    SciTech Connect (OSTI)

    Cipiccia, S.; Wiggins, S. M.; Brunetti, E.; Vieux, G.; Yang, X.; Welsh, G. H.; Anania, M.; Islam, M. R.; Ersfeld, B.; Jaroszynski, D. A. [Scottish Universities Physics Alliance, Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG (United Kingdom)] [Scottish Universities Physics Alliance, Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG (United Kingdom); Maneuski, D.; Montgomery, R.; Smith, G.; Hoek, M.; Hamilton, D. J.; Shea, V. O. [Scottish Universities Physics Alliance, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom)] [Scottish Universities Physics Alliance, School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Issac, R. C. [Scottish Universities Physics Alliance, Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG (United Kingdom) [Scottish Universities Physics Alliance, Department of Physics, University of Strathclyde, John Anderson Building, 107 Rottenrow, Glasgow G4 0NG (United Kingdom); Research Department of Physics, Mar Athanasius College, Kothamangalam 686666, Kerala (India); Lemos, N. R. C.; Dias, J. M. [GoLP/Instituto de Plasmas eFusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisbon (Portugal)] [GoLP/Instituto de Plasmas eFusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Avenida Rovisco Pais, 1049-001 Lisbon (Portugal); Symes, D. R. [Central Laser Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, OX11 0QX Didcot (United Kingdom)] [Central Laser Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, OX11 0QX Didcot (United Kingdom); and others

    2013-11-15

    Compton side-scattering has been used to simultaneously downshift the energy of keV to MeV energy range photons while attenuating their flux to enable single-shot, spectrally resolved, measurements of high flux X-ray sources to be undertaken. To demonstrate the technique a 1 mm thick pixelated cadmium telluride detector has been used to measure spectra of Compton side-scattered radiation from a Cobalt-60 laboratory source and a high flux, high peak brilliance X-ray source of betatron radiation from a laser-plasma wakefield accelerator.

  5. Absolute neutrino mass measurements

    SciTech Connect (OSTI)

    Wolf, Joachim [Karlsruhe Institute of Technology (KIT), IEKP, Postfach 3640, 76021 Karlsruhe (Germany)

    2011-10-06

    The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2{beta}) searches, single {beta}-decay experiments provide a direct, model-independent way to determine the absolute neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy.Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments in Mainz and Troitsk, using tritium as beta emitter. The next generation tritium {beta}-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope ({sup 137}Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R and D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2{beta} decay and single {beta}-decay.

  6. Development of a model of an x-ray tube transmission source

    SciTech Connect (OSTI)

    Goda, Joetta M; Ianakiev, Kiril D; Moss, Cal E

    2009-01-01

    In support of the development of an x-ray tube based source for transmission measurements of UF6 gas, we have developed a one-dimensional, spreadsheet-based model of the source. Starting with the spectrum produced by an x-ray tube we apply the linear attenuation coefficients for various notch filters, the aluminum pipe, and UF6 gas. This model allows calculation of the transmitted spectrum based on the type of filter, the thickness of the filter, the x-ray tube high voltage, the Al pipe thickness, and the UF6 gas pressure. The sensitivity of the magnitude of the transmission peak produced by the notch filter to any of these variables can be explored quickly and easily to narrow the choices for experimental measurements. To validate the spreadsheet based model, comparisons have been made to various experimental data.

  7. Supply and demand in the material recovery system for cathode ray tube glass

    E-Print Network [OSTI]

    Nadeau, Marie-Claude

    This paper presents an analysis of the material recovery system for leaded glass from cathode ray tubes (CRTs). In particular, the global mass flow of primary and secondary CRT glass and the theoretical capacities for using ...

  8. Gamma Ray Pulsars: Observations

    E-Print Network [OSTI]

    David J. Thompson

    2001-01-03

    High-energy gamma rays are a valuable tool for studying particle acceleration and radiation in the magnetospheres of energetic pulsars. The six or more pulsars seen by CGRO/EGRET show that: the light curves usually have double-peak structures (suggesting a broad cone of emission); gamma rays are frequently the dominant component of the radiated power; and all the spectra show evidence of a high-energy turnover. Unless a new pulsed component appears at higher energies, progress in gamma-ray pulsar studies will be greatest in the 1-20 GeV range. Ground-based telescopes whose energy ranges extend downward toward 10 GeV should make important measurements of the spectral cutoffs. The Gamma-ray Large Area Space Telescope (GLAST), now in planning for a launch in 2005, will provide a major advance in sensitivity, energy range, and sky coverage.

  9. Mass of Ca-36 

    E-Print Network [OSTI]

    Tribble, Robert E.; Cossairt, J. D.; Kenefick, R. A.

    1977-01-01

    VIK W C VO I. UMK 15, 5 UMBER 6 Mass of ~Cat R. E. Tribble, ~ J. D. Cossairt, and R. A. Kenefick Cyclotron Institute and Physics Department, Texas AChM University, College Station, Texas 77843 (Received 14 October 1976) The ' Ca('He, He)' Ca... reaction has been used to provide the first observation of the nuclide ' Ca. The Q value and mass excess were found to be ?57.58~0.04 and ?6.44+0.04 MeV, respectively. The new mass completes four members of the A = 36 isobaric quintet and hence serves...

  10. Gamma-Ray Bursts

    E-Print Network [OSTI]

    P. Meszaros

    2006-05-30

    Gamma-ray bursts are the most luminous explosions in the Universe, and their origin and mechanism are the focus of intense research and debate. More than three decades after their discovery, and after pioneering breakthroughs from space and ground experiments, their study is entering a new phase with the recently launched Swift satellite. The interplay between these observations and theoretical models of the prompt gamma ray burst and its afterglow is reviewed.

  11. Masses of Stellar Black Holes and Testing Theories of Gravitation

    E-Print Network [OSTI]

    K. A. Postnov; A. M. Cherepashchuk

    2004-01-22

    We analyze the mass distribution of stellar black holes derived from the light and radial velocity curves of optical stars in close binary systems using dynamical methods. The systematic errors inherent in this approach are discussed. These are associated primarily with uncertainties in models for the contribution from gaseous structures to the optical brightness of the systems under consideration. The mass distribution is nearly flat in the range 4-15M_sun. This is compared with the mass distribution for black holes in massive close binaries, which can be manifest as ultraluminous X-ray sources (L_x > 10^39 erg/s) observed in other galaxies. If the X-ray luminosities of these objects correspond to the Eddington limit, the black-hole mass distribution should be described by a power law, which is incompatible with the flat shape derived dynamically from observations of close binaries in our Galaxy. One possible explanation of this discrepancy is the rapid evaporation of stellar-mass black holes predicted in recent multi-dimensional models of gravity. This hypothesis can be verifed by measuring the stellar black-hole mass spectrum or finding isolated or binary black holes with masses below 3M_sun.

  12. Gamma ray camera

    DOE Patents [OSTI]

    Perez-Mendez, Victor (Berkeley, CA)

    1997-01-01

    A gamma ray camera for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array.

  13. Gamma ray camera

    DOE Patents [OSTI]

    Perez-Mendez, V.

    1997-01-21

    A gamma ray camera is disclosed for detecting rays emanating from a radiation source such as an isotope. The gamma ray camera includes a sensor array formed of a visible light crystal for converting incident gamma rays to a plurality of corresponding visible light photons, and a photosensor array responsive to the visible light photons in order to form an electronic image of the radiation therefrom. The photosensor array is adapted to record an integrated amount of charge proportional to the incident gamma rays closest to it, and includes a transparent metallic layer, photodiode consisting of a p-i-n structure formed on one side of the transparent metallic layer, and comprising an upper p-type layer, an intermediate layer and a lower n-type layer. In the preferred mode, the scintillator crystal is composed essentially of a cesium iodide (CsI) crystal preferably doped with a predetermined amount impurity, and the p-type upper intermediate layers and said n-type layer are essentially composed of hydrogenated amorphous silicon (a-Si:H). The gamma ray camera further includes a collimator interposed between the radiation source and the sensor array, and a readout circuit formed on one side of the photosensor array. 6 figs.

  14. Heavy Hybrid mesons Masses

    E-Print Network [OSTI]

    F. Iddir; L. Semlala

    2006-11-25

    We estimate the ground state masses of the heavy hybrid mesons using a phenomenological QCD-type potential. 0^{- -},1^{- -},0^{- +},1^{- +} and 0^{+ -} J^{PC} states are considered.

  15. Mass of astrophysically relevant $^{31}$Cl and the breakdown of the isobaric multiplet mass equation

    E-Print Network [OSTI]

    Kankainen, A; Eronen, T; Hakala, J; Jokinen, A; Koponen, J; Moore, I D; Nesterenko, D; Reinikainen, J; Rinta-Antila, S; Voss, A; Äystö, J

    2015-01-01

    The mass of $^{31}$Cl has been measured with the JYFLTRAP double Penning trap mass spectrometer at the Ion-Guide Isotope Separator On-Line (IGISOL) facility. The determined mass-excess value, -7034.7(34) keV, is 15 times more precise than in the Atomic Mass Evaluation 2012. The quadratic form of the isobaric multiplet mass equation for the T=3/2 quartet at A=31 fails ($\\chi^2_n$=11.6) and a non-zero cubic term, d=-3.49(44) keV, is obtained when the new mass value is adopted. $^{31}$Cl has been found to be less proton-bound with a proton separation energy of $S_p$=265(4) keV. Energies for the excited states in $^{31}$Cl and the photodisintegration rate on $^{31}$Cl have been determined with significantly improved precision using the new $S_p$ value. The improved photodisintegration rate helps to constrain astrophysical conditions where $^{30}$S can act as a waiting point in the rapid proton capture process in type I x-ray bursts.

  16. Mass of astrophysically relevant $^{31}$Cl and the breakdown of the isobaric multiplet mass equation

    E-Print Network [OSTI]

    A. Kankainen; L. Canete; T. Eronen; J. Hakala; A. Jokinen; J. Koponen; I. D. Moore; D. Nesterenko; J. Reinikainen; S. Rinta-Antila; A. Voss; J. Äystö

    2015-11-25

    The mass of $^{31}$Cl has been measured with the JYFLTRAP double Penning trap mass spectrometer at the Ion-Guide Isotope Separator On-Line (IGISOL) facility. The determined mass-excess value, -7034.7(34) keV, is 15 times more precise than in the Atomic Mass Evaluation 2012. The quadratic form of the isobaric multiplet mass equation for the T=3/2 quartet at A=31 fails ($\\chi^2_n$=11.6) and a non-zero cubic term, d=-3.49(44) keV, is obtained when the new mass value is adopted. $^{31}$Cl has been found to be less proton-bound with a proton separation energy of $S_p$=265(4) keV. Energies for the excited states in $^{31}$Cl and the photodisintegration rate on $^{31}$Cl have been determined with significantly improved precision using the new $S_p$ value. The improved photodisintegration rate helps to constrain astrophysical conditions where $^{30}$S can act as a waiting point in the rapid proton capture process in type I x-ray bursts.

  17. Solids mass flow determination

    DOE Patents [OSTI]

    Macko, Joseph E. (Hempfield Township, Westmoreland County, PA)

    1981-01-01

    Method and apparatus for determining the mass flow rate of solids mixed with a transport fluid to form a flowing mixture. A temperature differential is established between the solids and fluid. The temperature of the transport fluid prior to mixing, the temperature of the solids prior to mixing, and the equilibrium temperature of the mixture are monitored and correlated in a heat balance with the heat capacities of the solids and fluid to determine the solids mass flow rate.

  18. Volume Ray Casting Neslisah Torosdagli

    E-Print Network [OSTI]

    Pattanaik, Sumanta N.

    Volume Ray Casting Neslisah Torosdagli #12;Overview · Light Transfer Optical Models · Math behind Direct Volume Ray Casting · Demonstration · Transfer Functions · Details of our Application · References #12;What is Volume Ray Casting? · Volume Ray Casting is construction of 3D volume using stack of 2D

  19. An alternative interpretation for cosmic ray peaks

    E-Print Network [OSTI]

    Kim, Doojin

    2015-01-01

    We propose an alternative mechanism based upon dark matter (DM) interpretation for anomalous peak signatures in cosmic ray measurements, assuming an extended dark sector with two DM species. This is contrasted with previous effort to explain various line-like cosmic-ray excesses in the context of DM models where the relevant DM candidate directly annihilates into Standard Model (SM) particles. The heavier DM is assumed to annihilate to an on-shell intermediate state. As the simplest choice, it decays directly into the lighter DM along with an unstable particle which in turn decays to a pair of SM states corresponding to the interesting cosmic anomaly. We show that a sharp continuum energy peak can be readily generated under the proposed DM scenario, depending on dark sector particle mass spectra. Remarkably, such a peak is robustly identified as half the mass of the unstable particle. Furthermore, other underlying mass parameters are analytically related to the shape of energy spectrum. We apply this idea to ...

  20. Dynamic effective mass of granular media

    E-Print Network [OSTI]

    John Valenza; Chaur-Jian Hsu; Rohit Ingale; Nicolas Gland; Hernán A. Makse; David Linton Johnson

    2009-05-08

    We report an experimental and theoretical investigation of the frequency-dependent effective mass, $\\tilde{M}(\\omega)$, of loose granular particles which occupy a rigid cavity to a given filling fraction, the remaining volume being air of differing humidities. This allow us to study the mechanisms of elastic response and attenuation of acoustic modes in granular media. We demonstrate that this is a sensitive and direct way to measure those properties of the granular medium that are the cause of the changes in acoustic properties of structures containing grain-filled cavities. Specifically, we apply this understanding to the case of the flexural resonances of a rectangular bar with a grain-filled cavity within it. The dominant features of $\\tilde{M}(\\omega)$ are a sharp resonance and a broad background, which we analyze within the context of simple models. We find that: a) These systems may be understood in terms of a height-dependent and diameter-dependent effective sound speed ($\\sim 100-300$ m/s) and an effective viscosity ($\\sim 5\\times 10^4$ Poise). b) There is a dynamic Janssen effect in the sense that, at any frequency, and depending on the method of sample preparation, approximately one-half of the effective mass is borne by the side walls of the cavity and one-half by the bottom. c) By performing experiments under varying humidity conditions we conclude that, on a fundamental level, damping of acoustic modes is dominated by adsorbed films of water at grain-grain contacts in our experiments, not by global viscous dampening. d) There is a monotonically increasing effect of humidity on the dampening of the fundamental resonance within the granular medium which translates to a non-monotonic, but predictable, variation of dampening within the grain-loaded bar.

  1. Eta Car and Its Surroundings: the X-ray Diagnosis

    E-Print Network [OSTI]

    M. F. Corcoran; K. Hamaguchi

    2007-03-02

    X-ray emission from the supermassive star Eta Carinae (\\ec) originates from hot shocked gas produced by current stellar mass loss as well as ejecta from prior eruptive events. Absorption of this emission by cool material allows the determination of the spatial and temporal distribution of this material. Emission from the shocked gas can provide important information about abundances through the study of thermal X-ray line emission. We discuss how studies of the X-ray emission from Eta Car at a variety of temporal, spatial and spectral scales and resolutions have helped refine our knowledge of both the continuous and discrete mass loss from the system, and its interactions with more extended material around the star.

  2. Technological cost-reduction pathways for attenuator wave energy converters in the marine hydrokinetic environment.

    SciTech Connect (OSTI)

    Bull, Diana L; Ochs, Margaret Ellen

    2013-09-01

    This report considers and prioritizes the primary potential technical costreduction pathways for offshore wave activated body attenuators designed for ocean resources. This report focuses on technical research and development costreduction pathways related to the device technology rather than environmental monitoring or permitting opportunities. Three sources of information were used to understand current cost drivers and develop a prioritized list of potential costreduction pathways: a literature review of technical work related to attenuators, a reference device compiled from literature sources, and a webinar with each of three industry device developers. Data from these information sources were aggregated and prioritized with respect to the potential impact on the lifetime levelized cost of energy, the potential for progress, the potential for success, and the confidence in success. Results indicate the five most promising costreduction pathways include advanced controls, an optimized structural design, improved power conversion, planned maintenance scheduling, and an optimized device profile.

  3. Evaluation of Natural Attenuation as One Component of Chloroethene-Contaminated Groundwater Remediation

    SciTech Connect (OSTI)

    K.S. Sorenson; L.N. Peterson; T.S. Green

    1998-10-01

    Test Area North (TAN) at the Idaho National Engineering and Environmental Laboratory (INEEL) is the site of a large trichloroethene (TCE) plume resulting from the historical injection of wastewater into the Snake River Plain Aquifer. The TAN Record of Decision (ROD) selected pump and treat as the final remedy and included a contingency for post-ROD treatability studies of alternative technologies. The technologies still under consideration are in-situ bioremediation, in-situ chemical oxidation, and natural attenuation. Both anaerobic and aerobic laboratory microcosm studies indicate the presence of microorganisms capable of chloroethene degradation. Field data indicate that TCE concentrations decrease relative to tritium and tetrachloroethene indicating an as yet unknown process is contributing to natural attenuation of TCE. Several methods for analyzing the field data have been evaluated and important limitations identified. Early results from the continued evaluation of the three alternative technologies suggest the combined approach of active remediation of the source area (in situ bioremediation and/or chemical oxidation replacing or augmenting pump and treat) and natural attenuation within the dissolved phase plume may be more cost and schedule effective than the base case pump and treat.

  4. Evaluation of Natural Attenuation as One Component of Chloroethene-Contaminated Groundwater Remediation

    SciTech Connect (OSTI)

    Sorenson, K.S.; Peterson, L.N.; Green, T.S.

    1998-10-01

    Test Area North (TAN) at the Idaho National Engineering and Environmental Laboratory (INEEL) is the site of a large trichloroethene (TCE) plume resulting from the historical injection of wastewater into the Snake River Plain Aquifer. The TAN Record of Decision (ROD) selected pump and treat as the final remedy and included a contingency for post-ROD treatability studies of alternative technologies. The technologies still under consideration are in situ bioremediation, in situ chemical oxidation, and natural attenuation. Both anaerobic and aerobic laboratory microcosm studies indicate the presence of microorganisms capable of chloroethene degradation. Field data indicate that TCE concentrations decrease relative to tritium and tetrachloroethene indicating an as yet unknown process is contributing to natural attenuation of TCE. Several methods for analyzing the field data have been evaluated and important limitations identified. Early results from the continued evaluation of the three alternative technologies suggest the combined approach of active remediation of the source area (in situ bioremediation and/or chemical oxidation replacing or augmenting pump and treat) and natural attenuation within the dissolved phase plume may be more cost and schedule effective than the base case pump and treat.

  5. Activation of farnesoid X receptor attenuates hepatic injury in a murine model of alcoholic liver disease

    SciTech Connect (OSTI)

    Wu, Weibin; Institutes of Biomedical Science, Fudan University, Shanghai 200032 ; Zhu, Bo; Peng, Xiaomin; Zhou, Meiling; Jia, Dongwei; Gu, Jianxin; Institutes of Biomedical Science, Fudan University, Shanghai 200032

    2014-01-03

    Highlights: •FXR activity was impaired by chronic ethanol ingestion in a murine model of ALD. •Activation of FXR attenuated alcohol-induced liver injury and steatosis. •Activation of FXR attenuated cholestasis and oxidative stress in mouse liver. -- Abstract: Alcoholic liver disease (ALD) is a common cause of advanced liver disease, and considered as a major risk factor of morbidity and mortality worldwide. Hepatic cholestasis is a pathophysiological feature observed in all stages of ALD. The farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily, and plays an essential role in the regulation of bile acid, lipid and glucose homeostasis. However, the role of FXR in the pathogenesis and progression of ALD remains largely unknown. Mice were fed Lieber-DeCarli ethanol diet or an isocaloric control diet. We used a specific agonist of FXR WAY-362450 to study the effect of pharmacological activation of FXR in alcoholic liver disease. In this study, we demonstrated that FXR activity was impaired by chronic ethanol ingestion in a murine model of ALD. Activation of FXR by specific agonist WAY-362450 protected mice from the development of ALD. We also found that WAY-362450 treatment rescued FXR activity, suppressed ethanol-induced Cyp2e1 up-regulation and attenuated oxidative stress in liver. Our results highlight a key role of FXR in the modulation of ALD development, and propose specific FXR agonists for the treatment of ALD patients.

  6. Improvements to Regional Explosion Identification using Attenuation Models of the Lithosphere

    SciTech Connect (OSTI)

    Pasyanos, M E; Walter, W R

    2009-03-30

    Regional P/S amplitudes have been recognized as an effective discriminant between earthquakes and explosions. While closely spaced earthquake and explosions generally discriminate easily, the application of this technique to broad regions has been hampered by large variations in the amplitude of regional phases due to the attenuation structure of the crust and upper mantle. Making use of a recent P-wave and S-wave attenuation model of the lithosphere, we have found that correcting the events using our amplitude methodology significantly reduces the scattering in the earthquake population. We demonstrate an application of this technique to station NIL (Nilore, Pakistan) using broad area earthquakes and the 1998 Indian nuclear explosion recorded at the station using the Pn/Lg discriminant in the 1-2 Hz passband. We find that the explosion, which is lost in the scatter of the earthquakes in the uncorrected discriminant, clearly separates by correcting for the attenuation structure. We see a similar reduction in scatter and separation for the Pn/Sn and Pg/Lg discriminants in the same passband.

  7. X-RAY EMISSION FROM MAGNETIC MASSIVE STARS

    SciTech Connect (OSTI)

    Nazé, Yaël; Petit, Véronique; Rinbrand, Melanie; Owocki, Stan; Cohen, David; Ud-Doula, Asif; Wade, Gregg A.

    2014-11-01

    Magnetically confined winds of early-type stars are expected to be sources of bright and hard X-rays. To clarify the systematics of the observed X-ray properties, we have analyzed a large series of Chandra and XMM-Newton observations, corresponding to all available exposures of known massive magnetic stars (over 100 exposures covering ?60% of stars compiled in the catalog of Petit et al.). We show that the X-ray luminosity is strongly correlated with the stellar wind mass-loss rate, with a power-law form that is slightly steeper than linear for the majority of the less luminous, lower- M-dot B stars and flattens for the more luminous, higher- M-dot O stars. As the winds are radiatively driven, these scalings can be equivalently written as relations with the bolometric luminosity. The observed X-ray luminosities, and their trend with mass-loss rates, are well reproduced by new MHD models, although a few overluminous stars (mostly rapidly rotating objects) exist. No relation is found between other X-ray properties (plasma temperature, absorption) and stellar or magnetic parameters, contrary to expectations (e.g., higher temperature for stronger mass-loss rate). This suggests that the main driver for the plasma properties is different from the main determinant of the X-ray luminosity. Finally, variations of the X-ray hardnesses and luminosities, in phase with the stellar rotation period, are detected for some objects and they suggest that some temperature stratification exists in massive stars' magnetospheres.

  8. Cosmic ray recipes

    E-Print Network [OSTI]

    Franco Ferrari; Ewa Szuszkiewicz

    2006-01-08

    Cosmic rays represent one of the most fascinating research themes in modern astronomy and physics. After almost a century since their discovery, a huge amount of scientific literature has been written on this topic and it is not always easy to extract from it the necessary information for somebody who approaches the subject for the first time. This has been the main motivation for preparing this article, which is a concise and self-contained review for whoever is interested in studying cosmic rays. The priority has been given here to well established facts, which are not at risk to get obsolete in a few years due to the fast progress of the research in this field. Also many data are presented, which are useful to characterize the doses of ionizing radiation delivered to organisms living on the Earth due to cosmic rays. The technical terms which are often encountered in the scientific literature are explained in a separate appendix.

  9. Can Naked Singularities Yield Gamma Ray Bursts?

    E-Print Network [OSTI]

    H. M. Antia

    1998-07-09

    Gamma-ray bursts are believed to be the most luminous objects in the Universe. There has been some suggestion that these arise from quantum processes around naked singularities. The main problem with this suggestion is that all known examples of naked singularities are massless and hence there is effectively no source of energy. It is argued that a globally naked singularity coupled with quantum processes operating within a distance of the order of Planck length of the singularity will probably yield energy burst of the order of M_pc^2\\approx2\\times 10^{16} ergs, where M_p is the Planck mass.

  10. Ray Smith | Y-12 National Security Complex

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100 Winners * Impacts on GlobalRachel2RateCaseElements Sign In About | FYRayRay

  11. Photon: history, mass, charge

    E-Print Network [OSTI]

    L. B. Okun

    2006-02-13

    The talk consists of three parts. ``History'' briefly describes the emergence and evolution of the concept of photon during the first two decades of the 20th century. ``Mass'' gives a short review of the literature on the upper limit of the photon's mass. ``Charge'' is a critical discussion of the existing interpretation of searches for photon charge. Schemes, in which all photons are charged, are grossly inconsistent. A model with three kinds of photons (positive, negative and neutral) seems at first sight to be more consistent, but turns out to have its own serious problems.

  12. X-ray microtomography

    SciTech Connect (OSTI)

    Landis, Eric N.; Keane, Denis T.

    2010-12-15

    In this tutorial, we describe X-ray microtomography as a technique to nondestructively characterize material microstructure in three dimensions at a micron level spatial resolution. While commercially available laboratory scale instrumentation is available, we focus our attention on synchrotron-based systems, where we can exploit a high flux, monochromatic X-ray beam to produce high fidelity three-dimensional images. A brief description of the physics and the mathematical analysis behind the technique is followed by example applications to specific materials characterization problems, with a particular focus on the utilization of three-dimensional image processing that can be used to extract a wide range of useful information.

  13. X-ray and Near-infrared Studies of a Star-forming Cloud; L1448

    E-Print Network [OSTI]

    Tsujimoto, M; Tsuboi, Y

    2005-01-01

    We present the results of X-ray and near-infrared (NIR) observations of L1448, a star-forming region in the Perseus cloud complex using the Chandra X-ray Observatory and the 4 m telescope at the Kitt Peak National Observatory. We detect 72 X-ray sources in a ~17 arcmin x 17 arcmin region with a ~68 ks ACIS exposure, for which we conduct follow-up NIR imaging observations in a concentric ~11 arcmin x 11 arcmin region with FLAMINGOS down to m_Ks ~ 17 mag. Twelve X-ray sources have NIR or optical counterparts. By plotting X-ray mean energy versus NIR to X-ray flux ratio, the X-ray sources are clearly separated into two groups. The X-ray spectral and temporal features as well as NIR magnitudes and colors indicate that one group mainly consists of young stellar objects (YSOs) in the cloud and the other of background extragalactic sources. Ten X-ray-emitting YSO candidates are thus newly identified, which are low-mass or brown dwarf mass sources from their NIR magnitudes. In addition, a possible X-ray signal is fou...

  14. X-ray and Near-infrared Studies of a Star-forming Cloud; L1448

    E-Print Network [OSTI]

    M. Tsujimoto; N. Kobayashi; Y. Tsuboi

    2005-06-27

    We present the results of X-ray and near-infrared (NIR) observations of L1448, a star-forming region in the Perseus cloud complex using the Chandra X-ray Observatory and the 4 m telescope at the Kitt Peak National Observatory. We detect 72 X-ray sources in a ~17 arcmin x 17 arcmin region with a ~68 ks ACIS exposure, for which we conduct follow-up NIR imaging observations in a concentric ~11 arcmin x 11 arcmin region with FLAMINGOS down to m_Ks ~ 17 mag. Twelve X-ray sources have NIR or optical counterparts. By plotting X-ray mean energy versus NIR to X-ray flux ratio, the X-ray sources are clearly separated into two groups. The X-ray spectral and temporal features as well as NIR magnitudes and colors indicate that one group mainly consists of young stellar objects (YSOs) in the cloud and the other of background extragalactic sources. Ten X-ray-emitting YSO candidates are thus newly identified, which are low-mass or brown dwarf mass sources from their NIR magnitudes. In addition, a possible X-ray signal is found from a mid-infrared protostar L1448 IRS 3(A). The lack of detection of this source in our deep NIR images indicates that this source has a very steep spectral slope of > 3.2 in 2--10 micron.

  15. Emission of Radio Waves in Gamma Ray Bursts and Axionic Boson Stars

    E-Print Network [OSTI]

    Aiichi Iwazaki

    1999-08-26

    We point out that the bursts of photons with the energy of the axion mass may appear coincidentally with gamma ray bursts if the gamma ray bursts are caused by collisions between neutron stars and axionic boson stars. In this mechanism, jets are formed in the collisions with large Lorentz factors $\\geq 10^2$. We explain qualitatively time-dependent complex structures of gamma ray bursts as well as the large energy problem. Therefore, with detection of the monochromatic photons we can test the model and determine the axion mass.

  16. THE DIVERSE HOT GAS CONTENT AND DYNAMICS OF OPTICALLY SIMILAR LOW-MASS ELLIPTICAL GALAXIES

    SciTech Connect (OSTI)

    Bogdan, Akos; David, Laurence P.; Jones, Christine; Forman, William R.; Kraft, Ralph P., E-mail: abogdan@cfa.harvard.edu [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States)

    2012-10-10

    The presence of hot X-ray-emitting gas is ubiquitous in massive early-type galaxies. However, much less is known about the content and physical status of the hot X-ray gas in low-mass ellipticals. In the present paper, we study the X-ray gas content of four low-mass elliptical galaxies using archival Chandra X-ray observations. The sample galaxies, NGC 821, NGC 3379, NGC 4278, and NGC 4697, have approximately identical K-band luminosities, and hence stellar masses, yet their X-ray appearance is strikingly different. We conclude that the unresolved emission in NGC 821 and NGC 3379 is built up from a multitude of faint compact objects, such as coronally active binaries and cataclysmic variables. Despite the non-detection of X-ray gas, these galaxies may host low density, and hence low luminosity, X-ray gas components, which undergo an outflow driven by a Type Ia supernova (SN Ia). We detect hot X-ray gas with a temperature of kT {approx} 0.35 keV in NGC 4278, the component of which has a steeper surface brightness distribution than the stellar light. Within the central 50'' ({approx}3.9 kpc), the estimated gas mass is {approx}3 Multiplication-Sign 10{sup 7} M{sub Sun }, implying a gas mass fraction of {approx}0.06%. We demonstrate that the X-ray gas exhibits a bipolar morphology in the northeast-southwest direction, indicating that it may be outflowing from the galaxy. The mass and energy budget of the outflow can be maintained by evolved stars and SNe Ia, respectively. The X-ray gas in NGC 4697 has an average temperature of kT {approx} 0.3 keV and a significantly broader distribution than the stellar light. The total gas mass within 90'' ({approx}5.1 kpc) is {approx}2.1 Multiplication-Sign 10{sup 8} M{sub Sun }, hence the gas mass fraction is {approx}0.4%. Based on the distribution and physical parameters of the X-ray gas, we conclude that it is most likely in hydrostatic equilibrium, although a subsonic outflow may be present.

  17. Static-light meson masses from twisted mass lattice QCD

    E-Print Network [OSTI]

    Static-light meson masses from twisted mass lattice QCD Karl Jansen, Chris Michael, Andrea Shindler of Groningen. · Spain: University of Valencia. · Switzerland: University of Bern. Marc Wagner, "Static-light meson masses from twisted mass lattice QCD", July 16, 2008 #12;Introduction · Static-light meson

  18. A correlation between hard gamma-ray sources and cosmic voids along the line of sight

    SciTech Connect (OSTI)

    Furniss, A.; Sutter, P. M.; Primack, J. R.; Dominguez, A.

    2014-11-25

    We estimate the galaxy density along lines of sight to hard extragalactic gamma-ray sources by correlating source positions on the sky with a void catalog based on the Sloan Digital Sky Survey (SDSS). Extragalactic gamma-ray sources that are detected at very high energy (VHE; E > 100 GeV) or have been highlighted as VHE-emitting candidates in the Fermi Large Area Telescope hard source catalog (together referred to as “VHE-like” sources) are distributed along underdense lines of sight at the 2.4#27; level. There is also a less suggestive correlation for the Fermi hard source population (1.7#27;). A correlation between 10-500 GeV flux and underdense fraction along the line of sight for VHE-like and Fermi hard sources is found at 2.4#27; and 2.6#27;, calculated from the Pearson correlation coefficients of r = 0.57 and 0.47, respectively. The preference for underdense sight lines is not displayed by gamma-ray emitting galaxies within the second Fermi catalog, containing sources detected above 100 MeV, or the SDSS DR7 quasar catalog. We investigate whether this marginal correlation might be a result of lower extragalactic background light (EBL) photon density within the underdense regions and find that, even in the most extreme case of a entirely underdense sight line, the EBL photon density is only 2% less than the nominal EBL density. Translating this into gamma-ray attenuation along the line of sight for a highly attenuated source with opacity #28;(E, z) #24; 5, we estimate that the attentuation of gamma-rays decreases no more than 10%. This decrease, although non-neglible, is unable to account for the apparent hard source correlation with underdense lines of sight.

  19. A correlation between hard gamma-ray sources and cosmic voids along the line of sight

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Furniss, A.; Sutter, P. M.; Primack, J. R.; Dominguez, A.

    2014-11-25

    We estimate the galaxy density along lines of sight to hard extragalactic gamma-ray sources by correlating source positions on the sky with a void catalog based on the Sloan Digital Sky Survey (SDSS). Extragalactic gamma-ray sources that are detected at very high energy (VHE; E > 100 GeV) or have been highlighted as VHE-emitting candidates in the Fermi Large Area Telescope hard source catalog (together referred to as “VHE-like” sources) are distributed along underdense lines of sight at the 2.4? level. There is a less suggestive correlation for the Fermi hard source population (1.7?). A correlation between 10-500 GeV fluxmore »and underdense fraction along the line of sight for VHE-like and Fermi hard sources is found at 2.4? and 2.6?, calculated from the Pearson correlation coefficients of r = 0.57 and 0.47, respectively. The preference for underdense sight lines is not displayed by gamma-ray emitting galaxies within the second Fermi catalog, containing sources detected above 100 MeV, or the SDSS DR7 quasar catalog. We investigate whether this marginal correlation might be a result of lower extragalactic background light (EBL) photon density within the underdense regions and find that, even in the most extreme case of a entirely underdense sight line, the EBL photon density is only 2% less than the nominal EBL density. Translating this into gamma-ray attenuation along the line of sight for a highly attenuated source with opacity ?(E, z) ~ 5, we estimate that the attentuation of gamma-rays decreases no more than 10%. This decrease, although non-neglible, is unable to account for the apparent hard source correlation with underdense lines of sight.« less

  20. Engineering rock mass classifications

    SciTech Connect (OSTI)

    Bieniawski, Z.T.

    1989-01-01

    This book is a reference on rock mass classification, consolidating into one handy source information widely scattered through the literature. Includes new, unpublished material and case histories. Presents the fundamental concepts of classification schemes and critically appraises their practical application in industrial projects such as tunneling and mining.

  1. Analytical mass spectrometry. Abstracts

    SciTech Connect (OSTI)

    Not Available

    1990-12-31

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  2. Analytical mass spectrometry

    SciTech Connect (OSTI)

    Not Available

    1990-01-01

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  3. Deuterium Pellet Mass Redistribution

    E-Print Network [OSTI]

    Budny, Robert

    Deuterium Pellet Mass Redistribution G L Schmidt, S Jardin, E Fredrickson, G Taylor P2.10P2 ·Pellets of solid hydrogen are used routinely for plasma fuelling and perturbation studies in tokamak discharges.[1]. ·The pellet source function determines to a large extent the pellet's effectiveness either

  4. Residential Thermal Mass Construction 

    E-Print Network [OSTI]

    Thieken, J. S.

    1988-01-01

    The southwest has long known the value of building homes with high mass materials. The ancient Pueblo Indians found that by using "adobe" they could capture the energy necessary to survive the harsh desert climate. Our ancestors knew that a heavy...

  5. Dimensionality and noise in energy selective x-ray imaging

    SciTech Connect (OSTI)

    Alvarez, Robert E.

    2013-11-15

    Purpose: To develop and test a method to quantify the effect of dimensionality on the noise in energy selective x-ray imaging.Methods: The Cramèr-Rao lower bound (CRLB), a universal lower limit of the covariance of any unbiased estimator, is used to quantify the noise. It is shown that increasing dimensionality always increases, or at best leaves the same, the variance. An analytic formula for the increase in variance in an energy selective x-ray system is derived. The formula is used to gain insight into the dependence of the increase in variance on the properties of the additional basis functions, the measurement noise covariance, and the source spectrum. The formula is also used with computer simulations to quantify the dependence of the additional variance on these factors. Simulated images of an object with three materials are used to demonstrate the trade-off of increased information with dimensionality and noise. The images are computed from energy selective data with a maximum likelihood estimator.Results: The increase in variance depends most importantly on the dimension and on the properties of the additional basis functions. With the attenuation coefficients of cortical bone, soft tissue, and adipose tissue as the basis functions, the increase in variance of the bone component from two to three dimensions is 1.4 × 10{sup 3}. With the soft tissue component, it is 2.7 × 10{sup 4}. If the attenuation coefficient of a high atomic number contrast agent is used as the third basis function, there is only a slight increase in the variance from two to three basis functions, 1.03 and 7.4 for the bone and soft tissue components, respectively. The changes in spectrum shape with beam hardening also have a substantial effect. They increase the variance by a factor of approximately 200 for the bone component and 220 for the soft tissue component as the soft tissue object thickness increases from 1 to 30 cm. Decreasing the energy resolution of the detectors increases the variance of the bone component markedly with three dimension processing, approximately a factor of 25 as the resolution decreases from 100 to 3 bins. The increase with two dimension processing for adipose tissue is a factor of two and with the contrast agent as the third material for two or three dimensions is also a factor of two for both components. The simulated images show that a maximum likelihood estimator can be used to process energy selective x-ray data to produce images with noise close to the CRLB.Conclusions: The method presented can be used to compute the effects of the object attenuation coefficients and the x-ray system properties on the relationship of dimensionality and noise in energy selective x-ray imaging systems.

  6. Gamma ray bursts in their historic context

    E-Print Network [OSTI]

    Trimble, V

    2004-01-01

    Gamma Ray Bursts In Their Historic Context Virginia TrimbleMD 20742 USA Abstract. Gamma ray bursts remained essentiallyalso applies to the gamma ray bursts. First, an observation

  7. X-Ray Data Booklet X-RAY DATA BOOKLET

    E-Print Network [OSTI]

    X-Ray Data Booklet X-RAY DATA BOOKLET Center for X-ray Optics and Advanced Light Source Lawrence Electromagnetic Relations Radioactivity and Radiation Protection Useful Formulas CXRO Home | ALS Home | LBL Home in PDF format Data Booklet Authors CXRO Home | ALS Home | LBL Home Privacy and Security Notice Please

  8. Galaxy Cluster Virial Masses and Omega

    E-Print Network [OSTI]

    Carlberg; Yee; Ellingson; Abraham; Gravel; Morris; Pritchet

    1995-09-06

    To re-examine the rich cluster $\\Omega$ value the CNOC Cluster Survey has observed 16 high X-ray luminosity clusters in the redshift range 0.17 to 0.55, obtaining approximately 2600 velocities in their fields. Directly adding all the K and evolution corrected $r$ band light to $M_r(0)=-18.5$, about $0.2L_\\ast$, and correcting for the light below the limit, the average mass-to-light ratio of the clusters is $283\\pm27h\\msun/\\lsun$ and the average mass per galaxy is $3.5\\pm0.4\\times10^{12}h^{-1}\\msun$. The clusters are consistent with having a universal $M_v/L$ value (within the errors of about 20\\%) independent of their velocity dispersion, mean color of their galaxies, blue galaxy content, redshift, or mean interior density. Using field galaxies within the same data set, with the same corrections, we find that the closure mass-to-light, $\\rho_c/j$, is $1160\\pm130h\\msun/\\lsun$ and the closure mass per galaxy, $\\rho_c/\\phi(>0.2L_\\ast)$, is $13.2\\pm1.9\\times10^{12}h^{-1}\\msun$. Under the assumptions that the galaxies are distributed like the mass and that the galaxy luminosities and numbers are statistically conserved, which these data indirectly support, $\\Omega_0=0.20\\pm0.04\\pm0.09$ where the errors are, respectively, the $1\\sigma$ internal and an estimate of the $1\\sigma$ systematic error resulting from the luminosity normalization.

  9. Oscillations During Thermonuclear X-ray Bursts: A New Probe of Neutron Stars

    E-Print Network [OSTI]

    Tod E. Strohmayer

    1999-11-19

    Observations of thermonuclear (Type I) X-ray bursts from neutron stars in low mass X-ray binaries (LMXB) with the Rossi X-ray Timing Explorer (RXTE) have revealed large amplitude, high coherence X-ray brightness oscillations with frequencies in the 300 - 600 Hz range. Substantial spectral and timing evidence point to rotational modulation of the X-ray burst flux as the cause of these oscillations, and it is likely that they reveal the spin frequencies of neutron stars in LMXB from which they are detected. Here I review the status of our knowledge of these oscillations and describe how they can be used to constrain the masses and radii of neutron stars as well as the physics of thermonuclear burning on accreting neutron stars.

  10. Constraints on jet X-ray emission in low/hard state X-ray binaries

    E-Print Network [OSTI]

    Thomas J. Maccarone

    2005-03-31

    We show that the combination of the similarities between the X-ray properties of low luminosity accreting black holes and accreting neutron stars, combined with the differences in their radio properties argues that the X-rays from these systems are unlikely to be formed in the relativistic jets. Specifically, the spectra of extreme island state neutron stars and low/hard state black holes are known to be indistinguishable, while the power spectra from these systems are known to show only minor differences beyond what would be expected from scaling the characteristic variability frequencies by the mass of the compact object. The spectral and temporal similarities thus imply a common emission mechanism that has only minor deviations from having all key parameters scaling linearly with the mass of the compact object, while we show that this is inconsistent with the observations that the radio powers of neutron stars are typically about 30 times lower than those of black holes at the same X-ray luminosity. We also show that an abrupt luminosity change would be expected when a system makes a spectral state transition from a radiatively inefficient jet dominated accretion flow to a thin disk dominated flow, but that such a change is not seen.

  11. Cosmological Implications and Physical Properties of an X-Ray Flux-Limited Sample of Galaxy Clusters

    E-Print Network [OSTI]

    Thomas H. Reiprich

    2003-08-08

    The original abstract significantly exceeds the space available here, so here's a brief summary. The abstract is similar to the abstract of astro-ph/0111285 (ApJ, 567, 716) which describes the X-ray galaxy cluster sample HIFLUGCS, the X-ray luminosity--gravitational mass relation, the cluster mass function, and the derived cosmological constraints. Additionally, the fraction of the total gravitating mass in the universe which is contained in intracluster gas is quantified. Furthermore, physical properties of the cluster sample have been studied and analyses of relations between different cluster parameters (including the gas mass fraction, gas temperature, X-ray luminosity, gas mass, gravitational mass, beta, and core radius) are discussed. Also, results from an analysis of XMM-Newton performance verification phase data of Abell 1835 are described.

  12. Sensitivity of the FERMI Detectors to Gamma-Ray Bursts from Evaporating Primordial Black Holes (PBHs)

    E-Print Network [OSTI]

    T. N. Ukwatta; Jane H. MacGibbon; W. C. Parke; K. S. Dhuga; S. Rhodes; A. Eskandarian; N. Gehrels; L. Maximon; D. C. Morris

    2010-03-23

    Primordial Black Holes (PBHs), which may have been created in the early Universe, are predicted to be detectable by their Hawking radiation. The Fermi Gamma-ray Space Telescope observatory offers increased sensitivity to the gamma-ray bursts produced by PBHs with an initial mass of $\\sim 5\\times 10^{14}$ g expiring today. PBHs are candidate progenitors of unidentified Gamma-Ray Bursts (GRBs) that lack X-ray afterglow. We propose spectral lag, which is the temporal delay between the high and low energy pulses, as an efficient method to identify PBH evaporation events with the Fermi Large Area Telescope (LAT).

  13. Fluctuation X-Ray Scattering

    SciTech Connect (OSTI)

    Saldin, PI: D. K.; Co-I's: J. C. H. Spence and P. Fromme

    2013-01-25

    The work supported by the grant was aimed at developing novel methods of finding the structures of biomolecules using x-rays from novel sources such as the x-ray free electron laser and modern synchrotrons

  14. The mass function of high redshift seed black holes

    E-Print Network [OSTI]

    Giuseppe Lodato; Priyamvada Natarajan

    2007-02-13

    In this paper we derive the mass function of seed black holes that result from the central mass concentrated via disc accretion in collapsed haloes at redshift $z\\approx 15$. Using standard arguments including stability, we show that these pre-galactic discs can assemble a significant mass concentration in the inner regions, providing fuel for the formation and initial growth of super-massive black holes. Assuming that these mass concentrations do result in central seed black holes, we determine the mass distribution of these seeds as a function of key halo properties. The seed mass distribution determined here turns out to be asymmetric and skewed to higher masses. Starting with these initial seeds, building up to $10^9$ solar masses by $z = 6$ to power the bright quasars is not a problem in the standard LCDM cosmogony. These seed black holes in gas rich environments are likely to grow into the supermassive black holes at later times via mergers and accretion. Gas accretion onto these seeds at high redshift will produce miniquasars that likely play an important role in the reionization of the Universe. Some of these seed black holes on the other hand could be wandering in galaxy haloes as a consequence of frequent mergers, powering the off-nuclear ultra-luminous X-ray sources detected in nearby galaxies.

  15. Riddle of the Neutrino Mass

    E-Print Network [OSTI]

    A. Yu. Smirnov

    2015-02-16

    We discuss some known approaches and results as well as few new ideas concerning origins and nature of neutrino mass. The key issues include (i) connections of neutrino and charged fermions masses, relation between masses and mixing, energy scale of new physics behind neutrino mass where possibilities spread from the Planck and GUT masses down to a sub-eV scale. The data hint two different new physics involved in generation of neutrino mass. Determination of the CP phase as well as mass hierarchy can play important role in identification of new physics. It may happen that sterile neutrinos provide the key to resolve the riddle.

  16. Riddle of the Neutrino Mass

    E-Print Network [OSTI]

    Smirnov, A Yu

    2015-01-01

    We discuss some known approaches and results as well as few new ideas concerning origins and nature of neutrino mass. The key issues include (i) connections of neutrino and charged fermions masses, relation between masses and mixing, energy scale of new physics behind neutrino mass where possibilities spread from the Planck and GUT masses down to a sub-eV scale. The data hint two different new physics involved in generation of neutrino mass. Determination of the CP phase as well as mass hierarchy can play important role in identification of new physics. It may happen that sterile neutrinos provide the key to resolve the riddle.

  17. Twisted mass finite volume effects

    SciTech Connect (OSTI)

    Colangelo, Gilberto; Wenger, Urs; Wu, Jackson M. S.

    2010-08-01

    We calculate finite-volume effects on the pion masses and decay constant in twisted mass lattice QCD at finite lattice spacing. We show that the lighter neutral pion in twisted mass lattice QCD gives rise to finite-volume effects that are exponentially enhanced when compared to those arising from the heavier charged pions. We demonstrate that the recent two flavor twisted mass lattice data can be better fitted when twisted mass effects in finite-volume corrections are taken into account.

  18. X-ray afterglows from gamma-ray bursts

    E-Print Network [OSTI]

    M. Tavani

    1997-03-24

    We consider possible interpretations of the recently detected X- ray afterglow from the gamma-ray burst source GRB 970228. Cosmological and Galactic models of gamma-ray bursts predict different flux and spectral evolution of X-ray afterglows. We show that models based on adiabatic expansion of relativistic forward shocks require very efficient particle energization or post-burst re-acceleration during the expansion. Cooling neutron star models predict a very distinctive spectral and flux evolution that can be tested in current X-ray data.

  19. Tunable X-ray source

    DOE Patents [OSTI]

    Boyce, James R. (Williamsburg, VA)

    2011-02-08

    A method for the production of X-ray bunches tunable in both time and energy level by generating multiple photon, X-ray, beams through the use of Thomson scattering. The method of the present invention simultaneously produces two X-ray pulses that are tunable in energy and/or time.

  20. Galactic cosmic rays and nucleosynthesis

    SciTech Connect (OSTI)

    Kiener, Juergen [CSNSM, CNRS-IN2P3 and Universite Paris-Sud, Bat. 104-108, 91405 Orsay Campus (France)

    2010-03-01

    The nucleosynthesis of the light elements Li, Be and B by galactic cosmic rays is presented. Observations of cosmic rays and the nuclear reactions responsible for Li, Be and B nucleosynthesis are described, followed by some words on propagation. At the end, some open questions concerning galactic cosmic rays are discussed.

  1. Nanoscale mass conveyors

    DOE Patents [OSTI]

    Regan, Brian C. (Oakland, CA); Aloni, Shaul (Albany, CA); Zettl, Alexander K. (Kensington, CA)

    2008-03-11

    A mass transport method and device for individually delivering chargeable atoms or molecules from source particles is disclosed. It comprises a channel; at least one source particle of chargeable material fixed to the surface of the channel at a position along its length; a means of heating the channel; and a means for applying an controllable electric field along the channel, whereby the device transports the atoms or molecules along the channel in response to applied electric field. In a preferred embodiment, the mass transport device will comprise a multiwalled carbon nanotube (MWNT), although other one dimensional structures may also be used. The MWNT or other structure acts as a channel for individual or small collections of atoms due to the atomic smoothness of the material. Also preferred is a source particle of a metal such as indium. The particles move by dissociation into small units, in some cases, individual atoms. The particles are preferably less than 100 nm in size.

  2. A celestial gamma-ray foreground due to the albedo of small solar system bodies and a remote probe of the interstellar cosmic ray spectrum

    SciTech Connect (OSTI)

    Moskalenko, Igor V.; Porter, Troy A.; Digel, Seth W.; Michelson, Peter F.; Ormes, Jonathan F.

    2007-12-17

    We calculate the {gamma}-ray albedo flux from cosmic-ray (CR) interactions with the solid rock and ice in Main Belt asteroids and Kuiper Belt objects (KBOs) using the Moon as a template. We show that the {gamma}-ray albedo for the Main Belt and Kuiper Belt strongly depends on the small-body mass spectrum of each system and may be detectable by the forthcoming Gamma Ray Large Area Space Telescope (GLAST). The orbits of the Main Belt asteroids and KBOs are distributed near the ecliptic, which passes through the Galactic center and high Galactic latitudes. If detected, the {gamma}-ray emission by the Main Belt and Kuiper Belt has to be taken into account when analyzing weak {gamma}-ray sources close to the ecliptic, especially near the Galactic center and for signals at high Galactic latitudes, such as the extragalactic {gamma}-ray emission. Additionally, it can be used to probe the spectrum of CR nuclei at close-to-interstellar conditions, and the mass spectrum of small bodies in the Main Belt and Kuiper Belt. The asteroid albedo spectrum also exhibits a 511 keV line due to secondary positrons annihilating in the rock. This may be an important and previously unrecognized celestial foreground for the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of the Galactic 511 keV line emission including the direction of the Galactic center.

  3. HIGEE Mass Transfer 

    E-Print Network [OSTI]

    Mohr, R. J.; Fowler, R.

    1986-01-01

    compared with other more conventional mass transfer equipment, will show up to advantage at reasonably large capacity but compare poorly for low capacity duties. (3) Capacity and separation capability (i.e. number of stages) in a HIGEE... are not independent variables, because diameter features in both. If the casing dimensions, OD and axial length, are arbitrarily fixed; then for a duty requiring a large number of stages the packing thickness will be greater and the ID correspondingly smaller...

  4. Electrospray Ionization Mass Spectrometry

    SciTech Connect (OSTI)

    Kelly, Ryan T.; Marginean, Ioan; Tang, Keqi

    2014-06-13

    Electrospray Ionization (ESI) is a process whereby gas phase ions are created from molecules in solution. As a solution exits a narrow tube in the presence of a strong electric field, an aerosol of charged droplets are is formed that produces gas phase ions as they it desolvates. ESI-MS comprises the creation of ions by ESI and the determination of their mass to charge ratio (m/z) by MS.

  5. Solar panels as cosmic-ray detectors

    E-Print Network [OSTI]

    Stella, Carlo; Assis, Pedro; Brogueira, Pedro; Santo, Catarina Espirito; Goncalves, Patricia; Pimenta, Mario; De Angelis, Alessandro

    2014-01-01

    Due to fundamental limitations of accelerators, only cosmic rays can give access to centre-of- mass energies more than one order of magnitude above those reached at the LHC. In fact, extreme energy cosmic rays (1018 eV - 1020 eV) are the only possibility to explore the 100 TeV energy scale in the years to come. This leap by one order of magnitude gives a unique way to open new horizons: new families of particles, new physics scales, in-depth investigations of the Lorentz symmetries. However, the flux of cosmic rays decreases rapidly, being less than one particle per square kilometer per year above 1019 eV: one needs to sample large surfaces. A way to develop large-effective area, low cost, detectors, is to build a solar panel-based device which can be used in parallel for power generation and Cherenkov light detection. Using solar panels for Cherenkov light detection would combine power generation and a non-standard detection device.

  6. The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

    E-Print Network [OSTI]

    A. U. Abeysekara; R. Alfaro; C. Alvarez; J. D. Alvarez; R. Arceo; J. C. Arteaga-Velazquez; H. A. Ayala Solares; A. S. Barber; B. M. Baughman; N. Bautista-Elivar; J. Becerra Gonzalez; E. Belmont; S. Y. BenZvi; D. Berley; M. Bonilla Rosales; J. Braun; R. A. Caballero-Lopez; K. S. Caballero-Mora; A. Carraminana; M. Castillo; U. Cotti; J. Cotzomi; E. de la Fuente; C. De Leon; T. DeYoung; R. Diaz Hernandez; L. Diaz-Cruz; J. C. Diaz-Velez; B. L. Dingus; M. A. DuVernois; R. W. Ellsworth; S. F. E.; D. W. Fiorino; N. Fraija; A. Galindo; F. Garfias; M. M. Gonzalez; J. A. Goodman; V. Grabski; M. Gussert; Z. Hampel-Arias; J. P. Harding; C. M. Hui; P. Huentemeyer; A. Imran; A. Iriarte; P. Karn; D. Kieda; G. J. Kunde; A. Lara; R. J. Lauer; W. H. Lee; D. Lennarz; H. Leon Vargas; E. C. Linares; J. T. Linnemann; M. Longo; R. Luna-Garcia; A. Marinelli; H. Martinez; O. Martinez; J. Martinez-Castro; J. A. J. Matthews; J. McEnery; E. Mendoza Torres; P. Miranda-Romagnoli; E. Moreno; M. Mostafa; L. Nellen; M. Newbold; R. Noriega-Papaqui; T. Oceguera-Becerra; B. Patricelli; R. Pelayo; E. G. Perez-Perez; J. Pretz; C. Riviere; D. Rosa-Gonzalez; J. Ryan; H. Salazar; F. Salesa; A. Sandoval; M. Schneider; S. Silich; G. Sinnis; A. J. Smith; K. Sparks Woodle; R. W. Springer; I. Taboada; P. A. Toale; K. Tollefson; I. Torres; T. N. Ukwatta; L. Villasenor; T. Weisgarber; S. Westerhoff; I. G. Wisher; J. Wood; G. B. Yodh; P. W. Younk; D. Zaborov; A. Zepeda; H. Zhou; K. N. Abazajian

    2014-12-09

    The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from non-luminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross-section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross-sections below thermal. HAWC should also be sensitive to non-thermal cross-sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross-section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.

  7. Radiative Gaugino Masses

    E-Print Network [OSTI]

    Glennys R. Farrar; Antonio Masiero

    1995-01-12

    We investigate the possibility that gauginos are massless at tree level and that the U(1) R-invariance is broken spontaneously by Higgs vevs, like the chiral symmetry of quarks in the standard model, or else explicitly by dimension 2 or 3 SUSY-breaking terms in the low energy effective Lagrangian. Gluino and lightest neutralino masses then depend on only a few parameters. For a SUSY-breaking scale <~ 400 GeV, the gluino and lightest neutralino have masses typically in the range 1/10 ~ 2 1/2 GeV. On the other hand, for a SUSY-breaking scale several TeV or larger, radiative contributions can yield gluino and lightest neutralino masses of O(50-300) GeV and O(10-30) GeV, respectively. As long as the Higgs vev is the only source of R-invariance breaking, or if SUSY breaking only appears in dimension 2 terms in the effective Lagrangian, the gluino is generically the lightest SUSY particle, modifying the usual phenomenology in interesting ways.

  8. Solution mass measurement

    SciTech Connect (OSTI)

    Ford, W.; Marshall, R.S.; Osborn, L.C.; Picard, R.; Thomas, C.C. Jr.

    1982-07-01

    This report describes the efforts to develop and demonstrate a solution mass measurement system for use at the Los Alamos Plutonium Facility. Because of inaccuracy of load cell measurements, our major effort was directed towards the pneumatic bubbler tube. The differential pressure between the air inlet to the bubbler tube and the glovebox interior is measured and is proportional to the solution mass in the tank. An inexpensive, reliable pressure transducer system for measuring solution mass in vertical, cylindrical tanks was developed, tested, and evaluated in a laboratory test bed. The system can withstand the over- and underpressures resulting from solution transfer operations and can prevent solution backup into the measurement pressure transducer during transfers. Drifts, noise, quantization error, and other effects limit the accuracy to 30 g. A transportable calibration system using a precision machined tank, pneumatic bubbler tubes, and a Ruska DDR 6000 electromanometer was designed, fabricated, tested, and evaluated. Resolution of the system is +-3.5 g out of 50 kg. The calibration error is 5 g, using room-temperature water as the calibrating fluid. Future efforts will be directed towards in-plant test and evaluation of the tank measurement systems. 16 figures, 3 tables.

  9. Top Mass and Properties

    E-Print Network [OSTI]

    Yen-Chu Chen

    2008-05-15

    The top quark was discovered in 1995. The top quark mass is now well measured at the Tevatron, with uncertainty getting below 1% of the top mass. The world average from last year was 170.9 $\\pm$ 1.8 GeV/$c^2$. The new CDF measurement is 172 $\\pm$ 1.2 (stat) $\\pm$ 1.5 (sys) GeV/$c^2$, and D0 will soon present a new measurement. The top quark mass is an important parameter in the Standard Model, and should be measured as precisely as possible. To learn more about the top quark observed and study possible new physics, other properties also should be measured. At the Tevatron, the charge of the top quark can be measured directly. Examples of other properties studied and reported in this presentation are W helicity, top decay branching ratio to b ($R_b$), searches for $t \\to H b$ and for flavor changing neutral current (FCNC). The results are all consistent with the Standard Model within current statistics. With significantly more data being collected at the Tevatron, precision measurements of the top properties are just starting.

  10. Combustor oscillation attenuation via the control of fuel-supply line dynamics

    DOE Patents [OSTI]

    Richards, G.A.; Gemmen, R.S.

    1998-09-22

    Combustion oscillation control in combustion systems using hydrocarbon fuels is provided by acoustically tuning a fuel-delivery line to a desired phase of the combustion oscillations for providing a pulse of a fuel-rich region at the oscillating flame front at each time when the oscillation produced pressure in the combustion chamber is in a low pressure phase. The additional heat release produced by burning such fuel-rich regions during low combustion chamber pressure effectively attenuates the combustion oscillations to a selected value. 9 figs.

  11. Combustor oscillation attenuation via the control of fuel-supply line dynamics

    SciTech Connect (OSTI)

    Richards, George A.; Gemmen, Randall S.

    1996-12-01

    Combustion oscillation control in combustion systems using hydrocarbon fuels is provided by acoustically tuning a fuel-delivery line to a desired phase of the combustion oscillations for providing a pulse of a fuel-rich region at the oscillating flame front at each time when the oscillation produced pressure in the combustion chamber is in a low pressure phase. The additional heat release produced by burning such fuel-rich regions during low combustion chamber pressure effectively attenuates the combustion oscillations to a selected value.

  12. Combustor oscillation attenuation via the control of fuel-supply line dynamics

    DOE Patents [OSTI]

    Richards, George A. (Morgantown, WV); Gemmen, Randall S. (Morgantown, WV)

    1998-01-01

    Combustion oscillation control in combustion systems using hydrocarbon fuels is provided by acoustically tuning a fuel-delivery line to a desired phase of the combustion oscillations for providing a pulse of a fuel-rich region at the oscillating flame front at each time when the oscillation produced pressure in the combustion chamber is in a low pressure phase. The additional heat release produced by burning such fuel-rich regions during low combustion chamber pressure effectively attenuates the combustion oscillations to a selected value.

  13. Attenuating Diesel Engine Emissions | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLosThe 26thIWalter H. Zinn, 1969 The8,April 2004ArgonneAttenuating

  14. An X-ray Reprocessing Model of Disk Thermal Emission in Type 1 Seyfert Galaxies

    E-Print Network [OSTI]

    James Chiang

    2002-02-12

    Using a geometry consisting of a hot central Comptonizing plasma surrounded by a thin accretion disk, we model the optical through hard X-ray spectral energy distributions of the type 1 Seyfert galaxies NGC 3516 and NGC 7469. As in the model proposed by Poutanen, Krolik, & Ryde for the X-ray binary Cygnus X-1 and later applied to Seyfert galaxies by Zdziarski, Lubi\\'nski, & Smith, feedback between the radiation reprocessed by the disk and the thermal Comptonization emission from the hot central plasma plays a pivotal role in determining the X-ray spectrum, and as we show, the optical and ultraviolet spectra as well. Seemingly uncorrelated optical/UV and X-ray light curves, similar to those which have been observed from these objects can be explained by variations in the size, shape, and temperature of the Comptonizing plasma. Furthermore, by positing a disk mass accretion rate which satisfies a condition for global energy balance between the thermal Comptonization luminosity and the power available from accretion, one can predict the spectral properties of the hard X-ray continuum above $\\sim 50$ keV in type 1 Seyfert galaxies. Forthcoming measurements of the hard X-ray continuum by more sensitive hard X-ray and soft $\\gamma$-ray telescopes, in conjunction with simultaneous optical, UV, and soft X-ray monitoring, will allow the mass accretion rates to be directly constrained for these sources in the context of this model.

  15. Proposed new accelerator design for homeland security x-ray applications

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Clayton, James; Shedlock, Daniel; Langeveld, Willem G.J.; Bharadwaj, Vinod; Nosochkov, Yuri

    2015-01-01

    Two goals for security scanning of cargo and freight are the ability to determine the type of material that is being imaged, and to do so at low radiation dose. One commonly used technique to determine the effective Z of the cargo is dual-energy imaging, i.e. imaging with different x-ray energy spectra. Another technique uses the fact that the transmitted x-ray spectrum itself also depends on the effective Z. Spectroscopy is difficult because the energy of individual x rays needs to be measured in a very high count-rate environment. Typical accelerators for security applications offer large but short bursts ofmore »x-rays, suitable for current-mode integrated imaging. In order to perform x-ray spectroscopy, a new accelerator design is desired that has the following features: 1) increased duty factor in order to spread out the arrival of x-rays at the detector array over time; 2) x-ray intensity modulation from one delivered pulse to the next by adjusting the accelerator electron beam instantaneous current so as to deliver adequate signal without saturating the spectroscopic detector; and 3) the capability to direct the (forward peaked) x-ray intensity towards high-attenuation areas in the cargo (“fan-beam-steering”). Current sources are capable of 0.1% duty factor, although usually they are operated at significantly lower duty factors (~0.04%), but duty factors in the range 0.4-1.0% are desired. The higher duty factor can be accomplished, e.g., by moving from 300 pulses per second (pps) to 1000 pps and/or increasing the pulse duration from a typical 4 ?s to 10 ?s. This paper describes initial R&D to examine cost effective modifications that could be performed on a typical accelerator for these purposes, as well as R&D for fan-beam steering.« less

  16. Proposed new accelerator design for homeland security x-ray applications

    SciTech Connect (OSTI)

    Clayton, James; Shedlock, Daniel; Langeveld, Willem G.J.; Bharadwaj, Vinod; Nosochkov, Yuri

    2015-01-01

    Two goals for security scanning of cargo and freight are the ability to determine the type of material that is being imaged, and to do so at low radiation dose. One commonly used technique to determine the effective Z of the cargo is dual-energy imaging, i.e. imaging with different x-ray energy spectra. Another technique uses the fact that the transmitted x-ray spectrum itself also depends on the effective Z. Spectroscopy is difficult because the energy of individual x rays needs to be measured in a very high count-rate environment. Typical accelerators for security applications offer large but short bursts of x-rays, suitable for current-mode integrated imaging. In order to perform x-ray spectroscopy, a new accelerator design is desired that has the following features: 1) increased duty factor in order to spread out the arrival of x-rays at the detector array over time; 2) x-ray intensity modulation from one delivered pulse to the next by adjusting the accelerator electron beam instantaneous current so as to deliver adequate signal without saturating the spectroscopic detector; and 3) the capability to direct the (forward peaked) x-ray intensity towards high-attenuation areas in the cargo (“fan-beam-steering”). Current sources are capable of 0.1% duty factor, although usually they are operated at significantly lower duty factors (~0.04%), but duty factors in the range 0.4-1.0% are desired. The higher duty factor can be accomplished, e.g., by moving from 300 pulses per second (pps) to 1000 pps and/or increasing the pulse duration from a typical 4 ?s to 10 ?s. This paper describes initial R&D to examine cost effective modifications that could be performed on a typical accelerator for these purposes, as well as R&D for fan-beam steering.

  17. Measurement of Mass and Spin of Black Holes with QPOs

    E-Print Network [OSTI]

    B. Aschenbach

    2007-10-18

    There are now four low mass X-ray binaries with black holes which show twin resonant-like HFQPOs. Similar QPOs might have been found in Sgr A*. I review the power spectral density distributions of the three X-ray flares and the six NIR flares published for Sgr A* so far, in order to look for more similarities than just the frequencies between the microquasar black holes and Sgr A*. The three X-ray flares of Sgr A* are re-analysed in an identical way and white noise probabilities from their power density distributions are given for the periods reported around 1100 s. Progress of the resonant theory using the anomalous orbital velocity effect is summarized.

  18. O Star X-ray Line Profiles Explained by Radiation Transfer in Inhomogeneous Stellar Wind

    E-Print Network [OSTI]

    L. M. Oskinova; A. Feldmeier; W. -R. Hamann

    2005-11-01

    It is commonly adopted that X-rays from O stars are produced deep inside the stellar wind, and transported outwards through the bulk of the expanding matter which attenuates the radiation and affects the shape of emission line profiles. The ability of Chandra and XMM-Newton to resolve these lines spectroscopically provided a stringent test for the theory of X-ray production. It turned out that none of the existing models was able to reproduce the observations consistently. The major caveat of these models was the underlying assumption of a smooth stellar wind. Motivated by the various observational evidence that the stellar winds are in fact structured, we present a 2-D model of a stochastic, inhomogeneous wind. The X-ray radiative transfer is derived for such media. It is shown that profiles from a clumped wind differ drastically from those predicted by conventional homogeneous models. We review the up-to-date observations of X-ray line profiles from stellar winds and present line fits obtained from the inhomogeneous wind model. The necessity to account for inhomogeneities in calculating the X-ray transport in massive star winds, including for HMXB is highlighted.

  19. Gamma-Ray Bursts as a Cosmic Window for Galaxy Evolution

    E-Print Network [OSTI]

    I. F. Mirabel; D. B. Sanders; E. Le Floc'h

    2000-04-03

    Present knowledge indicates that gamma-ray bursts are linked with massive stars. They will become invaluable probes of the early universe and galaxy formation. In the future, it will be possible to use gamma-ray bursts for two purposes: 1) to probe the history of massive star formation in the Universe by the rate of occurence of gamma-ray bursts, and 2) for the study of galaxy evolution at all lookback times by determining the nature of the galaxy hosts. Because gamma-rays are not attenuated by intervening dust and gas, the selection of the cosmic sites of massive star formation by this method is less affected by the biases associated with optical-uv surveys (e.g. UV-dropout techniques). Infrared and sub-millimeter follow up studies of the hosts of gamma-ray bursts may: 1) reveal a putative population of reddened ($R-K \\geq 4$) galaxies at high redshifts, and 2) detect very massive stars (population III) formed at $z \\geq$ 5.

  20. Geoelectrical Measurement of Multi-Scale Mass Transfer Parameters

    SciTech Connect (OSTI)

    Day-Lewis, Frederick; Singha, Kamini; Haggerty, Roy; Johnson, Tim; Binley, Andrew; Lane, John

    2014-01-16

    Mass transfer affects contaminant transport and is thought to control the efficiency of aquifer remediation at a number of sites within the Department of Energy (DOE) complex. An improved understanding of mass transfer is critical to meeting the enormous scientific and engineering challenges currently facing DOE. Informed design of site remedies and long-term stewardship of radionuclide-contaminated sites will require new cost-effective laboratory and field techniques to measure the parameters controlling mass transfer spatially and across a range of scales. In this project, we sought to capitalize on the geophysical signatures of mass transfer. Previous numerical modeling and pilot-scale field experiments suggested that mass transfer produces a geoelectrical signature—a hysteretic relation between sampled (mobile-domain) fluid conductivity and bulk (mobile + immobile) conductivity—over a range of scales relevant to aquifer remediation. In this work, we investigated the geoelectrical signature of mass transfer during tracer transport in a series of controlled experiments to determine the operation of controlling parameters, and also investigated the use of complex-resistivity (CR) as a means of quantifying mass transfer parameters in situ without tracer experiments. In an add-on component to our grant, we additionally considered nuclear magnetic resonance (NMR) to help parse mobile from immobile porosities. Including the NMR component, our revised study objectives were to: 1. Develop and demonstrate geophysical approaches to measure mass-transfer parameters spatially and over a range of scales, including the combination of electrical resistivity monitoring, tracer tests, complex resistivity, nuclear magnetic resonance, and materials characterization; and 2. Provide mass-transfer estimates for improved understanding of contaminant fate and transport at DOE sites, such as uranium transport at the Hanford 300 Area. To achieve our objectives, we implemented a 3-part research plan involving (1) development of computer codes and techniques to estimate mass-transfer parameters from time-lapse electrical data; (2) bench-scale experiments on synthetic materials and materials from cores from the Hanford 300 Area; and (3) field demonstration experiments at the DOE’s Hanford 300 Area. In a synergistic add-on to our workplan, we analyzed data from field experiments performed at the DOE Naturita Site under a separate DOE SBR grant, on which PI Day-Lewis served as co-PI. Techniques developed for application to Hanford datasets also were applied to data from Naturita. 1. Introduction The Department of Energy (DOE) faces enormous scientific and engineering challenges associated with the remediation of legacy contamination at former nuclear weapons production facilities. Selection, design and optimization of appropriate site remedies (e.g., pump-and-treat, biostimulation, or monitored natural attenuation) requires reliable predictive models of radionuclide fate and transport; however, our current modeling capabilities are limited by an incomplete understanding of multi-scale mass transfer—its rates, scales, and the heterogeneity of controlling parameters. At many DOE sites, long “tailing” behavior, concentration rebound, and slower-than-expected cleanup are observed; these observations are all consistent with multi-scale mass transfer [Haggerty and Gorelick, 1995; Haggerty et al., 2000; 2004], which renders pump-and-treat remediation and biotransformation inefficient and slow [Haggerty and Gorelick, 1994; Harvey et al., 1994; Wilson, 1997]. Despite the importance of mass transfer, there are significant uncertainties associated with controlling parameters, and the prevalence of mass transfer remains a point of debate [e.g., Hill et al., 2006; Molz et al., 2006] for lack of experimental methods to verify and measure it in situ or independently of tracer breakthrough. There is a critical need for new field-experimental techniques to measure mass transfer in-situ and estimate multi-scale and spatially variable mass-transfer parame

  1. Mass production of magnetic nickel nanoparticle in thermal plasma reactor

    SciTech Connect (OSTI)

    Kanhe, Nilesh S.; Nawale, Ashok B.; Bhoraskar, S. V.; Mathe, V. L.; Das, A. K.

    2014-04-24

    We report the mass production of Ni metal nanoparticles using dc transferred arc thermal plasma reactor by homogeneous gas phase condensation process. To increase the evaporation rate and purity of Ni nanoparticles small amount of hydrogen added along with argon in the plasma. Crystal structure analysis was done by using X-ray diffraction technique. The morphology of as synthesized nanoparticles was carried out using FESEM images. The magnetic properties were measured by using vibrating sample magnetometer at room temperature.

  2. X-ray lithography source

    DOE Patents [OSTI]

    Piestrup, Melvin A. (Woodside, CA); Boyers, David G. (Mountain View, CA); Pincus, Cary (Sunnyvale, CA)

    1991-01-01

    A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits. Foil stacks are bombarded with a high-energy electron beam of 25 to 250 MeV to produce a flux of soft X-rays of 500 eV to 3 keV. Methods of increasing the total X-ray power and making the cross section of the X-ray beam uniform are described. Methods of obtaining the desired X-ray-beam field size, optimum frequency spectrum and elminating the neutron flux are all described. A method of obtaining a plurality of station operation is also described which makes the process more efficient and economical. The satisfying of these issues makes transition radiation an exellent moderate-priced X-ray source for lithography.

  3. THREE NEW GALACTIC CENTER X-RAY SOURCES IDENTIFIED WITH NEAR-INFRARED SPECTROSCOPY

    SciTech Connect (OSTI)

    DeWitt, Curtis; Bandyopadhyay, Reba M.; Eikenberry, Stephen S.; Sarajedini, Ata; Sellgren, Kris; Blum, Robert; Olsen, Knut; Bauer, Franz E.

    2013-11-01

    We have conducted a near-infrared spectroscopic survey of 47 candidate counterparts to X-ray sources discovered by the Chandra X-Ray Observatory near the Galactic center (GC). Though a significant number of these astrometric matches are likely to be spurious, we sought out spectral characteristics of active stars and interacting binaries, such as hot, massive spectral types or emission lines, in order to corroborate the X-ray activity and certify the authenticity of the match. We present three new spectroscopic identifications, including a Be high-mass X-ray binary (HMXB) or a ? Cassiopeiae (Cas) system, a symbiotic X-ray binary, and an O-type star of unknown luminosity class. The Be HMXB/? Cas system and the symbiotic X-ray binary are the first of their classes to be spectroscopically identified in the GC region.

  4. Observational Tests of the Mass-Temperature Relation for Galaxy Clusters

    E-Print Network [OSTI]

    Donald J. Horner; Richard F. Mushotzky; Caleb A. Scharf

    1999-02-10

    We examine the relationship between the mass and x-ray gas temperature of galaxy clusters using data drawn from the literature. Simple theoretical arguments suggest that the mass of a cluster is related to the x-ray temperature as $M \\propto T_x^{3/2}$. Virial theorem mass estimates based on cluster galaxy velocity dispersions seem to be accurately described by this scaling with a normalization consistent with that predicted by the simulations of Evrard, Metzler, & Navarro (1996). X-ray mass estimates which employ spatially resolved temperature profiles also follow a $T_x^{3/2}$ scaling although with a normalization about 40% lower than that of the fit to the virial masses. However, the isothermal $\\beta$-model and x-ray surface brightness deprojection masses follow a steeper $\\propto T_x^{1.8-2.0}$ scaling. The steepness of the isothermal estimates is due to their implicitly assumed dark matter density profile of $\\rho(r) \\propto r^{-2}$ at large radii while observations and simulations suggest that clusters follow steeper profiles (e.g., $\\rho(r) \\propto r^{-2.4}$).

  5. Absolute Values of Neutrino Masses: Status and Prospects

    E-Print Network [OSTI]

    S. M. Bilenky; C. Giunti; J. A. Grifols; E. Masso

    2003-03-27

    Compelling evidences in favor of neutrino masses and mixing obtained in the last years in Super-Kamiokande, SNO, KamLAND and other neutrino experiments made the physics of massive and mixed neutrinos a frontier field of research in particle physics and astrophysics. There are many open problems in this new field. In this review we consider the problem of the absolute values of neutrino masses, which apparently is the most difficult one from the experimental point of view. We discuss the present limits and the future prospects of beta-decay neutrino mass measurements and neutrinoless double-beta decay. We consider the important problem of the calculation of nuclear matrix elements of neutrinoless double-beta decay and discuss the possibility to check the results of different model calculations of the nuclear matrix elements through their comparison with the experimental data. We discuss the upper bound of the total mass of neutrinos that was obtained recently from the data of the 2dF Galaxy Redshift Survey and other cosmological data and we discuss future prospects of the cosmological measurements of the total mass of neutrinos. We discuss also the possibility to obtain information on neutrino masses from the observation of the ultra high-energy cosmic rays (beyond the GZK cutoff). Finally, we review the main aspects of the physics of core-collapse supernovae, the limits on the absolute values of neutrino masses from the observation of SN1987A neutrinos and the future prospects of supernova neutrino detection.

  6. Heat and mass exchanger

    DOE Patents [OSTI]

    Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc J. (Princeton, NJ); Miller, Jeffrey A. (Hopewell, NJ); Tonon, Thomas (Princeton, NJ)

    2011-06-28

    A mass and heat exchanger includes at least one first substrate with a surface for supporting a continuous flow of a liquid thereon that either absorbs, desorbs, evaporates or condenses one or more gaseous species from or to a surrounding gas; and at least one second substrate operatively associated with the first substrate. The second substrate includes a surface for supporting the continuous flow of the liquid thereon and is adapted to carry a heat exchange fluid therethrough, wherein heat transfer occurs between the liquid and the heat exchange fluid.

  7. Heat and mass exchanger

    DOE Patents [OSTI]

    Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc J. (Princeton, NJ); Miller, Jeffrey A. (Hopewell, NJ); Tonon, Thomas (Princeton, NJ)

    2007-09-18

    A mass and heat exchanger includes at least one first substrate with a surface for supporting a continuous flow of a liquid thereon that either absorbs, desorbs, evaporates or condenses one or more gaseous species from or to a surrounding gas; and at least one second substrate operatively associated with the first substrate. The second substrate includes a surface for supporting the continuous flow of the liquid thereon and is adapted to carry a heat exchange fluid therethrough, wherein heat transfer occurs between the liquid and the heat exchange fluid.

  8. Dusty galaxies and the degeneracy between their dust distributions and the attenuation formula

    E-Print Network [OSTI]

    Penner, Kyle; Weiner, Benjamin; Inami, Hanae; Kartaltepe, Jeyhan; Pforr, Janine; Nayyeri, Hooshang; Kassin, Susan; Papovich, Casey; Pope, Alexandra

    2015-01-01

    Do spatial distributions of dust grains in galaxies have typical forms, as do spatial distributions of stars? We investigate whether or not the distributions resemble uniform foreground screens, as commonly assumed by the high-redshift galaxy community. We use rest-frame infrared, ultraviolet, and H$\\alpha$ line luminosities of dust-poor and dusty galaxies at z ~ 0 and z ~ 1 to compare measured H$\\alpha$ escape fractions with those predicted by the Calzetti attenuation formula. The predictions, based on UV escape fractions, overestimate the measured H$\\alpha$ escape fractions for all samples. The interpretation of this result for dust-poor z ~ 0 galaxies is that regions with ionizing stars have more dust than regions with nonionizing UV-emitting stars. Dust distributions for these galaxies are nonuniform. The interpretation of the overestimates for dusty galaxies at both redshifts is less clear. If the attenuation formula is inapplicable to these galaxies, perhaps the disagreements are unphysical; perhaps dus...

  9. Evaluating Transport and Attenuation of Inorganic Contaminants in the Vadose Zone for Aqueous Waste Disposal Sites

    SciTech Connect (OSTI)

    Truex, Michael J.; Oostrom, Martinus; Tartakovsky, Guzel D.

    2015-09-01

    An approach was developed for evaluating vadose zone transport and attenuation of aqueous wastes containing inorganic (non-volatile) contaminants that were disposed of at the land surface (i.e., directly to the ground in cribs, trenches, tile fields, etc.) and their effect on the underlying groundwater. The approach provides a structured method for estimating transport of contaminants through the vadose zone and the resulting temporal profile of groundwater contaminant concentrations. The intent of the approach is also to provide a means for presenting and explaining the results of the transport analysis in the context of the site-specific waste disposal conditions and site properties, including heterogeneities and other complexities. The document includes considerations related to identifying appropriate monitoring to verify the estimated contaminant transport and associated predictions of groundwater contaminant concentrations. While primarily intended for evaluating contaminant transport under natural attenuation conditions, the approach can also be applied to identify types of, and targets for, mitigation approaches in the vadose zone that would reduce the temporal profile of contaminant concentrations in groundwater, if needed.

  10. Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities

    SciTech Connect (OSTI)

    K. Ladwig

    2005-12-31

    The overall objective of this project was to evaluate the impact of key constituents captured from power plant air streams (principally arsenic and selenium) on the disposal and utilization of coal combustion products (CCPs). Specific objectives of the project were: (1) to develop a comprehensive database of field leachate concentrations at a wide range of CCP management sites, including speciation of arsenic and selenium, and low-detection limit analyses for mercury; (2) to perform detailed evaluations of the release and attenuation of arsenic species at three CCP sites; and (3) to perform detailed evaluations of the release and attenuation of selenium species at three CCP sites. Each of these objectives was accomplished using a combination of field sampling and laboratory analysis and experimentation. All of the methods used and results obtained are contained in this report. For ease of use, the report is subdivided into three parts. Volume 1 contains methods and results for the field leachate characterization. Volume 2 contains methods and results for arsenic adsorption. Volume 3 contains methods and results for selenium adsorption.

  11. Universal X-ray emissivity of the stellar population in early-type galaxies: unresolved X-ray sources in NGC 3379

    E-Print Network [OSTI]

    M. Revnivtsev; E. Churazov; S. Sazonov; W. Forman; C. Jones

    2008-06-27

    We use deep Chandra observations to measure the emissivity of the unresolved X-ray emission in the elliptical galaxy NGC 3379. After elimination of bright, low-mass X-ray binaries with luminosities >10^{36 erg/sec, we find that the remaining unresolved X-ray emission is characterized by an emissivity per unit stellar mass L_x/M_stars ~8.2x10^{27} erg/s/M_sun in the 0.5-2 keV energy band. This value is in good agreement with those previousely determined for the dwarf elliptical galaxy M32, the bulge of the spiral galaxy M31 and the Milky Way, as well as with the integrated X-ray emissivity of cataclysmic variables and coronally active binaries in the Solar neighborhood. This strongly suggests that i) the bulk of the unresolved X-ray emission in NGC 3379 is produced by its old stellar population and ii) the old stellar populations in all galaxies can be characterized by a universal value of X-ray emissivity per unit stellar mass or per unit K band luminosity.

  12. Theoretical mass loss rates of cool main-sequence stars

    E-Print Network [OSTI]

    V. Holzwarth; M. Jardine

    2006-11-14

    We develop a model for the wind properties of cool main-sequence stars, which comprises their wind ram pressures, mass fluxes, and terminal wind velocities. The wind properties are determined through a polytropic magnetised wind model, assuming power laws for the dependence of the thermal and magnetic wind parameters on the stellar rotation rate. We use empirical data to constrain theoretical wind scenarios, which are characterised by different rates of increase of the wind temperature, wind density, and magnetic field strength. Scenarios based on moderate rates of increase yield wind ram pressures in agreement with most empirical constraints, but cannot account for some moderately rotating targets, whose high apparent mass loss rates are inconsistent with observed coronal X-ray and magnetic properties. For fast magnetic rotators, the magneto-centrifugal driving of the outflow can produce terminal wind velocities far in excess of the surface escape velocity. Disregarding this aspect in the analyses of wind ram pressures leads to overestimations of stellar mass loss rates. The predicted mass loss rates of cool main-sequence stars do not exceed about ten times the solar value. Our results are in contrast with previous investigations, which found a strong increase of the stellar mass loss rates with the coronal X-ray flux. Owing to the weaker dependence, we expect the impact of stellar winds on planetary atmospheres to be less severe and the detectability of magnetospheric radio emission to be lower then previously suggested. Considering the rotational evolution of a one solar-mass star, the mass loss rates and the wind ram pressures are highest during the pre-main sequence phase.

  13. Top quark mass measurements

    SciTech Connect (OSTI)

    L. Cerrito

    2004-07-16

    Preliminary results on the measurement of the top quark mass at the Tevatron Collider are presented. In the dilepton decay channel, the CDF Collaboration measures m{sub t} = 175.0{sub -16.9}{sup +17.4}(stat.){+-}8.4(syst.) GeV/c{sup 2}, using a sample of {approx} 126 pb{sup -1} of proton-antiproton collision data at {radical}s = 1.96 TeV (Run II). In the lepton plus jets channel, the CDF Collaboration measures 177.5{sub -9.4}{sup +12.7}(stat.) {+-} 7.1(syst.) GeV/c{sup 2}, using a sample of {approx} 102 pb{sup -1} at {radical}s = 1.96 TeV. The D0 Collaboration has newly applied a likelihood technique to improve the analysis of {approx} 125 pb{sup -1} of proton-antiproton collisions at {radical}s = 1.8 TeV (Run I), with the result: m{sub t} = 180.1 {+-} 3.6(stat.) {+-}3.9(syst.) GeV/c{sup 2}. The latter is combined with all the measurements based on the data collected in Run I to yield the most recent and comprehensive experimental determination of the top quark mass: m{sub t} = 178.0 {+-} 2.7(stat.) {+-} 3.3(syst.) GeV/c{sup 2}.

  14. Mass Transport within Soils

    SciTech Connect (OSTI)

    McKone, Thomas E.

    2009-03-01

    Contaminants in soil can impact human health and the environment through a complex web of interactions. Soils exist where the atmosphere, hydrosphere, geosphere, and biosphere converge. Soil is the thin outer zone of the earth's crust that supports rooted plants and is the product of climate and living organisms acting on rock. A true soil is a mixture of air, water, mineral, and organic components. The relative proportions of these components determine the value of the soil for agricultural and for other human uses. These proportions also determine, to a large extent, how a substance added to soil is transported and/or transformed within the soil (Spositio, 2004). In mass-balance models, soil compartments play a major role, functioning both as reservoirs and as the principal media for transport among air, vegetation, surface water, deeper soil, and ground water (Mackay, 2001). Quantifying the mass transport of chemicals within soil and between soil and atmosphere is important for understanding the role soil plays in controlling fate, transport, and exposure to multimedia pollutants. Soils are characteristically heterogeneous. A trench dug into soil typically reveals several horizontal layers having different colors and textures. As illustrated in Figure 1, these multiple layers are often divided into three major horizons: (1) the A horizon, which encompasses the root zone and contains a high concentration of organic matter; (2) the B horizon, which is unsaturated, lies below the roots of most plants, and contains a much lower organic carbon content; and (3) the C horizon, which is the unsaturated zone of weathered parent rock consisting of bedrock, alluvial material, glacial material, and/or soil of an earlier geological period. Below these three horizons lies the saturated zone - a zone that encompasses the area below ground surface in which all interconnected openings within the geologic media are completely filled with water. Similarly to the unsaturated zone with three major horizons, the saturated zone can be further divided into other zones based on hydraulic and geologic conditions. Wetland soils are a special and important class in which near-saturation conditions exist most of the time. When a contaminant is added to or formed in a soil column, there are several mechanisms by which it can be dispersed, transported out of the soil column to other parts of the environment, destroyed, or transformed into some other species. Thus, to evaluate or manage any contaminant introduced to the soil column, one must determine whether and how that substance will (1) remain or accumulate within the soil column, (2) be transported by dispersion or advection within the soil column, (3) be physically, chemically, or biologically transformed within the soil (i.e., by hydrolysis, oxidation, etc.), or (4) be transported out of the soil column to another part of the environment through a cross-media transfer (i.e., volatilization, runoff, ground water infiltration, etc.). These competing processes impact the fate of physical, chemical, or biological contaminants found in soils. In order to capture these mechanisms in mass transfer models, we must develop mass-transfer coefficients (MTCs) specific to soil layers. That is the goal of this chapter. The reader is referred to other chapters in this Handbook that address related transport processes, namely Chapter 13 on bioturbation, Chapter 15 on transport in near-surface geological formations, and Chapter 17 on soil resuspention. This chapter addresses the following issues: the nature of soil pollution, composition of soil, transport processes and transport parameters in soil, transformation processes in soil, mass-balance models, and MTCs in soils. We show that to address vertical heterogeneity in soils in is necessary to define a characteristic scaling depth and use this to establish process-based expressions for soil MTCs. The scaling depth in soil and the corresponding MTCs depend strongly on (1) the composition of the soil and physical state of the soil, (2) the chemical and physic

  15. Determining the neutrino mass hierarchy

    SciTech Connect (OSTI)

    Parke, Stephen J.; /Fermilab

    2006-07-01

    In this proceedings I review the physics that future experiments will use to determine the neutrino mass hierarchy.

  16. Peak mass and dynamical friction

    E-Print Network [OSTI]

    A. Del Popolo; M. Gambera

    1995-06-09

    We show how the results given by several authors relatively to the mass of a density peak are changed when small scale substructure induced by dynamical friction are taken into account. The peak mass obtained is compared to the result of Peacock \\& Heavens (1990) and to the peak mass when dynamical friction is absent to show how these effects conspire to reduce the mass accreted by the peak.

  17. Energy Grasses for the Masses

    Broader source: Energy.gov [DOE]

    Breakout Session 1-D: The Pitch Energy Grasses for the Masses Jason Force, Chief Executive Officer, Iron Goat Technology, Inc.

  18. The HAWC Gamma-Ray Observatory: Observations of Cosmic Rays

    E-Print Network [OSTI]

    Abeysekara, A U; Alvarez, C; Álvarez, J D; Arceo, R; Arteaga-Velázquez, J C; Solares, H A Ayala; Barber, A S; Baughman, B M; Bautista-Elivar, N; Belmont, E; BenZvi, S Y; Berley, D; Rosales, M Bonilla; Braun, J; Caballero-Lopez, R A; Caballero-Mora, K S; Carramiñana, A; Castillo, M; Cotti, U; Cotzomi, J; de la Fuente, E; De León, C; DeYoung, T; Hernandez, R Diaz; Díaz-Vélez, J C; Dingus, B L; DuVernois, M A; Ellsworth, R W; Fernandez, A; Fiorino, D W; Fraija, N; Galindo, A; Garfias, F; González, L X; González, M M; Goodman, J A; Grabski, V; Gussert, M; Hampel-Arias, Z; Hui, C M; Hüntemeyer, P; Imran, A; Iriarte, A; Karn, P; Kieda, D; Kunde, G J; Lara, A; Lauer, R J; Lee, W H; Lennarz, D; Vargas, H León; Linares, E C; Linnemann, J T; Longo, M; Luna-GarcIa, R; Marinelli, A; Martinez, H; Martinez, O; Martínez-Castro, J; Matthews, J A J; Miranda-Romagnoli, P; Moreno, E; Mostafá, M; Nava, J; Nellen, L; Newbold, M; Noriega-Papaqui, R; Oceguera-Becerra, T; Patricelli, B; Pelayo, R; Pérez-Pérez, E G; Pretz, J; Rivière, C; Rosa-González, D; Salazar, H; Salesa, F; Sanchez, F E; Sandoval, A; Santos, E; Schneider, M; Silich, S; Sinnis, G; Smith, A J; Sparks, K; Springer, R W; Taboada, I; Toale, P A; Tollefson, K; Torres, I; Ukwatta, T N; Villaseñor, L; Weisgarber, T; Westerhoff, S; Wisher, I G; Wood, J; Yodh, G B; Younk, P W; Zaborov, D; Zepeda, A; Zhou, H

    2013-01-01

    We describe measurements of GeV and TeV cosmic rays with the High-Altitude Water Cherenkov Gamma-Ray Observatory, or HAWC. The measurements include the observation of the shadow of the moon; the observation of small-scale and large-scale angular clustering of the TeV cosmic rays; the prospects for measurement of transient solar events with HAWC; and the observation of Forbush decreases with the HAWC engineering array and HAWC-30.

  19. Exotic massive hadrons and ultrahigh energy cosmic rays

    SciTech Connect (OSTI)

    Albuquerque, I.F. [Department of Astronomy and Astrophysics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States)] [Department of Astronomy and Astrophysics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Farrar, G.R. [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08855 (United States)] [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08855 (United States); Kolb, E.W. [NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)] [NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); [Department of Astronomy and Astrophysics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637 (United States)

    1999-01-01

    We investigate the proposal that primary cosmic rays of energy above the Greisen-Zatsepin-Kuzmin cutoff are exotic massive strongly interacting particles (uhecrons). We study the properties of air showers produced by uhecrons and find that masses in excess of about 50 GeV are inconsistent with the highest energy event observed. We also estimate that with sufficient statistics a uhecron of mass as low as 10 GeV may be distinguished from a proton. {copyright} {ital 1998} {ital The American Physical Society}

  20. Linear electric field mass spectrometry

    DOE Patents [OSTI]

    McComas, D.J.; Nordholt, J.E.

    1992-12-01

    A mass spectrometer and methods for mass spectrometry are described. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field. 8 figs.

  1. X-Ray Diagnostics

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAbout /Two0PhotosPresentationsWorld's largest singleX-Ray

  2. Ultra high energy cosmic rays: the highest energy frontier

    E-Print Network [OSTI]

    Neto, João R T de Mello

    2015-01-01

    Ultra-high energy cosmic rays (UHECRs) are the highest energy messengers of the present universe, with energies up to $10^{20}$ eV. Studies of astrophysical particles (nuclei, electrons, neutrinos and photons) at their highest observed energies have implications for fundamental physics as well as astrophysics. The primary particles interact in the atmosphere and generate extensive air showers. Analysis of those showers enables one not only to estimate the energy, direction and most probable mass of the primary cosmic particles, but also to obtain information about the properties of their hadronic interactions at an energy more than one order of magnitude above that accessible with the current highest energy human-made accelerator. In this contribution we will review the state-of-the-art in UHECRs detection. We will present the leading experiments Pierre Auger Observatory and Telescope Array and discuss the cosmic ray energy spectrum, searches for directional anisotropy, studies of mass composition, the determ...

  3. Precision Spectroscopy of Pionic Atoms: From Pion Mass Evaluation to Tests of Chiral Perturbation Theory

    E-Print Network [OSTI]

    Martino Trassinelli

    2004-09-14

    Preliminary results of the strong interaction shift and width in pionic hydrogen ($\\pi H$) using an X-ray spectrometer with spherically bent crystals and CCDs as X-ray detector are presented. In the experiment at the Paul Scherrer Institute three different $(np\\to 1s)$ transitions in $\\pi H$ were measured. Moreover the pion mass measurement using the $(5 \\to 4)$ transitions in pionic nitrogen and muonic oxygen is presented

  4. DISCOVERY OF X-RAY EMISSION FROM YOUNG SUNS IN THE SMALL MAGELLANIC CLOUD

    SciTech Connect (OSTI)

    Oskinova, L. M.; Hainich, R. [Institute for Physics and Astronomy, University Potsdam, D-14476 Potsdam (Germany)] [Institute for Physics and Astronomy, University Potsdam, D-14476 Potsdam (Germany); Sun, W.; Chen, Y. [Department of Astronomy, Nanjing University, Nanjing, 210093 Jiangsu (China)] [Department of Astronomy, Nanjing University, Nanjing, 210093 Jiangsu (China); Evans, C. J. [UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)] [UK Astronomy Technology Centre, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Henault-Brunet, V. [Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom)] [Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Chu, Y.-H.; Gruendl, R. A. [Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States)] [Department of Astronomy, University of Illinois, 1002 West Green Street, Urbana, IL 61801 (United States); Gallagher, J. S. III [Department of Astronomy, University of Wisconsin-Madison, 5534 Sterling, 475 North Charter Street, Madison, WI 53706 (United States)] [Department of Astronomy, University of Wisconsin-Madison, 5534 Sterling, 475 North Charter Street, Madison, WI 53706 (United States); Guerrero, M. A. [Instituto de Astrofisica de Andalucia, IAA-CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain)] [Instituto de Astrofisica de Andalucia, IAA-CSIC, Glorieta de la Astronomia s/n, E-18008 Granada (Spain); Guedel, M. [Department of Astrophysics, University of Vienna, Tuerkenschanzstrasse 17, A-1180 Vienna (Austria)] [Department of Astrophysics, University of Vienna, Tuerkenschanzstrasse 17, A-1180 Vienna (Austria); Silich, S. [Instituto Nacional de Astrofisica Optica y Electronica, AP 51, 72000 Puebla (Mexico)] [Instituto Nacional de Astrofisica Optica y Electronica, AP 51, 72000 Puebla (Mexico); Naze, Y. [GAPHE, Departement AGO, Universite de Liege, Allee du 6 Aout 17, Bat. B5C, B-4000 Liege (Belgium)] [GAPHE, Departement AGO, Universite de Liege, Allee du 6 Aout 17, Bat. B5C, B-4000 Liege (Belgium); Reyes-Iturbide, J. [LATO-DCET/Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-000 Ilheus, BA (Brazil)] [LATO-DCET/Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, km 16, 45662-000 Ilheus, BA (Brazil)

    2013-03-01

    We report the discovery of extended X-ray emission within the young star cluster NGC 602a in the Wing of the Small Magellanic Cloud (SMC) based on observations obtained with the Chandra X-Ray Observatory. X-ray emission is detected from the cluster core area with the highest stellar density and from a dusty ridge surrounding the H II region. We use a census of massive stars in the cluster to demonstrate that a cluster wind or wind-blown bubble is unlikely to provide a significant contribution to the X-ray emission detected from the central area of the cluster. We therefore suggest that X-ray emission at the cluster core originates from an ensemble of low- and solar-mass pre-main-sequence (PMS) stars, each of which would be too weak in X-rays to be detected individually. We attribute the X-ray emission from the dusty ridge to the embedded tight cluster of the newborn stars known in this area from infrared studies. Assuming that the levels of X-ray activity in young stars in the low-metallicity environment of NGC 602a are comparable to their Galactic counterparts, then the detected spatial distribution, spectral properties, and level of X-ray emission are largely consistent with those expected from low- and solar-mass PMS stars and young stellar objects (YSOs). This is the first discovery of X-ray emission attributable to PMS stars and YSOs in the SMC, which suggests that the accretion and dynamo processes in young, low-mass objects in the SMC resemble those in the Galaxy.

  5. An X-ray Imaging Study of the Stellar Population in RCW49

    E-Print Network [OSTI]

    M. Tsujimoto; E. D. Feigelson; L. K. Townsley; P. S. Broos; K. V. Getman; J. Wang; G. P. Garmire; D. Baba; T. Nagayama; M. Tamura; E. B. Churchwell

    2007-05-04

    We present the results of a high-resolution X-ray imaging study of the stellar population in the Galactic massive star-forming region RCW49 and its central OB association Westerlund 2. We obtained a 40 ks X-ray image of a 17'x17' field using the Chandra X-ray Observatory and deep NIR images using the Infrared Survey Facility in a concentric 8'3x8'3 region. We detected 468 X-ray sources and identified optical, NIR, and Spitzer Space Telescope MIR counterparts for 379 of them. The unprecedented spatial resolution and sensitivity of the X-ray image, enhanced by optical and infrared imaging data, yielded the following results: (1) The central OB association Westerlund 2 is resolved for the first time in the X-ray band. X-ray emission is detected from all spectroscopically-identified early-type stars in this region. (2) Most (86%) X-ray sources with optical or infrared identifications are cluster members in comparison with a control field in the Galactic Plane. (3) A loose constraint (2--5 kpc) for the distance to RCW49 is derived from the mean X-ray luminosity of T Tauri stars. (4) The cluster X-ray population consists of low-mass pre--main-sequence and early-type stars as obtained from X-ray and NIR photometry. About 30 new OB star candidates are identified. (5) We estimate a cluster radius of 6'--7' based on the X-ray surface number density profiles. (6) A large fraction (90%) of cluster members are identified individually using complimentary X-ray and MIR excess emission. (7) The brightest five X-ray sources, two Wolf-Rayet stars and three O stars, have hard thermal spectra.

  6. The X-ray Telescope of the CAST Experiment

    E-Print Network [OSTI]

    R. Kotthaus; H. Braeuninger; P. Friedrich; R. Hartmann; D. Kang; M. Kuster; G. Lutz; L. Strueder

    2005-11-14

    The CERN Axion Solar Telescope (CAST) searches for solar axions employing a 9 Tesla superconducting dipole magnet equipped with 3 independent detection systems for X-rays from axion-photon conversions inside the 10 m long magnetic field. Results of the first 6 months of data taking in 2003 imply a 95 % CL upper limit on the axion-photon coupling constant of 1.16x10(-10) GeV(-1) for axion masses CAST is a X-ray telescope consisting of a Wolter I type mirror system and a fully depleted pn-CCD as focal plane detector. Exploiting the full potential of background suppression by focussing X-rays emerging from the magnet bore, the axion sensitivity obtained with telescope data taken in 2004, for the first time in a controlled laboratory experiment, will supersede axion constraints derived from stellar energy loss arguments.

  7. Miniature x-ray source

    DOE Patents [OSTI]

    Trebes, James E. (Livermore, CA); Stone, Gary F. (Livermore, CA); Bell, Perry M. (Tracy, CA); Robinson, Ronald B. (Modesto, CA); Chornenky, Victor I. (Minnetonka, MN)

    2002-01-01

    A miniature x-ray source capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature x-ray source comprises a compact vacuum tube assembly containing a cathode, an anode, a high voltage feedthru for delivering high voltage to the anode, a getter for maintaining high vacuum, a connection for an initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is highly x-ray transparent and made, for example, from boron nitride. The compact size and potential for remote operation allows the x-ray source, for example, to be placed adjacent to a material sample undergoing analysis or in proximity to the region to be treated for medical applications.

  8. Short Gamma-Ray Bursts from Binary Neutron Star Mergers

    E-Print Network [OSTI]

    Roland Oechslin; Thomas Janka

    2006-04-27

    We present the results from new relativistic hydrodynamic simulations of binary neutron star mergers using realistic non-zero temperature equations of state. We vary several unknown parameters in the system such as the neutron star (NS) masses, their spins and the nuclear equation of state. The results are then investigated with special focus on the post-merger torus-remnant system. Observational implications on the Gamma-ray burst (GRB) energetics are discussed and compared with recent observations.

  9. WMAPping out Neutrino Masses

    E-Print Network [OSTI]

    Aaron Pierce; Hitoshi Murayama

    2003-10-28

    Recent data from from the Wilkinson Microwave Anisotropy Probe (WMAP) place important bounds on the neutrino sector. The precise determination of the baryon number in the universe puts a strong constraint on the number of relativistic species during Big-Bang Nucleosynthesis. WMAP data, when combined with the 2dF Galaxy Redshift Survey (2dFGRS), also directly constrain the absolute mass scale of neutrinos. These results impinge upon a neutrino oscillation interpretation of the result from the Liquid Scintillator Neutrino Detector (LSND). We also note that the Heidelberg--Moscow evidence for neutrinoless double beta decay is only consistent with the WMAP+2dFGRS data for the largest values of the nuclear matrix element.

  10. X-ray spectrometry

    SciTech Connect (OSTI)

    Markowicz, A.A.; Van Grieken, R.E.

    1986-04-01

    In the period under review, i.e, through 1984 and 1985, some 600 articles on XRS (X-ray spectrometry) were published; most of these have been scanned and the most fundamental ones are discussed. All references will refer to English-language articles, unless states otherwise. Also general books have appeared on quantitative EPXMA (electron-probe X-ray microanalysis) and analytical electron microscopy (AEM) as well as an extensive review on the application of XRS to trace analysis of environmental samples. In the period under review no radically new developments have been seen in XRS. However, significant improvements have been made. Gain in intensities has been achieved by more efficient excitation, higher reflectivity of dispersing media, and better geometry. Better understanding of the physical process of photon- and electron-specimen interactions led to complex but more accurate equations for correction of various interelement effects. Extensive use of micro- and minicomputers now enables fully automatic operation, including qualitative analysis. However, sample preparation and presentation still put a limit to further progress. Although some authors find XRS in the phase of stabilization or even stagnation, further gradual developments are expected, particularly toward more dedicated equipment, advanced automation, and image analysis systems. Ways are outlined in which XRS has been improved in the 2 last years by excitation, detection, instrumental, methodological, and theoretical advances. 340 references.

  11. Constraining axion by polarized prompt emission from gamma ray bursts

    E-Print Network [OSTI]

    A. Rubbia; A. S. Sakharov

    2007-08-21

    A polarized gamma ray emission spread over a sufficiently wide energy band from a strongly magnetized astrophysical object like gamma ray bursts (GRBs) offers an opportunity to test the hypothesis of invisible axion. The axionic induced dichroism of gamma rays at different energies should cause a misalignment of the polarization plane for higher energy events relative to that one for lower energies events resulting in the loss of statistics needed to form a pattern of the polarization signal to be recognized in a detector. According to this, any evidence of polarized gamma rays coming from an object with extended magnetic field could be interpreted as a constraint on the existence of the invisible axion for a certain parameter range. Based on reports of polarized MeV emission detected in several GRBs we derive a constraint on the axion-photon coupling. This constraint $\\g_{a\\gamma\\gamma}\\le 2.2\\cdot 10^{-11} {\\rm GeV^{-1}}$ calculated for the axion mass $m_a=10^{-3} {\\rm eV}$ is competitive with the sensitivity of CAST and becomes even stronger for lower masses.

  12. Spectral Gamma-ray Signatures of Cosmological Dark Matter Annihilation

    E-Print Network [OSTI]

    Lars Bergstrom; Joakim Edsjo; Piero Ullio

    2001-12-13

    We propose a new signature for weakly interacting massive particle (WIMP) dark matter, a spectral feature in the diffuse extragalactic gamma-ray radiation. This feature, a sudden drop of the gamma-ray intensity at an energy corresponding to the WIMP mass, comes from the asymmetric distortion of the line due to WIMP annihilation into two gamma-rays caused by the cosmological redshift. Unlike other proposed searches for a line signal, this method is not very sensitive to the exact dark matter density distribution in halos and subhalos. The only requirement is that the mass distribution of substructure on small scales follows approximately the Press-Schechter law, and that smaller halos are on the average denser than large halos, which is a generic outcome of N-body simulations of Cold Dark Matter, and which has observational support. The upcoming Gamma-ray Large Area Space Telescope (GLAST) will be eminently suited to search for these spectral features. For numerical examples, we use rates computed for supersymmetric particle dark matter, where a detectable signal is possible.

  13. Light Curves of Swift Gamma Ray Bursts

    E-Print Network [OSTI]

    Paolo Cea

    2006-09-22

    Recent observations from the Swift gamma-ray burst mission indicate that a fraction of gamma ray bursts are characterized by a canonical behaviour of the X-ray afterglows. We present an effective theory which allows us to account for X-ray light curves of both (short - long) gamma ray bursts and X-ray rich flashes. We propose that gamma ray bursts originate from massive magnetic powered pulsars.

  14. Improved UTE-based attenuation correction for cranial PET-MR using dynamic magnetic field monitoring

    SciTech Connect (OSTI)

    Aitken, A. P.; Giese, D.; Tsoumpas, C.; Schleyer, P.; Kozerke, S.; Prieto, C.; Schaeffter, T., E-mail: Tobias.Schaeffter@kcl.ac.uk [Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, King's Health Partners, St. Thomas Hospital, London SE1 7EH (United Kingdom)

    2014-01-15

    Purpose: Ultrashort echo time (UTE) MRI has been proposed as a way to produce segmented attenuation maps for PET, as it provides contrast between bone, air, and soft tissue. However, UTE sequences require samples to be acquired during rapidly changing gradient fields, which makes the resulting images prone to eddy current artifacts. In this work it is demonstrated that this can lead to misclassification of tissues in segmented attenuation maps (AC maps) and that these effects can be corrected for by measuring the true k-space trajectories using a magnetic field camera. Methods: The k-space trajectories during a dual echo UTE sequence were measured using a dynamic magnetic field camera. UTE images were reconstructed using nominal trajectories and again using the measured trajectories. A numerical phantom was used to demonstrate the effect of reconstructing with incorrect trajectories. Images of an ovine leg phantom were reconstructed and segmented and the resulting attenuation maps were compared to a segmented map derived from a CT scan of the same phantom, using the Dice similarity measure. The feasibility of the proposed method was demonstrated inin vivo cranial imaging in five healthy volunteers. Simulated PET data were generated for one volunteer to show the impact of misclassifications on the PET reconstruction. Results: Images of the numerical phantom exhibited blurring and edge artifacts on the bone–tissue and air–tissue interfaces when nominal k-space trajectories were used, leading to misclassification of soft tissue as bone and misclassification of bone as air. Images of the tissue phantom and thein vivo cranial images exhibited the same artifacts. The artifacts were greatly reduced when the measured trajectories were used. For the tissue phantom, the Dice coefficient for bone in MR relative to CT was 0.616 using the nominal trajectories and 0.814 using the measured trajectories. The Dice coefficients for soft tissue were 0.933 and 0.934 for the nominal and measured cases, respectively. For air the corresponding figures were 0.991 and 0.993. Compared to an unattenuated reference image, the mean error in simulated PET uptake in the brain was 9.16% when AC maps derived from nominal trajectories was used, with errors in the SUV{sub max} for simulated lesions in the range of 7.17%–12.19%. Corresponding figures when AC maps derived from measured trajectories were used were 0.34% (mean error) and ?0.21% to +1.81% (lesions). Conclusions: Eddy current artifacts in UTE imaging can be corrected for by measuring the true k-space trajectories during a calibration scan and using them in subsequent image reconstructions. This improves the accuracy of segmented PET attenuation maps derived from UTE sequences and subsequent PET reconstruction.

  15. Experiment summary for n/y attenuation through materials (Environments 1A).

    SciTech Connect (OSTI)

    DePriest, Kendall Russell

    2006-05-01

    The Radiation Effects Sciences (RES) program is responsible for conducting Neutron Gamma Energy Transport (NuGET) code validation. In support of this task, a series of experiments were conducted in the annular core research reactor (ACRR) to investigate the modification of the incident neutron/gamma environment by aluminum (Al6061) and high-density polyethylene (HDPE) spheres with 4-in and 7-in-diameter. The experiment series described in this report addresses several NuGET validation concerns. The validation experiment series also addresses the design and execution of proper reactor testing to match the hostile radiation environments and to match the component stresses that arise from the hostile radiation environments. This report summarizes the RES Validation: n/{gamma} Attenuation through Materials, Environments 1A, experiments conducted at the ACRR in FY 2003 using ACRR Experiment Plans 933 and 949.

  16. Three years of Fermi GBM Earth Occultation Monitoring: Observations of Hard X-ray/Soft Gamma-Ray Sources

    E-Print Network [OSTI]

    Jenke, P; Case, Gary L; Cherry, Michael L; Rodi, James; Camero-Arranz, Ascension; Chaplin, Vandiver; Beklen, Elif; Finger, Mark H; Bhat, Narayana; Briggs, Michael S; Connaughto, Valerie; Greiner, Jochen; Kippen, R Marc; Meegan, Charles A; Paciesas, William S; Preece, Robert; von Kienlin, Andreas

    2013-01-01

    The Gamma ray Burst Monitor (GBM) on board Fermi Gamma-ray Space Telescope has been providing continuous data to the astronomical community since 2008 August 12. We will present the results of the analysis of the first three years of these continuous data using the Earth occultation technique to monitor a catalog of 209 sources. Although the occultation technique is in principle quite simple, in practice there are many complications including the dynamic instrument response, source confusion, and scattering in the Earth's atmosphere, which will be described. We detect 99 sources, including 40 low-mass X-ray binary/neutron star systems, 31 high-mass X-ray binary/neutron star systems, 12 black hole binaries, 12 active galaxies, 2 other sources, plus the Crab Nebula and the Sun. Nine of these sources are detected in the 100-300 keV band, including seven black-hole binaries, the active galaxy Cen A, and the Crab. The Crab and Cyg X-1 are also detected in the 300-500 keV band. GBM provides complementary data to ot...

  17. Identification of a Glycogen Synthase Kinase-3[beta] Inhibitor that Attenuates Hyperactivity in CLOCK Mutant Mice

    SciTech Connect (OSTI)

    Kozikowski, Alan P.; Gunosewoyo, Hendra; Guo, Songpo; Gaisina, Irina N.; Walter, Richard L.; Ketcherside, Ariel; McClung, Colleen A.; Mesecar, Andrew D.; Caldarone, Barbara (Psychogenics); (Purdue); (UIC); (UTSMC)

    2012-05-02

    Bipolar disorder is characterized by a cycle of mania and depression, which affects approximately 5 million people in the United States. Current treatment regimes include the so-called 'mood-stabilizing drugs', such as lithium and valproate that are relatively dated drugs with various known side effects. Glycogen synthase kinase-3{beta} (GSK-3{beta}) plays a central role in regulating circadian rhythms, and lithium is known to be a direct inhibitor of GSK-3{beta}. We designed a series of second generation benzofuran-3-yl-(indol-3-yl)maleimides containing a piperidine ring that possess IC{sub 50} values in the range of 4 to 680 nM against human GSK-3{beta}. One of these compounds exhibits reasonable kinase selectivity and promising preliminary absorption, distribution, metabolism, and excretion (ADME) data. The administration of this compound at doses of 10 to 25 mg kg{sup -1} resulted in the attenuation of hyperactivity in amphetamine/chlordiazepoxide-induced manic-like mice together with enhancement of prepulse inhibition, similar to the effects found for valproate (400 mg kg{sup -1}) and the antipsychotic haloperidol (1 mg kg{sup -1}). We also tested this compound in mice carrying a mutation in the central transcriptional activator of molecular rhythms, the CLOCK gene, and found that the same compound attenuates locomotor hyperactivity in response to novelty. This study further demonstrates the use of inhibitors of GSK-3{beta} in the treatment of manic episodes of bipolar/mood disorders, thus further validating GSK-3{beta} as a relevant therapeutic target in the identification of new therapies for bipolar patients.

  18. Moduli dispersion and attenuation in limestones in the laboratory L. Adam and M. Batzle, Center for Rock Abuse, Colorado School of Mines

    E-Print Network [OSTI]

    pressures. In the laboratory we are able to measure rock properties such as the bulk and shear modulus correlation be- tween bulk modulus dispersion and permeability. We also measure dif- ferent modes of attenuation and find that the attenuation in our fully- saturated samples is mostly due to bulk

  19. The Subatomic Particle Mass Spectrum

    E-Print Network [OSTI]

    R. L. Oldershaw

    2010-09-20

    Representative members of the subatomic particle mass spectrum in the 100 MeV to 7,000 MeV range are retrodicted to a first approximation using the Kerr solution of General Relativity. The particle masses appear to form a restricted set of quantized values of a Kerr-based angular momentum-mass relation: m = (sqrt n)(M), where values of n are a set of discrete integers and M is a revised Planck mass. A fractal paradigm manifesting global discrete self-similarity is critical to a proper determination of M, which differs from the conventional Planck mass by roughly 19 orders of magnitude. This exceedingly simple and generic mass equation retrodicts the masses of a representative set of 27 well-known particles with an average relative error of 1.6%. A more rigorous mass formula, which includes the total spin angular momentum rule of Quantum Mechanics, the canonical spin values of the particles, and the dimensionless rotational parameter of the Kerr angular momentum-mass relation, is able to retrodict the masses of the 8 dominant baryons in the 900 MeV to 1700 MeV range at the 99.7% level, on average.

  20. Cosmic Ray Protons Illuminate Dark Matter Axions

    E-Print Network [OSTI]

    H. Tam; Q. Yang

    2011-08-16

    Cosmic ray protons propagating in a spatially-homogeneous but time-dependent field of axions or axion-like particles (ALPs) emit photons in a way that is reminiscent of Cherenkov radiation by charged particles in a preferred background. We compute the emission rate and energy spectrum of the photons, and discuss the possibility of their detection using the Square Kilometre Array which is currently under construction. In the case of a non-detection, constraints can be placed on the parameter space of ALPs whose mass lie between $10^{-7}$eV and $10^{-5}$ eV under the assumption that they are the primary constituent of dark matter.

  1. Single well field injection test of humate to enhance attenuation of uranium and other radionuclides in an acidic plume

    SciTech Connect (OSTI)

    Denham, M.

    2014-09-30

    This report documents the impact of the injected humate on targeted contaminants over a period of 4 months and suggests it is a viable attenuation-based remedy for uranium, potentially for I-129, but not for Sr-90. Future activities will focus on issues pertinent to scaling the technology to full deployment.

  2. Ultrasound attenuation measurements in the B-like phase of superfluid 3He embedded in 98% porosity aerogel have been

    E-Print Network [OSTI]

    aerogel have been performed at four frequencies between 3.6 and 11.3 MHz. At all of the pressures studied. Considering the unique aspects of aerogel originating from its structure, correlation and finite size Ultrasound Attenuation in Superfluid 3He in Aerogel* B.H. Moon, N. Masuhara, P. Bhupathi, M. Gonzalez, M

  3. Symptom Attenuation by a Satellite RNA in Vivo Is Dependent on Reduced Levels of Virus Coat Protein

    E-Print Network [OSTI]

    Simon, Anne

    Symptom Attenuation by a Satellite RNA in Vivo Is Dependent on Reduced Levels of Virus Coat Protein; returned to author for revision April 14, 1999; accepted April 26, 1999 Many plant RNA viruses provide the symptoms of the associated helper virus. Sat-RNA C, a virulent sat-RNA associated with turnip crinkle virus

  4. Frequency dependent elastic properties and attenuation in heavy-oil sands: comparison between mea-sured and modeled data

    E-Print Network [OSTI]

    Frequency dependent elastic properties and attenuation in heavy-oil sands: comparison between mea) properties of heavy-oil sands over a range of frequencies (2 - 2000Hz) covering the seismic bandwidth and at ultrasonic frequencies (0.8MHz). The measurements were carried on heavy-oil sand sample from Asphalt Ridge

  5. Modeling the natural attenuation of benzene in groundwater impacted by ethanol-blended fuels: Effect of ethanol content

    E-Print Network [OSTI]

    Alvarez, Pedro J.

    Modeling the natural attenuation of benzene in groundwater impacted by ethanol-blended fuels: Effect of ethanol content on the lifespan and maximum length of benzene plumes Diego E. Gomez1 and Pedro 10 March 2009. [1] A numerical model was used to evaluate how the concentration of ethanol

  6. The first peak ground motion attenuation relationships for North of Vietnam Le Minh Nguyen a,d

    E-Print Network [OSTI]

    Wu, Yih-Min

    . Ground motion data are collected by a portable broadband seismic network in northern Vietnam as a part with the station corrections for ML and imply the qualification of the resulting attenuation relationships. Ó 2011 by the Paci- fic belt and Mediterranean­Himalaya seismic belt on its eastern, western and southern sides

  7. MASS STORAGE SYSTEMS AND LARGE RESEARCH LIBRARIES

    E-Print Network [OSTI]

    Baker, James A.

    2013-01-01

    Symposium on Mass Storage Systems, Denver, CO, April15-17, 1980 MASS STORAGE SYSTEMS AND LARGE RESEARCHSymposium on Mass Storage Systems, Denver, Colorado, April

  8. Ultrahigh Energy Cosmic Rays: Facts, Myths, and Legends

    E-Print Network [OSTI]

    Luis Alfredo Anchordoqui

    2011-04-04

    This is a written version of a series of lectures aimed at graduate students in astrophysics/particle theory/particle experiment. In the first part, we explain the important progress made in recent years towards understanding the experimental data on cosmic rays with energies > 10^8 GeV. We begin with a brief survey of the available data, including a description of the energy spectrum, mass composition, and arrival directions. At this point we also give a short overview of experimental techniques. After that, we introduce the fundamentals of acceleration and propagation in order to discuss the conjectured nearby cosmic ray sources, and emphasize some of the prospects for a new (multi-particle) astronomy. Next, we survey the state of the art regarding the ultrahigh energy cosmic neutrinos which should be produced in association with the observed cosmic rays. In the second part, we summarize the phenomenology of cosmic ray air showers. We explain the hadronic interaction models used to extrapolate results from collider data to ultrahigh energies, and describe the prospects for insights into forward physics at the Large Hadron Collider (LHC). We also explain the main electromagnetic processes that govern the longitudinal shower evolution. Armed with these two principal shower ingredients and motivation from the underlying physics, we describe the different methods proposed to distinguish primary species. In the last part, we outline how ultrahigh energy cosmic ray interactions can be used to probe new physics beyond the electroweak scale.

  9. The Origin of Cosmic Rays

    ScienceCinema (OSTI)

    Blasi, Pasquale [INAF/Arcetri-Italy and Fermilab, Italy

    2010-01-08

    Cosmic Rays reach the Earth from space with energies of up to more than 1020 eV, carrying information on the most powerful particle accelerators that Nature has been able to assemble. Understanding where and how cosmic rays originate has required almost one century of investigations, and, although the last word is not written yet, recent observations and theory seem now to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the ?end? of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform ?cosmic ray astronomy?, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

  10. Mini ion trap mass spectrometer

    DOE Patents [OSTI]

    Dietrich, Daniel D. (Livermore, CA); Keville, Robert F. (Valley Springs, CA)

    1995-01-01

    An ion trap which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10.sup.9 and commercial mass spectrometers requiring 10.sup.4 ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products.

  11. Mini ion trap mass spectrometer

    DOE Patents [OSTI]

    Dietrich, D.D.; Keville, R.F.

    1995-09-19

    An ion trap is described which operates in the regime between research ion traps which can detect ions with a mass resolution of better than 1:10{sup 9} and commercial mass spectrometers requiring 10{sup 4} ions with resolutions of a few hundred. The power consumption is kept to a minimum by the use of permanent magnets and a novel electron gun design. By Fourier analyzing the ion cyclotron resonance signals induced in the trap electrodes, a complete mass spectra in a single combined structure can be detected. An attribute of the ion trap mass spectrometer is that overall system size is drastically reduced due to combining a unique electron source and mass analyzer/detector in a single device. This enables portable low power mass spectrometers for the detection of environmental pollutants or illicit substances, as well as sensors for on board diagnostics to monitor engine performance or for active feedback in any process involving exhausting waste products. 10 figs.

  12. Electron Effective Mass in Graphene

    E-Print Network [OSTI]

    Viktor Ariel; Amir Natan

    2012-08-12

    The particle effective mass in graphene is a challenging concept because the commonly used theoretical expression is mathematically divergent. In this paper, we use basic principles to present a simple theoretical expression for the effective mass that is suitable for both parabolic and non-parabolic isotropic materials. We demonstrate that this definition is consistent with the definition of the cyclotron effective mass, which is one of the common methods for effective mass measurement in solid state materials. We apply the proposed theoretical definition to graphene and demonstrate linear dependence of the effective mass on momentum, as confirmed by experimental cyclotron resonance measurements. Therefore, the proposed definition of the effective mass can be used for non-parabolic materials such as graphene.

  13. Ray2008.ppt

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMassR&D100 Winners * Impacts on GlobalRachel2RateCaseElements Sign In About |

  14. X-ray Emission from the Taffy (VV254) Galaxies and Bridge

    E-Print Network [OSTI]

    Appleton, Philip; Bitsakis, Theodoros; Wang, Junfeng; Peterson, Bradley; Lisenfeld, Ute; Alatalo, Katherine; Guillard, Pierre; Boulanger, Francois; Cluver, Michelle; Gao, Yu; Helou, George; Ogle, Patrick; Struck, Curtis

    2015-01-01

    We present the first X-ray observations of the Taffy galaxies (UGC 12914/5) with the Chandra observatory, and detect soft X-ray emission in the region of the gas-rich, radio-continuum-emitting Taffy bridge. The results are compared to Herschel observations of dust and diffuse [CII] line-emitting gas. The diffuse component of the Taffy bridge has an X-ray luminosity of L(X) (0.5-8keV) =5.4 x 10^39 erg s^-1, which accounts for 19% of the luminosity of the sum for the two galaxies. The total mass in hot gas is (0.8--1.3) x 10^8 M_sun, which is approximately 1% of the total (HI~+~H2) gas mass in the bridge, and ~11% of the mass of warm molecular hydrogen discovered by Spitzer. The soft X-ray and dense CO-emitting gas in the bridge have offset distributions, with the X-rays peaking along the north-western side of the bridge in the region where stronger far-IR dust and diffuse [CII] gas is observed by Herschel. We detect nine Ultra Luminous X-ray sources (ULXs) in the system, the brightest of which is found in the ...

  15. X-ray shearing interferometer

    DOE Patents [OSTI]

    Koch, Jeffrey A. (Livermore, CA)

    2003-07-08

    An x-ray interferometer for analyzing high density plasmas and optically opaque materials includes a point-like x-ray source for providing a broadband x-ray source. The x-rays are directed through a target material and then are reflected by a high-quality ellipsoidally-bent imaging crystal to a diffraction grating disposed at 1.times. magnification. A spherically-bent imaging crystal is employed when the x-rays that are incident on the crystal surface are normal to that surface. The diffraction grating produces multiple beams which interfere with one another to produce an interference pattern which contains information about the target. A detector is disposed at the position of the image of the target produced by the interfering beams.

  16. Water destruction by X-rays in young stellar objects

    E-Print Network [OSTI]

    P. Stauber; J. K. Jorgensen; E. F. van Dishoeck; S. D. Doty; A. O. Benz

    2006-02-06

    We study the H2O chemistry in star-forming environments under the influence of a central X-ray source and a central far ultraviolet (FUV) radiation field. The gas-phase water chemistry is modeled as a function of time, hydrogen density and X-ray flux. To cover a wide range of physical environments, densities between n_H = 10^4-10^9 cm^-3 and temperatures between T = 10-1000 K are studied. Three different regimes are found: For T water abundance is of order 10^-7-10^-6 and can be somewhat enhanced or reduced due to X-rays, depending on time and density. For 100 K 10^-3 ergs s-1 cm^-2 (t = 10^4 yrs) and for F_X > 10^-4 ergs s^-1 cm^-2 (t = 10^5 yrs). At higher temperatures (T > 250 K) and hydrogen densities, water can persist with x(H2O) ~ 10^-4 even for high X-ray fluxes. The X-ray and FUV models are applied to envelopes around low-mass Class 0 and I young stellar objects (YSOs). Water is destroyed in both Class 0 and I envelopes on relatively short timescales (t ~ 5000 yrs) for realistic X-ray fluxes, although the effect is less prominent in Class 0 envelopes due to the higher X-ray absorbing densities there. FUV photons from the central source are not effective in destroying water. The average water abundance in Class I sources for L_X > 10^27 ergs s^-1 is predicted to be x(H2O) < 10^-6.

  17. Cosmic ray spectrum by energy scattered by EAS particles in the atmosphere and galactic model

    E-Print Network [OSTI]

    S. P. Knurenko; A. A. Ivanov; A. V. Sabourov

    2007-11-16

    The differential energy spectrum of cosmic rays from Cherenkov radiation measurements in EAS in the energy range of 10^15-10^20eV has been compared with an anomalous diffusion model for the particles in interstellar space having fractal properties (Lagutin et al, 2001). The close association between experimental data and calculated "all particle" spectra in form at E(0) (10^15-10^18)eV is found. In this case, the average mass composition of cosmic rays calculated by five components does not contradict the average mass composition from experimental data which was obtained by several of EAS characteristics in that energy region.

  18. Quarkonia and the Pole Mass

    E-Print Network [OSTI]

    A. H. Hoang; M. C. Smith; T. Stelzer; S. Willenbrock

    1999-04-07

    The pole mass of a heavy quark is ambiguous by an amount of order $\\Lambda_{QCD}$. We show that the heavy-quark potential, $V(r)$, is similarly ambiguous, but that the total static energy, $2M_{pole}+V(r)$, is unambiguous when expressed in terms of a short-distance mass. This implies that the extraction of a short-distance mass from the quarkonium spectrum is free of an ambiguity of order $\\Lambda_{QCD}$, in contrast with the pole mass.

  19. Relativistic mass and modern physics

    E-Print Network [OSTI]

    Z. K. Silagadze

    2014-12-15

    At first sight, arguments for and against the notion of relativistic mass look like a notorious intra-Lilliputian quarrel between Big-Endians (those who broke their eggs at the larger end) and Little-Endians. However, upon closer inspection we discover that the relativistic mass notion is alien to the spirit of modern physics to a much greater extent than it seems. To demonstrate an abyss between the modern approach and archaic notions, in this paper we explore how the concept of mass is introduced in modern physics. This modern approach reveals a deep cohomological origin of mass.

  20. High efficiency of soft X-ray radiation reprocessing in supersoft X-ray sources due to multiple scattering

    E-Print Network [OSTI]

    V. Suleimanov; F. Meyer; E. Meyer-Hofmeister

    2003-02-19

    Detailed analysis of the lightcurve of CAL 87 clearly has shown that the high optical luminosity comes from the accretion disc rim and can only be explained by a severe thickening of the disc rim near the location where the accretion stream impinges. This area is irradiated by the X-rays where it faces the white dwarf. Only if the reprocessing rate of X-rays to optical light is high a luminosity as high as observed can be understood. But a recent detailed study of the soft X-ray radiation reprocessing in supersoft X-ray sources has shown that the efficiency is not high enough. We here propose a solution for this problem. As already discussed in the earlier lightcurve analysis the impact of the accretion stream at the outer disc rim produces a ``spray'', consisting of a large number of individual gas blobs imbedded in a surrounding corona. For the high mass flow rate this constitutes an optically thick vertically extended screen at the rim of the accretion disc. We analyse the optical properties of this irradiated spray and find that the multiple scattering between these gas blobs leads to an effective reprocessing of soft X-rays to optical light as required by the observations.

  1. Static-light meson masses from twisted mass lattice QCD

    E-Print Network [OSTI]

    ETM Collaboration; Karl Jansen; Chris Michael; Andrea Shindler; Marc Wagner

    2008-08-15

    We compute the static-light meson spectrum using two-flavor Wilson twisted mass lattice QCD. We have considered five different values for the light quark mass corresponding to 300 MeV < m_PS < 600 MeV. We have extrapolated our results, to make predictions regarding the spectrum of B and B_s mesons.

  2. Swift Pointing and the Association Between Gamma-Ray Bursts and Gravitational-Wave Bursts

    E-Print Network [OSTI]

    Lee Samuel Finn; Badri Krishnan; Patrick J. Sutton

    2003-04-11

    The currently accepted model for gamma-ray burst phenomena involves the violent formation of a rapidly rotating solar mass black hole. Gravitational waves should be associated with the black-hole formation, and their detection would permit this model to be tested, the black hole progenitor (e.g., coalescing binary or collapsing stellar core) identified, and the origin of the gamma rays (within the expanding relativistic fireball or at the point of impact on the interstellar medium) located. Even upper limits on the gravitational-wave strength associated with gamma-ray bursts could constrain the gamma-ray burst model. To do any of these requires joint observations of gamma-ray burst events with gravitational and gamma-ray detectors. Here we examine how the quality of an upper limit on the gravitational-wave strength associated with gamma-ray burst observations depends on the relative orientation of the gamma-ray-burst and gravitational-wave detectors, and apply our results to the particular case of the Swift Burst-Alert Telescope (BAT) and the LIGO gravitational-wave detectors. A result of this investigation is a science-based ``figure of merit'' that can be used, together with other mission constraints, to optimize the pointing of the Swift telescope for the detection of gravitational waves associated with gamma-ray bursts.

  3. Radio, Sub-mm, and X-ray Studies of Gamma-Ray Burst Host Galaxies

    E-Print Network [OSTI]

    E. Berger

    2001-12-29

    The study of gamma-ray burst (GRB) host galaxies in the radio, sub-mm, and X-ray wavelength regimes began only recently, in contrast to optical studies. This is mainly due to the long timescale on which the radio afterglow emission decays, and to the intrinsic faintness of radio emission from star-forming galaxies at z~1, as well as source confusion in sub-mm observations; X-ray observations of GRB hosts have simply not been attempted yet. Despite these difficulties, we have recently made the first detections of radio and sub-mm emission from the host galaxies of GRB980703 and GRB010222, respectively, using the VLA and the SCUBA instrument on JCMT. In both cases we find that the inferred star formation rates (~500 solar masses per year) and bolometric luminosities (~few 10^12 solar luminosities) indicate that these galaxies are possibly analogous to the local population of Ultra-Luminous Infrared Galaxies (ULIRGs) undergoing a starburst. However, there is a modest probability that the observed emission is due to AGN activity rather than star formation, thus requiring observations with Chandra or XMM. The sample of GRB hosts offers a number of unique advantages to the broader question of the evolution of galaxies and star formation from high redshift to the present time since: (i) GRBs trace massive stars, (ii) are detectable to high redshifts, and (iii) have immense dust penetrating power. Therefore, radio/sub-mm/X-ray observations of GRB hosts can potentially provide crucial information both on the nature of the GRB host galaxies, and on the history of star formation.

  4. Studying Gamma Ray Bursts from a

    E-Print Network [OSTI]

    ?umer, Slobodan

    Studying Gamma Ray Bursts from a new perspective! {... Unraveling some mysteries and adding new Radio Op0cal X-ray Short ( energy -ray photons... ... accompained by a considerable long las0ng emission

  5. The X-ray Lightcurve of the Supermassive star eta Carinae, 1996--2014

    E-Print Network [OSTI]

    Corcoran, M F; Liburd, J K; Morris, D; Gull, T R; Madura, T I; Teodoro, M; Moffat, A F J; Richardson, N D; Russell, C M P; Pollock, A M T; Owocki, S P

    2015-01-01

    Eta Carinae is the nearest example of a supermassive, superluminous, unstable star. Mass loss from the system is critical in shaping its circumstellar medium and in determining its ultimate fate. Eta Car currently loses mass via a dense, slow stellar wind and possesses one of the largest mass loss rates known. It is prone to episodes of extreme mass ejection via eruptions from some as-yet unspecified cause; the best examples of this are the large-scale eruptions which occurred in 19th century. Eta Car is a colliding wind binary in which strong variations in X-ray emission and in other wavebands are driven by the violent collision of the wind of eta Car-A and the fast, less dense wind of an otherwise hidden companion star. X-ray variations are the simplest diagnostic we have to study the wind-wind collision and allow us to measure the state of the stellar mass loss from both stars. We present the X-ray lightcurve over the last 20 years from ROSAT observations and monitoring with the Rossi X-ray Timing Explorer...

  6. GIANT X-RAY BUMP IN GRB 121027A: EVIDENCE FOR FALL-BACK DISK ACCRETION

    SciTech Connect (OSTI)

    Wu Xuefeng [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Hou Shujin [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China); Lei Weihua, E-mail: xfwu@pmo.ac.cn, E-mail: leiwh@hust.edu.cn [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2013-04-20

    A particularly interesting discovery in observations of GRB 121027A is that of a giant X-ray bump detected by the Swift/X-Ray Telescope. The X-ray afterglow re-brightens sharply at {approx}10{sup 3} s after the trigger by more than two orders of magnitude in less than 200 s. This X-ray bump lasts for more than 10{sup 4} s. It is quite different from typical X-ray flares. In this Letter we propose a fall-back accretion model to interpret this X-ray bump within the context of the collapse of a massive star for a long-duration gamma-ray burst. The required fall-back radius of {approx}3.5 Multiplication-Sign 10{sup 10} cm and mass of {approx}0.9-2.6 M{sub Sun} imply that a significant part of the helium envelope should survive through the mass loss during the last stage of the massive progenitor of GRB 121027A.

  7. Center for X-Ray Optics, 1992

    SciTech Connect (OSTI)

    Not Available

    1993-08-01

    This report discusses the following topics: Center for X-Ray Optics; Soft X-Ray Imaging wit Zone Plate Lenses; Biological X-Ray microscopy; Extreme Ultraviolet Lithography for Nanoelectronic Pattern Transfer; Multilayer Reflective Optics; EUV/Soft X-ray Reflectometer; Photoemission Microscopy with Reflective Optics; Spectroscopy with Soft X-Rays; Hard X-Ray Microprobe; Coronary Angiography; and Atomic Scattering Factors.

  8. On the Origin of Ultra High Energy Cosmic Rays II

    SciTech Connect (OSTI)

    Fowler, T K; Colgate, S; Li, H; Bulmer, R H; Pino, J

    2011-03-08

    We show that accretion disks around Active Galactic Nuclei (AGNs) could account for the enormous power in observed ultra high energy cosmic rays {approx}10{sup 20} eV (UHEs). In our model, cosmic rays are produced by quasi-steady acceleration of ions in magnetic structures previously proposed to explain jets around Active Galactic Nuclei with supermassive black holes. Steady acceleration requires that an AGN accretion disk act as a dynamo, which we show to follow from a modified Standard Model in which the magnetic torque of the dynamo replaces viscosity as the dominant mechanism accounting for angular momentum conservation during accretion. A black hole of mass M{sub BH} produces a steady dynamo voltage V {proportional_to} {radical}M{sub BH} giving V {approx} 10{sup 20} volts for M{sub BH} {approx} 10{sup 8} solar masses. The voltage V reappears as an inductive electric field at the advancing nose of a dynamo-driven jet, where plasma instability inherent in collisionless runaway acceleration allows ions to be steadily accelerated to energies {approx} V, finally ejected as cosmic rays. Transient events can produce much higher energies. The predicted disk radiation is similar to the Standard Model. Unique predictions concern the remarkable collimation of jets and emissions from the jet/radiolobe structure. Given MBH and the accretion rate, the model makes 7 predictions roughly consistent with data: (1) the jet length; (2) the jet radius; (3) the steady-state cosmic ray energy spectrum; (4) the maximum energy in this spectrum; (5) the UHE cosmic ray intensity on Earth; (6) electron synchrotron wavelengths; and (7) the power in synchrotron radiation. These qualitative successes motivate new computer simulations, experiments and data analysis to provide a quantitative verification of the model.

  9. Gravity and the Fermion Mass

    E-Print Network [OSTI]

    Kenneth Dalton

    2010-06-11

    It is shown that gravity generates mass for the fermion. It does so by coupling directly with the spinor field. The coupling term is invariant with respect to the electroweak gauge group $ U(1) \\otimes SU(2)_L. $ It replaces the fermion mass term $ m\\bar{\\psi} \\psi $.

  10. Fermion Masses without Yukawa Couplings

    E-Print Network [OSTI]

    Francesca Borzumati; Glennys Farrar; Nir Polonsky; Scott Thomas

    1998-05-13

    Radiatively generated fermion masses without tree level Yukawa couplings are re-analyzed within supersymmetric models. Special emphasis is given to the possible appearance of color and charge breaking vacua. Several scenarios in which the radiative mechanism can be accomodated for the first, second, and third generation fermion masses are presented. Some of these require a low scale of supersymmetry breaking.

  11. SciTech Connect: "gamma ray bursts"

    Office of Scientific and Technical Information (OSTI)

    gamma ray bursts" Find + Advanced Search Term Search Semantic Search Advanced Search All Fields: "gamma ray bursts" Semantic Semantic Term Title: Full Text: Bibliographic Data:...

  12. Detectors of Cosmic Rays, Gamma Rays, and Neutrinos

    SciTech Connect (OSTI)

    Altamirano, A.; Navarra, G.

    2009-04-30

    We summarize the main features, properties and performances of the typical detectors in use in Cosmic Ray Physics. A brief historical and general introduction will focus on the main classes and requirements of such detectors.

  13. Fiber fed x-ray/gamma ray imaging apparatus

    DOE Patents [OSTI]

    Hailey, Charles J. (San Francisco, CA); Ziock, Klaus-Peter (Livermore, CA)

    1992-01-01

    X-ray/gamma ray imaging apparatus is disclosed for detecting the position, energy, and intensity of x-ray/gamma ray radiation comprising scintillation means disposed in the path of such radiation and capable of generating photons in response to such radiation; first photodetection means optically bonded to the scintillation means and capable of generating an electrical signal indicative of the intensity, and energy of the radiation detected by the scintillation means; second photodetection means capable of generating an electrical signal indicative of the position of the radiation in the radiation pattern; and means for optically coupling the scintillation means to the second photodetection means. The photodetection means are electrically connected to control and storage means which may also be used to screen out noise by rejecting a signal from one photodetection means not synchronized to a signal from the other photodetection means; and also to screen out signals from scattered radiation.

  14. Ultrahigh Energy Cosmic Rays Detection

    E-Print Network [OSTI]

    Carla Aramo

    2005-09-06

    The paper describes methods used for the detection of cosmic rays with energies above 10^18 eV (UHECR, UltraHigh Energy Cosmic Rays). It had been anticipated there would be a cutoff in the energy spectrum of primary cosmic rays around 3 10^19 eV induced by their interaction with the 2.7 K primordial photons. This has become known as the GZK cutoff. However, several showers have been detected with estimated primary energy exceeding this limit.

  15. X-ray fluorescence mapping

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorkingLos Alamos verifies largest single goldWindX-RayX-Ray ScienceX-Ray

  16. Weighted simultaneous algebraic reconstruction technique for tomosynthesis imaging of objects with high-attenuation features

    SciTech Connect (OSTI)

    Levakhina, Y. M.; Mueller, J.; Buzug, T. M.; Duschka, R. L.; Vogt, F.; Barkhausen, J.

    2013-03-15

    Purpose: This paper introduces a nonlinear weighting scheme into the backprojection operation within the simultaneous algebraic reconstruction technique (SART). It is designed for tomosynthesis imaging of objects with high-attenuation features in order to reduce limited angle artifacts. Methods: The algorithm estimates which projections potentially produce artifacts in a voxel. The contribution of those projections into the updating term is reduced. In order to identify those projections automatically, a four-dimensional backprojected space representation is used. Weighting coefficients are calculated based on a dissimilarity measure, evaluated in this space. For each combination of an angular view direction and a voxel position an individual weighting coefficient for the updating term is calculated. Results: The feasibility of the proposed approach is shown based on reconstructions of the following real three-dimensional tomosynthesis datasets: a mammography quality phantom, an apple with metal needles, a dried finger bone in water, and a human hand. Datasets have been acquired with a Siemens Mammomat Inspiration tomosynthesis device and reconstructed using SART with and without suggested weighting. Out-of-focus artifacts are described using line profiles and measured using standard deviation (STD) in the plane and below the plane which contains artifact-causing features. Artifacts distribution in axial direction is measured using an artifact spread function (ASF). The volumes reconstructed with the weighting scheme demonstrate the reduction of out-of-focus artifacts, lower STD (meaning reduction of artifacts), and narrower ASF compared to nonweighted SART reconstruction. It is achieved successfully for different kinds of structures: point-like structures such as phantom features, long structures such as metal needles, and fine structures such as trabecular bone structures. Conclusions: Results indicate the feasibility of the proposed algorithm to reduce typical tomosynthesis artifacts produced by high-attenuation features. The proposed algorithm assigns weighting coefficients automatically and no segmentation or tissue-classification steps are required. The algorithm can be included into various iterative reconstruction algorithms with an additive updating strategy. It can also be extended to computed tomography case with the complete set of angular data.

  17. Quinoline and derivatives at a tar oil contaminated site: hydroxylated products as indicator for natural attenuation?

    SciTech Connect (OSTI)

    Anne-Kirsten Reineke; Thomas Goeen; Alfred Preiss; Juliane Hollender [RWTH Aachen, Aachen (Germany). Institute of Hygiene and Environmental Medicine

    2007-08-01

    LC-MS-MS analysis of groundwater of a tar oil contaminated site (a former coal mine and coking plant in Castrop-Rauxel, Germany) showed the occurrence of the N-heterocycles quinoline and isoquinoline as well as their hydroxylated and hydrogenated metabolites. The concentrations of the hydroxylated compounds, 2(1H)-quinolinone and 1(2H)-isoquinolinone, were significantly higher than those of the nonsubstituted parent compounds. Therefore, exclusive quantification of the parent compounds leads to an underestimation of the amount of N-heterocycles present in the groundwater. Microbial degradation experiments of quinoline and isoquinoline with aquifer material of the site as inocculum showed the formation of hydroxylated and hydrogenated products under sulfate-reducing conditions, the prevailing conditions in the field. However, since analyses of seven tar products showed that these compounds are also primary constituents, their detection in groundwater is found to be a nonsufficient indicator for the occurrence of biological natural attenuation processes. Instead, the ratio of hydroxylated to parent compound (R{sub metabolite}) is proposed as a useful indicator. We found that 65-83% of all groundwater samples showed R{sub metabolite} for 2(1H)-quinolinone, 1(2H)-isoquinolinone, 3,4-dihydro-2(1H)-quinolinone, and 3,4-dihydro-1(2H)-isoquinolinone, which was higher than the highest ratio found in tar products. With respect to the observed partition coefficient between tar oil and water of 3.5 for quinoline and isoquinoline and 0.3 for 2(1H)-quinolinone and 1(2H)-isoquinolinone, the ratio in groundwater would be approximately 10 times higher than the ratio in tar oil. When paying attention to these two parameters, 19-31% of groundwater samples exceed the highest tar oil ratio. This indicates that biological processes take place in the aquifer of the site and R{sub metabolite} is an applicable indicator for natural attenuation. 42 refs., 6 figs., 2 tabs.

  18. X-ray Spectral Properties of Gamma-Ray Bursts

    E-Print Network [OSTI]

    T. E. Strohmayer; E. E. Fenimore; T. Murakami; A. Yoshida

    1997-12-18

    We summarize the spectral characteristics of a sample of 22 bright gamma-ray bursts detected with the gamma-ray burst sensors aboard the satellite Ginga. This instrument employed a proportional and scintillation counter to provide sensitivity to photons in the 2 - 400 keV range, providing a unique opportunity to characterize the largely unexplored X-ray properties of gamma-ray bursts. The photon spectra of the Ginga bursts are well described by a low energy slope, a bend energy, and a high energy slope. In the energy range where they can be compared, this result is consistent with burst spectral analyses obtained from the BATSE experiment aboard the Compton Observatory. However, below 20 keV we find evidence for a positive spectral number index in approximately 40% of our burst sample, with some evidence for a strong rolloff at lower energies in a few events. There is a correlation (Pearson's r = -0.62) between the low energy slope and the bend energy. We find that the distribution of spectral bend energies extends below 10 keV. The observed ratio of energy emitted in the X-rays relative to the gamma-rays can be much larger than a few percent and, in fact, is sometimes larger than unity. The average for our sample is 24%.

  19. High-rate x-ray spectroscopy in mammography with a CdTe detector: A digital pulse processing approach

    SciTech Connect (OSTI)

    Abbene, L.; Gerardi, G.; Principato, F.; Del Sordo, S.; Ienzi, R.; Raso, G. [Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy) and INAF/IASF Palermo, Via Ugo La Malfa 153, 90146 Palermo (Italy); Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy); INAF/IASF Palermo, Via Ugo La Malfa 153, 90146 Palermo (Italy); Istituto di Radiologia, Policlinico, 90100 Palermo (Italy); Dipartimento di Fisica e Tecnologie Relative, Universita di Palermo, Viale delle Scienze, Edificio 18, Palermo 90128 (Italy)

    2010-12-15

    Purpose:Direct measurement of mammographic x-ray spectra under clinical conditions is a difficult task due to the high fluence rate of the x-ray beams as well as the limits in the development of high resolution detection systems in a high counting rate environment. In this work we present a detection system, based on a CdTe detector and an innovative digital pulse processing (DPP) system, for high-rate x-ray spectroscopy in mammography. Methods: The DPP system performs a digital pile-up inspection and a digital pulse height analysis of the detector signals, digitized through a 14-bit, 100 MHz digitizer, for x-ray spectroscopy even at high photon counting rates. We investigated on the response of the digital detection system both at low (150 cps) and at high photon counting rates (up to 500 kcps) by using monoenergetic x-ray sources and a nonclinical molybdenum anode x-ray tube. Clinical molybdenum x-ray spectrum measurements were also performed by using a pinhole collimator and a custom alignment device. Results: The detection system shows excellent performance up to 512 kcps with an energy resolution of 4.08% FWHM at 22.1 keV. Despite the high photon counting rate (up to 453 kcps), the molybdenum x-ray spectra, measured under clinical conditions, are characterized by a low number of pile-up events. The agreement between the attenuation curves and the half value layer values, obtained from the measured spectra, simulated spectra, and from the exposure values directly measured with an ionization chamber, also shows the accuracy of the measurements. Conclusions: These results make the proposed detection system a very attractive tool for both laboratory research and advanced quality controls in mammography.

  20. On detecting oscillations of gamma rays into axion-like particles in turbulent and coherent magnetic fields

    E-Print Network [OSTI]

    Manuel Meyer; Daniele Montanino; Jan Conrad

    2014-09-04

    Background radiation fields pervade the Universe, and above a certain energy any $\\gamma$-ray flux emitted by an extragalactic source should be attenuated due to $e^+e^-$ pair production. The opacity could be alleviated if photons oscillated into hypothetical axion-like particles (ALPs) in ambient magnetic fields, leading to a $\\gamma$-ray excess especially at high optical depths that could be detected with imaging air Cherenkov telescopes (IACTs). Here, we introduce a method to search for such a signal in $\\gamma$-ray data and to estimate sensitivities for future observations. Different magnetic fields close to the $\\gamma$-ray source are taken into account in which photons can convert into ALPs that then propagate unimpeded over cosmological distances until they re-convert in the magnetic field of the Milky Way. Specifically, we consider the coherent field at parsec scales in a blazar jet as well as the turbulent field inside a galaxy cluster. For the latter, we explicitly derive the transversal components of a magnetic field with gaussian turbulence which are responsible for the photon-ALP mixing. To illustrate the method, we apply it to a mock IACT array with characteristics similar to the Cherenkov Telescope Array and investigate the dependence of the sensitivity to detect a $\\gamma$-ray excess on the magnetic-field parameters.

  1. Modelling gamma-ray-axion-like particle oscillations in turbulent magnetic fields: relevance for observations with Cherenkov telescopes

    E-Print Network [OSTI]

    Manuel Meyer

    2014-12-08

    Axion-like particles (ALPs) are a common prediction of certain theories beyond the Standard Model and couple to photons in the presence of external magnetic fields. As a consequence, photon-ALP conversions could lead to an enhancement of the flux of extragalactic gamma-ray sources that is otherwise attenuated due to the interactions with background radiation fields. The magnetic fields traversed by the gamma rays are often turbulent and frequently modelled with a simple domain-like structure. Given a maximum mixing between photons and ALPs, we show that in such models realisations of the fields exist for which the photon-ALP oscillation probability vanishes. This behaviour does not occur in more sophisticated magnetic-field models.

  2. The evolution of planetary nebulae. V. The diffuse X-ray emission

    E-Print Network [OSTI]

    M. Steffen; D. Schoenberner; A. Warmuth

    2008-09-05

    Observations with space-borne X-ray telescopes revealed the existence of soft, diffuse X-ray emission from the inner regions of planetary nebulae. Although the existing images support the idea that this emission arises from the hot shocked central-star wind which fills the inner cavity of a planetary nebula, existing models have difficulties to explain the observations consistently. We investigate how the inclusion of thermal conduction changes the physical parameters of the hot shocked wind gas and the amount of X-ray emission predicted by time-dependent hydrodynamical models of planetary nebulae with central stars of normal, hydrogen-rich surface composition. The radiation hydrodynamical models show that heat conduction leads to lower temperatures and higher densities within a bubble and brings the physical properties of the X-ray emitting domain into close agreement with the values derived from observations. Depending on the central-star mass and the evolutionary phase, our models predict X-ray [0.45--2.5 keV] luminosities between $10^{-8}$ and $10^{-4}$ of the stellar bolometric luminosities, in good agreement with the observations. Less than 1% of the wind power is radiated away in this X-ray band. Although temperature, density, and also the mass of the hot bubble is significantly altered by heat conduction, the dynamics of the whole system remains practically the same. Heat conduction allows the construction of nebular models which predict the correct amount of X-ray emission and at the same time are fully consistent with the observed mass-loss rate and wind speed. Thermal conduction must be considered as a viable physical process for explaining the diffuse X-ray emission from planetary nebulae with closed inner cavities. Magnetic fields must then be absent or extremely weak.

  3. Cosmic Rays and Global Warming

    E-Print Network [OSTI]

    T. Sloan; A W Wolfendale

    2007-06-28

    It has been claimed by others that observed temporal correlations of terrestrial cloud cover with `the cosmic ray intensity' are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We have examined this claim to look for evidence to corroborate it. So far we have not found any and so our tentative conclusions are to doubt it. Such correlations as appear are more likely to be due to the small variations in solar irradiance, which, of course, correlate with cosmic rays. We estimate that less than 15% of the 11-year cycle warming variations are due to cosmic rays and less than 2% of the warming over the last 35 years is due to this cause.

  4. Cosmic Rays and Global Warming

    E-Print Network [OSTI]

    Sloan, T

    2007-01-01

    It has been claimed by others that observed temporal correlations of terrestrial cloud cover with `the cosmic ray intensity' are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We have examined this claim to look for evidence to corroborate it. So far we have not found any and so our tentative conclusions are to doubt it. Such correlations as appear are more likely to be due to the small variations in solar irradiance, which, of course, correlate with cosmic rays. We estimate that less than 15% of the 11-year cycle warming variations are due to cosmic rays and less than 2% of the warming over the last 35 years is due to this cause.

  5. Gamma-Ray Burst Lines

    E-Print Network [OSTI]

    Michael S. Briggs

    1999-10-20

    The evidence for spectral features in gamma-ray bursts is summarized. As a guide for evaluating the evidence, the properties of gamma-ray detectors and the methods of analyzing gamma-ray spectra are reviewed. In the 1980's, observations indicated that absorption features below 100 keV were present in a large fraction of bright gamma-ray bursts. There were also reports of emission features around 400 keV. During the 1990's the situation has become much less clear. A small fraction of bursts observed with BATSE have statistically significant low-energy features, but the reality of the features is suspect because in several cases the data of the BATSE detectors appear to be inconsistent. Furthermore, most of the possible features appear in emission rather than the expected absorption. Analysis of data from other instruments has either not been finalized or has not detected lines.

  6. Miniature x-ray source

    DOE Patents [OSTI]

    Trebes, James E. (Livermore, CA); Bell, Perry M. (Tracy, CA); Robinson, Ronald B. (Modesto, CA)

    2000-01-01

    A miniature x-ray source utilizing a hot filament cathode. The source has a millimeter scale size and is capable of producing broad spectrum x-ray emission over a wide range of x-ray energies. The miniature source consists of a compact vacuum tube assembly containing the hot filament cathode, an anode, a high voltage feedthru for delivering high voltage to the cathode, a getter for maintaining high vacuum, a connector for initial vacuum pump down and crimp-off, and a high voltage connection for attaching a compact high voltage cable to the high voltage feedthru. At least a portion of the vacuum tube wall is fabricated from highly x-ray transparent materials, such as sapphire, diamond, or boron nitride.

  7. Gamma Ray Bursts and CETI

    E-Print Network [OSTI]

    Frank D. Smith Jr

    1993-02-10

    Gamma ray burst sources are isotropically distributed. They could be located at distances $\\sim 1000$ AU. (Katz \\cite{JK92}) GRB signals have many narrow peaks that are unresolved at the millisecond time resolution of existing observations. \\cite{JK87} CETI could use stars as gravitational lenses for interstellar gamma ray laser beam communication. Much better time resolution of GRB signals could rule out (or confirm?) the speculative hypothesis that GRB = CETI.

  8. Thin layer imaging process for microlithography using radiation at strongly attenuated wavelengths

    DOE Patents [OSTI]

    Wheeler, David R.

    2004-01-06

    A method for patterning of resist surfaces which is particularly advantageous for systems having low photon flux and highly energetic, strongly attenuated radiation. A thin imaging layer is created with uniform silicon distribution in a bilayer format. An image is formed by exposing selected regions of the silylated imaging layer to radiation. The radiation incident upon the silyliated resist material results in acid generation which either catalyzes cleavage of Si--O bonds to produce moieties that are volatile enough to be driven off in a post exposure bake step or produces a resist material where the exposed portions of the imaging layer are soluble in a basic solution, thereby desilylating the exposed areas of the imaging layer. The process is self limiting due to the limited quantity of silyl groups within each region of the pattern. Following the post exposure bake step, an etching step, generally an oxygen plasma etch, removes the resist material from the de-silylated areas of the imaging layer.

  9. The bolometric and UV attenuation in normal spiral galaxies of the Herschel Reference Survey

    E-Print Network [OSTI]

    Viaene, S; Bendo, G; Boquien, M; Boselli, A; Ciesla, L; Cortese, L; De Looze, I; Eales, S; Fritz, J; Karczewski, O ?; Madden, S; Smith, M W L; Spinoglio, L

    2015-01-01

    The dust in nearby galaxies absorbs a fraction of the UV-optical-near-infrared radiation produced by stars. This energy is consequently re-emitted in the infrared. We investigate the fraction of the stellar radiation absorbed by spiral galaxies from the HRS by modelling their UV-to-submillimetre spectral energy distributions. Our models provide an attenuated and intrinsic SED from which we find that on average 32 % of all starlight is absorbed by dust. We define the UV heating fraction as the fraction of dust luminosity that comes from absorbed UV photons and find that this is 56 %, on average. This percentage varies with morphological type, with later types having significantly higher UV heating fractions. We find a strong correlation between the UV heating fraction and specific star formation rate and provide a power-law fit. Our models allow us to revisit the IRX-AFUV relations, and derive these quantities directly within a self-consistent framework. We calibrate this relation for different bins of NUV-r c...

  10. POTENTIAL ENHANCEMENTS TO NATURAL ATTENUATION: LINES OF INQUIRY SUPPORTING ENHANCED PASSIVE REMEDIATION OF CHLORINATED SOLVENTS

    SciTech Connect (OSTI)

    Vangelas, K; Tom Early, T; Michael Heitkamp, M; Brian02 Looney, B; David Major, D; Brian Riha, B; Jody Waugh, J; Gary Wein, G

    2004-06-18

    The Department of Energy (DOE) is sponsoring an initiative to facilitate efficient, effective and responsible use of Monitored Natural Attenuation (MNA) and Enhanced Passive Remediation (EPR) for chlorinated solvents. This Office of Environmental Management (EM) ''Alternative Project,'' focuses on providing scientific and policy support for MNA/EPR. A broadly representative working group of scientists supports the project along with partnerships with regulatory organizations such as the Interstate Technology and Regulatory Council and the U.S. Environmental Protection Agency (EPA). The initial product of the technical working group was a summary report that articulated the conceptual approach and central scientific tenants of the project, and that identified a prioritized listing of technical targets for field research. This report documented the process in which: (1) scientific ground rules were developed, (2) lines of inquiry were identified and then critically evaluated, (3) promising applied research topics were highlighted in the various lines of inquiry, and (4) these were discussed and prioritized. The summary report will serve as a resource to guide management and decision-making throughout the period of the subject MNA/EPR Alternative Project. To support and more fully document the information presented in the summary report, we are publishing a series of supplemental documents that present the full texts from the technical analyses within the various lines of inquiry (see listing). The following report - documenting our evaluation of the state of the science of the characterization and monitoring process and tools-- is one of those supplemental documents.

  11. COMPACT BINARY PROGENITORS OF SHORT GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Giacomazzo, Bruno [JILA, University of Colorado and National Institute of Standards and Technology, Boulder, CO 80309 (United States); Perna, Rosalba [JILA and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Rezzolla, Luciano [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Potsdam D-14476 (Germany); Troja, Eleonora [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Lazzati, Davide [Department of Physics, NC State University, 2401 Stinson Drive, Raleigh, NC 27695-8202 (United States)

    2013-01-10

    In recent years, detailed observations and accurate numerical simulations have provided support to the idea that mergers of compact binaries containing either two neutron stars (NSs) or an NS and a black hole (BH) may constitute the central engine of short gamma-ray bursts (SGRBs). The merger of such compact binaries is expected to lead to the production of a spinning BH surrounded by an accreting torus. Several mechanisms can extract energy from this system and power the SGRBs. Here we connect observations and numerical simulations of compact binary mergers, and use the current sample of SGRBs with measured energies to constrain the mass of their powering tori. By comparing the masses of the tori with the results of fully general-relativistic simulations, we are able to infer the properties of the binary progenitors that yield SGRBs. By assuming a constant efficiency in converting torus mass into jet energy, {epsilon}{sub jet} = 10%, we find that most of the tori have masses smaller than 0.01 M{sub Sun }, favoring 'high-mass' binary NSs mergers, i.e., binaries with total masses {approx}> 1.5 the maximum mass of an isolated NS. This has important consequences for the gravitational wave signals that may be detected in association with SGRBs, since 'high-mass' systems do not form a long-lived hypermassive NS after the merger. While NS-BH systems cannot be excluded to be the engine of at least some of the SGRBs, the BH would need to have an initial spin of {approx}0.9 or higher.

  12. 'Self-absorbed' GeV light curves of gamma-ray burst afterglows

    SciTech Connect (OSTI)

    Panaitescu, A.; Vestrand, W. T.; Wo?niak, P. [Space and Remote Sensing, MS B244, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-06-10

    We investigate the effect that the absorption of high-energy (above 100 MeV) photons produced in gamma-ray burst afterglow shocks has on the light curves and spectra of Fermi Large Area Telescope (LAT) afterglows. Afterglows produced by the interaction of a relativistic outflow with a wind-like medium peak when the blast wave deceleration sets in, and the afterglow spectrum could be hardening before that peak, as the optical thickness to pair formation is decreasing. In contrast, in afterglows produced in the interaction with a homogeneous medium, the optical thickness to pair formation should increase and yield a light curve peak when it reaches unity, followed by a fast light curve decay, accompanied by spectral softening. If energy is injected in the blast wave, then the accelerated increase of the optical thickness yields a convex afterglow light curve. Other features, such as a double-peak light curve or a broad hump, can arise from the evolution of the optical thickness to photon-photon absorption. Fast decays and convex light curves are seen in a few LAT afterglows, but the expected spectral softening is rarely seen in (and difficult to measure with) LAT observations. Furthermore, for the effects of photon-photon attenuation to shape the high-energy afterglow light curve without attenuating it too much, the ejecta initial Lorentz factor must be in a relatively narrow range (50-200), which reduces the chance of observing those effects.

  13. Swift monitoring of NGC 5548: X-ray reprocessing and short term UV/optical variability

    E-Print Network [OSTI]

    McHardy, I M; Dwelly, T; Connolly, S; Lira, P; Emmanoulopoulos, D; Gelbord, J; Breedt, E; Arevalo, P; Uttley, P

    2014-01-01

    Lags measured from correlated X-ray/UV/optical monitoring of AGN allow us to determine whether UV/optical variability is driven by reprocessing of X-rays or X-ray variability is driven by UV/optical seed photon variations. We present the results of the largest study to date of the relationship between the X-ray, UV and optical variability in an AGN with 554 observations, over a 750d period, of the Seyfert 1 galaxy NGC 5548 with Swift. There is a good overall correlation between the X-ray and UV/optical bands, particularly on short timescales (tens of days). These bands lag the X-ray band with lags which are proportional to wavelength to the power 1.23+/-0.31. This power is very close to the power (4/3) expected if short timescale UV/optical variability is driven by reprocessing of X-rays by a surrounding accretion disc. The observed lags, however, are longer than expected from a standard Shakura-Sunyaev accretion disc with X-ray heating, given the currently accepted black hole mass and accretion rate values, ...

  14. Three years of Fermi GBM Earth Occultation Monitoring: Observations of Hard X-ray/Soft Gamma-Ray Sources

    E-Print Network [OSTI]

    Wilson-Hodge, Colleen A; Cherry, Michael L; Rodi, James; Camero-Arranz, Ascension; Jenke, Peter; Chaplin, Vandiver; Beklen, Elif; Finger, Mark; Bhat, Narayan; Briggs, Michael S; Connaughton, Valerie; Greiner, Jochen; Kippen, R Marc; Meegan, Charles A; Paciesas, William S; Preece, Robert; von Kienlin, Andreas

    2012-01-01

    The Gamma ray Burst Monitor (GBM) on board Fermi has been providing continuous data to the astronomical community since 2008 August 12. In this paper we present the results of the analysis of the first three years of these continuous data using the Earth occultation technique to monitor a catalog of 209 sources. From this catalog, we detect 102 sources, including 41 low-mass X-ray binary/neutron star systems, 33 high-mass X-ray binary neutron star systems, 12 black hole binaries, 12 active galaxies, 2 other sources, plus the Crab Nebula, and the Sun. Nine of these sources are detected in the 100-300 keV band, including seven black-hole binaries, the active galaxy Cen A, and the Crab. The Crab and Cyg X-1 are also detected in the 300-500 keV band. GBM provides complementary data to other sky-monitors below 100 keV and is the only all-sky monitor above 100 keV. Up-to-date light curves for all of the catalog sources can be found at http://heastro.phys.lsu.edu/gbm/.

  15. Gamma ray bursts ROBERT S MACKAY

    E-Print Network [OSTI]

    Rourke, Colin

    Gamma ray bursts ROBERT S MACKAY COLIN ROURKE We propose that a gamma ray burst is a kinematic Gamma ray bursts are intense flashes of electromagnetic radiation of cosmic origin lasting from ten accepted mechanism. We propose that a gamma ray burst is simply a kinematic effect, namely the effect

  16. Gamma-Ray Bursts, Ultra High Energy Cosmic Rays, and Cosmic Gamma-Ray Background

    E-Print Network [OSTI]

    Tomonori Totani

    1999-04-13

    We argue that gamma-ray bursts (GRBs) may be the origin of the cosmic gamma-ray background radiation observed in GeV range. It has theoretically been discussed that protons may carry a much larger amount of energy than electrons in GRBs, and this large energy can be radiated in TeV range by synchrotron radiation of ultra-high-energy protons (\\sim 10^{20} eV). The possible detection of GRBs above 10 TeV suggested by the Tibet and HEGRA groups also supports this idea. If this is the case, most of TeV gamma-rays from GRBs are absorbed in intergalactic fields and eventually form GeV gamma-ray background, whose flux is in good agreement with the recent observation.

  17. CHARACTERIZING ULTRAVIOLET AND INFRARED OBSERVATIONAL PROPERTIES FOR GALAXIES. I. INFLUENCES OF DUST ATTENUATION AND STELLAR POPULATION AGE

    SciTech Connect (OSTI)

    Mao Yewei; Kong Xu [Center for Astrophysics, University of Science and Technology of China, Hefei 230026 (China); Kennicutt, Robert C. Jr. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA (United Kingdom); Hao, Cai-Na [Tianjin Astrophysics Center, Tianjin Normal University, Tianjin 300387 (China); Zhou Xu, E-mail: owen81@mail.ustc.edu.cn, E-mail: xkong@ustc.edu.cn [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2012-09-20

    The correlation between infrared-to-ultraviolet luminosity ratio and ultraviolet color (or ultraviolet spectral slope), i.e., the IRX-UV (or IRX-{beta}) relation, found in studies of starburst galaxies is a prevalent recipe for correcting extragalactic dust attenuation. Considerable dispersion in this relation discovered for normal galaxies, however, complicates its usability. In order to investigate the cause of the dispersion and to have a better understanding of the nature of the IRX-UV relation, in this paper, we select five nearby spiral galaxies, and perform spatially resolved studies on each of the galaxies, with a combination of ultraviolet and infrared imaging data. We measure all positions within each galaxy and divide the extracted regions into young and evolved stellar populations. By means of this approach, we attempt to discover separate effects of dust attenuation and stellar population age on the IRX-UV relation for individual galaxies. In this work, in addition to dust attenuation, stellar population age is interpreted to be another parameter in the IRX-UV function, and the diversity of star formation histories is suggested to disperse the age effects. At the same time, strong evidence shows the need for more parameters in the interpretation of observational data, such as variations in attenuation/extinction law. Fractional contributions of different components to the integrated luminosities of the galaxies suggest that the integrated measurements of these galaxies, which comprise different populations, would weaken the effect of the age parameter on IRX-UV diagrams. The dependence of the IRX-UV relation on luminosity and radial distance in galaxies presents weak trends, which offers an implication of selective effects. The two-dimensional maps of the UV color and the infrared-to-ultraviolet ratio are displayed and show a disparity in the spatial distributions between the two galaxy parameters, which offers a spatial interpretation of the scatter in the IRX-UV relation.

  18. Quantization of surface plasmon polariton on the metal slab by Green's tensor method in amplifying and attenuating media

    E-Print Network [OSTI]

    Z. Allameh; R. Roknizadeh; R. Masoudi

    2015-07-15

    A quantized form of Surface Plasmon Polariton (SPP) modes propagating on the metal thin film is provided, which is based on the Green's tensor method. Since the media will be considered lossy and dispersive, the amplification and attenuation of the SPP modes in various dielectric media, by applying different field frequencies, can be studied. We will also illustrate the difference between behavior of coherent and squeezed SPP modes in the amplifying media.

  19. X-ray Detection from Bona-fide and Candidate Brown Dwarfs in the Rho Ophiuchi Cloud with Chandra

    E-Print Network [OSTI]

    Kensuke Imanishi; Masahiro Tsujimoto; Katsuji Koyama

    2001-08-06

    We present results of an X-ray search from bona-fide and candidate brown dwarfs in the Rho Ophiuchi cloud cores with the Chandra X-ray Observatory. The selected areas are two fields near the cloud center and are observed with the ACIS-I array of a 17'x17' size and a ~100 ks exposure. Among 18 bona-fide and candidate brown dwarfs listed by the infrared spectroscopy, we find X-ray emission from 7 sources above 99.9% confidence level. Therefore ~40% of the infrared-selected brown dwarfs in this cloud emit X-rays. For the brightest 4 sources, the X-ray spectra are made and are fitted with a thin-thermal plasma model of a temperature 1-2.5 keV. The X-rays are also time variable with rapid flares from 2 of the brown dwarfs. Assuming 2 keV temperature and using the empirical relation of Av vs. NH, we estimate the X-ray luminosity or its upper limit of the other faint or non-X-ray sources. The X-ray luminosity (Lx) of the X-ray-detected sources is in the range of 0.3-90x10^28 ergs s^-1, while the luminosity ratio of X-ray to bolometric (Lx/Lbol) is 10^-3 - 10^-5, similar to those of low-mass pre-main-sequence and dMe stars. All these results suggest that the X-ray origin of brown dwarfs is the same as low-mass stars; strong magnetic activity at the stellar surface.

  20. Mass Exchange Processes with Input

    E-Print Network [OSTI]

    P. L. Krapivsky

    2015-03-07

    We investigate a system of interacting clusters evolving through mass exchange and supplemented by input of small clusters. Three possibilities depending on the rate of exchange generically occur when input is homogeneous: continuous growth, gelation, and instantaneous gelation. We mostly study the growth regime using scaling methods. An exchange process with reaction rates equal to the product of reactant masses admits an exact solution which allows us to justify the validity of scaling approaches in this special case. We also investigate exchange processes with a localized input. We show that if the diffusion coefficients are mass-independent, the cluster mass distribution becomes stationary and develops an algebraic tail far away from the source.