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1

NIST X-Ray Mass Attenuation Coefficients - Version History  

Science Conference Proceedings (OSTI)

... year, month day with database access date.) Hubbell, JH and Seltzer, SM (2004), Tables of X-Ray Mass Attenuation Coefficients and Mass Energy- ...

2010-10-05T23:59:59.000Z

2

NIST: X-Ray Mass Attenuation Coefficients  

Science Conference Proceedings (OSTI)

... NIST reserves the right to charge for these data in the ... ?/? and the mass energy-absorption coefficient ... The tables cover energies of the photon (x-ray ...

2011-12-09T23:59:59.000Z

3

X-ray attenuation properties of stainless steel (u)  

SciTech Connect

Stainless steel vessels are used to enclose solid materials for studying x-ray radiolysis that involves gas release from the materials. Commercially available stainless steel components are easily adapted to form a static or a dynamic condition to monitor the gas evolved from the solid materials during and after the x-ray irradiation. Experimental data published on the x-ray attenuation properties of stainless steel, however, are very scarce, especially over a wide range of x-ray energies. The objective of this work was to obtain experimental data that will be used to determine how a poly-energetic x-ray beam is attenuated by the stainless steel container wall. The data will also be used in conjunction with MCNP (Monte Carlos Nuclear Particle) modeling to develop an accurate method for determining energy absorbed in known solid samples contained in stainless steel vessels. In this study, experiments to measure the attenuation properties of stainless steel were performed for a range of bremsstrahlung x-ray beams with a maximum energy ranging from 150 keV to 10 MeV. Bremsstrahlung x-ray beams of these energies are commonly used in radiography of engineering and weapon components. The weapon surveillance community has a great interest in understanding how the x-rays in radiography affect short-term and long-term properties of weapon materials.

Wang, Lily L [Los Alamos National Laboratory; Berry, Phillip C [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

4

NIST: X-Ray Mass Attenuation Coefficients - Mercury  

Science Conference Proceedings (OSTI)

Table of Contents Back to table 3 Mercury Z = 80 HTML table format. Energy, ?/?, ? en /?. (MeV), (cm 2 /g), (cm 2 /g). 1.00000 ...

5

NIST: X-Ray Mass Attenuation Coefficients - Section 2  

Science Conference Proceedings (OSTI)

... atom interactions, such as nuclear-resonance scattering ... them to the high-energy asymptotic values ... formulas from Bethe-Heitler theory with various ...

6

NIST: X-Ray Mass Attenuation Coefficients - Calcium Fluoride  

Science Conference Proceedings (OSTI)

Table of Contents Back to table 4 Calcium Fluoride HTML table format. Energy, ?/?, ? en /?. (MeV), (cm 2 /g), (cm 2 /g). 1.00000 ...

7

NIST: X-Ray Mass Attenuation Coefficients - Uranium  

Science Conference Proceedings (OSTI)

Table of Contents Back to table 3 Uranium Z = 92 HTML table format. Energy, ?/?, ? en /?. (MeV), (cm 2 /g), (cm 2 /g). 1.00000 ...

8

NIST: X-Ray Mass Attenuation Coefficients - Table 2  

Science Conference Proceedings (OSTI)

... 0.406778. Tissue-Equivalent Gas, Propane Based, 0.55027, 59.5, 1.826E-03, 1: 0.102676 6: 0.568937 7: 0.035022 8: 0.293365. ...

9

NIST: X-Ray Mass Attenuation Coefficients - Table 4  

Science Conference Proceedings (OSTI)

... Gafchromic Sensor, Tissue-Equivalent Gas, Methane Based. Gallium Arsenide, Tissue-Equivalent Gas, Propane Based. Glass ...

10

NIST: X-Ray Mass Attenuation Coefficients - Thorium  

Science Conference Proceedings (OSTI)

Table of Contents Back to table 3 Thorium Z = 90 HTML table format. Energy, ?/?, ? en /?. (MeV), (cm 2 /g), (cm 2 /g). 1.00000 ...

11

NIST: X-Ray Mass Attenuation Coefficients - Table 3  

Science Conference Proceedings (OSTI)

... 28, Ni, Nickel, 51, Sb, Antimony, 74, W, Tungsten. 6, C, Carbon, Graphite, 29, Cu, Copper, 52, Te, Tellurium, 75, Re, Rhenium. 7, N, Nitrogen, 30, Zn, ...

12

NIST: X-Ray Mass Attenuation Coefficients - Table 1  

Science Conference Proceedings (OSTI)

... 28, Ni, Nickel, 0.47708, 311.0, 8.902E+00. 29, Cu, Copper, 0.45636, 322.0, 8.960E+00. 30, Zn, Zinc, 0.45879, 330.0, 7.133E+00. ...

13

NIST: X-Ray Mass Attenuation Coefficients - Hydrogen  

Science Conference Proceedings (OSTI)

Table of Contents Back to table 3 Hydrogen Z = 1 HTML table format. Energy, ?/?, ? en /?. (MeV), (cm 2 /g), (cm 2 /g). 1.00000 ...

14

NIST: X-Ray Mass Attenuation Coefficients - References  

Science Conference Proceedings (OSTI)

... and Scofield, JH (1989), Tables and Graphs of Photon-Interaction Cross Sections from 10 eV to 100 GeV Derived from the LLNL Evaluated Photon ...

15

MASS BALANCE: A KEY TO ADVANCING MONITORED AND ENHANCED ATTENUATION FOR CHLORINATED SOLVENTS  

SciTech Connect

Monitored natural attenuation (MNA) and enhanced attenuation (EA) are two environmental management strategies that rely on a variety of attenuation processes to degrade or immobilize contaminants and are implemented at appropriate sites by demonstrating that contaminant plumes have low risk and are stable or shrinking. The concept of a mass balance between the loading and attenuation of contaminants in a groundwater system is a powerful framework for conceptualizing and documenting the relative stability of a contaminant plume. As a result, this concept has significant potential to support appropriate implementation of monitored natural attenuation (MNA) and enhanced attenuation (EA). For mass balance to be useful in engineering practice, however, it is necessary to quantify it in practical ways that facilitate overall site remediation and which are consistent with existing regulatory guidance. Two divergent philosophies exist for quantifying plume stability--empirical and deterministic. The first relies on historical contaminant concentration data and bulk geochemical information from a monitoring well network and documents plume stability using trend analysis and statistical tools. This empirical approach, when feasible, provides powerful and compelling documentation of plume behavior and mass balance. It provides an interpretation on a relevant scale under field conditions. It integrates the operative attenuation processes measured by observing their actual impact on the plume. The power of the empirical approach was recognized early in the development of MNA guidance and protocols and it is currently the basis of the three lines of evidence used in MNA studies. The empirical approach has some weaknesses, however. It requires a relatively long period of undisturbed historical data. Thus it cannot be effectively applied to sites where active remediation was initiated quickly and is currently operating. It cannot be used as a tool to determine how much source removal is needed or when to turn off active remediation and transition to MNA. It cannot be used to evaluate potential enhancement options (unless a long period of post enhancement monitoring is planned). It provides only indirect information about process and treats the plume as a ''black box''. The empirical approach has the advantage that, when sufficient monitoring data are available, the attenuation capacity can be defined inexpensively and with a high degree of certainty. Alternatively, a deterministic approach can be used to assess mass balance and plume stability. In this approach, the physical, chemical, and biological attenuation processes are used to assess contaminant loading and attenuation. The deterministic approach has the advantage that, when sufficient hydrologic, geochemical, and microbiological data are available, it is possible to project how a system will respond to contaminant removal actions or enhancements of natural attenuation processes. The ''black box'' of the plume is taken apart, quantified, and put back together again. The disadvantage of the deterministic approach is that it is difficult to measure all or most of the relevant hydrologic, geochemical, and biological parameters with any certainty. Case studies over the past decade demonstrate that empirical and deterministic approaches to MNA/EA are not mutually exclusive. These studies document that improved decision support and efficiency result by combining these methods based on the individual challenges presented by a given site. Whenever possible, the empirical approach is used to quantify mass loading and attenuation capacity (mass of contaminant/unit time) at particular sites. This is the most effective way to demonstrate the efficiency of ongoing natural attenuation processes in accordance with current regulatory guidance. But in addition, the monitoring well networks needed to apply the empirical approach can also yield estimates of the hydrologic, geochemical, and biological parameters needed to apply deterministic models. These models can then be used to estimate how cont

Looney, B; Karen Vangelas, K; Karen-M Adams, K; Francis H. Chappelle; Tom O. Early; Claire H. Sink

2006-06-30T23:59:59.000Z

16

Testing Mass Varying Neutrino With Short Gamma Ray Burst  

E-Print Network (OSTI)

In this paper we study the possibility of probing for the absolute neutrino mass and its variation with short Gamma Ray Burst (GRB). We have calculated the flight time difference between a massive neutrino and a photon in two different approaches to mass varying neutrinos. Firstly we parametrize the neutrino mass as a function of redshift in a model independent way, then we consider two specific models where the neutrino mass varies during the evolution of the Quintessence fields. Our calculations show in general the value of the time delay is changed substantially relative to a constant neutrino mass. Furthermore our numerical results show that the flight time delay in these models is expected to be larger than the duration time of the short GRB, which opens a possibility of testing the scenario of mass varying neutrino with the short GRB.

Hong Li; Zigao Dai; Xinmin Zhang

2004-11-17T23:59:59.000Z

17

X-ray Flares in Orion Low Mass Stars  

E-Print Network (OSTI)

Context. X-ray flares are common phenomena in pre-main sequence stars. Their analysis gives insights into the physics at work in young stellar coronae. The Orion Nebula Cluster offers a unique opportunity to study large samples of young low mass stars. This work is part of the Chandra Orion Ultradeep project (COUP), an ~10 day long X-ray observation of the Orion Nebula Cluster (ONC). Aims. Our main goal is to statistically characterize the flare-like variability of 165 low mass (0.1-0.3 M_sun) ONC members in order to test and constrain the physical scenario in which flares explain all the observed emission. Methods. We adopt a maximum likelihood piece-wise representation of the observed X-ray light curves and detect flares by taking into account both the amplitude and time derivative of the count-rate. We then derive the frequency and energy distribution of the flares. Results. The high energy tail of the energy distribution of flares is well described by a power-law with index 2.2. We test the hypothesis that light curves are built entirely by overlapping flares with a single power law energy distribution. We constrain the parameters of this simple model for every single light curve. The analysis of synthetic light curves obtained from the model indicates a good agreement with the observed data. Comparing low mass stars with stars in the mass interval (0.9-1.2M_sun), we establish that, at ~1 Myr, low mass and solar mass stars of similar X-ray luminosity have very similar flare frequencies. Conclusions. Our observational results are consistent with the following model/scenario: the light curves are entirely built by over- lapping flares with a power-law intensity distribution; the intense flares are individually detected, while the weak ones merge and form a pseudo-quiescent level, which we indicate as the characteristic level.

M. Caramazza; E. Flaccomio; G. Micela; F. Reale; S. J. Wolk; E. D. Feigelson

2007-06-11T23:59:59.000Z

18

A COMPARISON OF MEASURED AND CALCULATED GAMMA RAY ATTENUATION FOR A COMMON COUNTING GEOMETRY  

Science Conference Proceedings (OSTI)

In order to perform quantitative gamma spectroscopy, it is necessary to know the sample-specific detection efficiency for photons as a function of energy. The detection efficiency, along with the branching ratio for the isotope and gamma ray of interest, is used to convert observed counts/second to actual disintegrations/second, and, hence, has a large effect on the accuracy of the measurement. In cases where the geometry of the source is simple and reproducible, such as a point source, small vial of solid, or jar of liquid, geometry-specific standards may be counted to determine the detection efficiency. In cases where the samples are large, irregular, or unique, this method generally cannot be used. For example, it is impossible to obtain a NIST-traceable standard glovebox or 55-gallon drum. In these cases, a combination of measured absolute detector efficiency and calculated sample-specific correction factors is commonly used. The correction factors may be calculated via Monte Carlo simulation of the item (the method used by Canberra's ISOCS system), or via semi-empirical calculation of matrix and container attenuations based on the thickness and composition of the container and radioactive matrix (ISOTOPIC by EG&G Ortec uses this method). The accuracy of these correction factors for specific geometries is often of vital interest when assessing the quality of gamma spectroscopy data. During the Building 251 Risk-Reduction Project, over 100 samples of high activity actinides will be characterized via gamma spectroscopy, typically without removing the material from the current storage containers. Most of the radioactive materials in B-251 are stored in cylindrical stainless steel canisters (called USV containers, after the Underground Storage Vaults they are commonly stored in), 13 cm in diameter, by 28 cm high, with walls that are 1.8 mm thick. While the actual samples have a variety of configurations inside the USV container, a very common configuration is the material (usually as an oxide powder pellet of approximately 2 cm diameter by {approx}2 mm thick) in a squat glass jar, with the jar placed in a thin steel food-pack can, which is then placed in the bottom of the USV canister. During data acquisition, the USV containers are typically rotated at approximately 4 rpm on a turntable to eliminate errors due to the material not being centered in the can, or attenuation not being isotropic. An aluminum plate is placed over the container, secured by three vertical rods, to securely hold the container. Pictures of both the containers, and this typical counting configuration are shown below.

Gaylord, R F

2004-02-26T23:59:59.000Z

19

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

SciTech Connect

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.

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

2013-07-20T23:59:59.000Z

20

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

E-Print Network (OSTI)

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

Jackman, Charles H.

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

The Mass of the Compact Object in the Low-Mass X-ray Binary 2S 0921-630  

E-Print Network (OSTI)

We interpret the observed radial-velocity curve of the optical star in the low-mass X-ray binary 2S 0921-630 using a Roche model, taking into account the X-ray heating of the optical star and screening of X-rays coming from the relativistic object by the accretion disk. Consequences of possible anisotropy of the X-ray radiation are considered.We obtain relations between the masses of the optical and compact (X-ray) components, mv and mx, for orbital inclinations i=60, 75, 90 degrees. Including X-ray heating enabled us to reduce the compact object's mass by near 0.5-1Msun, compared to the case with no heating. Based on the K0III spectral type of the optical component (with a probable mass of mv=2.9Msun, we concluded that mx=2.45-2.55Msun (for i=75-90 degrees). If the K0III star has lost a substantial part of its mass as a result of mass exchange, as in the V404 Cyg and GRS 1905+105 systems, and its mass is $m_v=0.65-0.75Msun, the compact object's mass is close to the standard mass of a neutron star, mx=1.4Msun...

Abubekerov, M K; Cherepashchuk, A M; Shimanskii, V V

2012-01-01T23:59:59.000Z

22

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

E-Print Network (OSTI)

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 ...

Lin, Dacheng

2009-01-01T23:59:59.000Z

23

Relating x-ray attenuation measurements to water content and distribution in SB-15D core  

DOE Green Energy (OSTI)

Making improved estimates of the water content of The Geysers reservoir is fundamental to efficient and economic long term production of steam power from the resource. A series of coordinated physical properties measurements form core recovered from the SB-15D, reported in this volume in a series of papers, have been made to better understand water storage and to relate water content and distribution to observable geophysical properties such as electrical conductivity and seismic velocities. A principal objective here is to report new interpretations of x-ray scans made within 72 hours of core recovery from SB-15D, which suggest, taking advantage of preliminary measurements of capillary suction for metagraywacke, that water content was low in much of the preserved core.

Bonner, B.P.; Roberts, J.J.; Schneberk, D.J

1996-09-30T23:59:59.000Z

24

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

E-Print Network (OSTI)

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. ...

Krauss, Miriam Ilana

2007-01-01T23:59:59.000Z

25

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

E-Print Network (OSTI)

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.

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

1998-05-19T23:59:59.000Z

26

Timing the Kilohertz Quasi-Periodic Oscillations in Low-mass X-ray Binaries  

E-Print Network (OSTI)

I describe a new technique that we have been using in the past few years to get precise measurements of the frequency separation of the kHz QPOs in some Low-mass X-ray binaries. I show how this technique (that we call "shift-and-add") works, and I present some of the results we obtained using it.

Mariano Mendez

2000-06-19T23:59:59.000Z

27

DISCRETE MASS EJECTIONS FROM THE Be/X-RAY BINARY A0535+26/HD 245770  

SciTech Connect

We present long-term optical spectroscopic observations on the Be/X-ray binary A0535+26 from 1992 to 2010. Combined with the public V-band photometric data, we find that each giant X-ray outburst occurred in a fading phase of the optical brightness. The anti-correlation between the optical brightness and the H{alpha} intensity during our 2009 observations indicates a mass ejection event had taken place before the 2009 giant X-ray outburst, which might cause the formation of a low-density region in the inner part of the disk. The similar anti-correlation observed around 1996 September indicates the occurrence of the mass ejection, which might trigger the subsequent disk loss event in A0535+26.

Yan Jingzhi; Li Hui; Liu Qingzhong, E-mail: jzyan@pmo.ac.cn, E-mail: hli@pmo.ac.cn, E-mail: qzliu@pmo.ac.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing (China)

2012-01-01T23:59:59.000Z

28

A new method of alpha ray measurement using a Quadrupole Mass Spectrometer  

E-Print Network (OSTI)

We propose a new method of alpha($\\alpha$)-ray measurement that detects helium atoms with a Quadrupole Mass Spectrometer(QMS). A demonstration is undertaken with a plastic-covered $^{241}$Am $\\alpha$-emitting source to detect $\\alpha$-rays stopped in the capsule. We successfully detect helium atoms that diffuse out of the capsule by accumulating them for one to 20 hours in a closed chamber. The detected amount is found to be proportional to the accumulation time. Our method is applicable to probe $\\alpha$-emitting radioactivity in bulk material.

Y. Iwata; Y. Inoue; M. Minowa

2007-04-16T23:59:59.000Z

29

Hydrogen deficient donors in low-mass X-ray binaries  

E-Print Network (OSTI)

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.

Gijs Nelemans

2007-11-05T23:59:59.000Z

30

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

Science Conference Proceedings (OSTI)

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.

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)

2012-11-10T23:59:59.000Z

31

An INTEGRAL view of High Mass X-ray Binaries : their nature, formation and evolution  

E-Print Network (OSTI)

We describe here the nature, formation and evolution of the supergiant high mass X-ray binary (HMXB) population, i.e. systems accreting the stellar wind of supergiant stars. There are now many new observations, from the high-energy side (mainly from the INTEGRAL satellite), complemented by multi-wavelength observations (mainly in the optical, near and mid-infrared from ESO facilities), showing that a new population of supergiant HMXBs has been recently revealed. We report here on the observational facts about the different categories of HMXBs, allowing to build a consistent scenario explaining the various characteristics of these sources, based on models of accretion in these sources (e.g. transitory accretion disc versus clumpy winds). We also mention new observations suggesting the existence of evolutionary links between Be and stellar wind accreting supergiant X-ray binaries.

Chaty, Sylvain

2013-01-01T23:59:59.000Z

32

SRNL - Natural Attenuation Monitor  

NLE Websites -- All DOE Office Websites (Extended Search)

Natural Attenuation Monitor covers Natural Attenuation Monitor Published by the US DOE Monitored Natural Attenuation and Enhanced Attenuation for Chlorinated Solvents Technology...

33

Enhancement of Terrestrial Diffuse X-ray Emission Associated With Coronal Mass Ejection and Geomagnetic Storm  

E-Print Network (OSTI)

We present an analysis of a Suzaku observation taken during the geomagnetic storm of 2005 August 23-24. We found time variation of diffuse soft X-ray emission when a coronal mass ejection hit Earth and caused a geomagnetic storm. The diffuse emission consists of fluorescent scattering of solar X-rays and exospheric solarwind charge exchange. The former is characterized by a neutral oxygen emission line due to strong heating of the upper atmosphere during the storm time, while the latter is dominated by a sum of C V, C VI, N VI, N VII, O VII, and O VIII emission lines due to the enhanced solar wind flux in the vicinity of the exosphere. Using the solar wind data taken with the ACE and WIND satellites,a time correlation between the solar wind and the strong O VII line flux were investigated. We estimated necessary column densities for the solar X-ray scattering and exospheric SWCX. From these results, we argue that a part of the solar wind ions enter inside the magnetosphere and cause the SWCX reaction.

Ezoe, Yuichiro; Yoshitake, Hiroshi; Mitsuda, Kazuhisa; Terada, Naoki; Oishi, Shihoko; Ohashi, Takaya

2011-01-01T23:59:59.000Z

34

Hydrostatic equilibrium of a porous intracluster medium: implications for mass fraction and X-ray luminosity  

E-Print Network (OSTI)

The presence of dilute hot cavities in the intracluster medium (ICM) at the cores of clusters of galaxies changes the relation between gas temperature and its X-ray emission properties. Using the hydrostatic equations of a porous medium we solve for the ICM density for a given temperature as a function of the filling factor of dilute bubbles. We find that at a given temperature, the core X-ray luminosity increases with the filling factor. If the frequency of AGNs in clusters were higher in the past, then the filling factor could correspondingly be significant, with implications for the cluster scaling relations at high redshifts. This is especially important for the core properties, including the temperature-luminosity ($L_X-T$) relation and estimates of the core gas mass. The results imply an epoch-dependent sensitivity of the $L_X-T$ relation in the core to the porosity of the ICM. Detection of such an effect would give new insights into AGN feedback.

Adi Nusser; Joe Silk

2007-11-08T23:59:59.000Z

35

Unidentified gamma-ray sources off the Galactic plane as low-mass microquasars?  

E-Print Network (OSTI)

A subset of the unidentified EGRET gamma-ray sources with no active galactic nucleus or other conspicuous counterpart appears to be concentrated at medium latitudes. Their long-term variability and their spatial distribution indicate that they are distinct from the more persistent sources associated with the nearby Gould Belt. They exhibit a large scale height of 1.3 +/- 0.6 kpc above the Galactic plane. Potential counterparts for these sources include microquasars accreting from a low-mass star and spewing a continuous jet. Detailed calculations have been performed of the jet inverse Compton emission in the radiation fields from the star, the accretion disc, and a hot corona. Different jet Lorentz factors, powers, and aspect angles have been explored. The up-scattered emission from the corona predominates below 100 MeV whereas the disc and stellar contributions are preponderant at higher energies for moderate (~15 deg) and small (~1 deg) aspect angles, respectively. Yet, unlike in the high-mass, brighter versions of these systems, the external Compton emission largely fails to produce the luminosities required for 5 to 10 kpc distant EGRET sources. Synchrotron-self-Compton emission appears as a promising alternative.

I. A. Grenier; M. M. Kaufman Bernado; G. E. Romero

2004-08-12T23:59:59.000Z

36

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

E-Print Network (OSTI)

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.

Suchy, Slawomir

2011-01-01T23:59:59.000Z

37

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

E-Print Network (OSTI)

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).

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

2007-12-06T23:59:59.000Z

38

Measuring the Dark Matter Halo Mass of X-ray AGN at z~1 using photometric redshifts  

E-Print Network (OSTI)

Data from the AEGIS, COSMOS and ECDFS surveys are combined to infer the bias and dark matter halo mass of moderate luminosity [LX(2-10 keV) = 42.9 erg s-1] X-ray AGN at z~1 via their cross-correlation function with galaxies. In contrast to standard cross-correlation function estimators, we present a method that requires spectroscopy only for the AGN and uses photometric redshift probability distribution functions for galaxies to determine the projected real-space AGN/galaxy cross-correlation function. The estimated dark matter halo mass of X-ray AGN in the combined AEGIS, COSMOS and ECDFS fields is ~13h-1M_solar, in agreement with previous studies at similar redshift and luminosity ranges. Removing from the sample the 5 per cent of the AGN associated with X-ray selected groups results in a reduction by about 0.5 dex in the inferred AGN dark matter halo mass. The distribution of AGN in dark matter halo mass is therefore skewed and the bulk of the population lives in moderate mass haloes. This result favour col...

Mountrichas, G; Finoguenov, A; Erfanianfar, G; Cooper, M C; Coil, A L; Laird, E S; Nandra, K; Newman, J A

2012-01-01T23:59:59.000Z

39

ON THE ORIGIN OF THE METALLICITY DEPENDENCE IN DYNAMICALLY FORMED EXTRAGALACTIC LOW-MASS X-RAY BINARIES  

Science Conference Proceedings (OSTI)

Globular clusters (GCs) effectively produce dynamically formed low-mass X-ray binaries (LMXBs). Observers detect {approx}100 times more LMXBs per stellar mass in GCs compared to stars in the fields of galaxies. Observationally, metal-rich GCs are about three times more likely to contain an X-ray source than their metal-poor counterparts. Recent observations have shown that this ratio holds in extragalactic GCs for all bright X-ray sources with L{sub X} between 2 Multiplication-Sign 10{sup 37} and 5 Multiplication-Sign 10{sup 38} erg s{sup -1}. In this Letter, we propose that the observed metallicity dependence of LMXBs in extragalactic GCs can be explained by the differences in the number densities and average masses of red giants in populations of different metallicities. Red giants serve as seeds for the dynamical production of bright LMXBs via two channels-binary exchanges and physical collisions-and the increase of the number densities and masses of red giants boost LMXB production, leading to the observed difference. We also discuss a possible effect of the age difference in stellar populations of different metallicities.

Ivanova, N.; Avendano Nandez, J. L.; Sivakoff, G. R. [Department of Physics, University of Alberta, Edmonton, AB T6G 2E1 (Canada); Fragos, T.; Kim, D.-W.; Fabbiano, G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Lombardi, J. C. [Department of Physics, Allegheny College, Meadville, PA 16335 (United States); Voss, R. [Department of Astrophysics/IMAPP, Radboud University Nijmegen, P.O. Box 9010, 6500-GL Nijmegen (Netherlands); Jordan, A., E-mail: nata.ivanova@ualberta.ca [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, 7820436 Macul, Santiago (Chile)

2012-12-01T23:59:59.000Z

40

The Lx-Yx Relation: Using Galaxy Cluster X-Ray Luminosity as a Robust, Low Scatter Mass Proxy  

E-Print Network (OSTI)

We use a sample of 115 galaxy clusters at 0.1mass and temperature). The scatter in the relation is dominated by cluster cores, and a tight LY relation (11% intrinsic scatter in Lx) is recovered if sufficiently large core regions (0.15R500) are excluded. The intrinsic scatter is well described by a lognormal distribution and the relations are consistent for relaxed and disturbed/merging clusters. We investigate the LY relation in low-quality data (e.g. for clusters detected in X-ray survey data) by estimating Lx from soft band count rates, and find that the scatter increases somewhat to 21%. We confirm the tight correlation between Yx and mass and the self-similar evolution of that scaling relation out to z=0.6 for a subset of clusters in our sample with mass estimates from the literature. This is used to estimate masses for the entire sample and hence measure the LM relation. We find that the scatter in the LM relation is much lower than previous estimates, due to the full removal of cluster cores and more robust mass estimates. For high-redshift clusters the scatter in the LM relation remains low if cluster cores are not excluded. These results suggest that cluster masses can be reliably estimated from simple luminosity measurements in low quality data where direct mass estimates, or measurements of Yx are not possible. This has important applications in the estimation of cosmological parameters from X-ray cluster surveys.

B. J. Maughan

2007-03-19T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
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41

CONSTRAINTS ON THE COMPACT OBJECT MASS IN THE ECLIPSING HIGH-MASS X-RAY BINARY XMMU J013236.7+303228 IN M 33  

SciTech Connect

We present optical spectroscopic measurements of the eclipsing high-mass X-ray binary (HMXB) XMMU J013236.7+303228 in M 33. Based on spectra taken at multiple epochs of the 1.73 day binary orbital period we determine physical as well as orbital parameters for the donor star. We find the donor to be a B1.5IV subgiant with effective temperature T = 22, 000-23, 000 K. From the luminosity, temperature, and known distance to M 33 we derive a radius of R 8.9 {+-} 0.5 R{sub Sun }. From the radial-velocity measurements, we determine a velocity semi-amplitude of K{sub opt} = 63 {+-} 12 km s{sup -1}. Using the physical properties of the B star determined from the optical spectrum, we estimate the star's mass to be M{sub opt} = 11 {+-} 1 M{sub Sun }. Based on the X-ray spectrum, the compact companion is likely a neutron star, although no pulsations have yet been detected. Using the spectroscopically derived B star mass we find the neutron star companion mass to be M{sub X} = 2.0 {+-} 0.4 M{sub Sun }, consistent with the neutron star mass in the HMXB Vela X-1, but heavier than the canonical value of 1.4 M{sub Sun} found for many millisecond pulsars. We attempt to use as an additional constraint that the B star radius inferred from temperature, flux, and distance should equate to the Roche radius, since the system accretes by Roche lobe overflow. This leads to substantially larger masses, but by trying to apply the technique to known systems, we find that the masses are consistently overestimated. Attempting to account for that in our uncertainties, we derive M{sub X} = 2.2{sup +0.8}{sub -0.6} M{sub Sun} and M{sub opt} = 13 {+-} 4 M{sub Sun }. We conclude that precise constraints require detailed modeling of the shape of the Roche surface.

Bhalerao, Varun B.; Harrison, Fiona A. [Cahill Center for Astrophysics, California Institute of Technology, Pasadena, CA 91125 (United States); Van Kerkwijk, Marten H. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)

2012-09-20T23:59:59.000Z

42

Vaporizing neutron stars in low-mass x-ray binaries and the statistics of millisecond pulsars  

SciTech Connect

Recent data on low-mass X-ray binaries (LMXBs) and msec pulsars (MSPs) pose a challenge to evolutionary which neglect the effects of disk and companion irradiation. Here we discuss the main features of a radiation-driven (RD) evolutionary model that may be applicable to several LMXBs. According to this model, irradiation from the accreting compact star LMXBs vaporizes'' the accretion disk and the companion star by driving a self-sustained mass loss until a sudden accretion-turn of occurs. The main characteristics of the RD-evolution are: (1) the lifetime of RD-LMXB's is of order 10{sup 7} years or less: (2) both the orbital period gap and the X-ray luminosity may be consequences of RD-evolution of LMXB's containing lower main sequence and degenerate companion stars; (3) the companion star may transfer mass to the primary even if it underfills its Roche lobe; (4) the recycled msec pulsar can continue to vaporize the low-mass companion star even after the accretion turn-off produced by a strong pulsar wind; (5) the RD-evolutionary model resolves the apparent statistical discrepancy between the number of MSP's and their LMXB progenitors. 14 refs., 1 fig., 1 tab.

Tavani, M. (California Univ., Livermore, CA (United States). Inst. of Geophysics and Planetary Physics)

1991-08-08T23:59:59.000Z

43

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

SciTech Connect

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)

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)

2005-01-01T23:59:59.000Z

44

A COMPARISON OF BROAD IRON EMISSION LINES IN ARCHIVAL DATA OF NEUTRON STAR LOW-MASS X-RAY BINARIES  

SciTech Connect

Relativistic X-ray disklines have been found in multiple neutron star low-mass X-ray binaries, in close analogy with black holes across the mass scale. These lines have tremendous diagnostic power and have been used to constrain stellar radii and magnetic fields, often finding values that are consistent with independent timing techniques. Here, we compare CCD-based data from Suzaku with Fe K line profiles from archival data taken with gas-based spectrometers. In general, we find good consistency between the gas-based line profiles from EXOSAT, BeppoSAX, and RXTE and the CCD data from Suzaku, demonstrating that the broad profiles seen are intrinsic to the line and not broad due to instrumental issues. However, we do find that when fitting with a Gaussian line profile, the width of the Gaussian can depend on the continuum model in instruments with low spectral resolution, though when the different models fit equally well the line widths generally agree. We also demonstrate that three BeppoSAX observations show evidence for asymmetric lines, with a relativistic diskline model providing a significantly better fit than a Gaussian. We test this by using the posterior predictive p-value method, and bootstrapping of the spectra to show that such deviations from a Gaussian are unlikely to be observed by chance.

Cackett, Edward M. [Department of Physics and Astronomy, Wayne State University, 666 W. Hancock St, Detroit, MI 48201 (United States); Miller, Jon M. [Department of Astronomy, University of Michigan, 500 Church St, Ann Arbor, MI 48109-1042 (United States); Reis, Rubens C.; Fabian, Andrew C. [Institute of Astronomy, University of Cambridge, Madingley Rd, Cambridge, CB3 0HA (United Kingdom); Barret, Didier, E-mail: ecackett@wayne.edu [Institut de Recherche en Astrophysique et Planetologie, 9, Avenue du Colonel Roche, BP 44346, F-31028 Toulouse Cedex 4 (France)

2012-08-10T23:59:59.000Z

45

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  

Science Conference Proceedings (OSTI)

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.

Fix, N. J.

2008-01-31T23:59:59.000Z

46

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

E-Print Network (OSTI)

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.

Shin-ichiro Fujimoto; Ryuichi Matsuba; Kenzo Arai

2007-10-10T23:59:59.000Z

47

Mass Models and Sunyaev-Zeldovich Effect Predictions for a Flux Limited Sample of 22 Nearby X-Ray Clusters  

E-Print Network (OSTI)

We define a 90% complete, volume-limited sample of 31 z<0.1 x-ray clusters and present a systematic analysis of public ROSAT PSPC data on 22 of these objects. Our efforts are undertaken in support of the Penn/OVRO SZE survey, and to this end we present predictions for the inverse Compton optical depth towards all 22 of these clusters. We have performed detailed Monte Carlo simulations to understand the effects of the cluster profile uncertainties on the SZE predictions given the OVRO 5.5-meter telescope beam and switching patterns; we find that the profile uncertainties are one of the least significant components of our error budget for SZE-based distance measurements. We also present baryonic masses and baryon mass fractions derived under the assumption of hydrostatic equilibrium for these 22 clusters. The mean baryonic mass fraction within R_500 \\sim 500 h^-1 kpc is (7.02 \\pm 0.28) x 10^-2 h^-3/2, or (19.8 \\pm 0.8) x 10^-2 for h=0.5. We confirm the Allen et al. (1993) claim of an excess absorbing column density towards Abell 478, but do not find similar anomalies in the other 21 clusters in our sample. We also find some evidence for an excess of soft counts in the ROSAT PSPC data. A measurement of H_o using these models and OVRO SZE determinations will be presented in a second paper.

Brian S. Mason; Steven T. Myers

1999-10-25T23:59:59.000Z

48

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

E-Print Network (OSTI)

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.

Jason Pruet; Rebecca Surman; Gail C. McLaughlin

2003-09-24T23:59:59.000Z

49

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

SciTech Connect

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.

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)

2011-09-20T23:59:59.000Z

50

ROSSI X-RAY TIMING EXPLORER OBSERVATIONS OF THE LOW-MASS X-RAY BINARY 4U 1608-522 IN THE UPPER-BANANA STATE  

SciTech Connect

To investigate the physics of mass accretion onto weakly magnetized neutron stars (NSs), 95 archival Rossi X-Ray Timing Explorer data sets of an atoll source 4U 1608-522, acquired over 1996-2004 in the so-called upper-banana state, were analyzed. The object meantime exhibited 3-30 keV luminosity in the range of {approx}< 10{sup 35}-4 x 10{sup 37} erg s{sup -1}, assuming a distance of 3.6 kpc. The 3-30 keV Proportional Counter Array spectra, produced one from each data set, were represented successfully with a combination of a soft and a hard component, the presence of which was revealed in a model-independent manner by studying spectral variations among the observations. The soft component is expressed by the so-called multi-color disk model with a temperature of {approx}1.8 keV, and is attributed to the emission from an optically thick standard accretion disk. The hard component is a blackbody (BB) emission with a temperature of {approx}2.7 keV, thought to be emitted from the NS surface. As the total luminosity increases, a continuous decrease is observed in the ratio of the BB luminosity to that of the disk component. This property suggests that it gradually becomes difficult for the matter flowing through the accretion disk to reach the NS surface, presumably forming outflows driven by the increased radiation pressure. On timescales of hours to days, the overall source variability was found to be controlled by two independent variables: the mass accretion rate and the innermost disk radius, which changes both physically and artificially.

Takahashi, Hiromitsu [Hiroshima Astrophysical Science Center, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Sakurai, Soki; Makishima, Kazuo, E-mail: hirotaka@hep01.hepl.hiroshima-u.ac.jp [Department of Physics, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2011-09-01T23:59:59.000Z

51

AMiBA: SCALING RELATIONS BETWEEN THE INTEGRATED COMPTON-y AND X-RAY-DERIVED TEMPERATURE, MASS, AND LUMINOSITY  

SciTech Connect

We investigate the scaling relations between the X-ray and the thermal Sunyaev-Zel'dovich effect properties of clusters of galaxies, using data taken during 2007 by the Y. T. Lee Array for Microwave Background Anisotropy (AMiBA) at 94 GHz for the six clusters A1689, A1995, A2142, A2163, A2261, and A2390. The scaling relations relate the integrated Compton-y parameter Y {sub 2500} to the X-ray-derived gas temperature T {sub e}, total mass M {sub 2500}, and bolometric luminosity L{sub X} within r {sub 2500}. Our results for the power-law index and normalization are both consistent with the self-similar model and other studies in the literature except for the Y {sub 2500}-L{sub X} relation, for which a physical explanation is given though further investigation may be still needed. Our results not only provide confidence for the AMiBA project but also support our understanding of galaxy clusters.

Huang, Chih-Wei Locutus; Wu, Jiun-Huei Proty; Liao, Yu-Wei; Lin, Kai-Yang; Wang, Fu-Cheng; Chiueh, Tzihong [Department of Physics, Institute of Astrophysics and Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan (China); Ho, Paul T. P.; Koch, Patrick M.; Liu, Guo-Chin; Molnar, Sandor M.; Nishioka, Hiroaki; Altamirano, Pablo; Chang, Chia-Hao; Chang, Shu-Hao; Chang, Su-Wei; Chen, Ming-Tang; Han, Chih-Chiang; Huang, Yau-De [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 10617, Taiwan (China); Umetsu, Keiichi [LeCosPA Center, National Taiwan University, Taipei 10617, Taiwan (China); Birkinshaw, Mark [Department of Physics, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)

2010-06-10T23:59:59.000Z

52

Following the Colour of the Low Mass X-ray Binary 4U 1820-30 with INTEGRAL  

E-Print Network (OSTI)

The 4-200 keV spectral and temporal behaviour of the low mass X-ray binary 4U 1820-30 has been studied with INTEGRAL during 2003-2005. This source as been observed in both the soft (banana) and hard (island) spectral states. A high energy tail above 50 keV in the hard state has been revealed for the first time. This places the source in the category of X-ray bursters showing high-energy emission. The tail can be modeled as a soft power law component, with the photon index of ~ 2.4, on top of thermal Comptonization emission from a plasma with the electron temperature of kT_e ~ 6 keV and optical depth of $\\tau ~ 4. Alternatively, but at a lower goodness of the fit, the hard-state broad band spectrum can be accounted for by emission from a hybrid, thermal-nonthermal, plasma. During the observations, the source spent most of the time in the soft state, as previously reported and the $\\ge$4 keV spectra can be represented by thermal Comptonization with kT_e ~ 3 keV and $\\tau ~ 6-7.

Antonella Tarana; Angela Bazzano; Pietro Ubertini; A. Andrzej Zdziarski; M. Federici

2006-10-11T23:59:59.000Z

53

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

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.

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

2012-03-05T23:59:59.000Z

54

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

Science Conference Proceedings (OSTI)

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.

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

2010-02-01T23:59:59.000Z

55

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

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.

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

2012-03-05T23:59:59.000Z

56

A study of the ultrahigh-energy cosmic ray mass composition with the MACRO and EAS-TOP experiments  

SciTech Connect

Two components of cosmic-ray-induced air showers are measured simultaneously at the Gran Sasso Laboratory: the electromagnetic shower at the ground surface by the EAS-TOP extensive air shower array, and the deep-underground muons by the MACRO experiment. The two independent data sets collected during 96.3 days of simultaneous running are combined, and underground muon multiplicity distributions are obtained for anticoincident events (no surface trigger) and high-energy, coincident events. These categories correspond to ranges in primary energy from about 2 x 10{sup 3} GeV to a few times 10{sup 5} GeV, and from 1.5 x 10{sup 5} GeV to about 10{sup 7} GeV, respectively. The experimental shower size and muon multiplicity distributions, as well as the distribution of mean muon multiplicity as a function of shower size (N{sub mu} - log(N{sub mu}) relation), are compared to the ones obtained with Monte Carlo calculations using various trial compositions as input. This is done in an effort to discriminate between these models of primary cosmic-ray mass composition at and above the `kneel` in the all-particle spectrum, where contradictory experimental evidence exists and where a knowledge of the composition would bear upon possible mechanisms for cosmic-ray acceleration and propagation. Detailed studies of simulated anticoincident event rates uncover problems with generator used, with between 25 and 40% too few high-energy muons created. This, combined with the dependence of absolute event rates on the assumed differential primary energy spectra, hampers the interpretation in terms of composition of underground muon or surface air shower data taken separately. However, the N{sub mu} - log(N{sub e}) relation is independent of the spectra or overall Monte Carlo normalization problems. The simulated N{sub mu} - log (N{sub e}) relation for coincident events is found to be inconsistent with the possibility that the cosmic ray flux becomes proton-dominated at and above the knee.

Coutu, S.

1993-12-31T23:59:59.000Z

57

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

SciTech Connect

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.

Bein, B. M.; Berkebile-Stoiser, S.; Veronig, A. M.; Temmer, M. [Kanzelhoehe Observatory-IGAM, Institute of Physics, University of Graz, Universitaetsplatz 5, A-8010 Graz (Austria); Vrsnak, B. [Hvar Observatory, Faculty of Geodesy, University of Zagreb, Kaciceva 26, HR-10000 Zagreb (Croatia)

2012-08-10T23:59:59.000Z

58

Variable laser attenuator  

DOE Patents (OSTI)

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.

Foltyn, S.R.

1987-05-29T23:59:59.000Z

59

Variable laser attenuator  

SciTech Connect

The disclosure relates to low loss, high power variable attenuators comprng 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.

Foltyn, Stephen R. (Los Alamos, NM)

1988-01-01T23:59:59.000Z

60

XTE J1701-462 AND ITS IMPLICATIONS FOR THE NATURE OF SUBCLASSES IN LOW-MAGNETIC-FIELD NEUTRON STAR LOW-MASS X-RAY BINARIES  

SciTech Connect

We report on an analysis of Rossi X-Ray Timing Explorer data of the transient neutron star low-mass X-ray binary (NS-LMXB) XTE J1701-462, obtained during its 2006-2007 outburst. The X-ray properties of the source changed between those of various types of NS-LMXB subclasses. At high luminosities, the source switched between two types of Z source behavior and at low luminosities we observed a transition from Z source to atoll source behavior. These transitions between subclasses primarily manifest themselves as changes in the shapes of the tracks in X-ray color-color (CD) and hardness-intensity diagrams (HID), but they are accompanied by changes in the kHz quasi-periodic oscillations, broadband variability, burst behavior, and/or X-ray spectra. We find that for most of the outburst the low-energy X-ray flux is a good parameter to track the gradual evolution of the tracks in CD and HID, allowing us to resolve the evolution of the source in greater detail than before and relate the observed properties to other NS-LMXBs. We further find that during the transition from Z to atoll, characteristic behavior known as the atoll upper banana can equivalently be described as the final stage of a weakening Z source flaring branch, thereby blurring the line between the two subclasses. Our findings strongly suggest that the wide variety in behavior observed in NS-LXMBs with different luminosities can be linked through changes in a single variable parameter, namely the mass accretion rate, without the need for additional differences in the neutron star parameters or viewing angle. We briefly discuss the implications of our findings for the spectral changes observed in NS-LMXBs and suggest that, contrary to what is often assumed, the position along the color-color tracks of Z sources is not determined by the instantaneous mass accretion rate.

Homan, Jeroen; Fridriksson, Joel K.; Remillard, Ronald A.; Lewin, Walter H. G. [MIT Kavli Institute for Astrophysics and Space Research, 70 Vassar Street, Cambridge, MA 02139 (United States); Van der Klis, Michiel; Wijnands, Rudy; Altamirano, Diego [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, Science Park 904, 1098 XH, Amsterdam (Netherlands); Mendez, Mariano [Kapteyn Astronomical Institute, Groningen University, 9700 AV, Groningen (Netherlands); Lin Dacheng [Centre d'Etude Spatiale des Rayonnements, UMR 5187, 9 Av. du Colonel Roche, BP 44346, 31028 Toulouse Cedex 4 (France); Casella, Piergiorgio [School of Physics and Astronomy, University of Southampton, Southampton, Hampshire, SO17 1BJ (United Kingdom); Belloni, Tomaso M., E-mail: jeroen@space.mit.ed [INAF-Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (Italy)

2010-08-10T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
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61

Attenuation Based Remedies  

Energy.gov (U.S. Department of Energy (DOE))

The mission of the Attenuation Based Remedies in the Subsurface Applied Field Research Initiative is to seek holistic solutions to DOE’s groundwater contamination problems that consider not only...

62

Radiofrequency attenuator and method  

SciTech Connect

Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3 C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.

Warner, Benjamin P. (Los Alamos, NM); McCleskey, T. Mark (Los Alamos, NM); Burrell, Anthony K. (Los Alamos, NM); Agrawal, Anoop (Tucson, AZ); Hall, Simon B. (Palmerston North, NZ)

2009-11-10T23:59:59.000Z

63

Radiofrequency attenuator and method  

DOE Patents (OSTI)

Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.

Warner, Benjamin P. (Los Alamos, NM); McCleskey, T. Mark (Los Alamos, NM); Burrell, Anthony K. (Los Alamos, NM); Agrawal, Anoop (Tucson, AZ); Hall, Simon B. (Palmerston North, NZ)

2009-01-20T23:59:59.000Z

64

On the possibility to discriminate the mass of the primary cosmic ray using the muon arrival times from extensive air showers: Application for Pierre Auger Observatory  

SciTech Connect

In this paper we study the possibility to discriminate the mass of the primary cosmic ray by observing the muon arrival times in ground detectors. We analyzed extensive air showers (EAS) induced by proton and iron nuclei with the same energy 8 Multiplication-Sign 10{sup 17} eV simulated with CORSIKA, and analyzed the muon arrival times at ground measured by the infill array detectors of the Pierre Auger Observatory (PAO). From the arrival times of the core and of the muons the atmospheric depth of muon generation locus is evaluated. The results suggest a potential mass discrimination on the basis of muon arrival times and of the reconstructed atmospheric depth of muon production. An analysis of a larger set of CORSIKA simulations carried out for primary energies above 10{sup 18} eV is in progress.

Arsene, N.; Rebel, H.; Sima, O. [Institute of Space Science (ISS), Bucharest-Magurele, P.O. Box MG-23 (Romania) and Physics Department, University of Bucharest, Bucharest-Magurele (Romania); Karlsruhe Institute of Technology, Karlsruhe (Germany); Physics Department, University of Bucharest, Bucharest-Magurele (Romania)

2012-11-20T23:59:59.000Z

65

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

E-Print Network (OSTI)

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.

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

2011-05-09T23:59:59.000Z

66

LINE-ABOVE-GROUND ATTENUATOR  

DOE Patents (OSTI)

The line-above-ground attenuator provides a continuously variable microwave attenuator for a coaxial line that is capable of high attenuation and low insertion loss. The device consists of a short section of the line-above- ground plane type transmission lime, a pair of identical rectangular slabs of lossy material like polytron, whose longitudinal axes are parallel to and indentically spaced away from either side of the line, and a geared mechanism to adjust amd maintain this spaced relationship. This device permits optimum fineness and accuracy of attenuator control which heretofore has been difficult to achieve.

Wilds, R.B.; Ames, J.R.

1957-09-24T23:59:59.000Z

67

Measurement of {sup 63}Ni and {sup 59}Ni by accelerator mass spectrometry using characteristic projectile x-rays  

SciTech Connect

The long-lived isotopes of nickel ({sup 59}Ni, {sup 63}Ni) have current and potential use in a number of applications including cosmic radiation studies, biomedical tracing, characterization of low-level radioactive wastes, and neutron dosimetry. Methods are being developed at LLNL for the routine detection of these isotopes by AMS. One intended application is in Hiroshima dosimetry. The reaction {sup 63}Cu(n,p){sup 63}Ni has been identified as one of a small number of reactions which might be used for the direct determination of the fast neutron fluence emitted by the Hiroshima bomb. AMS measurement of {sup 63}Ni(t{sub 1/2} = 100 y) requires the chemical removal of {sup 63}Cu, which is a stable isobar of {sup 63}Ni. Following the electrochemical separation of Ni from gram-sized copper samples, the Cu concentration is further lowered to < 2 x 10{sup -8} (Cu/Ni) using the reaction of Ni with carbon monoxide to form the gas Ni(CO){sub 4}. The Ni(CO){sub 4} is thermally decomposed directly in sample holders for measurement by AMS. After analysis in the AMS spectrometer, the ions are identified using characteristic projectile x-rays, allowing further rejection of remaining {sup 63}Cu. In a demonstration experiment, {sup 63}Ni was measured in Cu wires (2-20 g) which had been exposed to neutrons from a {sup 252}Cf source. We successfully measured {sup 63}Ni at levels necessary for the measurement of Cu samples exposed near the Hiroshima hypocenter. For the demonstration samples, the Cu content was chemically reduced by a factor of 10{sup 12} with quantitative retention of {sup 63}Ni. Detection sensitivity (3{sigma}) was {approximately}20 fg {sup 63}Ni in 1 mg Ni carrier ({sup 63}Ni/Ni {approx} 2 x 10{sup -11}). Significant improvements in sensitivity are expected with planned incremental changes in the methods. Preliminary results indicate that a similar sensitivity is achievable for {sup 59}Ni (t{sub 1/2} = 10{sup 5} y).

McAninch, J.E.; Hainsworth, L.J.; Marchetti, A.A. [and others

1996-05-01T23:59:59.000Z

68

On the Photon Mass  

E-Print Network (OSTI)

We review the case for the photon having a tiny mass compatible with the experimental limits. We go over some possible experimental tests for such a photon mass including the violation of Lorentz symmetry. We point out that such violations may already have been witnessed in tests involving high energy gamma rays from outer space as also ultra high energy cosmic rays.

Burra G. Sidharth

2007-06-22T23:59:59.000Z

69

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

Science Conference Proceedings (OSTI)

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.

Engel, M. C.; Heinke, C. O.; Sivakoff, G. R.; Elshamouty, K. G. [Physics Department, 4-183 CCIS, University of Alberta, Edmonton, AB T6G 2E1 (Canada); Edmonds, P. D., E-mail: mcengel@ualberta.ca, E-mail: heinke@ualberta.ca [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

2012-03-10T23:59:59.000Z

70

X-ray transmissive debris shield  

DOE Patents (OSTI)

An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

Spielman, R.B.

1996-05-21T23:59:59.000Z

71

X-ray transmissive debris shield  

DOE Patents (OSTI)

An X-ray debris shield for use in X-ray lithography that is comprised of an X-ray window having a layer of low density foam exhibits increased longevity without a substantial increase in exposure time. The low density foam layer serves to absorb the debris emitted from the X-ray source and attenuate the shock to the window so as to reduce the chance of breakage. Because the foam is low density, the X-rays are hardly attenuated by the foam and thus the exposure time is not substantially increased.

Spielman, Rick B. (Albuquerque, NM)

1996-01-01T23:59:59.000Z

72

On the maximum amplitude and coherence of the kilohertz quasi-periodic oscillations in low-mass X-ray binaries  

E-Print Network (OSTI)

I study the behaviour of the maximum rms fractional amplitude, $r_{\\rm max}$ and the maximum coherence, $Q_{\\rm max}$, of the kilohertz quasi-periodic oscillations (kHz QPOs) in a dozen low-mass X-ray binaries. I find that: (i) The maximum rms amplitudes of the lower and the upper kHz QPO, $r^{\\ell}_{\\rm max}$ and $r^{\\rm u}_{\\rm max}$, respectively, decrease more or less exponentially with increasing luminosity of the source; (ii) the maximum coherence of the lower kHz QPO, $Q^{\\ell}_{\\rm max}$, first increases and then decreases exponentially with luminosity, at a faster rate than both $r^{\\ell}_{\\rm max}$ and $r^{\\rm u}_{\\rm max}$; (iii) the maximum coherence of the upper kHz QPO, $Q^{\\rm u}_{\\rm max}$, is more or less independent of luminosity; and (iv) $r_{\\rm max}$ and $Q_{\\rm max}$ show the opposite behaviour with hardness of the source, consistent with the fact that there is a general anticorrelation between luminosity and spectral hardness in these sources. Both $r_{\\rm max}$ and $Q_{\\rm max}$ in the sample of sources, and the rms amplitude and coherence of the kHz QPOs in individual sources show a similar behaviour with hardness. This similarity argues against the interpretation that the drop of coherence and rms amplitude of the lower kHz QPO at high QPO frequencies in individual sources is a signature of the innermost stable circular orbit around a neutron star. I discuss possible interpretations of these results in terms of the modulation mechanisms that may be responsible for the observed variability.

Mariano Mendez

2006-07-18T23:59:59.000Z

73

Mass composition of 10{sup 17}- to 10{sup 18}-eV primary cosmic rays according to data on the lateral distribution of radio emission from extensive air showers  

SciTech Connect

Experimental data obtained for the lateral distribution of radio emission from extensive air showers (EAS) at the array of Moscow State University (30-34 MHz) and the LOPES array (40-80 MHz) were comparedwith the results of calculations performed within amicroscopic approach based on aMonte Carlo simulation of EAS (CORSIKA code). The same experimental data were used to reconstruct the distribution of the depth of the EAS maximum at cosmic-ray energies in the range of 1017-1018 eV. The energy dependence of the depth of the EAS maximum was constructed for the case of data from the LOPES array, and the mass composition of cosmic rays was estimated for this case. From the resulting dependences, it follows that the mass composition shows a trend toward becoming lighter in the energy range being considered.

Kalmykov, N. N., E-mail: kalm@eas.sinp.msu.ru; Konstantinov, A. A.; Vedeneev, O. V. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

2012-12-15T23:59:59.000Z

74

Atmospheric attenuation of solar radiation  

DOE Green Energy (OSTI)

The attenuation of solar radiation by the atmosphere between the heliostat and receiver of a Central Receiver solar energy system has been computed for a number of atmospheric conditions and tower-heliostat distances. The most important atmospheric variable is found to be the atmospheric aerosol content. No dependence of atmospheric water vapor is found and only a weak dependence on solar zenith angle. For a 500 m heliostat-tower distance two to four percent reductions are expected under typical desert conditions (50 to 120 km visibility). The reduction is approximately linear with heliostat-tower distance. A representative value of the attenuation coefficient is 0.051 km/sup -1/.

Randall, C.M.

1977-05-18T23:59:59.000Z

75

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

Science Conference Proceedings (OSTI)

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.

Krupka, Kenneth M.; Martin, Wayne J.

2001-07-23T23:59:59.000Z

76

ENHANCEMENTS TO NATURAL ATTENUATION: SELECTED CASE STUDIES  

Science Conference Proceedings (OSTI)

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).

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

2007-05-15T23:59:59.000Z

77

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

E-Print Network (OSTI)

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.

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

2011-08-08T23:59:59.000Z

78

A POSSIBLE SIGNATURE OF LENSE-THIRRING PRECESSION IN DIPPING AND ECLIPSING NEUTRON-STAR LOW-MASS X-RAY BINARIES  

Science Conference Proceedings (OSTI)

Relativistic Lense-Thirring precession of a tilted inner accretion disk around a compact object has been proposed as a mechanism for low-frequency ({approx}0.01-70 Hz) quasi-periodic oscillations (QPOs) in the light curves of X-ray binaries. A substantial misalignment angle ({approx}15 Degree-Sign -20 Degree-Sign ) between the inner-disk rotation axis and the compact-object spin axis is required for the effects of this precession to produce observable modulations in the X-ray light curve. A consequence of this misalignment is that in high-inclination X-ray binaries the precessing inner disk will quasi-periodically intercept our line of sight to the compact object. In the case of neutron-star systems, this should have a significant observational effect, since a large fraction of the accretion energy is released on or near the neutron-star surface. In this Letter, I suggest that this specific effect of Lense-Thirring precession may already have been observed as {approx}1 Hz QPOs in several dipping/eclipsing neutron-star X-ray binaries.

Homan, Jeroen, E-mail: jeroen@space.mit.edu [Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 70 Vassar Street, Cambridge, MA 02139 (United States)

2012-12-01T23:59:59.000Z

79

Discovery of Two Types of X-ray Dips in Cyg X-1  

E-Print Network (OSTI)

We observed Cyg X-1 with {\\em RXTE} contiguously over its 5.6-day binary orbit. The source was found to be in the hard state throughout the observation. Many intensity dips were detected in the X-ray light curves. We found that the dips fell into two distinct categories based on their spectral properties. One type exhibits strong energy-dependent attenuation of X-ray emission at low energies during a dip, which is characteristic of photoelectric absorption, but the other type shows nearly energy-independent attenuation. While the first type of dips are likely caused by density enhancement in an inhomogeneous wind of the companion star, as previous studies have indicated, the second type might be due to partial obscuration of an extended X-ray emitting region by optically thick ``clumps'' in the accretion flow. It is also possible that the latter are caused by a momentary decrease in the X-ray luminosity of the source, due, for instance, to a decrease in the mass accretion rate, or by Thomson scattering in highly ionized ``clumps''. We discuss the implications of these scenarios.

Y. X. Feng; Wei Cui

2001-12-06T23:59:59.000Z

80

Enhanced Attenuation Technologies: Passive Soil Vapor Extraction  

SciTech Connect

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.

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

2010-03-15T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Monitored Natural Attenuation of Chlorinated Solvents - Moving Beyond Reuctive Dechlorination  

SciTech Connect

Monitored natural attenuation (MNA), while a remedy of choice for many sites, can be challenging when the contaminants are chlorinated solvents. Even with many high quality technical guidance references available there continue to be challenges implementing MNA at some chlorinated solvent sites. The U.S. Department of Energy, as one organization facing such challenges, is leading a project that will incorporate developing concepts and tools into the existing toolbox for selecting and implementing MNA as a remediation option at sites with chlorinated solvents contamination. The structure and goals of this project were introduced in an article in the Winter 2004 issue of Remediation (Sink et al.). This article is a summary of the three technical areas being developed through the project: mass balance, enhanced attenuation, and characterization and monitoring supporting the first two areas. These topics will be documented in separate reports available from the US Department of Energy Office of Scientific and Technical Information at www.osti.gov.

Vangelas, K

2006-04-10T23:59:59.000Z

82

Calibration of High-Resolution X-Ray Tomography With ...  

Science Conference Proceedings (OSTI)

... The x-ray attenuation of the sample at this energy was close to the ... J. Coal Geol. ... G. Xu, DE Eastman, I. McNulty, SP Frigo, Y. Wang, CC Retsch, IC ...

2001-04-11T23:59:59.000Z

83

ADVANCING THE SCIENCE OF NATURAL AND ENHANCED ATTENUATION FOR CHLORINATED SOLVENTS  

SciTech Connect

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.

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

2006-12-27T23:59:59.000Z

84

Spectral analysis of X-ray binaries  

E-Print Network (OSTI)

In this thesis, I present work from three separate research projects associated with observations of X-ray binaries. Two of those revolve around spectral characteristics of neutron star low-mass X-ray binaries (NS-LMXBs), ...

Fridriksson, Joel Karl

2011-01-01T23:59:59.000Z

85

Development of Quantitative Measurement of Fuel Mass Distribution Using Planar Imaging Technique  

Science Conference Proceedings (OSTI)

The quantified fuel mass distribution of a spray was obtained from laser induced fluorescence images with optical patternation. In the dense spray region, however, the emitted fluorescence signal is significantly attenuated in the path of the detector ... Keywords: Imaging method, Laser induced fluorescence (LIF), Mass distribution, Signal Attenuation, Spray

H. Koh; K. Jung; Y. Yoon; K. Lee; K. -S. Jeong

2006-04-01T23:59:59.000Z

86

Gamma Ray Bursts Sudden, intense flashes of gamma rays  

E-Print Network (OSTI)

. Sakamoto1,12 , C. L. Sarazin13 , P. Schady6,10 , M. Stamatikos1,12 & S. E. Woosley14 Gamma-ray bursts (GRBs. Identification of two classes of gamma-ray bursts. Astrophys. J. 413, L101­L104 (1993). 2. Fruchter, A. et al). 3. Woosley, S. E. Gamma-ray bursts from stellar mass accretion disks around black holes. Astrophys

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

87

EEEL Researchers Develop Novel Attenuator for High-energy ...  

Science Conference Proceedings (OSTI)

EEEL Researchers Develop Novel Attenuator for High-energy Lasers. For Immediate Release: June 2, 2008. ...

2011-10-03T23:59:59.000Z

88

Backscatter-contour-attenuation joint estimation model for attenuation compensation in ultrasound imagery  

Science Conference Proceedings (OSTI)

Ultrasound B-scan exhibits shadowing and enhancement artifacts due to acoustic wave propagation and spatially varying scatter attenuation across layers of tissues. These artifacts hide underlying echo signals that are truly clinically indicative of diseases. ... Keywords: attenuation compensation, backscatter, optimization, shadowing artifact, ultrasound imaging

Yongjian Yu; Jue Wang

2010-10-01T23:59:59.000Z

89

Modeling broadband X-ray absorption of massive star winds  

E-Print Network (OSTI)

We present a method for computing the net transmission of X-rays emitted by shock-heated plasma distributed throughout a partially optically thick stellar wind from a massive star. We find the transmission by an exact integration of the formal solution, assuming the emitting plasma and absorbing plasma are mixed at a constant mass ratio above some minimum radius, below which there is assumed to be no emission. This model is more realistic than either the slab absorption associated with a corona at the base of the wind or the exospheric approximation that assumes all observed X-rays are emitted without attenuation from above the radius of optical depth unity. Our model is implemented in XSPEC as a pre-calculated table that can be coupled to a user-defined table of the wavelength dependent wind opacity. We provide a default wind opacity model that is more representative of real wind opacities than the commonly used neutral ISM tabulation. Preliminary modeling of \\textit{Chandra} grating data indicates that the ...

Leutenegger, Maurice A; Zsargó, Janos; Martell, Erin M; MacArthur, James P; Owocki, Stanley P; Gagné, Marc; Hillier, D John

2010-01-01T23:59:59.000Z

90

Negative mass  

E-Print Network (OSTI)

Some physical aspects of negative mass are examined. Several unusual properties, such as the ability of negative mass to penetrate any armor, are analyzed. Other surprising effects include the bizarre system of negative mass chasing positive pass, naked singularities and the violation of cosmic censorship, wormholes, and quantum mechanical results as well. In addition, a brief look into the implications for strings is given.

Richard T Hammond

2013-08-06T23:59:59.000Z

91

ALPHA ATTENUATION DUE TO DUST LOADING  

SciTech Connect

Previous studies had been done in order to show the attenuation of alpha particles in filter media. These studies provided an accurate correction for this attenuation, but there had not yet been a study with sufficient results to properly correct for attenuation due to dust loading on the filters. At the Savannah River Site, filter samples are corrected for attenuation due to dust loading at 20%. Depending on the facility the filter comes from and the duration of the sampling period, the proper correction factor may vary. The objective of this study was to determine self-absorption curves for each of three counting instruments. Prior work indicated significant decreases in alpha count rate (as much as 38%) due to dust loading, especially on filters from facilities where sampling takes place over long intervals. The alpha count rate decreased because of a decrease in the energy of the alpha. The study performed resulted in a set of alpha absorption curves for each of three detectors. This study also took into account the affects of the geometry differences in the different counting equipment used.

Dailey, A; Dennis Hadlock, D

2007-08-09T23:59:59.000Z

92

Computing the Seismic Attenuation in Complex Porous Materials  

E-Print Network (OSTI)

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

Masson, Yder Jean

2010-01-01T23:59:59.000Z

93

Polarimetric Radar at Attenuated Wavelength as a Hydrological Sensor  

Science Conference Proceedings (OSTI)

A new method for the estimation of the rain rate using a polarimetric radar at attenuated wavelengths is proposed. At attenuated wavelengths, the differential reflectivity for horizontal and vertical polarization, ZDR, is the addition of a term ...

Henri Sauvageot

1996-06-01T23:59:59.000Z

94

Mass Measurements  

Science Conference Proceedings (OSTI)

... NIST maintains the national standard for mass in the form of the prototype kilogram (K20) and provides services to support the parts of the national ...

2013-06-28T23:59:59.000Z

95

fehlende Masse  

NLE Websites -- All DOE Office Websites (Extended Search)

beim radioaktiven Zerfall mit der fehlenden Masse?" Zur Erinnerung: wenn Uran in Thorium und ein alpha Teilchen zerfllt, dann gehen 0.0046 u (Masseneinheiten) der...

96

Applied Field Research Initiative Attenuation Based Remedies  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

PA00133 - March 2011 PA00133 - March 2011 Applied Field Research Initiative Attenuation Based Remedies in the Subsurface Located at the Savannah River Site in Aiken, South Carolina, the Attenuation-Based Remedies in the Subsurface Applied Field Research Initiative (ABRS AFRI) was established to develop the tools, approaches and technologies that will be required to address the technical challenges associated characteriza- tion, remediation and long-term monitoring of recalcitrant compounds in the subsurface at Department of Energy (DOE) Environmental Management (EM) sites. The ABRS AFRI site provides a unique setting for researchers in both applied and basic science fields. A wealth of subsurface data is available to support research activities and remedial decision making.

97

Direct three-dimensional coherently scattered x-ray microtomography  

Science Conference Proceedings (OSTI)

Purpose: It has been shown that coherently scattered x rays can be used to discriminate and identify specific components in a mixture of low atomic weight materials. The authors demonstrated a new method of doing coherently scattered x-ray tomography with a thin sheet of x ray. Methods: A collimated x-ray fan-beam, a parallel polycapillary collimator, and a phantom consisting of several biocompatible materials of low attenuation-based contrast were used to investigate the feasibility of the method. Because of the particular experimental setup, only the phantom translation perpendicular to the x-ray beam is needed and, thus, there is no need of Radon-type tomographic reconstruction, except for the correction of the attenuation to the primary and scattered x rays, which was performed by using a conventional attenuation-based tomographic image data set. The coherent scatter image contrast changes with momentum transfer among component materials in the specimen were investigated with multiple x-ray sources with narrow bandwidth spectra generated with anode and filter combinations of Cu/Ni (8 keV), Mo/Zr (18 keV), and Ag/Pd (22 keV) and at multiple scatter angles by orienting the detector and polycapillary collimator at different angles to the illuminating x ray. Results: The contrast among different materials changes with the x-ray source energy and the angle at which the image was measured. The coherent scatter profiles obtained from the coherent scatter images are consistent with the published results. Conclusions: This method can be used to directly generate the three-dimensional coherent scatter images of small animal, biopsies, or other small objects with low atomic weight biological or similar synthetic materials with low attenuation contrast. With equipment optimized, submillimeter spatial resolution may be achieved.

Cui Congwu; Jorgensen, Steven M.; Eaker, Diane R.; Ritman, Erik L. [Department of Medical Physics, CancerCare Manitoba, 675 McDermot Avenue, Winnipeg, Manitoba R3E 0V9 (Canada); Department of Physiology and Biomedical Engineering, Mayo Clinic, 200 First Street Southwest, Alfred Building 2-409, Rochester, Minnesota 55905 (United States)

2010-12-15T23:59:59.000Z

98

X-ray grid-detector apparatus  

DOE Patents (OSTI)

A hybrid grid-detector apparatus for x-ray systems wherein a microchannel plate structure has an air-interspaced grid portion and a phosphor/optical fluid-filled grid portion. The grids are defined by multiple adjacent channels separated by lead-glass septa. X-rays entering the air-interspaced grid portion at an angle of impingement upon the septa are attenuated, while non-impinging x-rays pass through to the phosphor/fluid filled portion. X-ray energy is converted to luminescent energy in the phosphor/fluid filled portion and the resultant beams of light are directed out of the phosphor/optical fluid filled portion to an imaging device.

Boone, John M. (Folsom, CA); Lane, Stephen M. (Oakland, CA)

1998-01-27T23:59:59.000Z

99

High power radio frequency attenuation device  

DOE Patents (OSTI)

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.

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

1984-01-01T23:59:59.000Z

100

X-ray data booklet. Revision  

SciTech Connect

A compilation of data is presented. Included are properties of the elements, electron binding energies, characteristic x-ray energies, fluorescence yields for K and L shells, Auger energies, energy levels for hydrogen-, helium-, and neonlike ions, scattering factors and mass absorption coefficients, and transmission bands of selected filters. Also included are selected reprints on scattering processes, x-ray sources, optics, x-ray detectors, and synchrotron radiation facilities. (WRF)

Vaughan, D. (ed.)

1986-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

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

102

Anomalous shear wave attenuation in the shallow crust beneath...  

Open Energy Info (EERE)

the Coso volcanic field, and are coincident with the epicentral locations of recent earthquake swarms. No anomalous attenuation is seen beneath the Coso volcanic field above about...

103

Radio-adaptive regimen attenuates features of cellular senescence  

NLE Websites -- All DOE Office Websites (Extended Search)

Radio-Adaptive Regimen Attenuates Features of Cellular Senescence Albert Davalos Lawrence Berkeley National Laboratory Abstract Recent work from several laboratories suggest that...

104

A Shallow Attenuating Anomaly Inside The Ring Fracture Of The...  

Open Energy Info (EERE)

Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Caldera, New Mexico Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Shallow...

105

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

E-Print Network (OSTI)

section imaging of radionuclide distributions in heart,the myocardium ivith radionuclides, Radiology, 125 (1977),attenuation correction in radionuclide computed tomography,

Gullberg, Grant T.

2013-01-01T23:59:59.000Z

106

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

Science Conference Proceedings (OSTI)

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.

Vangelas, K

2006-01-30T23:59:59.000Z

107

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

Science Conference Proceedings (OSTI)

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.

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

2006-08-10T23:59:59.000Z

108

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

E-Print Network (OSTI)

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.

Yuri M. Shtemler; Isaac R. Shreiber

2007-05-20T23:59:59.000Z

109

Seismic imaging for velocity and attenuation structure in geothermal fields  

DOE Green Energy (OSTI)

We have applied the attenuation inversion technique developed by Evans and Zucca (1988) to a seismic tomographic data set taken at Newberry Volcano by Achauer et al. (1988). Our preliminary results suggest that the interpretation of the velocity data by Achauer et al. that a magma chamber is present 3 km beneath the caldera is not confirmed by the attenuation data.

Zucca, J.J. (Lawrence Livermore National Lab., CA (USA)); Evans, J.R. (Geological Survey, Menlo Park, CA (USA))

1989-06-01T23:59:59.000Z

110

Polarimetric Attenuation Correction in Heavy Rain at C Band  

Science Conference Proceedings (OSTI)

The ability of C-band polarimetric radar to account for strong attenuation/differential attenuation is demonstrated in two cases of heavy rain that occurred in the Chicago, Illinois, metropolitan area on 5 August 2008 and in central Oklahoma on ...

Ji-Young Gu; A. Ryzhkov; P. Zhang; P. Neilley; M. Knight; B. Wolf; Dong-In Lee

2011-01-01T23:59:59.000Z

111

Mass Finishing  

Science Conference Proceedings (OSTI)

Table 8 Operating conditions for mass finishing...Brass screw-machine parts Aluminum oxide or granite 6.4-19 0.25-0.75 [MathExpression] -6 Light matte or bright Light cutting (a) Brass stampings or screws (b) Limestone 3.2-13 0.13-0.50 2-6 Bright (a) Submerged tumbling is used for fragile and precision parts. (b) Screw-machine parts...

112

Neutrinos from Gamma Ray Bursts  

E-Print Network (OSTI)

We show that the detection of neutrinos from a typical gamma ray burst requires a kilometer-scale detector. We argue that large bursts should be visible with the neutrino telescopes under construction. We emphasize the 3 techniques by which neutrino telescopes can perform this search: by triggering on i) bursts of muons from muon neutrinos, ii) muons from air cascades initiated by high energy gamma rays and iii) showers made by relatively low energy ($\\simeq 100\\,\\mev$) electron neutrinos. Timing of neutrino-photon coincidences may yield a measurement of the neutrino mass to order $10^{-5}$~eV, an interesting range in light of the solar neutrino anomaly.

F. Halzen; G. Jaczko

1996-02-07T23:59:59.000Z

113

Comparison of Advanced Radar Polarimetric Techniques for Operational Attenuation Correction at C Band  

Science Conference Proceedings (OSTI)

Rain path attenuation correction is a challenging task for quantitative use of weather radar measurements at frequencies higher than S band. The proportionality relationship between specific attenuation ?hh (specific differential attenuation ?dp) ...

Gianfranco Vulpiani; Pierre Tabary; Jacques Parent du Chatelet; Frank S. Marzano

2008-07-01T23:59:59.000Z

114

Microsoft Word - S05418_NatEnhAttenuation.doc  

Office of Legacy Management (LM)

Natural and Enhanced Attenuation Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site 2008 Pilot Study Status Report August 2009 LMS/MON/S05418 This page intentionally left blank LMS/MON/S05418 Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site 2008 Pilot Study Status Report August 2009 This page intentionally left blank U.S. Department of Energy 2008 Pilot Study Status Report August 2009 Doc. No. S05418 Page iii Contents Abbreviations.......................................................................................................................... vii Executive Summary.................................................................................................................

115

Structural Steel Attenuation of External Magnetic Fields in Buildings  

Science Conference Proceedings (OSTI)

This report investigates the passive attenuation of external power-frequency magnetic fields caused by structural steel members used in commercial building construction. This effect has not been considered in previous assessments of the field levels inside buildings.

2007-04-26T23:59:59.000Z

116

A Rain-Rate Retrieval Algorithm for Attenuated Radar Measurements  

Science Conference Proceedings (OSTI)

A dynamic regularization scheme for rain-rate retrievals from attenuated radar measurements is presented. Most regularization techniques, including the optimal estimation method, use the state-space parameters to regularize the problem, which ...

Prabhat K. Koner; Alessandro Battaglia; Clemens Simmer

2010-03-01T23:59:59.000Z

117

Degradation of Radar Reflectivity by Cloud Attenuation at Microwave Frequency  

Science Conference Proceedings (OSTI)

The main object of this paper is to emphasize that clouds—the nonprecipitating component of condensed atmospheric water—can produce a strong attenuation at operational microwave frequencies, although they present a low reflectivity preventing ...

Olivier Pujol; Jean-François Georgis; Laurent Féral; Henri Sauvageot

2007-04-01T23:59:59.000Z

118

Tomographic Reconstruction of Rainfall Fields through Microwave Attenuation Measurements  

Science Conference Proceedings (OSTI)

A new method is presented for estimating the space-time rainfall intensity distribution at ground level over a limited area. This is based on a tomographic technique that exploits the relationship between microwave attenuation and rainfall ...

D. Giuli; A. Toccafondi; G. Biffi Gentili; A. Freni

1991-09-01T23:59:59.000Z

119

SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY: COMPENSATION FOR CONSTANT ATTENUATION  

E-Print Network (OSTI)

V. VI, VII. VII L INTRODUCTION THE MODIFIED PROJECTIONS THEATTENUATED BACK-PROJECTION OPERATOR THE FILTER FUNCTION AND= 0.25, 0.50, 1.00, 3.50 projection bin widths; attenuation

Gullberg, Grant T.

2013-01-01T23:59:59.000Z

120

ORNL system for measurement of telephone-line attenuation  

SciTech Connect

The purpose of modifying the TS-100 Automated Tempest Test System software was to use the equipment for making radio-frequency attenuation measurements between an input port and an output port of a telephone network. One set of tests was performed to simulate the electromagnetic radiation from a secure computer terminal and its coupling to telephone lines within a building. Another set of tests was conducted to determine the procedures for measuring attenuation on telephone lines between buildings that are all within the secure zone. The measurements indicate that attenuation between the terminal and the telephone is a function of many variables; however, attenuation in the cable between the buildings is proportional to the length of the cable between the buildings. 1 ref., 2 figs.

Rochelle, R.W.; Williams, I.E.

1988-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Attenuation of single event induced pulses in CMOS combinational logic  

Science Conference Proceedings (OSTI)

Results are presented of a study of SEU generated transient pulse attenuation in combinational logic structures built using common digital CMOS design practices. SPICE circuit analysis, heavy ion tests, and pulsed, focused laser simulations were used to examine the response characteristics of transient pulse behavior in long logic strings. Results show that while there is an observable effect, it cannot be generally assumed that attenuation will significantly reduce observed circuit bit error rates.

Baze, M.P. [Boeing Defense and Space Group, Seattle, WA (United States)] [Boeing Defense and Space Group, Seattle, WA (United States); Buchner, S.P. [SFA Inc., Landover, MD (United States)] [SFA Inc., Landover, MD (United States)

1997-12-01T23:59:59.000Z

122

First lower limits on the photon-axion-like particle coupling from very high energy gamma-ray observation  

E-Print Network (OSTI)

The intrinsic flux of very high energy (VHE, Energy > 100 GeV) gamma-rays from extragalactic sources is attenuated due to pair production in the interaction with photons of the extragalactic background light (EBL). Depending on the distance of the source, the Universe should be opaque to VHE photons above a certain energy. However, indications exist that the Universe is more transparent than previously thought. A recent statistical analysis of a large sample of VHE spectra shows that the correction for absorption with current EBL models is too strong for the data points with the highest attenuation. An explanation might be the oscillation of VHE photons into hypothetical axion-like particles (ALPs) in ambient magnetic fields. This mechanism would decrease the opacity as ALPs propagate unimpeded over cosmological distances. Here, a large sample of VHE gamma-ray spectra obtained with imaging air Cherenkov telescopes is used to set, for the first time, lower limits on the photon-ALP coupling constant over a large range of ALP masses. The conversion in different magnetic field configurations, including intra-cluster and intergalactic magnetic fields together with the magnetic field of the Milky Way, is investigated taking into account the energy dependence of the oscillations. For optimistic scenarios of the intervening magnetic fields, a lower limit on the photon-ALP coupling of the order of $10^{-12}\\mathrm{GeV}^{-1}$ is obtained whereas more conservative model assumptions result in $2\\times10^{-11}\\mathrm{GeV}^{-1}$. The latter value is within reach of future dedicated ALP searches.

Manuel Meyer; Dieter Horns; Martin Raue

2013-02-05T23:59:59.000Z

123

Unidentified Gamma-Ray Sources and Microquasars  

E-Print Network (OSTI)

Some phenomenological properties of the unidentified EGRET detections suggest that there are two distinct groups of galactic gamma-ray sources that might be associated with compact objects endowed with relativistic jets. We discuss different models for gamma-ray production in both microquasars with low- and high-mass stellar companions. We conclude that the parent population of low-latitude and halo variable sources might be formed by yet undetected microquasars and microblazars.

G. E. Romero; I. A Grenier; M. M. Kaufman Bernado; I. F. Mirabel; D. F. Torres

2004-02-12T23:59:59.000Z

124

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

SciTech Connect

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.

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)

2012-03-13T23:59:59.000Z

125

X-RAY EMISSION FROM THE DOUBLE-BINARY OB-STAR SYSTEM QZ CAR (HD 93206)  

Science Conference Proceedings (OSTI)

X-ray observations of the double-binary OB-star system QZ Car (HD 93206) obtained with the Chandra X-ray Observatory over a period of roughly 2 years are presented. The respective orbits of systems A (O9.7 I+b2 v, P{sub A} = 21 days) and B (O8 III+o9 v, P{sub B} = 6 days) are reasonably well sampled by the observations, allowing the origin of the X-ray emission to be examined in detail. The X-ray spectra can be well fitted by an attenuated three-temperature thermal plasma model, characterized by cool, moderate, and hot plasma components at kT {approx_equal} 0.2, 0.7, and 2 keV, respectively, and a circumstellar absorption of {approx_equal}0.2 x 10{sup 22} cm{sup -2}. Although the hot plasma component could be indicating the presence of wind-wind collision shocks in the system, the model fluxes calculated from spectral fits, with an average value of {approx_equal}7 x 10{sup -13} erg s{sup -1} cm{sup -2}, do not show a clear correlation with the orbits of the two constituent binaries. A semi-analytical model of QZ Car reveals that a stable momentum balance may not be established in either system A or B. Yet, despite this, system B is expected to produce an observed X-ray flux well in excess of the observations. If one considers the wind of the O8 III star to be disrupted by mass transfer, the model and observations are in far better agreement, which lends support to the previous suggestion of mass transfer in the O8 III + o9 v binary. We conclude that the X-ray emission from QZ Car can be reasonably well accounted for by a combination of contributions mainly from the single stars and the mutual wind-wind collision between systems A and B.

Parkin, E. R.; Naze, Y.; Rauw, G. [Institut d'Astrophysique et de Geophysique, Universite de Liege, 17, Allee du 6 Aout, B5c, B-4000 Sart Tilman (Belgium); Broos, P. S.; Townsley, L. K. [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Laboratory, University Park, PA 16802 (United States); Pittard, J. M. [School of Physics and Astronomy, University of Leeds, Woodhouse Lane, Leeds LS2 9JT (United Kingdom); Moffat, A. F. J. [Departement de Physique, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, QC H3C 3J7 (Canada); Oskinova, L. M. [Institute for Physics and Astronomy, University of Potsdam, 14476 Potsdam (Germany); Waldron, W. L., E-mail: parkin@mso.anu.edu.au [Eureka Scientific Inc., 2452 Delmer Street, Oakland, CA 94602 (United States)

2011-05-01T23:59:59.000Z

126

Refractive Optics for Hard X-ray Transmission Microscopy  

Science Conference Proceedings (OSTI)

For hard x-ray transmission microscopy at photon energies higher than 15 keV we design refractive condenser and imaging elements to be used with synchrotron light sources as well as with x-ray tube sources. The condenser lenses are optimized for low x-ray attenuation--resulting in apertures greater than 1 mm--and homogeneous intensity distribution on the detector plane, whereas the imaging enables high-resolution (condenser and imaging lenses are being developed. The imaging lenses (compound refractive lenses, CRLs) are made of SU-8 negative resist by deep x-ray lithography. SU-8 shows high radiation stability. The fabrication technique enables high-quality lens structures regarding surface roughness and arrangement precision with arbitrary 2D geometry. To provide point foci, crossed pairs of lenses are used. Condenser lenses have been made utilizing deep x-ray lithographic patterning of thick SU-8 layers, too, whereas in this case, the aperture is limited due to process restrictions. Thus, in terms of large apertures, condenser lenses made of structured and rolled polyimide film are more attractive. Both condenser types, x-ray mosaic lenses and rolled x-ray prism lenses (RXPLs), are considered to be implemented into a microscope setup. The x-ray optical elements mentioned above are characterized with synchrotron radiation and x-ray laboratory sources, respectively.

Simon, M.; Last, A.; Mohr, J.; Nazmov, V.; Reznikova, E. [Institute for Microstructure Technology, Karlsruhe Institute of Technology Kaiserstrasse 12, 76131 Karlsruhe (Germany); Ahrens, G.; Voigt, A. [Microresist Technology, Koepenikerstrasse 325, 12555 Berlin (Germany)

2011-09-09T23:59:59.000Z

127

Dynamic ray tracing and traveltime corrections for global seismic tomography  

Science Conference Proceedings (OSTI)

We present a dynamic ray tracing program for a spherically symmetric Earth that may be used to compute Frechet kernels for traveltime and amplitude anomalies at finite frequency. The program works for arbitrarily defined phases and background models. The numerical precisions of kinematic and dynamic ray tracing are optimized to produce traveltime errors under 0.1 s, which is well below the data uncertainty in global seismology. This tolerance level is obtained for an integration step size of about 20 km for the most common seismic phases. We also give software to compute ellipticity, crustal and topographic corrections and attenuation.

Tian Yue [Department of Geosciences, Guyot Hall, Princeton University, NJ 08544 (United States)], E-mail: ytian@princeton.edu; Hung, S.-H. [Department of Geosciences, National Taiwan University, Taipei 106, Taiwan (China); Nolet, Guust [Department of Geosciences, Guyot Hall, Princeton University, NJ 08544 (United States); Montelli, Raffaella [ExxonMobil Upstream Research Company, P.O. Box 22189, GW03-940A, Houston, TX 77252-2189 (United States); Dahlen, F.A. [Department of Geosciences, Guyot Hall, Princeton University, NJ 08544 (United States)

2007-09-10T23:59:59.000Z

128

Cooled window for X-rays or charged particles  

DOE Patents (OSTI)

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.

Logan, C.M.

1996-04-16T23:59:59.000Z

129

Cooled window for X-rays or charged particles  

DOE Patents (OSTI)

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.

Logan, Clinton M. (Pleasanton, CA)

1996-01-01T23:59:59.000Z

130

X-Ray Topography  

Science Conference Proceedings (OSTI)

Sep 17, 2009 ... Stress Mapping Analysis by Ray Tracing (SMART): A New Technique ... technique of synchrotron X-ray topography, where a grid made out of ...

131

Seismic Velocity And Attenuation Structure Of The Geysers Geothermal Field,  

Open Energy Info (EERE)

Velocity And Attenuation Structure Of The Geysers Geothermal Field, Velocity And Attenuation Structure Of The Geysers Geothermal Field, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Seismic Velocity And Attenuation Structure Of The Geysers Geothermal Field, California Details Activities (1) Areas (1) Regions (0) Abstract: The Geysers geothermal field is located in northern California and is one of the world's largest producers of electricity from geothermal energy. A key resource management issue at this field is the distribution of fluid in the matrix of the reservoir rock. In this paper, we interpret seismic compressional-wave velocity and quality quotient (Q) data at The Geysers in terms of the geologic structure and fluid saturation in the reservoir. Our data consist of waveforms from approximately 300

132

Ross Ice Shelf in situ radio-frequency ice attenuation  

E-Print Network (OSTI)

We have measured the in situ average electric field attenuation length for radio-frequency signals broadcast vertically through the Ross Ice Shelf. We chose a location, Moore Embayment, south of Minna Bluff, known for its high reflectivity at the ice-sea interface. We confirmed specular reflection and used the return pulses to measure the average attenuation length from 75-1250 MHz over the round-trip distance of 1155 m. We find the average electric field attenuation length to vary from 500 m at 75 MHz to 300 m at 1250 MHz, with an experimental uncertainty of 55 to 15 m. We discuss the implications for neutrino telescopes that use the radio technique and include the Ross Ice Shelf as part of their sensitive volume.

Taylor Barrella; Steven Barwick; David Saltzberg

2010-11-02T23:59:59.000Z

133

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

DOE Patents (OSTI)

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.

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

1980-01-01T23:59:59.000Z

134

Ray tracing visualization toolkit  

Science Conference Proceedings (OSTI)

The Ray Tracing Visualization Toolkit (rtVTK) is a collection of programming and visualization tools supporting visual analysis of ray-based rendering algorithms. rtVTK leverages layered visualization within the spatial domain of computation, enabling ... Keywords: ray tracing, ray-based rendering, visualization

Christiaan Gribble; Jeremy Fisher; Daniel Eby; Ed Quigley; Gideon Ludwig

2012-03-01T23:59:59.000Z

135

**TITLE** ASP Conference Series, Vol. **VOLUME**, **PUBLICATION YEAR** **EDITORS** X-ray Transients from X-ray Binaries to Gamma Ray Bursts  

E-Print Network (OSTI)

Abstract. We discuss three classes of x-ray transients to highlight three new types of transients found with the Wide Field Cameras onboard BeppoSAX. First there are the transients related to Low Mass X-ray Binaries in outburst, typically lasting weeks to months and reaching luminosities of the Eddington limit for a few solar masses. Recently another subclass of outbursts in such binaries has been discovered, which are an order of magnitude fainter and last shorter than typical hours to days. We discuss whether they constitute a separate subset of x-ray binaries. A second class of x-ray transients are the x-ray bursts. Thermonuclear explosions on a neutron star (type I x-ray bursts) usually last of order minutes or less. We discovered a second type (called super x-ray bursts) with a duration of several hours. They relate to thermonuclear detonations much deeper in the neutron star atmosphere, possibly burning on the nuclear ashes of normal x-ray bursts. The third class are the enigmatic Fast X-ray Transients occurring at all galactic latitudes. We found that the bright ones are of two types only: either nearby coronal sources (lasting hours) or the socalled x-ray flashes (lasting minutes). The new class, the X-ray flashes, may be a new type of cosmic explosion, intermediate between supernovae and gamma ray bursts, or they may be highly redshifted gamma ray bursts. It thus appears that the three classes of x-ray transients each come in two flavors: long and short. 1.

John Heise; Jean In ’t Z

2001-01-01T23:59:59.000Z

136

A viscoelastic representation of wave attenuation in porous media  

Science Conference Proceedings (OSTI)

The theories developed by White and co-workers describe the complex moduli of a medium partially saturated with spherical gas pockets and those of stratified layers composed of two heterogeneous porous media. A generalization to gas patches of arbitrary ... Keywords: Mesoscopic loss, Porous media, Wave attenuation, Zener model

Stefano Picotti; José M. Carcione; J. Germán Rubino; Juan E. Santos; Fabio Cavallini

2010-01-01T23:59:59.000Z

137

Rain Attenuation Prediction Model for Lagos at Millimeter Wave Bands  

Science Conference Proceedings (OSTI)

“Rain Attenuation Prediction Model for Lagos at Millimeter Wave bands” is the subject of this work. Lagos (geog. Lat. 6.350N and Long. 3.20E), is a coastal station in the rain forest area in the South-Western Nigeria with an altitude of 380 ...

Abayomi Isiaka Yussuff; Nor Hisham Haji Khamis

138

NETL: Utilization Projects - Speciation and Attenuation of Arsenic and  

NLE Websites -- All DOE Office Websites (Extended Search)

Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities The overall objective of this project is to evaluate the impact of key constituents captured from power plant air streams (arsenic, selenium and mercury) on the disposal and utilization of coal combustion by-products. Specific objectives of the project are: 1) to develop a comprehensive database of field leachate concentrations at a wide range of CCB management sites (about 25 sites), including speciation of arsenic and selenium, and low-detection limit analyses for mercury; and 2) to perform detailed evaluations of the release and attenuation of arsenic and selenium species at 3 CCB sites. The fundamental or mechanistic data to reliably model many of the inorganics in CCB leachate are lacking. There is a large degree of uncertainty in the initial leachate concentrations, long-term leaching characteristics of CCBs, and the attenuation coefficients typically used in groundwater transport models. As a result, the model simulations are either highly conservative, or they can be manipulated to obtain almost any desired result. This research project will develop a coherent field leachate database and soil attenuation coefficients for improved modeling and evaluation of the potential for groundwater impacts at CCB management facilities. The work is focused on speciation of four key constituents at CCB sites: arsenic, selenium, chromium, and mercury. The proposed work will help to narrow the uncertainties in the range of values of these critical inputs and improve the accuracy of the modeling results.

139

Comparison of Reg. Guide 1.99 fluence attenuation methods  

SciTech Connect

U.S. Regulatory Guide 1.99 Revision 2 (U.S. Nuclear Regulatory Commission, 1988, 'Radiation Embrittlement of Reactor Vessel Materials,' Regulatory Guide 1.99, Revision 2, Washington, D.C.) provides for the use of two substantially different methods for determining through-wall fluence in nuclear reactor pressure vessels. One method is a generic attenuation curve based on a simplistic exponential decay equation. Partly due to the simplicity of its application, the generic attenuation method is predominantly used for licensing calculations. However, it has a limitation in that at increasing distances away from the core belt-line, it becomes increasingly less accurate because it cannot account for neutron streaming effects in the cavity region surrounding the pressure vessel. The other attenuation method is based on a displacement per atom (dpa) calculation specific to the reactor vessel structure. The dpa method provides a more accurate representation of fluence attenuation through the reactor pressure vessel (RPV) wall at all elevations of the pressure vessel because it does account for neutron streaming in the cavity region. A requirement for using the dpa method, however, is an accurate flux solution through the RPV wall. This requirement has limited the use of traditional transport methods, such as discrete ordinates, that are limited by their treatment of cavity regions (i.e., air) outside the pressure vessel wall. TransWare Enterprises, under the sponsorship of EPRI and BWRVIR has developed an advanced three-dimensional transport methodology capable of producing fully converged flux solutions throughout the entire reactor system, including in the cavity region and primary shield structures. This methodology provides an accurate and reliable determination of through-wall fluence in boiling water reactor (BWR) and pressurized water reactor (PWR) pressure vessels, thus allowing the dpa method to be implemented with high reliability. Using this advanced 3-D methodology, this paper presents comparisons of the generic and dpa attenuation methods at critical locations in both BWR and PWR pressure vessel walls. (author)

Jones, E.N. [TransWare Enterprises Inc., 1565 Mediterranean Dr., Sycamore, IL 60178 (United States)

2011-07-01T23:59:59.000Z

140

Gravitational waves and gamma-ray bursts  

E-Print Network (OSTI)

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.

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

2012-04-18T23:59:59.000Z

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141

Measurment and Interpretation of Seismic Attenuation for Hydrocarbon Exploration  

Science Conference Proceedings (OSTI)

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.

Michael Batzle; Luca Duranti; James Rector; Steve Pride

2007-12-31T23:59:59.000Z

142

Mercury's Protoplanetary Mass  

E-Print Network (OSTI)

Major element fractionation among chondrites has been discussed for decades as ratios relative to Si or Mg. Recently, by expressing ratios relative to Fe, I discovered a new relationship admitting the possibility that ordinary chondrite meteorites are derived from two components, a relatively oxidized and undifferentiated, primitive component and a somewhat differentiated, planetary component, with oxidation state like the highly reduced enstatite chondrites, which I suggested was identical to Mercury's complement of lost elements. Here, on the basis of that relationship, I derive expressions, as a function of the mass of planet Mercury and the mass of its core, to estimate the mass of Mercury's lost elements, the mass of Mercury's alloy and rock protoplanetary core, and the mass of Mercury's gaseous protoplanet. Although Mercury's mass is well known, its core mass is not, being widely believed to be in the range of 70-80 percent of the planet mass. For a core mass of 75 percent, the mass of Mercury's lost elements is about 1.32 times the mass of Mercury, the mass of the alloy and rock protoplanetary core is about 2.32 times the mass of Mercury, and the mass of the gaseous protoplanet of Mercury is about 700 times the mass of Mercury. Circumstantial evidence is presented in support of the supposition that Mercury's lost elements is identical to the planetary component of ordinary chondrite formation.

J. Marvin Herndon

2004-10-01T23:59:59.000Z

143

Polarization mesurements of gamma ray bursts and axion like particles  

E-Print Network (OSTI)

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.

Andre Rubbia; Alexander Sakharov

2008-09-03T23:59:59.000Z

144

CALCULATION OF PULSED KICKER MAGNETIC FIELD ATTENUATION INSIDE BEAM CHAMBERS  

NLE Websites -- All DOE Office Websites (Extended Search)

CALCULATION OF PULSED KICKER MAGNETIC FIELD ATTENUATION CALCULATION OF PULSED KICKER MAGNETIC FIELD ATTENUATION INSIDE BEAM CHAMBERS S. H. Kim January 8, 2001 1. Introduction and Summary The ceramic beam chambers in the sections of the kicker magnets for the beam injection and extraction in the Advanced Photon Source (APS) are made of alumina. The inner surface of the ceramic chamber is coated with a conductive paste. The choice of coating thickness is intended to reduce the shielding of the pulsed kicker magnetic field while containing the electromagnetic fields due to the beam bunches inside the chamber, and minimize the Ohmic heating due to the fields on the chamber [1]. The thin coating generally does not give a uniform surface resistivity for typical dimensions of the ceramic chambers in use. The chamber cross section is a circular or

145

Attenuation structure of Coso geothermal area, California, from wave pulse  

Open Energy Info (EERE)

structure of Coso geothermal area, California, from wave pulse structure of Coso geothermal area, California, from wave pulse widths Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Attenuation structure of Coso geothermal area, California, from wave pulse widths Details Activities (1) Areas (1) Regions (0) Abstract: Pulse width data are used to invert for attenuation structure in the Coso geothermal area, California. The dataset consists of pulse width measurements of 838 microseismic events recorded on a seismic array of 16 downhole stations between August 1993 and March 1994. The quality factor Q correlates well with surface geology and surface heat flow observations. A broad region of low Q (≈ 30 to 37) is located at 0.5 to 1.2 km in depth below Devil's Kitchen, Nicol Prospects, and Coso Hot Springs. A vertical,

146

Attenuation and source properties at the Coso Geothermal Area, California |  

Open Energy Info (EERE)

source properties at the Coso Geothermal Area, California source properties at the Coso Geothermal Area, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Attenuation and source properties at the Coso Geothermal Area, California Details Activities (1) Areas (1) Regions (0) Abstract: We use a multiple-empirical Green's function method to determine source properties of small (M -0.4 to 1.3) earthquakes and P- and S-wave attenuation at the Coso Geothermal Field, California. Source properties of a previously identified set of clustered events from the Coso geothermal region are first analyzed using an empirical Green's function (EGF) method. Stress-drop values of at least 0.5-1 MPa are inferred for all of the events; in many cases, the corner frequency is outside the usable bandwidth, and the stress drop can only be constrained as being higher than

147

Interlaboratory comparison of radiation-induced attenuation in optical fibers  

Science Conference Proceedings (OSTI)

A comparison of the losses induced in step index multimode, graded index multimode and single mode fibers by pulsed radiation exposure has been made among 12 laboratories over a period of 5 years. The recoveries of the incremental attenuations from 10{sup -9} to 10{sup 1} s are reported. Although a standard set of measurement parameters was attempted, differences between the laboratories are evident; possible origins for these are discussed. 18 refs., 18 figs., 7 tabs.

Friebele, E.J.; Lyons, P.B.; Blackburn, J.C.; Henschel, H.; Johan, A.; Krinsky, J.A.; Robinson, A.; Schneider, W.; Smith, D.; Taylor, E.W. (Naval Research Lab., Washington, DC (USA); Los Alamos National Lab., NM (USA); Harry Diamond Labs., Adelphi, MD (USA); Fraunhofer-Institut fuer Naturwissenschaftlich-Technische Trendanalysen (INT), Euskirchen (Germany, F.R.); Direction des Recherches, Etudes et Techni

1989-08-01T23:59:59.000Z

148

Coated x-ray filters  

DOE Patents (OSTI)

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.

Steinmeyer, P.A.

1991-02-07T23:59:59.000Z

149

Coated x-ray filters  

DOE Patents (OSTI)

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.

Steinmeyer, Peter A. (Farmington, NM)

1992-11-24T23:59:59.000Z

150

Cosmic Ray Radiography of the Damaged Cores of the Fukushima Reactors  

E-Print Network (OSTI)

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.

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

2012-09-13T23:59:59.000Z

151

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

Science Conference Proceedings (OSTI)

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}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.

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)

2013-08-20T23:59:59.000Z

152

Determination of Sulfur in Biodiesel and Petroleum Diesel by X-ray Fluorescence (XRF) Using the Gravimetric Standard Addition Method-II †  

E-Print Network (OSTI)

Sulfur in petroleum diesel is typically detected by wavelength dispersive X-ray fluorescence (XRF) spectrometry by comparing the response of the unknown to a linear calibration curve composed of a series of matrix-identical standards. Because biodiesel contains about 11 % oxygen by mass and diesel is oxygen-free, the determination of sulfur in biodiesel using petroleum diesel calibrants is predicted to be biased ?-16% due to oxygen absorptive attenuation of the X-ray signal. A gravimetric standard addition method (SAM) was hypothesized to overcome this bias because it should be matrix-independent. Samples of both petroleum diesel (SRM 2723a and European Reference Material EF674a) and biodiesel (candidate SRM 2773, NREL 52537, and NREL 52533) were analyzed, comparing the traditional calibration curve method to the gravimetric SAM approach. As expected, no significant difference was found between the two methods when measuring sulfur in petroleum diesel. Sulfur determinations in biodiesel with petroleum diesel calibrants were lower by ?19% relative to the gravimetric SAM at the 3, 7, and 12 µg/g levels. It is concluded that XRF using gravimetric SAM yields accurate sulfur measurements in biodiesel samples. In addition, the gravimetric SAM approach is insensitive to differences in the C/H ratio.

Lydia R. Barker; W. Robert Kelly; William F. Guthrie

2008-01-01T23:59:59.000Z

153

Cryogenic detector development at LLNL: ultraviolet x-ray, gamma-ray and biomolecule spectroscopy  

SciTech Connect

We are developing low-temperature detectors for optical, ultraviolet, X-ray, and gamma-ray spectroscopy, and for biomolecular mass spectrometry. We present development work on these detectors and materials analysis and biomolecular mass spectrometry. We have measured thin-film Nb/Al/Al2O3/AlNb superconducting tunnel junction (STJ) X-ray detectors in the 0.2 to 1 keV band with a range of different junction sizes and aluminum film thicknesses. In one case, we have achieved the statistical limit to the energy resolution of 13 eV FWHM at 227 eV with an output count rate of 20,600 cts/s.

Labov, S.E.; Frank, M.; le Grand, J.B. [and others

1997-08-12T23:59:59.000Z

154

Gamma-ray Astronomy  

E-Print Network (OSTI)

The relevance of gamma-ray astronomy to the search for the origin of the galactic and, to a lesser extent, the ultra-high-energy cosmic rays has long been recognised. The current renaissance in the TeV gamma-ray field has resulted in a wealth of new data on galactic and extragalactic particle accelerators, and almost all the new results in this field were presented at the recent International Cosmic Ray Conference (ICRC). Here I summarise the 175 papers submitted on the topic of gamma-ray astronomy to the 30th ICRC in Merida, Mexico in July 2007.

Hinton, Jim

2007-01-01T23:59:59.000Z

155

Gamma-ray Astronomy  

E-Print Network (OSTI)

The relevance of gamma-ray astronomy to the search for the origin of the galactic and, to a lesser extent, the ultra-high-energy cosmic rays has long been recognised. The current renaissance in the TeV gamma-ray field has resulted in a wealth of new data on galactic and extragalactic particle accelerators, and almost all the new results in this field were presented at the recent International Cosmic Ray Conference (ICRC). Here I summarise the 175 papers submitted on the topic of gamma-ray astronomy to the 30th ICRC in Merida, Mexico in July 2007.

Jim Hinton

2007-12-20T23:59:59.000Z

156

Theoretical Mass Spectrometry  

Science Conference Proceedings (OSTI)

... Mass spectrometry is an important technique in analytical chemistry, essential in areas including drug development, criminal ... Facilities/Tools Used: ...

2013-03-19T23:59:59.000Z

157

Elbow mass flow meter  

SciTech Connect

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.

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

1994-01-01T23:59:59.000Z

158

Dynamic effective mass of granular media  

E-Print Network (OSTI)

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.

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

2006-05-29T23:59:59.000Z

159

Delayed Nickel Decay in Gamma Ray Bursts  

E-Print Network (OSTI)

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.

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

2002-05-19T23:59:59.000Z

160

X-ray chemistry in envelopes around young stellar objects  

E-Print Network (OSTI)

We present chemical models of the envelope of a young stellar object (YSO) exposed to a central X-ray source. The models are applied to the massive star-forming region AFGL 2591 for different X-ray fluxes. The total X-ray ionization rate is dominated by the `secondary' ionization rate of H2 resulting from fast electrons. The carbon, sulphur and nitrogen chemistries are discussed. It is found that He+ and H3+ are enhanced and trigger a peculiar chemistry. Several molecular X-ray tracers are found and compared to tracers of the far ultraviolet (FUV) field. Like ultraviolet radiation fields, X-rays enhance simple hydrides, ions and radicals. In contrast to ultraviolet photons, X-rays can penetrate deep into the envelope and affect the chemistry even at large distances from the source. Whereas the FUV enhanced species cover a region of 200-300 AU, the region enhanced by X-rays is >1000 AU. Best-fit models for AFGL 2591 predict an X-ray luminosity LX > 1e+31 ergs/s with a hard X-ray spectrum TX > 3e+07 K. Furthermore, we find LX/Lbol ~ 1e-6. The chemistry of the bulk of the envelope mass is dominated by cosmic-ray induced reactions rather than by X-ray induced ionization for X-ray luminosities LX < 1e+33 ergs/s. The calculated line intensities of HCO+ and HCS+ show that high-J lines are more affected than lower J lines by the presence of X-rays due to their higher critical densities, and that such differences are detectable even with large aperture single-dish telescopes. Future instruments such as Herschel-HIFI or SOFIA will be able to observe X-ray enhanced hydrides whereas the sensitivity and spatial resolution of ALMA is well-suited to measure the size and geometry of the region affected by X-rays.

P. Staeuber; S. D. Doty; E. F. van Dishoeck; A. O. Benz

2005-06-14T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Source attenuating HVAC equipment—Just the facts  

Science Conference Proceedings (OSTI)

Current classroom designs range from NC 63 to NC 25. The ASA/ANSI 12.60 Classroom Standard sets a relatively low background sound requirement for classrooms. Achieving 12.60 levels economically requires the maximum in source sound attenuation. This paper will provide a manufacturer’s perspective on current and low noiseHVAC products and the resulting classroomsound levels. Predictive acoustics software will be used to predict the space sound power level and some indication of equipment cost will be provided in order to assist designers in what is the best approach to low noiseclassroom design.

2004-01-01T23:59:59.000Z

162

High-power radio-frequency attenuation device  

DOE Patents (OSTI)

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.

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

1981-12-30T23:59:59.000Z

163

Gamma-Ray Bursts  

E-Print Network (OSTI)

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.

E. Waxman

2000-04-11T23:59:59.000Z

164

TREATABILITY STUDY FOR EDIBLE OIL DEPLOYMENT FOR ENHANCED CVOC ATTENUATION FOR T-AREA, SAVANNAH RIVER SITE  

SciTech Connect

Groundwater beneath T-Area, a former laboratory and semiworks operation at the Department of Energy (DOE) Savannah River Site (SRS), is contaminated by chlorinated solvents (cVOCs). Since the contamination was detected in the 1980s, the cVOCs at T-Area have been treated by a combination of soil vapor extraction and groundwater pump and treat. The site received approval to temporarily discontinue the active groundwater treatment and implement a treatability study of enhanced attenuation - an engineering and regulatory strategy that has recently been developed by DOE and the Interstate Technology and Regulatory Council (ITRC 2007). Enhanced attenuation uses active engineering solutions to alter the target site in such a way that the contaminant plume will passively stabilize and shrink and to document that the action will be effective, timely, and sustainable. The paradigm recognizes that attenuation remedies are fundamentally based on a mass balance. Thus, long-term plume dynamics can be altered either by reducing the contaminant loading from the source or by increasing the rate of natural attenuation processes within all, or part of, the plume volume. The combination of technologies that emerged for T-Area included: (1) neat (pure) vegetable oil deployment in the deep vadose zone in the former source area, (2) emulsified vegetable oil deployment within the footprint of the groundwater plume, and (3) identification of attenuation mechanisms and rates for the distal portion of the plume. In the first part, neat oil spreads laterally forming a thin layer on the water table to intercept and reduce future cVOC loading (via partitioning) and reduce oxygen inputs (via biostimulation). In the second and third parts, emulsified oil forms active bioremediation reactor zones within the plume footprint to degrade existing groundwater contamination (via reductive dechlorination and/or cometabolism) and stimulates long-term attenuation capacity in the distal plume (via cometabolism). For TArea, the enhanced attenuation development process proved to be a powerful tool in developing a strategy that provides a high degree of performance while minimizing adverse collateral impacts of the remediation (e.g., energy use and wetland damage) and minimizing life-cycle costs. As depicted in Figure 1, Edible oil deployment results in the development of structured geochemical zones and serves to decrease chlorinated compound concentrations in two ways: (1) physical sequestration, which reduces effective aqueous concentration and mobility; and (2) stimulation of anaerobic, abiotic and cometabolic degradation processes. In the central deployment area, contaminant initially partitions into the added oil phase. Biodegradation of the added organic substrate depletes the aquifer of oxygen and other terminal electron acceptors and creates conditions conducive to anaerobic degradation processes. The organic substrate is fermented to produce hydrogen, which is used as an electron donor for anaerobic dechlorination by organisms such as Dehalococcoides. Daughter products leaving the central treatment zone are amenable to aerobic oxidation. Further, the organic compounds leaving the central deployment zone (e.g., methane and propane) stimulate and enhance down gradient aerobic cometabolism which degrades both daughter compounds and several parent cVOCs. Figure 1 depicts TCE concentration reduction processes (labeled in green) along with their corresponding breakdown products in a structured geochemical zone scenario. A consortium of bacteria with the same net effect of Dehalococcoides may be present in the structured geochemical zones leading to the degradation of TCE and daughter products. Figure 2 shows a schematic of the documented cVOC degradation processes in both the anaerobic and aerobic structured geochemical zones. Specific aerobic and anaerobic bacteria and their degradation pathways are also listed in the diagram and have either been confirmed in the field or the laboratory. See references in the bibliography in Section 11.

Riha, B.; Looney, B.; Noonkester, J.; Hyde, W.; Walker, R.

2012-05-15T23:59:59.000Z

165

High Energy Gamma Rays from Protons Hitting Compact Objects  

E-Print Network (OSTI)

In a previous paper the spectrum of positrons produced by matter initially at rest falling onto a massive compact object was calculated. In this paper this calculation is generalized to obtain both the spectrum of in-flight positron annihilation and pi0 decay gamma rays produced when protons with a cosmic ray-like spectrum hit the surface. The resulting pi0 decay gamma ray spectrum reflects the high energy proton energy spectrum, and is largely independent of the mass of the compact object. One notable prediction for all compact objects is a dip in the spectrum below 70 MeV. As applied to the 10^6 solar mass massive compact object near to the center of our galaxy, our theory shows promise for explaining the gamma rays coming from the galactic center as observed by both the Compton satellite and HESS ground based array.

J. Barbieri; G. Chapline

2008-06-09T23:59:59.000Z

166

Does Information Have Mass?  

E-Print Network (OSTI)

Does information have mass? This question has been asked many times and there are many answers even on the Internet, including on Yahoo Answers. Usually the answer is "no". Attempts have been made to assess the physical mass of information by estimating the mass of electrons feeding the power-guzzling computers and devices making up the Internet, the result being around 50 gram. Other efforts to calculate the mass of information have assumed that each electron involved in signal transfer carries one bit of information, which makes the corresponding mass to be about 10^-5 gram. We address the fundamental question of minimum mass related to a bit of information from the angles of quantum physics and special relativity. Our results indicate that there are different answers depending on the physical situation, and sometimes the mass can even be negative. We tend to be skeptical about the earlier mass estimations, mentioned above, because our results indicate that the electron's mass does not play a role in any on...

Kish, Laszlo B

2013-01-01T23:59:59.000Z

167

Nuclear Masses in Astrophysics  

E-Print Network (OSTI)

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.

Christine Weber; Klaus Blaum; Hendrik Schatz

2008-12-09T23:59:59.000Z

168

Mass-Loaded Flows  

E-Print Network (OSTI)

A key process within astronomy is the exchange of mass, momentum, and energy between diffuse plasmas in many types of astronomical sources (including planetary nebulae, wind-blown bubbles, supernova remnants, starburst superwinds, and the intracluster medium) and dense, embedded clouds or clumps. This transfer affects the large scale flows of the diffuse plasmas as well as the evolution of the clumps. I review our current understanding of mass-injection processes, and examine intermediate-scale structure and the global effect of mass-loading on a flow. I then discuss mass-loading in a variety of diffuse sources.

J. M. Pittard

2006-07-13T23:59:59.000Z

169

GPU ray tracing  

Science Conference Proceedings (OSTI)

The NVIDIA® OptiX™ ray tracing engine is a programmable system designed for NVIDIA GPUs and other highly parallel architectures. The OptiX engine builds on the key observation that most ray tracing algorithms can be implemented using a small ...

Steven G. Parker; Heiko Friedrich; David Luebke; Keith Morley; James Bigler; Jared Hoberock; David McAllister; Austin Robison; Andreas Dietrich; Greg Humphreys; Morgan McGuire; Martin Stich

2013-05-01T23:59:59.000Z

170

X-ray beamsplitter  

DOE Patents (OSTI)

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.

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

1989-01-01T23:59:59.000Z

171

Gamma ray detector shield  

DOE Patents (OSTI)

A gamma ray detector shield comprised of a rigid, lead, cylindrical-shaped vessel having upper and lower portions with an pneumatically driven, sliding top assembly. Disposed inside the lead shield is a gamma ray scintillation crystal detector. Access to the gamma detector is through the sliding top assembly.

Ohlinger, R.D.; Humphrey, H.W.

1985-08-26T23:59:59.000Z

172

Gamma Ray Bursts  

E-Print Network (OSTI)

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.

Peter Mészáros

2012-04-09T23:59:59.000Z

173

An iterative three-dimensional electron density imaging algorithm using uncollimated Compton scattered x rays from a polyenergetic primary pencil beam  

Science Conference Proceedings (OSTI)

X-ray film-screen mammography is currently the gold standard for detecting breast cancer. However, one disadvantage is that it projects a three-dimensional (3D) object onto a two-dimensional (2D) image, reducing contrast between small lesions and layers of normal tissue. Another limitation is its reduced sensitivity in women with mammographically dense breasts. Computed tomography (CT) produces a 3D image yet has had a limited role in mammography due to its relatively high dose, low resolution, and low contrast. As a first step towards implementing quantitative 3D mammography, which may improve the ability to detect and specify breast tumors, we have developed an analytical technique that can use Compton scatter to obtain 3D information of an object from a single projection. Imaging material with a pencil beam of polychromatic x rays produces a characteristic scattered photon spectrum at each point on the detector plane. A comparable distribution may be calculated using a known incident x-ray energy spectrum, beam shape, and an initial estimate of the object's 3D mass attenuation and electron density. Our iterative minimization algorithm changes the initially arbitrary electron density voxel matrix to reduce regular differences between the analytically predicted and experimentally measured spectra at each point on the detector plane. The simulated electron density converges to that of the object as the differences are minimized. The reconstruction algorithm has been validated using simulated data produced by the EGSnrc Monte Carlo code system. We applied the imaging algorithm to a cylindrically symmetric breast tissue phantom containing multiple inhomogeneities. A preliminary ROC analysis scores greater than 0.96, which indicate that under the described simplifying conditions, this approach shows promise in identifying and localizing inhomogeneities which simulate 0.5 mm calcifications with an image voxel resolution of 0.25 cm and at a dose comparable to mammography.

Van Uytven, Eric; Pistorius, Stephen; Gordon, Richard [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada) and Medical Physics, CancerCare Manitoba, 675 McDermot Ave., Winnipeg, Manitoba, R3A 1R9 (Canada); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Medical Physics, CancerCare Manitoba, 675 McDermot Ave., Winnipeg, Manitoba R3A 1R9 (Canada) and Department of Radiology, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9 (Canada); Department of Radiology, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9 (Canada) and Department of Electrical and Computer Engineering, University of Manitoba, HSC Room GA216, 820 Sherbrook Street, Winnipeg, Manitoba R3A 1R9 (Canada)

2007-01-15T23:59:59.000Z

174

X-ray generator  

DOE Patents (OSTI)

Apparatus and method for producing coherent secondary x-rays that are controlled as to direction by illuminating a mixture of high z and low z gases with an intense burst of primary x-rays. The primary x-rays are produced with a laser activated plasma, and these x-rays strip off the electrons of the high z atoms in the lasing medium, while the low z atoms retain their electrons. The neutral atoms transfer electrons to highly excited states of the highly striped high z ions giving an inverted population which produces the desired coherent x-rays. In one embodiment, a laser, light beam provides a laser spark that produces the intense burst of coherent x-rays that illuminates the mixture of high z and low z gases, whereby the high z atoms are stripped while the low z ones are not, giving the desired mixture of highly ionized and neutral atoms. To this end, the laser spark is produced by injecting a laser light beam, or a plurality of beams, into a first gas in a cylindrical container having an adjacent second gas layer co-axial therewith, the laser producing a plasma and the intense primary x-rays in the first gas, and the second gas containing the high and low atomic number elements for receiving the primary x-rays, whereupon the secondary x-rays are produced therein by stripping desired ions in a neutral gas and transfer of electrons to highly excited states of the stripped ions from the unionized atoms. Means for magnetically confining and stabilizing the plasma are disclosed for controlling the direction of the x-rays.

Dawson, John M. (Los Angeles, CA)

1976-01-01T23:59:59.000Z

175

Thermal masses in leptogenesis  

E-Print Network (OSTI)

We investigate the validity of using thermal masses in the kinematics of final states in the decay rate of heavy neutrinos in leptogenesis calculations. We find that using thermal masses this way is a reasonable approximation, but corrections arise through quantum statistical distribution functions and leptonic quasiparticles.

Kiessig, Clemens P

2009-01-01T23:59:59.000Z

176

Elbow mass flow meter  

DOE Patents (OSTI)

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.

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

1994-08-16T23:59:59.000Z

177

The origin of mass  

Science Conference Proceedings (OSTI)

The origin of mass is one of the deepest mysteries in science. Neutrons and protons, which account for almost all visible mass in the Universe, emerged from a primordial plasma through a cataclysmic phase transition microseconds after the Big Bang. However, ... Keywords: Gordon Bell Prize categories: scalability and time to solution, SC13 proceedings

Peter Boyle, Michael I. Buchoff, Norman Christ, Taku Izubuchi, Chulwoo Jung, Thomas C. Luu, Robert Mawhinney, Chris Schroeder, Ron Soltz, Pavlos Vranas, Joseph Wasem

2013-11-01T23:59:59.000Z

178

W Transverse Mass  

NLE Websites -- All DOE Office Websites (Extended Search)

Some Data Analysis Some Data Analysis The Tevatron produces millions of collisions each second in CDF and DZero. The detectors have hardware triggers to decide if a collision is "interesting," that is it contains a candidate event for any one of a number studies. Our dataset contains 48,844 candidate events for a W mass study. There are other datasets to study Z mass, top and b quarks, QCD, etc. Why don't all the W decays give exactly the same mass? Are all these candidates really Ws? What if we chose only some of these data. How would our choice effect the value of the transverse mass? Work with your classmates. Test the data to see what you can learn. Help with data analysis. Record the best estimate of the W transverse mass from your data analysis. Explain which data you used and why. Check with your classmates and explain any differences between your estimate and theirs.

179

EBT2 dosimetry of x-rays produced by the electron beam from a Plasma Focus for medical applications  

Science Conference Proceedings (OSTI)

The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for intraoperative radiation therapy applications. A Plasma Focus device is being developed to this aim, to be utilized as an x-ray source. The electron beam is driven to impinge on 50 {mu}m brass foil, where conversion x-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the x-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.

Ceccolini, E.; Mostacci, D.; Sumini, M. [Montecuccolino Nuclear Engineering Laboratory - DIENCA, University of Bologna, via dei Colli 16, I-40136 Bologna (Italy); Rocchi, F. [Montecuccolino Nuclear Engineering Laboratory - DIENCA, University of Bologna, via dei Colli 16, I-40136 Bologna (Italy); UTFISSM-PRONOC, ENEA, via Martiri di Monte Sole 4, I-40129 Bologna (Italy); Tartari, A. [Department of Physics, Ferrara University, via Saragat 1, I-44122 Ferrara (Italy); Mariotti, F. [ENEA, IRP-DOS, via dei Colli 16, I-40136 Bologna (Italy)

2012-09-01T23:59:59.000Z

180

1 UNIDENTIFIED GAMMA-RAY SOURCES AND MICROQUASARS  

E-Print Network (OSTI)

Some phenomenological properties of the unidentified EGRET detections suggest that there are two distinct groups of galactic gamma-ray sources that might be associated with compact objects endowed with relativistic jets. We discuss different models for gamma-ray production in both microquasars with low- and high-mass stellar companions. We conclude that the parent population of low-latitude and halo variable sources might be formed by yet undetected microquasars and microblazars. Key words: Gamma ray sources: unidentified; microquasars; black holes. 1.

G. E. Romero; I. A Grenier; M. M. Kaufman Bernadó; I. F. Mirabel; D. F. Torres

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

MassMass transfer andtransfer and arationstearationste  

E-Print Network (OSTI)

, temperature, T, and energy, E, are scalars and their gradient is a vector dc/dx or arationste scalars diffusion coefficient D; for species A in medium B : D = DAB 4 erföringo dx dc D dt.A dm m Massöve c cSepa dx dc )DD(m th Irreversible Thermodynamics considers Thermo-diffusion 4 erföringo T T Thermo

Zevenhoven, Ron

182

X-Ray Observations of Gamma-Ray Burst Afterglows  

E-Print Network (OSTI)

The discovery by the BeppoSAX satellite of X-ray afterglow emission from the gamma-ray burst which occurred on 28 February 1997 produced a revolution in our knowledge of the gamma-ray burst phenomenon. Along with the discovery of X-ray afterglows, the optical afterglows of gamma-ray bursts were discovered and the distance issue was settled, at least for long $\\gamma$-ray bursts. The 30 year mystery of the gamma-ray burst phenomenon is now on the way to solution. Here I rewiew the observational status of the X-ray afterglow emission, its mean properties (detection rate, continuum spectra, line features, and light curves), and the X-ray constraints on theoretical models of gamma-ray bursters and their progenitors. I also discuss the early onset afterglow emission, the remaining questions, and the role of future X-ray afterglow observations.

Filippo Frontera

2004-06-25T23:59:59.000Z

183

Gamma Radiation & X-Rays  

NLE Websites -- All DOE Office Websites (Extended Search)

Gamma Radiation and X-Rays 1. Gamma radiation and X-rays are electromagnetic radiation like visible light, radio waves, and ultraviolet light. These electromagnetic radiations...

184

Gamma Ray Pulsars: Observations  

E-Print Network (OSTI)

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.

David J. Thompson

2001-01-03T23:59:59.000Z

185

X-ray Lines in Gamma-ray Bursts and Cerenkov Line Mechanism  

E-Print Network (OSTI)

X-ray emission and absorption features are of great importance in our understanding the nature and environment of gamma-ray bursts (GRBs). So far, iron emission lines have been detected in at least four GRB afterglows. In this paper, the observational properties and physical constraints on materials surrounding GRB sources are reviewed, and several classes of theoretical models are also discussed. We will specially concentrate on the Cerenkov line mechanism, in which the broad iron lines are expected, and a small mass of Fe is required to produce the large line luminosity. In addition, our interpretation can favor the recent jet unified model for different classes of gamma-ray bursts with a standard energy reservoir.

Wei Wang

2004-07-30T23:59:59.000Z

186

Use of Batch and Column Methodologies to Assess Utility Waste Leaching and Subsurface Chemical Attenuation  

Science Conference Proceedings (OSTI)

Often, a combination of batch and column methods is used in the laboratory to test wastes for leaching and attenuation potentials. This literature review addresses the strengths and limitations of using these two methods to predict leachate generation and subsequent attenuation at coal combustion waste management sites.

1991-05-13T23:59:59.000Z

187

ALGORITHMS FOR JOINT ESTIMATION OF ATTENUATION AND EMISSION IMAGES IN PET  

E-Print Network (OSTI)

ALGORITHMS FOR JOINT ESTIMATION OF ATTENUATION AND EMISSION IMAGES IN PET Hakan Erdogan IBM TJ information about the at- tenuating medium. To use all the available information, we propose a joint in these two scans, one can derive a joint objective function based on both scans to jointly estimate attenu

Erdogan, Hakan

188

Joint Estimation of Attenuation and Emission Images from PET Scans Hakan Erdogan and Jeffrey A. Fessler  

E-Print Network (OSTI)

Joint Estimation of Attenuation and Emission Images from PET Scans Hakan Erdogan and Jeffrey A information about the attenuating medium. To use all the available information, we propose a joint estimation optimal use of the information in these two scans, one can derive a joint objective function based on both

Erdogan, Hakan

189

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

E-Print Network (OSTI)

-frequency attenuation and moduli estimates using a fiber-optic strainmeter = /(2n), where is the wavelength of light of strain gages, fiber-optic and ultrasonic data. * Not enough light was received at the detector (mirrorsSeismic-frequency attenuation and moduli estimates using a fiber-optic strainmeter Ludmila Adam 1

190

Parameters Affecting Water Hammer Wave Attenuation, Shape by Anton Bergant1  

E-Print Network (OSTI)

(hydroelectric power plant, pumping system) and damage the system components; for example pipe displacementParameters Affecting Water Hammer Wave Attenuation, Shape and Timing by Anton Bergant1 and Arris.s.tijsseling@TUE.nl This paper investigates parameters that may affect water hammer wave attenuation, shape and timing. Possible

Eindhoven, Technische Universiteit

191

Calibration of neutron-yield diagnostics in attenuating and scattering environments  

Science Conference Proceedings (OSTI)

We have performed absolute calibrations of a fusion-neutron-yield copper-activation diagnostic in environments that significantly attenuate and scatter neutrons. We have measured attenuation and scattering effects and have compared the measurements to Monte Carlo simulations using the Monte Carlo N-Particle code. We find that measurements and simulations are consistent within 10%.

Hahn, K. D.; Ruiz, C. L.; Chandler, G. A.; Leeper, R. J.; McWatters, B. R.; Smelser, R. M.; Torres, J. A. [Sandia National Laboratories, Diagnostics and Target Physics, Albuquerque, New Mexico 87111 (United States); Cooper, G. W.; Nelson, A. J. [University of New Mexico, Department of Chemical and Nuclear Engineering, Albuquerque, New Mexico 87131 (United States)

2012-10-15T23:59:59.000Z

192

Frontiers in Cosmic Rays  

E-Print Network (OSTI)

This rapporteur review covers selected results presented in the Parallel Session HEA2 (High Energy Astrophysics 2) of the 10th Marcel Grossmann Meeting on General Relativity, held in Rio de Janeiro, Brazil, July 2003. The subtopics are: ultra high energy cosmic ray anisotropies, the possible connection of these energetic particles with powerful gamma ray bursts, and new exciting scenarios with a strong neutrino-nucleon interaction in the atmosphere.

Luis A. Anchordoqui; Charles D. Dermer; Andreas Ringwald

2004-02-27T23:59:59.000Z

193

Gamma-Ray Bursts  

E-Print Network (OSTI)

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.

P. Meszaros

2006-05-09T23:59:59.000Z

194

Higgs Mass Calculations  

NLE Websites -- All DOE Office Websites (Extended Search)

this sheet now. Help with data analysis Higgs Mass Plot Project Contact: Thomas Jordan - jordant@fnal.gov Web Maintainer: qnet-webmaster@fnal.gov Last Update: August 22,...

195

Cosmic Rays and Gamma Ray Bursts From Microblazars  

E-Print Network (OSTI)

Highly relativistic jets from merger and accretion induced collapse of compact stellar objects, which may produce the cosmological gamma ray bursts (GRBs), are also very efficient and powerful cosmic ray accelerators. The expected luminosity, energy spectrum and chemical composition of cosmic rays from Galactic GRBs, most of which do not point in our direction, can explain the observed properties of Galactic cosmic rays.

Arnon Dar

1998-09-13T23:59:59.000Z

196

Solids mass flow determination  

DOE Patents (OSTI)

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.

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

1981-01-01T23:59:59.000Z

197

W Transverse Mass  

NLE Websites -- All DOE Office Websites (Extended Search)

Transverse Mass Histogram Transverse Mass Histogram Data for 49,844 candidate W events are in an Excel spreadsheet with the following data as shown in the table below: A B C D 1 Run No Event No W TMass GeV/c2 Bins 2 55237 19588 68.71732 3 55237 30799 72.19464 Get the data. Sort the data by ascending mass. Be sure to sort all the data in the first three columns! Make a histogram of the data. Rather than graphing the data as individual points, physicists group the data by mass. They consider the full range of the data and divide it into "bins" of equal range size. A histogram is a graph of the number of events in each bin vs. the bin range. They are looking for a peak in the data where most of the masses fall. This will be the value of the mass as detemined by that dataset, and the width of the distribution is a reflection of the errors in the measurements.

198

Plutonium Isotopic Measurements by Gamma-Ray Spectroscopy  

SciTech Connect

The nondestructive assay of plutonium is important as a safeguard tool in accounting for stategic nuclear material. Several nondestructive assay techniques, e.g., calorimetry and spontaneous fission assay detectors, require a knowledge of plutonium and americium isotopic ratios to convert their raw data to total grams of plutonium. This paper describes a nondestructive technique for calculating plutonium-238, plutonium-240, plutonium-241 and americium-241 relative to plutonium-239 from measured peak areas in the high resolution gamma-ray spectra of solid plutonium samples. Gamma-ray attenuation effects have been minimized by selecting sets of neighboring peaks in the spectrum whose components are due to the different isotopes. Since the detector efficiencies are approximately the same for adjacent peaks, the accuracy of the isotopic ratios are dependent on the half-lives, branching intensities and measured peak areas. The data presented describes the results obtained by analyzing gamma-ray spectra in the energy region from 120 to 700 keV. The majority of the data analyzed was obtained from plutonium material containing 6% plutonium-240. Sample weights varied from 0.25 g to approximately 1.2 kg. The methods have also been applied to plutonium samples containing up to 23% plutonium-240 with weights of 0.25 to 200g. Results obtained by gamma-ray spectroscopy are compared to chemical analyses of aliquots taken from the bulk samples.

Haas, Francis X.; Lemming, John F.

1976-05-01T23:59:59.000Z

199

Bremsstrahlung gamma rays from light Dark Matter  

E-Print Network (OSTI)

We discuss the often-neglected role of bremsstrahlung processes on the interstellar gas in computing indirect signatures of Dark Matter (DM) annihilation in the Galaxy, particularly for light DM candidates in the phenomenologically interesting O(10) GeV mass range. Especially from directions close to the Galactic Plane, the expected gamma-ray spectrum is altered via two effects: directly, by the photons emitted in the bremsstrahlung process on the interstellar gas by energetic electrons which are among the DM annihilation byproducts; indirectly, by the modification of the same electron spectrum, due to the additional energy loss process in the diffusion-loss equation (e.g. the resulting inverse Compton emission is altered). We quantify the importance of the bremsstrahlung emission in the GeV energy range, showing that it is the dominant component of the gamma-ray spectrum for some cases. We also find that, in regions in which bremsstrahlung dominates energy losses, the related gamma-ray emission is only moderately sensitive to possible large variations in the gas density. Still, we stress that, for computing precise spectra in the (sub-)GeV range, it is important to obtain a reliable description of the inner Galaxy gas distribution as well as to compute self-consistently the gamma emission and the solution to the diffusion-loss equation. For example, these are crucial issues to quantify and interpret meaningfully gamma-ray map `residuals' in terms of (light) DM annihilations.

Marco Cirelli; Pasquale D. Serpico; Gabrijela Zaharijas

2013-07-26T23:59:59.000Z

200

Gamma-ray events thunderclouds  

E-Print Network (OSTI)

Andromeda: A mission to determine the gamma-ray burst distance scale F.A. Harrison, W.R. Cook, T was submitted to the STEDI program, and will also be proposed as a NASA Small Explorer. Keywords: bursts, gamma-rays, small missions 1 SCIENTIFIC OBJECTIVES 1.1 Gamma-ray Bursts Gamma-ray bursts GRBs were discovered

California at Berkeley, University of

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

The Effect of Temperature on Attenuation-Correction Schemes in Rain Using Polarization Propagation Differential Phase Shift  

Science Conference Proceedings (OSTI)

Several investigators propose estimating the rates of attenuation using the difference in the phase with increasing distance between horizontally and vertically polarized microwaves. These attenuation estimates can then be used to correct ...

A. R. Jameson

1992-09-01T23:59:59.000Z

202

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

E-Print Network (OSTI)

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 ...

Wetzstein, Gordon

203

Giga-Dalton Mass Spectrometry  

Current techniques to study large bio?molecules using mass spectrometer require fragmentation for the mass?to?charge ratios to be within the working range of the mass spectrometer. Analysis of the data is complex and often requires simulation ...

204

EMSL: Capabilities: Mass Spectrometry Experts  

NLE Websites -- All DOE Office Websites (Extended Search)

Related EMSL User Projects Mass Spectrometry Tools are Applied to all Science Themes Next-Generation Mass Spectrometry Proteomics Research Resource for Integrative Biology...

205

High resolution seismic attenuation tomography at Medicine Lake Volcano, California  

DOE Green Energy (OSTI)

Medicine Lake Volcano, a broad shield volcano about 50km east of Mount Shasta in northern California, produced rhylotic eruptions as recently as 400 years ago. Because of this recent activity it is of considerable interest to producers of geothermal energy. In a joint project sponsored by the Geothermal Research Program of the USGS and the Division of Geothermal and Hydropower Division of the US-DOE, the USGS and LLNL conducted an active seismic experiment designed to explore the area beneath and around the caldera. The experiment of eight explosions detonated in a 50 km radius circle around the volcano recorded on a 11 x 15 km grid of 140 seismographs. The travel time data from the experiment have been inverted for structure and are presented elsewhere in this volume. In this paper we present the results of an inversion for 1/Q structure using t* data in a modified Aki inversion scheme. Although the data are noisy, we find that in general attenuative zones correlate with low velocity zones. In particular, we observe a high 1/Q zone roughly in the center of the caldera at 4 km depth in between two large recent dacite flows. This zone could represent the still molten or partially molten source of the flows.

Zucca, J.J.; Kasameyer, P.W.

1987-07-10T23:59:59.000Z

206

X-ray Diagnostics of Broad Absorption Line Quasar Geometry  

E-Print Network (OSTI)

A new generation of sensitive X-ray measurements are indicating that the existence of X-ray attenuation column densities, $N_{H}>10^{24}\\mathrm{cm}^{-2}$ is quite common amongst broad absorption line quasars (BALQSOs). This is significant to the geometry of the broad absorption line (BAL) outflow. In particular, such an X-ray shield also shields equatorial accretion disk winds from the UV, thereby preventing high velocity equatorial outflows from being launched. By contrast, bipolar winds initiated by continuum radiation pressure from the funnel of a slim accretion disk flare outward (like a trumpet) and offer vastly different absorbing columns to the X-ray and UV emission which are emitted from distinct regions of the disk, $\\sim 6M$ and $\\sim 10M-40M$, respectively (where $M$ is the radius of the black hole). Recent numerical work indicates that it is also possible to launch bipolar outflows from the inner regions of a thin disk. The recent discovery with VLBI that the Galactic analog of a BALQSO, the X-ray binary Circinus X-1 (with high velocity P Cygni X-ray absorption lines) is viewed virtually along the radio jet axis (and therefore along the spin axis of the black hole and the normal to the accretion disk) has rekindled interest in the bipolar models of BALQSOs. We explore this possibility by studying the nearest BAL QSO, MRK 231. High resolution 2-D optical spectroscopy and VLBI mappings of the radio jet axis indicates that the BAL outflow is parallel to the parsec scale radio jet.

Brian Punsly; Sebastian Lipari

2005-03-09T23:59:59.000Z

207

Can Naked Singularities Yield Gamma Ray Bursts?  

E-Print Network (OSTI)

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.

H. M. Antia

1998-07-09T23:59:59.000Z

208

THE DIFFUSE GAMMA-RAY BACKGROUND FROM TYPE Ia SUPERNOVAE  

SciTech Connect

The origin of the diffuse extragalactic gamma-ray background (EGB) has been intensively studied but remains unsettled. Current popular source candidates include unresolved star-forming galaxies, starburst galaxies, and blazars. In this paper, we calculate the EGB contribution from the interactions of cosmic rays accelerated by Type Ia supernovae (SNe), extending earlier work that only included core-collapse SNe. We consider Type Ia events not only in star-forming galaxies, but also in quiescent galaxies that lack star formation. In the case of star-forming galaxies, consistently including Type Ia events makes little change to the star-forming EGB prediction, so long as both SN types have the same cosmic-ray acceleration efficiencies in star-forming galaxies. Thus, our updated EGB estimate continues to show that star-forming galaxies can represent a substantial portion of the signal measured by Fermi. In the case of quiescent galaxies, conversely, we find a wide range of possibilities for the EGB contribution. The dominant uncertainty we investigated comes from the mass in hot gas in these objects, which provides targets for cosmic rays; total gas masses are as yet poorly known, particularly at larger radii. Additionally, the EGB estimation is very sensitive to the cosmic-ray acceleration efficiency and confinement, especially in quiescent galaxies. In the most optimistic allowed scenarios, quiescent galaxies can be an important source of the EGB. In this case, star-forming galaxies and quiescent galaxies together will dominate the EGB and leave little room for other contributions. If other sources, such as blazars, are found to have important contributions to the EGB, then either the gas mass or cosmic-ray content of quiescent galaxies must be significantly lower than in their star-forming counterparts. In any case, improved Fermi EGB measurements will provide important constraints on hot gas and cosmic rays in quiescent galaxies.

Lien, Amy; Fields, Brian D. [Department of Physics, University of Illinois, Urbana, IL 61801 (United States)

2012-03-10T23:59:59.000Z

209

Photon: history, mass, charge  

E-Print Network (OSTI)

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.

L. B. Okun

2006-02-03T23:59:59.000Z

210

Mass and Heat Recovery  

E-Print Network (OSTI)

In the last few years heat recovery was under spot and in air conditioning fields usually we use heat recovery by different types of heat exchangers. The heat exchanging between the exhaust air from the building with the fresh air to the building (air to air heat exchanger). In my papers I use (water to air heat exchanger) as a heat recovery and I use the water as a mass recovery. The source of mass and heat recovery is the condensate water which we were dispose and connect it to the drain lines.

Hindawai, S. M.

2010-01-01T23:59:59.000Z

211

X-ray microtomography  

SciTech Connect

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.

Landis, Eric N., E-mail: landis@maine.edu [Department of Civil and Environmental Engineering, University of Maine, 5711 Boardman Hall, Orono, Maine 04469 (United States); Keane, Denis T., E-mail: dtkeane@northwestern.edu [Department of Materials Science and Engineering, Northwestern University (United States); DND-CAT, Advanced Photon Source, Argonne National Laboratory, Bldg. 432/A002, 9700 S. Cass Ave, Argonne, Illinois 60439 (United States)

2010-12-15T23:59:59.000Z

212

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

DOE Data Explorer (OSTI)

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.

Greenwood, R.E.

213

X-ray evidence for capillary pressure driven flow in preserved core from The Geysers  

DOE Green Energy (OSTI)

Improved understanding of fluid storage and transport mechanisms relevant to The Geysers reservoir is fundamental to efficient and economic long term production of steam. X-ray computed tomographs of core from research borehole SB-15D made within 72 hours of drilling show characteristic x-ray attenuation profiles that can only be explained by imbibition of drilling fluid at reservoir conditions. The shape of the profile is highly diagnostic. Early time scans, when interpreted taking into account independent measurements of pore size distribution, permeabilities and capillary pressures for the rock matrix sampled by SB-15D, are consistent with strong capillary suctions for the recovered rocks. This indirect indication of imbibition under reservoir conditions, along with detailed analysis of x-ray attenuation in recovered core, suggests that water content was low in much of the preserved core. These measurements are part of a series of laboratory experiments monitored by x-ray methods intended to evaluate movement of various fluids to determine the relative importance capillarity, Darcy flow and vapor phase diffusion.

Bonner, B.P.; Roberts, J.J.; Schneberk, D.J.

1997-03-01T23:59:59.000Z

214

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

E-Print Network (OSTI)

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.

Aiichi Iwazaki

1999-08-26T23:59:59.000Z

215

Warm Water Mass Formation  

Science Conference Proceedings (OSTI)

Poleward heat transport by the own implies warm Water mass formation, i.e., the retention by the tropical and subtropical ocean of some of its net radiant heat gain. Under what condition net heat retention becomes comparable to latent heat ...

G. T. Csanady

1984-02-01T23:59:59.000Z

216

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

Science Conference Proceedings (OSTI)

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.

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)

2012-10-10T23:59:59.000Z

217

Velocity and Attenuation Structure of the Geysers Geothermal Field, California  

DOE Green Energy (OSTI)

The Geysers geothermal field is located in northern California and is one of the world's largest producers of electricity from geothermal energy. The resource consists of primarily dry steam which is produced from a low, porosity fractured graywacke. Over the last several years steam pressure at the Geysers has been dropping. Concern over decline of the resource has prompted research to understand its fundamental nature. A key issue is the distribution of fluid in the matrix of the reservoir rock. In this paper we interpret seismic compressional-wave velocity and attenuation data at the Geysers in terms of the geologic structure and fluid saturation in the reservoir. Our data consist of approximately 300 earthquakes that are of magnitude 1.2 and are distributed in depth between sea level and 2.5 km. Using compressional-wave arrival times, we invert for earthquake location, origin time, and velocity along a three-dimensional grid. Using the initial pulse width of the compressional-wave, we invert for the initial pulse width associated with the source, and the one-dimensional Q structure. We find that the velocity structure correlates with known mapped geologic units, including a velocity high that is correlated with a felsite body at depth that is known from drilling. The dry steam reservoir, which is also known from drilling, is mostly correlated with low velocity. The Q increases with depth to the top of the dry steam reservoir and decreases with depth within the reservoir. The decrease of Q with depth probably indicates that the saturation of the matrix of the reservoir rock increases with depth.

Zucca, J. J.; Hutchings, L. J.; Kasameyer, P. W.

1993-01-01T23:59:59.000Z

218

THE ROLE FUNGI AND YEAST IN MONITORED NATURAL ATTENUATION  

SciTech Connect

Fungi and yeast have been characterized as important components in the bioremediation of organic contaminants in soil and water including polyaromatic hydrocarbons (PAHs); however, research into their ability to metabolize these compounds in extreme environments has been limited. In this work forty-three fungi and yeasts were isolated from a PAH-contaminated sludge waste lagoon in Poland. The lagoon was part of a monitored natural attenuation (MNA) study where natural reduction of PAHs and associated toxicity over time in non-disturbed areas of the sludge lagoon indicated MNA activity. The microorganisms were initially isolated on minimal medium containing naphthalene as the sole carbon and energy source. Fungal isolates were then maintained on MEA and identified based on microscopic examination and BIOLOG{reg_sign}. The analysis identified several of the fungal isolates as belonging to the genera Penicillium, Paecilomyces, Aspergillus, and Eupenicillium. Yeasts included Candida parapsilosis and C. fluvialitis. Further microbial characterization revealed that several isolates were capable of rowing on acidified media of pH 4, 3, and 2.5. Over twenty percent of the fungi demonstrated growth as low as pH 2.5. Of the 43 isolates examined, 24 isolates exhibited growth at 5 C. Nine of the fungal isolates exhibiting growth at 5 C were then examined for metabolic activity using a respirometer testing metabolic activity at pH 3. Microcosm studies confirmed the growth of the fungi on PAH contaminated sediment as the sole carbon and energy source with elevated metabolic rates indicating evidence of MNA. Our findings suggest that many of the Poland fungal isolates may be of value in the bioremediation processes in acidic waste sites in northern climates typical of Northern Europe.

Brigmon, R.; Abe, M.; Johnson, B.; Simpson, W.; Mckinsey, P.

2010-01-26T23:59:59.000Z

219

Method for calibrating mass spectrometers  

DOE Patents (OSTI)

A method whereby a mass spectra generated by a mass spectrometer is calibrated by shifting the parameters used by the spectrometer to assign masses to the spectra in a manner which reconciles the signal of ions within the spectra having equal mass but differing charge states, or by reconciling ions having known differences in mass to relative values consistent with those known differences. In this manner, the mass spectrometer is calibrated without the need for standards while allowing the generation of a highly accurate mass spectra by the instrument.

Anderson, Gordon A [Benton City, WA; Brands, Michael D [Richland, WA; Bruce, James E [Schwenksville, PA; Pasa-Tolic, Ljiljana [Richland, WA; Smith, Richard D [Richland, WA

2002-12-24T23:59:59.000Z

220

Natural and Enhanced Attenuation of Soil and Groundwater at the Monument  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Natural and Enhanced Attenuation of Soil and Groundwater at the Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site Paper presented at the Waste Management 2010 Conference. March 7 through March 10, 2010, Phoenix, Arizona. W.J.Waugh, D.E. Miller, S.A. Morris, L.R. Sheader, E.P. Glenn, D. Moore, K.C. Carroll, L. Benally, M. Roanhorse, R.P. Bush Natural and Enhanced Attenuation of Soil and Groundwater at the Monument Valley, Arizona, DOE Legacy Waste Site More Documents & Publications EA-1313: Final Environmental Assessment Applied Science and Technology Task Order Fiscal Year 2009 Year-End Summary Report Applied Science and Technology Task Order Fiscal Year 2008 Year-End Summary

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Anomalous shear wave attenuation in the shallow crust beneath the Coso  

Open Energy Info (EERE)

Anomalous shear wave attenuation in the shallow crust beneath the Coso Anomalous shear wave attenuation in the shallow crust beneath the Coso volcanic region, California Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: Anomalous shear wave attenuation in the shallow crust beneath the Coso volcanic region, California Details Activities (1) Areas (1) Regions (0) Abstract: We use seismograms of local earthquakes to image relative shear wave attenuation structure in the shallow crust beneath the region containing the Coso volcanic-geothermal area of eastern California. SV and P wave amplitudes were measured from vertical component seismograms of earthquakes that occurred in the Coso-southern Sierra Nevada region from July 1983 to 1985. Seismograms of 16 small earthquakes show SV amplitudes which are greatly diminished at some azimuths and takeoff angles,

222

Analysis of site parameters affecting natural attenuation in saturated soil. Master's thesis  

Science Conference Proceedings (OSTI)

This study investigated the natural attenuation mechanisms and some of the parameters affecting those mechanisms in the saturated zone. A literature search revealed numerous studies of various attenuation and the associated parameters. Much of the literature emphasized biodegradation as the most promising attenuation mechanism. BIOPLUME II(TM), a fate and transport model, was used to simulate the fate and transport of contaminant plume. The effects of the model parameters were investigated by observing the distance a contaminant plume was expected to migrate over a fifty year period. The investigation was limited by the model which excludes chemical reactions and some physical and physiochemical reactions. The model simulations indicated that parameters which exhibited significant influence on natural attenuation include hydraulic conductivity, reaeration, and coefficient of anaerobic biodegradation.

Potts, W.H.

1993-09-01T23:59:59.000Z

223

Attenuation-Based Remedies in the Subsurface Applied Field Research Initiative (ABRS AFRI)  

Energy.gov (U.S. Department of Energy (DOE))

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

224

Evaluation and Improvement of an Iterative Scattering Correction Scheme for in situ Absorption and Attenuation Measurements  

Science Conference Proceedings (OSTI)

The performance of several scattering correction schemes for reflecting-tube absorption and beam attenuation measurements is evaluated with data collected in European shelf seas. Standard scattering correction procedures for absorption ...

David McKee; Jacek Piskozub; Rüdiger Röttgers; Rick A. Reynolds

2013-07-01T23:59:59.000Z

225

Rainfall Parameter Estimation from Dual-Radar Measurements Combining Reflectivity Profile and Path-integrated Attenuation  

Science Conference Proceedings (OSTI)

Rain rate estimation properties of multiparameter radar measurements combining radar reflectivity and microwave attenuations are studied through simulations using a two-year disdrometer dataset. In the first simulation, properties of “complete” ...

Toshiaki Kozu; Kenji Nakamura

1991-04-01T23:59:59.000Z

226

Rain Attenuation of Radar Echoes Considering Finite-Range Resolution and Using Drop Size Distributions  

Science Conference Proceedings (OSTI)

The classical rain attenuation correction scheme of Hitschfeld and Bordan (HIBO) and the newer iterative approach by Hildebrand (HL) are reconsidered. Although the motivation for the HL algorithm was an extension into ranges, where HIBO tends to ...

Gerhard Peters; Bernd Fischer; Marco Clemens

2010-05-01T23:59:59.000Z

227

Frontiers in Assessing the Role of Chemical Speciation and Natural Attenuation on the Bioavailability  

E-Print Network (OSTI)

1 Frontiers in Assessing the Role of Chemical Speciation and Natural Attenuation of contaminants in the terrestrial environment is greatly affected by a number of chemical factors and processes its fate, transport, and bioavailability. Traditionally, chemical extraction techniques have been

Sparks, Donald L.

228

A Simulation of the Optical Attenuation of TPB Coated Light-guide Detectors  

E-Print Network (OSTI)

This note describes simple simulations which were performed in order to understand the attenuation behaviors of acrylic light-guides operated in air and argon, which were characterized in \\cite{Baptista:2012bf}. Whilst these simulations are only at the level of sophistication of a toy model, they illustrate interesting non-exponential light attenuation effects and the differences between operating light-guide based detectors in argon and air environments. We investigate the effects of surface absorption, surface roughness and wavelength dependence, and use a model tuned on the light-guide attenuation curve measured in air to make a prediction of the light-guide attenuation curve in argon. This curve is compared with data from a liquid argon test stand, and an improvement over a simple exponential model is observed.

Jones, B J P

2013-01-01T23:59:59.000Z

229

Attenuation Calibration of an X-Band Weather Radar Using a Microwave Link  

Science Conference Proceedings (OSTI)

The attenuation of a radar signal is a serious problem facing meteorologists and hydrologists. In heavy rain, reflectivity information can be completely lost from large portions of a radar scan. The problem is particularly acute for X-band ...

A. R. Rahimi; A. R. Holt; G. J. G. Upton; S. Krämer; A. Redder; H-R. Verworn

2006-03-01T23:59:59.000Z

230

The Meteorological Parameterization of Specific Attenuation and Polarization Differential Phase Shift in Rain  

Science Conference Proceedings (OSTI)

This paper presents the theoretical bases and detailed polynomial expressions applicable to a wide range of naturally occurring drop size distributions for more accurate parameterizations of the specific attenuations at both horizontal and ...

A. R. Jameson

1993-11-01T23:59:59.000Z

231

Intrinsic Ambiguities in the Retrieval of Rain Rates from Radar Returns at Attenuating Wavelengths  

Science Conference Proceedings (OSTI)

It is well known that there are significant deterministic ambiguities inherent in trying to determine the particular rain-rate profile that produced some given sequence of air- or spaceborne radar echo powers at a single attenuating frequency. ...

Ziad S. Haddad; Eastwood Im; Stephen L. Durden

1995-12-01T23:59:59.000Z

232

Trends in Attenuation Coefficients in Athens, Greece, from 1954 to 1991  

Science Conference Proceedings (OSTI)

Unsworth and Monteith's attenuation coefficient TUM was calculated from midday cloudless sky data in Athens, Greece, for the period 1954 to 1991. An interdependence between TUM and the Linke factor TL was found and is expressed as a mathematical ...

C. P. Jacovides; N. A. Kaltsounides; G. P. Giannourakos; G. B. Kallos

1995-06-01T23:59:59.000Z

233

Dynamic effective mass of granular media  

E-Print Network (OSTI)

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.

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

2009-05-08T23:59:59.000Z

234

Twisted mass finite volume effects  

SciTech Connect

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.

Colangelo, Gilberto; Wenger, Urs; Wu, Jackson M. S. [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, 3012 Bern (Switzerland)

2010-08-01T23:59:59.000Z

235

RPU: a programmable ray processing unit for realtime ray tracing  

Science Conference Proceedings (OSTI)

Recursive ray tracing is a simple yet powerful and general approach for accurately computing global light transport and rendering high quality images. While recent algorithmic improvements and optimized parallel software implementations have increased ... Keywords: hardware architecture, programmable shading, ray processing unit, ray tracing

Sven Woop; Jörg Schmittler; Philipp Slusallek

2005-07-01T23:59:59.000Z

236

Fluctuation X-Ray Scattering  

SciTech Connect

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

Saldin, PI: D. K.; Co-I's: J. C. H. Spence and P. Fromme

2013-01-25T23:59:59.000Z

237

Mass Market Demand Response  

NLE Websites -- All DOE Office Websites (Extended Search)

Mass Market Demand Response Mass Market Demand Response Speaker(s): Karen Herter Date: July 24, 2002 - 12:00pm Location: Bldg. 90 Demand response programs are often quickly and poorly crafted in reaction to an energy crisis and disappear once the crisis subsides, ensuring that the electricity system will be unprepared when the next crisis hits. In this paper, we propose to eliminate the event-driven nature of demand response programs by considering demand responsiveness a component of the utility obligation to serve. As such, demand response can be required as a condition of service, and the offering of demand response rates becomes a requirement of utilities as an element of customer service. Using this foundation, we explore the costs and benefits of a smart thermostat-based demand response system capable of two types of programs: (1) a mandatory,

238

Single event mass spectrometry  

DOE Patents (OSTI)

A means and method for single event time of flight mass spectrometry for analysis of specimen materials. The method of the invention includes pulsing an ion source imposing at least one pulsed ion onto the specimen to produce a corresponding emission of at least one electrically charged particle. The emitted particle is then dissociated into a charged ion component and an uncharged neutral component. The ion and neutral components are then detected. The time of flight of the components are recorded and can be used to analyze the predecessor of the components, and therefore the specimen material. When more than one ion particle is emitted from the specimen per single ion impact, the single event time of flight mass spectrometer described here furnis This invention was made with Government support under Contract No. W-7405-ENG82 awarded by the Department of Energy. The Government has certain rights in the invention.

Conzemius, Robert J. (Ames, IA)

1990-01-16T23:59:59.000Z

239

Real-time Studies of Shocked Polycrystalline Materials with Single-Pulse X-ray Diffraction  

Science Conference Proceedings (OSTI)

Characteristic K-? x-rays used for single-pulse XRD are conventionally produced by a 37-stage high-voltage Marx pulse generator coupled to a vacuum needle-and-washer x-ray diode via coaxial transmission line. A large field-of-view x-ray image plate detection system typically enables observation of several Debye-Scherrer rings. Recently, we have developed a fiber-optic reducer, coupled to a CCD camera, to obtain low-noise, large field-of-view images. The direct beam spot is produced by bremsstrahlung radiation attenuated by a twomillimeter tungsten beam stop. Determination of the direct beam position is necessary to perform the ring integration.

Dane V. Morgan

2011-05-25T23:59:59.000Z

240

Ultrahigh Energy Cosmic Rays Detection  

Science Conference Proceedings (OSTI)

The paper describes methods used for the detection of cosmic rays with energies above 1018 eV (UHECR

Carla Aramo

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

X-ray Security Screening  

Science Conference Proceedings (OSTI)

National and International Standards for X-ray Security Screening Applications. Summary: The primary objective of this ...

2013-03-13T23:59:59.000Z

242

Binary Pulsar Shock Emissions as Galactic Gamma-Ray Sources  

E-Print Network (OSTI)

We address several issues regarding the interpretation of galactic \\ggg-ray sources. We consider powerful pulsars in binaries producing X-ray and gamma-ray {\\it unpulsed} emission from the shock interaction of relativistic pulsar winds with circumbinary material. Nebular mass outflows from companion stars of binary pulsars can provide the right {\\it calorimeters} to transform a fraction of the electromagnetic and kinetic energy of pulsar winds into high energy radiation. We discuss the physics of interaction of relativistic pulsar winds with gaseous material and show that the conditions in pulsar binary systems might be ideal to constrain shock acceleration mechanisms and pulsar wind composition and structure. We briefly discuss the example of the 47~ms pulsar PSR~1259-63 orbiting around a massive Be~star companion and monitored by X-ray and gamma-ray instruments during its recent periastron passage. In addition to young pulsars in massive binaries, also a class of recycled millisecond pulsars in low-mass binaries can be interesting high energy emitters.

M. Tavani

1995-02-10T23:59:59.000Z

243

Binary pulsar shock emissions as galactic gamma-ray sources  

E-Print Network (OSTI)

We address several issues regarding the interpretation of galactic \\ggg-ray sources. We consider powerful pulsars in binaries producing X-ray and gamma-ray {\\it unpulsed} emission from the shock interaction of relativistic pulsar winds with circumbinary material. Nebular mass outflows from companion stars of binary pulsars can provide the right {\\it calorimeters} to transform a fraction of the electromagnetic and kinetic energy of pulsar winds into high energy radiation. We discuss the physics of interaction of relativistic pulsar winds with gaseous material and show that the conditions in pulsar binary systems might be ideal to constrain shock acceleration mechanisms and pulsar wind composition and structure. We briefly discuss the example of the 47~ms pulsar PSR~1259-63 orbiting around a massive Be~star companion and monitored by X-ray and gamma-ray instruments during its recent periastron passage. In addition to young pulsars in massive binaries, also a class of recycled millisecond pulsars in low-mass bin...

Tavani, M

1995-01-01T23:59:59.000Z

244

Sensitivity of the FERMI Detectors to Gamma-Ray Bursts from Evaporating Primordial Black Holes (PBHs)  

E-Print Network (OSTI)

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).

T. N. Ukwatta; Jane H. MacGibbon; W. C. Parke; K. S. Dhuga; S. Rhodes; A. Eskandarian; N. Gehrels; L. Maximon; D. C. Morris

2010-03-23T23:59:59.000Z

245

X-ray afterglows from gamma-ray bursts  

E-Print Network (OSTI)

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.

M. Tavani

1997-03-24T23:59:59.000Z

246

A Theory of Gamma-Ray Bursts  

E-Print Network (OSTI)

We present a specific scenario for the link between GRB and hypernovae, based on Blandford-Znajek extraction of black-hole spin energy. Such a mechanism requires a high angular momentum in the progenitor object. The observed association of gamma-ray bursts with type Ibc supernovae leads us to consider massive helium stars that form black holes at the end of their lives as progenitors. We combine the numerical work of MacFadyen & Woosley with analytic calculations, to show that about 1E53 erg each are available to drive the fast GRB ejecta and the supernova. The GRB ejecta are driven by the power output through the open field lines, whereas the supernova is powered by closed filed lines and jet shocks. We also present a much simplified approximate derivation of these energetics. Helium stars that leave massive black-hole remnants in special ways, namely via soft X-ray transients or very massive WNL stars. Since binaries naturally have high angular momentum, we propose a link between black-hole transients and gamma-ray bursts. Recent observations of one such transient, GRO J1655-40/Nova Scorpii 1994, explicitly support this connection: its high space velocity indicates that substantial mass was ejected in the formation of the black hole, and the overabundance of alpha-nuclei, especially sulphur, indicates that the explosion energy was extreme, as in SN 1998bw/GRB 980425. (abstract shortened)

G. E. Brown; C. -H. Lee; R. A. M. J. Wijers; H. K. Lee; G. Israelian; H. A. Bethe

2000-03-23T23:59:59.000Z

247

Tunable X-ray source  

DOE Patents (OSTI)

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.

Boyce, James R. (Williamsburg, VA)

2011-02-08T23:59:59.000Z

248

Cost prediction for ray shooting  

Science Conference Proceedings (OSTI)

The ray shooting problem arises in many different contexts. For example, solving it efficiently would remove a bottleneck when images are ray-traced in computer graphics. Unfortunately, theoretical solutions to the problem are not very practical, ... Keywords: average performance, cost model, cost prediction, octree, ray shooting, space decomposition

Boris Aronov; Hervé Brönnimann; Allen Y. Chang; Yi-Jen Chiang

2002-06-01T23:59:59.000Z

249

Cosmic Ray Telescopes  

NLE Websites -- All DOE Office Websites (Extended Search)

Cosmic Ray Muon Detectors Cosmic Ray Muon Detectors Particle Physics Using Nature's Accelerator Somewhere out there is a list of "10 Things a Physics Teacher is Least Likely to Say." If one were to find this list, it would have on it such gems as #7. Let's challenge the PE Dept to a game of rugby and #4. I don't care if you understand the concept, just give me the correct answer to 12 sig figs. Finally, you'd get down to the biggie, the thing physics teachers never say: #1. Let's do a particle physics lab right here at Podunk Corners High! The traditional reasons for this are that everyone knows that particle physics is only done with Vastly Expensive and Complicated Equipment run by casts of thousands of Highly Qualified Scientists and that particle physics is Difficult and Arcane.

250

Superparticle Mass Window from Leptogenesis and Decaying Gravitino Dark Matter  

E-Print Network (OSTI)

Gravitino dark matter, together with thermal leptogenesis, implies an upper bound on the masses of superparticles. In the case of broken R-parity the constraints from primordial nucleosynthesis are naturally satisfied and decaying gravitinos lead to characteristic signatures in high energy cosmic rays. We analyse the implications for supergravity models with universal boundary conditions at the grand unification scale. Together with low-energy observables one obtains a window of superparticle masses, which will soon be probed at the LHC, and a range of allowed reheating temperatures.

Wilfried Buchmuller; Motoi Endo; Tetsuo Shindou

2008-09-26T23:59:59.000Z

251

Strange and charm meson masses from twisted mass lattice QCD  

E-Print Network (OSTI)

We present first results of a 2+1+1 flavor twisted mass lattice QCD computation of strange and charm meson masses. We focus on D and D_s mesons with spin J = 0,1 and parity P = -,+.

Martin Kalinowski; Marc Wagner

2012-12-03T23:59:59.000Z

252

EMSL: Capabilities: Mass Spectrometry: Next-Generation Mass Spectrometry  

NLE Websites -- All DOE Office Websites (Extended Search)

Next-Generation Mass Spectrometry Next-Generation Mass Spectrometry Additional Information Meet the Mass Spectrometry Experts Related EMSL User Projects Mass Spectrometry Tools are Applied to all Science Themes Next-Generation Mass Spectrometry Proteomics Research Resource for Integrative Biology Biological and Environmental Research - PNNL Proteomics PNNL's Biological MS Data and Software Distribution Center Mass Spectrometry brochure EMSL is committed to offering state-of-the-art instruments to its users. At a workshop in January of 2008, EMSL mass spectrometry experts joined experts from many universities, private companies, and government institutions and laboratories at a conference held at the National High Magnetic Field Laboratory in Tallahassee Florida. Workshop participants reviewed the state of the art of high-performance mass spectrometers,

253

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

Science Conference Proceedings (OSTI)

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.

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

2009-07-06T23:59:59.000Z

254

LONG GAMMA-RAY TRANSIENTS FROM COLLAPSARS  

Science Conference Proceedings (OSTI)

In the collapsar model for common gamma-ray bursts (GRBs), the formation of a centrifugally supported disk occurs during the first {approx}10 s following the collapse of the iron core in a massive star. This only occurs in a small fraction of massive stellar deaths, however, and requires unusual conditions. A much more frequent occurrence could be the death of a star that makes a black hole and a weak or absent outgoing shock, but in a progenitor that only has enough angular momentum in its outermost layers to make a disk. We consider several cases where this is likely to occur-blue supergiants with low mass-loss rates, tidally interacting binaries involving either helium stars or giant stars, and the collapse to a black hole of very massive pair-instability supernovae. These events have in common the accretion of a solar mass or so of material through a disk over a period much longer than the duration of a common GRB. A broad range of powers is possible, 10{sup 47}-10{sup 50} erg s{sup -1}, and this brightness could be enhanced by beaming. Such events were probably more frequent in the early universe where mass-loss rates were lower. Indeed, this could be one of the most common forms of gamma-ray transients in the universe and could be used to study first generation stars. Several events could be active in the sky at any one time. Recent examples of this sort of event may have been the Swift transients Sw-1644+57, Sw-2058+0516, and GRB 101225A.

Woosley, S. E. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Heger, Alexander, E-mail: woosley@ucolick.org, E-mail: alex@physics.umn.edu [Minnesota Institute of Astrophysics, School of Physics and Astronomy, University of Minnesota, Twin Cities, Minneapolis, MN 55455 (United States)

2012-06-10T23:59:59.000Z

255

MassMass transfer andtransfer and separation technologyseparation technology  

E-Print Network (OSTI)

Driving force Apparatus Heat exchange Energy T Heat exchanger Gas absorption Mass G L c y-y* Packed towerGas absorption Mass G L c, y-y* Packed tower, or tray column Gas desorption Mass L G c, y*-y Packed tower tower, or tray column and B from a mix Vaporisation cooling Energy, water h (enthalpy) Spray tower

Zevenhoven, Ron

256

An X-ray Reprocessing Model of Disk Thermal Emission in Type 1 Seyfert Galaxies  

E-Print Network (OSTI)

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.

James Chiang

2002-02-12T23:59:59.000Z

257

Scanning x-ray microscope  

Science Conference Proceedings (OSTI)

A scanning x-ray microscope is described including: an x-ray source capable of emitting a beam of x-rays; a collimator positioned to receive the beam of x-rays and to collimate this beam, a focusing cone means to focus the beam of x-rays, directed by the collimator, onto a focal plane, a specimen mount for supporting a specimen in the focal plane to receive the focused beam of x-rays, and x-ray beam scanning means to relatively move the specimen and the focusing cone means and collimator to scan the focused x-ray beam across the specimen. A detector is disposed adjacent the specimen to detect flourescent photons emitted by the specimen upon exposure to the focused beam of x-rays to provide an electrical output representative of this detection. Means are included for displaying and/or recording the information provided by the output from the detector, as are means for providing information to the recording and/or display means representative of the scan rate and position of the focused x-ray beam relative to the specimen whereby the recording and/or display means can correlate the information received to record and/or display quantitive and distributive information as to the quantity and distribution of elements detected in the specimen. Preferably there is provided an x-ray beam modulation means upstream, relative to the direction of emission of the xray beam, of the focusing cone means.

Wang, C.

1982-02-23T23:59:59.000Z

258

X-ray lithography source  

SciTech Connect

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.

Piestrup, Melvin A. (Woodside, CA); Boyers, David G. (Mountain View, CA); Pincus, Cary (Sunnyvale, CA)

1991-01-01T23:59:59.000Z

259

X-ray lithography source  

DOE Patents (OSTI)

A high-intensity, inexpensive X-ray source for X-ray lithography for the production of integrated circuits is disclosed. 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 eliminating 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 excellent moderate-priced X-ray source for lithography. 26 figures.

Piestrup, M.A.; Boyers, D.G.; Pincus, C.

1991-12-31T23:59:59.000Z

260

The chemistry of high-mass star formation  

E-Print Network (OSTI)

This paper reviews the chemistry of star-forming regions, with an emphasis on the formation of high-mass stars. We first outline the basic molecular processes in dense clouds, their implementation in chemical models, and techniques to measure molecular abundances. Then, recent observational, theoretical and laboratory developments are reviewed on the subjects of hot molecular cores, cosmic-ray ionization, depletion and deuteration, and oxygen chemistry. The paper concludes with a summary of outstanding problems and future opportunities.

Floris F. S. van der Tak

2005-06-07T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

"Gravitational mass" of information?  

E-Print Network (OSTI)

We hypothesize possible new types of forces that would be the result of new types of interactions, static and a slow transient, between objects with related information contents (pattern). Such mechanism could make material composition dependence claimed by Fishbach, et al in Eotvos type experiments plausible. We carried out experiments by using a high-resolution scale with the following memories: USB-2 flash drives (1-16GB), DVD and CD disks to determine if such an interaction exist/detectable with a scale resolution of 10 microgram with these test objects. We applied zero information, white noise and 1/f noise type data. Writing or deleting the information in any of these devices causes peculiar negative weight transients, up to milligrams (mass fraction around 10^-5), which is followed by various types of relaxation processes. These relaxations have significantly different dynamics compared to transients observed during cooling after stationary external heating. Interestingly, a USB-1 MP3 player has also developed comparable transient mass loss during playing music. A classical interpretation of the negative weight transients could be absorbed water in hygroscopic components however comparison of relaxation time constants with air humidity data does not support an obvious explanation. Another classical interpretation with certain contribution is the lifting Bernoulli force caused by the circulation due to convection of the warm air. However, in this case all observed time constants with a device should have been the same unless some hidden parameter causes the observed variations. Further studies are warranted to clarify if there is indeed a new force, which is showing up as negative mass at weight measurement when high-density structural information is changed or read out (measured).

Laszlo B. Kish

2007-11-08T23:59:59.000Z

262

MASS SPECTROMETER LEAK  

DOE Patents (OSTI)

An improved valve is described for precisely regulating the flow of a sample fluid to be analyzed, such as in a mass spectrometer, where a gas sample is allowed to "leak" into an evacuated region at a very low, controlled rate. The flow regulating valve controls minute flow of gases by allowing the gas to diffuse between two mating surfaces. The structure of the valve is such as to prevent the corrosive feed gas from contacting the bellows which is employed in the operation of the valve, thus preventing deterioration of the bellows.

Shields, W.R.

1960-10-18T23:59:59.000Z

263

HIGEE Mass Transfer  

E-Print Network (OSTI)

Distillation, absorption, and gas stripping have traditionally been performed in tall columns utilizing trays or packing. Columns perform satisfactorily, but have characteristics which may be disadvantages in some applications: Large size, particularly height; high weight; high cost of installation; difficulty in modularization; foaming for certain systems; must be vertical, especially for trayed towers; large liquid inventory; difficulty in modifying column internals once installed; start up time to reach steady state conditions in excessive. Many of these disadvantages can be overcome by use of HIGEE, an innovative vapor-liquid mass transfer system which utilizes a rotating bed of packing to achieve high efficiency separations, and consequent reduction in size and weight.

Mohr, R. J.; Fowler, R.

1986-06-01T23:59:59.000Z

264

Heat and mass exchanger  

Science Conference Proceedings (OSTI)

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.

Lowenstein, Andrew (Princeton, NJ); Sibilia, Marc J. (Princeton, NJ); Miller, Jeffrey A. (Hopewell, NJ); Tonon, Thomas (Princeton, NJ)

2011-06-28T23:59:59.000Z

265

LIGHT CURVES OF SWIFT GAMMA RAY BURSTS  

E-Print Network (OSTI)

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. Subject headings: gamma-rays: bursts 1.

Paolo Cea

2006-01-01T23:59:59.000Z

266

The Birmingham-CfA cluster scaling project - II. Mass composition and distribution  

E-Print Network (OSTI)

We investigate the spatial distribution of the baryonic and non-baryonic mass components in a sample of 66 virialized systems. We have used X-ray measurements to determine the deprojected temperature and density structure of the intergalactic medium and have employed these to map the underlying gravitational potential. In addition, we have measured the deprojected spatial distribution of galaxy luminosity for a subset of this sample, spanning over 2 decades in mass. With this combined X-ray/optical study we examine the scaling properties of the baryons and address the issue of mass-to-light (M/L) ratio in groups and clusters of galaxies. We measure a median mass-to-light ratio of 249 h70 M/L (solar) in the rest frame B_j band, in good agreement with other measurements based on X-ray determined masses. There is no trend in M/L with X-ray temperature and no significant trend for mass to increase faster than luminosity: M \\propto \\L_{B,j}^{1.08 +/- 0.12}. This implied lack of significant variation in star format...

Sanderson, A J R

2003-01-01T23:59:59.000Z

267

Determining the neutrino mass hierarchy  

Science Conference Proceedings (OSTI)

In this proceedings I review the physics that future experiments will use to determine the neutrino mass hierarchy.

Parke, Stephen J.; /Fermilab

2006-07-01T23:59:59.000Z

268

Theoretical mass loss rates of cool main-sequence stars  

E-Print Network (OSTI)

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.

V. Holzwarth; M. Jardine

2006-11-14T23:59:59.000Z

269

Linear electric field mass spectrometry  

DOE Patents (OSTI)

A mass spectrometer and methods for mass spectrometry. 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.

McComas, David J. (Los Alamos, NM); Nordholt, Jane E. (Los Alamos, NM)

1992-01-01T23:59:59.000Z

270

Linear electric field mass spectrometry  

DOE Patents (OSTI)

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.

McComas, D.J.; Nordholt, J.E.

1992-12-01T23:59:59.000Z

271

Mass Transport within Soils  

Science Conference Proceedings (OSTI)

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

McKone, Thomas E.

2009-03-01T23:59:59.000Z

272

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

SciTech Connect

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.

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

2011-08-04T23:59:59.000Z

273

Study of the Neutron Flux and Dpa Attenuation in the Reactor Pressure-Vessel Wall  

Science Conference Proceedings (OSTI)

The study of the neutron flux and dpa attenuation in the reactor pressure vessel (PV) wall presented in this work was performed with state-of-the art methods currently used to determine PV fluxes, the BUGLE-96 cross-section library, and the iron displacement cross sections derived from ENDF/B-VI data. The calculations showed that the RG 1.99, Rev. 2, extrapolation formula predicts slower--and therefore conservative--attenuation of the neutron flux (E > 1MeV) in the PV wall. More importantly, the calculations gave slower attenuation of the dpa rate in the PV wall than the attenuation predicted by the formula. The slower dpa rate attenuation was observed for all the cases considered, which included two different PWRs, and several configurations obtained by varying the PV wall thickness and thermal shield thickness. For example, for a PV wall thickness of {approximately}24 cm, the calculated ratio of the dpa rate at 1/4 and 3/4 of the PV wall thickness to the dpa value on the inner PV surface is {approximately}14% and 19% higher, respectively, than predicted by the RG 1.99, Rev. 2, formula.

Remec, I.

1999-06-01T23:59:59.000Z

274

dosimetry of x-rays, gamma rays and electrons  

Science Conference Proceedings (OSTI)

... NIST and BIPM Standards for Air Kerma in Medium-Energy X-rays ... of the codes are available from the Government Printing Office, Washington, DC ...

2013-06-28T23:59:59.000Z

275

X-ray Flares in Gamma-Ray Bursts.  

E-Print Network (OSTI)

??Data from the Swift mission have now shown that flares are a common component of Gamma-Ray Burst afterglows, appearing in roughly 50% of GRBs to… (more)

Morris, David

2008-01-01T23:59:59.000Z

276

Baryon Mass Extrapolation  

E-Print Network (OSTI)

Consideration of the analytical properties of pion-induced baryon self-energies leads to new functional forms for the extrapolation of light baryon masses. These functional forms reproduce the leading non-analytic behavior of chiral perturbation theory, the correct heavy-quark limit and have the advantage of containing information on the extended structure of hadrons. The forms involve only three unknown parameters which may be optimized by fitting to present lattice data. Recent dynamical fermion results from CP-PACS and UK-QCD are extrapolated using these new functional forms. We also use these functions to probe the limit of the chiral perturbative regime and shed light on the applicability of chiral perturbation theory to the extrapolation of present lattice QCD results.

Derek B. Leinweber; Anthony W. Thomas; Kazuo Tsushima; Stewart V. Wright

1999-09-14T23:59:59.000Z

277

Explosive hydrogen burning during type I X-ray bursts  

E-Print Network (OSTI)

Explosive hydrogen burning in type I X-ray bursts (XRBs) comprise charged particle reactions creating isotopes with masses up to A~100. Since charged particle reactions in a stellar environment are very temperature sensitive, we use a realistic time-dependent general relativistic and self-consistent model of type I x-ray bursts to provide accurate values of the burst temperatures and densities. This allows a detailed and accurate time-dependent identification of the reaction flow from the surface layers through the convective region and the ignition region to the neutron star ocean. Using this, we determine the relative importance of specific nuclear reactions in the X-ray burst.

Jacob Lund Fisker; Hendrik Schatz; Friedrich-Karl Thielemann

2007-03-13T23:59:59.000Z

278

Miniature x-ray source  

DOE Patents (OSTI)

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.

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)

2002-01-01T23:59:59.000Z

279

A Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles  

Open Energy Info (EERE)

Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Caldera, New Mexico Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Journal Article: A Shallow Attenuating Anomaly Inside The Ring Fracture Of The Valles Caldera, New Mexico Details Activities (4) Areas (2) Regions (0) Abstract: Spectral ratios of teleseismic direct and scattered P waves observed in the Valles Caldera, New Mexico, show a systematic pattern of low amplitudes at sites inside the caldera relative to sites on or outside the ring fracture. Waveforms recorded at caldera stations are considerably more complex than those recorded outside the caldera. The data used in this study were collected during a passive seismic monitoring experiment conducted in 1987. Twenty-four teleseismic events were recorded on two

280

Attenuating Diesel Engine Emissions | U.S. DOE Office of Science (SC)  

Office of Science (SC) Website

Attenuating Diesel Attenuating Diesel Engine Emissions Laboratory Policy and Evaluation (LPE) LPE Home Staff M&O Contracts SC Laboratory Appraisal Process Laboratory Planning Process Work for Others in the Office of Science Laboratory Directed Research and Development (LDRD) DOE's Philosophy on LDRD Frequently Asked Questions Success Stories Brochures Additional Information LDRD Program Contacts Technology Transfer DOE National Laboratories Contact Information Laboratory Policy and Evaluation U.S. Department of Energy SC-32/Forrestal Building 1000 Independence Ave., SW Washington, DC 20585 P: (202) 586-5447 F: (202) 586-3119 Success Stories Attenuating Diesel Engine Emissions Print Text Size: A A A RSS Feeds FeedbackShare Page Early this decade, Argonne chemists developed a special catalyst that can

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281

Impact of Aerosols on Atmospheric Attenuation Loss in Central Receiver Systems: Preprint  

Science Conference Proceedings (OSTI)

Atmospheric attenuation loss between the heliostat field and receiver has been recognized as a significant source of loss in Central Receiver Systems. In clear sky situations, extinction of Direct Normal Irradiance (DNI) is primarily by aerosols in the atmosphere. When aerosol loading is high close to the surface the attenuation loss between heliostat and receivers is significantly influenced by the amount of aerosols present on a particular day. This study relates measured DNI to aerosol optical depths close to the surface of the earth. The model developed in the paper uses only measured DNI to estimate the attenuation between heliostat and receiver in a central receiver system. The requirement that only a DNI measurement is available potentially makes the model a candidate for widespread use.

Sengupta, M.; Wagner, M. J.

2011-08-01T23:59:59.000Z

282

Weak Lensing Mass Reconstruction of the Galaxy Cluster Abell 209  

E-Print Network (OSTI)

Weak lensing applied to deep optical images of clusters of galaxies provides a powerful tool to reconstruct the distribution of the gravitating mass associated to these structures. We use the shear signal extracted by an analysis of deep exposures of a region centered around the galaxy cluster Abell 209, at redshift z=0.2, to derive both a map of the projected mass distribution and an estimate of the total mass within a characteristic radius. We use a series of deep archival R-band images from CFHT-12k, covering an area of 0.3 deg^2. We determine the shear of background galaxy images using a new implementation of the modified Kaiser-Squires-Broadhurst pipeline for shear determination, which we has been tested against the ``Shear TEsting Program 1 and 2'' simulations. We use mass aperture statistics to produce maps of the 2 dimensional density distribution, and parametric fits using both Navarro-Frenk-White (NFW) and singular-isothermal-sphere profiles to constrain the total mass. The projected mass distribution shows a pronounced asymmetry, with an elongated structure extending from the SE to the NW. This is in general agreement with the optical distribution previously found by other authors. A similar elongation was previously detected in the X-ray emission map, and in the distribution of galaxy colours. The circular NFW mass profile fit gives a total mass of M_{200} = 7.7^{+4.3}_{-2.7} 10^{14} solar masses inside the virial radius r_{200} = 1.8\\pm 0.3 Mpc. The weak lensing profile reinforces the evidence for an elongated structure of Abell 209, as previously suggested by studies of the galaxy distribution and velocities.

S. Paulin-Henriksson; V. Antonuccio-Delogu; C. P. Haines; M. Radovich; A. Mercurio; U. Becciani

2007-01-28T23:59:59.000Z

283

Cosmic-ray Driven Outflows in Global Galaxy Disk Models  

E-Print Network (OSTI)

Galactic-scale winds are a generic feature of massive galaxies with high star formation rates across a broad range of redshifts. Despite their importance, a detailed physical understanding of what drives these mass-loaded global flows has remained elusive. In this paper, we explore the dynamical impact of cosmic rays by performing the first three-dimensional, adaptive mesh refinement simulations of an isolated starbursting galaxy that includes a basic model for the production, dynamics and diffusion of galactic cosmic rays. We find that including cosmic rays naturally leads to robust, massive, bipolar outflows from our 10^12 Msun halo, with a mass-loading factor Mout/SFR = 0.3 for our fiducial run. Other reasonable parameter choices led to mass-loading factors above unity. The wind is multiphase and is accelerated to velocities well in excess of the escape velocity. We employ a two-fluid model for the thermal gas and relativistic CR plasma and model a range of physics relevant to galaxy formation, including r...

Salem, Munier

2013-01-01T23:59:59.000Z

284

Constraining axion by polarized prompt emission from gamma ray bursts  

E-Print Network (OSTI)

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.

A. Rubbia; A. S. Sakharov

2007-08-20T23:59:59.000Z

285

Gamma-ray burst populations.  

E-Print Network (OSTI)

??Over the last fifty years the field of gamma-ray bursts has shown incredible growth, but the amassing of data has also left observers and theorists… (more)

Virgili, Francisco J.

2011-01-01T23:59:59.000Z

286

Synchrotron X-ray Measurements  

Science Conference Proceedings (OSTI)

... fine structure (EXAFS) spectroscopy; (3) variable kinetic energy X-ray ... advanced materials is critical to the development and optimization of products ...

2012-10-04T23:59:59.000Z

287

X-ray Absorption Spectroscopy  

SciTech Connect

This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

Yano, Junko; Yachandra, Vittal K.

2009-07-09T23:59:59.000Z

288

ON THE MASS DISTRIBUTION AND BIRTH MASSES OF NEUTRON STARS  

Science Conference Proceedings (OSTI)

We investigate the distribution of neutron star masses in different populations of binaries, employing Bayesian statistical techniques. In particular, we explore the differences in neutron star masses between sources that have experienced distinct evolutionary paths and accretion episodes. We find that the distribution of neutron star masses in non-recycled eclipsing high-mass binaries as well as of slow pulsars, which are all believed to be near their birth masses, has a mean of 1.28 M{sub Sun} and a dispersion of 0.24 M{sub Sun }. These values are consistent with expectations for neutron star formation in core-collapse supernovae. On the other hand, double neutron stars, which are also believed to be near their birth masses, have a much narrower mass distribution, peaking at 1.33 M{sub Sun }, but with a dispersion of only 0.05 M{sub Sun }. Such a small dispersion cannot easily be understood and perhaps points to a particular and rare formation channel. The mass distribution of neutron stars that have been recycled has a mean of 1.48 M{sub Sun} and a dispersion of 0.2 M{sub Sun }, consistent with the expectation that they have experienced extended mass accretion episodes. The fact that only a very small fraction of recycled neutron stars in the inferred distribution have masses that exceed {approx}2 M{sub Sun} suggests that only a few of these neutron stars cross the mass threshold to form low-mass black holes.

Oezel, Feryal; Psaltis, Dimitrios; Santos Villarreal, Antonio [Department of Astronomy, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Narayan, Ramesh [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138,USA (United States)

2012-09-20T23:59:59.000Z

289

RECENT X-RAY VARIABILITY OF {eta} CARINAE: THE QUICK ROAD TO RECOVERY  

Science Conference Proceedings (OSTI)

We report continued monitoring of the superluminous binary system {eta} Car by the Proportional Counter Array on the Rossi X-ray Timing Observatory (RXTE) through the 2009 X-ray minimum. The RXTE campaign shows that the minimum began on 2009 January 16, consistent with the phasings of the two previous minima, and overall, the temporal behavior of the X-ray emission was similar to that observed by RXTE in the previous two cycles. However, important differences did occur. The 2-10 keV X-ray flux and X-ray hardness decreased in the 2.5 year interval leading up to the 2009 minimum compared to the previous cycle. Most intriguingly, the 2009 X-ray minimum was about 1 month shorter than either of the previous two minima. During the egress from the 2009 minimum the X-ray hardness increased markedly as it had during egress from the previous two minima, although the maximum X-ray hardness achieved was less than the maximum observed after the two previous recoveries. We suggest that the cycle-to-cycle variations, especially the unexpectedly early recovery from the 2009 X-ray minimum, might have been the result of a decline in {eta} Car's wind momentum flux produced by a drop in {eta} Car's mass loss rate or wind terminal velocity (or some combination), though if so the change in wind momentum flux required to match the X-ray variation is surprisingly large.

Corcoran, M. F.; Hamaguchi, K. [CRESST and X-ray Astrophysics Laboratory, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Pittard, J. M. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Russell, C. M. P.; Owocki, S. P. [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Parkin, E. R. [Institut d'Astrophysique et de Geophysique, Universite de Liege, 17, Allee du 6 Aout, B5c, B-4000 Sart Tilman (Belgium); Okazaki, A. [Faculty of Engineering, Hokkai-Gakuen University, Toyohira-ku, Sapporo 062-8605 (Japan)

2010-12-20T23:59:59.000Z

290

Precise measurement of the {sup 64}Ge mass and its effect on the rp process  

SciTech Connect

The Canadian Penning Trap mass spectrometer has been used to determine the mass excesses of {sup 64}Ge and {sup 64}Ga as -54344(30) keV and -58832.5(39) keV, respectively. Under typical conditions used for modeling x-ray bursts, {sup 64}Ge is confirmed as a waiting-point nuclide and can contribute up to 35.5 s to the timescale of the rp process at a peak x-ray burst temperature of 1.5 GK.

Clark, J. A. [Wright Nuclear Structure Laboratory, Yale University, New Haven, Connecticut 06520 (United States); Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Sharma, K. S. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Savard, G. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Physics, University of Chicago, Chicago, Illinois 60637 (United States); Levand, A. F.; Zhou, Z.; Seweryniak, D.; Trimble, W. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Wang, J. C. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada); Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Blank, B. [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Centre d'Etudes Nucleaires de Bordeaux-Gradignan, F-33175 Gradignan Cedex (France); Buchinger, F.; Crawford, J. E.; Gulick, S.; Lee, J. K. P. [Department of Physics, McGill University, Montreal, Quebec H3A 2T8 (Canada)

2007-03-15T23:59:59.000Z

291

Light Curves of Swift Gamma Ray Bursts  

E-Print Network (OSTI)

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.

Paolo Cea

2006-06-05T23:59:59.000Z

292

Monitored natural attenuation of manufactured gas plant tar mono- and polycyclic aromatic hydrocarbons in ground water: a 14-year field study  

Science Conference Proceedings (OSTI)

Site 24 was the subject of a 14-year (5110-day) study of a ground water plume created by the disposal of manufactured gas plant (MGP) tar into a shallow sandy aquifer approximately 25 years prior to the study. The ground water plume in 1988 extended from a well-defined source area to a distance of approximately 400 m down gradient. A system of monitoring wells was installed along six transects that ran perpendicular to the longitudinal axis of the plume centerline. The MGP tar source was removed from the site in 1991 and a 14-year ground water monitored natural attenuation (MNA) study commenced. The program measured the dissolved mono- and polycyclic aromatic hydrocarbons (MAHs and PAHs) periodically over time, which decreased significantly over the 14-year period. Naphthalene decreased to less than 99% of the original dissolved mass, with mass degradation rates of 0.30 per year (half-life 2.3 years). Bulk attenuation rate constants for plume centerline concentrations over time ranged from 0.33 {+-} 0.09 per year (half-life 2.3 {+-} 0.8 years) for toluene and 0.45 {+-} 0.06 per year (half-life 1.6 {+-} 0.2 years) for naphthalene. The hydrogeologic setting at Site 24, having a sandy aquifer, shallow water table, clay confining layer, and aerobic conditions, was ideal for demonstrating MNA. However, these results demonstrate that MNA is a viable remedial strategy for ground water at sites impacted by MAHs and PAHs after the original source is removed, stabilized, or contained.

Neuhauser, E.F.; Ripp, J.A.; Azzolina, N.A.; Madsen, E.L.; Mauro, D.M.; Taylor, T. [Foth Infrastructure & Environment LLC, Green Bay, WI (United States)

2009-07-01T23:59:59.000Z

293

Ultrahigh Energy Cosmic Rays and Prompt TeV Gamma Rays from Gamma Ray Bursts  

E-Print Network (OSTI)

Gamma Ray Bursts (GRBs) have been proposed as one {\\it possible} class of sources of the Ultrahigh Energy Cosmic Ray (UHECR) events observed up to energies $\\gsim10^{20}\\ev$. The synchrotron radiation of the highest energy protons accelerated within the GRB source should produce gamma rays up to TeV energies. Here we briefly discuss the implications on the energetics of the GRB from the point of view of the detectability of the prompt TeV gamma rays of proton-synchrotron origin in GRBs in the up-coming ICECUBE muon detector in the south pole.

Pijushpani Bhattacharjee; Nayantara Gupta

2003-05-12T23:59:59.000Z

294

The Influence of X-ray Emission on the Stellar Wind of O Stars  

E-Print Network (OSTI)

We study the influence of X-ray radiation on the wind parameters of O stars. For this purpose we use our own NLTE wind code. The X-ray emission (assumed to be generated in wind shocks) is treated as an input quantity. We study its influence on the mass-loss rate, terminal velocity and ionization state of the stellar wind of Galactic O stars.

Jiri Krticka; Jiri Kubat

2006-07-26T23:59:59.000Z

295

Supermassive Objects as Gamma-Ray Bursters  

E-Print Network (OSTI)

We propose that the gravitational collapse of supermassive objects ($ M\\ga 10^4 M_\\odot$), either as relativistic star clusters or as single supermassive stars (which may result from stellar mergers in dense star clusters), could be a cosmological source of $\\gamma$-ray bursts. These events could provide the seeds of the supermassive black holes observed at the center of many galaxies. Collapsing supermassive objects will release a fraction of their huge gravitational binding energy as thermal neutrino pairs. We show that the accompanying neutrino/antineutrino annihilation-induced heating could drive electron/positron ``fireball'' formation, relativistic expansion, and associated $\\gamma$-ray emission. The major advantage of this model is its energetics: supermassive object collapses are far more energetic than solar mass-scale compact object mergers; therefore, the conversion of gravitational energy to fireball kinetic energy in the supermassive object scenario need not be highly efficient, nor is it necessary to invoke directional beaming. The major weakness of this model is difficulty in avoiding a baryon loading problem for one dimensional collapse scenarios.

George M. Fuller; Xiangdong Shi

1997-11-04T23:59:59.000Z

296

Energy Functional for Nuclear Masses.  

E-Print Network (OSTI)

??An energy functional is formulated for mass calculations of nuclei across the nuclear chart with major-shell occupations as the relevant degrees of freedom. The functional… (more)

Bertolli, Michael Giovanni

2011-01-01T23:59:59.000Z

297

A hypercube Ray-tracer  

Science Conference Proceedings (OSTI)

We describe a hypercube ray-tracing program for rendering computer graphics. For small models, which fit in the memory of a single processor, the ray-tracer uses a scattered decomposition of pixels to balance the load, and achieves a very high efficiency. ...

J. Salmon; J. Goldsmith

1989-01-01T23:59:59.000Z

298

Static-light meson masses from twisted mass lattice QCD  

E-Print Network (OSTI)

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.

ETM Collaboration; Karl Jansen; Chris Michael; Andrea Shindler; Marc Wagner

2008-08-15T23:59:59.000Z

299

Gamma-Ray Bursts as a Cosmic Window for Galaxy Evolution  

E-Print Network (OSTI)

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.

I. F. Mirabel; D. B. Sanders; E. Le Floc'h

2000-04-03T23:59:59.000Z

300

High Quality Image of Biomedical Object by X-ray Refraction Based Contrast Computed Tomography  

SciTech Connect

Recently we have developed a new Computed Tomography (CT) algorithm for refraction contrast that uses the optics of diffraction-enhanced imaging. We applied this new method to visualize soft tissue which is not visualized by the current absorption based contrast. The meaning of the contrast that appears in refraction-contrast X-ray CT images must be clarified from a biologic or anatomic point of view. It has been reported that the contrast is made with the specific gravity map with a range of approximately 10 {mu}arc sec. However, the relationship between the contrast and biologic or anatomic findings has not been investigated, to our knowledge. We compared refraction-contrast X-ray CT images with microscopic X-ray images, and we evaluated refractive indexes of pathologic lesions on phase-contrast X-ray CT images. We focused our attenuation of breast cancer and lung cancer as samples. X-ray refraction based Computed Tomography was appeared to be a pathological ability to depict the boundary between cancer nest and normal tissue, and inner structure of the disease.

Hashimoto, E. [Department of Photon-Science, School of Advanced Studies, Graduate University for Advanced Studies (GUAS), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Maksimenko, A.; Hirano, K.; Hyodo, K. [Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Sugiyama, H. [Department of Photon-Science, School of Advanced Studies, Graduate University for Advanced Studies (GUAS), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Shimao, D. [Department of Health Sciences, Ibaraki prefectural University of Health Sciences, 4669-2Ami, Ami, Inashiki, Ibaraki, 300-0394 (Japan); Nishino, Y.; Ishikawa, T. [RIKEN Harima Institute, 1-1-1 Kouto, Mikazuki, Sayo, Hyogo, 679-5148 (Japan); Yuasa, T. [Department of Bio-system Engineering, Faculty of Engineering Yamagata University, 4-3-16 Jonan, Yonezawa, Yamagata 992-8510 (Japan); Ichihara, S. [Dept. of Path., Nagoya Med. Center, Nat. Hospital Organization, Naka-ku, Nagoya 460-0001 (Japan); Arai, Y. [Matsumoto Dental University, 1980 Hirooka, Shiojiri, Nagano (Japan); Ando, M. [Department of Photon-Science, School of Advanced Studies, Graduate University for Advanced Studies (GUAS), Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba, Ibaraki 305-0801 (Japan); Inst. of Sci. and Tech., Tokyo Univ. of Science, Yamasaki 2641, Noda, Chiba 278-8510 (Japan)

2007-01-19T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

O Star X-ray Line Profiles Explained by Radiation Transfer in Inhomogeneous Stellar Wind  

E-Print Network (OSTI)

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.

L. M. Oskinova; A. Feldmeier; W. -R. Hamann

2005-11-01T23:59:59.000Z

302

Gamma Ray Pulsars: Multiwavelength Observations  

E-Print Network (OSTI)

High-energy gamma rays are a valuable tool for studying particle acceleration and radiation in the magnetospheres of energetic pulsars. The seven or more pulsars seen by instruments on the Compton Gamma Ray Observatory (CGRO) 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. For all the known gamma-ray pulsars, multiwavelength observations and theoretical models based on such observations offer the prospect of gaining a broad understanding of these rotating neutron stars. The Gamma-ray Large Area Space Telescope (GLAST), now in planning for a launch in 2007, will provide a major advance in sensitivity, energy range, and sky coverage.

David J. Thompson

2003-12-10T23:59:59.000Z

303

In-Place Estimation of Wet Radome Attenuation at X Band  

Science Conference Proceedings (OSTI)

The effect of wet radome attenuation is estimated on a French operational X-band weather radar deployed in the Maritime Alps of southeastern France. As the radar is deployed in a remote location, the reflectivity factor in the immediate vicinity ...

Stephen J. Frasier; Fadela Kabeche; Jordi Figueras i Ventura; Hassan Al-Sakka; Pierre Tabary; Jeffrey Beck; Olivier Bousquet

2013-05-01T23:59:59.000Z

304

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

Science Conference Proceedings (OSTI)

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.

Papaneri, Amy B. [Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 (United States)] [Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 (United States); Wirblich, Christoph [Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107 (United States)] [Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Cann, Jennifer A.; Cooper, Kurt [Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick MD, 21702 (United States)] [Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick MD, 21702 (United States); Jahrling, Peter B. [Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 (United States) [Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 (United States); Integrated Research Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick MD, 21702 (United States); Schnell, Matthias J., E-mail: matthias.schnell@jefferson.edu [Department of Microbiology and Immunology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Jefferson Vaccine Center, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA 19107 (United States); Blaney, Joseph E., E-mail: jblaney@niaid.nih.gov [Emerging Viral Pathogens Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, MD 21702 (United States)

2012-12-05T23:59:59.000Z

305

Water destruction by X-rays in young stellar objects  

E-Print Network (OSTI)

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.

P. Stauber; J. K. Jorgensen; E. F. van Dishoeck; S. D. Doty; A. O. Benz

2006-02-06T23:59:59.000Z

306

Patient self-attenuation and technologist dose in positron emission tomography  

SciTech Connect

Positron emission tomography (PET), with 511-keV radiation and long patient-uptake times, presents unique radiation safety concerns. This two-part study considers aspects of PET radiation safety as they relate to PET suite design, dose to the public, and technologist occupational dose. In the first part of the study, the self-attenuation of radiation by patients' bodies was quantified. The radiation exposure was measured at three positions from 64 patients injected with fluorine-18 fluorodeoxyglucose (FDG) during the uptake period. Compared with an in vitro control used as a point source, a significant decrease in exposure (>40% at 1 m) was observed due to nonuniform distribution of FDG and attenuation within the patients. The attenuation data are consistent with results from simulations [M. E. Phelps, ''Comments and Perspectives,'' J. Nucl. Med. 45, 1601 (2004)] that treat the body as a uniform, water-filled cylinder. As distance is often the principal source of protection for 511-keV radiation, the considerable self-attenuation may allow for more compact PET suites. However, despite high patient self-attenuation, shielding, and standard precautionary measures, PET technologist occupational doses can remain quite high ({approx}12 mSv/year). The second part of this study tracked the daily dose received by PET technologists. Close technologist-patient interaction both during and following FDG administration, as much as 20 min/study, contribute to the high doses and point to the need for a more innovative approach to radiation protection for PET technologists.

Zeff, Benjamin W.; Yester, Michael V. [Department of Radiology, University of Alabama at Birmingham, Birmingham, Alabama 35233 (United States)

2005-04-01T23:59:59.000Z

307

Neutrino mass, a status report  

SciTech Connect

Experimental approaches to neutrino mass include kinematic mass measurements, neutrino oscillation searches at rectors and accelerators, solar neutrinos, atmospheric neutrinos, and single and double beta decay. The solar neutrino results yield fairly strong and consistent indications that neutrino oscillations are occurring. Other evidence for new physics is less consistent and convincing.

Robertson, R.G.H.

1993-08-01T23:59:59.000Z

308

Gravity and the Fermion Mass  

E-Print Network (OSTI)

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 $.

Kenneth Dalton

2004-09-08T23:59:59.000Z

309

Linear electric field mass spectrometry  

DOE Patents (OSTI)

A mass spectrometer is described having a low weight and low power requirement, for use in space. It can be used to analyze the ionized particles in the region of the spacecraft on which it is mounted. High mass resolution measurements are made by timing ions moving through a gridless cylindrically sysmetric linear electric field.

McComas, D.J.; Nordholt, J.E.

1991-03-29T23:59:59.000Z

310

The Diffuse Galactic Gamma-Ray Emission Model for GLAST LAT  

E-Print Network (OSTI)

Diffuse emission from the Milky Way dominates the gamma-ray sky. About 80% of the high-energy luminosity of the Milky Way comes from processes in the interstellar medium. The Galactic diffuse emission traces interactions of energetic particles, primarily protons and electrons, with the interstellar gas and radiation field, thus delivering information about cosmic-ray spectra and interstellar mass in distant locations. Additionally, the Galactic diffuse emission is the celestial foreground for the study of gamma-ray point sources and the extragalactic diffuse gamma-ray emission. We will report on the latest developments in the modelling of the Galactic diffuse emission, which will be used for the Gamma Ray Large Area Space Telescope (GLAST) investigations.

Porter, T A; Grenier, I A; Moskalenko, I V; Strong, A W

2007-01-01T23:59:59.000Z

311

The Diffuse Galactic Gamma-Ray Emission Model for GLAST LAT  

Science Conference Proceedings (OSTI)

Diffuse emission from the Milky Way dominates the gamma-ray sky. About 80% of the high-energy luminosity of the Milky Way comes from processes in the interstellar medium. The Galactic diffuse emission traces interactions of energetic particles, primarily protons and electrons, with the interstellar gas and radiation field, thus delivering information about cosmic-ray spectra and interstellar mass in distant locations. Additionally, the Galactic diffuse emission is the celestial foreground for the study of gamma-ray point sources and the extragalactic diffuse gamma-ray emission. We will report on the latest developments in the modeling of the Galactic diffuse emission, which will be used for the Gamma Ray Large Area Space Telescope (GLAST) investigations.

Porter, T.A.; /UC, Santa Cruz; Digel, S.W.; /SLAC /KIPAC, Menlo Park; Grenier, I.A.; /Saclay; Moskalenko, I.V.; /Stanford U., HEPL /KIPAC, Menlo Park; Strong, A.W.; /Garching, Max Planck Inst., MPE

2007-06-13T23:59:59.000Z

312

Current Topics in Gamma-Ray Astrophysics  

Science Conference Proceedings (OSTI)

... into e+–e– pairs ends up as rays. Figure 1 shows a calculation of -ray burst luminosity as ... The integrated energy in gamma-rays from the calculated ...

2000-03-14T23:59:59.000Z

313

Studying Gamma Ray Bursts from a  

E-Print Network (OSTI)

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

Â?umer, Slobodan

314

On the Origin of Ultra High Energy Cosmic Rays II  

Science Conference Proceedings (OSTI)

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.

Fowler, T K; Colgate, S; Li, H; Bulmer, R H; Pino, J

2011-03-08T23:59:59.000Z

315

Swift Pointing and the Association Between Gamma-Ray Bursts and Gravitational-Wave Bursts  

E-Print Network (OSTI)

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.

Lee Samuel Finn; Badri Krishnan; Patrick J. Sutton

2003-04-11T23:59:59.000Z

316

Lecture 7Lecture 7 The GammaThe Gamma--RayRay  

E-Print Network (OSTI)

Milagro­A TeV Observatory for Gamma Ray Bursts B.L. Dingus and the Milagro Collaboration Los energy gamma-rays from gamma-ray bursts. The highest energy gamma rays supply very strong constraints on the nature of gamma-ray burst sources as well as fundamental physics. Because the highest energy gamma-rays

317

GIANT X-RAY BUMP IN GRB 121027A: EVIDENCE FOR FALL-BACK DISK ACCRETION  

SciTech Connect

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.

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)

2013-04-20T23:59:59.000Z

318

X-Ray Data Booklet X-RAY DATA BOOKLET  

E-Print Network (OSTI)

.10.Re 1. Introduction Mendelevium (Z=101) and Lawrencium (Z=103) isotopes have been dis- covered nearly isotopes have been studied so far using prompt gamma- ray spectroscopy: the neutron-odd 253No [9

Meagher, Mary

319

Fiber fed x-ray/gamma ray imaging apparatus  

SciTech Connect

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.

Hailey, Charles J. (San Francisco, CA); Ziock, Klaus-Peter (Livermore, CA)

1992-01-01T23:59:59.000Z

320

Detectors of Cosmic Rays, Gamma Rays, and Neutrinos  

SciTech Connect

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.

Altamirano, A. [Departamento de Fisica, Informatica y Matematicas, Facultad de Ciencias y Filosofia, Universidad Peruana Cayetano Heredia (Peru); Centro de Tecnologias de Informacion y Comunicaciones (CTIC), Universidad Nacional de Ingenieria, Lima (Peru); Navarra, G. [Dipartimento di Fisica Generale dell'Universita' and INFN, Torino (Italy)

2009-04-30T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Discovery of Very High Energy Gamma-Rays from the Distant Flat Spectrum Radio Quasar 3C 279 with the MAGIC Telescope  

E-Print Network (OSTI)

The quasar 3C 279 is one of the best-studied flat spectrum radio quasars. It is located at a comparatively large redshift of z=0.536: E>100 GeV observations of such distant sources were until recently impossible both due to the expected steep energy spectrum and the expected attenuation of the gamma-rays by the extragalactic background light. Here we present results on the observation of 3C 279 with the MAGIC telescope in early 2006. We report the detection of a significant very high energy gamma-ray signal in the MAGIC energy range on the observation night of 2006 February 23.

Masahiro Teshima; Elisa Prandini; Rudolf Bock; Manel Errando; Daniel Kranich; Pratik Majumdar; Daniel Mazin; Elina Lindfors; Eckart Lorenz; Mose Mariotti; Villi Scalzotto; Robert Wagner

2007-09-10T23:59:59.000Z

322

COMPACT BINARY PROGENITORS OF SHORT GAMMA-RAY BURSTS  

SciTech Connect

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.

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)

2013-01-10T23:59:59.000Z

323

X-ray Spectral Properties of Gamma-Ray Bursts  

E-Print Network (OSTI)

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%.

T. E. Strohmayer; E. E. Fenimore; T. Murakami; A. Yoshida

1997-12-18T23:59:59.000Z

324

X-ray Transition Energies Search Form  

Science Conference Proceedings (OSTI)

[skip navigation] X-ray Transition Energies Database Main Page Search for X-ray transition energies by element(s), transition ...

325

NREL: Energy Sciences - B. Ray Stults  

NLE Websites -- All DOE Office Websites (Extended Search)

Chemical & Materials Science Computational Science News Events Printable Version B. Ray Stults Ph.D. - Associate Laboratory Director, Energy Sciences Ray Stults is the Associate...

326

THE QUIESCENT X-RAY PROPERTIES OF THE ACCRETING MILLISECOND X-RAY PULSAR AND ECLIPSING BINARY SWIFT J1749.4-2807  

Science Conference Proceedings (OSTI)

Swift J1749.4-2807 is a transient neutron star low-mass X-ray binary that contains an accreting millisecond X-ray pulsar spinning at 518 Hz. It is the first of its kind that displays X-ray eclipses, which holds significant promise to precisely constrain the mass of the neutron star. We report on a {approx_equal} 105 ks long XMM-Newton observation performed when Swift J1749.4-2807 was in quiescence. We detect the source at a 0.5-10 keV luminosity of {approx_equal}1 Multiplication-Sign 10{sup 33}(D/6.7 kpc){sup 2} erg s{sup -1}. The X-ray light curve displays three eclipses that are consistent in orbital phase and duration with the ephemeris derived during outburst. Unlike most quiescent neutron stars, the X-ray spectrum can be adequately described with a simple power law, while a pure-hydrogen atmosphere model does not fit the data. We place an upper limit on the 0.01-100 keV thermal luminosity of the cooling neutron star of {approx}< 2 Multiplication-Sign 10{sup 33} erg s{sup -1} and constrain its temperature to be {approx}< 0.1 keV (for an observer at infinity). Timing analysis does not reveal evidence for X-ray pulsations near the known spin frequency of the neutron star or its first overtone with a fractional rms of {approx}< 34% and {approx}< 28%, respectively. We discuss the implications of our findings for dynamical mass measurements, the thermal state of the neutron star, and the origin of the quiescent X-ray emission.

Degenaar, N. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Patruno, A.; Wijnands, R., E-mail: degenaar@umich.edu [Astronomical Institute 'Anton Pannekoek', University of Amsterdam, Postbus 94249, 1090 GE Amsterdam (Netherlands)

2012-09-10T23:59:59.000Z

327

X-ray flashes and X-ray rich gamma ray bursts. Memorie della Societa’ Astronomica Italiana  

E-Print Network (OSTI)

Abstract. X-ray flashes are detected in the Wide Field Cameras on BeppoSAX in the energy range 2-25 keV as bright X-ray sources lasting of the order of minutes, but remaining undetected in the Gamma Ray Bursts Monitor on BeppoSAX. They have properties very similar to the x-ray counterparts of GRBs and account for some of the Fast X-ray Transient events seen in almost every x-ray satellite. We review their X-ray properties and show that x-ray flashes are in fact very soft, x-ray rich, untriggered gamma ray bursts, in which the peak energy in 2-10 keV x-rays could be up to a factor of 100 larger than the peak energy in the 50-300 keV gamma ray range. The frequency is ? 100 yr ?1. 1 Fast X-ray Transients/High-latitude X-ray Transients Fast X-ray Transients have been observed with many x-ray satellites. In particular they are seen with x-ray instruments that scan the entire sky on a regular basis. Such events are detected in one sky scan and disappeared in the next, typically limiting the duration to be longer than a minute and shorter than a few hours. For this reason they are called Fast Transients. The first transients

John Heise; Jean In ’t Z; Peter M. Woods

2001-01-01T23:59:59.000Z

328

The Birmingham-CfA cluster scaling project - II. Mass composition and distribution  

E-Print Network (OSTI)

We investigate the spatial distribution of the baryonic and non-baryonic mass components in a sample of 66 virialized systems. We have used X-ray measurements to determine the deprojected temperature and density structure of the intergalactic medium and have employed these to map the underlying gravitational potential. In addition, we have measured the deprojected spatial distribution of galaxy luminosity for a subset of this sample, spanning over 2 decades in mass. With this combined X-ray/optical study we examine the scaling properties of the baryons and address the issue of mass-to-light (M/L) ratio in groups and clusters of galaxies. We measure a median mass-to-light ratio of 224 h70 M/L (solar) in the rest frame B_j band, in good agreement with other measurements based on X-ray determined masses. There is no trend in M/L with X-ray temperature and no significant trend for mass to increase faster than luminosity: M \\propto \\L_{B,j}^{1.08 +/- 0.12}. This implied lack of significant variation in star formation efficiency suggests that gas cooling cannot be greatly enhanced in groups, unless it drops out to form baryonic dark matter. Correspondingly, our results indicate that non-gravitational heating must have played a significant role in establishing the observed departure from self-similarity in low mass systems. The median baryon fraction for our sample is 0.162 h70^{-3/2}, which allows us to place an upper limit on the cosmological matter density, Omega_m agreement with the latest results from WMAP. We find evidence of a systematic trend towards higher central density concentration in the coolest haloes, indicative of an early formation epoch and consistent with hierarchical formation models.

A. J. R. Sanderson; T. J. Ponman

2003-07-25T23:59:59.000Z

329

Chip-Scale Quadrupole Mass Filters for Portable Mass Spectrometry  

E-Print Network (OSTI)

We report the design, fabrication, and characterization of a new class of chip-scale quadrupole mass filter (QMF). The devices are completely batch fabricated using a wafer-scale process that integrates the quadrupole ...

Cheung, Kerry

330

Gamma-Ray Burst Lines  

E-Print Network (OSTI)

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.

Michael S. Briggs

1999-10-20T23:59:59.000Z

331

X-ray Imaging Workshop  

NLE Websites -- All DOE Office Websites (Extended Search)

Imaging and Spectro-microscopy: Imaging and Spectro-microscopy: the Present and the Future Stanford Synchrotron Radiation Laboratory October 8-9, 2002 Organizers: John Miao & Keith Hodgson A workshop on "X-ray Imaging and Spectro-microscopy: the Present and the Future" was held on October 8-9, 2002. This workshop, organized by John Miao (SSRL) and Keith Hodgson (SSRL) provided a forum to discuss the scientific applications of a variety of imaging and spectro-microscopic techniques, including photoemission electron microscopy (PEEM), angle resolved photoemission spectroscopy (ARPES), coherent diffraction imaging, x-ray microscopy, micro-tomography, holographic imaging, and x-ray micro-probe. Twelve invited speakers discussed the important scientific applications of these techniques, and also predicted the future scientific directions with the advance of instrumentation and x-ray sources. The workshop was well attended with over fifty registered attendees.

332

Modeling gamma-ray bursts.  

E-Print Network (OSTI)

??Discovered serendipitously in the late 1960s, gamma-ray bursts (GRBs) are huge explosions of energy that happen at cosmological distances. They provide a grand physical playground… (more)

Maxham, Amanda

2011-01-01T23:59:59.000Z

333

Miniature x-ray source  

DOE Patents (OSTI)

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.

Trebes, James E. (Livermore, CA); Bell, Perry M. (Tracy, CA); Robinson, Ronald B. (Modesto, CA)

2000-01-01T23:59:59.000Z

334

Gamma Ray Bursts and CETI  

E-Print Network (OSTI)

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.

Frank D. Smith Jr

1993-02-10T23:59:59.000Z

335

Tokamak x ray diagnostic instrumentation  

SciTech Connect

Three classes of x-ray diagnostic instruments enable measurement of a variety of tokamak physics parameters from different features of the x-ray emission spectrum. (1) The soft x-ray (1 to 50 keV) pulse-height-analysis (PHA) diagnostic measures impurity concentrations from characteristic line intensities and the continuum enhancement, and measures the electron temperature from the continuum slope. (2) The Bragg x-ray crystal spectrometer (XCS) measures the ion temperature and neutral-beam-induced toroidal rotation velocity from the Doppler broadening and wavelength shift, respectively, of spectral lines of medium-Z impurity ions. Impurity charge state distributions, precise wavelengths, and inner-shell excitation and recombination rates can also be studied. X rays are diffracted and focused by a bent crystal onto a position-sensitive detector. The spectral resolving power E/..delta..E is greater than 10/sup 4/ and time resolution is 10 ms. (3) The x-ray imaging system (XIS) measures the spatial structure of rapid fluctuations (0.1 to 100 kHZ) providing information on MHD phenomena, impurity transport rates, toroidal rotation velocity, plasma position, and the electron temperature profile. It uses an array of silicon surface-barrier diodes which view different chords of the plasma through a common slot aperture and operate in current (as opposed to counting) mode. The effectiveness of shields to protect detectors from fusion-neutron radiation effects has been studied both theoretically and experimentally.

Hill, K.W.; Beiersdorfer, P.; Bitter, M.; Fredrickson, E.; Von Goeler, S.; Hsuan, H.; Johnson, L.C.; Liew, S.L.; McGuire, K.; Pare, V.

1987-01-01T23:59:59.000Z

336

Neutrinos from Gamma Ray Bursts  

E-Print Network (OSTI)

The observed fluxes of cosmic rays and gamma rays are used to infer the maximum allowed high-energy neutrino flux allowed for Gamma Ray Bursts (GRBs), following Mannheim, Protheroe, and Rachen (2000). It is shown that if GRBs produce the ultrahigh-energy cosmic rays, they should contribute (a) at least 10% of the extragalactic gamma ray background between 3 MeV and 30 GeV, contrary to their observed energy flux which is only a minute fraction of this flux, and (b) a cumulative neutrino flux a factor of 20 below the AMANDA (Neutrino 2000) limit on isotropic neutrinos. This could have two implications, either GRBs do not produce the ultrahigh energy cosmic rays or that the GRBs are strongly beamed and emit most of their power at energies well above 100 GeV implausibly increasing the energy requirements, but consistent with the marginal detections of a few low-redshift GRBs by MILAGRITO, HEGRA-AIROBICC, and the Tibet-Array. All crucial measurements to test the models will be available in the next few years. These are measurements of (i) high-energy neutrinos with AMANDA-ICECUBE or an enlarged ANTARES/NESTOR ocean detector, (ii) GRB redshifts from HETE-2 follow-up studies, and (iii) GRB spectra above 10 GeV with low-threshold imaging air Cherenkov telescopes such as MAGIC and the space telescopes AGILE and GLAST.

Karl Mannheim

2000-10-18T23:59:59.000Z

337

GALACTIC ULTRACOMPACT X-RAY BINARIES: DISK STABILITY AND EVOLUTION  

SciTech Connect

We study the mass-transfer rates and disk stability conditions of ultracompact X-ray binaries (UCXBs) using empirical time-averaged X-ray luminosities from Paper I and compiled information from the literature. The majority of UCXBs are consistent with evolutionary tracks for white dwarf donors. Three UCXBs with orbital periods longer than 40 minutes have mass-transfer rates above 10{sup -10} M{sub Sun} yr{sup -1}, inconsistent with white dwarf donor tracks. We show that if helium star donors can retain their initial high entropy, they can explain the observed mass-transfer rates of these UCXBs. Several UCXBs show persistent luminosities apparently below the disk instability limit for irradiated He accretion disks. We point out that a predominantly C and/or O disk (as observed in the optical spectra of several) lowers the disk instability limit, explaining this disagreement. The orbital period and low time-averaged mass-transfer rate of 2S 0918-549 provide evidence that the donor star is a low-entropy C/O white dwarf, consistent with optical spectra. We combine existing information to constrain the masses of the donors in 4U 1916-053 (0.064 {+-} 0.010 M{sub Sun }) and 4U 1626-67 (<0.036 M{sub Sun} for a 1.4 M{sub Sun} neutron star). We show that 4U 1626-67 is indeed persistent, and not undergoing a transient outburst, leaving He star models as the best explanation for the donor.

Heinke, C. O.; Ivanova, N.; Engel, M. C.; Pavlovskii, K.; Sivakoff, G. R.; Gladstone, J. C. [Physics Department, University of Alberta, 4-183 CCIS, Edmonton, AB T6G 2E1 (Canada); Cartwright, T. F., E-mail: heinke@ualberta.ca [International Space University, 1 rue Jean-Dominique Cassini, 67400 Illkirch-Graffenstaden (France)

2013-05-10T23:59:59.000Z

338

Mass-sensitive chemical preconcentrator  

DOE Patents (OSTI)

A microfabricated mass-sensitive chemical preconcentrator actively measures the mass of a sample on an acoustic microbalance during the collection process. The microbalance comprises a chemically sensitive interface for collecting the sample thereon and an acoustic-based physical transducer that provides an electrical output that is proportional to the mass of the collected sample. The acoustic microbalance preferably comprises a pivot plate resonator. A resistive heating element can be disposed on the chemically sensitive interface to rapidly heat and release the collected sample for further analysis. Therefore, the mass-sensitive chemical preconcentrator can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

Manginell, Ronald P. (Albuquerque, NM); Adkins, Douglas R. (Albuquerque, NM); Lewis, Patrick R. (Albuquerque, NM)

2007-01-30T23:59:59.000Z

339

Neutrino Mass and Grand Unification  

E-Print Network (OSTI)

Seesaw mechanism appears to be the simplest and most appealing way to understand small neutrino masses observed in recent experiments. It introduces three right handed neutrinos with heavy masses to the standard model, with at least one mass required by data to be close to the scale of conventional grand unified theories. This may be a hint that the new physics scale implied by neutrino masses and grand unification of forces are one and the same. Taking this point of view seriously, I explore different ways to resolve the puzzle of large neutrino mixings in grand unified theories such as SO(10) and models based on its subgroup $SU(2)_L\\times SU(2)_R\\times SU(4)_c$.

R. N. Mohapatra

2004-12-03T23:59:59.000Z

340

Thermal Mass and Demand Response  

NLE Websites -- All DOE Office Websites (Extended Search)

Thermal Mass and Demand Response Speaker(s): Gregor Henze Phil C. Bomrad Date: November 2, 2011 - 12:00pm Location: 90-4133 Seminar HostPoint of Contact: Janie Page The topic of...

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341

Neutrino Mass and Flavour Models  

E-Print Network (OSTI)

We survey some of the recent promising developments in the search for the theory behind neutrino mass and tri-bimaximal mixing, and indeed all fermion masses and mixing. We focus in particular on models with discrete family symmetry and unification, and show how such models can also solve the SUSY flavour and CP problems. We also discuss the theoretical implications of the measurement of a non-zero reactor angle, as hinted at by recent experimental measurements.

King, Stephen F

2009-01-01T23:59:59.000Z

342

Neutrino Mass and Flavour Models  

E-Print Network (OSTI)

We survey some of the recent promising developments in the search for the theory behind neutrino mass and tri-bimaximal mixing, and indeed all fermion masses and mixing. We focus in particular on models with discrete family symmetry and unification, and show how such models can also solve the SUSY flavour and CP problems. We also discuss the theoretical implications of the measurement of a non-zero reactor angle, as hinted at by recent experimental measurements.

Stephen F King

2009-09-16T23:59:59.000Z

343

The application of taylor weighting, digital phase shifters, and digital attenuators to phased-array antennas.  

SciTech Connect

Application of Taylor weighting (taper) to an antenna aperture can achieve low peak sidelobes, but combining the Taylor weighting with quantized attenuators and phase shifters at each radiating element will impact the performance of a phased-array antenna. An examination of array performance is undertaken from the simple point of view of the characteristics of the array factor. Design rules and guidelines for determining the Taylor-weighting parameters, the number of bits required for the digital phase shifter, and the dynamic range and number of bits required for the digital attenuator are developed. For a radar application, when each element is fed directly from a transmit/receive module, the total power radiated by the array will be reduced as a result of the taper. Consequently, the issue of whether to apply the taper on both transmit and receive configurations, or only on the receive configuration is examined with respect to two-way sidelobe performance.

Brock, Billy C.

2008-03-01T23:59:59.000Z

344

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

Science Conference Proceedings (OSTI)

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.

Bull, Diana L; Ochs, Margaret Ellen

2013-09-01T23:59:59.000Z

345

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

SciTech Connect

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.

Bull, Diana L; Ochs, Margaret Ellen

2013-09-01T23:59:59.000Z

346

Gamma-Ray Bursts, Ultra High Energy Cosmic Rays, and Cosmic Gamma-Ray Background  

E-Print Network (OSTI)

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.

Tomonori Totani

1998-10-14T23:59:59.000Z

347

Demand Shifting with Thermal Mass in Light and Heavy Mass Commercial Buildings  

E-Print Network (OSTI)

effort to understand pre-cooling thermal mass as a Demandof Building Thermal Mass to Offset Cooling Loads. ” ASHRAEKey words: Pre-cooling, demand response, thermal mass

Xu, Peng

2010-01-01T23:59:59.000Z

348

Irradiated integrated circuits dose-attenuation mapping using optically stimulated phosphors for packaging dosimetry  

Science Conference Proceedings (OSTI)

The feasibility of a dose mapping system using Optically Stimulated Luminescent (OSL) Phosphors is demonstrated. The OSL technique is briefly reviewed as well as its interest for calculation codes calibration. The sensors and the reading apparatus are presented. An example of attenuation dose map obtained for a Dual In Line Plastic Package (DIL) is given and the results compared to calculations with the code EGS4 PRESTA. Results obtained by experiment and simulation are discussed as well as the potentialities of the method.

Dusseau, L.; Polge, G.; Albert, L.; Magnac, Y.; Fesquet, J.; Gasiot, J. [Univ. Montpellier II (France); Bessiere, J.C. [CORAD P.I.T. Pompignane, Montpellier (France)

1998-12-01T23:59:59.000Z

349

Penning trap mass measurements on (99-109)$Cd with ISOLTRAP and implications on the rp process  

E-Print Network (OSTI)

Penning trap mass measurements on neutron-deficient Cd isotopes (99-109)Cd have been performed with the ISOLTRAP mass spectrometer at ISOLDE/CERN, all with relative mass uncertainties below 3*10^8. A new mass evaluation has been performed. The mass of 99Cd has been determined for the first time which extends the region of accurately known mass values towards the doubly magic nucleus 100Sn. The implication of the results on the reaction path of the rp process in stellar X-ray bursts is discussed. In particular, the uncertainty of the abundance and the overproduction created by the rp-process for the mass A = 99 is demonstrated by reducing the uncertainty of the proton-separation energy of 100In Sp(100In) by a factor of 2.5.

M. Breitenfeldt; G. Audi; D. Beck; K. Blaum; S. George; F. Herfurth; A. Herlert; A. Kellerbauer; H. -J. Kluge; M. Kowalska; D. Lunney; S. Naimi; D. Neidherr; H. Schatz; S. Schwarz; L. Schweikhard

2009-08-18T23:59:59.000Z

350

Intensity of Upward Muon Flux Due to Cosmic-Ray Neutrinos Produced in the Atmosphere  

DOE R&D Accomplishments (OSTI)

Calculations were performed to determine the upward going muon flux leaving the earth's surface after production by cosmic-ray neutrinos in the crust. Only neutrinos produced in the earth's atmosphere are considered. Rates of the order of one per 100 sq m/day might be expected if an intermediate boson exists and has a mass less than 2 Bev. (auth)

Lee, T. D.; Robinson, H.; Schwartz, M.; Cool, R.

1963-06-00T23:59:59.000Z

351

Search for a dark matter particle in high energy cosmic rays  

E-Print Network (OSTI)

Existing data hints that high energy cosmic ray experiments may offer the most promissing shot at finding a dark matter particle. A search in the PeV mass range is suggested, where the discovery of such a particle might help explain the GZK cutoff violation data.

Yukio Tomozawa

2008-04-09T23:59:59.000Z

352

Thermal Acoustic Sensor for High Pulse Energy X-ray FEL Beams  

SciTech Connect

The pulse energy density of X-ray FELs will saturate or destroy conventional X-ray diagnostics, and the use of large beam attenuation will result in a beam that is dominated by harmonics. We present preliminary results at the LCLS from a pulse energy detector based on the thermal acoustic effect. In this type of detector an X-ray resistant material (boron carbide in this system) intercepts the beam. The pulse heating of the target material produces an acoustic pulse that can be detected with high frequency microphones to produce a signal that is linear in the absorbed energy. The thermal acoustic detector is designed to provide first- and second-order calorimetric measurement of X-ray FEL pulse energy. The first-order calorimetry is a direct temperature measurement of a target designed to absorb all or most of the FEL pulse power with minimal heat leak. The second-order measurement detects the vibration caused by the rapid thermoelastic expansion of the target material each time it absorbs a photon pulse. Both the temperature change and the amplitude of the acoustic signal are directly related to the photon pulse energy.

Smith, T.J.; Frisch, J.C.; Kraft, E.M.; Loos, J.; /SLAC; Bentsen, G.S.; /Rochester U.

2011-12-13T23:59:59.000Z

353

Improvements to Regional Explosion Identification using Attenuation Models of the Lithosphere  

Science Conference Proceedings (OSTI)

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.

Pasyanos, M E; Walter, W R

2009-03-30T23:59:59.000Z

354

DISCREPANT HARDENING OBSERVED IN COSMIC-RAY ELEMENTAL SPECTRA  

Science Conference Proceedings (OSTI)

The balloon-borne Cosmic Ray Energetics And Mass experiment launched five times from Antarctica has achieved a cumulative flight duration of about 156 days above 99.5% of the atmosphere. The instrument is configured with complementary and redundant particle detectors designed to extend direct measurements of cosmic-ray composition to the highest energies practical with balloon flights. All elements from protons to iron nuclei are separated with excellent charge resolution. Here, we report results from the first two flights of {approx}70 days, which indicate hardening of the elemental spectra above {approx}200 GeV/nucleon and a spectral difference between the two most abundant species, protons and helium nuclei. These results challenge the view that cosmic-ray spectra are simple power laws below the so-called knee at {approx}10{sup 15} eV. This discrepant hardening may result from a relatively nearby source, or it could represent spectral concavity caused by interactions of cosmic rays with the accelerating shock. Other possible explanations should also be investigated.

Ahn, H. S.; Ganel, O.; Han, J. H.; Kim, K. C.; Lee, M. H.; Lutz, L.; Malinin, A. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Allison, P.; Beatty, J. J. [Department of Physics, Ohio State University, Columbus, OH 43210 (United States); Bagliesi, M. G.; Bigongiari, G.; Maestro, P.; Marrocchesi, P. S. [Department of Physics, University of Siena and INFN, Siena 53100 (Italy); Childers, J. T.; DuVernois, M. A. [School of Physics and Astronomy, University of Minnesota, MN 55414 (United States); Conklin, N. B.; Coutu, S.; Mognet, S. I. [Department of Physics, Penn State University, University Park, PA 16802 (United States); Jeon, J. A. [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Minnick, S. [Department of Physics, Kent State University Tuscarawas, New Philadelphia, OH 44663 (United States)], E-mail: seo@umd.edu (and others)

2010-05-01T23:59:59.000Z

355

Gamma ray bursts ROBERT S MACKAY  

E-Print Network (OSTI)

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

Rourke, Colin

356

Swift Pointing and Gravitational-Wave Bursts from Gamma-Ray Burst Events  

E-Print Network (OSTI)

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. Even upper limits on the gravitational-wave strength associated with gamma-ray bursts could constrain the gamma-ray burst model. This 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 bursts 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.

Lee Samuel Finn; Badri Krishnan; Patrick J. Sutton

2003-04-23T23:59:59.000Z

357

Color Superconductivity in Compact Stars and Gamma Ray Bursts  

E-Print Network (OSTI)

We study the effects of color superconductivity on the structure and formation of compact stars. We show that it is possible to satisfy most of recent observational boundaries on masses and radii if a diquark condensate forms in a hybrid or a quark star. Moreover, we find that a huge amount of energy, of the order of $10^{53}$ erg, can be released in the conversion from a (metastable) hadronic star into a (stable) hybrid or quark star, if the presence of a color superconducting phase is taken into account. Accordingly to the scenario proposed in Astrophys.J.586(2003)1250, the energy released in this conversion can power a Gamma Ray Burst. This mechanism can explain the recent observations indicating a delay, of the order of days or years, between a few Supernova explosions and the subsequent Gamma Ray Burst.

A. Drago; A. Lavagno; G. Pagliara

2003-04-08T23:59:59.000Z

358

The Electron Injection Spectrum Determined by Anomalous Excesses in Cosmic Ray, Gamma Ray, and Microwave Signals  

E-Print Network (OSTI)

Recent cosmic ray, gamma ray, and microwave signals observed by Fermi, PAMELA, and WMAP indicate an unexpected primary source of e+e- at 10-1000 GeV. We fit these data to "standard backgrounds" plus a new source, assumed to be a separable function of position and energy. For the spatial part, we consider three cases: annihilating dark matter, decaying dark matter, and pulsars. In each case, we use GALPROP to inject energy in log-spaced energy bins and compute the expected cosmic-ray and photon signals for each bin. We then fit a linear combination of energy bins, plus backgrounds, to the data. We use a non-parametric fit, with no prior constraints on the spectrum except smoothness and non-negativity. In addition, we consider arbitrary modifications to the energy spectrum of the "ordinary" primary source function, fixing its spatial part, finding this alone to be inadequate to explain the PAMELA or WMAP signals. We explore variations in the fits due to choice of magnetic field, primary electron injection index, spatial profiles, propagation parameters, and fit regularization method. Dark matter annihilation fits well, where our fit finds a mass of ~1 TeV and a boost factor times energy fraction of ~70. While it is possible for dark matter decay and pulsars to fit the data, unconventionally high magnetic fields and radiation densities are required near the Galactic Center to counter the relative shallowness of the assumed spatial profiles. We also fit to linear combinations of these three scenarios, though the fit is much less constrained.

Tongyan Lin; Douglas P. Finkbeiner; Gregory Dobler

2010-04-07T23:59:59.000Z

359

Relativistic Winds from Compact Gamma-Ray Sources: II. Pair Loading and Radiative Acceleration in Gamma-ray Bursts  

E-Print Network (OSTI)

We consider the effects of rapid pair creation by an intense pulse of gamma-rays propagating ahead of a relativistic shock. Side-scattered photons colliding with the main gamma-ray beam amplify the density of scattering charges. The acceleration rate of the pair-loaded medium is calculated, and its limiting bulk Lorentz factor related to the spectrum and compactness of the photon source. One obtains, as a result, a definite prediction for the relative inertia in baryons and pairs. The deceleration of a relativistic shock in the moving medium, and the resulting synchrotron emissivity, are compared with existing calculations for a static medium. The radiative efficiency is increased dramatically by pair loading. When the initial ambient density exceeds a critical value, the scattering depth traversed by the main gamma-ray pulse rises above unity, and the pulse is broadened. These considerations place significant constraints on burst progenitors: a pre-burst mass loss rate exceeding 10^{-5} M_\\odot per year is difficult to reconcile with individual pulses narrower than 10 s, unless the radiative efficiency is low. An anisotropic gamma-ray flux (on an angular scale \\Gamma^{-1} or larger) drives a large velocity shear that greatly increases the energy in the seed magnetic field forward of the propagating shock.

Christopher Thompson; Piero Madau

1999-09-06T23:59:59.000Z

360

Ultra-High-Energy Cosmic Rays from a Magnetized Strange Star Central Engine for Gamma-Ray Bursts  

E-Print Network (OSTI)

Ultra-high-energy cosmic rays (UHECRs) have been tried to be related to the most varied and powerful sources known in the universe. Gamma-ray bursts (GRBs) are natural candidates. Here, we argue that cosmic rays can be accelerated by large amplitude electromagnetic waves (LAEMWs) when the MHD approximation of the field in the wind generated by the GRB's magnetized central engine breaks down. The central engine considered here is a strange star born with differential rotation from the accretion induced conversion of a neutron star into a strange star in a low-mass X-ray binary system. The LAEMWs generated this way accelerate light ions to the highest energies $E = q\\eta\\Delta\\Phi_{max}$ with an efficiency $\\eta \\sim 10^{-1}$ that accounts for all plausible energy losses. Alternatively, we also consider the possibility that, once formed, the LAEMWs are unstable to creation of a relativistically strong electromagnetic turbulence due to an overturn instability. Under this assumption, a lower limit to the efficien...

Esquivel, O

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

QLC relation and neutrino mass hierarchy  

E-Print Network (OSTI)

neutrino mass matrix is generated at high energies, s 12 = cneutrino mass matrix is generated at low energy scales. Ontrino mass matrix is generated at some high energy scale. We

Ferrandis, Javier

2009-01-01T23:59:59.000Z

362

High-Resolution X-ray Imaging of the Colliding Wind Shock in WR147  

E-Print Network (OSTI)

We analyze new high-resolution Chandra X-ray images of the Wolf-Rayet binary system WR147. This system contains a WN8 star with an early-type companion located 0.6'' to its north, and is the only known early-type binary with a separation on the sky large enough for the wind-wind collision between the stars to currently be resolved at X-ray energies. The 5 ksec Chandra HRC-I image provides the first direct evidence for spatially extended X-ray emission in an early-type binary system. The X-ray emission peaks close to the position of the radio bow shock and north of the WN8 star. A deeper X-ray image is needed to accurately determine the degree of spatial extension, to exactly align the X-ray and optical/radio frames, and to determine whether part of the detected X-ray emission arises in the individual stellar winds. Simulated X-ray images of the wind-wind collision have a FWHM consistent with the data, and maximum likelihood fits suggest that a deeper observation may also constrain the inclination and wind momentum ratio of this system. However, as the WR wind dominates the colliding wind X-ray emission it appears unlikely that the mass-loss rate and the terminal velocity of the companion wind can be separately determined from X-ray observations. We also note an inconsistency between numerical and analytical estimates of the X-ray luminosity ratio of the stronger and weaker wind components, and conclude that the analytical results are in error.

J. M. Pittard; I. R. Stevens; P. M. Williams; A. M. T. Pollock; S. L. Skinner; M. F. Corcoran; A. F. J. Moffat

2002-04-12T23:59:59.000Z

363

The Effect of Mean and Differential Attenuation on the Precision and Accuracy of the Estimates of Reflectivity and Differential Reflectivity  

Science Conference Proceedings (OSTI)

Error propagation analysis is applied to evaluate the effects of correcting horizontal and differential attenuation on the precision of the estimates of reflectivity and differential reflectivity. The analysis shows that the loss of precision on ...

Enrico Torlaschi; Isztar Zawadzki

2003-03-01T23:59:59.000Z

364

A Surface Wind Model–Based Method to Estimate Rain-Induced Radar Path Attenuation over Ocean  

Science Conference Proceedings (OSTI)

The rainfall retrieved using the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) depends on estimating the radar signal path-integrated attenuation using the surface reference technique (SRT). This technique assumes uniform ...

Li Li; Eastwood Im; Stephen L. Durden; Ziad S. Haddad

2002-05-01T23:59:59.000Z

365

C-Band Attenuation by Tropical Rainfall in Darwin, Australia, Using Climatologically Tuned Ze-R Relations  

Science Conference Proceedings (OSTI)

The probability matching method (PMM) is used as a basis for estimating attenuation in tropical rains near Darwin, Australia. PMM provides a climatological relationship between measured radar reflectivity and rain rate, which includes the effects ...

David Atlas; Daniel Rosenfeld; David B. Wolff

1993-02-01T23:59:59.000Z

366

Application of an Apple-II Computer in Real-Time Data Processing of Microwave Radiation Attenuation by Rain  

Science Conference Proceedings (OSTI)

Using an Apple-II microcomputer, real-time data acquisition, processing, staring and display of 12 GHz microwave radiation attenuation by rain have been implemented. The computer-radiometer interface consists of an address decoder, two three-...

Song Qian

1989-02-01T23:59:59.000Z

367

Gamma-RayGamma-Ray Bursts: from SwiftBursts: from Swift  

E-Print Network (OSTI)

Gamma-RayGamma-Ray Bursts: from SwiftBursts: from Swift to GLASTto GLAST Bing ZhangBing ZhangGehrels, et al), et al) #12;Gamma-ray bursts: the mostGamma-ray bursts: the most violent explosions Bursts Apparently high gamma-ray efficiency. Highly magnetized flow? Roming et al., 2005 #12;Surprises

California at Santa Cruz, University of

368

A CATALOG OF SOLAR X-RAY PLASMA EJECTIONS OBSERVED BY THE SOFT X-RAY TELESCOPE ON BOARD YOHKOH  

Science Conference Proceedings (OSTI)

A catalog of X-ray plasma ejections (XPEs) observed by the Soft X-ray Telescope on board the Yohkoh satellite has been recently developed in the Astronomical Institute of University of Wroclaw. The catalog contains records of 368 events observed in years 1991-2001 including movies and cross-references to associated events like flares and coronal mass ejections (CMEs). One hundred sixty-three XPEs out of 368 in the catalog were not reported until now. A new classification scheme of XPEs is proposed in which morphology, kinematics, and recurrence are considered. The relation between individual subclasses of XPEs and the associated events was investigated. The results confirm that XPEs are strongly inhomogeneous, responding to different processes that occur in the solar corona. A subclass of erupting loop-like XPEs is a promising candidate to be a high-temperature precursor of CMEs.

Tomczak, M.; Chmielewska, E., E-mail: tomczak@astro.uni.wroc.pl, E-mail: chmielewska@astro.uni.wroc.pl [Astronomical Institute, University of Wroclaw, ul. Kopernika 11, PL-51-622 Wroclaw (Poland)

2012-03-01T23:59:59.000Z

369

ON DARK PEAKS AND MISSING MASS: A WEAK-LENSING MASS RECONSTRUCTION OF THE MERGING CLUSTER SYSTEM A520 ,  

SciTech Connect

Merging clusters of galaxies are unique in their power to directly probe and place limits on the self-interaction cross-section of dark matter. Detailed observations of several merging clusters have shown the intracluster gas to be displaced from the centroids of dark matter and galaxy density by ram pressure, while the latter components are spatially coincident, consistent with collisionless dark matter. This has been used to place upper limits on the dark matter particle self-interaction cross-section of order 1 cm{sup 2} g{sup -1}. The cluster A520 has been seen as a possible exception. We revisit A520 presenting new Hubble Space Telescope Advanced Camera for Surveys mosaic images and a Magellan image set. We perform a detailed weak-lensing analysis and show that the weak-lensing mass measurements and morphologies of the core galaxy-filled structures are mostly in good agreement with previous works. There is, however, one significant difference: We do not detect the previously claimed 'dark core' that contains excess mass with no significant galaxy overdensity at the location of the X-ray plasma. This peak has been suggested to be indicative of a large self-interaction cross-section for dark matter (at least {approx}5{sigma} larger than the upper limit of 0.7 cm{sup 2} g{sup -1} determined by observations of the Bullet Cluster). We find no such indication and instead find that the mass distribution of A520, after subtraction of the X-ray plasma mass, is in good agreement with the luminosity distribution of the cluster galaxies. We conclude that A520 shows no evidence to contradict the collisionless dark matter scenario.

Clowe, Douglas [Department of Physics and Astronomy, Ohio University, 251B Clippinger Labs, Athens, OH 45701 (United States); Markevitch, Maxim [NASA Goddard Space Flight Center, Code 662, 8800 Greenbelt Road, Greenbelt, MD 20706 (United States); Bradac, Marusa [Department of Physics, University of California, One Shields Avenue, Davis, CA 95616 (United States); Gonzalez, Anthony H.; Chung, Sun Mi [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Massey, Richard [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Zaritsky, Dennis, E-mail: clowe@ohio.edu [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States)

2012-10-20T23:59:59.000Z

370

Compact x-ray source and panel  

SciTech Connect

A compact, self-contained x-ray source, and a compact x-ray source panel having a plurality of such x-ray sources arranged in a preferably broad-area pixelized array. Each x-ray source includes an electron source for producing an electron beam, an x-ray conversion target, and a multilayer insulator separating the electron source and the x-ray conversion target from each other. The multi-layer insulator preferably has a cylindrical configuration with a plurality of alternating insulator and conductor layers surrounding an acceleration channel leading from the electron source to the x-ray conversion target. A power source is connected to each x-ray source of the array to produce an accelerating gradient between the electron source and x-ray conversion target in any one or more of the x-ray sources independent of other x-ray sources in the array, so as to accelerate an electron beam towards the x-ray conversion target. The multilayer insulator enables relatively short separation distances between the electron source and the x-ray conversion target so that a thin panel is possible for compactness. This is due to the ability of the plurality of alternating insulator and conductor layers of the multilayer insulators to resist surface flashover when sufficiently high acceleration energies necessary for x-ray generation are supplied by the power source to the x-ray sources.

Sampayon, Stephen E. (Manteca, CA)

2008-02-12T23:59:59.000Z

371

Energy or Mass and Interaction  

E-Print Network (OSTI)

A review. Problems: 1-Many empirical parameters and large dimension number; 2-Gravitation and Electrodynamics are challenged by dark matter and energy. Energy and nonlinear electrodynamics are fundamental in a unified nonlinear interaction. Nuclear energy appears as nonlinear SU(2) magnetic energy. Gravitation and electromagnetism are unified giving Einstein's equation and a geometric energy momentum tensor. A solution energy in the newtonian limit gives the gravitational constant G. Outside of this limit G is variable. May be interpreted as dark matter or energy. In vacuum, known gravitational solutions are obtained. Electromagnetism is an SU(2) subgroup. A U(1) limit gives Maxwell's equations. Geometric fields determine a generalized Dirac equation and are the germ of quantum physics. Planck's h and of Einstein's c are given by the potential and the metric. Excitations have quanta of charge, flux and spin determining the FQHE. There are only three stable 1/2 spin fermions. Mass is a form of energy. The rest energies of the fermions give the proton/electron mass ratio. Potential excitations have energies equal to the weak boson masses allowing a geometric interpretation of Weinberg's angle. SU(2) gives the anomalous magnetic moments of proton, electron, neutron and generates nuclear range attractive potentials strong enough to produce the binding energies of the deuteron and other nuclides. Lepton and meson masses are due to topological excitations. The geometric mass spectrum is satisfactory. The proton has a triple structure. The alpha constant is a geometric number.

Gustavo R Gonzalez-Martin

2010-07-19T23:59:59.000Z

372

Photon and graviton mass limits  

Science Conference Proceedings (OSTI)

We review past and current studies of possible long-distance, low-frequency deviations from Maxwell electrodynamics and Einstein gravity. Both have passed through three phases: (1) Testing the inverse-square laws of Newton and Coulomb, (2) Seeking a nonzero value for the rest mass of photon or graviton, and (3) Considering more degrees of freedom, allowing mass while preserving gauge or general-coordinate invariance. For electrodynamics there continues to be no sign of any deviation. Since our previous review the lower limit on the photon Compton wavelength (associated with weakening of electromagnetic fields in vacuum over large distance scale) has improved by four orders of magnitude, to about one astronomical unit. Rapid current progress in astronomical observations makes it likely that there will be further advances. These ultimately could yield a bound exceeding galactic dimensions, as has long been contemplated. Meanwhile, for gravity there have been strong arguments about even the concept of a graviton rest mass. At the same time there are striking observations, commonly labeled 'dark matter' and 'dark energy' that some argue imply modified gravity. This makes the questions for gravity much more interesting. For dark matter, which involves increased attraction at large distances, any explanation by modified gravity would be qualitatively different from graviton mass. Because dark energy is associated with reduced attraction at large distances, it might be explained by a graviton-mass-like effect.

Nieto, Michael [Los Alamos National Laboratory; Goldhaber Scharff, Alfred [SUNY

2008-01-01T23:59:59.000Z

373

Gamma-ray Bursts Produced by Mirror Stars  

E-Print Network (OSTI)

I argue that cosmic Gamma-ray Bursts (GRB) may be produced by collapses or mergers of stars made of `mirror' matter. The mirror neutrinos (which are sterile for our matter) produced at these events can oscillate into ordinary neutrinos. The annihilations or decays of the latter create an electron-positron plasma and subsequent relativistic fireball with a very low baryon load needed for GRBs. The concept of mirror matter is able to explain several key problems of modern astrophysics: neutrino anomalies, the missing mass, MACHO microlensing events and GRBs. Thus this concept becomes very appealing and should be considered quite seriously and attentively.

S. Blinnikov

1999-02-21T23:59:59.000Z

374

X-ray tomography of preserved samples from The Geysers scientific corehole  

DOE Green Energy (OSTI)

Approximately 800 ft. of continuous core was recovered from borehole SB-15 D (on unit 15, near the site of the abandoned Geysers Resort) during a recently completed drilling operation funded by the USDOE. Sections of this core were collected at 50 ft intervals for subsequent examination as drilling proceeded. Five foot sections were not removed at the drill site, but were sealed in the innermost sleeve of a triple tube coring system to minimize drying and disturbance of the core. All cores remained sealed and were radiographed within 72 hours of drilling: the five foot core from near 1400 ft. was scanned within 18 hours of drilling. A third generation x-ray scanner, which uses high energy radiation to penetrate the aluminum sleeve and 3.5 inch cores, was used to make preliminary radiographs and to collect multiple views of the sample as the core is rotated in front of the beam. True three dimensional tomographs are then reconstructed from the data. At present, the images have a spatial resolution of approximately 140 micrometers and can resolve contrast differences of 0.2%. The tomographs clearly show differences in lithology with depth in the reservoir. Partially filled fractures, vein selvage and vuggy porosity are all evident in parts of the core. A principle goal of the imaging effort is to help determine the fluid content of the reservoir. Important questions to investigate include water loss during core recovery, infiltration of drilling fluid, and the heterogeneous distribution of pore fluid. Images show that radial gradients in x-ray attenuation commonly occur in jacketed cores. Regions of excess attenuation extend about halfway into the 3.5 in. core, and are probably caused by mud invasion induced by capillarity of the small scale porosity of the graywacke matrix. X-ray measurements will be coordinated with other independent measurements of fluid content underway in separate studies, particularly NMR spectroscopy of frozen ''pressure core'', and compressional velocity and electrical resistivity measurements.

Bonner, B.P.; Roberts, J.J.; Schneberk, D.J.; Marsh, A.; Ruddle, C.; Updike, E.

1995-01-26T23:59:59.000Z

375

Cranking mass parameters for fission  

E-Print Network (OSTI)

A formalism for semi-adiabatic cranking mass parameters is presented. For the fission process of 234U, the time-dependent pairing equations of motion were used to calculate the excitation energy and to extract values of the cranking inertia. A fission barrier is determined by minimizing the action trajectory in a five dimensional configuration space spanned by elongation, necking, deformations of fragments and mass-asymmetry. The deformation energy is computed in the the frame of the microscopic-macroscopic model. The two center shell model with Woods-Saxon potentials is used in this context. Values of the inertia for excited fissioning systems are reported. A dependence between the cranking mass parameters and the intrinsic excitation energy is evidenced.

M. Mirea; R. C. Bobulescu

2009-09-11T23:59:59.000Z

376

Study of Lorentz violation in INTEGRAL Gamma-Ray Bursts  

E-Print Network (OSTI)

We search for possible time lags caused by quantum gravitational (QG) effects using gamma-ray bursts (GRBs) detected by INTEGRAL. The advantage of this satellite is that we have at our disposal the energy and arrival time of every detected single photon, which enhances the precision of the time resolution. We present a new method for seeking time lags in unbinned data using a maximum likelihood method and support our conclusions with Monte Carlo simulations. The analysis of the data yields a mass scale well below the Planck mass whose value may however increase if better statistics of GRBs were available. Furthermore, we disagree with previous studies in which a non-monotonic function of the redshift was used to perform a linear fit.

Raphael Lamon; Nicolas Produit; Frank Steiner

2007-06-27T23:59:59.000Z

377

Mass transport through polycrystalline microstructures  

SciTech Connect

Mass transport properties are important in polycrystalline materials used as protective films. Traditionally, such properties have been studied by examining model polycrystalline structures, such as a regular array of straight grain boundaries. However, these models do not account for a number of features of real grain ensembles, including the grain size distribution and variations in grain shape. In this study, a finite difference scheme is developed to study transient and steady-state mass transport through realistic two dimensional polycrystalline microstructures. Comparisons with the transport properties of traditional model microstructures provide regimes of applicability of such models. The effects of microstructural parameters such as average grain size are examined.

Swiler, T.P.; Holm, E.A.; Young, M.F.; Wright, S.A.

1994-12-31T23:59:59.000Z

378

Alternative Fuels Data Center: Mass Transit  

Alternative Fuels and Advanced Vehicles Data Center (EERE)

Mass Transit to Mass Transit to someone by E-mail Share Alternative Fuels Data Center: Mass Transit on Facebook Tweet about Alternative Fuels Data Center: Mass Transit on Twitter Bookmark Alternative Fuels Data Center: Mass Transit on Google Bookmark Alternative Fuels Data Center: Mass Transit on Delicious Rank Alternative Fuels Data Center: Mass Transit on Digg Find More places to share Alternative Fuels Data Center: Mass Transit on AddThis.com... More in this section... Idle Reduction Parts & Equipment Maintenance Driving Behavior Fleet Rightsizing System Efficiency Ridesharing Mass Transit Active Transit Multi-Modal Transportation Telework Mass Transit Passenger-Miles per Gallon Passenger-miles per gallon (pmpg) is a metric for comparing mass transit and rideshare with typical passenger vehicle travel. Transportation system

379

CORONAL MASS EJECTION MASS, ENERGY, AND FORCE ESTIMATES USING STEREO  

Science Conference Proceedings (OSTI)

Understanding coronal mass ejection (CME) energetics and dynamics has been a long-standing problem, and although previous observational estimates have been made, such studies have been hindered by large uncertainties in CME mass. Here, the two vantage points of the Solar Terrestrial Relations Observatory (STEREO) COR1 and COR2 coronagraphs were used to accurately estimate the mass of the 2008 December 12 CME. Acceleration estimates derived from the position of the CME front in three dimensions were combined with the mass estimates to calculate the magnitude of the kinetic energy and driving force at different stages of the CME evolution. The CME asymptotically approaches a mass of 3.4 {+-} 1.0 Multiplication-Sign 10{sup 15} g beyond {approx}10 R{sub Sun }. The kinetic energy shows an initial rise toward 6.3 {+-} 3.7 Multiplication-Sign 10{sup 29} erg at {approx}3 R{sub Sun }, beyond which it rises steadily to 4.2 {+-} 2.5 Multiplication-Sign 10{sup 30} erg at {approx}18 R{sub Sun }. The dynamics are described by an early phase of strong acceleration, dominated by a force of peak magnitude of 3.4 {+-} 2.2 Multiplication-Sign 10{sup 14} N at {approx}3 R{sub Sun }, after which a force of 3.8 {+-} 5.4 Multiplication-Sign 10{sup 13} N takes effect between {approx}7 and 18 R{sub Sun }. These results are consistent with magnetic (Lorentz) forces acting at heliocentric distances of {approx}Sun }, while solar wind drag forces dominate at larger distances ({approx}>7 R{sub Sun }).

Carley, Eoin P.; Gallagher, Peter T. [Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2 (Ireland); McAteer, R. T. James [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003-8001 (United States)

2012-06-10T23:59:59.000Z

380

Cosmic-ray sum rules  

SciTech Connect

We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays; we show how they can be used to predict the positron fraction at energies not yet explored by current experiments, and to constrain specific models.

Frandsen, Mads T. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Masina, Isabella [Dip. di Fisica dell'Universita di Ferrara and INFN Sez. di Ferrara, Via Saragat 1, I-44100 Ferrara (Italy); CP3-Origins, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Sannino, Francesco [CP3-Origins, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)

2011-06-15T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Time of flight mass spectrometer  

DOE Patents (OSTI)

A time-of-flight mass spectrometer is described in which ions are desorbed from a sample by nuclear fission fragments, such that desorption occurs at the surface of the sample impinged upon by the fission fragments. This configuration allows for the sample to be of any thickness, and eliminates the need for complicated sample preparation.

Ulbricht, Jr., William H. (Arvada, CO)

1984-01-01T23:59:59.000Z

382

Mass modification experiment definition study  

SciTech Connect

This report summarizes an attempt to find an experiment that would test the Haisch, Rueda, and Puthoff (HRP) conjecture that the mass and inertia of a body are induced effects brought about by changes in the quantum-fluctuation energy of the vacuum. It was not possible, however, to identify a definitive experiment. But, it was possible to identify an experiment that might be able to prove or disprove that the inertial mass of a body can be altered by making changes in the vacuum surrounding the body. Other experiments, which do not involve mass modification, but which teach something about the vacuum, were also defined and included in a ranked list of experiments. This report also contains an annotated bibliography. An interesting point raised by this paper is this: We can estimate the `vacuum energy density` to be 10{sup 108} J/cc, and the vacuum mass density to be 10{sup 94} g/cc, much higher numbers than those associated with nuclear energy. Although the field of `electromagnetic fluctuation energy of the vacuum` is admittedly an esoteric, little-understood field, it does seem to have definite potential as an energy source. 47 refs.

Forward, R.L. [Forward Unlimited, Malibu, CA (United States)

1996-12-31T23:59:59.000Z

383

Relation between Kilohertz QPOs and Inferred Mass Accretion Rate in 4 LMXBs  

E-Print Network (OSTI)

I summarize the available RXTE data of the 4 low-mass X-ray binaries (LMXBs) and Atoll sources Aql X-1, 4U 1728-34, 4U 1608-52, and 4U 1636-53. I concentrate on the relation between the frequencies of the quasi-periodic oscillations at kilohertz frequencies (kHz QPOs) and the X-ray flux and colors of these sources. In these 4 sources the kHz QPOs are only observed in a narrow range of spectral states (as defined from the X-ray color-color diagrams). I show that despite its complex dependence upon the X-ray flux, the frequency of the kHz QPOs is monotonically related to the position of the source in the color-color diagram. These findings strengthen the idea that in LMXBs the X-ray flux is not a good indicator of the mass accretion rate, $\\dot M$, and that the observed changes in the frequency of the kHz QPOs in LMXBs are driven by changes in $\\dot M$.

Mariano Mendez

1999-03-31T23:59:59.000Z

384

Comments on the mass of the Photon  

E-Print Network (OSTI)

De Broglie believed that the photon has a mass, a view shared by a few others. Quite recently, the author has argued that the photon has a mass which is consistent with the latest experimental limits. In the present paper we point out that there is experimental evidence for this mass and also give a theoretical demonstration of the photon mass.

Burra G. Sidharth

2006-07-24T23:59:59.000Z

385

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

E-Print Network (OSTI)

Acquisition and interpretation of 3-D seismic data led DeAngelo and Hardage (2001) to describe the channel system in the south central Cut Bank area in Glacier County, Montana. The presence of a low velocity layer called Bentonite was also discovered in the area with the help of well-logs. Bentonite is a volcanic ash, which lies on both sides of the channel system and is absent within the channel. DeAngelo and Hardage (2001) shot a vertical seismic profiling (VSP) survey at well # 54-8 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 for velocity information and estimation of seismic Q using the spectral ratios method (SRM). The SRM theoretically assumes that the propagating signal is a plane seismic wave traveling vertically from one point to another in a homogeneous model. The amplitudes at the start and end points are known and relate to each other with the attenuation coefficient in a frequency range. The relation between the seismic amplitudes at z distance from each other can be expressed as a linear function of frequency after a few modifications. SRM uses the linearity of the logarithmic ratio of the seismic amplitudes over a frequency range. In theory, ratios plotted against a frequency range must produce a flat line. However, in practice, the logarithmic ratios are expected to draw an approximate line (curve), where some of the data points deviate from the origin of the line. Thus fitting a line to the ratios curve and calculating the slope of this curve are necessary. Slope of the curve relates to the seismic attenuation coefficient and further to the seismic Q. The SRM results suggest that Bentonite may have a Q value as low as 5. This highly attenuative and thin (20 to 40 feet throughout the south central Cut Bank Unit) layer alters seismic signals propagating through it. A thorough analysis of the amplitude spectra suggests that seismic signals dramatically lose their energy when they pass through Bentonite. Low energy content of the signals below the Bentonite layer highlights that the recovery of the seismic energy is less likely despite the presence of multiples, which are known to affect the seismic signals constructively. Therefore, separation of reflected events is a greater challenge for the thin reservoir sand units lying underneath the Bentonite layer. Thus the Bentonite layer in the Cut Bank oil field has to be taken seriously and data processing should be done accordingly for better accuracy.

Karakurt, Necdet

2005-12-01T23:59:59.000Z

386

Combustor oscillation attenuation via the control of fuel-supply line dynamics  

DOE Patents (OSTI)

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.

Richards, George A.; Gemmen, Randall S.

1996-12-01T23:59:59.000Z

387

Combustor oscillation attenuation via the control of fuel-supply line dynamics  

DOE Patents (OSTI)

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.

Richards, George A. (Morgantown, WV); Gemmen, Randall S. (Morgantown, WV)

1998-01-01T23:59:59.000Z

388

Combustor oscillation attenuation via the control of fuel-supply line dynamics  

DOE Patents (OSTI)

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.

Richards, G.A.; Gemmen, R.S.

1998-09-22T23:59:59.000Z

389

MassMass transfer andtransfer and separation technologyseparation technology  

E-Print Network (OSTI)

) i fl id t b Massöve small units are needed (H 1 m); 2) corrosive fluids must be handledRaschig ringring packingpacking For Raschig rings with a 1" (inch) di t d h i ht l l t th Picture: WK92 diameter Laboratory tel. 3223 ; ron.zevenhoven@abo.fi RoNz eknikarationste 24302 ochSepa 13.1 Principle of operation

Zevenhoven, Ron

390

MassMass transfer andtransfer and separation technologyseparation technology  

E-Print Network (OSTI)

, spray columns (a) ­ Columns with mechanical agitators or centrifugal effects, for example see section 9.2 24302 ochSepa g g , f p rotating disc contactors (RDC) (b), Kühni columns (c) a b c 4 erföringo a b c-thermal, continuous, steady-state) can be presented as a series of N equilibrium stage contactors Massöve N

Zevenhoven, Ron

391

Delayed X-ray emission from fallback in compact-object mergers  

E-Print Network (OSTI)

When double neutron star or neutron star-black hole binaries merge, the final remnant may comprise a central solar-mass black hole surrounded by a 0.01-0.1 solar masses torus. The subsequent evolution of this disc may be responsible for short gamma-ray bursts (SGRBs). A comparable amount of mass is ejected into eccentric orbits and will eventually fall back to the merger site after approximately 0.01 seconds. In this Paper, we investigate analytically the fate of the fallback matter, which may provide a luminous signal long after the disc is exhausted. We find that matter in the eccentric tail returns at a super-Eddington rate and is eventually (0.1 sec) unable to cool via neutrino emission and accrete all the way to the black hole. Therefore, contrary to previous claims, our analysis suggests that fallback matter is not an efficient source of late time accretion power and is unlikely to cause the late flaring activity observed in SGRB afterglows. The fallback matter rather forms a radiation-driven wind or a bound atmosphere. In both cases, the emitting plasma is very opaque and photons are released with a degraded energy in the X-ray band. We therefore suggest that compact binary mergers could be followed by an "X-ray renaissance", as late as several days to weeks after the merger. This might be observed by the next generation of X-ray detectors.

Elena M. Rossi; Mitchell C. Begelman

2008-08-08T23:59:59.000Z

392

Dark Matter Subhalos and the X-ray Morphology of the Coma Cluster  

E-Print Network (OSTI)

Structure formation models predict that clusters of galaxies contain numerous massive subhalos. The gravity of a subhalo in a cluster compresses the surrounding intracluster gas and enhances its X-ray emission. We present a simple model, which treats subhalos as slow moving and gasless, for computing this effect. Recent weak lensing measurements by Okabe et al. (2010) have determined masses of ~ 10^13 solar masses for three mass concentrations projected within 300 kpc of the center of the Coma cluster, two of which are centered on the giant elliptical galaxies NGC 4889 and NGC 4874. Adopting a smooth spheroidal beta-model for the gas distribution in the unperturbed cluster, we model the effect of these subhalos on the X-ray morphology of the Coma cluster, comparing our results to Chandra and XMM-Newton X-ray data. The agreement between the models and the X-ray morphology of the central Coma cluster is striking. With subhalo parameters from the lensing measurements, the distances of the three subhalos from the...

Andrade-Santos, Felipe; Kraft, Ralph P; Forman, William R; Jones, Christine; Churazov, Eugene; Vikhlinin, Alexey

2013-01-01T23:59:59.000Z

393

Mass profiles of clusters of galaxies : a comparison of X-ray and weak lensing observations  

E-Print Network (OSTI)

Clusters of galaxies are useful probes of cosmology because they are the most massive bound systems and fair representatives of the matter composition of the universe. For clusters to be used as tracers of cosmic evolution, ...

Peng, En-Hsin

2011-01-01T23:59:59.000Z

394

NIST: X-Ray Mass Atten. Coef. - Tissue-Equiv. Gas (Methane)  

Science Conference Proceedings (OSTI)

Table of Contents Back to table 4 Tissue-Equivalent Gas (Methane Based) HTML table format. Energy, ?/?, ? en /?. (MeV), (cm 2 /g), (cm 2 /g). ...

395

NIST: X-Ray Mass Atten. Coef. - Tissue-Equivalent Gas ...  

Science Conference Proceedings (OSTI)

Table of Contents Back to table 4 Tissue-Equivalent Gas (Propane Based) HTML table format. Energy, ?/?, ? en /?. (MeV), (cm 2 /g), (cm 2 /g). ...

396

The gamma-ray lines of radionuclides, ordered by atomic and mass ...  

Science Conference Proceedings (OSTI)

This table contains a complete list of all -/-emitting radionuclides and of all of their .rlines. Additionally it ... The radionuclide data are supplemented by data ...

397

Chest x-Rays | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Chest x-Rays Chest x-Rays Chest x-Rays Chest X-ray B-Reading 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. The B-reading is considered a special reading because doctors who are certified by NIOSH to perform B-readings use a specific protocol to read and record the findings as developed by the International Labour Organization (ILO). The ILO's protocol provides rules for systematically examining the x-ray in a step-by-step method and recording certain abnormalities or changes on the chest x-ray that can be attributable to

398

Gamma ray astrophysics: the EGRET results  

E-Print Network (OSTI)

Cosmic gamma rays provide insight into some of the most dynamic processes in the Universe. At the dawn of a new generation of gamma-ray telescopes, this review summarizes results from the Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory, the principal predecessor mission studying high-energy photons in the 100 MeV energy range. EGRET viewed a gamma-ray sky dominated by prominent emission from the Milky Way, but featuring an array of other sources, including quasars, pulsars, gamma-ray bursts, and many sources that remain unidentified. A central feature of the EGRET results was the high degree of variability seen in many gamma-ray sources, indicative of the powerful forces at work in objects visible to gamma-ray telescopes.

D J Thompson

2008-11-05T23:59:59.000Z

399

High energy Gamma-Ray Bursts as a result of the collapse and total annihilation of neutralino clumps  

E-Print Network (OSTI)

Rare astrophysical events - cosmological gamma-ray bursts with energies over GeV - are considered as an origin of information about some SUSY parameters. The model of generation of the powerful gamma-ray bursts is proposed. According to this model the gamma-ray burst represents as a result of the collapse and the total annihilation of the neutralino clump. About 80 % of the clump mass radiates during about 100 second at the final stage of annihilation. The annihilation spectrum and its characteristic energies are calculated in the framework of Split Higgsino model.

R. S. Pasechnik; V. A. Beylin; V. I. Kuksa; G. M. Vereshkov

2006-02-20T23:59:59.000Z

400

The High Energy Gamma-Ray Background as a Probe of the Dark Matter in the Galactic Halo  

E-Print Network (OSTI)

We present constraints on the density of halo dark matter candidates within the solar circle based on the anisotropy in the high energy gamma-ray background. The known galactic components of the gamma-ray background, in particular the inverse Compton component, have been estimated more accurately. We find the spectrum of the residual emission, after subtracting the galactic component is inconsistent with emission from some of the proposed dark matter candidates. We derive upper limits of 10^8 M_sun for the mass of diffuse gas and 3*10^9 pc^(-3) for the number density of primordial black holes contributing to the gamma-ray background.

R. Chary; E. L. Wright

1998-11-20T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Nuclear Equation of State from Observations of Short Gamma-Ray Burst Remnants  

E-Print Network (OSTI)

The favoured progenitor model for short $\\gamma$-ray bursts (SGRBs) is the merger of two neutron stars that triggers an explosion with a burst of collimated $\\gamma$-rays. Following the initial prompt emission, some SGRBs exhibit a plateau phase in their $X$-ray light curves that indicates additional energy injection from a central engine, believed to be a rapidly rotating, highly magnetised neutron star. The collapse of this `protomagnetar' to a black hole is likely to be responsible for a steep decay in $X$-ray flux observed at the end of the plateau. In this letter, we show that these observations can be used to effectively constrain the equation of state of dense matter. In particular, we show that the known distribution of masses in binary neutron star systems, together with fits to the $X$-ray light curves, provide constraints that exclude the softest and stiffest plausible equations of state. We further illustrate how a future gravitational wave observation with Advanced LIGO/Virgo can place tight constraints on the equation of state, by adding into the picture a measurement of the chirp mass of the SGRB progenitor.

Paul D. Lasky; Brynmor Haskell; Vikram Ravi; Eric J. Howell; David M. Coward

2013-11-06T23:59:59.000Z

402

A near-infrared/optical/X-ray survey in the centre of sigma Orionis  

E-Print Network (OSTI)

Because of the intense brightness of the OB-type multiple star system sigma Ori, the low-mass stellar and substellar populations close to the centre of the very young sigma Orionis cluster is poorly know. I present an IJHKs survey in the cluster centre, able to detect from the massive early-type stars down to cluster members below the deuterium burning mass limit. The near-infrared and optical data have been complemented with X-ray imaging. Ten objects have been found for the first time to display high-energy emission. Previously known stars with clear spectroscopic youth indicators and/or X-ray emission define a clear sequence in the I vs. I-Ks diagram. I have found six new candidate cluster members that follow this sequence. One of them, in the magnitude interval of the brown dwarfs in the cluster, displays X-ray emission and a very red J-Ks colour, indicative of a disc. Other three low-mass stars have excesses in the Ks band as well. The frequency of X-ray emitters in the area is 80+/-20 %. The spatial density of stars is very high, of up to 1.6+/-0.1 arcmin-2. There is no indication of lower abundance of substellar objects in the cluster centre. Finally, I also report two cluster stars with X-ray emission located at only 8000-11000 AU to sigma Ori AB, two sources with peculiar colours and an object with X-ray emission and near-infrared magnitudes similar to those of previously-known substellar objects in the cluster.

José A. Caballero

2007-05-07T23:59:59.000Z

403

Detection and imaging of atmospheric radio flashes from cosmic ray air showers  

E-Print Network (OSTI)

The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >10^20 eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within ~50 Mpc through interactions with the cosmic microwave background. As there are no sufficient powerful accelerators within this distance from the Galaxy, explanations for UHECRs range from unusual astrophysical sources to exotic string physics. Also unclear is whether UHECRs consist of protons, heavy nuclei, neutrinos or gamma-rays. To resolve these questions, larger detectors with higher duty cycles and which combine multiple detection techniques are needed. Radio emission from UHECRs, on the other hand, is unaffected by attenuation, has a high duty cycle, gives calorimetric measurements and provides high directional accuracy. Here we report the detection of radio flashes from cosmic-ray air showers using low-cost digital radio receivers. We show that the radiation can be understood in terms of the geosynchrotron effect. Our results show that it should be possible to determine the nature and composition of UHECRs with combined radio and particle detectors, and to detect the ultrahigh-energy neutrinos expected from flavour mixing.

H. Falcke; W. D. Apel; A. F. Badea

2005-05-18T23:59:59.000Z

404

Imaging of high-energy x-ray emission from cryogenic thermonuclear fuel implosions on the NIF  

Science Conference Proceedings (OSTI)

Accurately assessing and optimizing the implosion performance of inertial confinement fusion capsules is a crucial step to achieving ignition on the NIF. We have applied differential filtering (matched Ross filter pairs) to provide broadband time-integrated absolute x-ray self-emission images of the imploded core of cryogenic layered implosions. This diagnostic measures the temperature- and density-sensitive bremsstrahlung emission and provides estimates of hot spot mass, mix mass, and pressure.

Ma, T.; Izumi, N.; Tommasini, R.; Bradley, D. K.; Bell, P.; Cerjan, C. J.; Dixit, S.; Doeppner, T.; Jones, O.; Landen, O. L.; LePape, S.; Mackinnon, A. J.; Park, H.-S.; Patel, P. K.; Prasad, R. R.; Ralph, J.; Smalyuk, V. A.; Springer, P. T.; Suter, L.; Town, R. P. J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); and others

2012-10-15T23:59:59.000Z

405

Exploring binary-neutron-star-merger scenario of short-gamma-ray bursts by gravitational-wave observation  

E-Print Network (OSTI)

We elucidate the feature of gravitational waves (GWs) from binary neutron star merger collapsing to a black hole by general relativistic simulation. We show that GW spectrum imprints the coalescence dynamics, formation process of disk, equation of state for neutron stars, total masses, and mass ratio. A formation mechanism of the central engine of short $\\gamma$-ray bursts, which are likely to be composed of a black hole and surrounding disk, therefore could be constrained by GW observation.

Kenta Kiuchi; Yuichiro Sekiguchi; Masaru Shibata; Keisuke Taniguchi

2010-02-13T23:59:59.000Z

406

Exposing the dressed quark's mass  

E-Print Network (OSTI)

This snapshot of recent progress in hadron physics made in connection with QCD's Dyson-Schwinger equations includes: a perspective on confinement and dynamical chiral symmetry breaking (DCSB); a pre'cis on the physics of in-hadron condensates; results on the hadron spectrum, including dressed-quark-core masses for the nucleon and Delta, their first radial excitations, and the parity-partners of these states; an illustration of the impact of DCSB on the electromagnetic pion form factor, thereby exemplifying how data can be used to chart the momentum-dependence of the dressed-quark mass function; and a prediction that F_1^{p,d}/F_1^{p,u} passes through zero at Q^2\\approx 5m_N^2 owing to the presence of nonpointlike scalar and axial-vector diquark correlations in the nucleon.

Roberts, H L L; Cloet, I C; Roberts, C D

2010-01-01T23:59:59.000Z

407

Natural attenuation of chlorinated ethenes by anaerobic reductive dechlorination coupled with aerobic cometabolism  

Science Conference Proceedings (OSTI)

Chlorinated solvents and their daughter products are the most common contaminants of groundwater at industrial and military facilities in the United States. Natural attenuation of chlorinated solvents is a promising alternative to traditional pump and treat methods but has not been well understood or widely accepted. This modeling study investigated the ability of TCE to completely degrade under various aquifer conditions and rate order constants. It also examined a case study of a former landfill site at Moody AFB. The author found unusually high flow of ground water by advection or dispersion inhibits the complete degradation of TCE. High concentrations of sulfate or nitrate inhibit the creation of methanogenic conditions and therefore inhibit reductive dechlorination of TCE. He also found an electron donor co-contaminant a critical factor for the complete destruction of TCE because it creates anaerobic conditions. The model illustrated a possible explanation for the lack of down gradient contaminants at the landfill site may be the coupling of reductive dechlorination and cometabolism naturally attenuation the contaminants.

Veerkamp, D.D.

1999-03-01T23:59:59.000Z

408

Analysis of source spectra, attenuation, and site effects from central and eastern United States earthquakes  

Science Conference Proceedings (OSTI)

This report describes the results from three studies of source spectra, attenuation, and site effects of central and eastern United States earthquakes. In the first study source parameter estimates taken from 27 previous studies were combined to test the assumption that the earthquake stress drop is roughly a constant, independent of earthquake size. 200 estimates of stress drop and seismic moment from eastern North American earthquakes were combined. It was found that the estimated stress drop from the 27 studies increases approximately as the square-root of the seismic moment, from about 3 bars at 10{sup 20} dyne-cm to 690 bars at 10{sup 25} dyne-cm. These results do not support the assumption of a constant stress drop when estimating ground motion parameters from eastern North American earthquakes. In the second study, broadband seismograms recorded by the United States National Seismograph Network and cooperating stations have been analysed to determine Q{sub Lg} as a function of frequency in five regions: the northeastern US, southeastern US, central US, northern Basin and Range, and California and western Nevada. In the third study, using spectral analysis, estimates have been made for the anelastic attenuation of four regional phases, and estimates have been made for the source parameters of 27 earthquakes, including the M{sub b} 5.6, 14 April, 1995, West Texas earthquake.

Lindley, G.

1998-02-01T23:59:59.000Z

409

Natural and Enhanced Attenuation of Chlorinated Solvents Using RT3D  

SciTech Connect

RT3D (Reactive Transport in 3-Dimensions) is a reactive transport code that can be applied to model solute fate and transport for many different purposes. This document specifically addresses application of RT3D for modeling related to evaluation and implementation of Monitored Natural Attenuation (MNA). Selection of MNA as a remedy requires an evaluation process to demonstrate that MNA will meet the remediation goals. The U.S. EPA, through the Office of Solid Waste and Emergency Response (OSWER) Directive 9200.4?17P, provides the regulatory context for the evaluation and implementation of MNA. In a complementary fashion, the context for using fate and transport modeling as part of MNA evaluation is described in the EPA?s technical protocol for chlorinated solvent MNA, the Scenarios Evaluation Tool for Chlorinated Solvent MNA, and in this document. The intent of this document is to describe (1) the context for applying RT3D for chlorinated solvent MNA and (2) the attenuation processes represented in RT3D, (3) dechlorination reactions that may occur, and (4) the general approach for using RT3D reaction modules (including a summary of the RT3D reaction modules that are available) to model fate and transport of chlorinated solvents as part of MNA or for combinations of MNA and selected types of active remediation.

Johnson, Christian D.; Truex, Michael J.; Clement, T P.

2006-07-25T23:59:59.000Z

410

CHARACTERIZATION AND MONITORING OF NATURAL ATTENUATION OF CHLORINATED SOLVENTS IN GROUNDWATER: A SYSTEMS APPROACH  

SciTech Connect

The objective of this document is to examine the use of a phased approach to characterizing and monitoring (C&M) natural attenuation processes and enhanced attenuation processes and to identify promising tools and techniques by which to accomplish the C&M. We will investigate developing techniques, such as molecular-based assessment tools, and existing tools that traditionally have not been used for monitoring the performance of environmental remediation technologies. Case studies will be used to provide examples of how non-traditional methods are being employed as characterization and monitoring tools to support MNA and EA. The document is not focused on a specific group of readers but rather is broadly directed with the intent that readers may gain information useful to their purposes. Thus, regulators may see some future characterization and monitoring techniques; end users may find novel ways to make MNA or EA more effective or efficient at their site; researchers may identify new areas for development or new and better combinations of existing methods. One consequence of this broad approach is that some readers may find certain sections either too rudimentary or too advanced for their needs. Hopefully, all will be able to use at least some of the document.

Looney, B; Michael Heitkamp, M; Gary Wein (NOEMAIL), G; Christopher Bagwell, C; Karen Vangelas, K; Karen-M Adams, K; Tyler Gilmore; Norman Cutshall; David Major; Mike Truex; Todd Wiedemeier; Francis H. Chapelle; Tom Early; Jody Waugh; David Peterson; Mark Ankeny; Claire H. Sink

2006-08-10T23:59:59.000Z

411

Speciation and Attenuation of Arsenic and Selenium at Coal Combustion By-Product Management Facilities  

Science Conference Proceedings (OSTI)

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.

K. Ladwig

2005-12-31T23:59:59.000Z

412

Stellar Sources of Gamma-ray Bursts  

E-Print Network (OSTI)

Correlation analysis of Swift gamma-ray burst coordinates and nearby star locations (catalog Gliese) reveals 4 coincidences with good angular accuracy. The random probability is 4\\times 10^{-5}, so evidencing that coincident stars are indeed gamma-ray burst sources. Some additional search of stellar gamma-ray bursts is discussed.

Luchkov, B I

2011-01-01T23:59:59.000Z

413

Fermi Observations of Gamma?ray Bursts  

Science Conference Proceedings (OSTI)

The gamma?ray emission mechanism of Gamma?ray bursts (GRBs) are still unknown. Fermi Gamma?ray Space Telescope successfully detected high?energy (> 100 MeV) emission from 17 GRBs since its launch. Fermi revealed the distinct temporal behaviors and extra spectral component from high?energy emission. These new observational results are driving many theoretical implications

Masanori Ohno; The Fermi?LAT collaborations; The GBM collaborations

2010-01-01T23:59:59.000Z

414

Cryotomography x-ray microscopy state  

Science Conference Proceedings (OSTI)

An x-ray microscope stage enables alignment of a sample about a rotation axis to enable three dimensional tomographic imaging of the sample using an x-ray microscope. A heat exchanger assembly provides cooled gas to a sample during x-ray microscopic imaging.

Le Gros, Mark (Berkeley, CA); Larabell, Carolyn A. (Berkeley, CA)

2010-10-26T23:59:59.000Z

415

Multifrequency Observations of Gamma-Ray Burst  

E-Print Network (OSTI)

Neither a flaring nor a quiescent counterpart to a gamma-ray burst has yet been convincingly identified at any wavelength region. The present status of the search for counterparts of classical gamma-ray bursts is given. Particular emphasis is put on the search for flaring counterparts, i.e. emission during or shortly after the gamma-ray emission.

J. Greiner

1995-10-04T23:59:59.000Z

416

Graphene, neutrino mass and oscillation  

E-Print Network (OSTI)

A resolution of the Abraham-Minkowski dilemma is presented that other constant velocities can play the role of c in the theory of relativity. For example, in 2005 electrons of graphene were discovered to behave as if the coefficient is a Fermi velocity. Then we propose a conjecture for neutrinos to avoid the contradiction among two-component theory, negative rest mass-square and oscillation.

Z. Y. Wang

2009-09-10T23:59:59.000Z

417

Microgap x-ray detector  

DOE Patents (OSTI)

An x-ray detector which provides for the conversion of x-ray photons into photoelectrons and subsequent amplification of these photoelectrons through the generation of electron avalanches in a thin gas-filled region subject to a high electric potential. The detector comprises a cathode (photocathode) and an anode separated by the thin, gas-filled region. The cathode may comprise a substrate, such a beryllium, coated with a layer of high atomic number material, such as gold, while the anode can be a single conducting plane of material, such as gold, or a plane of resistive material, such as chromium/silicon monoxide, or multiple areas of conductive or resistive material, mounted on a substrate composed of glass, plastic or ceramic. The charge collected from each electron avalanche by the anode is passed through processing electronics to a point of use, such as an oscilloscope.

Wuest, Craig R. (Danville, CA); Bionta, Richard M. (Livermore, CA); Ables, Elden (Livermore, CA)

1994-01-01T23:59:59.000Z

418

X-RAY SUBSTRUCTURE STUDIES OF FOUR GALAXY CLUSTERS USING XMM-NEWTON DATA  

SciTech Connect

Mahdavi et al. find that the degree of agreement between weak lensing and X-ray mass measurements is a function of cluster radius. Numerical simulations also point out that X-ray mass proxies do not work equally well at all radii. The origin of the effect is thought to be associated with cluster mergers. Recent work presenting the cluster maps showed an ability of X-ray maps to reveal and study cluster mergers in detail. Here, we present a first attempt to use the study of substructure in assessing the systematics of the hydrostatic mass measurements using two-dimensional (2D) X-ray diagnostics. The temperature map is uniquely able to identify the substructure in an almost relaxed cluster which would be unnoticed in the intracluster medium electron number density and pressure maps. We describe the radial fluctuations in the 2D maps by a cumulative/differential scatter profile relative to the mean profile within/at a given radius. The amplitude indicates {approx}10% fluctuations in the temperature, electron number density, and entropy maps, and {approx}15% fluctuations in the pressure map. The amplitude of and the discontinuity in the scatter complement 2D substructure diagnostics, e.g., indicating the most disturbed radial range. There is a tantalizing link between the substructure identified using the scatter of the entropy and pressure fluctuations and the hydrostatic mass bias relative to the expected mass based on the M-Y{sub X} and M-M{sub gas} relations particularly at r{sub 500}. XMM-Newton observations with {approx}120,000 source photons from the cluster are sufficient to apply our substructure diagnostics via the spectrally measured 2D temperature, electron number density, entropy, and pressure maps.

Zhang Yuying; Reiprich, Thomas H.; Hudson, Daniel S. [Argelander Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, 53121 Bonn (Germany); Finoguenov, Alexis [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, 85748 Garching (Germany); Sarazin, Craig L. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904 (United States)

2009-07-10T23:59:59.000Z

419

A semiempirical linear model of indirect, flat-panel x-ray detectors  

Science Conference Proceedings (OSTI)

Purpose: It is important to understand signal and noise transfer in the indirect, flat-panel x-ray detector when developing and optimizing imaging systems. For optimization where simulating images is necessary, this study introduces a semiempirical model to simulate projection images with user-defined x-ray fluence interaction. Methods: The signal and noise transfer in the indirect, flat-panel x-ray detectors is characterized by statistics consistent with energy-integration of x-ray photons. For an incident x-ray spectrum, x-ray photons are attenuated and absorbed in the x-ray scintillator to produce light photons, which are coupled to photodiodes for signal readout. The signal mean and variance are linearly related to the energy-integrated x-ray spectrum by empirically determined factors. With the known first- and second-order statistics, images can be simulated by incorporating multipixel signal statistics and the modulation transfer function of the imaging system. To estimate the semiempirical input to this model, 500 projection images (using an indirect, flat-panel x-ray detector in the breast CT system) were acquired with 50-100 kilovolt (kV) x-ray spectra filtered with 0.1-mm tin (Sn), 0.2-mm copper (Cu), 1.5-mm aluminum (Al), or 0.05-mm silver (Ag). The signal mean and variance of each detector element and the noise power spectra (NPS) were calculated and incorporated into this model for accuracy. Additionally, the modulation transfer function of the detector system was physically measured and incorporated in the image simulation steps. For validation purposes, simulated and measured projection images of air scans were compared using 40 kV/0.1-mm Sn, 65 kV/0.2-mm Cu, 85 kV/1.5-mm Al, and 95 kV/0.05-mm Ag. Results: The linear relationship between the measured signal statistics and the energy-integrated x-ray spectrum was confirmed and incorporated into the model. The signal mean and variance factors were linearly related to kV for each filter material (r{sup 2} of signal mean to kV: 0.91, 0.93, 0.86, and 0.99 for 0.1-mm Sn, 0.2-mm Cu, 1.5-mm Al, and 0.05-mm Ag, respectively; r{sup 2} of signal variance to kV: 0.99 for all four filters). The comparison of the signal and noise (mean, variance, and NPS) between the simulated and measured air scan images suggested that this model was reasonable in predicting accurate signal statistics of air scan images using absolute percent error. Overall, the model was found to be accurate in estimating signal statistics and spatial correlation between the detector elements of the images acquired with indirect, flat-panel x-ray detectors. Conclusions: The semiempirical linear model of the indirect, flat-panel x-ray detectors was described and validated with images of air scans. The model was found to be a useful tool in understanding the signal and noise transfer within indirect, flat-panel x-ray detector systems.

Huang, Shih-Ying; Yang Kai; Abbey, Craig K.; Boone, John M. [Department of Biomedical Engineering, University of California, Davis, California, One Shields Avenue, Davis, California 95616 (United States) and Department of Radiology, University of California, Davis, Medical Center, 4860 Y Street, Ambulatory Care Center Suite 0505, Sacramento, California 95817 (United States); Department of Radiology, University of California, Davis, Medical Center, 4860 Y Street, Ambulatory Care Center Suite 0505, Sacramento, California 95817 (United States); Department of Psychological and Brain Sciences, University of California, Santa Barbara, California 92106 (United States); Department of Biomedical Engineering, University of California, Davis, California, One Shields Avenue, Davis, California 95616 (United States) and Department of Radiology, University of California, Davis, Medical Center, 4860 Y Street, Ambulatory Care Center Suite 3100, Sacramento, California 95817 (United States)

2012-04-15T23:59:59.000Z

420

Pair-production opacity at high and very-high gamma-ray energies  

E-Print Network (OSTI)

The propagation of high energy (HE, $E_\\gamma>100$ MeV) and very high-energy gamma-rays (VHE, $E_\\gamma>100$ GeV) in the extra-galactic photon field leads to pair-production and consequently energy- and distance-dependent attenuation of the primary intensity. The spectroscopy of an increasing number of extra-galactic objects at HE and VHE energies has demonstrated indeed the presence of such an attenuation which in turn has been used to constrain the photon density in the medium. At large optical depth ($\\tau\\gtrsim 2$) potential modifications of pair-production due to competing but rare processes (as, e.g., the presence of sub-neV axion-like particle) may be found. Indications for a pair-production anomaly have previously been found with VHE-spectra. Here, we present further indications (at the level of $3.68 \\sigma$) for a reduced optical depth at high energies from an analysis of Fermi-\\textit{LAT} data.

Dieter Horns; Manuel Meyer

2013-09-16T23:59:59.000Z

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Scaling relations and mass bias in hydrodynamical f(R) gravity simulations of galaxy clusters  

E-Print Network (OSTI)

We investigate the impact of chameleon-type f(R) gravity models on the properties of galaxy clusters and groups. Our f(R) simulations follow for the first time also the hydrodynamics of the intracluster and intragroup medium. This allows us to assess how f(R) gravity alters the X-ray scaling relations of clusters and how hydrostatic and dynamical mass estimates are biased when modifications of gravity are ignored in their determination. We find that velocity dispersions and intracluster medium temperatures are both increased by up to 1/3 in f(R) gravity in low-mass halos, while the difference disappears in massive objects. The mass scale of the transition depends on the background value f_R0 of the scalar degree of freedom. These changes in temperature and velocity dispersion alter the mass-temperature and X-ray luminosity-temperature scaling relations and bias dynamical and hydrostatic mass estimates that do not explicitly account for modified gravity towards higher values. Recently, a relative enhancement o...

,

2013-01-01T23:59:59.000Z

422

Spectral Lags of Gamma-Ray Bursts from Primordial Black Hole (PBH) Evaporations  

E-Print Network (OSTI)

Primordial Black Holes (PBHs), which may have been created in the early Universe, are predicted to be detectable by their Hawking radiation. PBHs with an initial mass of 5.0 * 10^14 g should be expiring today with a burst of high energy particles. Evaporating PBHs in the solar neighborhood are candidate Gamma-Ray Bursts (GRBs) progenitors. We propose spectral lag, which is the temporal delay between the high energy photon pulse and the low energy photon pulse, as a possible method to detect PBH evaporation events with the Fermi Gamma-ray Space Telescope Observatory.

T. N. Ukwatta; J. H. MacGibbon; W. C. Parke; K. S. Dhuga; A. Eskandarian; N. Gehrels; L. Maximon; D. C. Morris

2009-01-05T23:59:59.000Z

423

Hadron Mass Extraction from Lattice QCD  

E-Print Network (OSTI)

The extraction of quantities from lattice QCD calculations at realistic quark masses is of considerable importance. Whilst physical quark masses are some way off, the recent advances in the calculation of hadron masses within full QCD now invite improved extrapolation methods. We show that, provided the correct chiral behaviour of QCD is respected in the extrapolation to realistic quark masses, one can indeed obtain a fairly reliable determination of masses, the sigma commutator and the J parameter. We summarise these findings by presenting the nonanalytic behaviour of nucleon and rho masses in the standard Edinburgh plot.

S. V. Wright; D. B. Leinweber; A. W. Thomas; K. Tsushima

2001-11-27T23:59:59.000Z

424

Constraints on dark matter annihilations from diffuse gamma-ray emission in the Galaxy  

E-Print Network (OSTI)

Recent advances in gamma-ray cosmic ray, infrared and radio astronomy have allowed us to develop a significantly better understanding of the galactic medium properties in the last few years. In this work using the DRAGON code, that numerically solves the CR propagation equation and calculating gamma-ray emissivities in a 2-dimensional grid enclosing the Galaxy, we study in a self consistent manner models for the galactic diffuse gamma-ray emission. Our models are cross-checked to both the available CR and gamma-ray data. We address the extend to which dark matter annihilations in the Galaxy can contribute to the diffuse gamma-ray flux towards different directions on the sky. Moreover we discuss the impact that astrophysical uncertainties of non DM nature, have on the derived gamma-ray limits. Such uncertainties are related to the diffusion properties on the Galaxy, the interstellar gas and the interstellar radiation field energy densities. Light ~10 GeV dark matter annihilating dominantly to hadrons is more strongly constrained by gamma-ray observations towards the inner parts of the Galaxy and influenced the most by assumptions of the gas distribution; while TeV scale DM annihilating dominantly to leptons has its tightest constraints from observations towards the galactic center avoiding the galactic disk plane, with the main astrophysical uncertainty being the radiation field energy density. In addition, we present a method of deriving constraints on the dark matter distribution profile from the diffuse gamma-ray spectra. These results critically depend on the assumed mass of the dark matter particles and the type of its end annihilation products.

Maryam Tavakoli; Ilias Cholis; Carmelo Evoli; Piero Ullio

2013-08-19T23:59:59.000Z

425

The Diverse Environments of Gamma-Ray Bursts  

E-Print Network (OSTI)

of a Very Bright Gamma- Ray Burst in a Galactic Halo 3.1Galaxies of Dark Gamma-Ray Bursts: Observational Constraints1.3 Gamma-Ray Burst Classi?cation . . . . . . 1.4 Gamma-Ray

Perley, Daniel Alan

2011-01-01T23:59:59.000Z

426

The Ulysses Catalog of Solar Hard X-Ray Flares  

E-Print Network (OSTI)

its Solar X-ray/Cosmic Gamma-Ray Burst Experiment (GRB) hasInstrument The Ulysses Gamma-Ray Burst (GRB) instrument, hasrate due to a cosmic gamma-ray burst or a solar ?are, but we

Tranquille, C.; Hurley, K.; Hudson, H. S.

2009-01-01T23:59:59.000Z

427

APS Bending Magnet X-rays and  

NLE Websites -- All DOE Office Websites (Extended Search)

Irradiation of Nd-Fe-B Permanent Magnets with Irradiation of Nd-Fe-B Permanent Magnets with APS Bending Magnet X-rays and 60 Co γ-rays J. Alderman and P.K. Job APS Operations Division Advanced Photon Source J. Puhl Ionizing Radiation Division National Institute of Standards and Technology June 2000 Table of Contents Introduction Radiation-Induced Demagnetization of Permanent Magnets Resources Required γ-ray Irradiation Results and Analysis of γ-ray Irradiation X-ray Irradiation Results and Analysis of X-ray Irradiation Summary and Conclusions Acknowledgements References Tables and Figures Introduction The Advanced Photon Source (APS), as well as other third-generation synchrotron light sources, uses permanent magnets in the insertion devices to produce x-rays for scientific

428

Discrete symmetries and neutrino masses  

SciTech Connect

We constructed a model of neutrino masses using Froggatt-Nielsen mechanism with U(1)xZ{sub 3}xZ{sub 2} flavor symmetry. The model predicts that (2/3)m{sub 2}/m{sub 3}{approx}{radical}(2)sin{theta}{sub 13} at lepton number violating scale M{sub 1}. It is shown that the small values for m{sub 2}/m{sub 3} and sin{theta}{sub 13} are consequences of breaking discrete symmetries.

Siyeon, Kim [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

2005-02-01T23:59:59.000Z

429

The Neutron Stars of Soft X-Ray Transients  

E-Print Network (OSTI)

Soft X-ray Transients (SXRTs) have long been suspected to contain old, weakly magnetic neutron stars that have been spun up by accretion torques. After reviewing their observational properties, we analyse the different regimes that likely characterise the neutron stars in these systems across the very large range of mass inflow rates, from the peak of the outbursts to the quiescent emission. While it is clear that close to the outburst maxima accretion onto the neutron star surface takes place, as the mass inflow rate decreases, accretion might stop at the magnetospheric boundary because of the centrifugal barrier provided by the neutron star. For low enough mass inflow rates (and sufficiently short rotation periods), the radio pulsar mechanism might turn on and sweep the inflowing matter away. The origin of the quiescent emission, observed in a number of SXRTs at a level of ~10^(32)-10^(33) erg/s, plays a crucial role in constraining the neutron star magnetic field and spin period. Accretion onto the neutron...

Campana, S; Mereghetti, S; Stella, L; Tavani, M

1998-01-01T23:59:59.000Z

430

Quark masses : an environmental impact statement  

E-Print Network (OSTI)

We investigate how the requirement that organic chemistry be possible constrains the values of the quark masses. Specifically, we choose a slice through the parameter space of the Standard Model in which quark masses vary ...

Kimchi, Itamar

2008-01-01T23:59:59.000Z

431

A Global Diagnostic of Interocean Mass Transfers  

Science Conference Proceedings (OSTI)

An objective and quantitative estimate of all mean annual interocean mass transfers together with a picture of the associated mean pathways is presented. The global ocean circulation transfers mass, heat, and salinity between the various ocean ...

B. Blanke; S. Speich; G. Madec; K. Döös

2001-06-01T23:59:59.000Z

432

What are the exact relative masses of...  

NLE Websites -- All DOE Office Websites (Extended Search)

to one another, it doesn't tell you what the actual masses of these particles are. In kilograms, the masses are: Neutron 1.6749286*10-27 kg Proton 1.6726231*10-27 kg Electron ...

433

W Boson Mass Working Group Report  

SciTech Connect

The W boson mass working group discussed the current status of the W boson mass measurement and the prospects for improving on LEP and Tevatron measurements at the LHC.

Kilgore, W.; Kilgore, W.

2010-06-14T23:59:59.000Z

434

Analysis of hard X-ray eclipse in SS433 from INTEGRAL observations  

E-Print Network (OSTI)

The analysis of hard X-ray INTEGRAL observations (2003-2008) of superaccreting galactic microquasar SS433 at precessional phases of the source with the maximum disk opening angle is carried out. It is found that the shape and width of the primary X-ray eclipse is strongly variable suggesting additional absorption in dense stellar wind and gas outflows from the optical A7I-component and the wind-wind collision region. The independence of the observed hard X-ray spectrum on the accretion disk precessional phase suggests that hard X-ray emission (20-100 keV) is formed in an extended, hot, quasi-isothermal corona, probably heated by interaction of relativistic jet with inhomogeneous wind outflow from the precessing supercritical accretion disk. A joint modeling of X-ray eclipsing and precessional hard X-ray variability of SS433 revealed by INTEGRAL by a geometrical model suggests the binary mass ratio $q=m_x/m_v\\simeq 0.25\\div 0.5$. The absolute minimum of joint orbital and precessional $\\chi^2$ residuals is reac...

Cherepashchuk, A M; Postnov, K A; Antokhina, E A; Molkov, S V

2009-01-01T23:59:59.000Z

435

BROADBAND SPECTRAL ANALYSIS OF THE GALACTIC RIDGE X-RAY EMISSION  

SciTech Connect

Detailed spectral analysis of the Galactic X-ray background emission, or the Galactic Ridge X-ray Emission (GRXE), is presented. To study the origin of the emission, broadband and high-quality GRXE spectra were produced from 18 pointing observations with Suzaku in the Galactic bulge region, with a total exposure of 1 Ms. The spectra were successfully fitted by a sum of two major spectral components: a spectral model of magnetic accreting white dwarfs with a mass of 0.66{sup +0.09}{sub -0.07} M{sub Sun} and a softer optically thin thermal emission with a plasma temperature of 1.2-1.5 keV that is attributable to coronal X-ray sources. When combined with previous studies that employed high spatial resolution of the Chandra satellite, the present spectroscopic result gives stronger support to the scenario that the GRXE is essentially an assembly of numerous discrete faint X-ray stars. The detected GRXE flux in the hard X-ray band was used to estimate the number density of the unresolved hard X-ray sources. When integrated over a luminosity range of {approx}10{sup 30}-10{sup 34} erg s{sup -1}, the result is consistent with a value that was reported previously by directly resolving faint point sources.

Yuasa, Takayuki; Makishima, Kazuo; Nakazawa, Kazuhiro, E-mail: yuasa@astro.isas.jaxa.jp [Department of Physics, School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan)

2012-07-10T23:59:59.000Z

436

A CATALOG OF CHANDRA X-RAY SOURCES IN THE CARINA NEBULA  

Science Conference Proceedings (OSTI)

We present a catalog of {approx}14,000 X-ray sources observed by the ACIS instrument on the Chandra X-ray Observatory within a 1.42 deg{sup 2} survey of the Great Nebula in Carina, known as the Chandra Carina Complex Project (CCCP). This study appears in a special issue devoted to the CCCP. Here, we describe the data reduction and analysis procedures performed on the X-ray observations, including calibration and cleaning of the X-ray event data, point-source detection, and source extraction. The catalog appears to be complete across most of the field to an absorption-corrected total-band luminosity of {approx}10{sup 30.7} erg s{sup -1} for a typical low-mass pre-main-sequence star. Counterparts to the X-ray sources are identified in a variety of visual, near-infrared, and mid-infrared surveys. The X-ray and infrared source properties presented here form the basis of many CCCP studies of the young stellar populations in Carina.

Broos, Patrick S.; Townsley, Leisa K.; Feigelson, Eric D.; Getman, Konstantin V.; Garmire, Gordon P. [Department of Astronomy and Astrophysics, 525 Davey Laboratory, Pennsylvania State University, University Park, PA 16802 (United States); Preibisch, Thomas [Universitaets-Sternwarte, Ludwig-Maximilians-Universitaet, Scheinerstr. 1, 81679 Muenchen (Germany); Smith, Nathan [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Babler, Brian L.; Meade, Marilyn R. [Department of Astronomy, University of Wisconsin, 475 N. Charter St., Madison, WI 53706 (United States); Hodgkin, Simon; Irwin, Mike; Lewis, Jim [Cambridge Astronomical Survey Unit, Institute of Astronomy, Madingley Road, Cambridge CB3 (United Kingdom); Indebetouw, Remy; Majewski, Steven R. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); King, Robert R.; McCaughrean, Mark J. [Astrophysics Group, College of Engineering, Mathematics, and Physical Sciences, University of Exeter, Exeter EX4 4QL (United Kingdom); Zinnecker, Hans, E-mail: patb@astro.psu.edu [Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam (Germany)

2011-05-01T23:59:59.000Z

437

Accelerator Mass Spectrometry: Extreme Sensitivity in Biological ...  

THE LLNL TECHNOLOGY COMPANY PRODUCT 24 Partnering Today: Technology Transfer Highlights Accelerator Mass Spectrometry: Extreme Sensitivity in Biological Research

438

The conservation of mass-moment parameters  

E-Print Network (OSTI)

In this paper we study a concept of mass-moment parameter which is the generalization of the mass and the moments of inertia of a continuous media. We shall present some interesting kinematical results in the hypothesis that a set of mass-moment parameters are conserved in a motion of a continuous media.

Dan Comanescu

2007-02-16T23:59:59.000Z

439

Advanced Mass Spectrometers for Hydrogen Isotope Analyses  

DOE Green Energy (OSTI)

This report is a summary of the results of a joint Savannah River Laboratory (SRL) - Savannah River Plant (SRP) ''Hydrogen Isotope Mass Spectrometer Evaluation Program''. The program was undertaken to evaluate two prototype hydrogen isotope mass spectrometers and obtain sufficient data to permit SRP personnel to specify the mass spectrometers to replace obsolete instruments.

Chastagner, P.

2001-08-01T23:59:59.000Z

440

Mass Transportation on the Earth Ludovic Rifford  

E-Print Network (OSTI)

Mass Transportation on the Earth Ludovic Rifford Universit´e Nice - Sophia Antipolis & Institut Mass Transportation on the Earth #12;The framework Let M be a smooth connected compact surface in Rn of the lengths of the curves (drawn on M) joining x to y. Ludovic Rifford Mass Transportation on the Earth #12

Rifford, Ludovic

Note: This page contains sample records for the topic "ray mass attenuation" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

Mass Transportation on the Earth Ludovic Rifford  

E-Print Network (OSTI)

Mass Transportation on the Earth Ludovic Rifford Universit´e de Nice - Sophia Antipolis Ludovic Rifford Mass Transportation on the Earth #12;The framework Let M be a smooth connected compact surface), as the minimum of the lengths of the curves (drawn on M) joining x to y. Ludovic Rifford Mass Transportation

Rifford, Ludovic

442

Mass Transportation on the Earth Ludovic Rifford  

E-Print Network (OSTI)

Mass Transportation on the Earth Ludovic Rifford Universit´e de Nice - Sophia Antipolis & Institut Universitaire de France UPV/EHU Ludovic Rifford Mass Transportation on the Earth #12;The framework Let M Rifford Mass Transportation on the Earth #12;Transport maps Let µ0 and µ1 be probability measures on M. We

Rifford, Ludovic

443

Eliminating the low-mass axigluon window  

E-Print Network (OSTI)

Using recent collider data, especially on the hadronic width the Z0, we exclude axigluons in the currently allowed low-mass window, namely axigluons in the mass range 50 GeV < M_A < 120 GeV. Combined with hadron collider data from di-jet production, axigluons with masses below roughly 1 TeV are now completely excluded.

M. A. Doncheski; R. W. Robinett

1998-04-03T23:59:59.000Z

444

Gamma Ray Burst Central Engines  

E-Print Network (OSTI)

I review aspects of the theory of long-duration gamma-ray burst (GRB) central engines. I focus on the requirements of any model; these include the angular momentum of the progenitor, the power, Lorentz factor, asymmetry, and duration of the flow, and both the association and the non-association with bright supernovae. I compare and contrast the collapsar and millisecond proto-magnetar models in light of these requirements. The ability of the latter model to produce a flow with Lorentz factor ~100 while simultaneously maintaining a kinetic luminosity of ~10^50 ergs/s for a timescale of ~10-100 s is emphasized.

Todd A. Thompson

2008-07-04T23:59:59.000Z

445

High-energy Cosmic Rays  

E-Print Network (OSTI)

After a brief review of galactic cosmic rays in the GeV to TeV energy range, we describe some current problems of interest for particles of very high energy. Particularly interesting are two features of the spectrum, the `knee' above $10^{15}$ eV and the `ankle' above $10^{18}$ eV. An important question is whether the highest energy particles are of extra-galactic origin and, if so, at what energy the transition occurs. A theme common to all energy ranges is use of nuclear abundances as a tool for understanding the origin of the cosmic radiation.

Thomas K. Gaisser; Todor Stanev

2005-10-11T23:59:59.000Z