Sample records for gamma parameter corresponds

  1. Deconvolution of mixed gamma emitters using peak parameters

    SciTech Connect (OSTI)

    Gadd, Milan S [Los Alamos National Laboratory; Garcia, Francisco [Los Alamos National Laboratory; Magadalena, Vigil M [Los Alamos National Laboratory

    2011-01-14T23:59:59.000Z

    When evaluating samples containing mixtures of nuclides using gamma spectroscopy the situation sometimes arises where the nuclides present have photon emissions that cannot be resolved by the detector. An example of this is mixtures of {sup 241}Am and plutonium that have L x-ray emissions with slightly different energies which cannot be resolved using a high-purity germanium detector. It is possible to deconvolute the americium L x-rays from those plutonium based on the {sup 241}Am 59.54 keV photon. However, this requires accurate knowledge of the relative emission yields. Also, it often results in high uncertainties in the plutonium activity estimate due to the americium yields being approximately an order of magnitude greater than those for plutonium. In this work, an alternative method of determining the relative fraction of plutonium in mixtures of {sup 241}Am and {sup 239}Pu based on L x-ray peak location and shape parameters is investigated. The sensitivity and accuracy of the peak parameter method is compared to that for conventional peak decovolution.

  2. A study of the performance parameters of the High Altitude Gamma Ray (HAGAR) telescope system at Ladakh in India

    E-Print Network [OSTI]

    Shyamasundar, R.K.

    results of Monte Carlo simulations for the High Altitude Gamma Ray (HAGAR) telescope array which detects High Altitude GAmma Ray (HAGAR) telescope system is designed to detect very high energy gamma rays fromA study of the performance parameters of the High Altitude Gamma Ray (HAGAR) telescope system

  3. Determination of the relativistic parameter gamma using very long baseline interferometry

    E-Print Network [OSTI]

    S. B. Lambert; C. Le Poncin-Lafitte

    2009-03-09T23:59:59.000Z

    Relativistic bending in the vicinity of a massive body is characterized only by the post-Newtonian parameter $\\gamma$ within the standard parameterized post-Newtonian formalism, which is unity in General Relativity. Aiming at estimating this parameter, we use very long baseline interferometry (VLBI) to measure the gravitational deflection of radio waves emitted by distant compact radio sources, by Solar System bodies. We analyze geodetic VLBI observations recorded since 1979. We compare estimates of $\\gamma$ and errors obtained using various analysis schemes including global estimations over several time spans and with various Sun elongation cut-off angles, and analysis of radio source coordinate time series. We arrive at the conclusion that the relativistic parameter $\\gamma$ cannot be estimated at better than $2\\times10^{-4}$. The main factor of limitation is the uncertainty in the determination of (global or session-wise) radio source coordinates. A sum of various instrumental and modeling errors and analysis strategy defects, that cannot be decorrelated and corrected yet, is at the origin of the limitating noise.

  4. Parameters of the prompt gamma-ray burst emission estimated with the opening angle of jets

    E-Print Network [OSTI]

    B. -B. Zhang; Y. -P. Qin

    2006-02-04T23:59:59.000Z

    We present in this paper an approach to estimate the initial Lorentz factor of gamma-ray bursts (GRBs) without referring to the delayed emission of the early afterglow. Under the assumption that the afterglow of the bursts concerned occurs well before the prompt emission dies away, the Lorentz factor measured at the time when the duration of the prompt emission is ended could be estimated by applying the well-known relations of GRB jets. With the concept of the efficiency for converting the explosion energy to radiation, this Lorentz factor can be related to the initial Lorentz factor of the source. The corresponding rest frame peak energy can accordingly be calculated. Applying this method, we estimate the initial Lorentz factor of the bulk motion and the corresponding rest frame spectral peak energy of GRBs for a new sample where the redshift and the break time in the afterglow are known. Our analysis shows that, in the circumstances, the initial Lorentz factor of the sample would peak at 200 and would be distributed mainly within $(100,400)$, and the peak of the distribution of the corresponding rest frame peak energy would be $0.8keV$ and its main region would be $(0.3keV,3keV)$.

  5. Toward a better understanding of the gamma index: Investigation of parameters with a surface-based distance method

    SciTech Connect (OSTI)

    Li Heng; Dong Lei; Zhang Lifei; Yang, James N.; Gillin, Michael T.; Zhu, X. Ronald [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2011-12-15T23:59:59.000Z

    Purpose: The purpose of this work was to clarify the interactions between the parameters used in the {gamma} index with the surface-based distance method, which itself can be viewed as a generalized version of the {gamma} index. The examined parameters included the distance to agreement (DTA)/dose difference (DD) criteria, the percentage used as a passing criterion, and the passing percentage for given DTA/DD criteria. The specific aims of our work were (1) to understand the relationships between the parameters used in the {gamma} index, (2) to determine the detection limit, or the minimum detectable error, of the {gamma} index with a given set of parameters, and (3) to establish a procedure to determine parameters that are consistent with the capacity of an IMRT QA system. Methods: The surface-based distance technique with dose gradient factor was derived, and then the relationship between surface-based distance and {gamma} index was established. The dose gradient factor for plans and measurements of 10 IMRT patients, 10 spine stereotactic radiosurgery (SRS) patients, and 3 Radiological Physics Center (RPC) head and neck phantom were calculated and evaluated. The detection limits of the surface-based distance and {gamma} index methods were examined by introducing known shifts to the 10 IMRT plans. Results: The means of the dose gradient factors were 0.434 mm/% and 0.956 mm/% for the SRS and IMRT plans, respectively. Key quantities (including the mean and 90th and 99th percentiles of the distance distribution) of the surface-based distance distribution between two dose distributions were linearly proportional to the actual shifts. However, the passing percentage of the {gamma} index for a given set of DTA/DD criteria was not associated with the actual shift. For IMRT, using the standard quality assurance criteria of 3 mm/3% DTA/DD and a 90% passing rate, we found that the detection limit of the {gamma} index in terms of global shift was 4.07 mm/4.07 % without noise. Conclusions: Surface-based distance is a direct measure of the difference between two dose distributions and can be used to evaluate or determine parameters for use in calculating the {gamma} index. The dose gradient factor represents the weighting between spatial and dose shift and should be determined before DTA/DD criteria are set. The authors also present a procedure to determine {gamma} index parameters from measurements.

  6. {gamma} parameter and Solar System constraint in chameleon-Brans-Dicke theory

    SciTech Connect (OSTI)

    Saaidi, Kh.; Mohammadi, A.; Sheikhahmadi, H. [Department of Physics, Faculty of Science, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2011-05-15T23:59:59.000Z

    The post Newtonian parameter is considered in the chameleon-Brans-Dicke model. In the first step, the general form of this parameter and also effective gravitational constant is obtained. An arbitrary function for f({Phi}), which indicates the coupling between matter and scalar field, is introduced to investigate validity of solar system constraint. It is shown that the chameleon-Brans-Dicke model can satisfy the solar system constraint and gives us an {omega} parameter of order 10{sup 4}, which is in comparable to the constraint which has been indicated in [19].

  7. Measurement of $J/\\psi\\to\\gamma\\eta_{\\rm c}$ decay rate and $\\eta_{\\rm c}$ parameters at KEDR

    E-Print Network [OSTI]

    Anashin, V V; Baldin, E M; Barladyan, A K; Barnyakov, A Yu; Barnyakov, M Yu; Baru, S E; Basok, I Yu; Bedny, I V; Blinov, A E; Blinov, V E; Bobrov, A V; Bobrovnikov, V S; Bogomyagkov, A V; Bondar, A E; Buzykaev, A R; Eidelman, S I; Glukhovchenko, Yu M; Gulevich, V V; Gusev, D V; Karnaev, S E; Karpov, G V; Karpov, S V; Kharlamova, T A; Kiselev, V A; Kononov, S A; Kotov, K Yu; Kravchenko, E A; Kulikov, V F; Kurkin, G Ya; Kuper, E A; Levichev, E B; Maksimov, D A; Malyshev, V M; Maslennikov, A L; Medvedko, A S; Meshkov, O I; Mishnev, S I; Morozov, I I; Muchnoi, N Yu; Neufeld, V V; Nikitin, S A; Nikolaev, I B; Okunev, I N; Onuchin, A P; Oreshkin, S B; Orlov, I O; Osipov, A A; Peleganchuk, S V; Pivovarov, S G; Piminov, P A; Petrov, V V; Poluektov, A O; Pospelov, G E; Prisekin, V G; Rezanova, O L; Ruban, A A; Sandyrev, V K; Savinov, G A; Shamov, A G; Shatilov, D N; Shwartz, B A; Simonov, E A; Sinyatkin, S V; Skrinsky, A N; Smaluk, V V; Sokolov, A V; Sukharev, A M; Starostina, E V; Talyshev, A A; Tayursky, V A; Telnov, V I; Tikhonov, Yu A; Todyshev, K Yu; Tumaikin, G M; Usov, Yu V; Vorobiov, A I; Yushkov, A N; Zhilich, V N; Zhulanov, V V; Zhuravlev, A N

    2014-01-01T23:59:59.000Z

    Using the inclusive photon spectrum based on a data sample collected at the $J/\\psi$ peak with the KEDR detector at the VEPP-4M $e^+e^-$ collider, we measured the rate of the radiative decay $J/\\psi\\to\\gamma\\eta_{\\rm c}$ as well as $\\eta_{\\rm c}$ mass and width. Taking into account an asymmetric photon lineshape we obtained: $\\Gamma^0_{\\gamma\\eta_{\\rm c}}=2.98\\pm0.18 \\phantom{|}^{+0.15}_{-0.33}$ keV, $M_{\\eta_{\\rm c}} = 2983.5 \\pm 1.4 \\phantom{|}^{+1.6}_{-3.6}$ MeV/$c^2$, $\\Gamma_{\\eta_{\\rm c}} = 27.2 \\pm 3.1 \\phantom{|}^{+5.4}_{-2.6}$ MeV.

  8. Gravimagnetic effect of the barycentric motion of the Sun and determination of the post-Newtonian parameter gamma in the Cassini experiment

    E-Print Network [OSTI]

    S. M. Kopeikin; A. G. Polnarev; G. Schaefer; I. Yu. Vlasov

    2007-03-14T23:59:59.000Z

    The most precise test of the post-Newtonian gamma parameter in the solar system has been achieved in measurement of the frequency shift of radio waves to and from the Cassini spacecraft as they passed near the Sun. The test relies upon the JPL model of radiowave propagation that includes, but does not explicitly parametrize, the impact of the non-stationary component of the gravitational field of the Sun, generated by its barycentric orbital motion, on the Shapiro delay. This non-stationary gravitational field of the Sun is associated with the Lorentz transformation of the metric tensor and the affine connection from the heliocentric to the barycentric frame of the solar system and can be treated as gravimagnetic field. The gravimagnetic field perturbs the propagation of a radio wave and contributes to its frequency shift at the level up to 4 10^{-13} that may affect the precise measurement of the parameter gamma in the Cassini experiment to about one part in 10,000. Our analysis suggests that the translational gravimagnetic field of the Sun can be extracted from the Cassini data, and its effect is separable from the space curvature characterized by the parameter gamma.

  9. Distribution of Correspondence

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1996-08-30T23:59:59.000Z

    Defines correct procedures for distribution of correspondence to the Naval Reactors laboratories. Does not cancel another directive. Expired 8-30-97.

  10. Exclusive \\gamma*\\gamma processes

    E-Print Network [OSTI]

    Chernyak, V L

    2009-01-01T23:59:59.000Z

    A short review of experimental and theoretical results on the large angle cross sections \\gamma\\gamma\\to {two mesons} and the form factors \\gamma*\\gamma\\to P={pi, \\eta, \\eta'} is given.

  11. Correspondence To the editor

    E-Print Network [OSTI]

    California at Berkeley, University of

    Correspondence To the editor: Prenatal origin of childhood acute myeloid leukemias harboring leukemia has been demonstrated for MLL-AF41 in infant leukemia, TEL-AML12,3 in common acute lymphocytic leukemia (cALL), and AML1-ETO4 in acute myeloid leukemia (AML). We investigated whether AML

  12. Correspondence Revisiting recent

    E-Print Network [OSTI]

    Gent, Universiteit

    Correspondence Revisiting recent challenges to the ancient fish-specific genome duplication to the hypothesis that a genome duplication event occurred early during the evolution of ray-finned fishes that appeared to have been duplicated in fish. The fish-specific genome duplication hypothesis was further

  13. Correspondences DDT resistance in

    E-Print Network [OSTI]

    Buckling, Angus

    Magazine R587 Correspondences DDT resistance in flies carries no cost Caroline McCart1, Angus to carry a cost in the absence of pesticide and consequently not to spread to fixation [1,2]. However, DDT resistance in Drosophila melanogaster (DDT-R) is approaching fixation globally, long after withdrawl of DDT

  14. SAPPHiRE: a Small Gamma-Gamma Higgs Factory

    E-Print Network [OSTI]

    S. A. Bogacz; J. Ellis; L. Lusito; D. Schulte; T. Takahashi; M. Velasco; M. Zanetti; F. Zimmermann

    2012-08-14T23:59:59.000Z

    A new particle with mass ~ 125 GeV that resembles the Higgs boson has recently been discovered by ATLAS and CMS. We propose a low-energy gamma-gamma collider as a cost- and time-efficient option for a Higgs factory capable of studying this particle in detail. In the past, this option has been suggested as a possible application of the CLIC two-beam accelerator technology (the CLIC Higgs Experiment, CLICHE) or as an option for the ILC. Here we propose a design based on a pair of \\sim 10 GeV recirculating Linacs (Small Accelerator for Photon-Photon Higgs production using Recirculating Electrons, SAPPHiRE) similar in design to those proposed for the LHeC. We present parameters for the e- beams and sketch a laser backscattering system capable of producing a gamma-gamma peak luminosity of 0.36 \\times 10^34/cm2/s with E_CM (gamma-gamma) \\sim 125 GeV. A gamma-gamma collider with such a luminosity could be used to measure accurately the mass, bbar, WW\\ast, and gamma-gamma decays of the Higgs boson. We also comment on possible synergies with other projects such as LHeC, the ILC or CLIC, and on other physics prospects in gamma-gamma and e-gamma collisions.

  15. Correspondence between Ricci and other dark energies

    E-Print Network [OSTI]

    Surajit Chattopadhyay; Ujjal Debnath

    2010-09-26T23:59:59.000Z

    Purpose of the present paper is to view the correspondence between Ricci and other dark energies. We have considered the Ricci dark energy in presence of dark matter in non-interacting situation. Subsequently, we have derived the pressure and energy density for Ricci dark energy. The equation of state parameter has been generated from these pressure and energy density. Next, we have considered the correspondence between Ricci and other dark energy models, namely tachyonic field, DBI-essence and new agegraphic dark energy without any interaction and investigated possible cosmological consequences.

  16. TESLA*HERA Based gamma-p and gamma-A Colliders

    E-Print Network [OSTI]

    A. K. Ciftci; S. Sultansoy; O. Yavas

    2000-07-05T23:59:59.000Z

    Main parameters and physics search potential of gamma-p and gamma-A colliders, which will be available due to constructing the TESLA linear electron-positron collider tangentially to the HERA proton ring, are discussed.

  17. Reaction Rate Sensitivity of the gamma-Process Path

    E-Print Network [OSTI]

    T. Rauscher

    2004-07-16T23:59:59.000Z

    The location of the (gamma,p)/(gamma,n) and (gamma,alpha)/(gamma,n) line at gamma-process temperatures is discussed, using recently published reaction rates based on global Hauser-Feshbach calculations. The results can directly be compared to previously published, classic gamma-process discussions. The nuclei exhibiting the largest sensitivity to uncertainties in nuclear structure and reaction parameters are specified.

  18. Gamma bursts

    SciTech Connect (OSTI)

    Colgate, S.A.; Petschek, A.G.

    1982-12-09T23:59:59.000Z

    The origin of cosmic gamma bursts is discussed. Radiation thermalization in magnetic fields, spectral mechanisms, and charge separation and photon heating are discussed. (GHT)

  19. Camera Calibration Using Line Correspondences

    E-Print Network [OSTI]

    Hartley, Richard

    Camera Calibration Using Line Correspondences Richard I. Hartley G.E. CRD, Schenectady, NY, 12301. The three cameras may have different unknown calibrations, and the essential matrices corresponding to each, camera calibration and scene reconstruction. In the case where all the three cameras are assumed to have

  20. The neutron-gamma Feynman variance to mean approach: gamma detection and total neutron-gamma detection (theory and practice)

    E-Print Network [OSTI]

    Dina Chernikova; Kĺre Axell; Senada Avdic; Imre Pázsit; Anders Nordlund

    2015-01-23T23:59:59.000Z

    Two versions of the neutron-gamma variance to mean (Feynman-alpha method or Feynman-Y function) formula for either gamma detection only or total neutron-gamma detection, respectively, are derived and compared in this paper. The new formulas have a particular importance for detectors of either gamma photons or detectors sensitive to both neutron and gamma radiation. If applied to a plastic or liquid scintillation detector, the total neutron-gamma detection Feynman-Y expression corresponds to a situation where no discrimination is made between neutrons and gamma particles. The gamma variance to mean formulas are useful when a detector of only gamma radiation is used or when working with a combined neutron-gamma detector at high count rates. The theoretical derivation is based on the Chapman-Kolmogorov equation with inclusion of general reactions and passage intensities for neutrons and gammas, but with the inclusion of prompt reactions only. A one energy group approximation is considered. The comparison of the two different theories is made by using reaction intensities obtained in MCNPX simulations with a simplified geometry for two scintillation detectors and a 252Cf-source enclosed in a steel container. In addition, the variance to mean ratios, neutron, gamma and total neutron-gamma, are evaluated experimentally for a weak 252Cf neutron-gamma source in a steel container, a 137Cs random gamma source and a 22Na correlated gamma source. Due to the focus being on the possibility of using neutron-gamma variance to mean theories for both reactor and safeguards applications, we limited the present study to the general analytical expressions for Feynman-Y formulas.

  1. A Search for the Rare Decay $B\\rightarrow\\gamma\\gamma$

    SciTech Connect (OSTI)

    del Amo Sanchez, P.; Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Tanabe, T.; /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Indian Inst. Tech., Guwahati /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Southern Methodist U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas Nuclear Corp., Austin /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison

    2011-06-02T23:59:59.000Z

    We report the result of a search for the rare decay B{sup 0} {yields} {gamma}{gamma} in 426 fb{sup -1} of data, corresponding to 226 million B{sup 0}{bar B}{sup 0} pairs, collected on the {Upsilon}(4S) resonance at the PEP-II asymmetric-energy e{sup +}e{sup -} collider using the BABAR detector. We use a maximum likelihood fit to extract the signal yield and observe 21{sub -12}{sup +13} signal events with a statistical signficance of 1.9 {sigma}. This corresponds to a branching fraction {Beta}(B{sup 0} {yields} {gamma}{gamma}) = (1.7 {+-} 1.1(stat.) {+-} 0.2(syst.)) x 10{sup -7}. Based on this result, we set a 90% confidence level upper limit of {Beta}(B{sup 0} {yields} {gamma}{gamma}) < 3.2 x 10{sup -7}.

  2. Black Stars and Gamma Ray Bursts

    E-Print Network [OSTI]

    Tanmay Vachaspati

    2007-06-08T23:59:59.000Z

    Stars that are collapsing toward forming a black hole but are frozen near the Schwarzschild horizon are termed ``black stars''. Collisions of black stars, in contrast to black hole collisions, may be sources of gamma ray bursts, whose basic parameters are estimated quite simply and are found to be consistent with observed gamma ray bursts. Black star gamma ray bursts should be preceded by gravitational wave emission similar to that from the coalescence of black holes.

  3. Gamma watermarking

    DOE Patents [OSTI]

    Ishikawa, Muriel Y.; Wood, Lowell L.; Lougheed, Ronald W.; Moody, Kenton J.; Wang, Tzu-Fang

    2004-05-25T23:59:59.000Z

    A covert, gamma-ray "signature" is used as a "watermark" for property identification. This new watermarking technology is based on a unique steganographic or "hidden writing" digital signature, implemented in tiny quantities of gamma-ray-emitting radioisotopic material combinations, generally covertly emplaced on or within an object. This digital signature may be readily recovered at distant future times, by placing a sensitive, high energy-resolution gamma-ray detecting instrument reasonably precisely over the location of the watermark, which location may be known only to the object's owner; however, the signature is concealed from all ordinary detection means because its exceedingly low level of activity is obscured by the natural radiation background (including the gamma radiation naturally emanating from the object itself, from cosmic radiation and material surroundings, from human bodies, etc.). The "watermark" is used in object-tagging for establishing object identity, history or ownership. It thus may serve as an aid to law enforcement officials in identifying stolen property and prosecuting theft thereof. Highly effective, potentially very low cost identification-on demand of items of most all types is thus made possible.

  4. Neutron monitoring systems including gamma thermometers and methods of calibrating nuclear instruments using gamma thermometers

    DOE Patents [OSTI]

    Moen, Stephan Craig; Meyers, Craig Glenn; Petzen, John Alexander; Foard, Adam Muhling

    2012-08-07T23:59:59.000Z

    A method of calibrating a nuclear instrument using a gamma thermometer may include: measuring, in the instrument, local neutron flux; generating, from the instrument, a first signal proportional to the neutron flux; measuring, in the gamma thermometer, local gamma flux; generating, from the gamma thermometer, a second signal proportional to the gamma flux; compensating the second signal; and calibrating a gain of the instrument based on the compensated second signal. Compensating the second signal may include: calculating selected yield fractions for specific groups of delayed gamma sources; calculating time constants for the specific groups; calculating a third signal that corresponds to delayed local gamma flux based on the selected yield fractions and time constants; and calculating the compensated second signal by subtracting the third signal from the second signal. The specific groups may have decay time constants greater than 5.times.10.sup.-1 seconds and less than 5.times.10.sup.5 seconds.

  5. Holographic correspondence in topological superconductors

    E-Print Network [OSTI]

    Palumbo, Giandomenico

    2015-01-01T23:59:59.000Z

    We analytically derive a compatible family of effective field theories that uniquely describe topological superconductors in 3D, their 2D boundary and their 1D defect lines. We start by deriving the topological field theory of a 3D topological superconductor in class DIII, which is consistent with its symmetries. Then we identify the effective theory of a 2D topological superconductor in class D living on the gapped boundary of the 3D system. By employing the holographic correspondence we derive the effective chiral conformal field theory that describes the gapless modes living on the defect lines or effective boundary of the class D topological superconductor. We demonstrate that the chiral central charge is given in terms of the 3D winding number of the bulk which by its turn is equal to the Chern number of its gapped boundary.

  6. Gamma Ray Burst and Soft Gamma Repeaters. Spinning, Precessing Gamma Jets

    E-Print Network [OSTI]

    Daniele Fargion

    1999-06-28T23:59:59.000Z

    Gamma Ray Bursts as recent GRB990123 and GRB990510 are observed to occur in cosmic volumes with a corresponding output reaching, for isotropic explosions, energies as large as two solar masses annihilation. These energies are underestimated because of the neglected role of comparable ejected neutrinos bursts. These extreme power cannot be explained with any standard spherically symmetric Fireball model. A too heavy black hole or Star would be unable to coexist with the shortest millisecond time structure of Gamma ray Burst. Beaming of the gamma radiation may overcome the energy puzzle. However any mild explosive beam $(\\Omega > 10^{-2})$ should not solve the jet containment at those disruptive energies. Only extreme beaming $(\\Omega < 10^{-8})$, by a slow decaying, but long-lived precessing jet, it may coexist with characteristic Supernova energies, apparent GRBs output, statistics as well as their connection with older and nearer SGRs relics.

  7. Thermal neutron capture gamma-rays

    SciTech Connect (OSTI)

    Tuli, J.K.

    1983-01-01T23:59:59.000Z

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

  8. Gamma Ray Bursts

    E-Print Network [OSTI]

    Stahl, Bennett

    2014-01-01T23:59:59.000Z

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

  9. Correspondence Henry E. Sigerist Adolf Meyer

    E-Print Network [OSTI]

    Jäger, Gerhard

    Correspondence Henry E. Sigerist ­ Adolf Meyer 1934­1947 Edited and annotated by Marcel H. Bickel, Switzerland #12;Correspondence Sigerist ­ Meyer Table of Contents 2 Table of Contents 1. Introduction .......................................................................................................................3 1.1. Adolf Meyer (1866

  10. Gamma-ray boxes from axion-mediated dark matter

    SciTech Connect (OSTI)

    Ibarra, Alejandro; Gehler, Sergio López; Pato, Miguel [Physik-Department T30d, Technische Universität München, James-Franck-Strasse, 85748 Garching (Germany); Lee, Hyun Min; Park, Wan-Il, E-mail: ibarra@tum.de, E-mail: hyun.min.lee@cern.ch, E-mail: sergio.lopez@ph.tum.de, E-mail: wipark@kias.re.kr, E-mail: miguel.pato@tum.de [School of Physics, KIAS, Seoul 130-722 (Korea, Republic of)

    2013-05-01T23:59:59.000Z

    We compute the gamma-ray output of axion-mediated dark matter and derive the corresponding constraints set by recent data. In such scenarios the dark matter candidate is a Dirac fermion that pair-annihilates into axions and/or scalars. Provided that the axion decays (at least partly) into photons, these models naturally give rise to a box-shaped gamma-ray spectrum that may present two distinct phenomenological behaviours: a narrow box, resembling a line at half the dark matter mass, or a wide box, spanning an extensive energy range up to the dark matter mass. Remarkably, we find that in both cases a sizable gamma-ray flux is predicted for a thermal relic without fine-tuning the model parameters nor invoking boost factors. This large output is in line with recent Fermi-LAT observations towards the galactic centre region and is on the verge of being excluded. We then make use of the Fermi-LAT and H.E.S.S. data to derive robust, model-independent upper limits on the dark matter annihilation cross section for the narrow and wide box scenarios. H.E.S.S. constraints, in particular, turn out to match the ones from Fermi-LAT at hundreds of GeV and extend to multi-TeV masses. Future ?erenkov telescopes will likely probe gamma-ray boxes from thermal dark matter relics in the whole multi-TeV range, a region hardly accessible to direct detection, collider searches and other indirect detection strategies.

  11. Gamma ray generator

    DOE Patents [OSTI]

    Firestone, Richard B; Reijonen, Jani

    2014-05-27T23:59:59.000Z

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

  12. Quantum hair and the string-black hole correspondence

    E-Print Network [OSTI]

    Gabriele Veneziano

    2013-03-28T23:59:59.000Z

    We consider a thought experiment in which an energetic massless string probes a "stringhole" (a heavy string lying on the correspondence curve between strings and black holes) at large enough impact parameter for the regime to be under theoretical control. The corresponding, explicitly unitary, $S$-matrix turns out to be perturbatively sensitive to the microstate of the stringhole: in particular, at leading order in $l_s/b$, it depends on a projection of the stringhole's Lorentz-contracted quadrupole moment. The string-black hole correspondence is therefore violated if one assumes quantum hair to be exponentially suppressed as a function of black-hole entropy. Implications for the information paradox are briefly discussed.

  13. Gamma ray detector shield

    DOE Patents [OSTI]

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

    1985-08-26T23:59:59.000Z

    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.

  14. Studying Z/gamma*+Jet Production

    SciTech Connect (OSTI)

    Nilsen, Henrik Wold; /Freiburg U.

    2009-07-01T23:59:59.000Z

    The production of jets in association with a Z/{gamma}* boson is an example of an important class of processes at hadron colliders, namely vector boson + jet (V + jet) production. Comparisons of measurements of this class of processes with theory predictions constitute an important, fundamental test of the Standard Model of particle physics, and of the theory of QCD in particular. While having a smaller cross section than other V +jet processes, Z/{gamma}*({yields} e{sup +}e{sup -}) + jets production, with Z/{gamma}* {yields} e{sup +}e{sup -}/{mu}{sup +}{mu}{sup -}, has a distinct experimental signature allowing for measurements characterized by low backgrounds and a direct, precise measurement of the properties of the decay products of the Z/{gamma}* boson. In this thesis, several new measurements of the properties of jets produced in association with a Z/{gamma}* boson in p{bar p} collisions at {radical}s = 1.96 TeV are presented. The cross section for Z/{gamma}*({yields} e{sup +}e{sup -}) + N jet production (N {le} 3) is measured, differential in the transverse momentum of the Nth jet in the event, normalized to the inclusive Z/{gamma}* cross section. Also, the cross section for Z/{gamma}*({yields} e{sup +}e{sup -}) + N jets (N {ge} 1) is measured, differential in the difference in azimuthal angle between the di-electron system and any jet in the event, normalized to unity. The data used in the measurements were collected by the D0 experiment located at the Tevatron Collider of the Fermi National Accelerator Laboratory and correspond to an integrated luminosity of 1.04 fb{sup -1}. The measured jet transverse momentum spectra are compared with the predictions of perturbative calculations at the next-to-leading order in the strong coupling constant. Given the low sensitivity of the calculations to model parameters, these comparisons represent a stringent test of perturbative QCD. One of the main goals currently being pursued in particle physics is the discovery of the only particle predicted by the Standard Model which has so far no been detected experimentally, namely the Higgs boson. It is assumed that the ATLAS and CMS experiments located at the Large Hadron Collider (LHC), a proton-proton collider at {radical}s = 14 TeV, will be able to detect the Higgs boson, or rule out its existence, within the next few years. The collisions delivered by the LHC will also be used to perform a long range of searches for other new particles, for instance particles predicted by models based on the principle of supersymmetry. The associated production of vector bosons with jets has relatively large production rates at the LHC and can produce a long list of different final states which can include charged leptons, missing transverse energy, as well as light- and heavy-flavour jets. This makes V + jet production a major source of background events to many searches for new particles. Most techniques used for estimating the expected number of background events to searches rely on passing the stable final-state particles of simulated hadron collisions generated using a so-called event generator code, through a simulation of the experimental detector system. The development of event generators which are capable of reliably predicting the properties of jets produced in association with a core process, e.g. the production of a vector boson, has been the subject of a large amount of research activity during the last ten years. These efforts have led to the appearance of the CKKW and MLM algorithms which are implemented in several event generators, among them SHERPA and ALPGEN + PYTHIA. The large data sample collected by the D0 experiment during Run II offers an excellent opportunity for validating these new event generators against experimental measurements of V + jet production. As argued above, the Z/{gamma}*({yields} e{sup +}e{sup -}) + jets process offers the combination of a clean experimental signature and large production rates, making it the process of choice for these studies.

  15. Energetics of Gamma Ray Bursts

    E-Print Network [OSTI]

    Raul Jimenez; David Band; Tsvi Piran

    2001-03-16T23:59:59.000Z

    We determine the distribution of total energy emitted by gamma-ray bursts for bursts with fluences and distance information. Our core sample consists of eight bursts with BATSE spectra and spectroscopic redshifts. We extend this sample by adding four bursts with BATSE spectra and host galaxy R magnitudes. From these R magnitudes we calculate a redshift probability distribution; this method requires a model of the host galaxy population. From a sample of ten bursts with both spectroscopic redshifts and host galaxy R magnitudes (some do not have BATSE spectra) we find that the burst rate is proportional to the galaxy luminosity at the epoch of the burst. Assuming that the total energy emitted has a log-normal distribution, we find that the average emitted energy (assumed to be radiated isotropically) is $gamma iso} > = 1.3^{+1.2}_{-1.0} \\times 10^{53}$ ergs (for H$_0$ = 65 km s$^{-1}$ Mpc$^{-1}$, $\\Omega_m=0.3$ and $\\Omega_\\Lambda=0.7$); the distribution has a logarithmic width of $\\sigma_\\gamma=1.7^{+0.7}_{-0.3}$. The corresponding distribution of X-ray afterglow energy (for seven bursts) has $ = 4.0^{+1.6}_{-1.8} \\times 10^{51}$ergs and $\\sigma_X = 1.3^{+0.4}_{-0.3}$. For completeness, we also provide spectral fits for all bursts with BATSE spectra for which there were afterglow searches.

  16. Can gamma-ray bursts constrain quintessence?

    E-Print Network [OSTI]

    T. Di Girolamo; R. Catena; M. Vietri; G. Di Sciascio

    2005-04-27T23:59:59.000Z

    Using the narrow clustering of the geometrically corrected gamma-ray energies released by gamma-ray bursts, we investigate the possibility of using these sources as standard candles to probe cosmological parameters such as the matter density Omega_m and the cosmological constant energy density Omega_Lambda. By simulating different samples of gamma-ray bursts, we find that Omega_m can be determined with accuracy ~7% with data from 300 sources. We also show that, if Omega = 1 is due to a quintessence field, some of the models proposed in the literature may be discriminated from a Universe with cosmological constant, by a similar-sized sample of gamma-ray bursts.

  17. Afterglows as Diagnostics of Gamma Ray Burst Beaming

    E-Print Network [OSTI]

    James E. Rhoads

    1997-12-03T23:59:59.000Z

    If gamma ray bursts are highly collimated, radiating into only a small fraction of the sky, the energy requirements of each event may be reduced by several (up to 4 - 6) orders of magnitude, and the event rate increased correspondingly. The large Lorentz factors (Gamma > 100) inferred from GRB spectra imply relativistic beaming of the gamma rays into an angle 1/Gamma. We are at present ignorant of whether there are ejecta outside this narrow cone. Afterglows allow empirical tests of whether GRBs are well-collimated jets or spherical fireballs. The bulk Lorentz factor decreases and radiation is beamed into an ever increasing solid angle as the burst remnant expands. It follows that if gamma ray bursts are highly collimated, many more optical and radio transients should be observed without associated gamma rays than with them. In addition, a burst whose ejecta are beamed into angle zeta undergoes a qualitative change in evolution when Gamma < 1/zeta: Before this, Gamma ~ r^{-3/2}, while afterwards, Gamma decays exponentially with r. This change results in a potentially observable break in the afterglow light curve. Successful application of either test would eliminate the largest remaining uncertainty in the energy requirements and space density of gamma ray bursters.

  18. System and method for motor parameter estimation

    DOE Patents [OSTI]

    Luhrs, Bin; Yan, Ting

    2014-03-18T23:59:59.000Z

    A system and method for determining unknown values of certain motor parameters includes a motor input device connectable to an electric motor having associated therewith values for known motor parameters and an unknown value of at least one motor parameter. The motor input device includes a processing unit that receives a first input from the electric motor comprising values for the known motor parameters for the electric motor and receive a second input comprising motor data on a plurality of reference motors, including values for motor parameters corresponding to the known motor parameters of the electric motor and values for motor parameters corresponding to the at least one unknown motor parameter value of the electric motor. The processor determines the unknown value of the at least one motor parameter from the first input and the second input and determines a motor management strategy for the electric motor based thereon.

  19. Virtual Compton Scattering off a Spinless Target in the AdS/QCD correspondence

    E-Print Network [OSTI]

    C. Marquet; C. Roiesnel; S. Wallon

    2010-12-15T23:59:59.000Z

    We perform a study of the doubly virtual Compton scattering off a spinless target gamma* P -> gamma* P' within the Anti-de Sitter(AdS)/QCD formalism. We find that the general structure allowed by the Lorentz invariance and gauge invariance of the Compton amplitude is not easily reproduced with the standard recipes of the AdS/QCD correspondence. In the soft-photon regime, where the semi-classical approximation is supposed to apply best, we show that the measurements of the electric and magnetic polarizabilities of a target like the charged pion in real Compton scattering, can already serve as stringent tests, and presumably exclude results based on the AdS/QCD correspondence in its minimal version.

  20. Toda-Schrödinger correspondence and orthogonal polynomials

    E-Print Network [OSTI]

    Satoshi Tsujimoto; Alexei Zhedanov

    2014-04-08T23:59:59.000Z

    It is known that the unrestricted Toda chain is equivalent to the Riccati equation for the Stieltjes function of the orthogonal polynomials. Under a special condition, this Riccati equation can be reduced to the Schr\\"odinger equation. We show that this condition is equivalent to type B solutions of the Toda chain. We establish some nontrivial consequences arising from this Toda-Schr\\"odinger correspondence. In particular, we show that the KdV densities can be identified with the moments of the corresponding orthogonal polynomials. We establish equivalence between type B solutions of the Toda molecule and the Bargmann potentials of the Schr\\"odinger equation.

  1. Geometric Phase and Classical-Quantum Correspondence

    E-Print Network [OSTI]

    Indubala I. Satija; Radha Balakrishnan

    2004-03-05T23:59:59.000Z

    We study the geometric phase factors underlying the classical and the corresponding quantum dynamics of a driven nonlinear oscillator exhibiting chaotic dynamics. For the classical problem, we compute the geometric phase factors associated with the phase space trajectories using Frenet-Serret formulation. For the corresponding quantum problem, the geometric phase associated with the time evolution of the wave function is computed. Our studies suggest that the classical geometric phase may be related to the the difference in the quantum geometric phases between two neighboring eigenstates.

  2. Exact Classical Correspondence in Quantum Cosmology

    E-Print Network [OSTI]

    Moncy V. John

    2014-05-30T23:59:59.000Z

    We find a Friedmann model with appropriate matter/energy density such that the solution of the Wheeler-DeWitt equation exactly corresponds to the classical evolution. The well-known problems in quantum cosmology disappear in the resulting coasting evolution. The exact quantum-classical correspondence is demonstrated with the help of the de Broglie-Bohm and modified de Broglie-Bohm approaches to quantum mechanics. It is reassuring that such a solution leads to a robust model for the universe, which agrees well with cosmological expansion indicated by SNe Ia data.

  3. Technical Standards,DOE Standards and Corresponding Directives...

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

    February 2, 2002 DOE Standards and Corresponding Directives Crosswalk DOE Standards and Corresponding Directives Crosswalk table Technical Standards,DOE Standards and Corresponding...

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

    E-Print Network [OSTI]

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

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

  5. Nuclear Instruments and Methods in Physics Research A 486 (2002) 623638 Simulation of the AGILE gamma-ray imaging detector

    E-Print Network [OSTI]

    2002-01-01T23:59:59.000Z

    gamma-ray imaging detector performance: Part II Veronica Coccoa,d, *, Francesco Longob,d , Marco Tavanic state physics instruments for cosmic gamma-ray detection in space will sub- stantially improve Detector (GRID) is devoted to optimal detection and imaging of cosmic gamma-rays. It is *Corresponding

  6. Going to Ground(s): The War Correspondent’s Memoir

    E-Print Network [OSTI]

    Wilson, Christopher P.

    2015-01-01T23:59:59.000Z

    Obligations in World War II. Washington, DC: SmithsonianNormalcy: Home Fronts, Good Soldiers, War Correspondents. ”War, Literature and the Arts 24 (2012): 1–25. ———. “Stephen

  7. Are gamma-ray bursts the sources of ultra-high energy cosmic rays?

    E-Print Network [OSTI]

    Philipp Baerwald; Mauricio Bustamante; Walter Winter

    2014-07-07T23:59:59.000Z

    We reconsider the possibility that gamma-ray bursts (GRBs) are the sources of the ultra-high energy cosmic rays (UHECRs) within the internal shock model, assuming a pure proton composition of the UHECRs. For the first time, we combine the information from gamma-rays, cosmic rays, prompt neutrinos, and cosmogenic neutrinos quantitatively in a joint cosmic ray production and propagation model, and we show that the information on the cosmic energy budget can be obtained as a consequence. In addition to the neutron model, we consider alternative scenarios for the cosmic ray escape from the GRBs, i.e., that cosmic rays can leak from the sources. We find that the dip model, which describes the ankle in UHECR observations by the pair production dip, is strongly disfavored in combination with the internal shock model because a) unrealistically high baryonic loadings (energy in protons versus energy in electrons/gamma-rays) are needed for the individual GRBs and b) the prompt neutrino flux easily overshoots the corresponding neutrino bound. On the other hand, GRBs may account for the UHECRs in the ankle transition model if cosmic rays leak out from the source at the highest energies. In that case, we demonstrate that future neutrino observations can efficiently test most of the parameter space -- unless the baryonic loading is much larger than previously anticipated.

  8. average neutron parameters: Topics by E-print Network

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

    invariant parameters (ACIPs) are calculated for six groups of BATSE cosmic gamma-ray bursts selected by their peak fluxes on the 1.024 s time scale. The ACIPs represent the...

  9. average parameters required: Topics by E-print Network

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

    invariant parameters (ACIPs) are calculated for six groups of BATSE cosmic gamma-ray bursts selected by their peak fluxes on the 1.024 s time scale. The ACIPs represent the...

  10. Archived EM SSAB Correspondence & Briefings | Department of Energy

    Office of Environmental Management (EM)

    Services Communication & Engagement EM SSAB Archived EM SSAB Correspondence & Briefings Archived EM SSAB Correspondence & Briefings 2006 June 21, 2006 Letter:...

  11. Testing the AdS/CFT Correspondence

    SciTech Connect (OSTI)

    Klebanov, Igor R. [Joseph Henry Laboratories and Princeton Center for Theoretical Science, Princeton University, Princeton, NJ 08544 (United States)

    2008-07-28T23:59:59.000Z

    This lecture begins with some history and basic facts about string theory and its connections with strong interactions. Comparisons of stacks of Dirichlet branes with curved backgrounds produced by them are used to motivate the AdS/CFT correspondence between superconformal gauge theory and string theory on a product of Anti-de Sitter space and a compact manifold. The ensuing duality between semi-classical spinning strings and long gauge theory operators is briefly reviewed. We go on to describe a recent test of the AdS/CFT correspondence using the Wilson loop cusp anomaly as a function of the coupling, which also enters dimensions of high-spin operators. Finally, strongly coupled thermal SYM theory is explored via a black hole in 5-dimensional AdS space, which leads to explicit results for its entropy and shear viscosity.

  12. AdS/Ricci-flat correspondence

    E-Print Network [OSTI]

    Marco M. Caldarelli; Joan Camps; Blaise Goutéraux; Kostas Skenderis

    2014-04-18T23:59:59.000Z

    We present a comprehensive analysis of the AdS/Ricci-flat correspondence, a map between a class of asymptotically locally AdS spacetimes and a class of Ricci-flat spacetimes. We provide a detailed derivation of the map, discuss a number of extensions and apply it to a number of important examples, such as AdS on a torus, AdS black branes and fluids/gravity metrics. In particular, the correspondence links the hydrodynamic regime of asymptotically flat black $p$-branes or the Rindler fluid with that of AdS. It implies that this class of Ricci-flat spacetimes inherits from AdS a generalized conformal symmetry and has a holographic structure. We initiate the discussion of holography by analyzing how the map acts on boundary conditions and holographic 2-point functions.

  13. Influence of composition on microstructural parameters of single crystal nickel-base superalloys

    SciTech Connect (OSTI)

    MacKay, R.A., E-mail: Rebecca.A.MacKay@nasa.gov [NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States); Gabb, T.P. [NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States); Garg, A. [NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States); University of Toledo, 2801 W. Bancroft, Toledo, Ohio 43606 (United States); Rogers, R.B.; Nathal, M.V. [NASA Glenn Research Center, 21000 Brookpark Rd., Cleveland, Ohio 44135 (United States)

    2012-08-15T23:59:59.000Z

    Fourteen nickel-base superalloy single crystals containing a range of chromium (Cr), cobalt (Co), molybdenum (Mo), and rhenium (Re) levels, and fixed amounts of aluminum (Al) and tantalum (Ta), were examined to determine the effect of bulk composition on basic microstructural parameters, including {gamma} Prime solvus, {gamma} Prime volume fraction, topologically close-packed (TCP) phases, {gamma} and {gamma} Prime phase chemistries, and {gamma}-{gamma} Prime lattice mismatch. Regression models describing the influence of bulk alloy composition on each of the microstructural parameters were developed and compared to predictions by a commercially-available software tool that used computational thermodynamics. Co produced the largest change in {gamma} Prime solvus over the wide compositional range explored and Mo produced the biggest effect on the {gamma} lattice parameter over its range, although Re had a very potent influence on all microstructural parameters investigated. Changing the Cr, Co, Mo, and Re contents in the bulk alloy had an impact on their concentrations in the {gamma} matrix and to a smaller extent in the {gamma} Prime phase. The software tool under-predicted {gamma} Prime solvus temperatures and {gamma} Prime volume fractions, and over-predicted TCP phase volume fractions at 982 Degree-Sign C. However, the statistical regression models provided excellent estimations of the microstructural parameters and demonstrated the usefulness of such formulas. - Highlights: Black-Right-Pointing-Pointer Effects of Cr, Co, Mo, and Re on microstructure in new low density superalloys Black-Right-Pointing-Pointer Co produced a large change in {gamma} Prime solvus; Mo had a large effect on lattice mismatch. Black-Right-Pointing-Pointer Re exhibited very potent influence on all microstructural parameters was investigated. Black-Right-Pointing-Pointer {gamma} and {gamma} Prime phase chemistries both varied with temperature and alloy composition. Black-Right-Pointing-Pointer Computational thermodynamic modeling tool did not accurately predict microstructure.

  14. Gamma Ray Bursts in the HAWC Era

    E-Print Network [OSTI]

    Mészáros, Peter; Murase, Kohta; Fox, Derek; Gao, He; Senno, Nicholas

    2015-01-01T23:59:59.000Z

    Gamma-Ray Bursts are the most energetic explosions in the Universe, and are among the most promising for detecting multiple non-electromagnetic signals, including cosmic rays, high energy neutrinos and gravitational waves. The multi-GeV to TeV gamma-ray range of GRB could have significant contributions from hadronic interactions, mixed with more conventional leptonic contributions. This energy range is important for probing the source physics, including overall energetics, the shock parameters and the Lorentz factor. We discuss some of the latest observational and theoretical developments in the field.

  15. Gamma Ray Bursts in the HAWC Era

    E-Print Network [OSTI]

    Peter Mészáros; Katsuaki Asano; Kohta Murase; Derek Fox; He Gao; Nicholas Senno

    2015-06-08T23:59:59.000Z

    Gamma-Ray Bursts are the most energetic explosions in the Universe, and are among the most promising for detecting multiple non-electromagnetic signals, including cosmic rays, high energy neutrinos and gravitational waves. The multi-GeV to TeV gamma-ray range of GRB could have significant contributions from hadronic interactions, mixed with more conventional leptonic contributions. This energy range is important for probing the source physics, including overall energetics, the shock parameters and the Lorentz factor. We discuss some of the latest observational and theoretical developments in the field.

  16. LORENTZ-FACTOR-ISOTROPIC-LUMINOSITY/ENERGY CORRELATIONS OF GAMMA-RAY BURSTS AND THEIR INTERPRETATION

    SciTech Connect (OSTI)

    Lue Jing; Zou Yuanchuan; Lei Weihua; Wu Qingwen; Wang Dingxiong [School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang Bing; Lue Houjun [Department of Physics and Astronomy, University of Nevada Las Vegas, 4505 Maryland Parkway, Box 454002, Las Vegas, NV 89154-4002 (United States); Liang Enwei, E-mail: zouyc@hust.edu.cn, E-mail: leiwh@hust.edu.cn, E-mail: zhang@physics.unlv.edu [Department of Physics, Guangxi University, Nanning 530004 (China)

    2012-05-20T23:59:59.000Z

    The bulk Lorentz factor of the gamma-ray burst (GRB) ejecta ({Gamma}{sub 0}) is a key parameter to understanding GRB physics. Liang et al. have discovered a correlation between {Gamma}{sub 0} and isotropic {gamma}-ray energy: {Gamma}{sub 0}{proportional_to}E{sup 0.25}{sub {gamma},iso,52}. By including more GRBs with updated data and more methods to derive {Gamma}{sub 0}, we confirm this correlation and obtain {Gamma}{sub 0} {approx_equal} 91E{sup 0.29}{sub {gamma},iso,52}. Evaluating the mean isotropic {gamma}-ray luminosities L{sub {gamma},iso} of the GRBs in the same sample, we discover an even tighter correlation {Gamma}{sub 0} {approx_equal} 249L{sup 0.30}{sub {gamma},iso,52}. We propose an interpretation to this later correlation. Invoking a neutrino-cooled hyperaccretion disk around a stellar mass black hole as the central engine of GRBs, we derive jet luminosity powered by neutrino annihilation and baryon loading from a neutrino-driven wind. Applying beaming correction, we finally derive {Gamma}{sub 0}{proportional_to}L{sup 0.22}{sub {gamma},iso}, which is consistent with the data. This suggests that the central engine of long GRBs is likely a stellar mass black hole surrounded by a hyper-accreting disk.

  17. Directional gamma detector

    DOE Patents [OSTI]

    LeVert, Francis E. (Downers Grove, Knoxville, TN); Cox, Samson A. (Downers Grove, IL)

    1981-01-01T23:59:59.000Z

    An improved directional gamma radiation detector has a collector sandwiched etween two layers of insulation of varying thicknesses. The collector and insulation layers are contained within an evacuated casing, or emitter, which releases electrons upon exposure to gamma radiation. Delayed electrons and electrons entering the collector at oblique angles are attenuated as they pass through the insulation layers on route to the collector.

  18. Parameters of charmonium states from KEDR

    E-Print Network [OSTI]

    Aulchenko, V M; Barladyan, A K; Barnyakov, A Yu; Barnyakov, M Yu; Baru, S E; Basok, I Yu; Batrakov, A M; Blinov, A E; Blinov, V E; Bobrov, A V; Bobrovnikov, V S; Bogomyagkov, A V; Bondar, A E; Buzykaev, A R; Eidelman, S I; Grigoriev, D N; Groshev, V R; Glukhovchenko, Yu M; Gulevich, V V; Gusev, D V; Karnaev, S E; Karpov, G V; Karpov, S V; Kharlamova, T A; Kiselev, V A; Kolmogorov, V V; Kononov, S A; Kotov, K Yu; Kravchenko, E A; Kudryavtsev, V N; Kulikov, V F; Kurkin, G Ya; Kuper, E A; Kuyanov, I A; Levichev, E B; Maksimov, D A; Malyshev, V M; Maslennikov, A L; Meshkov, O I; Mishnev, S I; Morozov, I I; Muchnoi, N Yu; Neufeld, V V; Nikitin, S A; Nikolaev, I B; Okunev, I N; Onuchin, A P; Oreshkin, S B; Orlov, I O; Osipov, A A; Ovtin, I V; Peleganchuk, S V; Pivovarov, S G; Piminov, P A; Petrov, V V; Poluektov, A O; Prisekin, V G; Rezanova, O L; Ruban, A A; Sandyrev, V K; Savinov, G A; Shamov, A G; Shatilov, D N; Shwartz, B A; Simonov, E A; Sinyatkin, S V; Skrinsky, A N; Sokolov, A V; Sukharev, A M; Starostina, E V; Talyshev, A A; Tayursky, V A; Telnov, V I; Tikhonov, Yu A; Todyshev, K Yu; Tumaikin, G M; Usov, Yu V; Vorobiov, A I; Zhilich, V N; Zhulanov, V V; Zhuravlev, A N

    2013-01-01T23:59:59.000Z

    We report results of experiments performed with the KEDR detector at the VEPP-4M $e^+e^-$ collider. They include final results for the mass and other parameters of the $J/\\psi$, $\\psi(2S)$ and $\\psi(3770)$ and $J/\\psi\\to\\gamma\\eta_c$ branching fraction determination.

  19. Optical gamma thermometer

    DOE Patents [OSTI]

    Koster, Glen Peter; Xia, Hua; Lee, Boon Kwee

    2013-08-06T23:59:59.000Z

    An optical gamma thermometer includes a metal mass having a temperature proportional to a gamma flux within a core of a nuclear reactor, and an optical fiber cable for measuring the temperature of the heated metal mass. The temperature of the heated mass may be measured by using one or more fiber grating structures and/or by using scattering techniques, such as Raman, Brillouin, and the like. The optical gamma thermometer may be used in conjunction with a conventional reactor heat balance to calibrate the local power range monitors over their useful in-service life. The optical gamma thermometer occupies much less space within the in-core instrument tube and costs much less than the conventional gamma thermometer.

  20. Correspondence Style Guide | Department of Energy

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613PortsmouthBartlesvilleAbout » Contact Us ContactPractices in IndianDebateCorrespondence

  1. Parameter Assignments for Spectral Gamma-Ray Borehole Calibration Models

    Energy Savers [EERE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed offOCHCO2:Introduction toManagementOPAM5Parabolic Trough Parabolic Trough DOE funds solarDkt.

  2. A CSP Field Theory with Helicity Correspondence

    E-Print Network [OSTI]

    Philip Schuster; Natalia Toro

    2014-04-02T23:59:59.000Z

    We propose the first covariant local action describing the propagation of a single free continuous-spin degree of freedom. The theory is simply formulated as a gauge theory in a "vector superspace", but can also be formulated in terms of a tower of symmetric tensor gauge fields. When the spin invariant $\\rho$ vanishes, the helicity correspondence is manifest -- familiar gauge theory actions are recovered and couplings to conserved currents can easily be introduced. For non-zero $\\rho$, a tower of tensor currents must be present, of which only the lowest rank is exactly conserved. A paucity of local gauge-invariant operators for non-zero $\\rho$ suggests that the equations of motion in any interacting theory should be covariant, not invariant, under a generalization of the free theory's gauge symmetry.

  3. Microscopic description of spherical to {gamma}-soft shape transitions in Ba and Xe nuclei

    SciTech Connect (OSTI)

    Li, Z. P. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Physics Department, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Niksic, T.; Vretenar, D. [Physics Department, Faculty of Science, University of Zagreb, 10000 Zagreb (Croatia); Meng, J. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China)

    2010-03-15T23:59:59.000Z

    The rapid transition between spherical and {gamma}-soft shapes in Ba and Xe nuclei in the mass region A>=130 is analyzed using excitation spectra and collective wave functions obtained by diagonalization of a five-dimensional Hamiltonian for quadrupole vibrational and rotational degrees of freedom, with parameters determined by constrained self-consistent relativistic mean-field calculations for triaxial shapes. The results reproduce the characteristic evolution of excitation spectra and E2 transition probabilities, and in general, a good agreement with available data is obtained. The calculated spectra display fingerprints of a second-order shape phase transition that can approximately be described by analytic solutions corresponding to the E(5) dynamical symmetry.

  4. Constraints on Lorentz invariance violation from gamma-ray burst GRB090510

    E-Print Network [OSTI]

    Zhi Xiao; Bo-Qiang Ma

    2010-01-18T23:59:59.000Z

    We obtain modified dispersion relations by requiring the vanishing of determinant of inverse of modified photon propagators in Lorentz invariance violation (LIV) theory. Inspired by these dispersion relations, we give a more general dispersion relation with less assumption and apply it to the recent observed gamma-ray burst GRB090510 to extract various constraints on LIV parameters. We find that the constraint on quantum gravity mass is slightly larger than the Planck mass but is consistent with the other recent observations, so the corresponding LIV coefficient $\\xi_1$ has reached the natural order ($o(1)$) as one expects. From our analysis, the linear LIV corrections to photon group velocity might be not excluded yet.

  5. Soft gamma repeaters Kevin Hurley *

    E-Print Network [OSTI]

    California at Berkeley, University of

    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1331 1. Introduction The soft gamma repeaters (SGRs) are sporadic sources of bursts of X- and gamma-rays), and a rather soft spectrum compared to those of cosmic gamma-ray bursts; a rough description of the spectrumReview Soft gamma repeaters Kevin Hurley * University of California, Berkeley, Space Sciences

  6. Are gamma-ray bursts cosmological?

    E-Print Network [OSTI]

    Horvath, I

    2015-01-01T23:59:59.000Z

    Gamma-ray burst sources are distributed with a high level of isotropy, which is compatible with either a cosmological origin or an extended Galactic halo origin. The brightness distribution is another indicator used to characterize the spatial distribution in distance. In this paper the author discusses detailed fits of the BATSE gamma-ray burst peak-flux distributions with Friedmann models taking into account possible density evolution and standard candle luminosity functions. A chi-square analysis is used to estimate the goodness of the fits and the author derives the significance level of limits on the density evolution and luminosity function parameters. Cosmological models provide a good fit over a range of parameter space which is physically reasonable

  7. Gamma-Ray Bursts

    E-Print Network [OSTI]

    P. Meszaros

    2006-05-30T23:59:59.000Z

    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.

  8. Two-Parameter Dynamics and Geometry

    E-Print Network [OSTI]

    Zhi Hu; Mulin Yan; Sen Hu

    2015-01-10T23:59:59.000Z

    In this paper we present the two-parameter dynamics which is implied by the law of inertia in flat spacetime. A remarkable perception is that (A)dS4 geometry may emerge from the two-parameter dynamics, which exhibits some phenomenon of dynamics/ geometry correspondence. We also discuss the Unruh effects within the context of two-parameter dynamics. In the last section we construct various invariant actions with respect to the broken symmetry groups.

  9. Interactive Correspondence Analysis in a Dynamic Object-Oriented Environment

    E-Print Network [OSTI]

    Jason Bond; George Michailides

    2011-01-01T23:59:59.000Z

    the other moments. h=1 INTERACTIVE CORRESPONDENCE ANALYSISINTERACTIVE CORRESPONDENCE ANALYSIS IN A DYNAMIC OBJECT-A BSTRACT . A highly interactive, user-friendly object-

  10. Observation of eta_c^{prime} Production in gamma gamma Fusion at CLEO

    E-Print Network [OSTI]

    D. M. Asner; CLEO Collaboration

    2005-07-06T23:59:59.000Z

    We report on the observation of the eta_{c}^{prime}(2^{1}S_{0}), the radial excitation of eta_{c}(1^{1}S_{0}) ground state of charmonium, in the two-photon fusion reaction gamma gamma rightarrow eta_{c}^{prime} rightarrow K_{S}^{0}K^{pm}pi^{mp} in 13.6 fb^{-1} of CLEO II/II.V data and 13.1 fb^{-1} of CLEO III data. We obtain M(eta_{c}^{prime})=3642.9 pm 3.1(stat) pm1.5(syst) MeV, and M(eta_{c})=2981.8 pm1.3(stat) pm 1.5(syst) MeV. The corresponding values of hyperfine splittings between ^{1}S_{0} and ^{3}S_{1} states are \\Delta M_{hf}(1S)=115.1 pm 2.0 MeV, Delta M_{hf}(2S)=43.1 pm3.4 MeV. Assuming that the eta_{c} and eta_{c}^{prime} have equal branching fractions to K_{S}K pi, we obtain Gamma_{gamma gamma}(eta_{c}^{prime})=1.3 pm 0.6 keV.

  11. Observation of eta_c^' Production in gamma-gamma Fusion at CLEO

    E-Print Network [OSTI]

    J. Ernst

    2003-06-30T23:59:59.000Z

    We report on the observation of the eta_c^' (2 ^1S_0), the radial excitation of eta_c (1 ^1S_0) ground state of charmonium, in the two-photon fusion reaction gamma gamma to eta_c^' to K_S^0 K^{\\pm} pi^{\\mp} in 13.4 fb^{-1} of CLEO II/II.V data and 9.2 fb^{-1} of CLEO III data. The data have been analyzed to extract the eta_c^' resonance parameters.

  12. Real time gamma-ray signature identifier

    DOE Patents [OSTI]

    Rowland, Mark (Alamo, CA); Gosnell, Tom B. (Moraga, CA); Ham, Cheryl (Livermore, CA); Perkins, Dwight (Livermore, CA); Wong, James (Dublin, CA)

    2012-05-15T23:59:59.000Z

    A real time gamma-ray signature/source identification method and system using principal components analysis (PCA) for transforming and substantially reducing one or more comprehensive spectral libraries of nuclear materials types and configurations into a corresponding concise representation/signature(s) representing and indexing each individual predetermined spectrum in principal component (PC) space, wherein an unknown gamma-ray signature may be compared against the representative signature to find a match or at least characterize the unknown signature from among all the entries in the library with a single regression or simple projection into the PC space, so as to substantially reduce processing time and computing resources and enable real-time characterization and/or identification.

  13. A Measurement of the Inclusive Z / gamma* --> mu+ mu- Cross-Section and Study of W and Z Events in proton - anti-proton Collisions at D0

    SciTech Connect (OSTI)

    Nurse, Emily L

    2005-02-01T23:59:59.000Z

    A measurement of the inclusive Z/{gamma}* {yields} {mu}{sup +}{mu}{sup -} cross section for M{sub {mu}{mu}} > 40 GeV at {radical}s = 1.96 TeV is presented. The measurement is performed using a data sample corresponding to an integrated luminosity of 147.7 pb{sup -1}, collected with the D0 detector at the Tevatron, Fermilab, between September 2002 and October 2003. A total of 14352 di-muon events are selected and a final result of {sigma}(Z/{gamma}*) = 327.8 {+-} 3.4(stat.) {+-} 8.4(syst.) {+-} 21.3(lumi.) pb is obtained. Correcting the number of di-muon events by a factor of 0.885 {+-} 0.015 for the contribution from pure {gamma}* exchange and Z/{gamma}* interference, the inclusive Z {yields} {mu}{sup +}{mu}{sup -} cross section is found to be: {sigma}(Z) = 290.1 {+-} 3.0(stat.) {+-} 7.4(syst.) {+-} 18.9(lumi.) pb. Finally, comparisons of W and Z boson p{sub T} distributions as measured with D0 during Run I of the Tevatron are compared to HERWIG and MC{at}NLO predictions. Relevant parameters in the simulations are tuned to obtain the best possible fit to the data. An excellent agreement is found for both HERWIG and MC{at}NLO.

  14. Robust Limits on Lorentz Violation from Gamma-Ray Bursts

    E-Print Network [OSTI]

    John Ellis; Nick E. Mavromatos; Dimitri V. Nanopoulos; Alexander S. Sakharov; Edward K. G. Sarkisyan

    2005-10-06T23:59:59.000Z

    We constrain the possibility of a non-trivial refractive index in free space corresponding to an energy-dependent velocity of light: c(E) \\simeq c_0 (1 - E/M), where M is a mass scale that might represent effect of quantum-gravitational space-time foam, using the arrival times of sharp features observed in the intensities of radiation with different energies from a large sample of gamma-ray bursters (GRBs) with known redshifts. We use wavelet techniques to identify genuine features, which we confirm in simulations with artificial added noise. Using the weighted averages of the time-lags calculated using correlated features in all the GRB light curves, we find a systematic tendency for more energetic photons to arrive earlier. However, there is a very strong correlation between the parameters characterizing an intrinsic time-lag at the source and a distance-dependent propagation effect. Moreover, the significance of the earlier arrival times is less evident for a subsample of more robust spectral structures. Allowing for intrinsic stochastic time-lags in these features, we establish a statistically robust lower limit: M > 0.9x10^{16} GeV on the scale of violation of Lorentz invariance.

  15. Shape of Lambda hypernuclei in (beta,gamma) deformation plane

    E-Print Network [OSTI]

    Myaing Thi Win; K. Hagino; T. Koike

    2010-12-15T23:59:59.000Z

    We study the shape of $\\Lambda$ hypernuclei in the full ($\\beta,\\gamma$) deformation plane, including both axially symmetric and triaxial quadrupole deformations. To this end, we use the constrained Skyrme Hartree-Fock+BCS method on the three-dimensional Cartesian mesh. The potential energy surface is analyzed for carbon hypernuclei as well as for sd-shell hypernuclei such as $^{27,29}_{\\Lambda}$Si and $^{25,27}_{\\Lambda}$Mg. We show that the potential energy surface in the ($\\beta,\\gamma$) plane is similar to each other between the hypernuclei and the corresponding core nuclei, although the addition of $\\Lambda$ hyperon makes the energy surface somewhat softer along the $\\gamma$ direction. Our calculation implies that the energy of the $\\gamma$ vibration for $^{25,27}_{\\Lambda}$Mg nuclei is lowered by about 0.15 MeV with respect to that of $^{24,26}$Mg nuclei.

  16. Nano {gamma}'/{gamma}'' composite precipitates in Alloy 718

    SciTech Connect (OSTI)

    Phillips, P. J. [Department of Physics, University of Illinois at Chicago, Chicago, Illinois 60607 (United States); McAllister, D.; Gao, Y.; Lv, D.; Williams, R. E. A.; Wang, Y.; Mills, M. J. [Department of Materials Science and Engineering, Ohio State University, Columbus, Ohio 43210 (United States); Peterson, B. [Honeywell Aerospace, Phoenix, Arizona 85034 (United States)

    2012-05-21T23:59:59.000Z

    Nanoscale composite precipitates of Alloy 718 have been investigated with both high-resolution scanning transmission electron microscopy and phase field modeling. Chemical analysis via energy-dispersive x-ray spectroscopy allowed for the differentiation of {gamma}' and {gamma}'' particles, which is not otherwise possible through traditional Z-contrast methods. Phase field modeling was applied to determine the stress distribution and elastic interaction around and between the particles, respectively, and it was determined that a composite particle (of both {gamma}' and {gamma}'') has an elastic energy that is significantly lower than, for example, single {gamma}' and {gamma}'' precipitates which are non-interacting.

  17. An investigation of the electronic wave functions in solids by the Compton scattering of gamma rays

    E-Print Network [OSTI]

    Nha, Sang Kyun

    1968-01-01T23:59:59.000Z

    APPARATUS The instrument, which was successfully used to study the behavior of the broadening of the Compton-scattered radiation, produces monochromatic gamma rays continuously variable in energy by selective Compton scattering of gamma photons emitted... was calculated. The system was adjusted to span the energy of- interest, then a count was taken 137 by using the Cs source. The channel corresponding to the peak 137 of Cs radiation was recorded, thon the pulser setting correspond)+8 to 662 1'eV (gamma ray...

  18. Gamma ray bursts in their historic context

    E-Print Network [OSTI]

    Trimble, V

    2004-01-01T23:59:59.000Z

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

  19. Measurement of the Branching Ratios Gamma(D*+s -> D+s pi0)/Gamma(D*+s ->D+s gamma) and Gamma(D*0 ->D0 pi0)/Gamma(D*0 -> D0gamma)

    SciTech Connect (OSTI)

    Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; /Annecy, LAPP; Grauges, E.; /Barcelona, IFAE; Palano, A.; Pappagallo, M.; Pompili, A.; /Bari U. /INFN, Bari; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; /Beijing, Inst. High Energy Phys.; Eigen, G.; Ofte, I.; Stugu, B. /Bergen U. /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San

    2005-08-23T23:59:59.000Z

    Data samples corresponding to the isospin-violating decay D*{sub s}{sup +} {yields} D{sub s}{sup +}{pi}{sup 0} and the decays D*{sub s}{sup +} {yields} D{sub s}{sup +}, D*{sup 0} {yields} D{sup 0}{pi}{sup 0} and D*{sup 0} {yields} D{sup 0}{gamma} are reconstructed using 90.4 fb{sup -1} of data recorded by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider. The following branching ratios are extracted: {Lambda}(D*{sub s}{sup +} {yields} D{sub s}{sup +}{pi}{sup 0})/{Lambda}(D*{sub s}{sup +} {yields} D{sub s}{sup +}{gamma}) = 0.062 {+-} 0.005(stat.) {+-} 0.006(syst.) and {Lambda}(D*{sup 0} {yields} D{sup 0}{pi}{sup 0})/{Lambda}(D*{sup 0} {yields} D{sup 0}{gamma}) = 1.74 {+-} 0.02(stat.) {+-} 0.13(syst.). Both measurements represent significant improvements over present world averages.

  20. Methods to Collect, Compile, and Analyze Observed Short-lived Fission Product Gamma Data

    SciTech Connect (OSTI)

    Finn, Erin C.; Metz, Lori A.; Payne, Rosara F.; Friese, Judah I.; Greenwood, Lawrence R.; Kephart, Jeremy D.; Pierson, Bruce D.; Ellis, Tere A.

    2011-09-29T23:59:59.000Z

    A unique set of fission product gamma spectra was collected at short times (4 minutes to 1 week) on various fissionable materials. Gamma spectra were collected from the neutron-induced fission of uranium, neptunium, and plutonium isotopes at thermal, epithermal, fission spectrum, and 14-MeV neutron energies. This report describes the experimental methods used to produce and collect the gamma data, defines the experimental parameters for each method, and demonstrates the consistency of the measurements.

  1. Determination of thermal neutron capture gamma yields.

    E-Print Network [OSTI]

    Harper, Thomas Lawrence

    1969-01-01T23:59:59.000Z

    A method of analysing Ge(Li) thermal neutron capture gamma spectra to obtain total gamma yields has been developed. Tie method determines both the yields from the well resolved gamma peaks in a spectrum as well as the gamma ...

  2. Determination of thermal neutron capture gamma yields

    E-Print Network [OSTI]

    Harper, Thomas Lawrence

    1969-01-01T23:59:59.000Z

    A method of analysing Ge(Li) thermal neutron capture gamma spectra to obtain total gamma yields has been developed. Tie method determines both the yields from the well resolved gamma peaks in a spectrum as well as the gamma ...

  3. Gamma Ray Bursts

    E-Print Network [OSTI]

    Peter Mészáros

    2012-04-12T23:59:59.000Z

    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.

  4. Interference effects in the $H(\\rightarrow \\gamma\\gamma) + 2$ jets channel at the LHC

    E-Print Network [OSTI]

    Coradeschi, F; Dixon, L J; Fidanza, N; Hoeche, S; Ita, H; Li, Y; Mazzitelli, J

    2015-01-01T23:59:59.000Z

    We compute the interference between the resonant process $pp\\to H(\\rightarrow \\gamma\\gamma)+2 \\text{ jets}$ and the corresponding continuum background at leading order in QCD. For the Higgs signal, we include gluon fusion (GF) and vector boson fusion (VBF) production channels, while for the background we consider all tree-level contributions, including pure EW effects (${\\cal O}(\\alpha_{QED}^4)$) and QCD contributions (${\\cal O}(\\alpha_{QED}^2 \\alpha_{s}^2)$), plus the loop-induced gluon-initiated process. After convolution with the experimental mass resolution, the main effect of the interference is to shift the position of the mass peak, as in the inclusive GF case studied previously. The apparent mass shift is small in magnitude but strongly dependent on the Higgs width, potentially allowing for a measurement of, or bound on, the width itself. In the $H(\\rightarrow \\gamma\\gamma)+2 \\text{ jets}$ channel, the VBF and GF contributions generate shifts of opposite signs which largely cancel, depending on the se...

  5. Apparatus and method for comparing corresponding acoustic resonances in liquids

    DOE Patents [OSTI]

    Sinha, Dipen N. (Los Almos, NM)

    1999-01-01T23:59:59.000Z

    Apparatus and method for comparing corresponding acoustic resonances in liquids. The present invention permits the measurement of certain characteristics of liquids which affect the speed of sound therein. For example, a direct correlation between the octane rating of gasoline and the speed of sound in a gasoline sample has been experimentally observed. Therefore, changes in the speed of sound therein can be utilized as a sensitive parameter for determining changes in composition of a liquid sample. The present apparatus establishes interference patterns inside of a liquid without requiring the use of very thin, rigorously parallel ceramic discs, but rather uses readily available piezoelectric transducers attached to the outside surface of the usual container for the liquid and located on the same side thereof in the vicinity of one another. That is, various receptacle geometries may be employed, and the driving and receiving transducers may be located on the same side of the receptacle. The cell may also be constructed of any material that is inert to the liquid under investigation. A single-transducer embodiment, where the same transducer provides the excitation to the sample container and receives signals impressed therein, is also described.

  6. Apparatus and method for comparing corresponding acoustic resonances in liquids

    DOE Patents [OSTI]

    Sinha, D.N.

    1999-03-23T23:59:59.000Z

    Apparatus and method are disclosed for comparing corresponding acoustic resonances in liquids. The present invention permits the measurement of certain characteristics of liquids which affect the speed of sound therein. For example, a direct correlation between the octane rating of gasoline and the speed of sound in a gasoline sample has been experimentally observed. Therefore, changes in the speed of sound therein can be utilized as a sensitive parameter for determining changes in composition of a liquid sample. The present apparatus establishes interference patterns inside of a liquid without requiring the use of very thin, rigorously parallel ceramic discs, but rather uses readily available piezoelectric transducers attached to the outside surface of the usual container for the liquid and located on the same side thereof in the vicinity of one another. That is, various receptacle geometries may be employed, and the driving and receiving transducers may be located on the same side of the receptacle. The cell may also be constructed of any material that is inert to the liquid under investigation. A single-transducer embodiment, where the same transducer provides the excitation to the sample container and receives signals impressed therein, is also described. 5 figs.

  7. Observation of J/{psi}{yields}3{gamma}

    SciTech Connect (OSTI)

    Adams, G. S.; Anderson, M.; Cummings, J. P.; Danko, I.; Hu, D.; Moziak, B.; Napolitano, J. [Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); He, Q.; Insler, J.; Muramatsu, H.; Park, C. S.; Thorndike, E. H.; Yang, F. [University of Rochester, Rochester, New York 14627 (United States); Artuso, M.; Blusk, S.; Khalil, S.; Li, J.; Mountain, R.; Nisar, S.; Randrianarivony, K. [Syracuse University, Syracuse, New York 13244 (United States)] (and others)

    2008-09-05T23:59:59.000Z

    We report the first observation of the decay J/{psi}{yields}3{gamma}. The signal has a statistical significance of 6{sigma} and corresponds to a branching fraction of B(J/{psi}{yields}3{gamma})=(1.2{+-}0.3{+-}0.2)x10{sup -5}, in which the errors are statistical and systematic, respectively. The measurement uses {psi}(2S){yields}{pi}{sup +}{pi}{sup -}J/{psi} events acquired with the CLEO-c detector operating at the CESR e{sup +}e{sup -} collider.

  8. Stability of the homogeneous Bose-Einstein condensate at large gas parameter

    E-Print Network [OSTI]

    Abdulla Rakhimov; Chul Koo Kim; Sang-Hoon Kim; Jae Hyung Yee

    2008-01-12T23:59:59.000Z

    The properties of the uniform Bose gas is studied within the optimized variational perturbation theory (Gaussian approximation) in a self-consistent way. It is shown that the atomic BEC with a repulsive interaction becomes unstable when the gas parameter gamma=rho a^3 exceeds a critical value gamma_{crit} ~ 0.01. The quantum corrections beyond the Bogoliubov-Popov approximation to the energy density, chemical potential and pressure in powers of gamma expansions are presented.

  9. LASER-PLASMA-ACCELERATOR-BASED GAMMA GAMMA COLLIDERS

    E-Print Network [OSTI]

    Schroeder, C. B.

    2010-01-01T23:59:59.000Z

    LASER-PLASMA-ACCELERATOR-BASED ?? COLLIDERS ? C. B.linear col- lider based on laser-plasma-accelerators arediscussed, and a laser-plasma-accelerator-based gamma-

  10. Gamma-ray Burst Cosmology

    E-Print Network [OSTI]

    Wang, F Y; Liang, E W

    2015-01-01T23:59:59.000Z

    Gamma-ray bursts (GRBs) are the most luminous electromagnetic explosions in the Universe, which emit up to $8.8\\times10^{54}$ erg isotropic equivalent energy in the hard X-ray band. The high luminosity makes them detectable out to the largest distances yet explored in the Universe. GRBs, as bright beacons in the deep Universe, would be the ideal tool to probe the properties of high-redshift universe: including the cosmic expansion and dark energy, star formation rate, the reionization epoch and the metal enrichment history of the Universe. In this article, we review the luminosity correlations of GRBs, and implications for constraining the cosmological parameters and dark energy. Observations show that the progenitors of long GRBs are massive stars. So it is expected that long GRBs are tracers of star formation rate. We also review the high-redshift star formation rate derived from GRBs, and implications for the cosmic reionization history. The afterglows of GRBs generally have broken power-law spectra, so it...

  11. Real time method and computer system for identifying radioactive materials from HPGe gamma-ray spectroscopy

    DOE Patents [OSTI]

    Rowland, Mark S. (Alamo, CA); Howard, Douglas E. (Livermore, CA); Wong, James L. (Dublin, CA); Jessup, James L. (Tracy, CA); Bianchini, Greg M. (Livermore, CA); Miller, Wayne O. (Livermore, CA)

    2007-10-23T23:59:59.000Z

    A real-time method and computer system for identifying radioactive materials which collects gamma count rates from a HPGe gamma-radiation detector to produce a high-resolution gamma-ray energy spectrum. A library of nuclear material definitions ("library definitions") is provided, with each uniquely associated with a nuclide or isotope material and each comprising at least one logic condition associated with a spectral parameter of a gamma-ray energy spectrum. The method determines whether the spectral parameters of said high-resolution gamma-ray energy spectrum satisfy all the logic conditions of any one of the library definitions, and subsequently uniquely identifies the material type as that nuclide or isotope material associated with the satisfied library definition. The method is iteratively repeated to update the spectrum and identification in real time.

  12. AdS Boundary Conditions and the Topologically Massive Gravity/CFT Correspondence

    SciTech Connect (OSTI)

    Skenderis, Kostas; Taylor, Marika; Rees, Balt C. van [Institute for Theoretical Physics, University of Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam (Netherlands)

    2009-12-15T23:59:59.000Z

    The AdS/CFT correspondence provides a new perspective on recurrent questions in General Relativity such as the allowed boundary conditions at infinity and the definition of gravitational conserved charges. Here we review the main insights obtained in this direction over the last decade and apply the new techniques to Topologically Massive Gravity. We show that this theory is dual to a non-unitary CFT for any value of its parameter mu and becomes a Logarithmic CFT at mu = 1.

  13. The dark connection between the Canis Major dwarf, the Monoceros ring, the gas flaring, the rotation curve and the EGRET excess of diffuse Galactic Gamma Rays

    E-Print Network [OSTI]

    W. de Boer; I. Gebauer; M. Weber; C. Sander; V. Zhukov; D. Kazakov

    2007-10-26T23:59:59.000Z

    The excess of diffuse galactic gamma rays above 1 GeV, as observed by the EGRET telescope on the NASA Compton Gamma Ray Observatory, shows all the key features from Dark Matter (DM) annihilation: (i) the energy spectrum of the excess is the same in all sky directions and is consistent with the gamma rays expected for the annihilation of WIMPs with a mass between 50-100 GeV; (ii) the intensity distribution of the excess in the sky is used to determine the halo profile, which was found to correspond to the usual profile from N-body simulations with additional substructure in the form of two doughnut-shaped structures at radii of 4 and 13 kpc; (iii) recent N-body simulations of the tidal disruption of the Canis Major dwarf galaxy show that it is a perfect progenitor of the ringlike Monoceros tidal stream of stars at 13 kpc with ring parameters in agreement with the EGRET data; (iiii) the mass of the outer ring is so large, that its gravitational effects influence both the gas flaring and the rotation curve of the Milky Way. Both effects are clearly observed in agreement with the DMA interpretation of the EGRET excess.

  14. Constraining axion by polarized prompt emission from gamma ray bursts

    E-Print Network [OSTI]

    A. Rubbia; A. S. Sakharov

    2007-08-21T23:59:59.000Z

    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.

  15. Search for neutrinos from Gamma-Ray Bursts with ANTARES

    E-Print Network [OSTI]

    Eleonora Presani

    2011-04-20T23:59:59.000Z

    A method to search for neutrino induced showers from gamma-ray bursts in the ANTARES detector is presented. ANTARES consists of a three-dimensional array of photosensitive devices that measure Cherenkov light induced by charged particles produced by high energy neutrinos interacting in the detector vicinity. The shower channel is complementary to the more commonly used upgoing muon channel. The corresponding detection volume is smaller, but has the advantage of being sensitive to neutrinos of any flavour.

  16. Simultaneous beta and gamma spectroscopy

    DOE Patents [OSTI]

    Farsoni, Abdollah T. (Corvallis, OR); Hamby, David M. (Corvallis, OR)

    2010-03-23T23:59:59.000Z

    A phoswich radiation detector for simultaneous spectroscopy of beta rays and gamma rays includes three scintillators with different decay time characteristics. Two of the three scintillators are used for beta detection and the third scintillator is used for gamma detection. A pulse induced by an interaction of radiation with the detector is digitally analyzed to classify the type of event as beta, gamma, or unknown. A pulse is classified as a beta event if the pulse originated from just the first scintillator alone or from just the first and the second scintillator. A pulse from just the third scintillator is recorded as gamma event. Other pulses are rejected as unknown events.

  17. VERY HIGH ENERGY GAMMA RAY Tadashi KIFUNE

    E-Print Network [OSTI]

    Enomoto, Ryoji

    particles as progenitor. The particle interaction includes also absorption of gamma rays through the process to detect TeV gamma rays. The current status of gamma ray astronomy in its growing stage is demonstrated of observation 2. Ground-based detection of VHE gamma rays from SN 1006 and Markaraina 501 The review of gamma

  18. Charmonium decays to {gamma}{pi}{sup 0}, {gamma}{eta}, and {gamma}{eta}{sup '}

    SciTech Connect (OSTI)

    Pedlar, T. K.; Xavier, J. [Luther College, Decorah, Iowa 52101 (United States); Cronin-Hennessy, D.; Gao, K. Y.; Hietala, J.; Klein, T.; Poling, R.; Zweber, P. [University of Minnesota, Minneapolis, Minnesota 55455 (United States); Dobbs, S.; Metreveli, Z.; Seth, K. K.; Tan, B. J. Y.; Tomaradze, A. [Northwestern University, Evanston, Illinois 60208 (United States); Libby, J.; Martin, L.; Powell, A.; Thomas, C.; Wilkinson, G. [University of Oxford, Oxford OX1 3RH (United Kingdom); Mendez, H. [University of Puerto Rico, Mayaguez, Puerto Rico 00681 (Puerto Rico); Ge, J. Y. [Purdue University, West Lafayette, Indiana 47907 (United States)] (and others)

    2009-06-01T23:59:59.000Z

    Using data acquired with the CLEO-c detector at the CESR e{sup +}e{sup -} collider, we measure branching fractions for J/{psi}, {psi}(2S), and {psi}(3770) decays to {gamma}{pi}{sup 0}, {gamma}{eta}, and {gamma}{eta}{sup '}. Defining R{sub n}{identical_to}B[{psi}(nS){yields}{gamma}{eta}]/B[{psi}(nS){yields}{gamma}{eta}{sup '}], we obtain R{sub 1}=(21.1{+-}0.9)% and, unexpectedly, an order of magnitude smaller limit, R{sub 2}<1.8% at 90% C.L. We also use J/{psi}{yields}{gamma}{eta}{sup '} events to determine branching fractions of improved precision for the five most copious {eta}{sup '} decay modes.

  19. Testing the millisecond pulsar scenario of the Galactic center gamma-ray excess with very high energy gamma-rays

    E-Print Network [OSTI]

    Qiang Yuan; Kunihito Ioka

    2015-02-09T23:59:59.000Z

    The recent analyses of the Fermi Large Area Telescope data show an extended GeV $\\gamma$-ray excess on top of the expected diffuse background in the Galactic center region, which can be explained with annihilating dark matter or a population of millisecond pulsars (MSPs). We propose to observe the very high energy $\\gamma$-rays for distinguishing the MSP scenario from the dark matter scenario. The GeV $\\gamma$-ray MSPs should release most energy to the relativistic $e^{\\pm}$ wind, which will diffuse in the Galaxy and radiate TeV $\\gamma$-rays through inverse Compton scattering and bremsstrahlung processes. By calculating the spectrum and spatial distribution, we show that such emission is detectable with the next generation very high energy $\\gamma$-ray observatory, the Cherenkov Telescope Array (CTA), under reasonable model parameters. It is essential to search for the multi-wavelength counterparts to the GeV $\\gamma$-ray excess for solving this mystery in the high energy universe.

  20. APS Storage Ring Parameters

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

    Main Parameters APS Storage Ring Parameters M. Borland, G. Decker, L. Emery, W. Guo, K. Harkay, V. Sajaev, C.-Y. Yao Advanced Photon Source September 8, 2010 This document list the...

  1. X Ray Precursors in SGRs: Precessing Gamma Jet Tails

    E-Print Network [OSTI]

    Daniele Fargion

    2001-05-18T23:59:59.000Z

    Weak isolated X-ray precursor events before the main Gamma Ray Burst, GRB, and also rare Soft Gamma Repeaters, SGR, events are in complete disagreement with any Fireball, or Magnetar, one-shoot explosive scenarios. Fireball model in last two years has been deeply modified into a fountain beamed Jet exploding and interacting on external shells to explain GRB fine time structure. On the contrary earlier we proposed a unified scenario for both GRBs-SGRs where a precessing Gamma Jet (of different intensity) and its geometrical beaming is the source of both GRB and SGRs wide morphology. GRBs are peaked SNs Jet spinning and precessing observed along the thin Jet axis. Their mysterious weak X precursors bursts, corresponding to non-negligible energy powers, up to million Supernova ones for GRB, are gamma Jet tails beamed off-axis, observed at X-Ray tails. They are rare, about (3-6)% of all GRBs, but not unique at all. Comparable brief X-ray precursor flashes occurred in rarest and most detailed SGRs events as the 27 and the 29 August 1998 event from SGR 1900+14. The same source has been in very power-full activity on recent 18 April 2001 once again preceded by X-Ray precursors. These events are inconsistent with any Fireball or Magnetar-Mini-Fireball models. We interpret them naturally as earlier marginal blazing of outlying X conical precessing Jet, an off-axis tails surrounding a narrower gamma precessing Jet. Only when the light-house Jet is in on-axis blazing mode toward the Earth we observe the harder power-full SGR event. We predict such a rich X-Ray precursor signals (more numerous then gamma ones) during Soft Gamma Repeater peak activities; they should be abundant and within detection threshold by a permanent monitoring SGRs by Beppo-Sax WFC or Chandra X ray satellites while at peak activity.

  2. Thermonuclear Reaction Rate of 23Mg(p,gamma)24$Al

    E-Print Network [OSTI]

    H. Herndl; M. Fantini; C. Iliades; P. M. Endt; H. Oberhummer

    1998-06-05T23:59:59.000Z

    Updated stellar rates for the reaction 23Mg(p,gamma)24Al are calculated by using all available experimental information on 24Al excitation energies. Proton and gamma-ray partial widths for astrophysically important resonances are derived from shell model calculations. Correspondences of experimentally observed 24Al levels with shell model states are based on application of the isobaric multiplet mass equation. Our new rates suggest that the 23Mg(p,gamma)24Al reaction influences the nucleosynthesis in the mass A>20 region during thermonuclear runaways on massive white dwarfs.

  3. THE PHOTOSPHERIC RADIATION MODEL FOR THE PROMPT EMISSION OF GAMMA-RAY BURSTS: INTERPRETING FOUR OBSERVED CORRELATIONS

    SciTech Connect (OSTI)

    Fan Yizhong; Wei Daming; Zhang Fuwen [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zhang Binbin, E-mail: yzfan@pmo.ac.cn, E-mail: dmwei@pmo.ac.cn, E-mail: fwzhang@pmo.ac.cn, E-mail: bbzhang@psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

    2012-08-10T23:59:59.000Z

    We show that the empirical E{sub p}-L, {Gamma}-L, E{sub p}-{Gamma}, and {eta}-bar{sub {gamma}}-E{sub p} correlations (where L is the time-averaged luminosity of the prompt emission, E{sub p} is the spectral peak energy, {Gamma} is the bulk Lorentz factor, and {eta}-bar{sub {gamma}} is the emission efficiency of gamma-ray bursts, GRBs) are well consistent with the relations between the analogous parameters predicted in the photospheric radiation model of the prompt emission of GRBs. The time-resolved thermal radiation of GRB 090902B does follow the E{sub p}-L and {Gamma}-L correlations. A reliable interpretation of the four correlations in alternative models is still lacking. These may point toward a photospheric origin of prompt emission of some GRBs.

  4. Co-axial, high energy gamma generator

    DOE Patents [OSTI]

    Reijonen, Jani Petteri (Princeton, NJ); Gicquel, Frederic (Pennington, NJ)

    2011-08-16T23:59:59.000Z

    A gamma ray generator includes an ion source in a first chamber. A second chamber is configured co-axially around the first chamber at a lower second pressure. Co-axially arranged plasma apertures separate the two chambers and provide for restricted passage of ions and gas from the first to the second chamber. The second chamber is formed by a puller electrode having at least one long channel aperture to draw ions from the first chamber when the puller electrode is subject to an appropriate applied potential. A plurality of electrodes rings in the third chamber in third pressure co-axially surround the puller electrode and have at least one channel corresponding to the at least one puller electrode aperture and plasma aperture. The electrode rings increase the energy of the ions to a selected energy in stages in passing between successive pairs of the electrodes by application of an accelerating voltage to the successive pairs of accelerator electrodes. A target disposed co-axially around the plurality of electrodes receives the beam of accelerated ions, producing gamma rays.

  5. Gamma Ray Fresnel lenses - why not?

    E-Print Network [OSTI]

    G. K. Skinner

    2006-02-03T23:59:59.000Z

    Fresnel lenses offer the possibility of concentrating the flux of X-rays or gamma-rays flux falling on a geometric area of many square metres onto a focal point which need only be a millimetre or so in diameter (and which may even be very much smaller). They can do so with an efficiency that can approach 100%, and yet they are easily fabricated and have no special alignment requirements. Fresnel lenses can offer diffraction-limited angular resolution, even in a domain where that limit corresponds to less than a micro second of arc. Given all these highly desirable attributes, it is natural to ask why Fresnel gamma ray lenses are not already being used, or at least why there is not yet any mission that plans to use the technology. Possible reasons (apart from the obvious one that nobody thought of doing so) include the narrow bandwidth of simple Fresnel lenses, their very long focal length, and the problems of target finding. It is argued that none of these is a "show stopper" and that this technique should be seriously considered for nuclear astrophysics.

  6. Radiative Transfer Models for Gamma-Ray Bursts

    E-Print Network [OSTI]

    Vurm, Indrek

    2015-01-01T23:59:59.000Z

    We present global radiative transfer models for heated relativistic jets. The simulations include all relevant radiative processes, starting deep in the opaque zone and following the evolution of radiation to and beyond the photosphere of the jet. The transfer models are compared with three gamma-ray bursts GRB 990123, GRB 090902B, and GRB 130427A, which have well-measured and different spectra. The models provide good fits to the observed spectra in all three cases. The fits give estimates for the jet magnetization parameter $\\varepsilon_{\\rm B}$ and the Lorentz factor $\\Gamma$. In the small sample of three bursts, $\\varepsilon_{\\rm B}$ varies between 0.01 and 0.1, and $\\Gamma$ varies between 340 and 1200.

  7. Dual order parameters and the deconfinement transition

    E-Print Network [OSTI]

    Christian S. Fischer; Jens A. Mueller

    2009-10-29T23:59:59.000Z

    We investigate the chiral and the deconfinement transition within the framework of Dyson-Schwinger equations using quenched lattice data for the temperature dependent gluon propagator as input. We extract corresponding order parameters from the Landau gauge quark propagator with U(1)-valued boundary conditions. We study the chiral transition using the conventional quark condensate, whereas for the deconfinement transition we determine the dual condensate ('dressed Polyakov loop'). In addition we consider an alternative order parameter for deconfinement, the dual scalar quark dressing function. As a result we find almost the same transition temperatures for the chiral and deconfinement transitions.

  8. How to Tell a Jet from a Balloon: A Proposed Test for Beaming in Gamma Ray Bursts

    E-Print Network [OSTI]

    James E. Rhoads

    1997-09-15T23:59:59.000Z

    If gamma ray bursts are highly collimated, the energy requirements of each event may be reduced by several (~ 4-6) orders of magnitude, and the event rate increased correspondingly. Extreme conditions in gamma ray bursters lead to highly relativistic motions (bulk Lorentz factors Gamma > 100). This results in strong forward beaming of the emitted radiation in the observer's rest frame. Thus, all information on gamma ray bursts comes from those ejecta emitted in a narrow cone (opening angle 1/Gamma) pointing towards the observer. We are at present ignorant of whether there are ejecta outside that cone or not. The recent detection of longer wavelength transients following gamma ray bursts allows an empirical test of whether gamma ray bursts are collimated jets or spherical fireballs. The bulk Lorentz factor of the burst ejecta will decrease with time after the event, as the ejecta sweep up the surrounding medium. Thus, radiation from the ejecta is beamed into an ever increasing solid angle as the burst remnant evolves. It follows that if gamma ray bursts are highly collimated, many more optical and radio transients should be observed without associated gamma rays than with them. Published supernova searches may contain enough data to test the most extreme models of gamma ray beaming. We close with a brief discussion of other possible consequences of beaming, including its effect on the evolution of burst remnants.

  9. VERY HIGH ENERGY GAMMA RAY Tadashi KIFUNE

    E-Print Network [OSTI]

    Enomoto, Ryoji

    elementary particles as progenitor. The particle interaction includes also absorption of gamma rays through the present time. Detection of the relics of the earlier Universe, such as gamma rays from anti­based tech­ nique to detect TeV gamma rays. The current status of gamma ray astronomy in its growing stage

  10. Gamma ray bursts ROBERT S MACKAY

    E-Print Network [OSTI]

    Rourke, Colin

    Gamma ray bursts ROBERT S MACKAY COLIN ROURKE We propose that a gamma ray burst is a kinematic Gamma ray bursts are intense flashes of electromagnetic radiation of cosmic origin lasting from ten accepted mechanism. We propose that a gamma ray burst is simply a kinematic effect, namely the effect

  11. A PARAMETER STUDY FOR BAROCLINIC VORTEX AMPLIFICATION

    SciTech Connect (OSTI)

    Raettig, Natalie; Klahr, Hubert [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Lyra, Wladimir, E-mail: raettig@mpia.de, E-mail: klahr@mpia.de, E-mail: Wladimir.Lyra@jpl.nasa.gov [Department of Astrophysics, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024 (United States)

    2013-03-10T23:59:59.000Z

    Recent studies have shown that baroclinic vortex amplification is strongly dependent on certain factors, namely, the global entropy gradient, the efficiency of thermal diffusion and/or relaxation as well as numerical resolution. We conduct a comprehensive study of a broad range and combination of various entropy gradients, thermal diffusion and thermal relaxation timescales via local shearing sheet simulations covering the parameter space relevant for protoplanetary disks. We measure the Reynolds stresses as a function of our control parameters and see that there is angular momentum transport even for entropy gradients as low as {beta} = -dln s/dln r = 1/2. Values we expect in protoplanetary disks are between {beta} = 0.5-2.0 The amplification-rate of the perturbations, {Gamma}, appears to be proportional to {beta}{sup 2} and thus proportional to the square of the Brunt-Vaeisaelae frequency ({Gamma}{proportional_to}{beta}{sup 2}{proportional_to}N {sup 2}). The saturation level of Reynolds stresses, on the other hand, seems to be proportional to {beta}{sup 1/2}. This highlights the importance of baroclinic effects even for the low entropy gradients expected in protoplanetary disks.

  12. Gamma-Ray Burst Lines

    E-Print Network [OSTI]

    Michael S. Briggs

    1999-10-20T23:59:59.000Z

    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.

  13. Precision linac and laser technologies for nuclear photonics gamma-ray sources

    SciTech Connect (OSTI)

    Albert, F.; Hartemann, F. V.; Anderson, S. G.; Cross, R. R.; Gibson, D. J.; Hall, J.; Marsh, R. A.; Messerly, M.; Wu, S. S.; Siders, C. W.; Barty, C. P. J. [Lawrence Livermore National Laboratory, NIF and Photon Science, 7000 East Avenue, Livermore, California 94550 (United States)

    2012-05-15T23:59:59.000Z

    Tunable, high precision gamma-ray sources are under development to enable nuclear photonics, an emerging field of research. This paper focuses on the technological and theoretical challenges related to precision Compton scattering gamma-ray sources. In this scheme, incident laser photons are scattered and Doppler upshifted by a high brightness electron beam to generate tunable and highly collimated gamma-ray pulses. The electron and laser beam parameters can be optimized to achieve the spectral brightness and narrow bandwidth required by nuclear photonics applications. A description of the design of the next generation precision gamma-ray source currently under construction at Lawrence Livermore National Laboratory is presented, along with the underlying motivations. Within this context, high-gradient X-band technology, used in conjunction with fiber-based photocathode drive laser and diode pumped solid-state interaction laser technologies, will be shown to offer optimal performance for high gamma-ray spectral flux, narrow bandwidth applications.

  14. Gamma Ray Bursts and CETI

    E-Print Network [OSTI]

    Frank D. Smith Jr

    1993-02-10T23:59:59.000Z

    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.

  15. Gamma radiation field intensity meter

    DOE Patents [OSTI]

    Thacker, L.H.

    1994-08-16T23:59:59.000Z

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

  16. Gamma radiation field intensity meter

    DOE Patents [OSTI]

    Thacker, Louis H. (Knoxville, TN)

    1995-01-01T23:59:59.000Z

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode.

  17. Gamma radiation field intensity meter

    DOE Patents [OSTI]

    Thacker, L.H.

    1995-10-17T23:59:59.000Z

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode. 4 figs.

  18. Gamma radiation field intensity meter

    DOE Patents [OSTI]

    Thacker, Louis H. (Knoxville, TN)

    1994-01-01T23:59:59.000Z

    A gamma radiation intensity meter measures dose rate of a radiation field. The gamma radiation intensity meter includes a tritium battery emitting beta rays generating a current which is essentially constant. Dose rate is correlated to an amount of movement of an electroscope element charged by the tritium battery. Ionizing radiation decreases the voltage at the element and causes movement. A bleed resistor is coupled between the electroscope support element or electrode and the ionization chamber wall electrode.

  19. The Universe Viewed in Gamma-Rays 1 Concept of new gamma ray detector

    E-Print Network [OSTI]

    Enomoto, Ryoji

    a sensitivity of a detector at TeV gamma ray range. This method was used for a non-imaging detector as XrayThe Universe Viewed in Gamma-Rays 1 Concept of new gamma ray detector Satoko Osone Institute Abstract We present a concept of a new gamma ray detector in order to observe undetected TeV gamma ray

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

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    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 fireball central photosphere internal external shocks engine (shocks) (reverse) (forward) gamma-ray UV

  1. Short Gamma-Ray Bursts from Binary Neutron Star Mergers

    E-Print Network [OSTI]

    Roland Oechslin; Thomas Janka

    2006-04-27T23:59:59.000Z

    We present the results from new relativistic hydrodynamic simulations of binary neutron star mergers using realistic non-zero temperature equations of state. We vary several unknown parameters in the system such as the neutron star (NS) masses, their spins and the nuclear equation of state. The results are then investigated with special focus on the post-merger torus-remnant system. Observational implications on the Gamma-ray burst (GRB) energetics are discussed and compared with recent observations.

  2. Hard x-ray or gamma ray laser by a dense electron beam

    SciTech Connect (OSTI)

    Son, S. [18 Caleb Lane, Princeton, New Jersey 08540 (United States); Joon Moon, Sung [8 Benjamin Rush Ln., Princeton, New Jersey 08540 (United States)

    2012-06-15T23:59:59.000Z

    A dense electron beam propagating through a laser undulator can radiate a coherent x-ray or gamma ray. This lasing scheme is studied with the Landau damping theory. The analysis suggests that, with currently available physical parameters, coherent gamma rays of up to 50 keV can be generated. The electron quantum diffraction suppresses the free electron laser action, which limits the maximum radiation.

  3. Property measurement of Higgs boson in the gamma gamma final state with the ATLAS detector at the LHC

    E-Print Network [OSTI]

    Yanping , Huang; The ATLAS collaboration

    2014-01-01T23:59:59.000Z

    With $pp$ collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at center-of-mass energies of 7 TeV and 8 TeV, corresponding to an integrated luminosity of 25 ${\\rm fb}^{-1}$, an improved measurement of the mass of the Higgs boson is derived from a combined fit to the decay channels $H\\rightarrow\\gamma\\gamma$ and $H\\rightarrow ZZ^{*}\\rightarrow 4l$ with improved energy-scale calibrations for photons, electrons and muons as well as other analysis improvements. It is $m_{H}=125.36\\pm0.37{\\rm (stat)}\\pm0.18{\\rm (syst)}$ GeV. Furthermore, measurement of fiducial and differential cross sections are presented in the $H\\rightarrow\\gamma\\gamma$ decay channel using only the 8 TeV data sample with a luminosity of $20.3{\\rm fb}^{-1}$. The observed spectra are statistically limited but broadly in line with the theoretical expectations.

  4. Using a scalar parameter to trace dislocation evolution in atomistic modeling

    SciTech Connect (OSTI)

    Yang, Jinbo [ORNL; Zhang, Z F [Shenyang National Laboratory for Materials Science; Osetskiy, Yury N [ORNL; Stoller, Roger E [ORNL

    2015-01-01T23:59:59.000Z

    A scalar gamma-parameter is proposed from the Nye tensor. Its maximum value occurs along a dislocation line, either straight or curved, when the coordinate system is purposely chosen. This parameter can be easily obtained from the Nye tensor calculated at each atom in atomistic modeling. Using the gamma-parameter, a fully automated approach is developed to determine core atoms and the Burgers vectors of dislocations simultaneously. The approach is validated by revealing the smallest dislocation loop and by tracing the whole formation process of complicated dislocation networks on the fly.

  5. And the remaining 22 photons: The development of gamma ray and gamma ray burst astronomy

    E-Print Network [OSTI]

    Trimble, V

    2005-01-01T23:59:59.000Z

    goblins and cosmic gamma ray bursts. Astrophysics and Spacelinear alignments of gamma-ray burst sources. Journal of theE.E. (eds. ), 1992. Gamma Ray Bursts. Cambridge, Cambridge

  6. Rigidity-dependent cosmic ray energy spectra in the knee region obtained with the GAMMA experiment

    E-Print Network [OSTI]

    A. P. Garyaka; R. M. Martirosov; S. V. Ter-Antonyan; N. Nikolskaya; Y. A. Gallant; L. Jones; J. Procureur

    2007-04-24T23:59:59.000Z

    On the basis of the extensive air shower (EAS) data obtained by the GAMMA experiment, the energy spectra and elemental composition of the primary cosmic rays are derived in the 1-100 PeV energy range. The reconstruction of the primary energy spectra is carried out using an EAS inverse approach in the framework of the SIBYLL2.1 and QGSJET01 interaction models and the hypothesis of power-law primary energy spectra with rigidity-dependent knees. The energy spectra of primary H, He, O-like and Fe-like nuclei obtained with the SIBYLL interaction model agree with corresponding extrapolations of the balloon and satellite data to ~1 PeV energies. The energy spectra obtained from the QGSJET model show a predominantly proton composition in the knee region. The rigidity-dependent knee feature of the primary energy spectra for each interaction model is displayed at the following rigidities: ~2.5+/-0.2 PV (SIBYLL) and ~3.1-4.2 PV (QGSJET). All the results presented are derived taking into account the detector response, the reconstruction uncertainties of the EAS parameters, and fluctuations in the EAS development.

  7. PLoS Medicine | www.plosmedicine.org 1190 Correspondence

    E-Print Network [OSTI]

    PLoS Medicine | www.plosmedicine.org 1190 Correspondence Open access, freely available online [1] raises important points on the poor quality of data for some indicators used to measure progress to review indicators and data on progress toward achieving the MDGs, involving many UN organizations as well

  8. Other U.S. Nuclear Waste Technical Review Board Correspondence

    E-Print Network [OSTI]

    Appendix F Appendix F Other U.S. Nuclear Waste Technical Review Board Correspondence · Letter UNITED STATES NUCLEAR WASTE TECHNICAL REVIEW BOARD 2300 Clarendon Boulevard, Suite 1300 Arlington, VA: Acknowledgement of letter · Letter from Robert R. Loux, Executive Director, Nevada Agency for Nuclear Projects

  9. U.S. Nuclear Waste Technical Review Board Correspondence with

    E-Print Network [OSTI]

    and the DOE's thermal-management strategy could result in excessive handling of spent-fuel assemblies as fuel system. The Board is concerned that assumptions related to receipt of spent fuel from utilitiesAppendix E Appendix E U.S. Nuclear Waste Technical Review Board Correspondence with U

  10. Dimensioning hospital wards using the Erlang loss model Corresponding author

    E-Print Network [OSTI]

    -2006. Finally, we demonstrate the efficiency of merging departments. Keywords: hospital resource allocationDimensioning hospital wards using the Erlang loss model Corresponding author: A.M. de Bruin (MSc of Sciences Department of Mathematics Assistant professor Optimization of Business Processes L. van Zanten

  11. Ideal Observers for Detecting Human Motion: Correspondence Noise.

    E-Print Network [OSTI]

    Yuille, Alan L.

    purpose, models of motion. We perform more psychophysical experiments which are consistent with humansIdeal Observers for Detecting Human Motion: Correspondence Noise. HongJing Lo Department obtain Barlow and Tripathy's classic model as an approximation. Our psychophysical experiments show

  12. Ratchet transport and periodic structures in parameter space

    E-Print Network [OSTI]

    Alan Celestino; Cesar Manchein; Holokx A. Albuquerque; Marcus W. Beims

    2011-11-06T23:59:59.000Z

    Ratchet models are prominent candidates to describe the transport phenomenum in nature in the absence of external bias. This work analyzes the parameter space of a discrete ratchet model and gives direct connections between chaotic domains and a family of isoperiodic stable structures with the ratchet current. The isoperiodic structures appear along preferred direction in the parameter space giving a guide to follow the current, which usually increases inside the structures but is independent of the corresponding period. One of such structures has the shrimp-shaped form which is known to be an universal structure in the parameter space of dissipative systems. Currents in parameter space provide a direct measure of the momentum asymmetry of the multistable and chaotic attractors times the size of the corresponding basin of attraction. Transport structures are shown to exist in the parameter space of the Langevin equation with an external oscillating force.

  13. Dissecting the Gamma-Ray Background in Search of Dark Matter

    SciTech Connect (OSTI)

    Cholis, Ilias; Hooper, Dan; McDermott, Samuel D.

    2014-02-01T23:59:59.000Z

    Several classes of astrophysical sources contribute to the approximately isotropic gamma-ray background measured by the Fermi Gamma-Ray Space Telescope. In this paper, we use Fermi's catalog of gamma-ray sources (along with corresponding source catalogs at infrared and radio wavelengths) to build and constrain a model for the contributions to the extragalactic gamma-ray background from astrophysical sources, including radio galaxies, star-forming galaxies, and blazars. We then combine our model with Fermi's measurement of the gamma-ray background to derive constraints on the dark matter annihilation cross section, including contributions from both extragalactic and galactic halos and subhalos. The resulting constraints are competitive with the strongest current constraints from the Galactic Center and dwarf spheroidal galaxies. As Fermi continues to measure the gamma-ray emission from a greater number of astrophysical sources, it will become possible to more tightly constrain the astrophysical contributions to the extragalactic gamma-ray background. We project that with 10 years of data, Fermi's measurement of this background combined with the improved constraints on the astrophysical source contributions will yield a sensitivity to dark matter annihilations that exceeds the strongest current constraints by a factor of ~ 5 - 10.

  14. Quality assurance for gamma knives

    SciTech Connect (OSTI)

    Jones, E.D.; Banks, W.W.; Fischer, L.E. [Lawrence Livermore National Lab., CA (United States)

    1995-09-01T23:59:59.000Z

    This report describes and summarizes the results of a quality assurance (QA) study of the Gamma Knife, a nuclear medical device used for the gamma irradiation of intracranial lesions. Focus was on the physical aspects of QA and did not address issues that are essentially medical, such as patient selection or prescription of dose. A risk-based QA assessment approach was used. Sample programs for quality control and assurance are included. The use of the Gamma Knife was found to conform to existing standards and guidelines concerning radiation safety and quality control of external beam therapies (shielding, safety reviews, radiation surveys, interlock systems, exposure monitoring, good medical physics practices, etc.) and to be compliant with NRC teletherapy regulations. There are, however, current practices for the Gamma Knife not covered by existing, formalized regulations, standards, or guidelines. These practices have been adopted by Gamma Knife users and continue to be developed with further experience. Some of these have appeared in publications or presentations and are slowly finding their way into recommendations of professional organizations.

  15. AGATA - Advanced Gamma Tracking Array

    E-Print Network [OSTI]

    S. Akkoyun; A. Algora; B. Alikhani; F. Ameil; G. de Angelis; L. Arnold; A. Astier; A. Ataç; Y. Aubert; C. Aufranc; A. Austin; S. Aydin; F. Azaiez; S. Badoer; D. L. Balabanski; D. Barrientos; G. Baulieu; R. Baumann; D. Bazzacco; F. A. Beck; T. Beck; P. Bednarczyk; M. Bellato; M. A. Bentley; G. Benzoni; R. Berthier; L. Berti; R. Beunard; G. Lo Bianco; B. Birkenbach; P. G. Bizzeti; A. M. Bizzeti-Sona; F. Le Blanc; J. M. Blasco; N. Blasi; D. Bloor; C. Boiano; M. Borsato; D. Bortolato; A. J. Boston; H. C. Boston; P. Bourgault; P. Boutachkov; A. Bouty; A. Bracco; S. Brambilla; I. P. Brawn; A. Brondi; S. Broussard; B. Bruyneel; D. Bucurescu; I. Burrows; A. Bürger; S. Cabaret; B. Cahan; E. Calore; F. Camera; A. Capsoni; F. Carrió; G. Casati; M. Castoldi; B. Cederwall; J. -L. Cercus; V. Chambert; M. El Chambit; R. Chapman; L. Charles; J. Chavas; E. Clément; P. Cocconi; S. Coelli; P. J. Coleman-Smith; A. Colombo; S. Colosimo; C. Commeaux; D. Conventi; R. J. Cooper; A. Corsi; A. Cortesi; L. Costa; F. C. L. Crespi; J. R. Cresswell; D. M. Cullen; D. Curien; A. Czermak; D. Delbourg; R. Depalo; T. Descombes; P. Désesquelles; P. Detistov; C. Diarra; F. Didierjean; M. R. Dimmock; Q. T. Doan; C. Domingo-Pardo; M. Doncel; F. Dorangeville; N. Dosme; Y. Drouen; G. Duchęne; B. Dulny; J. Eberth; P. Edelbruck; J. Egea; T. Engert; M. N. Erduran; S. Ertürk; C. Fanin; S. Fantinel; E. Farnea; T. Faul; M. Filliger; F. Filmer; Ch. Finck; G. de France; A. Gadea; W. Gast; A. Geraci; J. Gerl; R. Gernhäuser; A. Giannatiempo; A. Giaz; L. Gibelin; A. Givechev; N. Goel; V. González; A. Gottardo; X. Grave; J. Gr?bosz; R. Griffiths; A. N. Grint; P. Gros; L. Guevara; M. Gulmini; A. Görgen; H. T. M. Ha; T. Habermann; L. J. Harkness; H. Harroch; K. Hauschild; C. He; A. Hernández-Prieto; B. Hervieu; H. Hess; T. Hüyük; E. Ince; R. Isocrate; G. Jaworski; A. Johnson; J. Jolie; P. Jones; B. Jonson; P. Joshi; D. S. Judson; A. Jungclaus; M. Kaci; N. Karkour; M. Karolak; A. Ka?ka?; M. Kebbiri; R. S. Kempley; A. Khaplanov; S. Klupp; M. Kogimtzis; I. Kojouharov; A. Korichi; W. Korten; Th. Kröll; R. Krücken; N. Kurz; B. Y. Ky; M. Labiche; X. Lafay; L. Lavergne; I. H. Lazarus; S. Leboutelier; F. Lefebvre; E. Legay; L. Legeard; F. Lelli; S. M. Lenzi; S. Leoni; A. Lermitage; D. Lersch; J. Leske; S. C. Letts; S. Lhenoret; R. M. Lieder; D. Linget; J. Ljungvall; A. Lopez-Martens; A. Lotodé; S. Lunardi; A. Maj; J. van der Marel; Y. Mariette; N. Marginean; R. Marginean; G. Maron; A. R. Mather; W. M?czy?ski; V. Mendéz; P. Medina; B. Melon; R. Menegazzo; D. Mengoni; E. Merchan; L. Mihailescu; C. Michelagnoli; J. Mierzejewski; L. Milechina; B. Million; K. Mitev; P. Molini; D. Montanari; S. Moon; F. Morbiducci; R. Moro; P. S. Morrall; O. Möller; A. Nannini; D. R. Napoli; L. Nelson; M. Nespolo; V. L. Ngo; M. Nicoletto; R. Nicolini; Y. Le Noa; P. J. Nolan; M. Norman; J. Nyberg; A. Obertelli; A. Olariu; R. Orlandi; D. C. Oxley; C. Özben; M. Ozille; C. Oziol; E. Pachoud; M. Palacz; J. Palin; J. Pancin; C. Parisel; P. Pariset; G. Pascovici; R. Peghin; L. Pellegri; A. Perego; S. Perrier; M. Petcu; P. Petkov; C. Petrache; E. Pierre; N. Pietralla; S. Pietri; M. Pignanelli; I. Piqueras; Z. Podolyak; P. Le Pouhalec; J. Pouthas; D. Pugnére; V. F. E. Pucknell; A. Pullia; B. Quintana; R. Raine; G. Rainovski; L. Ramina; G. Rampazzo; G. La Rana; M. Rebeschini; F. Recchia; N. Redon; M. Reese; P. Reiter; P. H. Regan; S. Riboldi; M. Richer; M. Rigato; S. Rigby; G. Ripamonti; A. P. Robinson; J. Robin; J. Roccaz; J. -A. Ropert; B. Rossé; C. Rossi Alvarez; D. Rosso; B. Rubio; D. Rudolph; F. Saillant; E. ?ahin; F. Salomon; M. -D. Salsac; J. Salt; G. Salvato; J. Sampson; E. Sanchis; C. Santos; H. Schaffner; M. Schlarb; D. P. Scraggs; D. Seddon; M. ?enyi?it; M. -H. Sigward; G. Simpson; J. Simpson; M. Slee; J. F. Smith; P. Sona; B. Sowicki; P. Spolaore; C. Stahl; T. Stanios; E. Stefanova; O. Stézowski; J. Strachan; G. Suliman; P. -A. Söderström; J. L. Tain; S. Tanguy; S. Tashenov; Ch. Theisen; J. Thornhill; F. Tomasi; N. Toniolo; R. Touzery; B. Travers; A. Triossi; M. Tripon; K. M. M. Tun-Lanoë; M. Turcato; C. Unsworth; C. A. Ur; J. J. Valiente-Dobon; V. Vandone; E. Vardaci; R. Venturelli; F. Veronese; Ch. Veyssiere; E. Viscione; R. Wadsworth; P. M. Walker; N. Warr; C. Weber; D. Weisshaar; D. Wells; O. Wieland; A. Wiens; G. Wittwer; H. J. Wollersheim; F. Zocca; N. V. Zamfir; M. Zi?bli?ski; A. Zucchiatti

    2012-09-17T23:59:59.000Z

    The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation gamma-ray spectrometer. AGATA is based on the technique of gamma-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a gamma ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realization of gamma-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly-segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterization of the crystals was measured and compared with detector-response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximize its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer.

  16. On the E{sub 10}/massive type IIA supergravity correspondence

    SciTech Connect (OSTI)

    Henneaux, Marc; Persson, Daniel [Physique Theorique et Mathematique, Universite Libre de Bruxelles and International Solvay Institutes, ULB-Campus Plaine C.P. 231, B-105yes0 Bruxelles (Belgium); Laboratoire de Physique Theorique, Ecole Normale Superieure, 24 rue Lhomond, F-75231 Paris Cedex 05 (France); Jamsin, Ella; Kleinschmidt, Axel [Physique Theorique et Mathematique, Universite Libre de Bruxelles and International Solvay Institutes, ULB-Campus Plaine C.P. 231, B-105yes0 Bruxelles (Belgium)

    2009-02-15T23:59:59.000Z

    In this paper we investigate in detail the correspondence between E{sub 10} and Romans' massive deformation of type IIA supergravity. We analyze the dynamics of a nonlinear sigma model for a spinning particle on the coset space E{sub 10}/K(E{sub 10}) and show that it reproduces the dynamics of the bosonic as well as the fermionic sector of the massive IIA theory, within the standard truncation. The mass deformation parameter corresponds to a generator of E{sub 10} outside the realm of the generators entering the usual D=11 analysis, and is naturally included without any deformation of the coset model for E{sub 10}/K(E{sub 10}). Our analysis thus provides a dynamical unification of the massless and massive versions of type IIA supergravity inside E{sub 10}. We discuss a number of additional and general features of relevance in the analysis of any deformed supergravity in the correspondence to Kac-Moody algebras, including recently studied deformations where the trombone symmetry is gauged.

  17. A Riemann Hilbert correspondence for infinity local systems

    E-Print Network [OSTI]

    Block, Jonathan

    2009-01-01T23:59:59.000Z

    We descibe a dg-equivalence of dg-categories between Block's $\\mathcal{P}_{\\A}$, corresponding to the de Rham dga $\\A$ of a compact manifold M and the dg-category of $\\infty$-local systems on M. We understand this as a generalization of the Riemann-Hilbert correspondence to $\\Z$-graded connections (superconnections in some formulations). An $\\infty$-local system is an $(\\infty,1)$ functor between the $(\\infty,1)$-categories ${\\pi}_{\\infty}M$ and the linear simplicial nerve of the dg-category of cochain complexes. This theory makes crucial use of Igusa's notion of higher holonomy transport for $\\Z$-graded connections which is a derivative of Chen's main idea of generalized holonomy. In the appendix we describe the linear simplicial nerve construction.

  18. Corresponding with the enemy: Eisenhower's letters to the Soviets

    E-Print Network [OSTI]

    Castellanos, Gustavo Edwardo

    1992-01-01T23:59:59.000Z

    Conference, May 25, " in Documents on Disarmament 1960, ed. United States Arms Control and Disarmament Agency (Washington, D. C. : U. S. Government Printing Office, 1961), 88-96. 10. Richard W. Stevenson, The Rise and Fall of Detente: Relaxations... Exploring Options Learning Patience The End of the Correspondence 98 105 111 117 VI CONCLUSION Eisenhower and Khrushchev A Riddle, Shrouded in Mystery, Wrapped in an Enigma REFERENCES APPENDIX 1 APPENDIX 2 VITA 125 125 128 134 148 160...

  19. On Perturbation Components Correspondence between Diffusion and Transport

    SciTech Connect (OSTI)

    G. Palmiotti

    2012-11-01T23:59:59.000Z

    We have established a correspondence between perturbation components in diffusion and transport theory. In particular we have established the correspondence between the leakage perturbation component of the diffusion theory to that of the group self scattering in transport theory. This has been confirmed by practical applications on sodium void reactivity calculations of fast reactors. Why this is important for current investigations? Recently, there has been a renewed interest in designing fast reactors where the sodium void reactivity coefficient is minimized. In particular the ASTRID8,9 reactor concept has been optimized with this goal in mind. The correspondence on the leakage term that has been established here has a twofold implication for the design of this kind of reactors. First, this type of reactor has a radial reflector; therefore, as shown before, the sodium void reactivity coefficient calculation requires the use of transport theory. The minimization of the sodium reactivity coefficient is normally done by increasing the leakage component that has a negative sign. The correspondence established in this paper allows to directly look at this component in transport theory. The second implication is related to the uncertainty evaluation on sodium void reactivity. As it has shown before, the total sodium void reactivity effect is the result of a large compensation (opposite sign) between the scattering (called often spectral) component and the leakage one. Consequently, one has to evaluate separately the uncertainty on each separate component and then combine them statistically. If one wants to compute the cross section sensitivity coefficients of the two different components, the formulation established in this paper allows to achieve this goal by playing on the contribution to the sodium void reactivity coming from the group self scattering of the sodium cross section.

  20. Gamma source for active interrogation

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Lou, Tak Pui; Barletta, William A.

    2012-10-02T23:59:59.000Z

    A cylindrical gamma generator includes a coaxial RF-driven plasma ion source and target. A hydrogen plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical gamma generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which has many openings. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired.

  1. Neutrinos from Gamma Ray Bursts

    E-Print Network [OSTI]

    F. Halzen; G. Jaczko

    1996-02-07T23:59:59.000Z

    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.

  2. Gamma source for active interrogation

    DOE Patents [OSTI]

    Leung, Ka-Ngo (Hercules, CA); Lou, Tak Pui (Berkeley, CA); Barletta, William A. (Oakland, CA)

    2009-09-29T23:59:59.000Z

    A cylindrical gamma generator includes a coaxial RF-driven plasma ion source and target. A hydrogen plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical gamma generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which has many openings. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired.

  3. Measurements of B to V(Gamma) Decays

    SciTech Connect (OSTI)

    Yarritu, Aaron K.; /Stanford U., Phys. Dept.; ,

    2010-09-02T23:59:59.000Z

    The standard model has been highly successful at describing current experimental data. However, extensions of the standard model predict particles that have masses at energy scales that are above the electroweak scale. The flavor-changing neutral current processes of the B meson are sensitive to the influences of these new physics contributions. These processes proceed through loop diagrams, thus allowing new physics to enter at the same order as the standard model. New physics may contribute to the enhancement or suppression of rate asymmetries or the decay rates of these processes. The transition B {yields} V{gamma} (V = K*(892), {rho}(770), {omega}(782), {phi}(1020)) represents radiative decays of the B meson that proceed through penguin processes. Hadronic uncertainties limit the theoretical accuracy of the prediction of the branching fractions. However, uncertainties, both theoretical and experimental, are much reduced when considering quantities involving ratios of branching fractions, such as CP or isospin asymmetries. The most dominant exclusive radiative b {yields} s transition is B {yields} K*{gamma}. We present the best measurements of the branching fractions, direct CP, and isospin asymmetries of B {yields} K*{gamma}. The analogous b {yields} d transitions are B {yields} {rho}{gamma} and B {yields} {omega}{gamma}, which are suppressed by a factor of |V{sub td}/V{sub ts}|{sup 2} {approx} 0.04 relative to B {yields} K*{gamma}. A measurement of the branching fractions and isospin asymmetry of B{sup +} {yields} {rho}{sup +}{gamma} and B{sup 0} {yields} {rho}{sup 0}{gamma}, as well as a search for B {yields} {omega}{gamma}, are also given. These measurements are combined to calculate the ratio of CKM matrix elements |V{sub td}/V{sub ts}|, which corresponds to the length of one side of the unitary triangle. Finally, we present a search for the penguin annihilation process B {yields}{phi}{gamma}. We use a sample of 383 million B{bar B} events collected with the BABAR detector at the PEP-II asymmetric-energy B factory for the analysis of B {yields} K*{gamma}. We measure the branching fractions {Beta}(B{sup 0} {yields} K*{sup 0}{gamma}) = (4.47 {+-} 0.10 {+-} 0.16) x 10{sup -5} and {Beta}(B{sup +} {yields} K*{sup +}{gamma}) = (4.22 {+-} 0.14 {+-} 0.16) x 10{sup -5}. We measure the direct CP asymmetry to be -0.033 < {Alpha}{sub CP} (B {yields} K*{gamma}) < 0.028 and the isospin asymmetry to be 0.017 < {Delta}{sub 0-} < 0.116, where the limits are determined at the 90% C.L. and include both the statistical and systematic uncertainties. Using a sample of 347 million B{bar B} events, we measure the branching fractions {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) = (1.10{sub -0.33}{sup +0.37} {+-} 0.09) x 10{sup -6} and {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) = (0.79{sub -0.20}{sup +0.22} {+-} 0.06) x 10{sup -6}, the isospin asymmetry {Delta} = -0.35 {+-} 0.27, and set a 90% C.L. upper limit {Beta}(B {yields} {omega}{gamma}) < 0.78 x 10{sup -6}. We also measure the isospin-averaged branching fraction {Beta}(B {yields} ({rho}/{omega}){gamma}) = (1.25{sub -0.24}{sup +0.25} {+-} 0.09) x 10{sup -6}, from which we determine |V{sub td}/V{sub ts}|= 0.200{sub -0.020}{sup +0.021} {+-} 0.015, where the first uncertainty is experimental and the second theoretical. Finally, a sample of 124 million B{bar B} events is used to set an upper limit of {Beta}(B {yields} {phi}{gamma}) < 8.5 x 10{sup -7} at the 90% C.L.

  4. Pavement Thickness Design Parameter

    E-Print Network [OSTI]

    Pavement Thickness Design Parameter Impacts 2012 Municipal Streets Seminar November 14, 2012 Paul D. Wiegand, P.E. #12;Pavement Thickness Design · How do cities decide how thick to build their pavements;Pavement Thickness Design · Correct answer ­ A data-based analysis! · Doesn't have to be difficult and time

  5. Higgs boson decays into {\\gamma}{\\gamma} and Z{\\gamma} in the MSSM and BLSSM

    E-Print Network [OSTI]

    Hammad, A; Moretti, S

    2015-01-01T23:59:59.000Z

    We calculate Higgs decay rates into {\\gamma}{\\gamma} and Z{\\gamma} in the Minimal Supersymmetric Standard Model (MSSM) and (B-L) Supersymmetric Standard Model (BLSSM) by allowing for contributions from light staus and charginos. We show that sizable departures are possible from the SM predictions for the 125 GeV state and that they are testable during run 2 at the Large Hadron Collider. Furthermore, we illustrate how a second light scalar Higgs signal in either or both these decay modes can be accessed at the CERN machine rather promptly within the BLSSM, a possibility instead precluded to the MSSM owing to the much larger mass of its heavy scalar state.

  6. PUBLISHED VERSION Gamma ray spectrometer for ITER

    E-Print Network [OSTI]

    Ray Scintillation Spectrometer Rev. Sci. Instrum. 24, 1096 (1953); 10.1063/1.1770609 An Automatic Recording Gamma for the spectrometer is presented. Keywords: tokamak, DT plasma, alpha- particles, diagnostics, gamma- spectrometry

  7. Pulse properties of terrestrial gamma-ray flashes detected by the Fermi Gamma-Ray Burst Monitor

    E-Print Network [OSTI]

    Foley, Suzanne; Briggs, Michael S; Connaughton, Valerie; Tierney, David; McBreen, Sheila; Dwyer, Joseph; Chaplin, Vandiver L; Bhat, P Narayana; Byrne, David; Cramer, Eric; Fishman, Gerald J; Xiong, Shaolin; Greiner, Jochen; Kippen, R Marc; Meegan, Charles A; Paciesas, William S; Preece, Robert D; von Kienlin, Andreas; Wilson-Hodge, Colleen

    2015-01-01T23:59:59.000Z

    The Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-ray Space Telescope has triggered on over 300 terrestrial gamma-ray flashes (TGFs) since its launch in June 2008. With 14 detectors, GBM collects on average ~100 counts per triggered TGF, enabling unprecedented studies of the time profiles of TGFs. Here we present the first rigorous analysis of the temporal properties of a large sample of TGFs (278), including the distributions of the rise and fall times of the individual pulses and their durations. A variety of time profiles are observed with 19 of TGFs having multiple pulses separated in time and 31 clear cases of partially overlapping pulses. The effect of instrumental dead time and pulse pileup on the temporal properties are also presented. As the observed gamma ray pulse structure is representative of the electron flux at the source, TGF pulse parameters are critical to distinguish between relativistic feedback discharge and lightning leader models. We show that at least 67% of TGFs at satellite ...

  8. The Diverse Environments of Gamma-Ray Bursts

    E-Print Network [OSTI]

    Perley, Daniel Alan

    2011-01-01T23:59:59.000Z

    Galaxies of Dark Gamma-Ray Bursts: Observational Constraintsof a Very Bright Gamma- Ray Burst in a Galactic Halo 3.11.3 Gamma-Ray Burst Classi?cation . . . . . . 1.4 Gamma-Ray

  9. Light Curves of Swift Gamma Ray Bursts

    E-Print Network [OSTI]

    Paolo Cea

    2006-09-22T23:59:59.000Z

    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.

  10. Pulsed Gamma-Ray-Burst Afterglows

    E-Print Network [OSTI]

    J. Middleditch

    2009-01-01T23:59:59.000Z

    provides a candidate for the central engine of the gamma-ray burst (GRB) mechanism, both long and short

  11. The Universe Viewed in Gamma-Rays 1 Properties of Gamma-ray Bursts Localized by

    E-Print Network [OSTI]

    Enomoto, Ryoji

    The Universe Viewed in Gamma-Rays 1 Properties of Gamma-ray Bursts Localized by the HETE-2 and localize Gamma-ray bursts (GRBs) in wide field of view. HETE-2 have been localized about 20 GRBs per year hours after the burst. 1. The High Energy Transient Explorer 2 Gamma-ray burst (GRB) is the most

  12. Bulk-edge correspondence for two-dimensional topological insulators

    E-Print Network [OSTI]

    G. M. Graf; M. Porta

    2013-03-19T23:59:59.000Z

    Topological insulators can be characterized alternatively in terms of bulk or edge properties. We prove the equivalence between the two descriptions for two-dimensional solids in the single-particle picture. We give a new formulation of the $\\mathbb{Z}_{2}$-invariant, which allows for a bulk index not relying on a (two-dimensional) Brillouin zone. When available though, that index is shown to agree with known formulations. The method also applies to integer quantum Hall systems. We discuss a further variant of the correspondence, based on scattering theory.

  13. Fresnel-transform's quantum correspondence and quantum optical ABCD Law

    E-Print Network [OSTI]

    Fan Hongyi; Hu Liyun

    2007-05-29T23:59:59.000Z

    Corresponding to Fresnel transform there exists a unitary operator in quantum optics theory, which could be named Fresnel operator (FO). We show that the multiplication rule of FO naturally leads to the quantum optical ABCD law. The canonical operator methods as mapping of ray-transfer ABCD matrix is explicitly shown by FO's normally ordered expansion through the coherent state representation and the technique of integration within an ordered product of operators. We show that time evolution of the damping oscillator embodies the quantum optical ABCD law.

  14. Lyapunov Generation of Entanglement and the Correspondence Principle

    E-Print Network [OSTI]

    C. Petitjean; Ph. Jacquod

    2005-10-20T23:59:59.000Z

    We show how a classically vanishing interaction generates entanglement between two initially nonentangled particles, without affecting their classical dynamics. For chaotic dynamics, the rate of entanglement is shown to saturate at the Lyapunov exponent of the classical dynamics as the interaction strength increases. In the saturation regime, the one-particle Wigner function follows classical dynamics better and better as one goes deeper and deeper in the semiclassical limit. This demonstrates that quantum-classical correspondence at the microscopic level requires neither high temperatures, nor coupling to a large number of external degrees of freedom.

  15. Neutron/gamma coupled library generation and gamma transport calculation with KARMA 1.2

    SciTech Connect (OSTI)

    Hong, S. G. [Dept. of Nuclear Engineering, Kyung Hee Univ., 446-701 Deogyeong-daero, GiHeung-gu, Yongin, Gyeonggi-do (Korea, Republic of); Kim, K. S.; Cho, J. Y.; Lee, K. H. [Korea Atomic Energy Research Inst., 305-353 Duckjin-dong, Yuseong-gu, Daejon (Korea, Republic of)

    2012-07-01T23:59:59.000Z

    KAERI has developed a lattice transport calculation code KARMA and its multi-group cross section library generation system. Recently, the multi-group cross section library generation system has included a gamma cross section generation capability and KARMA also has been improved to include a gamma transport calculation module. This paper addresses the multi-group gamma cross section generation capability for the KARMA 1.2 code and the preliminary test results of the KARMA 1.2 gamma transport calculations. The gamma transport calculation with KARMA 1.2 gives the gamma flux, gamma smeared power, and gamma energy deposition distributions. The results of the KARMA gamma calculations were compared with those of HELIOS and they showed that KARMA 1.2 gives reasonable gamma transport calculation results. (authors)

  16. Parameterizing the Deceleration Parameter

    E-Print Network [OSTI]

    Diego Pavón; Ivan Duran; Sergio del Campo; Ramón Herrera

    2012-12-31T23:59:59.000Z

    We propose and constrain with the latest observational data three parameterizations of the deceleration parameter, valid from the matter era to the far future. They are well behaved and do not diverge at any redshift. On the other hand, they are model independent in the sense that in constructing them the only assumption made was that the Universe is homogeneous and isotropic at large scales.

  17. THE BATSE 5B GAMMA-RAY BURST SPECTRAL CATALOG

    SciTech Connect (OSTI)

    Goldstein, Adam; Preece, Robert D.; Briggs, Michael S.; Burgess, J. Michael [University of Alabama in Huntsville, 320 Sparkman Drive, Huntsville, AL 35899 (United States); Mallozzi, Robert S.; Fishman, Gerald J.; Kouveliotou, Chryssa [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Paciesas, William S. [Universities Space Research Association, 320 Sparkman Drive, Huntsville, AL 35805 (United States)

    2013-10-01T23:59:59.000Z

    We present systematic spectral analyses of gamma-ray bursts (GRBs) detected with the Burst and Transient Source Experiment (BATSE) on board the Compton Gamma-Ray Observatory during its entire nine years of operation. This catalog contains two types of spectra extracted from 2145 GRBs, and fitted with five different spectral models resulting in a compendium of over 19,000 spectra. The models were selected based on their empirical importance to the spectral shape of many GRBs, and the analysis performed was devised to be as thorough and objective as possible. We describe in detail our procedures and criteria for the analyses, and present the bulk results in the form of parameter distributions. This catalog should be considered an official product from the BATSE Science Team, and the data files containing the complete results are available from the High-Energy Astrophysics Science Archive Research Center (HEASARC)

  18. Solar Gamma Rays Powered by Secluded Dark Matter

    E-Print Network [OSTI]

    Brian Batell; Maxim Pospelov; Adam Ritz; Yanwen Shang

    2009-10-08T23:59:59.000Z

    Secluded dark matter models, in which WIMPs annihilate first into metastable mediators, can present novel indirect detection signatures in the form of gamma rays and fluxes of charged particles arriving from directions correlated with the centers of large astrophysical bodies within the solar system, such as the Sun and larger planets. This naturally occurs if the mean free path of the mediator is in excess of the solar (or planetary) radius. We show that existing constraints from water Cerenkov detectors already provide a novel probe of the parameter space of these models, complementary to other sources, with significant scope for future improvement from high angular resolution gamma-ray telescopes such as Fermi-LAT. Fluxes of charged particles produced in mediator decays are also capable of contributing a significant solar system component to the spectrum of energetic electrons and positrons, a possibility which can be tested with the directional and timing information of PAMELA and Fermi.

  19. Relaxed constraints on neutrino oscillation parameters

    E-Print Network [OSTI]

    Daniela P. Kirilova; Mariana P. Panayotova

    2006-08-04T23:59:59.000Z

    We study the cosmological constraints on active-sterile neutrino oscillations nu_e nu_s for the case when nu_s is partially filled initially, i.e. 0 nu_s oscillations, effective after neutrino decoupling, accounting for all known oscillations effects on cosmological nucleosynthesis. Cosmological constraints on oscillation parameters corresponding to higher than 5% He-4 overproduction and different non-zero initial populations of the sterile state delta N_s 0 are relaxed in comparison with the delta N_s = 0 case and the relaxation is proportional to delta N_s.

  20. Extended law of corresponding states for protein solutions

    E-Print Network [OSTI]

    Florian Platten; Néstor E. Valadez-Pérez; Ramón Castańeda-Priego; Stefan U. Egelhaaf

    2015-03-03T23:59:59.000Z

    The so-called extended law of corresponding states, as proposed by Noro and Frenkel [J. Chem. Phys. 113, 2941 (2000)], involves a mapping of the phase behaviors of systems with short-range attractive interactions. While it has already extensively been applied to various model potentials, here we test its applicability to protein solutions with their complex interactions. We successfully map their experimentally determined metastable gas--liquid binodals, as available in the literature, to the binodals of short-range square-well fluids, as determined by previous as well as new Monte Carlo simulations. This is achieved by representing the binodals as a function of the temperature scaled with the critical temperature (or as a function of the reduced second virial coefficient) and the concentration scaled by the cube of an effective particle diameter, where the scalings take into account the attractive and repulsive contributions to the interaction potential, respectively. The scaled binodals of the protein solutions coincide with simulation data of the adhesive hard-sphere fluid. Furthermore, once the repulsive contributions are taken into account by the effective particle diameter, the temperature dependence of the reduced second virial coefficients follows a master curve that corresponds to a linear temperature dependence of the depth of the square-well potential. We moreover demonstrate that, based on this approach and cloud-point measurements only, second virial coefficients can be estimated, which we show to agree with values determined by light scattering or by DLVO-based calculations.

  1. Nonforward Compton scattering in AdS/CFT correspondence

    E-Print Network [OSTI]

    Jian-Hua Gao; Bo-Wen Xiao

    2010-05-20T23:59:59.000Z

    We study the nonforward Compton scattering in particular the deeply virtual Compton scattering from AdS/CFT. We first calculate the contributions from the s-channel and u-channel supergravity diagrams as well as the four point interaction diagram which correspond to the Compton scatterings on a dilaton target in CFT. Furthermore, we study the Compton scattering on a dilatino target. Assuming that protons can be identified as supergravity modes of dilatino, we compare the calculated DVCS cross section to the low-energy experimental data from the H1 and ZEUS collaborations and find good agreement. We also discuss the t-channel graviton exchange contribution and show that it should be dominant in the high-energy limit.

  2. Correspondence between classical dynamics and energy level spacing distribution in the transition billiard systems

    E-Print Network [OSTI]

    Soo-Young Lee; Sunghwan Rim; Eui-Soon Yim; C. H. Lee

    1998-09-05T23:59:59.000Z

    The Robnik billiard is investigated in detail both classically and quantally in the transition range from integrable to almost chaotic system. We find out that a remarkable correspondence between characteristic features of classical dynamics, especially topological structure of integrable regions in the Poincar\\'{e} surface of section, and the statistics of energy level spacings appears with a system parameter $\\lambda$ being varied. It is shown that the variance of the level spacing distribution changes its behavior at every particular values of $\\lambda$ in such a way that classical dynamics changes its topological structure in the Poincar\\'{e} surface of section, while the skewness and the excess of the level spacings seem to be closely relevant to the interface structure between integrable region and chaotic sea rather than inner structure of intergrable regoin.

  3. Thermodynamics of Black Hole Horizons and Kerr/CFT Correspondence

    E-Print Network [OSTI]

    Bin Chen; Shen-xiu Liu; Jia-ju Zhang

    2012-11-02T23:59:59.000Z

    In this paper we investigate the thermodynamics of the inner horizon and its implication on the holographic description of the black hole. We focus on the black holes with two physical horizons. Under reasonable assumption, we prove that the first law of thermodynamics of the outer horizon always indicates that of the inner horizon. As a result, the fact that the area product being mass-independent is equivalent to the relation $T_+S_+=T_-S_-$, with $T_\\pm$ and $S_\\pm$ being the Hawking temperatures and the entropies of the outer and inner horizon respectively. We find that the mass-independence of area product breaks down in general Myers-Perry black holes with spacetime dimension $d\\geq6$ and Kerr-AdS black holes with $d\\geq4$. Moreover we discuss the implication of the first laws of the outer and inner horizons on the thermodynamics of the right- and left-moving sectors of dual CFT in Kerr/CFT correspondence. We show that once the relation $T_+S_+=T_-S_-$ is satisfied, the central charges of two sectors must be same. Furthermore from the thermodynamics relations, we read the dimensionless temperatures of microscopic CFT, which are in exact agreement with the ones obtained from hidden conformal symmetry in the low frequency scattering off the black holes, and then determine the central charges. This method works well in well-known cases in Kerr/CFT correspondence, and reproduce successfully the holographic pictures for 4D Kerr-Newman and 5D Kerr black holes. We go on to predict the central charges and temperatures of a possible holographic CFT description dual to 5D doubly rotating black ring.

  4. Neutron Detector Gamma Insensitivity Criteria

    SciTech Connect (OSTI)

    Kouzes, Richard T.; Ely, James H.; Lintereur, Azaree T.; Stephens, Daniel L.

    2009-10-21T23:59:59.000Z

    The shortage of 3He has triggered the search for an effective alternative neutron detection technology for radiation portal monitor applications. Any new detection technology must satisfy two basic criteria: 1) it must meet the neutron detection efficiency requirement, and 2) it must be insensitive to gamma ray interference at a prescribed level, while still meeting the neutron detection requirement. It is the purpose of this document to define this latter criterion.

  5. CFT/AdS correspondence, massive gravitons, and a connectivity index conjecture

    SciTech Connect (OSTI)

    Aharony, Ofer [Department of Particle Physics, Weizmann Institute of Science, Rehovot 76100 (Israel); Clark, Adam B.; Karch, Andreas [Department of Physics, University of Washington, Seattle, Washington 98195 (United States)

    2006-10-15T23:59:59.000Z

    We discuss the general question of which conformal field theories have dual descriptions in terms of quantum gravity theories on anti-de Sitter space. We analyze in detail the case of a deformed product of n conformal field theories (each of which has a gravity dual), and we claim that the dual description of this is by a quantum gravity theory on a union of n anti-de Sitter spaces, connected at their boundary (by correlations between their boundary conditions). On this union of spaces (n-1) linear combinations of gravitons obtain a mass, and we compute this mass both from the field theory and from the gravity sides of the correspondence, finding the same result in both computations. This is the first example in which a graviton mass in the bulk of anti-de Sitter space arises continuously by varying parameters. The analysis of these deformed product theories leads us to suggest that field theories may be generally classified by a ''connectivity index,'' corresponding to the number of components (connected at the boundary) in the space-time of the dual gravitational background. In the field theory this index roughly counts the number of independent gauge groups, but we do not have a precise general formula for the index.

  6. Gamma Ray Bursts from Minijets

    E-Print Network [OSTI]

    Nir J. Shaviv; Arnon Dar

    1994-07-14T23:59:59.000Z

    Striking similarities exist between high energy gamma ray emission from active galactic nuclei (AGN) and gamma ray bursts (GRBs). They suggest that GRBs are generated by inverse Compton scattering from highly relativistic electrons in transient jets. Such jets may be produced along the axis of an accretion disk formed around stellar black holes (BH) or neutron stars (NS) in BH-NS and NS-NS mergers and in accretion induced collapse of magnetized white dwarfs (WD) or neutron stars in close binary systems. Such events may produce the cosmological GRBs. Transient jets formed by single old magnetized neutron stars in an extended Galactic halo may produce a local population of GRBs. Here we show that jet production of GRBs by inverse Compton scattering can explain quite simply the striking correlations that exist between various temporal features of GRBs, their duration histogram, the power spectrum of their complex multipeak light curves, their power-law high energy spectra and other features of GRBs. Some additional predictions are made including the expected polarization of gamma-rays in the bursts.

  7. Neutrinos from Gamma Ray Bursts

    E-Print Network [OSTI]

    Karl Mannheim

    2000-10-18T23:59:59.000Z

    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.

  8. Damage as Gamma-limit of microfractures in anti-plane linearized elasticity

    E-Print Network [OSTI]

    Lucia Scardia

    2008-03-06T23:59:59.000Z

    A homogenization result is given for a material having brittle inclusions arranged in a periodic structure. According to the relation between the softness parameter and the size of the microstructure, three different limit models are deduced via Gamma-convergence. In particular, damage is obtained as limit of periodically distributed microfractures.

  9. 1 function fe2d_p_fast ( alpha, beta, gamma, delta, a, b, h, T, delt, u0f, v0f ) 2 %*****************************************************************************80

    E-Print Network [OSTI]

    Garvie, Marcus R

    1 function fe2d_p_fast ( alpha, beta, gamma, delta, a, b, h, T, delt, u0f, v0f ) 2 % Parameters not supplied through the argument list will be prompted for. 20 % 21 % The parameters ALPHA, BETA*V/(U+ALPHA) + U*(1-U) 25 % dVdT = delta * nabla V + BETA*U*V/(U+ALPHA) - GAMMA * V 26 % 27 % Licensing: 28 % 29

  10. GeV Emission from Collisional Magnetized Gamma Ray Bursts

    E-Print Network [OSTI]

    P. Mészáros; M. J. Rees

    2011-04-26T23:59:59.000Z

    Magnetic fields may play a dominant role in gamma-ray bursts, and recent observations by the Fermi satellite indicate that GeV radiation, when detected, arrives delayed by seconds from the onset of the MeV component. Motivated by this, we discuss a magnetically dominated jet model where both magnetic dissipation and nuclear collisions are important. We show that, for parameters typical of the observed bursts, such a model involving a realistic jet structure can reproduce the general features of the MeV and a separate GeV radiation component, including the time delay between the two. The model also predicts a multi-GeV neutrino component.

  11. Gamma-ray free-electron lasers: Quantum fluid model

    E-Print Network [OSTI]

    Silva, H M

    2014-01-01T23:59:59.000Z

    A quantum fluid model is used to describe the interacion of a nondegenerate cold relativistic electron beam with an intense optical wiggler taking into account the beam space-charge potential and photon recoil effect. A nonlinear set of coupled equations are obtained and solved numerically. The numerical results shows that in the limit of plasma wave-breaking an ultra-high power radiation pulse are emitted at the$\\gamma$-ray wavelength range which can reach an output intensity near the Schwinger limit depending of the values of the FEL parameters such as detuning and input signal initial phase at the entrance of the interaction region.

  12. Transformation of the extended Gamma function $?^{2,0}_{0,2}[(b,x)]$ with applications to astrophysical thermonuclear functions

    E-Print Network [OSTI]

    M. Aslam Chaudhry

    1998-11-06T23:59:59.000Z

    Two representations of the extended gamma functions $\\Gamma^{2,0}_{0,2}[(b,x)]$ are proved. These representations are exploited to find a transformation relation between two Fox's $H$-functions. These results are used to solve Fox's $H$-function in terms of Meijer's $G$-function for certain values of the parameters. A closed form representation of the kernel of the Bessel type integral transform is also proved.

  13. The energy balancing parameter

    E-Print Network [OSTI]

    Walton R. Gutierrez

    2011-05-10T23:59:59.000Z

    A parameter method is introduced in order to estimate the relationship among the various variables of a system in equilibrium, where the potential energy functions are incompletely known or the quantum mechanical calculations very difficult. No formal proof of the method is given; instead, a sufficient number of valuable examples are shown to make the case for the method's usefulness in classical and quantum systems. The mathematical methods required are quite elementary: basic algebra and minimization of power functions. This method blends advantageously with a simple but powerful approximate method for quantum mechanics, sidestepping entirely formal operators and differential equations. It is applied to the derivation of various well-known results involving centrally symmetric potentials for a quantum particle such as the hydrogen-like atom, the elastic potential and other cases of interest. The same formulas provide estimates for previously unsolved cases. PACS: 03.65.-w 30.00.00

  14. World Bank-MENA Regional-NAMAs and Corresponding Climate Finance...

    Open Energy Info (EERE)

    MENA Regional-NAMAs and Corresponding Climate Finance Instruments Jump to: navigation, search Name World Bank-MENA Regional-NAMAs and Corresponding Climate Finance Instruments...

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

    E-Print Network [OSTI]

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

    2006-02-20T23:59:59.000Z

    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.

  16. Transient Flow in a Heterogeneous Vadose Zone with Uncertain Parameters

    SciTech Connect (OSTI)

    A. M. Tartakovsky; Luis Garcia-Naranjo; Daniel M. Tartakovsky

    2004-02-01T23:59:59.000Z

    We consider transient flow in unsaturated heterogeneous porous media with uncertain hydraulic parameters. Our aim is to provide unbiased predictions (estimates) of system states, such as pressure head, water content, and fluxes, and to quantify the uncertainty associated with such predictions. We achieve this goal by treating hydraulic parameters as random fields and the corresponding flow equations as stochastic. Current stochastic analyses of transient flow in partially saturated soils require linearization of the constitutive relations, which may lead to significant inaccuracies when these relations are highly nonlinear. If relative conductivity and saturation vary exponentially with pressure and the corresponding scaling parameters are random variables, the transient Richards equation is mapped onto a linear equation by means of the Kirchhoff transformation. This allows us to develop deterministic differential equations for the first and second ensemble moments of pressure and saturation. We solve these equations analytically, for vertical infiltration, and compare them with direct Monte Carlo simulations.

  17. Simulated observations of gamma-ray bursts with GLAST

    SciTech Connect (OSTI)

    Bonnell, J. T.; Norris, J. P. [Code 661, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States); Dingus, B. L. [Department of Physics, University of Utah, Salt Lake City, Utah 84112 (United States); Scargle, J. D. [NASA Ames Research Center, MS 245-3, Moffett Field, California 94035 (United States)

    1998-05-16T23:59:59.000Z

    The Gamma-ray Large Area Space Telescope (GLAST) will incorporate high sensitivity, large field of view, and precision tracker technology, providing arc-minute localizations of gamma-ray bursts (GRBs) and exploring GRB physics up to {approx}100 GeV. We have simulated the response of GLAST to GRBs with power-law spectra extending to GeV energies to determine the detailed burst localization capability. The simulated properties of GRBs are based on the BATSE peak flux and duration distributions. GLAST's hodoscopic calorimeter design has sufficiently good angular resolution and discrimination power against cosmic rays that >1 GeV gammas which are only detected in the calorimeter may be utilized for bright sources such as GRBs. Our results indicate that GLAST will detect and image {approx}230 GRBs yr{sup -1} with sensitivity to {approx}100 GeV for {approx}20 bursts yr{sup -1}. Many bright burst localizations will be comparable in size to the current InterPlanetary Network error boxes thus probing the cosmological burst parameter space at nearby redshifts and enabling counterpart searches at all lower energies.

  18. Pulsed pyroelectric crystal-powered gamma source

    SciTech Connect (OSTI)

    Chen, A. X.; Antolak, A. J.; Leung, K.-N.; Raber, T. N.; Morse, D. H. [Sandia National Laboratories, Livermore, CA 94550 (United States)

    2013-04-19T23:59:59.000Z

    A compact pulsed gamma generator is being developed to replace radiological sources used in commercial, industrial and medical applications. Mono-energetic gammas are produced in the 0.4 - 1.0 MeV energy range using nuclear reactions such as {sup 9}Be(d,n{gamma}){sup 10}B. The gamma generator employs an RF-driven inductively coupled plasma ion source to produce deuterium ion current densities up to 2 mA/mm{sup 2} and ampere-level current pulses can be attained by utilizing an array extraction grid. The extracted deuterium ions are accelerated to approximately 300 keV via a compact stacked pyroelectric crystal system and then bombard the beryllium target to generate gammas. The resulting microsecond pulse of gammas is equivalent to a radiological source with curie-level activity.

  19. Evidence for {psi}' Decays into {gamma}{pi}{sup 0} and {gamma}{eta}

    SciTech Connect (OSTI)

    Ablikim, M.; An, Z. H.; Bai, J. Z.; Berger, N.; Bian, J. M.; Cai, X.; Cao, G. F.; Cao, X. X.; Chang, J. F.; Chen, G.; Chen, H. S.; Chen, J. C.; Chen, M. L.; Chen, Y.; Chen, Y. B.; Chu, Y. P.; Dai, H. L.; Dai, J. P.; Deng, Z. Y.; Dong, L. Y. [Institute of High Energy Physics, Beijing 100049 (China)

    2010-12-31T23:59:59.000Z

    The decays {psi}{sup '}{yields}{gamma}{pi}{sup 0}, {gamma}{eta} and {gamma}{eta}{sup '} are studied using data collected with the BESIII detector at the BEPCII e{sup +}e{sup -} collider. The processes {psi}{sup '}{yields}{gamma}{pi}{sup 0} and {psi}{sup '}{yields}{gamma}{eta} are observed for the first time with signal significances of 4.6{sigma} and 4.3{sigma}, respectively. The branching fractions are determined to be B({psi}{sup '}{yields}{gamma}{pi}{sup 0})=(1.58{+-}0.40{+-}0.13)x10{sup -6}, B({psi}{sup '}{yields}{gamma}{eta})=(1.38{+-}0.48{+-}0.09)x10{sup -6}, and B({psi}{sup '}{yields}{gamma}{eta}{sup '})=(126{+-}3{+-}8)x10{sup -6}, where the first errors are statistical and the second ones systematic.

  20. Gamma Ray Burst Central Engines

    E-Print Network [OSTI]

    Todd A. Thompson

    2008-07-04T23:59:59.000Z

    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.

  1. Hard two photon processes \\gamma\\gamma --> M_2 M_1 in QCD

    E-Print Network [OSTI]

    Chernyak, Victor L

    2012-01-01T23:59:59.000Z

    A short review of leading term QCD predictions vs those of the handbag model for large angle cross sections \\gamma\\gamma --> P_2 P_1 (P is the pseudoscalar meson \\pi^{\\pm,o}, K^{\\pm,o}, \\eta), and for \\gamma\\gamma --> V_2 V_1 (V is the neutral vector meson \\rho^o, \\omega, \\phi), in comparison with Belle Collaboration measuments

  2. Effect of in-medium parameters of rho meson in its photoproduction reactions on nuclei

    E-Print Network [OSTI]

    Das, Swapan

    2015-01-01T23:59:59.000Z

    There exist model calculations showing the modification of the hadronic parameters of $\\rho$ meson in the nuclear environment. From these parameters, we extract the $\\rho$ meson nucleus optical potential and show the medium effect due to this potential on the $\\rho$ meson mass distribution spectra in the photonuclear reaction. The calculated results reproduced reasonably the measured $e^+e^-$ invariant mass, i.e., $\\rho$ meson mass, distribution spectra in the $( \\gamma, \\rho^0 \\to e^+e^- )$ reaction on nuclei.

  3. Effect of in-medium parameters of rho meson in its photoproduction reactions on nuclei

    E-Print Network [OSTI]

    Swapan Das

    2015-04-24T23:59:59.000Z

    There exist model calculations showing the modification of the hadronic parameters of $\\rho$ meson in the nuclear environment. From these parameters, we extract the $\\rho$ meson nucleus optical potential and show the medium effect due to this potential on the $\\rho$ meson mass distribution spectra in the photonuclear reaction. The calculated results reproduced reasonably the measured $e^+e^-$ invariant mass, i.e., $\\rho$ meson mass, distribution spectra in the $( \\gamma, \\rho^0 \\to e^+e^- )$ reaction on nuclei.

  4. Gravitational Waves versus X and Gamma Ray Emission in a Short Gamma-Ray Burst

    E-Print Network [OSTI]

    F. G. Oliveira; Jorge A. Rueda; Remo Ruffini

    2014-03-28T23:59:59.000Z

    The recent progress in the understanding the physical nature of neutron star equilibrium configurations and the first observational evidence of a genuinely short gamma-ray burst, GRB 090227B, allows to give an estimate of the gravitational waves versus the X and Gamma-ray emission in a short gamma-ray burst.

  5. LUNAR SOIL SIMULATION TRAFFICABILITY PARAMETERS

    E-Print Network [OSTI]

    Rathbun, Julie A.

    LUNAR SOIL SIMULATION and TRAFFICABILITY PARAMETERS by W. David Carrier, III Lunar Geotechnical.0 RECOMMENDED LUNAR SOIL TRAFFICABILITY PARAMETERS Table 9.14 in the Lunar Sourcebook (Carrier et al. 1991, p. 529) lists the current recommended lunar soil trafficability parameters: bc = 0.017 N/cm2 bN = 35° K

  6. CONSTRAINTS ON VERY HIGH ENERGY GAMMA-RAY EMISSION FROM GAMMA-RAY BURSTS R. Atkins,1,2

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    CONSTRAINTS ON VERY HIGH ENERGY GAMMA-RAY EMISSION FROM GAMMA-RAY BURSTS R. Atkins,1,2 W. Benbow,3 emission from gamma-ray bursts (GRBs) during the prompt emission phase. Detection of >100 GeV counterparts on potential GRB models. Subject headinggs: gamma rays: bursts -- gamma rays: observations 1. INTRODUCTION

  7. GRB 090727 AND GAMMA-RAY BURSTS WITH EARLY-TIME OPTICAL EMISSION

    SciTech Connect (OSTI)

    Kopac, D.; Gomboc, A.; Japelj, J. [Department of Physics, Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana (Slovenia); Kobayashi, S.; Mundell, C. G.; Bersier, D.; Cano, Z.; Smith, R. J.; Steele, I. A.; Virgili, F. J. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead, CH41 1LD (United Kingdom); Guidorzi, C. [Physics Departments, University of Ferrara, via Saragat 1, I-44122, Ferrara (Italy); Melandri, A., E-mail: drejc.kopac@fmf.uni-lj.si [INAF-Osservatorio Astronomico di Brera, via E. Bianchi 46, I-23807 Merate (Italy)

    2013-07-20T23:59:59.000Z

    We present a multi-wavelength analysis of Swift gamma-ray burst GRB 090727, for which optical emission was detected during the prompt gamma-ray emission by the 2 m autonomous robotic Liverpool Telescope and subsequently monitored for a further two days with the Liverpool and Faulkes Telescopes. Within the context of the standard fireball model, we rule out a reverse shock origin for the early-time optical emission in GRB 090727 and instead conclude that the early-time optical flash likely corresponds to emission from an internal dissipation process. Putting GRB 090727 into a broader observational and theoretical context, we build a sample of 36 gamma-ray bursts (GRBs) with contemporaneous early-time optical and gamma-ray detections. From these GRBs, we extract a sub-sample of 18 GRBs, which show optical peaks during prompt gamma-ray emission, and perform detailed temporal and spectral analysis in gamma-ray, X-ray, and optical bands. We find that in most cases early-time optical emission shows sharp and steep behavior, and notice a rich diversity of spectral properties. Using a simple internal shock dissipation model, we show that the emission during prompt GRB phase can occur at very different frequencies via synchrotron radiation. Based on the results obtained from observations and simulation, we conclude that the standard external shock interpretation for early-time optical emission is disfavored in most cases due to sharp peaks ({Delta}t/t < 1) and steep rise/decay indices, and that internal dissipation can explain the properties of GRBs with optical peaks during gamma-ray emission.

  8. Subsurface Geotechnical Parameters Report

    SciTech Connect (OSTI)

    D. Rigby; M. Mrugala; G. Shideler; T. Davidsavor; J. Leem; D. Buesch; Y. Sun; D. Potyondy; M. Christianson

    2003-12-17T23:59:59.000Z

    The Yucca Mountain Project is entering a the license application (LA) stage in its mission to develop the nation's first underground nuclear waste repository. After a number of years of gathering data related to site characterization, including activities ranging from laboratory and site investigations, to numerical modeling of processes associated with conditions to be encountered in the future repository, the Project is realigning its activities towards the License Application preparation. At the current stage, the major efforts are directed at translating the results of scientific investigations into sets of data needed to support the design, and to fulfill the licensing requirements and the repository design activities. This document addresses the program need to address specific technical questions so that an assessment can be made about the suitability and adequacy of data to license and construct a repository at the Yucca Mountain Site. In July 2002, the U.S. Nuclear Regulatory Commission (NRC) published an Integrated Issue Resolution Status Report (NRC 2002). Included in this report were the Repository Design and Thermal-Mechanical Effects (RDTME) Key Technical Issues (KTI). Geotechnical agreements were formulated to resolve a number of KTI subissues, in particular, RDTME KTIs 3.04, 3.05, 3.07, and 3.19 relate to the physical, thermal and mechanical properties of the host rock (NRC 2002, pp. 2.1.1-28, 2.1.7-10 to 2.1.7-21, A-17, A-18, and A-20). The purpose of the Subsurface Geotechnical Parameters Report is to present an accounting of current geotechnical information that will help resolve KTI subissues and some other project needs. The report analyzes and summarizes available qualified geotechnical data. It evaluates the sufficiency and quality of existing data to support engineering design and performance assessment. In addition, the corroborative data obtained from tests performed by a number of research organizations is presented to reinforce conclusions derived from the pool of data gathered within a full QA-controlled domain. An evaluation of the completeness of the current data is provided with respect to the requirements for geotechnical data to support design and performance assessment.

  9. Observations of Gamma-Ray Bursts at Extreme Energies

    E-Print Network [OSTI]

    Aune, Taylor

    2012-01-01T23:59:59.000Z

    of Gamma-Ray Bursts . . . . . . . . . . . . . Redshift-CRUZ OBSERVATIONS OF GAMMA-RAY BURSTS AT EXTREME ENERGIES ADedication xix Acknowledgments xx 1 Gamma-Ray Bursts 1.1

  10. A history of gamma ray bursts and other astronomical conundrums

    E-Print Network [OSTI]

    Trimble, V

    2006-01-01T23:59:59.000Z

    V. Trimble, in “Gamma Ray Bursts: 30 Years of Discovery,”V. Trimble, in “Gamma Ray Bursts,” Ed. C. Ho et al. ,A History of Gamma Ray Bursts and Other Astronomical

  11. Klein-Nishina effects on the high-energy gamma-ray emission of gamma-ray bursts

    SciTech Connect (OSTI)

    Wang Xiangyu [Department of Astronomy, Nanjing University, Nanjing 210093 (China) and Key Laboratory of Modern Astronomy and Astrophysics (Nanjing University), Ministry of Education, Nanjing 210093 (China)

    2010-10-15T23:59:59.000Z

    Prompt and long-lived high-energy (>100 MeV) gamma-ray emission has been detected by Fermi Large Area Telescope (LAT) recently from more than ten gamma-ray bursts. It has been suggested that such emission is produced by synchrotron radiation of electrons accelerated in internal and external shocks. Here we show that, during both the prompt and early afterglow phase, inverse-Compton (IC) scattering of these electrons with synchrotron photons are typically in the Klein-Nishina (KN) regime. For the prompt emission, the KN effect may strongly suppress the IC component, which is consistent with one single spectral component seen in some strong bursts, such as in GRB080916C and GRB090217. The KN inverse-Compton cooling may also affect the low-energy electron number distribution and hence results in a low-energy synchrotron photon spectrum harder than the standard fast-cooling spectrum n({nu}){proportional_to}{nu}{sup -3/2}. During the early afterglow, KN effect leads to a low Compton-Y parameter, which is generally less than a few in the first tens of seconds for a wide range of parameter space. Furthermore, we suggest that the KN effect can explain the somewhat faster than expected decay of the early-time high-energy emission observed in some GRBs.

  12. Measurement of \\psi(3770) parameters

    E-Print Network [OSTI]

    Anashin, V V; Baldin, E M; Barladyan, A K; Barnyakov, A Yu; Barnyakov, M Yu; Baru, S E; Basok, I Yu; Beloborodova, O L; Blinov, A E; Blinov, V E; Bobrov, A V; Bobrovnikov, V S; Bogomyagkov, A V; Bondar, A E; Buzykaev, A R; Eidelman, S I; Grigoriev, D N; Glukhovchenko, Yu M; Gulevich, V V; Gusev, D V; Karnaev, S E; Karpov, G V; Karpov, S V; Kharlamova, T A; Kiselev, V A; Kolmogorov, V V; Kononov, S A; Kotov, K Yu; Kravchenko, E A; Kudryavtsev, V N; Kulikov, V F; Kurkin, G Ya; Kuper, E A; Levichev, E B; Maksimov, D A; Malyshev, V M; Maslennikov, A L; Medvedko, A S; Meshkov, O I; Mishnev, S I; Morozov, I I; Muchnoi, N Yu; Neufeld, V V; Nikitin, S A; Nikolaev, I B; Okunev, I N; Onuchin, A P; Oreshkin, S B; Orlov, I O; Osipov, A A; Peleganchuk, S V; Pivovarov, S G; Piminov, P A; Petrov, V V; Poluektov, A O; Prisekin, V G; Ruban, A A; Sandyrev, V K; Savinov, G A; Shamov, A G; Shatilov, D N; Shwartz, B A; Simonov, E A; Sinyatkin, S V; Skrinsky, A N; Smaluk, V V; Sokolov, A V; Sukharev, A M; Starostina, E V; Talyshev, A A; Tayursky, V A; Telnov, V I; Tikhonov, Yu A; Todyshev, K Yu; Tumaikin, G M; Usov, Yu V; Vorobiov, A I; Yushkov, A N; Zhilich, V N; Zhulanov, V V; Zhuravlev, A N

    2011-01-01T23:59:59.000Z

    We report the final results of a study of the \\psi(3770) meson using a data sample collected with the KEDR detector at the VEPP-4M electron-positron collider. The data analysis takes into account the interference between the resonant and nonresonant $D\\bar{D}$ production, where the latter is related to the nonresonant part of the energy-dependent form factor $F_D$. The vector dominance approach and several empirical parameterizations have been tried for the nonresonant $F_D^{\\NR}(s)$. Our results for the mass and total width of \\psi(3770) assuming \\psi(2S) dominance in $F_D^{\\NR}(s)$, are M = 3779.1 ^{+1.8}_{-1.7} +-0.6 ^{+0.2}_{-0.3} MeV/c^2, \\Gamma =25.2 ^{+4.6}_{-4.1} +-0.5 ^{+0.5}_{-0.2} MeV, where the first, second and third uncertainties are statistical, systematic and model, respectively. For the electron partial width two possible solutions have been found: (1) \\Gamma_{ee} = 147 ^{+97}_{-62} +- 13 ^{+11}_{-10} eV, (2) \\Gamma_{ee} = 415 ^{+59}_{-58} +- 38 ^{+160}_{-10} eV. Our statistics are insufficie...

  13. Nickel-based superalloy operating temperature determination via analysis of gamma/gamma' microstructure and coating/base material interdiffusion

    E-Print Network [OSTI]

    Ham, Wendy D. (Wendy Decker)

    2005-01-01T23:59:59.000Z

    The average operating temperature of RENÉ N5® high pressure turbine blades was evaluated via [gamma]/[gamma]' microstructure and coating/base metal interdiffusion methods. The [gamma]' volume fraction was measured by point ...

  14. Accessing the population of high redshift Gamma Ray Bursts

    E-Print Network [OSTI]

    Ghirlanda, G; Ghisellini, G; Mereghetti, S; Tagliaferri, G; Campana, S; Osborne, J P; O'Brien, P; Tanvir, N; Willingale, R; Amati, L; Basa, S; Bernardini, M G; Burlon, D; Covino, S; D'Avanzo, P; Frontera, F; Gotz, D; Melandri, A; Nava, L; Piro, L; Vergani, S D

    2015-01-01T23:59:59.000Z

    Gamma Ray Bursts (GRBs) are a powerful probe of the high redshift Universe. We present a tool to estimate the detection rate of high-z GRBs by a generic detector with defined energy band and sensitivity. We base this on a population model that reproduces the observed properties of GRBs detected by Swift, Fermi and CGRO in the hard X-ray and gamma-ray bands. We provide the expected cumulative distributions of the flux and fluence of simulated GRBs in different energy bands. We show that scintillator detectors, operating at relatively high energies (e.g. tens of keV to the MeV), can detect only the most luminous GRBs at high redshifts due to the link between the peak spectral energy and the luminosity (Ep-Liso) of GRBs. We show that the best strategy for catching the largest number of high-z bursts is to go softer (e.g. in the soft X-ray band) but with a very high sensitivity. For instance, an imaging soft X-ray detector operating in the 0.2-5 keV energy band reaching a sensitivity, corresponding to a fluence o...

  15. Gamma Radiation Effects on Physical, Optical, and Structural...

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

    Gamma Radiation Effects on Physical, Optical, and Structural Properties of Binary As-S glasses. Gamma Radiation Effects on Physical, Optical, and Structural Properties of Binary...

  16. aerial gamma spectrometry: Topics by E-print Network

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

    Gamma Mannheim, Universitt 3 Standard guide for high-resolution gamma-ray spectrometry of soil samples CERN Preprints Summary: 1.1 This guide covers the identification...

  17. Parallel Implementation of Gamma-Point Pseudopotential Plane...

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

    Parallel Implementation of Gamma-Point Pseudopotential Plane-Wave DFT with Exact Exchange. Parallel Implementation of Gamma-Point Pseudopotential Plane-Wave DFT with Exact...

  18. acute gamma radiation: Topics by E-print Network

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

    Published by The British Institute Pfeifer, Holger 4 Gravitational Radiation from Gamma-Ray Bursts Astrophysics (arXiv) Summary: Gamma Ray Bursts (GRBs) are the most relativistic...

  19. Measurement of main parameters of the \\psi(2S) resonance

    E-Print Network [OSTI]

    Anashin, V V; Baldin, E M; Barladyan, A K; Barnyakov, A Yu; Barnyakov, M Yu; Baru, S E; Basok, I Yu; Beloborodova, O L; Blinov, A E; Blinov, V E; Bobrov, A V; Bobrovnikov, V S; Bogomyagkov, A V; Bondar, A E; Buzykaev, A R; Eidelman, S I; Grigoriev, D N; Glukhovchenko, Yu M; Gulevich, V V; Gusev, D V; Karnaev, S E; Karpov, G V; Karpov, S V; Kharlamova, T A; Kiselev, V A; Kolmogorov, V V; Kononov, S A; Kotov, K Yu; Kravchenko, E A; Kudryavtsev, V N; Kulikov, V F; Kurkin, G Ya; Kuper, E A; Levichev, E B; Maksimov, D A; Malyshev, V M; Maslennikov, A L; Medvedko, A S; Meshkov, O I; Mishnev, S I; Morozov, I I; Muchnoi, N Yu; Neufeld, V V; Nikitin, S A; Nikolaev, I B; Okunev, I N; Onuchin, A P; Oreshkin, S B; Orlov, I O; Osipov, A A; Peleganchuk, S V; Pivovarov, S G; Piminov, P A; Petrov, V V; Poluektov, A O; Prisekin, V G; Ruban, A A; Sandyrev, V K; Savinov, G A; Shamov, A G; Shatilov, D N; Shwartz, B A; Simonov, E A; Sinyatkin, S V; Skrinsky, A N; Smaluk, V V; Sokolov, A V; Sukharev, A M; Starostina, E V; Talyshev, A A; Tayursky, V A; Telnov, V I; Tikhonov, Yu A; Todyshev, K Yu; Tumaikin, G M; Usov, Yu V; Vorobiov, A I; Yushkov, A N; Zhilich, V N; Zhulanov, V V; Zhuravlev, A N

    2011-01-01T23:59:59.000Z

    A high-precision determination of the main parameters of the \\psi(2S) resonance has been performed with the KEDR detector at the VEPP-4M e^{+}e^{-} collider in three scans of the \\psi(2S)--\\psi(3770) energy range. Fitting the energy dependence of the multihadron cross section in the vicinity of \\psi(2S) we obtained the mass value which is discussed in a separate paper and the product of the electron partial width by the branching fraction into hadrons \\Gamma_{ee}*B_{h} = 2.233 +- 0.015 +- 0.036 keV. Using the world average values of the electron and hadron branching fractions, one obtains the electron partial width and the total width of \\psi(2S): \\Gamma_{ee} =2.282 +- 0.015 +- 0.037 keV, \\Gamma = 296 +- 2 +- 8 keV. These results are consistent with and more than two times better than any of the previous experiments

  20. Derivation of a Multiparameter Gamma Model for Analyzing the Residence-Time Distribution Function for Nonideal Flow Systems as an Alternative to the Advection-Dispersion Equation

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

    Embry, Irucka; Roland, Victor; Agbaje, Oluropo; Watson, Valetta; Martin, Marquan; Painter, Roger; Byl, Tom; Sharpe, Lonnie

    2013-01-01T23:59:59.000Z

    A new residence-time distribution (RTD) function has been developed and applied to quantitative dye studies as an alternative to the traditional advection-dispersion equation (AdDE). The new method is based on a jointly combined four-parameter gamma probability density function (PDF). The gamma residence-time distribution (RTD) function and its first and second moments are derived from the individual two-parameter gamma distributions of randomly distributed variables, tracer travel distance, and linear velocity, which are based on their relationship with time. The gamma RTD function was used on a steady-state, nonideal system modeled as a plug-flow reactor (PFR) in the laboratory to validate themore »effectiveness of the model. The normalized forms of the gamma RTD and the advection-dispersion equation RTD were compared with the normalized tracer RTD. The normalized gamma RTD had a lower mean-absolute deviation (MAD) (0.16) than the normalized form of the advection-dispersion equation (0.26) when compared to the normalized tracer RTD. The gamma RTD function is tied back to the actual physical site due to its randomly distributed variables. The results validate using the gamma RTD as a suitable alternative to the advection-dispersion equation for quantitative tracer studies of non-ideal flow systems.« less

  1. Properties of the gamma function 

    E-Print Network [OSTI]

    Smith, William Boyce

    1960-01-01T23:59:59.000Z

    ( ) + Qr} converges if snd only if rsl Loci(&+g ) converges. r=l Oc& r=l formly over the set S if for each 6 + 0, there is sn in- teger Ng such that if 'n, v & gll ~ II, j. i+ u, te] ? Ogive', f, t]) & a, for sll z in S. l. lr. tn-teat). 1TL I...~~ (iiy. i Let ~&)= h~ %(&N}i Thus Euler's A(k} function gives s n~~ factorial when x is an integer, but does it give s factorial when x is not sn integer' ? To answer this we shall show the relation between Euler ~a snd the Gamma function. To do...

  2. Gamma-insensitive optical sensor

    DOE Patents [OSTI]

    Kruger, H.W.

    1994-03-15T23:59:59.000Z

    An ultraviolet/visible/infrared gamma-insensitive gas avalanche focal plane array is described comprising a planar photocathode and a planar anode pad array separated by a gas-filled gap and across which is applied an electric potential. Electrons ejected from the photocathode are accelerated sufficiently between collisions with the gas molecules to ionize them, forming an electron avalanche. The gap acts like a proportional counter. The array of anode pad are mounted on the front of an anode plate and are connected to matching contact pads on the back of the anode via feed through wires. Connection of the anode to signal processing electronics is made from the contact pads using standard indium bump techniques, for example. 6 figures.

  3. Strict Limit on CPT Violation from Polarization of Gamma-Ray Bursts

    E-Print Network [OSTI]

    Kenji Toma; Shinji Mukohyama; Daisuke Yonetoku; Toshio Murakami; Shuichi Gunji; Tatehiro Mihara; Yoshiyuki Morihara; Tomonori Sakashita; Takuya Takahashi; Yudai Wakashima; Hajime Yonemochi; Noriyuki Toukairin

    2012-11-09T23:59:59.000Z

    We report the strictest observational verification of CPT invariance in the photon sector, as a result of gamma-ray polarization measurement of distant gamma-ray bursts (GRBs), which are brightest stellar-size explosions in the universe. We detected the gamma-ray polarization of three GRBs with high significance, and the source distances may be constrained by a well-known luminosity indicator for GRBs. For the Lorentz- and CPT-violating dispersion relation E_{\\pm}^2=p^2 \\pm 2\\xi p^3/M_{Pl}, where \\pm denotes different circular polarization states of the photon, the parameter \\xi is constrained as |\\xi|

  4. Digitized two-parameter spectrometer for neutron-gamma mixed field

    SciTech Connect (OSTI)

    Matej, Z. [Faculty of Informatics, Masaryk Univ., Botanicka 68a, 602 00 Brno (Czech Republic); Cvachovec, J.; Prenosil, V. [Masaryk Univ., Brno (Czech Republic); Cvachovec, F. [Univ. of Defence, Brno (Czech Republic); Zaritski, S. [Kurchatov Inst., Moscow (Russian Federation)

    2011-07-01T23:59:59.000Z

    This paper shows the results of digital processing of output pulses from combined photon-neutron detector using a commercially available digitizer ACQUIRIS DP 210. The advantage of digital processing is reduction of the apparatus in weight and size, acceleration of measurement, and increased resistance to pile-up of pulses. The neutron and photon spectrum of radionuclide source {sup 252}Cf is presented. (authors)

  5. A new measurement of the rare decay eta -> pi^0 gamma gamma with the Crystal Ball/TAPS detectors at the Mainz Microtron

    SciTech Connect (OSTI)

    Nefkens, B. M.; Prakhov, S.; Aguar-Bartolom??, P.; Annand, J. R.; Arends, H. J.; Bantawa, K.; Beck, R.; Bekrenev, V.; Bergh??user, H.; Braghieri, A.; Briscoe, W. J.; Brudvik, J.; Cherepnya, S.; Codling, R. F.; Collicott, C.; Costanza, S.; Danilkin, I. V.; Denig, A.; Demissie, B.; Dieterle, M.; Downie, E. J.; Drexler, P.; Fil'kov, L. V.; Fix, A.; Garni, S.; Glazier, D. I.; Gregor, R.; Hamilton, D.; Heid, E.; Hornidge, D.; Howdle, D.; Jahn, O.; Jude, T. C.; Kashevarov, V. L.; K??ser, A.; Keshelashvili, I.; Kondratiev, R.; Korolija, M.; Kotulla, M.; Koulbardis, A.; Kruglov, S.; Krusche, B.; Lisin, V.; Livingston, K.; MacGregor, I. J.; Maghrbi, Y.; Mancel, J.; Manley, D. M.; McNicoll, E. F.; Mekterovic, D.; Metag, V.; Mushkarenkov, A.; Nikolaev, A.; Novotny, R.; Oberle, M.; Ortega, H.; Ostrick, M.; Ott, P.; Otte, P. B.; Oussena, B.; Pedroni, P.; Polonski, A.; Robinson, J.; Rosner, G.; Rostomyan, T.; Schumann, S.; Sikora, M. H.; Starostin, A.; Strakovsky, I. I.; Strub, T.; Suarez, I. M.; Supek, I.; Tarbert, C. M.; Thiel, M.; Thomas, A.; Unverzagt, M.; Watts, D. P.; Werthmueller, D; Witthauer, L.

    2014-08-01T23:59:59.000Z

    A new measurement of the rare, doubly radiative decay eta->pi^0 gamma gamma was conducted with the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. New data on the dependence of the partial decay width, Gamma(eta->pi^0 gamma gamma), on the two-photon invariant mass squared, m^2(gamma gamma), as well as a new, more precise value for the decay width, Gamma(eta->pi^0 gamma gamma) = (0.33+/-0.03_tot) eV, are based on analysis of 1.2 x 10^3 eta->pi^0 gamma gamma decays from a total of 6 x 10^7 eta mesons produced in the gamma p -> eta p reaction. The present results for dGamma(eta->pi^0 gamma gamma)/dm^2(gamma gamma) are in good agreement with previous measurements and recent theoretical calculations for this dependence.

  6. Search for the decays J/{psi}{yields}{gamma}{rho}{phi} and J/{psi}{yields}{gamma}{rho}{omega}

    SciTech Connect (OSTI)

    Ablikim, M.; Bai, J. Z.; Cai, X.; Chen, H. S.; Chen, H. X.; Chen, J. C.; Chen, Jin; Chen, Y. B.; Chu, Y. P.; Deng, Z. Y.; Du, S. X.; Fang, J.; Fang, S. S.; Gao, C. S.; Gu, S. D.; Guo, Y. N.; He, K. L.; Heng, Y. K.; Hu, H. M.; Hu, T. [Institute of High Energy Physics, Beijing 100049 (China)] (and others)

    2008-01-01T23:59:59.000Z

    Using 58x10{sup 6} J/{psi} events collected with the Beijing Spectrometer (BESII) at the Beijing Electron-Positron Collider, the decays J/{psi}{yields}{gamma}{phi}{rho} and J/{psi}{yields}{gamma}{omega}{rho} are searched for, and upper limits on their branching fractions are reported at the 90% C.L. No clear structures are observed in the {gamma}{rho}, {gamma}{phi}, or {rho}{phi} mass spectra for J/{psi}{yields}{gamma}{phi}{rho} nor in the {gamma}{rho}, {gamma}{omega}, or {rho}{omega} mass spectra for J/{psi}{yields}{gamma}{omega}{rho}.

  7. Direct measurement of the 15N(p,gamma)16O total cross section at novae energies

    E-Print Network [OSTI]

    D Bemmerer; A Caciolli; R Bonetti; C Broggini; F Confortola; P Corvisiero; H Costantini; Z Elekes; A Formicola; Zs Fulop; G Gervino; A Guglielmetti; C Gustavino; Gy Gyurky; M Junker; B Limata; M Marta; R Menegazzo; P Prati; V Roca; C Rolfs; C Rossi Alvarez; E Somorjai; O Straniero

    2009-02-04T23:59:59.000Z

    The 15N(p,gamma)16O reaction controls the passage of nucleosynthetic material from the first to the second carbon-nitrogen-oxygen (CNO) cycle. A direct measurement of the total 15N(p,gamma)16O cross section at energies corresponding to hydrogen burning in novae is presented here. Data have been taken at 90-230 keV center-of-mass energy using a windowless gas target filled with nitrogen of natural isotopic composition and a bismuth germanate summing detector. The cross section is found to be a factor two lower than previously believed.

  8. A high-Q^2 measurement of the photon structure function F_2^gamma at LEP2

    E-Print Network [OSTI]

    R. J. Taylor

    2000-10-05T23:59:59.000Z

    The photon structure function F_2^gamma has been measured at of 706 GeV^2, using a sample of two-photon events with a scattered electron observed in the OPAL electromagnetic endcap calorimeter. The data were taken during the years 1997-1999, when LEP operated at e+e- centre-of-mass energies ranging from 183 to 202 GeV, and correspond to an integrated luminosity of 424 pb^-1. This analysis represents the highest measurement of F_2^gamma made to date.

  9. A separation of electrons and protons in the GAMMA-400 gamma-ray telescope

    E-Print Network [OSTI]

    Leonov, A A; Bonvicini, V; Topchiev, N P; Adriani, O; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Bergstrom, L; Berti, E; Bigongiari, G; Bobkov, S G; Boezio, M; Bogomolov, E A; Bonechi, S; Bongi, M; Bottai, S; Castellini, G; Cattaneo, P W; Cumani, P; Dedenko, G L; De Donato, C; Dogiel, V A; Gorbunov, M S; Gusakov, Yu V; Hnatyk, B I; Kadilin, V V; Kaplin, V A; Kaplun, A A; Kheymits, M D; Korepanov, V E; Larsson, J; Loginov, V A; Longo, F; Maestro, P; Marrocchesi, P S; Mikhailov, V V; Mocchiutti, E; Moiseev, A A; Mori, N; Moskalenko, I V; Naumov, P Yu; Papini, P; Pearce, M; Picozza, P; Popov, A V; Rappoldi, A; Ricciarini, S; Runtso, M F; Ryde, F; Serdin, O V; Sparvoli, R; Spillantini, P; Suchkov, S I; Tavani, M; Taraskin, A A; Tiberio, A; Tyurin, E M; Ulanov, M V; Vacchi, A; Vannuccini, E; Vasilyev, G I; Yurkin, Yu T; Zampa, N; Zirakashvili, V N; Zverev, V G

    2015-01-01T23:59:59.000Z

    The GAMMA-400 gamma-ray telescope is intended to measure the fluxes of gamma rays and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV. Such measurements concern with the following scientific goals: search for signatures of dark matter, investigation of gamma-ray point and extended sources, studies of the energy spectra of Galactic and extragalactic diffuse emission, studies of gamma-ray bursts and gamma-ray emission from the active Sun, as well as high-precision measurements of spectra of high-energy electrons and positrons, protons, and nuclei up to the knee. The main components of cosmic rays are protons and helium nuclei, whereas the part of lepton component in the total flux is ~10E-3 for high energies. In present paper, the capability of the GAMMA-400 gamma-ray telescope to distinguish electrons and positrons from protons in cosmic rays is investigated. The individual contribution to the proton rejection is studied for each detector system of the GAMMA-400 gamma-ray tel...

  10. Neutron Resonance Parameters and Covariance Matrix of 239Pu

    SciTech Connect (OSTI)

    Derrien, Herve [ORNL; Leal, Luiz C [ORNL; Larson, Nancy M [ORNL

    2008-08-01T23:59:59.000Z

    In order to obtain the resonance parameters in a single energy range and the corresponding covariance matrix, a reevaluation of 239Pu was performed with the code SAMMY. The most recent experimental data were analyzed or reanalyzed in the energy range thermal to 2.5 keV. The normalization of the fission cross section data was reconsidered by taking into account the most recent measurements of Weston et al. and Wagemans et al. A full resonance parameter covariance matrix was generated. The method used to obtain realistic uncertainties on the average cross section calculated by SAMMY or other processing codes was examined.

  11. Escape of VHE gamma-rays from close massive binary Cen X-3

    E-Print Network [OSTI]

    W. Bednarek

    2000-07-13T23:59:59.000Z

    We consider propagation of very high energy (VHE) gamma-rays in the radiation field of a massive star in the binary system Cen X-3, which has been reported as a source of gamma-ray photons in the GeV and TeV energies. VHE gamma-rays or electrons, injected by the compact object, should develop inverse Compton pair cascades. We predict the gamma-ray spectra and light curves for the parameters of Cen X-3 system. It is found that the gamma-ray spectra, observed at different directions, have different shape and intensity. The gamma-ray light curves, produced in the case of electron injection by the compact object in the Cen X-3 system, should have opposite tendencies for photons with energies above 100 MeV and above 300 GeV, i.e. the photon intensities increases with phase in the first case and decreases with phase in the second case. However the model with injection of primary electrons seems to be in contrary with the reported modulation of the GeV gamma-ray flux with the pulsar's period. The model with injection of primary photons allows such modulation with the pulsar's period, but predicts strong modulation of the TeV flux with the orbital period of the binary. Modulation of TeV emission with the orbital period has been reported by the early Cherenkov observations, but was not confirmed by the recent, more sensitive observations by the Durham Mark 6 telescope.

  12. Resonant Propagation of Entangled Rhodium Mossbauer Gammas

    E-Print Network [OSTI]

    Yao Cheng; Zhongming Wang

    2006-10-19T23:59:59.000Z

    We report the resonant propagation of the long-lived Mossbauer gamma in the time-resolved Mossbauer spectroscopy. Recently, three entangled gammas emitted from the E3 rhodium Mossbauer transition has been proposed to interpret the extraordinary observations in the previous report. Further observation reported here is the dynamic beat of these entangled gammas at room temperature and 77K. Apparent beat anisotropy reveals their long-distance resonant propagation, which leads to suppressed Doppler shift of entangled photon transport in the Borrmann channel.

  13. Resonant Propagation of Entangled Rhodium Mossbauer Gammas

    E-Print Network [OSTI]

    Cheng, Y; Cheng, Yao; Wang, Zhongming

    2006-01-01T23:59:59.000Z

    We report the resonant propagation of the long-lived Mossbauer gamma in the time-resolved Mossbauer spectroscopy. Recently, three entangled gammas emitted from the E3 rhodium Mossbauer transition has been proposed to interpret the extraordinary observations in the previous report. Further observation reported here is the dynamic beat of these entangled gammas at room temperature and 77K. Apparent beat anisotropy reveals their long-distance resonant propagation, which leads to suppressed Doppler shift of entangled photon transport in the Borrmann channel.

  14. Gamma-Ray Bursts and Particle Astrophysics

    E-Print Network [OSTI]

    B. Gendre

    2008-07-24T23:59:59.000Z

    Gamma-ray bursts are violent events occurring randomly in the sky. In this review, I will present the fireball model, proposed to explain the phenomenon of gamma-ray bursts. This model has important consequences for the production and observation at Earth of gravitational waves, high energy neutrinos, cosmic rays and high energy photons, and the second part of this review will be focused on these aspects. A last section will briefly discuss the topic of the use of gamma-ray bursts as standard candles and possible cosmological studies.

  15. Bounds on Quantum Multiple-Parameter Estimation with Gaussian State

    E-Print Network [OSTI]

    Yang Gao; Hwang Lee

    2014-07-28T23:59:59.000Z

    We investigate the quantum Cramer-Rao bounds on the joint multiple-parameter estimation with the Gaussian state as a probe. We derive the explicit right logarithmic derivative and symmetric logarithmic derivative operators in such a situation. We compute the corresponding quantum Fisher information matrices, and find that they can be fully expressed in terms of the mean displacement and covariance matrix of the Gaussian state. Finally, we give some examples to show the utility of our analytical results.

  16. How precisely neutrino emission from supernova remnants can be constrained by gamma ray observations?

    E-Print Network [OSTI]

    F. L. Villante; F. Vissani

    2008-07-25T23:59:59.000Z

    We propose a conceptually and computationally simple method to evaluate the neutrinos emitted by supernova remnants using the observed gamma-ray spectrum. The proposed method does not require any preliminary parametrization of the gamma ray flux; the gamma ray data can be used as an input. In this way, we are able to propagate easily the observational errors and to understand how well the neutrino flux and the signal in neutrino telescopes can be constrained by gamma-ray data. We discuss the various possible sources of theoretical and systematical uncertainties (e.g., neutrino oscillation parameters, hadronic modeling, etc.), obtaining an estimate of the accuracy of our calculation. Furthermore, we apply our approach to the supernova remnant RX J1713.7-3946, showing that neutrino emission is very-well constrained by the H.E.S.S. gamma-ray data: indeed, the accuracy of our prediction is limited by theoretical uncertainties. Neutrinos from RX J1713.7-3946 can be detected with an exposure of the order km^2 year, provided that the detection threshold in future neutrino telescopes will be equal to about 1 TeV.

  17. Criticality parameters for tank waste evaluation

    SciTech Connect (OSTI)

    Rogers, C.A.

    1997-05-19T23:59:59.000Z

    Nuclear criticality parameters were developed as a basis for evaluating criticality safety for waste stored in the high-level waste tank farms on the Hanford Site in Washington State. The plutonium critical concentration and critical mass were calculated using a conservative waste model (CWM). The primary requirement of a CWM is that it have a lower neutron absorption than any actual waste. Graphs are provided of the critical mass as a function of plutonium concentration for spheres and for uniform slab layers in a 22.9-m-diameter tank. Minimum subcritical absorber-to-plutonium mass rates were calculated for waste components selected for their relative abundance and neutron absorption capacity. Comparison of measured absorber-to-plutonium mass ratios in their corresponding subcritical limit mass ratios provides a means of assessing whether criticality is possible for waste of the measured composition. A comparison is made between the plutonium critical concentrations in CWM solids and in a postulated real waste. This comparison shows that the actual critical parameters are likely to be significantly larger than those obtained using the CWM, thus providing confidence that the margin of safety obtained to the criticality safety evaluation is conservative.

  18. Time-Dependent CP Asymmetries in B0 -> Ks Pi0 gamma transition

    E-Print Network [OSTI]

    K. Abe; for the Belle Collaboration

    2005-07-13T23:59:59.000Z

    We present measurements of CP-violation parameters in b -> s gamma transitions based on a sample of 386x10^6 BB pairs collected at the Y(4S) resonance with the Belle detector at the KEKB energy-asymmetric e+e- collider. One neutral B meson is fully reconstructed in the B0 -> Ks Pi0 gamma decay channel irrespective to the Ks Pi0 intermediate state. The flavor of the accompanying B meson is identified from its decay products. CP-violation parameters are obtained from the asymmetries in the distributions of the proper-time intervals between the two B decays. We obtain the following results for the Ks Pi0 invariant mass covering the full range up to 1.8 GeV/c^2: S_{Ks Pi0 gamma} = +0.08 +-0.41(stat) +-0.10(syst), A_{Ks Pi0 gamma} = +0.12 +-0.27(stat) +-0.10(syst).

  19. DISCOVERY OF TeV GAMMA-RAY EMISSION FROM CTA 1 BY VERITAS

    SciTech Connect (OSTI)

    Aliu, E.; Errando, M. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States)] [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Archambault, S. [Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada)] [Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada); Arlen, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)] [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Aune, T.; Bouvier, A. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States)] [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R. [Department of Physics, Washington University, St. Louis, MO 63130 (United States)] [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States)] [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Cesarini, A.; Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland)] [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States)] [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Collins-Hughes, E. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)] [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Cui, W. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States)] [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Duke, C. [Department of Physics, Grinnell College, Grinnell, IA 50112-1690 (United States)] [Department of Physics, Grinnell College, Grinnell, IA 50112-1690 (United States); Dumm, J. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)] [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Dwarkadas, V. V. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)] [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Falcone, A., E-mail: muk@astro.columbia.edu, E-mail: smcarthur@ulysses.uchicago.edu [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); and others

    2013-02-10T23:59:59.000Z

    We report the discovery of TeV gamma-ray emission coincident with the shell-type radio supernova remnant (SNR) CTA 1 using the VERITAS gamma-ray observatory. The source, VER J0006+729, was detected as a 6.5 standard deviation excess over background and shows an extended morphology, approximated by a two-dimensional Gaussian of semimajor (semiminor) axis 0. Degree-Sign 30 (0. Degree-Sign 24) and a centroid 5' from the Fermi gamma-ray pulsar PSR J0007+7303 and its X-ray pulsar wind nebula (PWN). The photon spectrum is well described by a power-law dN/dE = N {sub 0}(E/3 TeV){sup -{Gamma}}, with a differential spectral index of {Gamma} = 2.2 {+-} 0.2{sub stat} {+-} 0.3{sub sys}, and normalization N {sub 0} = (9.1 {+-} 1.3{sub stat} {+-} 1.7{sub sys}) Multiplication-Sign 10{sup -14} cm{sup -2} s{sup -1} TeV{sup -1}. The integral flux, F {sub {gamma}} = 4.0 Multiplication-Sign 10{sup -12} erg cm{sup -2} s{sup -1} above 1 TeV, corresponds to 0.2% of the pulsar spin-down power at 1.4 kpc. The energetics, colocation with the SNR, and the relatively small extent of the TeV emission strongly argue for the PWN origin of the TeV photons. We consider the origin of the TeV emission in CTA 1.

  20. Thermal evolution behavior of carbides and {gamma} Prime precipitates in FGH96 superalloy powder

    SciTech Connect (OSTI)

    Zhang Lin, E-mail: zhanglincsu@163.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Liu Hengsan, E-mail: lhsj63@sohu.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); He Xinbo, E-mail: xb_he@163.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Rafi-ud-din, E-mail: rafiuddi@gmail.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Qu Xuanhui, E-mail: quxh@ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Qin Mingli, E-mail: mlqin75@hotmail.com [State Key Laboratory for Advanced Metals and Materials, Beijing Key Laboratory for Powder Metallurgy and Particulate Materials, University of Science and Technology Beijing, Beijing, 100083 (China); Li Zhou, E-mail: zhouli621@126.com [National Key Lab of High Temperature Structural Materials, Beijing Institute of Aeronautical Materials, Beijing, 100095 (China); Zhang Guoqing, E-mail: g.zhang@126.com [National Key Lab of High Temperature Structural Materials, Beijing Institute of Aeronautical Materials, Beijing, 100095 (China)

    2012-05-15T23:59:59.000Z

    The characteristics of rapidly solidified FGH96 superalloy powder and the thermal evolution behavior of carbides and {gamma} Prime precipitates within powder particles were investigated. It was observed that the reduction of powder size and the increase of cooling rate had transformed the solidification morphologies of atomized powder from dendrite in major to cellular structure. The secondary dendritic spacing was measured to be 1.02-2.55 {mu}m and the corresponding cooling rates were estimated to be in the range of 1.4 Multiplication-Sign 10{sup 4}-4.7 Multiplication-Sign 10{sup 5} K{center_dot}s{sup -1}. An increase in the annealing temperature had rendered the phase transformation of carbides evolving from non-equilibrium MC Prime carbides to intermediate transition stage of M{sub 23}C{sub 6} carbides, and finally to thermodynamically stable MC carbides. The superfine {gamma} Prime precipitates were formed at the dendritic boundaries of rapidly solidified superalloy powder. The coalescence, growth, and homogenization of {gamma}' precipitates occurred with increasing annealing temperature. With decreasing cooling rate from 650 Degree-Sign C{center_dot}K{sup -1} to 5 Degree-Sign C{center_dot}K{sup -1}, the morphological development of {gamma} Prime precipitates had been shown to proceed from spheroidal to cuboidal and finally to solid state dendrites. Meanwhile, a shift had been observed from dendritic morphology to recrystallized structure between 900 Degree-Sign C and 1050 Degree-Sign C. Moreover, accelerated evolution of carbides and {gamma}' precipitates had been facilitated by the formation of new grain boundaries which provide fast diffusion path for atomic elements. - Highlights: Black-Right-Pointing-Pointer Microstructural characteristic of FGH96 superalloy powder was investigated. Black-Right-Pointing-Pointer The relation between microstructure, particle size, and cooling rate was studied. Black-Right-Pointing-Pointer Thermal evolution behavior of {gamma} Prime and carbides in loose FGH96 powder was studied.

  1. Results from the Milagro Gamma-Ray Observatory

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    V energies, and a search for transient emission above 100 GeV from gamma-ray bursts. 1 Introduction remnants and gamma-ray bursts (GRB). Gamma rays are also produced when high-energy cosmic rays interactResults from the Milagro Gamma-Ray Observatory E. Blaufuss for the Milagro Collaboration a,1 , a

  2. Gravitational waves and gamma-ray bursts

    E-Print Network [OSTI]

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

    2012-05-11T23:59:59.000Z

    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.

  3. Studying Gamma Ray Bursts from a

    E-Print Network [OSTI]

    ?umer, Slobodan

    Studying Gamma Ray Bursts from a new perspective! {... Unraveling some mysteries and adding new Radio Op0cal X-ray Short ( energy -ray photons... ... accompained by a considerable long las0ng emission

  4. Airborne Gamma-Spectrometry in Switzerland

    SciTech Connect (OSTI)

    Butterweck, Gernot [Paul Scherrer Institut, 5232 Villigen PSI (Switzerland); Bucher, Benno [Swiss Federal Nuclear Safety Inspectorate, 5232 Villigen HSK (Switzerland); Rybach, Ladislaus [Swiss Federal Institute of Technology Zurich, Institute of Geophysics, 8093 Zurich (Switzerland)

    2008-08-07T23:59:59.000Z

    Airborne gamma-spectrometry is able to obtain fast radiological information over large areas. The airborne gamma-spectrometry unit deployed in Switzerland by the Swiss National Emergency Operations Centre (NEOC) consists of a Swiss army Super Puma helicopter equipped with four NaI-Detectors with a total volume of 17 liters, associated electronics and a real-time data evaluation and mapping unit developed by the Swiss Federal Institute of Technology (ETH) and the Paul Scherrer Institut (PSI). The operational readiness of the airborne gamma-spectrometry system is validated in annual exercises of one week duration. Data from 2005 and 2006 exercises are represented in maps of {sup 137}Cs activity concentration for two towns located in southern and western Switzerland. An indicator of man-made radioactivity (MMGC ratio) is demonstrated for an area with four different types of nuclear installations. The intercomparison between airborne gamma-spectrometry and ground measurements showed good agreement between both methods.

  5. Gamma-Ray Pulsar Studies With GLAST

    SciTech Connect (OSTI)

    Thompson, D.J.; /NASA, Goddard

    2011-11-23T23:59:59.000Z

    Some pulsars have their maximum observable energy output in the gamma-ray band, offering the possibility of using these high-energy photons as probes of the particle acceleration and interaction processes in pulsar magnetospheres. After an extended hiatus between satellite missions, the recently-launched AGILE mission and the upcoming Gamma-ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) will allow gamma-ray tests of the theoretical models developed based on past discoveries. With its greatly improved sensitivity, better angular resolution, and larger energy reach than older instruments, GLAST LAT should detect dozens to hundreds of new gamma-ray pulsars and measure luminosities, light curves, and phase-resolved spectra with unprecedented resolution. It will also have the potential to find radio-quiet pulsars like Geminga, using blind search techniques. Cooperation with radio and X-ray pulsar astronomers is an important aspect of the LAT team's planning for pulsar studies.

  6. Mining Gamma-Ray Burst Data

    E-Print Network [OSTI]

    Jon Hakkila; Richard J. Roiger; David J. Haglin; Robert S. Mallozzi; Geoffrey N. Pendleton; Charles A. Meegan

    2000-11-30T23:59:59.000Z

    Gamma-ray bursts provide what is probably one of the messiest of all astrophysical data sets. Burst class properties are indistinct, as overlapping characteristics of individual bursts are convolved with effects of instrumental and sampling biases. Despite these complexities, data mining techniques have allowed new insights to be made about gamma-ray burst data. We demonstrate how data mining techniques have simultaneously allowed us to learn about gamma-ray burst detectors and data collection, cosmological effects in burst data, and properties of burst subclasses. We discuss the exciting future of this field, and the web-based tool we are developing (with support from the NASA AISR Program). We invite others to join us in AI-guided gamma-ray burst classification (http://grb.mnsu.edu/grb/).

  7. The HAWC Gamma-Ray Observatory: Sensitivity to Steady and Transient Sources of Gamma Rays

    E-Print Network [OSTI]

    Abeysekara, A U; Alvarez, C; Álvarez, J D; Arceo, R; Arteaga-Velázquez, J C; Solares, H A Ayala; Barber, A S; Baughman, B M; Bautista-Elivar, N; Belmont, E; BenZvi, S Y; Berley, D; Rosales, M Bonilla; Braun, J; Caballero-Lopez, R A; Caballero-Mora, K S; Carramińana, A; Castillo, M; Cotti, U; Cotzomi, J; de la Fuente, E; De León, C; DeYoung, T; Hernandez, R Diaz; Díaz-Vélez, J C; Dingus, B L; DuVernois, M A; Ellsworth, R W; Fernandez, A; Fiorino, D W; Fraija, N; Galindo, A; Garfias, F; González, L X; González, M M; Goodman, J A; Grabski, V; Gussert, M; Hampel-Arias, Z; Hui, C M; Hüntemeyer, P; Imran, A; Iriarte, A; Karn, P; Kieda, D; Kunde, G J; Lara, A; Lauer, R J; Lee, W H; Lennarz, D; Vargas, H León; Linares, E C; Linnemann, J T; Longo, M; Luna-GarcIa, R; Marinelli, A; Martinez, H; Martinez, O; Martínez-Castro, J; Matthews, J A J; Miranda-Romagnoli, P; Moreno, E; Mostafá, M; Nava, J; Nellen, L; Newbold, M; Noriega-Papaqui, R; Oceguera-Becerra, T; Patricelli, B; Pelayo, R; Pérez-Pérez, E G; Pretz, J; Rivičre, C; Rosa-González, D; Salazar, H; Salesa, F; Sanchez, F E; Sandoval, A; Santos, E; Schneider, M; Silich, S; Sinnis, G; Smith, A J; Sparks, K; Springer, R W; Taboada, I; Toale, P A; Tollefson, K; Torres, I; Ukwatta, T N; Villaseńor, L; Weisgarber, T; Westerhoff, S; Wisher, I G; Wood, J; Yodh, G B; Younk, P W; Zaborov, D; Zepeda, A; Zhou, H

    2013-01-01T23:59:59.000Z

    The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory is designed to record air showers produced by cosmic rays and gamma rays between 100 GeV and 100 TeV. Because of its large field of view and high livetime, HAWC is well-suited to measure gamma rays from extended sources, diffuse emission, and transient sources. We describe the sensitivity of HAWC to emission from the extended Cygnus region as well as other types of galactic diffuse emission; searches for flares from gamma-ray bursts and active galactic nuclei; and the first measurement of the Crab Nebula with HAWC-30.

  8. Gamma Ray Bursts from Ordinary Cosmic Strings

    E-Print Network [OSTI]

    R. H. Brandenberger; A. T. Sornborger; M. Trodden

    1993-02-12T23:59:59.000Z

    We give an upper estimate for the number of gamma ray bursts from ordinary (non-superconducting) cosmic strings expected to be observed at terrestrial detectors. Assuming that cusp annihilation is the mechanism responsible for the bursts we consider strings arising at a GUT phase transition and compare our estimate with the recent BATSE results. Further we give a lower limit for the effective area of future detectors designed to detect the cosmic string induced flux of gamma ray bursts.

  9. Gamma-ray Albedo of the Moon

    SciTech Connect (OSTI)

    Moskalenko, Igor V.; Porter, Troy A.

    2007-06-14T23:59:59.000Z

    We use the GEANT4 Monte Carlo framework to calculate the gamma-ray albedo of the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our calculation of the albedo spectrum agrees with the EGRET data. We show that the spectrum of gamma-rays from the Moon is very steep with an effective cutoff around 3 GeV (600 MeV for the inner part of the Moon disc). Since it is the only (almost) black spot in the gamma-ray sky, it provides a unique opportunity for calibration of gamma-ray telescopes, such as the forthcoming Gamma Ray Large Area Space Telescope (GLAST). The albedo flux depends on the incident CR spectrum which changes over the solar cycle. Therefore, it is possible to monitor the CR spectrum using the albedo gamma-ray flux. Simultaneous measurements of CR proton and helium spectra by the Payload for Antimatter Matter Exploration and Light-nuclei Astrophysics (PAMELA), and observations of the albedo -rays by the GLAST Large Area Telescope (LAT), can be used to test the model predictions and will enable the GLAST LAT to monitor the CR spectrum near the Earth beyond the lifetime of PAMELA.

  10. Gamma-analysis of airborne particulates sampled in Youzhno-Sakhalinsk town at March - April 2011

    E-Print Network [OSTI]

    E. G. Tertyshnik; V. P. Martynenko; F. A. Andreev; G. B. Artemyev

    2012-03-22T23:59:59.000Z

    The experience of discovery of the radioactive products which have released into atmosphere of Sakhalin region from Fukushima Daiichi accident is presented. Sampling of airborne particulates and atmosphere fallout was carried out by means of the air ventilation set and horizontal gauze planchs, respectively. The HPGe detector was used for gamma analyses of the airborne samples. Since 23 March we confidently measured 131I in the airborne samples, after 03.04.2011 we also registered a rise of activity 137Cs and 134Cs. 132Te and 132I were discovered in ashen sample of the planch, which had exposed in Youzhno-Kurilk from 14 to 17 March. The effect of the pairs production when in the samples 208Tl presence, which emits gamma-quanta of 2615 keV, causes a rise in apparatus spectra of the peak corresponding to energy 1593 keV, which could be in error ascribed to 140La. It had been experimentally shown that the systematic reduction of 134Cs content in measuring samples due to effect of gamma - gamma coincidence did not exceed 7 % (for the detector and geometry of the measurement used).

  11. Differential Pair Distribution Function Study of the Structure of Arsenate Adsorbed on Nanocrystalline [gamma]-Alumina

    SciTech Connect (OSTI)

    Li, Wei; Harrington, Richard; Tang, Yuanzhi; Kubicki, James D.; Aryanpour, Masoud; Reeder, Richard J.; Parise, John B.; Phillips, Brian L. (SBU); (Penn)

    2012-03-15T23:59:59.000Z

    Structural information is important for understanding surface adsorption mechanisms of contaminants on metal (hydr)oxides. In this work, a novel technique was employed to study the interfacial structure of arsenate oxyanions adsorbed on {gamma}-alumina nanoparticles, namely, differential pair distribution function (d-PDF) analysis of synchrotron X-ray total scattering. The d-PDF is the difference of properly normalized PDFs obtained for samples with and without arsenate adsorbed, otherwise identically prepared. The real space pattern contains information on atomic pair correlations between adsorbed arsenate and the atoms on {gamma}-alumina surface (Al, O, etc.). PDF results on the arsenate adsorption sample on {gamma}-alumina prepared at 1 mM As concentration and pH 5 revealed two peaks at 1.66 {angstrom} and 3.09 {angstrom}, corresponding to As-O and As-Al atomic pair correlations. This observation is consistent with those measured by extended X-ray absorption fine structure (EXAFS) spectroscopy, which suggests a first shell of As-O at 1.69 {+-} 0.01 {angstrom} with a coordination number of 4 and a second shell of As-Al at 3.13 {+-} 0.04 {angstrom} with a coordination number of 2. These results are in agreement with a bidentate binuclear coordination environment to the octahedral Al of {gamma}-alumina as predicted by density functional theory (DFT) calculation.

  12. A morphological analysis of gamma-ray burst early optical afterglows

    E-Print Network [OSTI]

    Gao, He; Mészáros, Peter; Zhang, Bing

    2015-01-01T23:59:59.000Z

    Within the framework of the external shock model of gamma-ray bursts (GRBs) afterglows, we perform a morphological analysis of the early optical lightcurves to directly constrain model parameters. We define four morphological types, i.e. the reverse shock dominated cases with/without the emergence of the forward shock peak (Type I/ Type II), and the forward shock dominated cases without/with $\

  13. Measurement of the ratios of the Z/gamma* + >= n jet production cross sections to the total inclusive Z/gamma* cross section in p anti-p collisions at s**(1/2) = 1.96-TeV

    SciTech Connect (OSTI)

    Abazov, V.M.; Abbott, B.; Abolins, M.; Acharya, B.S.; Adams, M.; Adams, T.; Agelou, M.; Ahn, S.H.; Ahsan, M.; Alexeev, G.D.; Alkhazov, G.; /Buenos Aires U. /Rio de

    2006-08-01T23:59:59.000Z

    We present a study of events with Z bosons and jets produced at the Fermilab Tevatron Collider in p{bar p} collisions at a center of mass energy of 1.96 TeV. The data sample consists of nearly 14,000 Z/{gamma}* {yields} e{sup +}e{sup -} candidates corresponding to the integrated luminosity of 340 pb{sup -1} collected using the D0 detector. Ratios of the Z/{gamma}* + {ge} n jet cross sections to the total inclusive Z/{gamma}* cross section have been measured for n = 1 to 4 jet events. Our measurements are found to be in good agreement with a next-to-leading order QCD calculation and with a tree-level QCD prediction with parton shower simulation and hadronization.

  14. MAGNETIZATION DEGREE OF GAMMA-RAY BURST FIREBALLS: NUMERICAL STUDY

    SciTech Connect (OSTI)

    Harrison, Richard; Kobayashi, Shiho, E-mail: R.M.Harrison@2006.ljmu.ac.uk [Astrophysics Research Institute, Liverpool John Moores University, Liverpool, L3 5RF (United Kingdom)

    2013-08-01T23:59:59.000Z

    The relative strength between forward and reverse shock emission in early gamma-ray burst (GRB) afterglow reflects that of magnetic energy densities in the two shock regions. We numerically show that with the current standard treatment, the fireball magnetization is underestimated by up to two orders of magnitude. This discrepancy is especially large in the sub-relativistic reverse shock regime (i.e., the thin shell and intermediate regime), where most optical flashes were detected. We provide new analytic estimates of the reverse shock emission based on a better shock approximation, which well describe numerical results in the intermediate regime. We show that the reverse shock temperature at the onset of afterglow is constant, ( {Gamma}-bar{sub d}-1){approx}8 Multiplication-Sign 10{sup -2}, when the dimensionless parameter {xi}{sub 0} is more than several. Our approach is applied to case studies of GRB 990123 and 090102, and we find that magnetic fields in the fireballs are even stronger than previously believed. However, these events are still likely to be due to a baryonic jet with {sigma} {approx} 10{sup -3} for GRB 990123 and {approx}3 Multiplication-Sign 10{sup -4} to 3 for GRB 090102.

  15. Neutrino Emission from Gamma-Ray Burst Fireballs, Revised

    E-Print Network [OSTI]

    Svenja Hümmer; Philipp Baerwald; Walter Winter

    2012-05-02T23:59:59.000Z

    We review the neutrino flux from gamma-ray bursts, which is estimated from gamma-ray observations and used for the interpretation of recent IceCube data, from a particle physics perspective. We numerically calculate the neutrino flux for the same astrophysical assumptions as the analytical fireball neutrino model, including the dominant pion and kaon production modes, flavor mixing, and magnetic field effects on the secondary muons, pions, and kaons. We demonstrate that taking into account the full energy dependencies of all spectra, the normalization of the expected neutrino flux reduces by about one order of magnitude and the spectrum shifts to higher energies, where we can pin down the exact origin of the discrepancies by the re-computation of the analytical models. We also reproduce the IceCube-40 analysis for exactly the same bursts and same assumptions and illustrate the impact of uncertainties. We conclude that the baryonic loading of the fireballs, which is an important control parameter for the emission of cosmic rays, can be constrained significantly with the full-scale experiment after about ten years.

  16. A Tight $L_{\\rm p, iso}-E'_{\\rm p}-\\Gamma_0$ Correlation of Gamma-Ray Bursts

    E-Print Network [OSTI]

    Liang, En-Wei; LV, Jing; Lu, Ruijing; Zhang, Jin; Zhang, Bing

    2015-01-01T23:59:59.000Z

    We select a sample of 34 gamma-ray bursts (GRBs) whose $\\Gamma_0$ values are derived with the onset peak observed in the afterglow lightcurves (except for GRB 060218 whose $\\Gamma_0$ is estimated with its radio data), and investigate the correlations among $\\Gamma_0$, the isotropic peak luminosity ($L_{\\rm p, iso}$), and the peak energy of the $\

  17. The Universe Viewed in Gamma-Rays 1 Toward Ultra Short Gamma Ray Burst Ground Based De-

    E-Print Network [OSTI]

    Enomoto, Ryoji

    The Universe Viewed in Gamma-Rays 1 Toward Ultra Short Gamma Ray Burst Ground Based De- tection- liminary data taking started in November 2002. 1. Introduction Gamma-ray bursts observed with space Tcherenkovlightfromoneshower Few 100MeV gamma-rays Fig. 1. In an imaging telescope, -ray bursts should appear as a Cherenkov

  18. Achieving Higher Accuracy in the Gamma-Ray Spectrocopic Assay of Holdup

    SciTech Connect (OSTI)

    Russo, P.A.; Wenz, T.R.; Smith, S.E.; Harris, J.F.

    2000-09-01T23:59:59.000Z

    Gamma-ray spectroscopy is an important technique for the measurement of quantities of nuclear material holdup in processing equipment. Because the equipment in large facilities dedicated to uranium isotopic enrichment, uranium/plutonium scrap recovery or various stages of fuel fabrication is extensive, the total holdup may be large by its distribution alone, even if deposit thicknesses are small. Good accountability practices require unbiased measurements with uncertainties that are as small as possible. This paper describes new procedures for use with traditional holdup analysis methods based on gamma-ray spectroscopy. The procedures address the two sources of bias inherent in traditional gamma-ray measurements of holdup. Holdup measurements are performed with collimated, shielded gamma-ray detectors. The measurement distance is chosen to simplify the deposit geometry to that of a point, line or area. The quantitative holdup result is based on the net count rate of a representative gamma ray. This rate is corrected for contributions from room background and for attenuation by the process equipment. Traditional holdup measurements assume that the width of the point or line deposit is very small compared to the measurement distance, and that the self-attenuation effects can be neglected. Because each point or line deposit has a finite width and because self-attenuation affects all measurements, bias is incurred in both assumptions. In both cases the bias is negative, explaining the systematically low results of gamma-ray holdup measurements. The new procedures correct for bias that arises from both the finite-source effects and the gamma-ray self-attenuation. The procedures used to correct for both of these effects apply to the generalized geometries. One common empirical parameter is used for both corrections. It self-consistently limits the total error incurred (from uncertain knowledge of this parameter) in the combined correction process, so that it is compelling to use these procedures. The algorithms and the procedures are simple, general, and easily automated for use plant-wide. This paper shows the derivation of the new, generalized correction algorithms for finite-source and self-attenuation effects. It also presents an analysis of the sensitivity of the holdup result to the uncertainty in the empirical parameter when one or both corrections are made. The paper uses specific examples of the magnitudes of finite-source and self-attenuation corrections to measurements that were made in the field. It discusses the automated implementation of the correction procedure.

  19. Correspondence Useoilwealthtosave

    E-Print Network [OSTI]

    of Pretoria, South Africa. bernard.slippers@fabi.up.ac.za Priming-effect author responds I wish to clarify, such as the provision of sufficient clean energy, water and food (see go.nature. com/6rs2ih and go.nature. com and leadership. Basic personal engagement with the United Nations Millennium Development Goals, policy- makers

  20. Correspondence Researchistheseed

    E-Print Network [OSTI]

    Reynolds, John D.

    . Why should a small country spend scarce taxpayers' money on research and development (R. This is why the Irish government treats public spending on R&D as capital expenditure, as it does for roads and institutions. In developed countries, including Ireland, intellectual capital generally exceeds 80% of total

  1. * Corresponding author.

    E-Print Network [OSTI]

    unknown authors

    and data utility are often perceived to be at odds. An omniscient data source would have many the ability to compute the desired ‘‘beneficial outcome’ ’ of sharing data for mining without having to actually

  2. Propagation of Neutrinos through Magnetized Gamma-Ray Burst Fireball

    E-Print Network [OSTI]

    Sarira Sahu; Nissim Fraija; Yong-Yeon Keum

    2009-11-10T23:59:59.000Z

    The neutrino self-energy is calculated in a weakly magnetized plasma consists of electrons, protons, neutrons and their anti-particles and using this we have calculated the neutrino effective potential up to order $M^{-4}_W$. In the absence of magnetic field it reduces to the known result. We have also calculated explicitly the effective potentials for different backgrounds which may be helpful in different environments. By considering the mixing of three active neutrinos in the medium with the magnetic field we have derived the survival and conversion probabilities of neutrinos from one flavor to another and also the resonance condition is derived. As an application of the above, we considered the dense and relativistic plasma of the Gamma-Ray Bursts fireball through which neutrinos of 5-30 MeV can propagate and depending on the fireball parameters they may oscillate resonantly or non-resonantly from one flavor to another. These MeV neutrinos are produced due to stellar collapse or merger events which trigger the Gamma-Ray Burst. The fireball itself also produces MeV neutrinos due to electron positron annihilation, inverse beta decay and nucleonic bremsstrahlung. Using the three neutrino mixing and considering the best fit values of the neutrino parameters, we found that electron neutrinos are hard to oscillate to another flavors. On the other hand, the muon neutrinos and the tau neutrinos oscillate with equal probability to one another, which depends on the neutrino energy, temperature and size of the fireball. Comparison of oscillation probabilities with and without magnetic field shows that, they depend on the neutrino energy and also on the size of the fireball. By using the resonance condition, we have also estimated the resonance length of the propagating neutrinos as well as the baryon content of the fireball.

  3. Kinetics of hardness evolution during annealing of gamma-irradiated polycarbonate

    SciTech Connect (OSTI)

    Yeh, S. H.; Chen, P. Y.; Lee, Sanboh [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Harmon, Julie [Department of Chemistry, University of South Florida, Tampa, Florida 33620-5250 (United States)

    2012-12-01T23:59:59.000Z

    This study focuses on the evolution in microhardness values that accompany isothermal annealing in gamma-irradiated polycarbonate (PC). Hardness increases with increasing annealing time, temperature, and gamma radiation dose. A model composed of a mixture of first and zero order structure relaxation is proposed to interpret the hardness data. The rate constant data fit the Arrhenius equation, and the corresponding activation energy decreases with increasing dose. The extent of structural relaxation that controls the hardness in post-annealed PC increases with increasing annealing temperature and dose. The model demonstrates that hardness evolution in PC is an endothermic process. By contrast, when the model is applied to irradiated poly(methyl methacrylate) and hydroxyethyl methacrylate copolymer, hardness evolution is an exothermic process.

  4. Doppler effect of gamma-ray bursts in the fireball framework

    E-Print Network [OSTI]

    Yi-Ping Qin; Fu-Wen Zhang

    2004-07-13T23:59:59.000Z

    The influence of the Doppler effect in the fireball framework on the spectrum of gamma-ray bursts is investigated. The study shows that the shape of the expected spectrum of an expanding fireball remains almost the same as that of the corresponding rest frame spectrum for constant radiations of the bremsstrahlung, Comptonized, and synchrotron mechanisms as well as for that of the GRB model. The peak flux spectrum and the peak frequency are obviously correlated. When the value of the Lorentz factor becomes 10 times larger, the flux of fireballs would be several orders of magnitude larger. The expansion speed of fireballs is a fundamental factor of the enhancement of the flux of gamma-ray bursts.

  5. Exclusive search for Higgs boson to gamma-gamma decay via vector boson fusion production mechanism

    E-Print Network [OSTI]

    Rankin, Dylan Sheldon

    2012-01-01T23:59:59.000Z

    We perform an exclusive search for the Higgs boson to gamma-gamma decay via vector boson fusion. We utilize the characteristic features of vector boson fusion, such as the di-jet [Delta][eta] and mass, as well as the ...

  6. Characterization of the unfolding, refolding, and aggregation pathways of two protein implicated in cataractogenesis : human gamma D and human gamma S crystallin

    E-Print Network [OSTI]

    Kosinski-Collins, Melissa Sue, 1978-

    2005-01-01T23:59:59.000Z

    Human [gamma]D crystallin (H[gamma]D-Crys) and human [gamma]S crystallin (H[gamma]S-Crys), are major proteins of the human eye lens and are components of cataracts. H[gamma]D-Crys is expressed early in life in the lens ...

  7. Gamma-Ray Emission in Dissipative Pulsar Magnetospheres: From Theory to Fermi Observations

    E-Print Network [OSTI]

    Constantinos Kalapotharakos; Alice K. Harding; Demosthenes Kazanas

    2014-07-27T23:59:59.000Z

    We compute the patterns of $\\gamma$-ray emission due to curvature radiation in dissipative pulsar magnetospheres. Our ultimate goal is to construct macrophysical models that are able to reproduce the observed $\\gamma$-ray light-curve phenomenology recently published in the Second Fermi Pulsar Catalog. We apply specific forms of Ohm's law on the open field lines using a broad range for the macroscopic conductivity values that result in solutions ranging, from near-vacuum to near Force-Free. Using these solutions, we generate model $\\gamma$-ray light curves by calculating realistic trajectories and Lorentz factors of radiating particles, under the influence of both the accelerating electric fields and curvature radiation-reaction. We further constrain our models using the observed dependence of the phase-lags between the radio and $\\gamma$-ray emission on the $\\gamma$-ray peak-separation. We perform a statistical comparison of our model radio-lag vs peak-separation diagram and the one obtained for the Fermi standard pulsars. We find that for models of uniform conductivity over the entire open magnetic field line region, agreement with observations favors higher values of this parameter. We find, however, significant improvement in fitting the data with models that employ a hybrid form of conductivity; specifically, infinite conductivity interior to the light-cylinder and high but finite conductivity on the outside. In these models the $\\gamma$-ray emission is produced in regions near the equatorial current sheet but modulated by the local physical properties. These models have radio-lags near the observed values and statistically best reproduce the observed light-curve phenomenology. Additionally, these models produce GeV photon cut-off energies.

  8. Development of a database for prompt gamma-ray neutron activation analysis: Summary report of the third research coordination meeting

    SciTech Connect (OSTI)

    Lindstrom, Richard M.; Firestone, Richard B.; Pavi, ???

    2003-04-01T23:59:59.000Z

    The main discussions and conclusions from the Third Co-ordination Meeting on the Development of a Database for Prompt Gamma-ray Neutron Activation Analysis are summarized in this report. All results were reviewed in detail, and the final version of the TECDOC and the corresponding software were agreed upon and approved for preparation. Actions were formulated with the aim of completing the final version of the TECDOC and associated software by May 2003.

  9. Caudate nucleus infarction demonstrated by N-isopropyl-p iodoamphetamine SPECT imaging using a rotating gamma camera

    SciTech Connect (OSTI)

    Polak, J.F.; Mueller, S.P.; Holman, B.L.

    1986-10-01T23:59:59.000Z

    N-isopropyl p-iodoamphetamine (I-123 IMP) was used in two patients with previous unilateral basal ganglia infarcts documented by CT of the head. Tomographic images obtained with a commercially available rotating gamma camera equipped with a long-bore collimator showed corresponding areas of decreased uptake in the head of the caudate nuclei. Detection of such small areas of decreased perfusion is possible using SPECT and I-123 radiolabeled IMP.

  10. * Corresponding author -kfingerman@berkeley.edu 1 Integrating Water Sustainability into the Low Carbon Fuel Standard

    E-Print Network [OSTI]

    Kammen, Daniel M.

    * Corresponding author - kfingerman@berkeley.edu 1 Integrating Water Sustainability into the Low implications of bioenergy only take into account consumption by biorefineries. Because the feedstock

  11. Observation of the Crab Nebula in Soft Gamma Rays with the Nuclear Compton Telescope

    E-Print Network [OSTI]

    Bandstra, Mark ShenYu

    2010-01-01T23:59:59.000Z

    Gamma-ray bursts . . . . . . . . . . . . . . . . . . . 1.268] G. J. Fishman. The gamma-ray burst capabilities of BATSEOlson. Observations of Gamma- Ray Bursts of Cosmic Origin.

  12. Development of Superconducting High-Resolution Gamma-Ray Spectrometers for Nuclear Safeguards

    E-Print Network [OSTI]

    Dreyer, Jonathan

    2012-01-01T23:59:59.000Z

    Counting 2.4.3 High-Resolution Gamma Spectrometry 2.5coincidence counting and gamma spectrometry system (CANEGA)High-Resolution Gamma Spectrometry Isotopic correlation

  13. Low latency search for Gravitational waves from BH-NS binaries in coincidence with Short Gamma Ray Bursts

    E-Print Network [OSTI]

    Andrea Maselli; Valeria Ferrari

    2014-02-24T23:59:59.000Z

    We propose a procedure to be used in the search for gravitational waves from black hole-neutron star coalescing binaries, in coincidence with short gamma-ray bursts. It is based on two recently proposed semi-analytic fits, one reproducing the mass of the remnant disk surrounding the black hole which forms after the merging as a function of some binary parameters, the second relating the neutron star compactness, i.e. the ratio of mass and radius, with its tidal deformability. Using a Fisher matrix analysis and the two fits, we assign a probability that the emitted gravitational signal is associated to the formation of an accreting disk massive enough to supply the energy needed to power a short gamma ray burst. This information can be used in low-latency data analysis to restrict the parameter space searching for gravitational wave signals in coincidence with short gamma-ray bursts, and to gain information on the dynamics of the coalescing system and on the internal structure of the components. In addition, when the binary parameters will be measured with high accuracy, it will be possible to use this information to trigger the search for off-axis gamma-ray bursts afterglows.

  14. Inelastic Scatterings of Entangled Mossbauer Gammas

    E-Print Network [OSTI]

    Yao Cheng; Zhongming Wang

    2006-10-12T23:59:59.000Z

    We report the observation of the temperature-dependent inelastic scattering of three entangled Mossbauer gammas in the time-resolved Mossbauer spectroscopy. Recently, the long-lived E3 Mossbauer transition of rhodium generated by bremsstrahlung irradiation has been reported. Two kinds of X-rays with the fast decay are attributed to the tri-photon effect. They are tri-photon pile-up of rhodium K X-rays and the high-Z impurity K X-rays. Energy of the particular K emission is higher than the sum energy of two Mossbauer gammas. This letter reports new discoveries by cooling down the sample using liquid nitrogen, namely the collective anomalous emission of entangled Mossbauer gammas. The enhancement of inelastic scatterings at low temperature such as rhodium K satellites is attributed to this entanglement.

  15. Inelastic Scatterings of Entangled Mossbauer Gammas

    E-Print Network [OSTI]

    Cheng, Y; Cheng, Yao; Wang, Zhongming

    2006-01-01T23:59:59.000Z

    We report the observation of the temperature-dependent inelastic scattering of three entangled Mossbauer gammas in the time-resolved Mossbauer spectroscopy. Recently, the long-lived E3 Mossbauer transition of rhodium generated by bremsstrahlung irradiation has been reported. Two kinds of x rays with the fast decay are attributed to the tri-photon effect. They are tri-photon pile-up of rhodium K x rays and the high-Z impurity K x rays. Energy of the particular K emission is greater than the sum energy of two Mossbauer gammas. This letter reports new discoveries by cooling down the sample using liquid nitrogen, namely the collective anomalous emission of entangled Mossbauer gammas. The enhancement of inelastic scatterings at low temperature such as rhodium K satellites is attributed to this entanglement.

  16. Fermi Observations of Gamma-ray Bursts

    SciTech Connect (OSTI)

    Ohno, Masanori [Institute of Space and Astronautical Science, JAXA, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan)

    2010-10-15T23:59:59.000Z

    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, such as leptonic, hadronic and afterglow origin. The highest energy photon detected by Fermi gives a constraint on the bulk Lorentz factor of the ultra-relativistic jets of GRBs. The impact of the Fermi GRB observations extends not only to the GRB-related issues but also to the outside GRB physics, such as quantum gravity and model of the extra galactic background light.

  17. Apparatus and method for detecting gamma radiation

    DOE Patents [OSTI]

    Sigg, R.A.

    1994-12-13T23:59:59.000Z

    A high efficiency radiation detector is disclosed for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data. 4 figures.

  18. Apparatus and method for detecting gamma radiation

    DOE Patents [OSTI]

    Sigg, Raymond A. (Martinez, GA)

    1994-01-01T23:59:59.000Z

    A high efficiency radiation detector for measuring X-ray and gamma radiation from small-volume, low-activity liquid samples with an overall uncertainty better than 0.7% (one sigma SD). The radiation detector includes a hyperpure germanium well detector, a collimator, and a reference source. The well detector monitors gamma radiation emitted by the reference source and a radioactive isotope or isotopes in a sample source. The radiation from the reference source is collimated to avoid attenuation of reference source gamma radiation by the sample. Signals from the well detector are processed and stored, and the stored data is analyzed to determine the radioactive isotope(s) content of the sample. Minor self-attenuation corrections are calculated from chemical composition data.

  19. Tracy-Widom asymptotics for a random polymer model with gamma-distributed weights

    E-Print Network [OSTI]

    Neil O'Connell; Janosch Ortmann

    2014-08-22T23:59:59.000Z

    We establish Tracy-Widom asymptotics for the partition function of a random polymer model with gamma-distributed weights recently introduced by Sepp\\"al\\"ainen. We show that the partition function of this random polymer can be represented within the framework of the geometric RSK correspondence and consequently its law can be expressed in terms of Whittaker functions. This leads to a representation of the law of the partition function which is amenable to asymptotic analysis. In this model, the partition function plays a role analogous to the smallest eigenvalue in the Laguerre unitary ensemble of random matrix theory.

  20. Intermolecular potential parameters and combining rules determined from viscosity data

    SciTech Connect (OSTI)

    Bastien, Lucas A.J.; Price, Phillip N.; Brown, Nancy J.

    2010-05-07T23:59:59.000Z

    The Law of Corresponding States has been demonstrated for a number of pure substances and binary mixtures, and provides evidence that the transport properties viscosity and diffusion can be determined from a molecular shape function, often taken to be a Lennard-Jones 12-6 potential, that requires two scaling parameters: a well depth {var_epsilon}{sub ij} and a collision diameter {sigma}{sub ij}, both of which depend on the interacting species i and j. We obtain estimates for {var_epsilon}{sub ij} and {sigma}{sub ij} of interacting species by finding the values that provide the best fit to viscosity data for binary mixtures, and compare these to calculated parameters using several 'combining rules' that have been suggested for determining parameter values for binary collisions from parameter values that describe collisions of like molecules. Different combining rules give different values for {sigma}{sub ij} and {var_epsilon}{sub ij} and for some mixtures the differences between these values and the best-fit parameter values are rather large. There is a curve in ({var_epsilon}{sub ij}, {sigma}{sub ij}) space such that parameter values on the curve generate a calculated viscosity in good agreement with measurements for a pure gas or a binary mixture. The various combining rules produce couples of parameters {var_epsilon}{sub ij}, {sigma}{sub ij} that lie close to the curve and therefore generate predicted mixture viscosities in satisfactory agreement with experiment. Although the combining rules were found to underpredict the viscosity in most of the cases, Kong's rule was found to work better than the others, but none of the combining rules consistently yields parameter values near the best-fit values, suggesting that improved rules could be developed.

  1. PHYSICAL PARAMETERS OF STANDARD AND BLOWOUT JETS

    SciTech Connect (OSTI)

    Pucci, Stefano; Romoli, Marco [Department of Physics and Astronomy, University of Firenze, I-50121 Firenze (Italy); Poletto, Giannina [INAF-Arcetri Astrophysical Observatory, I-50125 Firenze (Italy); Sterling, Alphonse C., E-mail: stpucci@arcetri.astro.it [Space Science Office, NASA/MSFC, Huntsville, Al 35812 (United States)

    2013-10-10T23:59:59.000Z

    The X-ray Telescope on board the Hinode mission revealed the occurrence, in polar coronal holes, of much more numerous jets than previously indicated by the Yohkoh/Soft X-ray Telescope. These plasma ejections can be of two types, depending on whether they fit the standard reconnection scenario for coronal jets or if they include a blowout-like eruption. In this work, we analyze two jets, one standard and one blowout, that have been observed by the Hinode and STEREO experiments. We aim to infer differences in the physical parameters that correspond to the different morphologies of the events. To this end, we adopt spectroscopic techniques and determine the profiles of the plasma temperature, density, and outflow speed versus time and position along the jets. The blowout jet has a higher outflow speed, a marginally higher temperature, and is rooted in a stronger magnetic field region than the standard event. Our data provide evidence for recursively occurring reconnection episodes within both the standard and the blowout jet, pointing either to bursty reconnection or to reconnection occurring at different locations over the jet lifetimes. We make a crude estimate of the energy budget of the two jets and show how energy is partitioned among different forms. Also, we show that the magnetic energy that feeds the blowout jet is a factor of 10 higher than the magnetic energy that fuels the standard event.

  2. Nuclear Waste Technical Review Board Correspondence with the Department of Energy

    E-Print Network [OSTI]

    85 Appendix E Nuclear Waste Technical Review Board Correspondence with the Department of Energy #12;#12;Appendix E 87 Nuclear Waste Technical Review Board Correspondence with the Department of Energy I n of Energy's (DOE) Office of Civilian Radioactive Waste Management (OCRWM). The letters typically provide

  3. SAYA's head-eye coordination system Correspondence of image-width and angle

    E-Print Network [OSTI]

    Beimel, Amos

    SAYA's head-eye coordination system Correspondence of image-width and angle 335 - 359 [deg] 0 - 25 - 25 [deg] is input, head and eyes move to right side. b) If the angle within 335 - 359 [deg] is input, head and eyes move to left side. SAYA's head-eye coordination system Correspondence of image

  4. A supersymmetric model of gamma ray bursts

    E-Print Network [OSTI]

    L. Clavelli; G. Karatheodoris

    2005-08-08T23:59:59.000Z

    We propose a model for gamma ray bursts in which a star subject to a high level of fermion degeneracy undergoes a phase transition to a supersymmetric state. The burst is initiated by the transition of fermion pairs to sfermion pairs which, uninhibited by the Pauli exclusion principle, can drop to the ground state of minimum momentum through photon emission. The jet structure is attributed to the Bose statistics of sfermions whereby subsequent sfermion pairs are preferentially emitted into the same state (sfermion amplification by stimulated emission). Bremsstrahlung gamma rays tend to preserve the directional information of the sfermion momenta and are themselves enhanced by stimulated emission.

  5. Redshift indicators for gamma-ray bursts

    E-Print Network [OSTI]

    J-L. Atteia

    2005-05-04T23:59:59.000Z

    The measure of the distances and luminosities of gamma-ray bursts (GRBs) led to the discovery that many GRB properties are strongly correlated with their intrinsic luminosity, leading to the construction of reliable luminosity indicators. These GRB luminosity indicators have quickly found applications, like the construction of 'pseudo-redshifts', or the measure of luminosity distances, which can be computed independently of the measure of the redshift. In this contribution I discuss various issues connected with the construction of luminosity-redshift indicators for gamma-ray bursts.

  6. Gamma-Ray Burst observations with Fermi

    E-Print Network [OSTI]

    Bissaldi, Elisabetta; Omodei, Nicola; Vianello, Giacomo; von Kienlin, Andreas

    2015-01-01T23:59:59.000Z

    After seven years of science operation, the Fermi mission has brought great advances in the study of Gamma-ray Bursts (GRBs). Over 1600 GRBs have been detected by the Gamma-ray Burst Monitor, and more than 100 of these are also detected by the Large Area Telescope above 30 MeV. We will give an overview of these observations, presenting the common properties in the GRB temporal and spectral behavior at high energies. We will also highlight the unique characteristics of some individual bursts. The main physical implications of these results will be discussed, along with open questions regarding GRB modeling in their prompt and temporally-extended emission phases.

  7. Study of Active Shielding for {gamma} - Spectrometers

    SciTech Connect (OSTI)

    Bikit, I.; Mrdja, D.; Forkapic, S.; Todorovic, N.; Veskovic, M.; Slivka, J.; Conkic, Lj.; Krmar, M.; Varga, E. [Department of Physics, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovica 4, 21 000 Novi Sad (Serbia and Montenegro)

    2006-04-26T23:59:59.000Z

    The features of the ground located gamma ray spectrometer shielded passively with 12 cm of lead and actively by five 0.5m x 0.5m x 0.05m plastic veto shields are described. The detector mass related background was 0.345 C/kg s. The 511 keV annihilation line was reduced by the factor of 7 by the anticoincidence gate. It is shown that the plastic shields increase the neutron capture gamma line intensities due to neutron thermalization.

  8. Gamma-Ray Bursts: Jets and Energetics

    E-Print Network [OSTI]

    D. A. Frail

    2003-11-12T23:59:59.000Z

    The relativistic outflows from gamma-ray bursts are now thought to be narrowly collimated into jets. After correcting for this jet geometry there is a remarkable constancy of both the energy radiated by the burst and the kinetic energy carried by the outflow. Gamma-ray bursts are still the most luminous explosions in the Universe, but they release energies that are comparable to supernovae. The diversity of cosmic explosions appears to be governed by the fraction of energy that is coupled to ultra-relativistic ejecta.

  9. Status of the Milagro $\\gamma$ Ray Observatory

    E-Print Network [OSTI]

    Atkins, R; Berley, D; Chen, M L; Coyne, D G; Delay, R S; Dingus, B L; Dorfan, D E; Ellsworth, R W; Evans, D; Falcone, A D; Fleysher, L; Fleysher, R; Gisler, G; Goodman, J A; Haines, T J; Hoffman, C M; Hugenberger, S; Kelley, L A; Leonor, I; Macri, J R; McConnell, M; McCullough, J F; McEnery, J E; Miller, R S; Mincer, A I; Morales, M F; Némethy, P; Ryan, J M; Schneider, M; Shen, B; Shoup, A L; Sinnis, G; Smith, A J; Sullivan, G W; Thompson, T N; Tümer, T O; Wang, K; Wascko, M O; Westerhoff, S; Williams, D A; Yang, T; Yodh, G B

    2001-01-01T23:59:59.000Z

    The Milagro Gamma Ray Observatory is the world's first large-area water Cherenkov detector capable of continuously monitoring the sky at TeV energies. Located in northern New Mexico, Milagro will perform an all sky survey of the Northern Hemisphere at energies between ~250 GeV and 50 TeV. With a high duty cycle, large detector area (~5000 square meters), and a wide field-of-view (~1 sr), Milagro is uniquely capable of searching for transient and DC sources of high-energy gamma-ray emission. Milagro has been operating since February, 1999. The current status of the Milagro Observatory and initial results will be discussed.

  10. Status of the Milagro Gamma Ray Observatory

    E-Print Network [OSTI]

    R. Atkins; W. Benbow; D. Berley; M. -L. Chen; D. G. Coyne; R. S. Delay; B. L. Dingus; D. E. Dorfan; R. W. Ellsworth; D. Evans; A. Falcone; L. Fleysher; R. Fleysher; G. Gisler; J. A. Goodman; T. J. Haines; C. M. Hoffman; S. Hugenberger; L. A. Kelley; I. Leonor; J. Macri; M. McConnell; J. F. McCullough; J. E. McEnery; R. S. Miller; A. I. Mincer; M. F. Morales; P. Nemethy; J. M. Ryan; M. Schneider; B. Shen; A. Shoup; G. Sinnis; A. J. Smith; G. W. Sullivan; T. N. Thompson; O. T. Tumer; K. Wang; M. O. Wascko; S. Westerhoff; D. A. Williams; T. Yang; G. B. Yodh

    1999-06-24T23:59:59.000Z

    The Milagro Gamma Ray Observatory is the world's first large-area water Cherenkov detector capable of continuously monitoring the sky at TeV energies. Located in northern New Mexico, Milagro will perform an all sky survey of the Northern Hemisphere at energies between ~250 GeV and 50 TeV. With a high duty cycle, large detector area (~5000 square meters), and a wide field-of-view (~1 sr), Milagro is uniquely capable of searching for transient and DC sources of high-energy gamma-ray emission. Milagro has been operating since February, 1999. The current status of the Milagro Observatory and initial results will be discussed.

  11. Enhanced Gamma-Ray Emission from Neutron Unbound States Populated in Beta Decay

    E-Print Network [OSTI]

    Tain, J L; Algora, A; Agramunt, J; Rubio, B; Rice, S; Gelletly, W; Regan, P; Zakari-Issoufou, A -A; Fallot, M; Porta, A; Rissanen, J; Eronen, T; Aysto, J; Batist, L; Bowry, M; Bui, V M; Caballero-Folch, R; Cano-Ott, D; Elomaa, V -V; Estevez, E; Farrelly, G F; Garcia, A R; Gomez-Hornillos, B; Gorlychev, V; Hakala, J; Jordan, M D; Jokinen, A; Kolhinen, V S; Kondev, F G; Martinez, T; Mendoza, E; Moore, I; Penttila, H; Podolyak, Zs; Reponen, M; Sonnenschein, V; Sonzogni, A A

    2015-01-01T23:59:59.000Z

    Total absorption spectroscopy was used to investigate the beta-decay intensity to states above the neutron separation energy followed by gamma-ray emission in 87,88Br and 94Rb. Accurate results were obtained thanks to a careful control of systematic errors. An unexpectedly large gamma intensity was observed in all three cases extending well beyond the excitation energy region where neutron penetration is hindered by low neutron energy. The gamma branching as a function of excitation energy was compared to Hauser-Feshbach model calculations. For 87Br and 88Br the gamma branching reaches 57% and 20% respectively, and could be explained as a nuclear structure effect. Some of the states populated in the daughter can only decay through the emission of a large orbital angular momentum neutron with a strongly reduced barrier penetrability. In the case of neutron-rich 94Rb the observed 4.5% branching is much larger than the calculations performed with standard nuclear statistical model parameters, even after proper c...

  12. Neutrinos from Decaying Muons, Pions, Kaons and Neutrons in Gamma Ray Bursts

    E-Print Network [OSTI]

    Reetanjali Moharana; Nayantara Gupta

    2012-05-27T23:59:59.000Z

    In the internal shock model of gamma ray bursts ultrahigh energy muons, pions, neutrons and kaons are likely to be produced in the interactions of shock accelerated relativistic protons with low energy photons (KeV-MeV). These particles subsequently decay to high energy neutrinos/antineutrinos and other secondaries. In the high internal magnetic fields of gamma ray bursts, the ultrahigh energy charged particles ($\\mu^+$, $\\pi^+$, $K^+$) lose energy significantly due to synchrotron radiations before decaying into secondary high energy neutrinos and antineutrinos. The relativistic neutrons decay to high energy antineutrinos, protons and electrons. We have calculated the total neutrino flux (neutrino and antineutrino) considering the decay channels of ultrahigh energy muons, pions, neutrons and kaons. We have shown that the total neutrino flux generated in neutron decay can be higher than that produced in $\\mu^+$ and $\\pi^+$ decay. The charged kaons being heavier than pions, lose energy slowly and their secondary total neutrino flux is more than that from muons and pions at very high energy. Our detailed calculations on secondary particle production in $p\\gamma$ interactions give the total neutrino fluxes and their flavour ratios expected on earth. Depending on the values of the parameters (luminosity, Lorentz factor, variability time, spectral indices and break energy in the photon spectrum) of a gamma ray burst the contributions to the total neutrino flux from the decay of different particles (muon, pion, neutron and kaon) may vary and they would also be reflected on the neutrino flavour ratios.

  13. The effect of neutrinos on the initial fireballs in gamma-ray bursts

    E-Print Network [OSTI]

    Hylke B. J. Koers; Ralph A. M. J. Wijers

    2005-05-26T23:59:59.000Z

    We investigate the fate of very compact, sudden energy depositions that may lie at the origin of gamma-ray bursts. Following on from the work of Cavallo and Rees (1978), we take account of the much higher energies now believed to be involved. The main effect of this is that thermal neutrinos are present and energetically important. We show that these may provide sufficient cooling to tap most of the explosion energy. However, at the extreme energies usually invoked for gamma-ray bursts, the neutrino opacity suffices to prevent dramatic losses, provided that the heating process is sufficiently fast. In a generic case, a few tens of percent of the initial fireball energy will escape as an isotropic millisecond burst of thermal neutrinos with a temperature of about 60 MeV, which is detectable for nearby gamma-ray bursts and hypernovae. For parameters we find most likely for gamma-ray burst fireballs, the dominant processes are purely leptonic, and thus the baryon loading of the fireball does not affect our conclusions.

  14. Estimation of compact binary coalescense rates from short gamma-ray burst redshift measurements

    E-Print Network [OSTI]

    Alexander Dietz

    2011-04-15T23:59:59.000Z

    Short gamma-ray bursts are believed to originate from the merger of two compact objects. If this scenario is correct, these bursts will be accompanied by the emission of strong gravitational waves, detectable by current or planned GW detectors, such as LIGO and Virgo. No detection of a gravitational wave has been made up to date. In this paper I will use a set of observed redshift measurements of short gamma-ray bursts to fit a model in order to determine the rate of such merger events in the nearby universe. Various corrections will be included in that calculation, as the field-of-view of the satellite missions, the beaming factors of gamma-ray bursts and other parameters. The computed rate estimations will be compared to other rate estimations, based on observations on binary neutron stars and population synthesis models. Given the upper limit established by LIGO/Virgo measurements, it is possible to draw conclusions on the beaming angle of gamma-ray bursts.

  15. Observations of GRB 990123 by the Compton $\\gamma$-Ray Observatory

    E-Print Network [OSTI]

    Briggs, M S; Kippen, R M; Preece, R D; Kouveliotou, C; Van Paradijs, J; Share, G H; Murphy, R J; Matz, S M; Connors, A; Winkler, C; McConnell, M L; Ryan, J M; Williams, O R; Young, C A; Dingus, B L; Catelli, J R; Wijers, R A M J

    1999-01-01T23:59:59.000Z

    GRB 990123 was the first burst from which simultaneous optical, X-ray and gamma-ray emission was detected; its afterglow has been followed by an extensive set of radio, optical and X-ray observations. We have studied the gamma-ray burst itself as observed by the CGRO detectors. We find that gamma-ray fluxes are not correlated with the simultaneous optical observations, and the gamma-ray spectra cannot be extrapolated simply to the optical fluxes. The burst is well fit by the standard four-parameter GRB function, with the exception that excess emission compared to this function is observed below ~15 keV during some time intervals. The burst is characterized by the typical hard-to-soft and hardness-intensity correlation spectral evolution patterns. The energy of the peak of the nu f_nu spectrum, E_p, reaches an unusually high value during the first intensity spike, 1470 +/- 110 keV, and then falls to consistent with a power law with a photon index of about -3. By fluence, GRB 990123 is brighter than all but 0.4...

  16. Cosmic-ray induced gamma-ray emission from the starburst galaxy NGC 253

    SciTech Connect (OSTI)

    Wang, Xilu; Fields, Brian D. [Department of Astronomy, MC-221, 1002 W. Green Street, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2014-05-09T23:59:59.000Z

    Cosmic rays in galaxies interact with the interstellar medium and give us a direct view of nuclear and particle interactions in the cosmos. For example, cosmic-ray proton interactions with interstellar hydrogen produce gamma rays via PcrPism??{sup 0}???. For a 'normal' star-forming galaxy like the Milky Way, most cosmic rays escape the Galaxy before such collisions, but in starburst galaxies with dense gas and huge star formation rate, most cosmic rays do suffer these interactions [1,2]. We construct a 'thick-target' model for starburst galaxies, in which cosmic rays are accelerated by supernovae, and escape is neglected. This model gives an upper limit to the gamma-ray emission. Only two free parameters are involved in the model: cosmic-ray proton acceleration energy rate from supernova and the proton injection spectral index. The pionic gamma-radiation is calculated from 10 MeV to 10 TeV for the starburst galaxy NGC 253, and compared to Fermi and HESS data. Our model fits NGC 253 well, suggesting that cosmic rays in this starburst are in the thick target limit, and that this galaxy is a gamma-ray calorimeter.

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

    E-Print Network [OSTI]

    Pijushpani Bhattacharjee; Nayantara Gupta

    2003-05-12T23:59:59.000Z

    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.

  18. Spinar Paradigm and Gamma Ray Bursts Central Engine

    E-Print Network [OSTI]

    V. Lipunov; E. Gorbovskoy

    2007-11-02T23:59:59.000Z

    A spinar is a quasi-equilibrium collapsing object whose equilibrium is maintained by the balance of centrifugal and gravitational forces and whose evolution is determined by its magnetic field. The spinar quasi equilibrium model recently discussed as the course for extralong X-ray plateu in GRB (Lipunov & Gorbovskoy, 2007). We propose a simple non stationary three-parameter collapse model with the determining role of rotation and magnetic field in this paper. The input parameters of the theory are the mass, angular momentum, and magnetic field of the collapsar. The model includes approximate description of the following effects: centrifugal force, relativistic effects of the Kerr metrics, pressure of nuclear matter, dissipation of angular momentum due to magnetic field, decrease of the dipole magnetic moment due to compression and general-relativity effects (the black hole has no hare), neutrino cooling, time dilatation, and gravitational redshift. The model describes the temporal behavior of the central engine and demonstrates the qualitative variety of the types of such behavior in nature. We apply our approach to explain the observed features of gamma-ray bursts of all types. In particular, the model allows the phenomena of precursors, x-ray and optical bursts, and the appearance of a plateau on time scales of several thousand seconds to be unified.

  19. PoGOLite -The Polarised Gamma-ray Observer

    E-Print Network [OSTI]

    Haviland, David

    PoGOLite - The Polarised Gamma-ray Observer CECILIA MARINI BETTOLO Licentiate Thesis Stockholm, Sweden 2008 #12;#12;Licentiate Thesis PoGOLite - The Polarised Gamma-ray Observer Cecilia Marini Bettolo

  20. Picture of the Week: Gamma-ray bursts, infographic

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

    4 Gamma-ray bursts: infographic Gamma-ray bursts (GRBs) are the most powerful explosions in the universe. With the help of sophisticated instruments such as the ground based RAPTOR...

  1. aided collimation gamma: Topics by E-print Network

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

    23 24 25 Next Page Last Page Topic Index 1 Evidence For and Against Collimation of Gamma Ray Bursts Astrophysics (arXiv) Summary: The degree to which gamma ray bursts are...

  2. aux radiations gamma: Topics by E-print Network

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

    radiation studies. Inoue, Yoshiyuki 2014-01-01 3 Gravitational Radiation from Gamma-Ray Bursts Astrophysics (arXiv) Summary: Gamma Ray Bursts (GRBs) are the most relativistic...

  3. accrued complex gamma: Topics by E-print Network

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

    Sie, da? g p n Gamma Grassl, Markus 8 A Complexity-Brightness Correlation in Gamma Ray Bursts Astrophysics (arXiv) Summary: We observe strong correlations between the...

  4. TEMPORAL DECONVOLUTION STUDY OF LONG AND SHORT GAMMA-RAY BURST LIGHT CURVES

    SciTech Connect (OSTI)

    Bhat, P. N.; Briggs, Michael S.; Connaughton, Valerie; Paciesas, William; Burgess, Michael; Chaplin, Vandiver; Goldstein, Adam; Guiriec, Sylvain [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Kouveliotou, Chryssa; Fishman, Gerald [Space Science Office, VP62, NASA/Marshall Space Flight Center, Huntsville, AL 35812 (United States); Van der Horst, Alexander J.; Meegan, Charles A. [Center for Space Plasma and Aeronomic Research (CSPAR), Universities Space Research Association, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Bissaldi, Elisabetta [Institute of Astro and Particle Physics, University of Innsbruck, Technikerstr. 25, 6020 Innsbruck (Austria); Diehl, Roland; Foley, Suzanne; Greiner, Jochen; Gruber, David [Max-Planck-Institut fuer Extraterrestrische Physik, Giessenbachstrasse 1, 85748 Garching (Germany); Fitzpatrick, Gerard [School of Physics, University College Dublin, Belfield, Stillorgan Road, Dublin 4 (Ireland); Gibby, Melissa; Giles, Misty M. [Jacobs Technology, Inc., Huntsville, AL 35806 (United States); and others

    2012-01-10T23:59:59.000Z

    The light curves of gamma-ray bursts (GRBs) are believed to result from internal shocks reflecting the activity of the GRB central engine. Their temporal deconvolution can reveal potential differences in the properties of the central engines in the two populations of GRBs which are believed to originate from the deaths of massive stars (long) and from mergers of compact objects (short). We present here the results of the temporal analysis of 42 GRBs detected with the Gamma-ray Burst Monitor onboard the Fermi Gamma-ray Space Telescope. We deconvolved the profiles into pulses, which we fit with lognormal functions. The distributions of the pulse shape parameters and intervals between neighboring pulses are distinct for both burst types and also fit with lognormal functions. We have studied the evolution of these parameters in different energy bands and found that they differ between long and short bursts. We discuss the implications of the differences in the temporal properties of long and short bursts within the framework of the internal shock model for GRB prompt emission.

  5. Coincidence searches of gravitational waves and short gamma-ray bursts

    E-Print Network [OSTI]

    Andrea Maselli; Valeria Ferrari

    2014-05-28T23:59:59.000Z

    Black-hole neutron-star coalescing binaries have been invoked as one of the most suitable scenario to explain the emission of short gamma-ray bursts. Indeed, if the black-hole which forms after the merger, is surrounded by a massive disk, neutrino annihilation processes may produce high-energy and collimated electromagnetic radiation. In this paper, we devise a new procedure, to be used in the search for gravitational waves from black-hole-neutron-star binaries, to assign a probability that a detected gravitational signal is associated to the formation of an accreting disk, massive enough to power gamma-ray bursts. This method is based on two recently proposed semi-analytic fits, one reproducing the mass of the remnant disk surrounding the black hole as a function of some binary parameters, the second relating the neutron star compactness, with its tidal deformability. Our approach can be used in low-latency data analysis to restrict the parameter space searching for gravitational signals associated with short gamma-ray bursts, and to gain information on the dynamics of the coalescing system and on the neutron star equation of state.

  6. Shifted one-parameter supersymmetric family of quartic asymmetric double-well potentials

    E-Print Network [OSTI]

    H. C. Rosu; S. C. Mancas; P. Chen

    2014-07-06T23:59:59.000Z

    Extending our previous work (Rosu, Mancas, Chen, Ann.Phys. 343 (2014) 87-102), we define supersymmetric partner potentials through a particular Riccati solution of the form F(x)=(x-c)^2-1, where c is a real shift parameter, and work out the quartic double-well family of one-parameter isospectral potentials obtained by using the corresponding general Riccati solution. For these parametric double well potentials, we study how the localization properties of the two wells depend on the parameter of the potentials for various values of the shifting parameter. We also consider the supersymmetric parametric family of the first double-well potential in the Razavy chain of double well potentials corresponding to F(x)=(1/2)sinh 2x-2(1+sqrt 2)sinh 2x/[(1+sqrt 2) cosh 2x+1], both unshifted and shifted, to test and compare the localization properties

  7. Mechanism of the efficient quenching of tryptophan fluorescence in human gamma crystallin

    E-Print Network [OSTI]

    Chen, Jiejin, Ph. D. Massachusetts Institute of Technology

    2008-01-01T23:59:59.000Z

    Quenching of the fluorescence of buried tryptophans (Trps) is an important reporter of protein conformation. Human [gamma]D-crystallin (H[gamma]D-Crys) and human [gamma]S-crystallin (H[gamma]S-Crys) are both very stable ...

  8. High Efficiency of Gamma-Ray Bursts Revisited

    E-Print Network [OSTI]

    Y. C. Zou A; Z. G. Dai B

    2007-01-01T23:59:59.000Z

    efficiency of gamma-ray bursts by assuming that the ejecta from the central engine are equally massive and

  9. \\Gamma \\Gamma \\Gamma \\Gamma \\Gamma \\Gamma

    E-Print Network [OSTI]

    Mannheim, Universität

    Zachmann y \\Lambda RWTH Aachen y Universit¨ at Karlsruhe Lehrstuhl f¨ ur Informatik III Fakult¨ at f¨ ur

  10. High redshift Gamma-Ray Bursts

    E-Print Network [OSTI]

    Salvaterra, R

    2015-01-01T23:59:59.000Z

    Ten years of operations of the Swift satellite have allow us to collect a small sample of long Gamma-Ray Bursts (GRBs) at redshift larger than six. I will review here the present status of this research field and discuss the possible use of GRBs as a fundamental new tool to explore the early Universe, complementary to quasar and galaxy surveys.

  11. Delayed Nickel Decay in Gamma Ray Bursts

    E-Print Network [OSTI]

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

    2002-05-19T23:59:59.000Z

    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.

  12. Gamma-Ray Pulsars: Models and Predictions

    E-Print Network [OSTI]

    Alice K. Harding

    2000-12-12T23:59:59.000Z

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

  13. Beta and gamma decays April 9, 2002

    E-Print Network [OSTI]

    Landstreet, John D.

    Beta and gamma decays April 9, 2002 1 Simple Fermi theory of beta decay ² Beta decay is one by the emission of a positive or negative beta particle (positron or electron). To ensure conservation of lepton emitted in beta decay is a continuum of energies, up to a maximum value, with most emitted betas having

  14. Gamma-ray bursts: a Centauro's cry?

    E-Print Network [OSTI]

    Z. K. Silagadze

    2003-06-30T23:59:59.000Z

    A new candidate for the gamma-ray bursts central engine is proposed: if in some energetic cosmic event a macroscopic amount of bubbles of the disoriented chiral condensate can be formed, then their subsequent decays will produce a relativistic fireball without the baryon loading problem. The neutron star to strange star transition is considered as a candidate example of such cosmic event.

  15. Current segmented gamma-ray scanner technology

    SciTech Connect (OSTI)

    Bjork, C.W.

    1987-01-01T23:59:59.000Z

    A new generation of segmented gamma-ray scanners has been developed at Los Alamos for scrap and waste measurements at the Savannah River Plant and the Los Alamos Plutonium Facility. The new designs are highly automated and exhibit special features such as good segmentation and thorough shielding to improve performance.

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

    E-Print Network [OSTI]

    Tomonori Totani

    1999-04-13T23:59:59.000Z

    We argue that gamma-ray bursts (GRBs) may be the origin of the cosmic gamma-ray background radiation observed in GeV range. It has theoretically been discussed that protons may carry a much larger amount of energy than electrons in GRBs, and this large energy can be radiated in TeV range by synchrotron radiation of ultra-high-energy protons (\\sim 10^{20} eV). The possible detection of GRBs above 10 TeV suggested by the Tibet and HEGRA groups also supports this idea. If this is the case, most of TeV gamma-rays from GRBs are absorbed in intergalactic fields and eventually form GeV gamma-ray background, whose flux is in good agreement with the recent observation.

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

    SciTech Connect (OSTI)

    Tuschareon, S., E-mail: tuscharoen@hotmail.com; Limkitjaroenporn, P., E-mail: tuscharoen@hotmail.com; Kaewkhao, J., E-mail: tuscharoen@hotmail.com [Center of Excellence in Glass Technology and Materials Science (CEGM), Nakhon Pathom Rajabhat University, Nakhon Pathom, 73000, Thailand and Science Program, Faculty of Science and Technology, Nakhon Pathom Rajabhat University, Nakhon Pathom, 73000 (Thailand)

    2014-03-24T23:59:59.000Z

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

  18. Gamma-ray Sky Observed with Fermi Large Area Telescope

    E-Print Network [OSTI]

    Yamamoto, Hirosuke

    detection reported Flare activity reported via ATel Gamma Ray Bursts reported via GCN Giant MC imageGamma-ray Sky Observed with Fermi Large Area Telescope RESCEU Symposium on Astroparticle Physics) Measure the photon direction Identification of the gamma-ray shower 36 planes of Si strip detectors (228 m

  19. LATTICE DYNAMICS NUCLEAR RESONANCE ABSORPTION OF GAMMA-RADIATION

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    LATTICE DYNAMICS NUCLEAR RESONANCE ABSORPTION OF GAMMA-RADIATION AND COHERENT DECAY MODES Institut effets de correlation de paires. Abstract. -The cross-section for nuclear resonance absorption of gamma-radiation rksonnante des radiations gamma est en gBneral calculee en negligeant I'influence des phenomknes de coherence

  20. The Compton Effect--Compton Scattering and Gamma Ray Spectroscopy

    E-Print Network [OSTI]

    Dai, Pengcheng

    The Compton Effect-- Compton Scattering and Gamma Ray Spectroscopy by Dr. James E. Parks Department and procedures for measuring gamma-ray energy distributions, (7) to learn about photomultipliers the interactions of high energy, electromagnetic photon radiation with materials in general. Gamma rays are high

  1. The Biggest Bangs The Mystery of Gamma-Ray Bursts,

    E-Print Network [OSTI]

    Katz, Jonathan I.

    The Biggest Bangs The Mystery of Gamma-Ray Bursts, The Most Violent Explosions in The Universe J. I a Gamma-Ray Burst Kill the Dinosaurs? Will a Burst Kill Us? · Glossary · Sources · Index viii #12;Chapter of these four cameras recorded visible light from a gamma-ray burst as it was happening, which had been the holy

  2. Gamma-Ray Bursts Nuclear Test Ban Treaty, 1963

    E-Print Network [OSTI]

    Harrison, Thomas

    Lecture 18 Gamma-Ray Bursts #12;Nuclear Test Ban Treaty, 1963 First Vela satellite pair launched and their predecessors, Vela 4, discovered the first gamma-ray bursts. The discovery was announced by Klebesadel, Strong, and Olson (ApJ, 182, 85) in 1973. #12;First Gamma-Ray Burst The Vela 5 satellites functioned from July, 1969

  3. The Biggest Bangs The Mystery of Gamma-Ray Bursts,

    E-Print Network [OSTI]

    Katz, Jonathan I.

    The Biggest Bangs The Mystery of Gamma-Ray Bursts, The Most Violent Explosions in The Universe J. I. Did a Gamma-Ray Burst Kill the Dinosaurs? Will a Burst Kill Us? #15; Glossary #15; Sources #15; Index. On January 23, 1999, one of these four cameras recorded visible light from a gamma-ray burst

  4. GammaRay Bursts: Old and New JOCHEN GREINER

    E-Print Network [OSTI]

    Greiner, Jochen

    Gamma­Ray Bursts: Old and New JOCHEN GREINER Astrophysikalisches Institut Potsdam, 14482 Potsdam, Germany (jgreiner@aip.de) ABSTRACT. Gamma­ray bursts are sudden releases of energy that for a duration of a few seconds outshine even huge galaxies. 30 years after the first detection of a gamma­ray burst

  5. Observation of the radiative decay D*+-> D+gamma

    E-Print Network [OSTI]

    Ammar, Raymond G.; Baringer, Philip S.; Bean, Alice; Besson, David Zeke; Coppage, Don; Darling, C.; Davis, Robin E. P.; Kotov, S.; Kravchenko, I.; Kwak, Nowhan; Zhou, L.

    1998-05-01T23:59:59.000Z

    We have observed a signal for the decay D*(+) --> D(+)gamma at a significance of 4 standard deviations. From the measured branching ratio B(D*(+) --> D(+)gamma)/B(D*(+) --> D(+)pi(0)) = 0.055 +/- 0.014 +/- 0.010 we find B(D*(+) --> D(+)gamma) = 0...

  6. CONSTRAINTS ON THE SYNCHROTRON EMISSION MECHANISM IN GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Beniamini, Paz; Piran, Tsvi, E-mail: paz.beniamini@mail.huji.ac.il, E-mail: tsvi.piran@mail.huji.ac.il [Racah Institute for Physics, Hebrew University, Jerusalem 91904 (Israel)

    2013-05-20T23:59:59.000Z

    We reexamine the general synchrotron model for gamma-ray bursts' (GRBs') prompt emission and determine the regime in the parameter phase space in which it is viable. We characterize a typical GRB pulse in terms of its peak energy, peak flux, and duration and use the latest Fermi observations to constrain the high-energy part of the spectrum. We solve for the intrinsic parameters at the emission region and find the possible parameter phase space for synchrotron emission. Our approach is general and it does not depend on a specific energy dissipation mechanism. Reasonable synchrotron solutions are found with energy ratios of 10{sup -4} < {epsilon}{sub B}/{epsilon}{sub e} < 10, bulk Lorentz factor values of 300 < {Gamma} < 3000, typical electrons' Lorentz factor values of 3 Multiplication-Sign 10{sup 3} < {gamma}{sub e} < 10{sup 5}, and emission radii of the order 10{sup 15} cm < R < 10{sup 17} cm. Most remarkable among those are the rather large values of the emission radius and the electron's Lorentz factor. We find that soft (with peak energy less than 100 keV) but luminous (isotropic luminosity of 1.5 Multiplication-Sign 10{sup 53}) pulses are inefficient. This may explain the lack of strong soft bursts. In cases when most of the energy is carried out by the kinetic energy of the flow, such as in the internal shocks, the synchrotron solution requires that only a small fraction of the electrons are accelerated to relativistic velocities by the shocks. We show that future observations of very high energy photons from GRBs by CTA could possibly determine all parameters of the synchrotron model or rule it out altogether.

  7. Note: Characteristic beam parameter for the line electron gun

    SciTech Connect (OSTI)

    Iqbal, M. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan) [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Islam, G. U. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan)] [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Zhou, Z.; Chi, Y. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2013-11-15T23:59:59.000Z

    We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm{sup 2} at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm{sup 2}), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

  8. Solid angle and surface density as criticality parameters

    SciTech Connect (OSTI)

    Thomas, J.T.

    1980-10-01T23:59:59.000Z

    Two methods often used to establish nuclear criticality safety limits for operations with fissile materials are the surface density and solid angle techniques. The two methods are used as parameters to express experimental and validated calculations of critical configurations. It is demonstrated that each method can represent critical arrangements of subcritical units and that there can be established a one-to-one correspondence between them. The analyses further show that the effect on an array neutron multiplication factor of perturbations to the array can be reliably estimated and that each form of fissile material and unit shape has a specific representation.

  9. gamma+gamma --> pi+pi, K+K : leading term QCD vs handbag model

    E-Print Network [OSTI]

    Victor L. Chernyak

    2006-06-15T23:59:59.000Z

    The "handbag" model was proposed as an alternative, at the present day energies, to the leading term QCD predictions for some hard exclusive processes. The recent precise data from the Belle Collaboration on the large angle cross sections $\\gamma\\gamma --> \\pi\\pi, KK $ allow a check of these two approaches to be performed. It is shown that the handbag model fails to describe the data from Belle, while the leading term QCD predictions are in reasonable agreement with these data

  10. Multi-parameter on-line coal bulk analysis. Technical progress report, March 16, 1995--June 15, 1995

    SciTech Connect (OSTI)

    NONE

    1995-10-01T23:59:59.000Z

    Research continued on multi-parameter on-line coal bulk analysis. The thermal neutron flux distribution in coal and free air for two types of neutron sources was performed. The MCNP code was used to calculate the gamma ray response function and to determine the thermal neutron flux in coal when a lead collimator was used and when paraffin blocks were placed in front of the sample. The identification of chlorine in coal is discussed along with the analysis of the gamma spectra.

  11. Gamma-ray burst spectrum with decaying magnetic field

    SciTech Connect (OSTI)

    Zhao, Xiaohong; Bai, Jinming [Yunnan Observatory, Chinese Academy of Sciences, P.O. Box 110, 650011 Kunming (China); Li, Zhuo [Department of Astronomy and Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Liu, Xuewen; Zhang, Bin-bin; Mészáros, Peter, E-mail: zhaoxh@ynao.ac.cn, E-mail: zhuo.li@pku.edu.cn [Department of Astronomy and Astrophysics and Department of Physics, The Pennsylvania State University, University Park, PA 16802 (United States)

    2014-01-01T23:59:59.000Z

    In the internal shock model for gamma-ray bursts (GRBs), the synchrotron spectrum from the fast cooling electrons in a homogeneous downstream magnetic field (MF) is too soft to produce the low-energy slope of GRB spectra. However, the MF may decay downstream with distance from the shock front. Here we show that the synchrotron spectrum becomes harder if electrons undergo synchrotron and inverse-Compton cooling in a decaying MF. To reconcile this with the typical GRB spectrum with low-energy slope ?F {sub ?}??, the postshock MF decay time must be comparable to the cooling time of the bulk electrons (corresponding to a MF decaying length typically of ?10{sup 5} skin depths); that the inverse-Compton cooling should dominate synchrotron cooling after the MF decay time; and/or that the MF decays with comoving time roughly as B?t {sup –1.5}. An internal shock synchrotron model with a decaying MF can account for the majority of GRBs with low-energy slopes not harder than ?{sup 4/3}.

  12. MAGNETICALLY AND BARYONICALLY DOMINATED PHOTOSPHERIC GAMMA-RAY BURST MODEL FITS TO FERMI-LAT OBSERVATIONS

    SciTech Connect (OSTI)

    Veres, Peter; Meszaros, Peter [Department of Astronomy and Astrophysics, Department of Physics, and Center for Particle and Gravitational Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)] [Department of Astronomy and Astrophysics, Department of Physics, and Center for Particle and Gravitational Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States); Zhang, Bin-Bin, E-mail: veresp@psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)] [Department of Astronomy and Astrophysics, Pennsylvania State University, 525 Davey Lab, University Park, PA 16802 (United States)

    2013-02-10T23:59:59.000Z

    We consider gamma-ray burst models where the radiation is dominated by a photospheric region providing the MeV Band spectrum, and an external shock region responsible for the GeV radiation via inverse Compton scattering. We parameterize the initial dynamics through an acceleration law {Gamma}{proportional_to}r {sup {mu}}, with {mu} between 1/3 and 1 to represent the range between an extreme magnetically dominated and a baryonically dominated regime, depending also on the magnetic field configuration. We compare these models to several bright Fermi-LAT bursts, and show that both the time-integrated and the time-resolved spectra, where available, can be well described by these models. We discuss the parameters which result from these fits, and discuss the relative merits and shortcomings of the two models.

  13. Exclusive Measurements of b -> s gamma Transition Rate and Photon Energy Spectrum

    E-Print Network [OSTI]

    The BABAR Collaboration

    2012-08-30T23:59:59.000Z

    We use 429 fb$^{-1}$ of $e^+e^-$ collision data collected at the $\\Upsilon(4S)$ resonance with the BABAR detector to measure the radiative transition rate of $b\\rightarrow s\\gamma$ with a sum of 38 exclusive final states. The inclusive branching fraction with a minimum photon energy of 1.9 GeV is found to be $\\mathcal{B}(\\bar B \\rightarrow X_{s}\\gamma)=(3.29\\pm 0.19\\pm 0.48)\\times 10^{-4}$ where the first uncertainty is statistical and the second is systematic. We also measure the first and second moments of the photon energy spectrum and extract the best fit values for the heavy-quark parameters, $m_{b}$ and $\\mu_{\\pi}^{2}$, in the kinetic and shape function models.

  14. Magnetic Field and Flavor Effects on the Gamma-Ray Burst Neutrino Flux

    E-Print Network [OSTI]

    Philipp Baerwald; Svenja Hümmer; Walter Winter

    2011-03-04T23:59:59.000Z

    We reanalyze the prompt muon neutrino flux from gamma-ray bursts (GRBs), at the example of the often used reference Waxman-Bahcall GRB flux, in terms of the particle physics involved. We first reproduce this reference flux treating synchrotron energy losses of the secondary pions explicitly. Then we include additional neutrino production modes, the neutrinos from muon decays, the magnetic field effects on all secondary species, and flavor mixing with the current parameter uncertainties. We demonstrate that the combination of these effects modifies the shape of the original Waxman-Bahcall GRB flux significantly, and changes the normalization by a factor of three to four. As a consequence, the gamma-ray burst search strategy of neutrino telescopes may be based on the wrong flux shape, and the constraints derived for the GRB neutrino flux, such as the baryonic loading, may in fact be already much stronger than anticipated.

  15. Identification and elimination of anomalous thermal decay in gamma-ray microcalorimeters

    SciTech Connect (OSTI)

    Horansky, Robert D.; Bennett, Douglas A.; Schmidt, Daniel R.; Ullom, Joel N. [National Institute of Standards and Technology, 325 Broadway MS 686.02, Boulder, Colorado 80305 (United States)] [National Institute of Standards and Technology, 325 Broadway MS 686.02, Boulder, Colorado 80305 (United States); Zink, Barry L. [Department of Physics and Astronomy, University of Denver, Denver, Colorado 80208 (United States)] [Department of Physics and Astronomy, University of Denver, Denver, Colorado 80208 (United States)

    2013-11-18T23:59:59.000Z

    Microcalorimeter detectors rely on superconducting components and cryogenic temperatures to provide over an order-of-magnitude improvement in energy resolution compared to semiconducting sensors. Resolution improvements impact fields from gamma-ray astrophysics to nuclear safeguards. The temporal response of these detectors has been much slower than predicted from the known device parameters. This discrepancy has been attributed to the dynamics of quasiparticles and phonons in the bulk absorber used for absorbing photons. We will show that long-lived states in the glue used for absorber attachment have been the dominant cause of the slow response. Also, we have fabricated microcalorimeters using metal-to-metal diffusion bonding to attach the absorber. These detectors show a significant improvement in their recovery after gamma-ray events and will now enable study of the internal scattering dynamics of the bulk absorber.

  16. MilagroA TeV Observatory for Gamma Ray Bursts

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    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

  17. On The Gamma-Ray Emission From Reticulum II and Other Dwarf Galaxies

    E-Print Network [OSTI]

    Hooper, Dan

    2015-01-01T23:59:59.000Z

    The recent discovery of ten new dwarf galaxy candidates by the Dark Energy Survey (DES) and the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) could increase the Fermi Gamma-Ray Space Telescope's sensitivity to annihilating dark matter particles, potentially enabling a definitive test of the dark matter interpretation of the long-standing Galactic Center gamma-ray excess. In this paper, we compare the previous analyses of Fermi data from the directions of the new dwarf candidates (including the relatively nearby Reticulum II) and perform our own analysis, with the goal of establishing the statistical significance of any gamma-ray signal from these sources. We confirm the presence of an excess from Reticulum II, with a spectral shape that is compatible with the Galactic Center signal. The significance of this emission is greater than that observed from 99.84% of randomly chosen high-latitude blank-sky locations, corresponding to a local detection significance of 3.2 sigma. We improve upon th...

  18. DISCOVERY OF VERY HIGH ENERGY gamma-RAYS FROM THE BLAZAR S5 0716+714

    SciTech Connect (OSTI)

    Anderhub, H.; Biland, A. [ETH Zurich, CH-8093 (Switzerland); Antonelli, L. A. [INAF National Institute for Astrophysics, I-00136 Rome (Italy); Antoranz, P.; Balestra, S.; Barrio, J. A. [Universidad Complutense, E-28040 Madrid (Spain); Backes, M.; Becker, J. K. [Technische Universitaet Dortmund, D-44221 Dortmund (Germany); Baixeras, C. [Universitat Autonoma de Barcelona, E-08193 Bellaterra (Spain); Bastieri, D.; Bock, R. K. [Universita di Padova and INFN, I-35131 Padova (Italy); Becerra Gonzalez, J. [Inst. de AstrofIsica de Canarias, E-38200 La Laguna, Tenerife (Spain); Bednarek, W.; Berger, K. [University of Lodz, PL-90236 Lodz (Poland); Berdyugin, A. [Tuorla Observatory, University of Turku, FI-21500 Piikkioe (Finland); Bernardini, E. [Deutsches Elektronen-Synchrotron (DESY), D-15738 Zeuthen (Germany); Bonnoli, G. [Universita di Siena, and INFN Pisa, I-53100 Siena (Italy); Bordas, P.; Bosch-Ramon, V. [Universitat de Barcelona (ICC/IEEC), E-08028 Barcelona (Spain); Borla Tridon, D., E-mail: elilin@utu.f, E-mail: mazin@ifae.e [Max-Planck-Institut fuer Physik, D-80805 Muenchen (Germany)

    2009-10-20T23:59:59.000Z

    The MAGIC Collaboration reports the detection of the blazar S5 0716+714 (z = 0.31 +- 0.08) in very high energy gamma rays. The observations were performed in 2007 November and in 2008 April, and were triggered by the Kungliga Vetenskapliga Akademi telescope due to the high optical state of the object. An overall significance of the signal accounts to S = 5.8sigma for 13.1 hr of data. Most of the signal (S = 6.9sigma) comes from the 2008 April data sample during a higher optical state of the object suggesting a possible correlation between the Very High Energy gamma-ray and optical emissions. The differential energy spectrum of the 2008 data sample follows a power law with a photon index of GAMMA = 3.45 +- 0.54{sub stat} +- 0.2{sub syst}, and the integral flux above 400 GeV is at the level of (7.5 +- 2.2{sub stat} +- 2.3{sub syst}) x 10{sup -12} cm{sup -2} s{sup -1}, corresponding to a 9% Crab Nebula flux. Modeling of the broadband spectral energy distribution indicates that a structured jet model appears to be more promising in describing the available data than a simple one-zone synchrotron self-Compton model.

  19. Imaging system for cardiac planar imaging using a dedicated dual-head gamma camera

    DOE Patents [OSTI]

    Majewski, Stanislaw (Morgantown, VA); Umeno, Marc M. (Woodinville, WA)

    2011-09-13T23:59:59.000Z

    A cardiac imaging system employing dual gamma imaging heads co-registered with one another to provide two dynamic simultaneous views of the heart sector of a patient torso. A first gamma imaging head is positioned in a first orientation with respect to the heart sector and a second gamma imaging head is positioned in a second orientation with respect to the heart sector. An adjustment arrangement is capable of adjusting the distance between the separate imaging heads and the angle between the heads. With the angle between the imaging heads set to 180 degrees and operating in a range of 140-159 keV and at a rate of up to 500kHz, the imaging heads are co-registered to produce simultaneous dynamic recording of two stereotactic views of the heart. The use of co-registered imaging heads maximizes the uniformity of detection sensitivity of blood flow in and around the heart over the whole heart volume and minimizes radiation absorption effects. A normalization/image fusion technique is implemented pixel-by-corresponding pixel to increase signal for any cardiac region viewed in two images obtained from the two opposed detector heads for the same time bin. The imaging system is capable of producing enhanced first pass studies, bloodpool studies including planar, gated and non-gated EKG studies, planar EKG perfusion studies, and planar hot spot imaging.

  20. Simulation and physical model based gamma-ray burst afterglow analysis

    E-Print Network [OSTI]

    van Eerten, Hendrik

    2015-01-01T23:59:59.000Z

    Advances in our numerical and theoretical understanding of gamma-ray burst afterglow processes allow us to construct models capable of dealing with complex relativistic jet dynamics and non-thermal emission, that can be compared directly to data from instruments such as Swift. Because afterglow blast waves and power law spectra are intrinsically scale-invariant under changes of explosion energy and medium density, templates can be generated from large-scale hydrodynamics simulations. This allows for iterative template-based model fitting using the physical model parameters (quantifying the properties of the burster, emission and observer) directly as fit variables. Here I review how such an approach to afterglow analysis works in practice, paying special attention to the underlying model assumptions, possibilities, caveats and limitations of this type of analysis. Because some model parameters can be degenerate in certain regions of parameter space, or unconstrained if data in a limited number of a bands is a...

  1. Observations of GRB 990123 by the Compton Gamma-Ray Observatory

    E-Print Network [OSTI]

    M. S. Briggs; D. L. Band; R. M. Kippen; R. D. Preece; C. Kouveliotou; J. van Paradijs; G. H. Share; R. J. Murphy; S. M. Matz; A. Connors; C. Winkler; M. L. McConnell; J. M. Ryan; O. R. Williams; C. A. Young; B. Dingus; J. R. Catelli; R. A. M. J. Wijers

    1999-03-16T23:59:59.000Z

    GRB 990123 was the first burst from which simultaneous optical, X-ray and gamma-ray emission was detected; its afterglow has been followed by an extensive set of radio, optical and X-ray observations. We have studied the gamma-ray burst itself as observed by the CGRO detectors. We find that gamma-ray fluxes are not correlated with the simultaneous optical observations, and the gamma-ray spectra cannot be extrapolated simply to the optical fluxes. The burst is well fit by the standard four-parameter GRB function, with the exception that excess emission compared to this function is observed below ~15 keV during some time intervals. The burst is characterized by the typical hard-to-soft and hardness-intensity correlation spectral evolution patterns. The energy of the peak of the nu f_nu spectrum, E_p, reaches an unusually high value during the first intensity spike, 1470 +/- 110 keV, and then falls to \\~300 keV during the tail of the burst. The high-energy spectrum above ~MeV is consistent with a power law with a photon index of about -3. By fluence, GRB 990123 is brighter than all but 0.4% of the GRBs observed with BATSE, clearly placing it on the -3/2 power-law portion of the intensity distribution. However, the redshift measured for the afterglow is inconsistent with the Euclidean interpretation of the -3/2 power-law. Using the redshift value of >= 1.61 and assuming isotropic emission, the gamma-ray fluence exceeds 10E54 ergs.

  2. Specifying authentication using signal events in CSP Siraj A. Shaikh (first and corresponding author)

    E-Print Network [OSTI]

    Doran, Simon J.

    1 Specifying authentication using signal events in CSP Siraj A. Shaikh (first and corresponding in the process algebra Communicating Sequential Processes (CSP) to specify authentication. The purpose, security protocols, CSP, formal specification, Kerberos 1. Introduction Schneider [1] uses Communicating

  3. *Corresponding Author email: sourabh.k.saha@gmail.com Genetic algorithm based optimization and post

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    *Corresponding Author email: sourabh.k.saha@gmail.com Genetic algorithm based optimization and post optimality analysis of multi-pass face milling Sourabh K. Saha* Department of Mechanical Engineering IIT

  4. Quantum McKay correspondence for disc invariants of toric Calabi-Yau 3-orbifolds

    E-Print Network [OSTI]

    Hua-Zhong Ke; Jian Zhou

    2014-10-16T23:59:59.000Z

    We announce a result on quantum McKay correspondence for disc invariants of outer legs in toric Calabi-Yau 3-orbifolds, and illustrate our method in a special example $[\\mathbb C^3 /\\mathbb Z_5 (1, 1, 3)]$.

  5. Andrew Marvell's "Upon Appleton House" and Joseph Mazzeo's poetic of correspondence

    E-Print Network [OSTI]

    Johnson, Eva Jane

    1978-01-01T23:59:59.000Z

    ANDREW MARVELL'S "UPON APPLETON HOUSE" AND JOSEPH MAZZEO'S POETIC OF CORRESPONDENCE A Thesis by EVA JANE JOHNSON Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirement for the degree of MASTER... OF ARTS December 1978 Major Subject: English ANDREW MARVELL'S "UPON APPLETON HOUSE AND JOSEPH MAZZEOsS POETIC OF CORRESPONDENCE A Thesis by EVA JANE JOHNSON Approved as to style and content by: (Chair n of Commrttee Head of Departmen (Member...

  6. Parameter 4 | Open Energy Information

    Open Energy Info (EERE)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual SiteofEvaluatingGroup |JilinLuOpenNorthOlympiaAnalysis) JumpPalcan sPaquin Energy andParameter

  7. Redshifts of the Long Gamma-Ray Bursts

    E-Print Network [OSTI]

    Z. Bagoly; I. Csabai; A. Meszaros; P. Meszaros; I. Horvath; L. G. Balazs; R. Vavrek

    2007-04-06T23:59:59.000Z

    The low energy spectra of some gamma-ray bursts' show excess components beside the power-law dependence. The consequences of such a feature allows to estimate the gamma photometric redshift of the long gamma-ray bursts in the BATSE Catalog. There is good correlation between the measured optical and the estimated gamma photometric redshifts. The estimated redshift values for the long bright gamma-ray bursts are up to z=4, while for the the faint long bursts - which should be up to z=20 - the redshifts cannot be determined unambiguously with this method. The redshift distribution of all the gamma-ray bursts with known optical redshift agrees quite well with the BATSE based gamma photometric redshift distribution.

  8. On the Parameter Estimation of Linear Models of Aggregate Power System Loads

    E-Print Network [OSTI]

    Cańizares, Claudio A.

    1 On the Parameter Estimation of Linear Models of Aggregate Power System Loads Valery Knyazkin-- This paper addressed some theoretical and practical issues relevant to the problem of power system load, and the corresponding results are used to validate a commonly used linear model of aggre- gate power system load

  9. Neutron-driven gamma-ray laser

    DOE Patents [OSTI]

    Bowman, Charles D. (Los Alamos, NM)

    1990-01-01T23:59:59.000Z

    A lasing cylinder emits laser radiation at a gamma-ray wavelength of 0.87 .ANG. when subjected to an intense neutron flux of about 400 eV neutrons. A 250 .ANG. thick layer of Be is provided between two layers of 100 .ANG. thick layer of .sup.57 Co and these layers are supported on a foil substrate. The coated foil is coiled to form the lasing cylinder. Under the neutron flux .sup.57 Co becomes .sup.58 Co by neutron absorption. The .sup.58 Co then decays to .sup.57 Fe by 1.6 MeV proton emission. .sup.57 Fe then transitions by mesne decay to a population inversion for lasing action at 14.4 keV. Recoil from the proton emission separates the .sup.57 Fe from the .sup.57 Co and into the Be, where Mossbauer emission occurs at a gamma-ray wavelength.

  10. Lorentz violation from gamma-ray bursts

    E-Print Network [OSTI]

    Shu Zhang; Bo-Qiang Ma

    2014-06-18T23:59:59.000Z

    The constancy of light speed is a basic assumption in Einstein's special relativity, and consequently the Lorentz invariance is a fundamental symmetry of space-time in modern physics. However, it is speculated that the speed of light becomes energy-dependent due to the Lorentz invariance violation~(LV) in various new physics theories. We analyse the data of the energetic photons from the gamma-ray bursts (GRBs) by the Fermi Gamma-Ray Space Telescope, and find more events to support the energy dependence in the light speed with both linear and quadratic form corrections. We provide two scenarios to understand all the new-released Pass~8 data of bright GRBs by the Fermi-LAT Collaboration, with predictions from such scenarios being testable by future detected GRBs.

  11. Gravitational Radiation from Gamma-Ray Bursts

    E-Print Network [OSTI]

    Tsvi Piran

    2001-02-19T23:59:59.000Z

    Gamma Ray Bursts (GRBs) are the most relativistic objects known so far, involving, on one hand an ultra-relativistic motion with a Lorentz factor $\\Gamma > 100$ and on the other hand an accreting newborn black hole. The two main routes leading to this scenario: binary neutron star mergers and Collapsar - the collapse of a rotating star to a black hole, are classical sources for gravitational radiation. Additionally one expect a specific a gravitational radiation pulse associated with the acceleration of the relativistic ejecta. I consider here the implication of the observed rates of GRBs to the possibility of detection of a gravitational radiation signal associated with a GRB. Unfortunately I find that, with currently planned detectors it is impossible to detect the direct gravitational radiation associated with the GRB. It is also quite unlikely to detect gravitational radiation associated with Collapsars. However, the detection of gravitational radiation from a neutron star merger associated with a GRB is likely.

  12. Compositions containing poly ([gamma]glutamylcysteinyl)glycines

    DOE Patents [OSTI]

    Jackson, P.J.; Delhaize, E.; Robinson, N.J.; Unkefer, C.J.; Furlong, C.

    1992-02-18T23:59:59.000Z

    A method of removing heavy metals from aqueous solution, a composition of matter used in effecting the removal, and the apparatus used in effecting the removal are described. One or more of the polypeptides, poly ([gamma]glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly ([gamma]glutamylcysteinyl)glycines having a particular number of monomer repeat units for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form. 1 figs.

  13. Fissile interrogation using gamma rays from oxygen

    DOE Patents [OSTI]

    Smith, Donald; Micklich, Bradley J.; Fessler, Andreas

    2004-04-20T23:59:59.000Z

    The subject apparatus provides a means to identify the presence of fissionable material or other nuclear material contained within an item to be tested. The system employs a portable accelerator to accelerate and direct protons to a fluorine-compound target. The interaction of the protons with the fluorine-compound target produces gamma rays which are directed at the item to be tested. If the item to be tested contains either a fissionable material or other nuclear material the interaction of the gamma rays with the material contained within the test item with result in the production of neutrons. A system of neutron detectors is positioned to intercept any neutrons generated by the test item. The results from the neutron detectors are analyzed to determine the presence of a fissionable material or other nuclear material.

  14. Compositions containing poly (.gamma.-glutamylcysteinyl)glycines

    DOE Patents [OSTI]

    Jackson, Paul J. (Los Alamos, NM); Delhaize, Emmanuel (Los Alamos, NM); Robinson, Nigel J. (Durham, GB2); Unkefer, Clifford J. (Los Alamos, NM); Furlong, Clement (Seattle, WA)

    1992-01-01T23:59:59.000Z

    A method of removing heavy metals from aqueous solution, a composition of matter used in effecting said removal, and apparatus used in effecting said removal. One or more of the polypeptides, poly (.gamma.-glutamylcysteinyl)glycines, is immobilized on an inert material in particulate form. Upon contact with an aqueous solution containing heavy metals, the polypeptides sequester the metals, removing them from the solution. There is selectivity of poly (.gamma.-glutamylcysteinyl)glycines having a particular number of monomer repeat units for particular metals. The polypeptides are easily regenerated by contact with a small amount of an organic acid, so that they can be used again to remove heavy metals from solution. This also results in the removal of the metals from the column in a concentrated form.

  15. Gamma irradiation in a saturated tuff environment

    SciTech Connect (OSTI)

    Bates, J.K.; Oversby, V.M.

    1984-12-31T23:59:59.000Z

    The influence of gamma irradiation on the reaction of actinide doped SRL 165 and PNL 76-68 glasses in a saturated tuff environment has been studied in a series of tests lasting up to 56 days. The reaction, and subsequent actinide release, of both glasses depends on the dynamic interaction between radiolysis effects which cause the solution pH to become more acidic and glass reaction which drives the pH more basic. The use of large gamma irradiation dose rates to accelerate reactions that would occur in an actual repository radiation field may affect this dynamic balance by unduly influencing the mechanism of the glass-water reaction. Comparisons are made between the present results and data obtained by reacting the same or similar glasses using MCC-1 and NNWSI rock cup procedures. 11 references, 3 figures.

  16. X Ray Precursors in GRBs and SGRs: outer X tails around a Precessing Gamma Jet

    E-Print Network [OSTI]

    Daniele Fargion

    2000-11-27T23:59:59.000Z

    Weak isolated X-ray precursor events before the main Gamma Ray Burst, GRB, and also rare Soft Gamma Repeaters, SGR, events are in disagreement with any Fireball, or Magnetar, scenarios. These models are originated by an unique explosive event leading, by internal-external shock waves, to softer secondary trains following a main gamma signals. Indeed the earliest GRB980519,GRB981226 events as well as the latest and most distant identified one as GRB000131 are showing rare but well identified and distinct X Ray precursor, occurring tens of seconds or even a minute before the main GRB eruption. These weak X precursors bursts correspond to non-negligible energy powers, up to million Supernova ones. They are rare, about (3-6)% of all GRBs, but not unique. Similar huge explosive precursor are in total disagreement with a successive main Fireball GRB outburst. Comparable brief X-ray precursor flashes are found also in rarest and most detailed SGRs events as those observed on 27 and 29 August 1999 from SGR 1900+14. They are inconsistent with a Magnetar Fireball explosion. We interpret them as earlier marginal blazing of outlying X conical Jet tails surrounding a narrower gamma precessing,spinning beamed Jet in blazing mode toward the Earth; later re-crossing and better hitting of the target -the satellite detectors- is source of the main GRB (and SGR) observed structured event. The X Ray precursor existence is an additional remarkable evidence of the Precessing relativistic Jet Nature of both GRBs and SGRs.

  17. Gamma-Ray Bursts: Progress, Problems & Prospects

    E-Print Network [OSTI]

    Bing Zhang; Peter Meszaros

    2003-11-13T23:59:59.000Z

    The cosmological gamma-ray burst (GRB) phenomenon is reviewed. The broad observational facts and empirical phenomenological relations of the GRB prompt emission and afterglow are outlined. A well-tested, successful fireball shock model is introduced in a pedagogical manner. Several important uncertainties in the current understanding of the phenomenon are reviewed, and prospects of how future experiments and extensive observational and theoretical efforts may address these problems are discussed.

  18. Parity Violation in gamma proton Compton Scattering

    E-Print Network [OSTI]

    Paulo F. Bedaque; Martin J. Savage

    1999-10-19T23:59:59.000Z

    A measurement of parity-violating spin-dependent gamma proton Compton scattering will provide a theoretically clean determination of the parity-violating pion-nucleon coupling constant $h_{\\pi NN}^{(1)}$. We calculate the leading parity-violating amplitude arising from one-loop pion graphs in chiral perturbation theory. An asymmetry of ~5 10^{-8} is estimated for Compton scattering of 100 MeV photons.

  19. Gamma-ray Bursts in Wavelet Space

    E-Print Network [OSTI]

    Z. Bagoly; I. Horvath; A. Meszaros; L. G. Balazs

    2005-08-31T23:59:59.000Z

    The gamma-ray burst's lightcurves have been analyzed using a special wavelet transformation. The applied wavelet base is based on a typical Fast Rise-Exponential Decay (FRED) pulse. The shape of the wavelet coefficients' total distribution is determined on the observational frequency grid. Our analysis indicates that the pulses in the long bursts' high energy channel lightcurves are more FRED-like than the lower ones, independently from the actual physical time-scale.

  20. Gamma-Ray Line Observations with RHESSI

    E-Print Network [OSTI]

    David M. Smith

    2004-04-30T23:59:59.000Z

    The Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) has been observing gamma-ray lines from the Sun and the Galaxy since its launch in February 2002. Here I summarize the status of RHESSI observations of solar lines (nuclear de-excitation, neutron capture, and positron annihilation), the lines of $^{26}$Al and $^{60}$Fe from the inner Galaxy, and the search for positron annihilation in novae.

  1. Measuring neutrino oscillation parameters using $\

    SciTech Connect (OSTI)

    Backhouse, Christopher James; /Oxford U.

    2011-02-01T23:59:59.000Z

    MINOS is a long-baseline neutrino oscillation experiment. It consists of two large steel-scintillator tracking calorimeters. The near detector is situated at Fermilab, close to the production point of the NuMI muon-neutrino beam. The far detector is 735 km away, 716m underground in the Soudan mine, Northern Minnesota. The primary purpose of the MINOS experiment is to make precise measurements of the 'atmospheric' neutrino oscillation parameters ({Delta}m{sub atm}{sup 2} and sin{sup 2} 2{theta}{sub atm}). The oscillation signal consists of an energy-dependent deficit of {nu}{sub {mu}} interactions in the far detector. The near detector is used to characterize the properties of the beam before oscillations develop. The two-detector design allows many potential sources of systematic error in the far detector to be mitigated by the near detector observations. This thesis describes the details of the {nu}{sub {mu}}-disappearance analysis, and presents a new technique to estimate the hadronic energy of neutrino interactions. This estimator achieves a significant improvement in the energy resolution of the neutrino spectrum, and in the sensitivity of the neutrino oscillation fit. The systematic uncertainty on the hadronic energy scale was re-evaluated and found to be comparable to that of the energy estimator previously in use. The best-fit oscillation parameters of the {nu}{sub {mu}}-disappearance analysis, incorporating this new estimator were: {Delta}m{sup 2} = 2.32{sub -0.08}{sup +0.12} x 10{sup -3} eV{sup 2}, sin {sup 2} 2{theta} > 0.90 (90% C.L.). A similar analysis, using data from a period of running where the NuMI beam was operated in a configuration producing a predominantly {bar {nu}}{sub {mu}} beam, yielded somewhat different best-fit parameters {Delta}{bar m}{sup 2} = (3.36{sub -0.40}{sup +0.46}(stat.) {+-} 0.06(syst.)) x 10{sup -3}eV{sup 2}, sin{sup 2} 2{bar {theta}} = 0.86{sub -0.12}{sup _0.11}(stat.) {+-} 0.01(syst.). The tension between these results is intriguing, and additional antineutrino data is currently being taken in order to further investigate this apparent discrepancy.

  2. NO CORRELATION BETWEEN HOST GALAXY METALLICITY AND GAMMA-RAY ENERGY RELEASE FOR LONG-DURATION GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Levesque, Emily M.; Kewley, Lisa J. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Soderberg, Alicia M.; Berger, Edo, E-mail: emsque@ifa.hawaii.ed, E-mail: kewley@ifa.hawaii.ed, E-mail: asoderbe@cfa.harvard.ed, E-mail: eberger@cfa.harvard.ed [Smithsonian Astrophysical Observatory, 60 Garden St., MS-20, Cambridge, MA 02138 (United States)

    2010-12-10T23:59:59.000Z

    We compare the redshifts, host galaxy metallicities, and isotropic (E{sub {gamma}},iso) and beaming-corrected (E{sub {gamma}}) gamma-ray energy release of 16 long-duration gamma-ray bursts (LGRBs) at z < 1. From this comparison, we find no statistically significant correlation between host metallicity and redshift, E{sub {gamma}},iso, or E{sub {gamma}}. These results are at odds with previous theoretical and observational predictions of an inverse correlation between gamma-ray energy release and host metallicity, as well as the standard predictions of metallicity-driven wind effects in stellar evolutionary models. We consider the implications that these results have for LGRB progenitor scenarios, and discuss our current understanding of the role that metallicity plays in the production of LGRBs.

  3. A resonance structure in the $\\gamma\\gamma$ invariant mass spectrum in $p$C- and $d$C-interactions

    E-Print Network [OSTI]

    Abraamyan, Kh U; Friesen, A V; Gudima, K K; Kozhin, M A; Lebedev, S A; Nazarenko, M A; Nikitin, S A; Ososkov, G A; Reznikov, S G; Sissakian, A N; Sorin, A S; Toneev, V D

    2008-01-01T23:59:59.000Z

    Along with $\\pi^0$ and $\\eta$ mesons, a resonance structure in the invariant mass spectrum of two photons at $M_{\\gamma\\gamma}= 360 \\pm 7 \\pm 9$ MeV is observed in the reaction $d C\\to\\gamma + \\gamma +X$ at momentum 2.75 GeV/c per nucleon. Estimates of its width and production cross section are $\\Gamma = 49.2 \\pm 18.6$ MeV and $\\sigma_{\\gamma\\gamma}=98\\pm24^{+93}_{-67} {\\rm \\mu b}$, respectively. The collected statistics amount to $2339 \\pm 340$ events of $1.5\\cdot 10^6$ triggered interactions of a total number $\\sim 10^{12}$ of $d$C-interactions. This resonance structure is not observed in $p$C collisions at the beam momentum 5.5 GeV/c. Possible mechanisms of this ABC-like effect are discussed.

  4. GammaCam{trademark} radiation imaging system

    SciTech Connect (OSTI)

    NONE

    1998-02-01T23:59:59.000Z

    GammaCam{trademark}, a gamma-ray imaging system manufactured by AIL System, Inc., would benefit a site that needs to locate radiation sources. It is capable of producing a two-dimensional image of a radiation field superimposed on a black and white visual image. Because the system can be positioned outside the radiologically controlled area, the radiation exposure to personnel is significantly reduced and extensive shielding is not required. This report covers the following topics: technology description; performance; technology applicability and alternatives; cost; regulatory and policy issues; and lessons learned. The demonstration of GammaCam{trademark} in December 1996 was part of the Large-Scale Demonstration Project (LSDP) whose objective is to select and demonstrate potentially beneficial technologies at the Argonne National Laboratory-East (ANL) Chicago Pile-5 Research Reactor (CP-5). The purpose of the LSDP is to demonstrate that by using innovative and improved decontamination and decommissioning (D and D) technologies from various sources, significant benefits can be achieved when compared to baseline D and D technologies.

  5. Prediction of average. beta. and. gamma. energies and probabilities of. beta. -delayed neutron emission in the region of fission products

    SciTech Connect (OSTI)

    Hirsch, M.; Staudt, A.; Klapdor-Kleingrothaus, H.V. (Max-Planck-Inst. fuer Kernphysik, Heidelberg (Germany))

    1992-07-01T23:59:59.000Z

    Mean {beta} and {gamma} energies and probabilities of {beta}-delayed neutron emission (P{sub n}) in the region of fission products are calculated using a proton-neutron quasiparticle random-phase approximation nuclear model. {beta}-decay properties of these nuclides are essential input parameters for decay heat calculations for nuclear reactors. The results are compared with recent measurements. Mean energies and the P{sub n} values of {approximately}150 experimentally unknown short-lived isotopes are predicted.

  6. Search for Prompt Neutrino Emission from Gamma-Ray Bursts with IceCube

    E-Print Network [OSTI]

    Aartsen, M G; Adams, J; Aguilar, J A; Ahlers, M; Ahrens, M; Altmann, D; Anderson, T; Arguelles, C; Arlen, T C; Auffenberg, J; Bai, X; Barwick, S W; Baum, V; Bay, R; Beatty, J J; Tjus, J Becker; Becker, K -H; BenZvi, S; Berghaus, P; Berley, D; Bernardini, E; Bernhard, A; Besson, D Z; Binder, G; Bindig, D; Bissok, M; Blaufuss, E; Blumenthal, J; Boersma, D J; Bohm, C; Bos, F; Bose, D; Böser, S; Botner, O; Brayeur, L; Bretz, H -P; Brown, A M; Buzinsky, N; Casey, J; Casier, M; Cheung, E; Chirkin, D; Christov, A; Christy, B; Clark, K; Classen, L; Clevermann, F; Coenders, S; Cowen, D F; Silva, A H Cruz; Daughhetee, J; Davis, J C; Day, M; de André, J P A M; De Clercq, C; De Ridder, S; Desiati, P; de Vries, K D; de With, M; DeYoung, T; Díaz-Vélez, J C; Dunkman, M; Eagan, R; Eberhardt, B; Ehrhardt, T; Eichmann, B; Eisch, J; Euler, S; Evenson, P A; Fadiran, O; Fazely, A R; Fedynitch, A; Feintzeig, J; Felde, J; Filimonov, K; Finley, C; Fischer-Wasels, T; Flis, S; Frantzen, K; Fuchs, T; Gaisser, T K; Gaior, R; Gallagher, J; Gerhardt, L; Gier, D; Gladstone, L; Glüsenkamp, T; Goldschmidt, A; Golup, G; Gonzalez, J G; Goodman, J A; Góra, D; Grant, D; Gretskov, P; Groh, J C; Groß, A; Ha, C; Haack, C; Ismail, A Haj; Hallen, P; Hallgren, A; Halzen, F; Hanson, K; Hebecker, D; Heereman, D; Heinen, D; Helbing, K; Hellauer, R; Hellwig, D; Hickford, S; Hill, G C; Hoffman, K D; Hoffmann, R; Homeier, A; Hoshina, K; Huang, F; Huelsnitz, W; Hulth, P O; Hultqvist, K; Ishihara, A; Jacobi, E; Jacobsen, J; Japaridze, G S; Jero, K; Jlelati, O; Jurkovic, M; Kaminsky, B; Kappes, A; Karg, T; Karle, A; Kauer, M; Keivani, A; Kelley, J L; Kheirandish, A; Kiryluk, J; Kläs, J; Klein, S R; Köhne, J -H; Kohnen, G; Kolanoski, H; Koob, A; Köpke, L; Kopper, C; Kopper, S; Koskinen, D J; Kowalski, M; Kriesten, A; Krings, K; Kroll, G; Kroll, M; Kunnen, J; Kurahashi, N; Kuwabara, T; Labare, M; Lanfranchi, J L; Larsen, D T; Larson, M J; Lesiak-Bzdak, M; Leuermann, M; Lünemann, J; Madsen, J; Maggi, G; Maruyama, R; Mase, K; Matis, H S; Maunu, R; McNally, F; Meagher, K; Medici, M; Meli, A; Meures, T; Miarecki, S; Middell, E; Middlemas, E; Milke, N; Miller, J; Mohrmann, L; Montaruli, T; Morse, R; Nahnhauer, R; Naumann, U; Niederhausen, H; Nowicki, S C; Nygren, D R; Obertacke, A; Odrowski, S; Olivas, A; Omairat, A; O'Murchadha, A; Palczewski, T; Paul, L; Penek, Ö; Pepper, J A; Heros, C Pérez de los; Pfendner, C; Pieloth, D; Pinat, E; Posselt, J; Price, P B; Przybylski, G T; Pütz, J; Quinnan, M; Rädel, L; Rameez, M; Rawlins, K; Redl, P; Rees, I; Reimann, R; Relich, M; Resconi, E; Rhode, W; Richman, M; Riedel, B; Robertson, S; Rodrigues, J P; Rongen, M; Rott, C; Ruhe, T; Ruzybayev, B; Ryckbosch, D; Saba, S M; Sander, H -G; Sandroos, J; Santander, M; Sarkar, S; Schatto, K; Scheriau, F; Schmidt, T; Schmitz, M; Schoenen, S; Schöneberg, S; Schönwald, A; Schukraft, A; Schulte, L; Schulz, O; Seckel, D; Sestayo, Y; Seunarine, S; Shanidze, R; Smith, M W E; Soldin, D; Spiczak, G M; Spiering, C; Stamatikos, M; Stanev, T; Stanisha, N A; Stasik, A; Stezelberger, T; Stokstad, R G; Stößl, A; Strahler, E A; Ström, R; Strotjohann, N L; Sullivan, G W; Taavola, H; Taboada, I; Tamburro, A; Tepe, A; Ter-Antonyan, S; Terliuk, A; Teši?, G; Tilav, S; Toale, P A; Tobin, M N; Tosi, D; Tselengidou, M; Unger, E; Usner, M; Vallecorsa, S; van Eijndhoven, N; Vandenbroucke, J; van Santen, J; Vanheule, S; Vehring, M; Voge, M; Vraeghe, M; Walck, C; Wallraff, M; Weaver, Ch; Wellons, M; Wendt, C; Westerhoff, S; Whelan, B J; Whitehorn, N; Wichary, C; Wiebe, K; Wiebusch, C H; Williams, D R; Wissing, H; Wolf, M; Wood, T R; Woschnagg, K; Xu, D L; Xu, X W; Xu, Y; Yanez, J P; Yodh, G; Yoshida, S; Zarzhitsky, P; Ziemann, J; Zoll, M

    2014-01-01T23:59:59.000Z

    We present constraints derived from a search of four years of IceCube data for a prompt neutrino flux from gamma-ray bursts (GRBs). A single low-significance neutrino was found in coincidence with one of the 506 observed bursts, consistent with the expectation from atmospheric backgrounds. Although GRBs have been proposed as candidate sources for ultra-high energy cosmic rays, our limits on the neutrino flux disfavor much of the parameter space for the latest models. We also find that no more than $\\sim1\\%$ of the recently observed astrophysical neutrino flux consists of prompt emission from GRBs that are potentially observable by existing satellites.

  7. GAMMA RAYS FROM STAR FORMATION IN CLUSTERS OF GALAXIES

    SciTech Connect (OSTI)

    Storm, Emma M.; Jeltema, Tesla E.; Profumo, Stefano [Department of Physics, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

    2012-08-20T23:59:59.000Z

    Star formation in galaxies is observed to be associated with gamma-ray emission, presumably from non-thermal processes connected to the acceleration of cosmic-ray nuclei and electrons. The detection of gamma rays from starburst galaxies by the Fermi Large Area Telescope (LAT) has allowed the determination of a functional relationship between star formation rate and gamma-ray luminosity. Since star formation is known to scale with total infrared (8-1000 {mu}m) and radio (1.4 GHz) luminosity, the observed infrared and radio emission from a star-forming galaxy can be used to quantitatively infer the galaxy's gamma-ray luminosity. Similarly, star-forming galaxies within galaxy clusters allow us to derive lower limits on the gamma-ray emission from clusters, which have not yet been conclusively detected in gamma rays. In this study, we apply the functional relationships between gamma-ray luminosity and radio and IR luminosities of galaxies derived by the Fermi Collaboration to a sample of the best candidate galaxy clusters for detection in gamma rays in order to place lower limits on the gamma-ray emission associated with star formation in galaxy clusters. We find that several clusters have predicted gamma-ray emission from star formation that are within an order of magnitude of the upper limits derived in Ackermann et al. based on non-detection by Fermi-LAT. Given the current gamma-ray limits, star formation likely plays a significant role in the gamma-ray emission in some clusters, especially those with cool cores. We predict that both Fermi-LAT over the course of its lifetime and the future Cerenkov Telescope Array will be able to detect gamma-ray emission from star-forming galaxies in clusters.

  8. Method for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein

    DOE Patents [OSTI]

    Sinha, Dipen N. (Los Alamos, NM); Anthony, Brian W. (Clearfield, PA)

    1997-01-01T23:59:59.000Z

    A method for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein. A direct correlation between the octane rating of gasoline and the frequency of corresponding acoustic resonances therein has been experimentally observed. Therefore, the octane rating of a gasoline sample can be directly determined through speed of sound measurements instead of by the cumbersome process of quantifying the knocking quality of the gasoline. Various receptacle geometries and construction materials may be employed. Moreover, it is anticipated that the measurements can be performed on flowing samples in pipes, thereby rendering the present method useful in refineries and distilleries.

  9. Method for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein

    DOE Patents [OSTI]

    Sinha, D.N.; Anthony, B.W.

    1997-02-25T23:59:59.000Z

    A method is described for determining the octane rating of gasoline samples by observing corresponding acoustic resonances therein. A direct correlation between the octane rating of gasoline and the frequency of corresponding acoustic resonances therein has been experimentally observed. Therefore, the octane rating of a gasoline sample can be directly determined through speed of sound measurements instead of by the cumbersome process of quantifying the knocking quality of the gasoline. Various receptacle geometries and construction materials may be employed. Moreover, it is anticipated that the measurements can be performed on flowing samples in pipes, thereby rendering the present method useful in refineries and distilleries. 3 figs.

  10. Coal deposit characterization by gamma-gamma density/percent dry ash relationships

    E-Print Network [OSTI]

    Wright, David Scott

    1984-01-01T23:59:59.000Z

    Density/Ash Relationship . APPLICATION OF THE GAMMA-GAMMA DENSITY/PERCENT DRY ASH RELATIONSHIPS The Density/Ash Relationship of a South Texas Lignite Deposit Characterization of a South Texas Lignite Deposit CONCLUSIONS REFERENCES. 52 53 53 53... 58 64 67 6g 80 87 LIST OF TABLES TABLE I Coal Classification by Rank. 2 Common Minerals in Coal. 3 Results of Linear Regression Analyses for a South Texas Lignite Deposit. 4 Variability of Geophysica11y-Derived Percent Dry Ash Values...

  11. Instructions for calibrating gamma detectors using the Canberra-Nuclear Data Genie Gamma Spectroscopy System

    SciTech Connect (OSTI)

    Brunk, J.L.

    1995-09-01T23:59:59.000Z

    A straight forward protocol provides a way to guide the calibration of a gamma detector for a particular geometry and material. Several programs have used the Low Level Gamma Counting Facility of the Health and Ecological Assessment Division of the Lawrence Livermore National Laboratory to count a variety of large environmental samples contained in several unique geometries. The equipment and calibration requirements needed to analyze these types of samples are explained. This document describes the calibration protocol that has been developed and describes how it is used to calibrate the detectors.

  12. What can the L3 $\\gamma\\gamma ll$ events be?

    E-Print Network [OSTI]

    Garisto, R; Garisto, Robert; Ng, John N.

    1993-01-01T23:59:59.000Z

    We consider the 4 $\\gamma\\gamma ll$ ($l=\\mu,\\ e$) events reported by the L3 collaboration, and go through the logical possibilities which could explain the events. If they are not coincidental bremsstrahlung events, we find that the physics which they could point to is extremely limited. One possibility would be to have a new 60 GeV scalar (or pseudoscalar) particle $X^0$ with an off-diagonal coupling to a $Z$ and $Z'$ which is non-perturbative ($\\alpha > 1$), where the $Z'$ couplings to $\

  13. Application of the gamma evaluation method in Gamma Knife film dosimetry

    SciTech Connect (OSTI)

    Park, Jeong-Hoon; Han, Jung Ho; Kim, Chae-Yong; Oh, Chang Wan; Lee, Do-Heui; Suh, Tae-Suk; Gyu Kim, Dong; Chung, Hyun-Tai [Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam 463-707, Korea and Department of Biomedical Engineering, College of Medicine, Catholic University of Korea Seoul 137-701 (Korea, Republic of); Department of Neurosurgery, Seoul National University Bundang Hospital, Seongnam 463-707, Korea and Department of Neurosurgery, College of Medicine, Seoul National University, Seoul 110-799 (Korea, Republic of); Department of Neurosurgery, Asan Medical Center, College of Medicine, University of Ulsan, Seoul 138-736 (Korea, Republic of); Department of Biomedical Engineering and Research Institute of Biomedical Engineering, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Department of Neurosurgery, College of Medicine, Seoul National University, Seoul 110-799 (Korea, Republic of)

    2011-10-15T23:59:59.000Z

    Purpose: Gamma Knife (GK) radiosurgery is a minimally invasive surgical technique for the treatment of intracranial lesions. To minimize neurological deficits, submillimeter accuracy is required during treatment delivery. In this paper, the delivery accuracy of GK radiosurgery was assessed with the gamma evaluation method using planning dose distribution and film measurement data. Methods: Single 4, 8, and 16 mm and composite shot plans were developed for evaluation using the GK Perfexion (PFX) treatment planning system (TPS). The planning dose distributions were exported as digital image communications in medicine - radiation therapy (DICOM RT) files using a new function of GK TPS. A maximum dose of 8 Gy was prescribed for four test plans. Irradiation was performed onto a spherical solid water phantom using Gafchromic EBT2 films in the axial and coronal planes. The exposed films were converted to absolute dose based on a 4th-order polynomial calibration curve determined using ten calibration films. The film measurement results and planning dose distributions were registered for further analysis in the same Leksell coordinate using in-house software. The gamma evaluation method was applied to two dose distributions with varying spatial tolerance (0.3-2.0 mm) and dosimetric tolerance (0.3-2.0%), to verify the accuracy of GK radiosurgery. The result of gamma evaluation was assessed using pass rate, dose gamma index histogram (DGH), and dose pass rate histogram (DPH). Results: The 20, 50, and 80% isodose lines found in film measurements were in close agreement with the planning isodose lines, for all dose levels. The comparison of diagonal line profiles across the axial plane yielded similar results. The gamma evaluation method resulted in high pass rates of >95% within the 50% isodose line for 0.5 mm/0.5% tolerance criteria, in both the axial and coronal planes. They satisfied 1.0 mm/1.0% criteria within the 20% isodose line. Our DGH and DPH also showed that low isodose lines exhibited inferior gamma indexes and pass rates compared with higher isodose lines. Conclusions: The gamma evaluation method was applicable to GK radiosurgery. For all test plans, planning dose distribution and film measurement met the tolerance criteria of 0.5 mm/0.5% within the 50% isodose line which are used for marginal dose prescription.

  14. Neutrino Astronomy: Physics Goals, Detector Parameters

    E-Print Network [OSTI]

    T. K. Gaisser

    1997-07-25T23:59:59.000Z

    This is a review of high energy neutrino astronomy that might be done with a kilometer-scale detector. The emphasis is on diffuse neutrinos of extragalactic origin and their relation to possible sources of the highest energy cosmic rays, such as active galaxies, cosmological gamma-ray burst sources and topological defects.

  15. Energy Injection in Gamma-ray Burst Afterglows

    E-Print Network [OSTI]

    Laskar, Tanmoy; Margutti, Raffaella; Perley, Daniel; Zauderer, B Ashley; Sari, Re'em; Fong, Wen-fai

    2015-01-01T23:59:59.000Z

    We present multi-wavelength observations and modeling of Gamma-ray Bursts (GRBs) that exhibit a simultaneous re-brightening in their X-ray and optical light curves, and are also detected at radio wavelengths. We show that the re-brightening episodes can be modeled by injection of energy into the blastwave and that in all cases the energy injection rate falls within the theoretical bounds expected for a distribution of energy with ejecta Lorentz factor. Our measured values of the circumburst density, jet opening angle, and beaming corrected kinetic energy are consistent with the distribution of these parameters for long-duration GRBs at both z~1 and z>6, suggesting that the jet launching mechanism and environment of these events are similar to that of GRBs that do not have bumps in their light curves. However, events exhibiting re-brightening episodes have lower radiative efficiencies than average, suggesting that a majority of the kinetic energy of the outflow is carried by slow-moving ejecta, which is furthe...

  16. Application of Artificial Neural Network to Search for Gravitational-Wave Signals Associated with Short Gamma-Ray Bursts

    E-Print Network [OSTI]

    Kim, Kyungmin; Hodge, Kari A; Kim, Young-Min; Lee, Chang-Hwan; Lee, Hyun Kyu; Oh, John J; Oh, Sang Hoon; Son, Edwin J

    2014-01-01T23:59:59.000Z

    We apply a machine learning algorithm, the artificial neural network, to the search for gravitational-wave signals associated with short gamma-ray bursts. The multi-dimensional samples consisting of data corresponding to the statistical and physical quantities from the coherent search pipeline are fed into the artificial neural network to distinguish simulated gravitational-wave signals from background noise artifacts. Our result shows that the data classification efficiency at a fixed false alarm probability is improved by the artificial neural network in comparison to the conventional detection statistic. Therefore, this algorithm increases the distance at which a gravitational-wave signal could be observed in coincidence with a gamma-ray burst. In order to demonstrate the performance, we also evaluate a few seconds of gravitational-wave data segment using the trained networks and obtain the false alarm probability. We suggest that the artificial neural network can be a complementary method to the conventio...

  17. DISCOVERY OF TeV GAMMA-RAY EMISSION TOWARD SUPERNOVA REMNANT SNR G78.2+2.1

    SciTech Connect (OSTI)

    Aliu, E. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Archambault, S. [Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada); Arlen, T.; Aune, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Bird, R.; Cannon, A.; Collins-Hughes, E. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Bouvier, A. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Bradbury, S. M. [School of Physics and Astronomy, University of Leeds, Leeds, LS2 9JT (United Kingdom); Byrum, K. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Cesarini, A.; Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Cui, W. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Duke, C., E-mail: amandajw@iastate.edu [Department of Physics, Grinnell College, Grinnell, IA 50112-1690 (United States); and others

    2013-06-20T23:59:59.000Z

    We report the discovery of an unidentified, extended source of very-high-energy gamma-ray emission, VER J2019+407, within the radio shell of the supernova remnant SNR G78.2+2.1, using 21.4 hr of data taken by the VERITAS gamma-ray observatory in 2009. These data confirm the preliminary indications of gamma-ray emission previously seen in a two-year (2007-2009) blind survey of the Cygnus region by VERITAS. VER J2019+407, which is detected at a post-trials significance of 7.5 standard deviations in the 2009 data, is localized to the northwestern rim of the remnant in a region of enhanced radio and X-ray emission. It has an intrinsic extent of 0.23 Degree-Sign .23 {+-} 0. Degree-Sign 03{sub stat-0 Degree-Sign .02sys}{sup +0 Degree-Sign .04} and its spectrum is well-characterized by a differential power law (dN/dE = N{sub 0} Multiplication-Sign (E/TeV){sup -{Gamma}}) with a photon index of {Gamma} = 2.37 {+-} 0.14{sub stat} {+-} 0.20{sub sys} and a flux normalization of N{sub 0} = 1.5 {+-} 0.2{sub stat} {+-} 0.4{sub sys} Multiplication-Sign 10{sup -12} photon TeV{sup -1} cm{sup -2} s{sup -1}. This yields an integral flux of 5.2 {+-} 0.8{sub stat} {+-} 1.4{sub sys} Multiplication-Sign 10{sup -12} photon cm{sup -2} s{sup -1} above 320 GeV, corresponding to 3.7% of the Crab Nebula flux. We consider the relationship of the TeV gamma-ray emission with the GeV gamma-ray emission seen from SNR G78.2+2.1 as well as that seen from a nearby cocoon of freshly accelerated cosmic rays. Multiple scenarios are considered as possible origins for the TeV gamma-ray emission, including hadronic particle acceleration at the SNR shock.

  18. Considerations on ODR beam-size monitoring for gamma = 1000 beams

    SciTech Connect (OSTI)

    Lumpkin, A.H.; /Fermilab; Yao, C.-Y.; /Argonne; Chiadroni, E.; Castellano, M.; /LNF, Dafne Light; Cianchi, A.; /Rome U.,Tor Vergata

    2008-04-01T23:59:59.000Z

    We discuss the feasibility of monitoring the beam size of {gamma} = 1000 beams with 3000 times more charge in a video frame time and with a more sensitive 12- to 16-bit camera than were used in the previous electron beam studies at 7 GeV at the Advanced Photon Source. Such a beam would be generated at Fermilab in a new facility in the coming years. Numerical integrations of our base model show beam size sensitivity for {+-} 20% level changes at 200- and 400-{micro}m base beam sizes. We also evaluated impact parameters of 5 {sigma}{sub y} and 12 {sigma}{sub y} for both 800-nm and 10-{micro}m observation wavelengths. The latter examples are related to a proposal to apply the technique to an {approx}0.98 TeV proton beam, and this study shows there are trades on photon intensity and beam size sensitivity to be considered at such gammas. In addition, we report on first results at {gamma} = 1800 on a superconducting rf linac.

  19. A Combined Neutron and Gamma-Ray Multiplicity Counter Based on Liquid Scintillation Detectors

    SciTech Connect (OSTI)

    Andreas Enqvist; Marek Flaska; Jennifer Dolan; David L. Chichester; Sara A. Pozzi

    2011-10-01T23:59:59.000Z

    Multiplicity counters for neutron assay have been extensively used in materials control and accountability for nonproliferation and nuclear safeguards. Typically, neutron coincidence counters are utilized in these fields. In this work, we present a measurement system that makes use not only of neutron (n) multiplicity counting but also of gamma-ray (g) multiplicity counting and the combined higher-order multiples containing both neutrons and gamma rays. The benefit of this approach is in using both particle types available from the sample, leading to a reduction in measurement times needed when using more measurables. We present measurement results of n, g, nn, ng, gg, nnn, nng, ngg, and ggg multiples emitted by Mixed-Oxide (MOX) samples measured at Idaho National Laboratory (INL). The MOX measurement is compared to initial validation of the detection system done using a 252Cf source. The dual radiation measuring system proposed here uses extra measurables to improve the statistics when compared to a neutron-only system and allows for extended analysis and interpretation of sample parameters. New challenges such as the effect of very high intrinsic gamma-ray sources in the case of MOX samples is discussed. Successful measurements of multiples rates can be performed also when using high-Z shielding.

  20. Gamma-ray burst interaction with dense interstellar medium

    E-Print Network [OSTI]

    Maxim Barkov; Gennady Bisnovatyi-Kogan

    2004-10-07T23:59:59.000Z

    Interaction of cosmological gamma ray burst radiation with the dense interstellar medium of host galaxy is considered. Gas dynamical motion of interstellar medium driven by gamma ray burst is investigated in 2D approximation for different initial density distributions of host galaxy matter and different total energy of gamma ray burst. The maximum velocity of motion of interstellar medium is $1.8\\cdot10^4$ km/s. Light curves of gamma ray burst afterglow are calculated for set of non homogeneous density, distribution gamma ray burst total energy, and different viewing angles. Spectra of gamma ray burst afterglow are modeled taking into account conversion of hard photons (soft X-ray, hard UV) to soft UV and optics photons.

  1. X-Ray Observations of Gamma-Ray Burst Afterglows

    E-Print Network [OSTI]

    Filippo Frontera

    2004-06-25T23:59:59.000Z

    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.

  2. Measurements of the B to Xs gamma Branching Fraction and Spectral Shape from a Sum of Exclusive Final States

    SciTech Connect (OSTI)

    Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Tisserand, V.; Zghiche, A.; /Annecy, LAPP; Grauges, E.; /Barcelona, IFAE; Palano, A.; Pappagallo, M.; Pompili, A.; /Bari U. /INFN, Bari; Chen, J.C.; Qi, N.D.; Rong, G.; Wang, P.; Zhu, Y.S.; /Beijing, Inst. High Energy Phys.; Eigen, G.; Ofte, I.; Stugu, B. /Bergen U. /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /Bristol U. /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UCLA /UC, Riverside /UC, San

    2005-08-26T23:59:59.000Z

    Using 88.9 million B{bar B} events collected by the BABAR detector at the {Upsilon}(4S), they measure the branching fraction for the radiative penguin process B {yields} X{sub s}{gamma} from the sum of 38 exclusive final states. The inclusive branching fraction above a minimum photon energy E{sub {gamma}} > 1.9 GeV is {Beta}(b {yields} s{gamma}) = (3.27 {+-} 0.18(stat.){sub -0.40}{sup +0.55}(syst.){sub -0.09}{sup +0.04}(theory)) x 10{sup -4}. They also measure the isospin asymmetry between B{sup -} {yields} X{sub s{bar u}}{gamma} and {bar B}{sup 0} {yields} X{sub sd}{gamma} to be {Delta}{sub 0-} = -0.006 {+-} 0.058(stat.) {+-} 0.009(syst.) {+-} 0.024({bar B}{sup 0}/B{sup -}). The photon energy spectrum is measured in the B rest frame, from which moments are derived for different values of the minimum photon energy. They present fits to the photon spectrum and moments which give the heavy-quark parameters m{sub b} and {mu}{sub {pi}}{sup 2}. The fitted parameters are consistent with those obtained from semileptonic B {yields} X{sub c}{ell}{nu} decays, and are useful inputs for the extraction of |V{sub ub}| from measurements of semileptonic B {yields} X{sub u}{ell}{nu} decays.

  3. Gamma-ray Bursts as Probes of Galaxy Evolution

    E-Print Network [OSTI]

    ?umer, Slobodan

    Gamma-ray Bursts as Probes of Galaxy Evolution Daniele Malesani, Dark Cosmology Centre and the X of the "Universe") #12;What is a gamma-ray burst? Brief (ms - min) and intense (~10-7 erg cm­2 s­1 ) burst of soft to ongoing star formation "Naked-eye" GRB 080319B GRBs explode within star-forming galaxies Gamma-ray bursts

  4. Gamma Ray Bursts, Neutron Star Quakes, and the Casimir Effect

    E-Print Network [OSTI]

    C. Carlson; T. Goldman; J. Perez-Mercader

    1994-11-25T23:59:59.000Z

    We propose that the dynamic Casimir effect is a mechanism that converts the energy of neutron starquakes into $\\gamma$--rays. This mechanism efficiently produces photons from electromagnetic Casimir energy released by the rapid motion of a dielectric medium into a vacuum. Estimates based on the cutoff energy of the gamma ray bursts and the volume involved in a starquake indicate that the total gamma ray energy emission is consonant with observational requirements.

  5. Plastic Gamma Sensors: An Application in Detection of Radioisotopes

    SciTech Connect (OSTI)

    S. Mukhopadhyay

    2003-06-01T23:59:59.000Z

    A brief survey of plastic scintillators for various radiation measurement applications is presented here. The utility of plastic scintillators for practical applications such as gamma radiation monitoring, real-time radioisotope detection and screening is evaluated in laboratory and field measurements. This study also reports results of Monte Carlo-type predictive responses of common plastic scintillators in gamma and neutron radiation fields. Small-size plastic detectors are evaluated for static and dynamic gamma-ray detection sensitivity of selected radiation sources.

  6. Nuclear Criticality as a Contributor to Gamma Ray Burst Events

    E-Print Network [OSTI]

    Robert Bruce Hayes

    2013-01-15T23:59:59.000Z

    Most gamma ray bursts are able to be explained using supernovae related phenomenon. Some measured results still lack compelling explanations and a contributory cause from nuclear criticality is proposed. This is shown to have general properties consistent with various known gamma ray burst properties. The galactic origin of fast rise exponential decay gamma ray bursts is considered a strong candidate for these types of events.

  7. Notes and Correspondence Are Tropical Cyclones Less Effectively Formed by Easterly Waves in the

    E-Print Network [OSTI]

    Chen, Tsing-Chang "Mike"

    tropical cyclones in the western North Pacific. By carefully separating easterly waves from the lowerNotes and Correspondence Are Tropical Cyclones Less Effectively Formed by Easterly Waves@iastate.edu #12;1 Abstract It has been observed that the percentage of tropical cyclones originating from easterly

  8. Impact of Private Tutoring on Learning Levels: Evidence from India Ambrish Dongre (Corresponding Author),

    E-Print Network [OSTI]

    Bandyopadhyay, Antar

    Author), Fellow, Centre for Policy Research, Dharam Marg, Chanakyapuri, New Delhi ­ 110 021, India. Email, Centre for Policy Research, Dharam Marg, Chanakyapuri, New Delhi ­ 110 021, India. Email: vibhutewary1 Impact of Private Tutoring on Learning Levels: Evidence from India Ambrish Dongre (Corresponding

  9. NOTES AND CORRESPONDENCE An Analytic Longwave Radiation Formula for Liquid Layer Clouds

    E-Print Network [OSTI]

    NOTES AND CORRESPONDENCE An Analytic Longwave Radiation Formula for Liquid Layer Clouds VINCENT E of boundary layer clouds have used a convenient but idealized longwave radiation formula for clouds in their large-eddy simulations (LESs). Under what conditions is this formula justified? Can it be extended

  10. Ozone database in support of CMIP5 simulations: results and corresponding

    E-Print Network [OSTI]

    Wirosoetisno, Djoko

    Ozone database in support of CMIP5 simulations: results and corresponding radiative forcing 1234567 Attribution 3.0 License. Atmospheric Chemistry and Physics Ozone database in support of CMIP5 simulations 2011 Abstract. A continuous tropospheric and stratospheric ver- tically resolved ozone time series

  11. NOTES AND CORRESPONDENCE Dissipative Losses in Nonlinear Internal Waves Propagating across the

    E-Print Network [OSTI]

    Smyth, William David

    NOTES AND CORRESPONDENCE Dissipative Losses in Nonlinear Internal Waves Propagating across, however, dissipative ef- fects are negligible and the wave may be considered freely propagating. We of an individual wave propagating onto the con- tinental shelf (Fig. 1). In particular, we follow the lead- ing

  12. LASER TRANSFER DOPING USING AMORPHOUS SILICON Rafel Ferr (Correspondence author)1

    E-Print Network [OSTI]

    LASER TRANSFER DOPING USING AMORPHOUS SILICON Rafel Ferré (Correspondence author)1 , Ralf Gogolin1@isfh.de ABSTRACT: We demonstrate and characterize "Laser Transfer Doping" (LTD) for producing locally doped regions. For this purpose we use nanosecond pulsed laser for transferring phosphorus doped amorphous silicon from a carrier

  13. N-fusion plan divides backers Toshiro Ikemura / Yomiuri Shimbun Correspondent

    E-Print Network [OSTI]

    to make ITER a showpiece of international cooperation. Japan has played a leading role in nuclear fusionN-fusion plan divides backers Toshiro Ikemura / Yomiuri Shimbun Correspondent Japan and France, a technology proponents believe is the future of energy generation. France appears determined to prevail over

  14. Holographic duality (or the AdS/CFT correspondence), originally proposed by

    E-Print Network [OSTI]

    holographic dual of quantum chromodynamics is not yet known), are particularly valuable because this problem in this exciting field. It attracted an unusually diverse group, including general relativity experts, high energy correspond to heating up the boundary quantum matter. This is closely related to Hawking's famous discovery

  15. corresponding author: jean-luc.maurice@polytechnique.edu DEVELOPING LOW-COST GRAPHENE DEVICES

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    corresponding author: jean-luc.maurice@polytechnique.edu DEVELOPING LOW-COST GRAPHENE DEVICES C. S In spite of numerous efforts for developing the applications of graphene, it remains difficult to put-area (industrial) graphene includes in its structure and on its surfaces a significant density of defects that make

  16. IIR Workshop on Refrigerant Charge Reduction in Refrigerating Systems Corresponding author: P. Leblay

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    3rd IIR Workshop on Refrigerant Charge Reduction in Refrigerating Systems Corresponding author: P on the refrigerant side and louver fins on the air side. The flat tubes are grouped within a header, to use the heat diameter implies a refrigerant distribution much more penalizing for these exchangers than for round tube

  17. EFFECTIVENESS OF LEAD-LAG PHASING ON PROGRESSION BANDWIDTH Zong Tian (Corresponding Author)

    E-Print Network [OSTI]

    Tian, Zong Z.

    EFFECTIVENESS OF LEAD-LAG PHASING ON PROGRESSION BANDWIDTH Zong Tian (Corresponding Author) Varun of using lead-lag phasing, and 2) the effect of number of signals on progression bandwidth. A computer that lead-lag phasing had a significant advantage over the leading left-turn and lagging left-turn phasing

  18. UCSB helps develop massive coastal radar network GARRY WORMSER, NEWS-PRESS CORRESPONDENT

    E-Print Network [OSTI]

    California at Santa Barbara, University of

    UCSB helps develop massive coastal radar network GARRY WORMSER, NEWS-PRESS CORRESPONDENT June 12, is experiencing a green resurgence in a massive mapping network of computerized systems that can save the lives., to Tijuana, Mexico. UCSB and other member institutions of the Southern California Coastal Ocean Observing

  19. Methods in comparative genomics: genome correspondence, gene identification and motif discovery

    E-Print Network [OSTI]

    Kellis, Manolis

    1 Methods in comparative genomics: genome correspondence, gene identification and motif discovery@mit.edu, nickp@genome.wi.mit.edu, bwb@genome.wi.mit.edu, bab@mit.edu, lander@wi.mit.edu (1) MIT/Whitehead Institute Center for Genome Research, 320 Charles St., Cambridge MA 02139 (2) MIT Computer Science

  20. Corresponding Author: Biotactic@hotmail.com Mobility of Riverine Smallmouth Bass Related to Tournament

    E-Print Network [OSTI]

    Cooke, Steven J.

    of tournament fish originate. There are no available data on dis- persal of bass from tournament release areas1 1 Corresponding Author: Biotactic@hotmail.com Mobility of Riverine Smallmouth Bass Related.--Mobility of tournament-caught and released smallmouth bass Micropterus dolomieu was monitored in the Grand River, Ontario

  1. Corresponding author: TaeWon Seo E-mail: taewon.seo1@gmail.com

    E-Print Network [OSTI]

    Kim, Jongwon

    Corresponding author: TaeWon Seo E-mail: taewon.seo1@gmail.com Journal of Bionic Engineering 6 , TaeWon Seo2 , Byungwook Kim1 , Dongsu Jeon1 , Kyu-Jin Cho1 , Jongwon Kim1 1. School of Mechanical

  2. * Corresponding author. Solar Energy Materials & Solar Cells 58 (1999) 209}218

    E-Print Network [OSTI]

    Romeo, Alessandro

    * Corresponding author. Solar Energy Materials & Solar Cells 58 (1999) 209}218 A highly e$cient and stable CdTe/CdS thin "lm solar cell N. Romeo, A. Bosio, R. Tedeschi*, A. Romeo, V. Canevari Dipartimento$cient and stable CdTe/CdS thin "lm solar cells. Our cells are prepared in three subsequent phases. Firstly, we

  3. NATURE|Vol 437|20 October 2005 CORRESPONDENCE Don'tunderestimatethe

    E-Print Network [OSTI]

    Mousseau, Timothy A.

    NATURE|Vol 437|20 October 2005 CORRESPONDENCE 1089 Don'tunderestimatethe deathratefromChernobyl SIR -- Your News story "Chernobyl: poverty and stress pose `bigger threat' than radiation" (Nature 437, 181; 2005) suggests that the health and environmental effects of the Chernobyl accident were not as great

  4. Organizational Processes for B2B Services IMC Data Quality Debra Zahay (Corresponding Author)

    E-Print Network [OSTI]

    Ahmad, Sajjad

    1 Organizational Processes for B2B Services IMC Data Quality Debra Zahay (Corresponding Author;2 Organizational Processes for B2B Services IMC Data Quality Structured Abstract: Purpose: The objective of our, and to do so, we develop and test an organizational data quality enhancement model. Design

  5. 368 IEEE TRANSACTIONS ON FUZZY SYSTEMS, VOL. 7, NO. 3, JUNE 1999 Correspondence

    E-Print Network [OSTI]

    Kuncheva, Ludmila I.

    to make and publish comparisons of models and their performance on common data sets and the pattern368 IEEE TRANSACTIONS ON FUZZY SYSTEMS, VOL. 7, NO. 3, JUNE 1999 Correspondence Will the Real Iris models. On the other hand, there are certain risks too. Sometimes conclusions that are legitimate

  6. COLLECTlOWo OF CORRESPONDENCE AND : L-LWIJSCRIPT Shelved off-site

    E-Print Network [OSTI]

    Salzman, Daniel

    COLLECTlOWo OF CORRESPONDENCE AND : L-LWIJSCRIPT Shelved off-site N.,n3 OF COLLECTION i Robert organized; CCWDITION: (give number of vols«, boxes, or shelves) Bound: Boxad: S5 Stored: LOCATION: (Library Marxism Radio "12 Case Press Comment Shelved off-sfte' Box 6 Minor, B-cbert: "To tell the truth" o

  7. NOTES AND CORRESPONDENCE Surface Melting over Ice Shelves and Ice Sheets as Assessed from Modeled

    E-Print Network [OSTI]

    Meissner, Katrin Juliane

    NOTES AND CORRESPONDENCE Surface Melting over Ice Shelves and Ice Sheets as Assessed from Modeled of ice shelves and their progenitor ice sheets. To explore the magnitude of surface melt occurring over modern ice shelves and ice sheets in a climate scenario forced by anthropogenic emissions of carbon

  8. 28 June 03 July 2009, Krakow, Poland * Corresponding author: S.Okochi

    E-Print Network [OSTI]

    Kasagi, Nobuhide

    ExHFT-7 28 June ­ 03 July 2009, Krakow, Poland * Corresponding author: S.Okochi Phone:+81 undesirable vibration, noise and energy losses [1]. To achieve such flow controls, many actuators have been on Experimental Heat Transfer, Fluid Mechanics and Thermodynamics 28 June ­ 03 July 2009, Krakow, Poland

  9. IEEE TRANSACTIONS ON SIGNAL PROCESSING, VOL. 54, NO. 12, DECEMBER 2006 4817 Correspondence

    E-Print Network [OSTI]

    Scharf, Louis

    Canonical Coordinates are the Right Coordinates for Low-Rank Gauss­Gauss Detection and Estimation Ali that Gauss-Gauss detectors and estimators share canonical coordinates in the case where the under- lying in this correspondence is to show that canonical coordinates are also optimal for building the low-rank Gauss­Gauss

  10. A Correspondence between Phenomenological and IBM-1 Models of Even Isotopes of Yb

    E-Print Network [OSTI]

    Abdurahim Okhunov; Fadhil I. Sharrad; Anwer A. Al-Sammarea

    2014-08-01T23:59:59.000Z

    This paper studies the nonterminal complexity of weakly conditional grammars, and it proves that every recursively enumerable language can be generated by a weak conditional grammar with no more than \\textit{seven} nonterminals. Moreover, it is shown that the number of nonterminals in weakly conditional grammars without erasing rules leads to an infinite hierarchy of families of languages generated by weakly conditional grammars. Energy levels and the reduced probability of $E2$-- transitions for Ytterbium isotopes with proton number $Z=70$ and neutron numbers between 100 and 106 have been calculated through phenomenological ($PhM$) and interacting boson ($IBM-1$) models. The predicted low-lying levels (energies, spins and parities) and the reduced probability for $E2$-- transitions results are reasonably consistent with the available experimental data. The predicted low-lying levels ($gr$--, $\\beta_1$-- and $\\gamma_1$-- band) by produced in the $PhM$ are in good agreement with the experimental data comparison with those by $IBM-1$ for all nuclei of interest. In addition, the phenomenological model was successful in predicted the $\\beta_2$--, $\\beta_3$--, $\\beta_4$--, $\\gamma_2$-- and $1^+$-- band while it was a failure with $IBM-1$. Also, the $3^+$-- band is predicted by the $IBM-1$ model for $^{172}Yb$ and $^{174}Yb$ nuclei. All calculations are compared with the available experimental data.

  11. Possible Stimulated Emission of Entangled Rhodium Mossbauer Gammas

    E-Print Network [OSTI]

    Yao Cheng; Zhongming Wang

    2006-11-02T23:59:59.000Z

    Observation of possible stimulated emission of Mossbauer gamma is reported by liquid-nitrogen quenching of rhodium sample from room temperature to 77K in the time-resolved Mossbauer spectroscopy. Recently, we have demonstrated the anomalous emission of three entangled gammas of the E3 Mossbauer transition generated by bremsstrahlung irradiation. In this work, we further report the high-speed decay of excited state. We conjecture that cooling shrinkage, gravitational redshift and crystal lattice collimate entangled gammas in a linear cavity. This opens up a new approach towards gamma lasing, if the stimulated emission occurs at this obtained low excitation density.

  12. Possible Stimulated Emission of Entangled Rhodium Mossbauer Gammas

    E-Print Network [OSTI]

    Cheng, Y; Cheng, Yao; Wang, Zhongming

    2006-01-01T23:59:59.000Z

    Observation of possible stimulated emission of Mossbauer gamma is reported by liquid-nitrogen quenching of rhodium sample from room temperature to 77K in the time-resolved Mossbauer spectroscopy. Recently, we have demonstrated the anomalous emission of three entangled gammas of the E3 Mossbauer transition generated by bremsstrahlung irradiation. In this work, we further report the high-speed decay of excited state. We conjecture that cooling shrinkage, gravitational redshift and crystal lattice collimate entangled gammas in a linear cavity. This opens up a new approach towards gamma lasing, if the stimulated emission occurs at this obtained low excitation density.

  13. attenuates gamma radiation: Topics by E-print Network

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

    Galactic interstellar radiation field, we calculate the attenuation of the very high energy gamma rays from the Galactic sources. The infra-red radiation background near the...

  14. atmospheric gamma rays: Topics by E-print Network

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

    Cherenkov telescope for gamma-ray astronomy. STACEE uses the large mirror area of a solar heliostat facility to achieve a low energy threshold. A prototype experiment which...

  15. accompanying gamma radiation: Topics by E-print Network

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

    Summary: We discuss the possible simultaneously UVoptical emission accompanying Gamma-ray bursts (GRBs). We show that as long as the intrinsic spectrum of GRB can extend to ...

  16. actinium gamma spectra: Topics by E-print Network

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

    We discuss here constraints on the particle acceleration models from the observed gamma-ray bursts spectra. The standard synchrotron shock model assumes that some fraction of...

  17. Virtual Gamma Ray Radiation Sources through Neutron Radiative Capture

    SciTech Connect (OSTI)

    Scott Wilde, Raymond Keegan

    2008-07-01T23:59:59.000Z

    The countrate response of a gamma spectrometry system from a neutron radiation source behind a plane of moderating material doped with a nuclide of a large radiative neutron capture cross-section exhibits a countrate response analogous to a gamma radiation source at the same position from the detector. Using a planar, surface area of the neutron moderating material exposed to the neutron radiation produces a larger area under the prompt gamma ray peak in the detector than a smaller area of dimensions relative to the active volume of the gamma detection system.

  18. Dirac fields, torsion and Barbero-Immirzi parameter in cosmology

    SciTech Connect (OSTI)

    Berredo-Peixoto, G. de; Shapiro, I.L.; Souza, C.A. de [Departamento de Física, ICE, Universidade Federal de Juiz de Fora, Campus Universitário, Juiz de Fora, 36036-330, Minas Gerais (Brazil); Freidel, L., E-mail: guilherme@fisica.ufjf.br, E-mail: lfreidel@perimeterinstitute.ca, E-mail: shapiro@fisica.ufjf.br, E-mail: abrahaocleber@gmail.com [Perimeter Institute for Theoretical Physics, 31 Caroline St. N, N2L 2Y5, Waterloo ON (Canada)

    2012-06-01T23:59:59.000Z

    We consider cosmological solution for Einstein gravity with massive fermions with a four-fermion coupling, which emerges from the Holst action and is related to the Barbero-Immirzi (BI) parameter. This gravitational action is an important object of investigation in a non-perturbative formalism of quantum gravity. We study the equation of motion for the Dirac field within the standard Friedman-Robertson-Walker (FRW) metric. Finally, we show the theory with BI parameter and minimally coupling Dirac field, in the zero mass limit, is equivalent to an additional term which looks like a perfect fluid with the equation of state p = w?, with w = 1 which is independent of the BI parameter. The existence of mass imposes a variable w, which creates either an inflationary phase with w = ?1, or assumes an ultra hard equation of states w = 1 for very early universe. Both phases relax to a pressure less fluid w = 0 for late universe (corresponding to the limit m ? ?)

  19. Hydrodynamics with conserved current via AdS/CFT correspondence in the Maxwell-Gauss-Bonnet gravity

    SciTech Connect (OSTI)

    Hu Yapeng; Sun Peng; Zhang Jianhui [Center for High-Energy Physics, Peking University, Beijing 100871 (China)

    2011-06-15T23:59:59.000Z

    Using the AdS/CFT correspondence, we study the hydrodynamics with conserved current from the dual Maxwell-Gauss-Bonnet gravity. After constructing the perturbative solution to the first order based on the boosted black brane solution in the bulk Maxwell-Gauss-Bonnet gravity, we extract the stress tensor and conserved current of the dual conformal fluid on its boundary, and also find the effect of the Gauss-Bonnet term on the dual conformal fluid. Our results show that the Gauss-Bonnet term can affect the parameters such as the shear viscosity {eta}, entropy density s, thermal conductivity {kappa} and electrical conductivity {sigma}. However, it does not affect the so-called Wiedemann-Franz law which relates {kappa} to {sigma}, while it affects the ratio {eta}/s. In addition, another interesting result is that {eta}/s can also be affected by the bulk Maxwell field in our case, which is consistent with some previous results predicted through the Kubo formula. Moreover, the anomalous magnetic and vortical effects by adding the Chern-Simons term are also considered in our case in the Maxwell-Gauss-Bonnet gravity.

  20. Higgs boson decay to mu mubar gamma

    E-Print Network [OSTI]

    Ali Abbasabadi; Wayne W. Repko

    2000-04-17T23:59:59.000Z

    The Higgs boson decay, H -> mu mubar gamma, is studied in the Standard Model at the tree and one-loop levels. It is shown that for Higgs boson masses above 110 GeV, the contribution to the radiative width from the one-loop level exceeds the contribution from the tree level, and for Higgs boson masses above 140 GeV, it even exceeds the contribution from the tree level decay H -> mu mubar. We also show that the contributions to the radiative decay width from the interference terms between the tree and one-loop diagrams are negligible.

  1. Gamma Ray Burst Neutrinos Probing Quantum Gravity

    E-Print Network [OSTI]

    M. C. Gonzalez-Garcia; F. Halzen

    2006-11-28T23:59:59.000Z

    Very high energy, short wavelength, neutrinos may interact with the space-time foam predicted by theories of quantum gravity. They would propagate like light through a crystal lattice and be delayed, with the delay depending on the energy. This will appear to the observer as a violation of Lorenz invariance. Back of the envelope calculations imply that observations of neutrinos produced by gamma ray bursts may reach Planck-scale sensitivity. We revisit the problem considering two essential complications: the imprecise timing of the neutrinos associated with their poorly understood production mechanism in the source and the indirect nature of their energy measurement made by high energy neutrino telescopes.

  2. Can Naked Singularities Yield Gamma Ray Bursts?

    E-Print Network [OSTI]

    H. M. Antia

    1998-07-09T23:59:59.000Z

    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.

  3. Puzzles of Galactic continuum gamma rays

    E-Print Network [OSTI]

    I. V. Moskalenko; A. W. Strong

    1998-11-14T23:59:59.000Z

    Inverse Compton scattering appears to play a more important role in the diffuse Galactic continuum emission than previously thought, from MeV to GeV energies. We compare models having a large inverse Compton component with EGRET data, and find good agreement in the longitude and latitude distributions at low and high energies. We test an alternative explanation for the >1 GeV gamma-ray excess, the hard nucleon spectrum, using secondary antiprotons and positrons. At lower energies to fit the COMPTEL and OSSE data as diffuse emission requires either a steep upturn in the electron spectrum below 200 MeV or a population of discrete sources.

  4. Gamma-Ray Bursts observed by INTEGRAL

    E-Print Network [OSTI]

    S. Mereghetti

    2003-12-12T23:59:59.000Z

    During the first six months of operations, six Gamma Ray Bursts (GRBs) have been detected in the field of view of the INTEGRAL instruments and localized by the INTEGRAL Burst Alert System (IBAS): a software for the automatic search of GRBs and the rapid distribution of their coordinates. I describe the current performances of IBAS and review the main results obtained so far. The coordinates of the latest burst localized by IBAS, GRB 031203, have been distributed within 20 s from the burst onset and with an uncertainty radius of only 2.7 arcmin.

  5. Classification of Fermi Gamma-RAY Bursts

    E-Print Network [OSTI]

    Horvath, I; Hakkila, J; Bagoly, Z; Preece, R D

    2015-01-01T23:59:59.000Z

    The Fermi GBM Catalog has been recently published. Previous classification analyses of the BATSE, RHESSI, BeppoSAX, and Swift databases found three types of gamma-ray bursts. Now we analyzed the GBM catalog to classify the GRBs. PCA and Multiclustering analysis revealed three groups. Validation of these groups, in terms of the observed variables, shows that one of the groups coincides with the short GRBs. The other two groups split the long class into a bright and dim part, as defined by the peak flux. Additional analysis is needed to determine whether this splitting is only a mathematical byproduct of the analysis or has some real physical meaning.

  6. Gamma Radiation & X-Rays

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist.Newof EnergyFunding OpportunityF G FGalactic ScaleGameGamma

  7. A New Determination Of The Diffuse Galactic and Extragalactic Gamma-Ray Emission

    E-Print Network [OSTI]

    Moskalenko, Igor V.

    for the distribution of galactic diffuse gamma-rays. We compare different propagation models with gamma-ray spectraA New Determination Of The Diffuse Galactic and Extragalactic Gamma-Ray Emission Andrew W. Strong1 for the apparent excess emission observed at GeV gamma-rays. We find that a population of hard-spectrum gamma-ray

  8. X-RAYRICH GAMMA-RAY BURSTS, PHOTOSPHERES, AND VARIABILITY P. Meszaros,1,2

    E-Print Network [OSTI]

    Zhang, Bing

    X-RAY­RICH GAMMA-RAY BURSTS, PHOTOSPHERES, AND VARIABILITY P. Me´sza´ros,1,2 E. Ramirez-Ruiz,3 M. J of the observational gamma-ray variability-luminosity relation. Subject headings: gamma rays: bursts -- radiation mechanisms: nonthermal 1. INTRODUCTION Gamma-ray burst (GRB) light curves at gamma-ray ener- gies are often

  9. Compton scattering effects on the duration of terrestrial gamma-ray flashes

    E-Print Network [OSTI]

    Pasko, Victor

    ; published 18 January 2012. [1] Terrestrial gamma-ray flashes (TGFs) are gamma-ray bursts detected from space) recently discovered by the gamma-ray burst monitor (GBM) aboard the Fermi Gamma-Ray Space Telescope. Introduction [2] Terrestrial gamma-ray flashes (TGFs) are bursts of high-energy photons originating from

  10. OBSERVATIONS OF THE PROMPT GAMMA-RAY EMISSION OF GRB 070125 Eric C. Bellm,1

    E-Print Network [OSTI]

    California at Berkeley, University of

    2007 November 13; accepted 2008 July 25 ABSTRACT The long, bright gamma-ray burst GRB 070125: gamma rays: bursts 1. INTRODUCTION The prompt gamma-ray emission of gamma-ray bursts (GRBs) is the mostOBSERVATIONS OF THE PROMPT GAMMA-RAY EMISSION OF GRB 070125 Eric C. Bellm,1 Kevin Hurley,1 Valentin

  11. Study of Celestial Objects with Very High Energy Gamma Rays CANGAROO III

    E-Print Network [OSTI]

    Enomoto, Ryoji

    ), the doppler boosting of secondary gamma-rays is sufficient to produce TeV gamma-rays. Gamma-ray bursts: Fireballs expanding with relativistic speed explain gamma-ray bursts at cosmological distancesStudy of Celestial Objects with Very High Energy Gamma Rays CANGAROO III Project Description

  12. Search for GeV Emission from Gamma-Ray Bursts Using Milagro Scaler Data

    E-Print Network [OSTI]

    California at Santa Cruz, University of

    Search for GeV Emission from Gamma-Ray Bursts Using Milagro Scaler Data D. A. Williams to search for high energy emission from a sample of 98 gamma-ray bursts (GRB) detected from January 2000: gamma-ray sources; gamma-ray bursts; astronomical observations: gamma-ray PACS: 98.70.Rz,95.85.Pw Air

  13. Observation of eta '(c) production in gamma gamma fusion at CLEO

    E-Print Network [OSTI]

    Besson, David Zeke

    2004-04-01T23:59:59.000Z

    ) = 115.1 +/- 2.0 MeV and DeltaM(hf)(2S) = 43.1 +/- 3.4 MeV. Assuming that the eta(c) and eta(c)' have equal branching fractions to K(s)Kpi, we obtain Gamma(gammagamma)(eta(c)') = 1.3 +/- 0.6 keV....

  14. The Animated Gamma-ray Sky Revealed by the Fermi Gamma-ray Space Telescope

    ScienceCinema (OSTI)

    Isabelle Grenier

    2010-01-08T23:59:59.000Z

    The Fermi Gamma-ray Space Telescope has been observing the sky in gamma-rays since August 2008.  In addition to breakthrough capabilities in energy coverage (20 MeV-300 GeV) and angular resolution, the wide field of view of the Large Area Telescope enables observations of 20% of the sky at any instant, and of the whole sky every three hours. It has revealed a very animated sky with bright gamma-ray bursts flashing and vanishing in minutes, powerful active galactic nuclei flaring over hours and days, many pulsars twinkling in the Milky Way, and X-ray binaries shimmering along their orbit. Most of these variable sources had not been seen by the Fermi predecessor, EGRET, and the wealth of new data already brings important clues to the origin of the high-energy emission and particles powered by the compact objects. The telescope also brings crisp images of the bright gamma-ray emission produced by cosmic-ray interactions in the interstellar medium, thus allowing to measure the cosmic nuclei and electron spectra across the Galaxy, to weigh interstellar clouds, in particular in the dark-gas phase. The telescope sensitivity at high energy will soon provide useful constraints on dark-matter annihilations in a variety of environments. I will review the current results and future prospects of the Fermi mission.

  15. Verification of Gamma Knife extend system based fractionated treatment planning using EBT2 film

    SciTech Connect (OSTI)

    Natanasabapathi, Gopishankar; Bisht, Raj Kishor [Gamma Knife Unit, Department of Neurosurgery, Neurosciences Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029 (India)] [Gamma Knife Unit, Department of Neurosurgery, Neurosciences Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029 (India)

    2013-12-15T23:59:59.000Z

    Purpose: This paper presents EBT2 film verification of fractionated treatment planning with the Gamma Knife (GK) extend system, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery.Methods: A human head shaped phantom simulated the verification process for fractionated Gamma Knife treatment. Phantom preparation for Extend Frame based treatment planning involved creating a dental impression, fitting the phantom to the frame system, and acquiring a stereotactic computed tomography (CT) scan. A CT scan (Siemens, Emotion 6) of the phantom was obtained with following parameters: Tube voltage—110 kV, tube current—280 mA, pixel size—0.5 × 0.5 and 1 mm slice thickness. A treatment plan with two 8 mm collimator shots and three sectors blocking in each shot was made. Dose prescription of 4 Gy at 100% was delivered for the first fraction out of the two fractions planned. Gafchromic EBT2 film (ISP Wayne, NJ) was used as 2D verification dosimeter in this process. Films were cut and placed inside the film insert of the phantom for treatment dose delivery. Meanwhile a set of films from the same batch were exposed from 0 to 12 Gy doses for calibration purposes. An EPSON (Expression 10000 XL) scanner was used for scanning the exposed films in transparency mode. Scanned films were analyzed with inhouse written MATLAB codes.Results: Gamma index analysis of film measurement in comparison with TPS calculated dose resulted in high pass rates >90% for tolerance criteria of 1%/1 mm. The isodose overlay and linear dose profiles of film measured and computed dose distribution on sagittal and coronal plane were in close agreement.Conclusions: Through this study, the authors propose treatment verification QA method for Extend frame based fractionated Gamma Knife radiosurgery using EBT2 film.

  16. Strategy to detect the gravitational radiation counterpart of gamma-ray bursts

    E-Print Network [OSTI]

    S. Bonazzola; E. Gourgoulhon

    1998-01-20T23:59:59.000Z

    Both observational and theoretical rates of binary neutron star coalescence give low prospects for detection of a single event by the initial LIGO/VIRGO interferometers. However, by utilizing at the best all the a priori information on the expected signal, a positive detection can be achieved. This relies on the hypothesis that $\\gamma$-ray bursts are the electromagnetic signature of neutron star coalescences. The information about the direction of the source can then be used to add in phase the signals from different detectors in order (i) to increase the signal-to-noise ratio and (ii) to make the noise more Gaussian. Besides, the information about the time of arrival can be used to drastically decrease the observation time and thereby the false alarm rate. Moreover the fluence of the $\\gamma$-ray emission gives some information about the amplitude of the gravitational signal. One can then add the signals from $\\sim 10^4$ observation boxes ($\\sim$ number of $\\gamma$-ray bursts during 10 years) to yield a positive detection. Such a detection, based on the Maximum a Posteriori Probability Criterium, is a minimal one, in the sense that no information on the position and time of the events, nor on any parameter of the model, is collected. The advantage is that this detection requires an improvement of the detector sensitivity by a factor of only $\\sim 1.5$ with respect to the initial LIGO/VIRGO interferometers, and that, if positive, it will confirm the $\\gamma$-ray burst model.

  17. Observational Constraints on Cosmological Models with the Updated Long Gamma-Ray Bursts

    E-Print Network [OSTI]

    Hao Wei

    2010-08-16T23:59:59.000Z

    In the present work, by the help of the newly released Union2 compilation which consists of 557 Type Ia supernovae (SNIa), we calibrate 109 long Gamma-Ray Bursts (GRBs) with the well-known Amati relation, using the cosmology-independent calibration method proposed by Liang {\\it et al.}. We have obtained 59 calibrated high-redshift GRBs which can be used to constrain cosmological models without the circularity problem (we call them ``Hymnium'' GRBs sample for convenience). Then, we consider the joint constraints on 7 cosmological models from the latest observational data, namely, the combination of 557 Union2 SNIa dataset, 59 calibrated Hymnium GRBs dataset (obtained in this work), the shift parameter $R$ from the WMAP 7-year data, and the distance parameter $A$ of the measurement of the baryon acoustic oscillation (BAO) peak in the distribution of SDSS luminous red galaxies. We also briefly consider the comparison of these 7 cosmological models.

  18. Can black-hole neutrino-cooled disks power short gamma-ray bursts?

    E-Print Network [OSTI]

    Liu, Tong; Hou, Shu-Jin; Gu, Wei-Min

    2015-01-01T23:59:59.000Z

    Stellar-mass black holes (BHs) surrounded by neutrino-dominated accretion flows (NDAFs) are the plausible candidates to power gamma-ray bursts (GRBs) via neutrinos emission and their annihilation. The progenitors of short-duration GRBs (SGRBs) are generally considered to be compact binaries mergers. According to the simulation results, the disk mass of the NDAF has been limited after merger events. We can estimate such disk mass by using the current SGRB observational data and fireball model. The results show that the disk mass of a certain SGRB mainly depends on its output energy, jet opening angle, and central BH characteristics. Even for the extreme BH parameters, some SGRBs require massive disks, which approach or exceed the limits in simulations. We suggest that there may exist alternative magnetohydrodynamic processes or some mechanisms increasing the neutrino emission to produce SGRBs with the reasonable BH parameters and disk mass.

  19. Gamma-ray burst prompt emission light curves and power density spectra in the ICMART model

    SciTech Connect (OSTI)

    Zhang, Bo [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Zhang, Bing, E-mail: bozhang@physics.unlv.edu, E-mail: zhang@physics.unlv.edu [Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154 (United States)

    2014-02-20T23:59:59.000Z

    In this paper, we simulate the prompt emission light curves of gamma-ray bursts (GRBs) within the framework of the Internal-Collision-induced MAgnetic Reconnection and Turbulence (ICMART) model. This model applies to GRBs with a moderately high magnetization parameter ? in the emission region. We show that this model can produce highly variable light curves with both fast and slow components. The rapid variability is caused by many locally Doppler-boosted mini-emitters due to turbulent magnetic reconnection in a moderately high ? flow. The runaway growth and subsequent depletion of these mini-emitters as a function of time define a broad slow component for each ICMART event. A GRB light curve is usually composed of multiple ICMART events that are fundamentally driven by the erratic GRB central engine activity. Allowing variations of the model parameters, one is able to reproduce a variety of light curves and the power density spectra as observed.

  20. Gamma-Ray Burst Prompt Emission Light Curves and Power Density Spectra in the ICMART Model

    E-Print Network [OSTI]

    Zhang, Bo

    2013-01-01T23:59:59.000Z

    In this paper, we simulate the prompt emission light curves of gamma-ray bursts (GRBs) within the framework of the Internal-Collision-induced MAgnetic Reconnection and Turbulence (ICMART) model. This model applies to GRBs with a moderately-high magnetization parameter $\\sigma$ in the emission region. We show that this model can produce highly variable light curves with both fast and slow components. The rapid variability is caused by many locally Doppler-boosted mini-emitters due to turbulent magnetic reconnection in a moderately-high-$\\sigma$ flow. The run-away growth and subsequent depletion of these mini-emitters as a function time define a broad slow component for each ICMART event. A GRB light curve is usually composed of multiple ICMART events that are fundamentally driven by the erratic GRB central engine activity. Allowing variations of the model parameters, one is able to reproduce a variety of light curves and the power density spectra as observed.

  1. Circular geodesics and accretion disks in Janis-Newman-Winicour and Gamma metric

    E-Print Network [OSTI]

    Anirban N. Chowdhury; Mandar Patil; Daniele Malafarina; Pankaj S. Joshi

    2012-04-19T23:59:59.000Z

    We study here circular timelike geodesics in the Janis-Newman-Winicour and Gamma metric spacetimes which contain a strong curvature naked singularity and reduce to the Schwarzschild metric for a specific value of one of the parameters. We show that for both the metrics the range of allowed parameters can be divided into three regimes where structure of the circular geodesics is qualitatively different. It follows that the properties of the accretion disks around such naked singularities can be significantly different from those of disks around black holes. This adds to previous studies showing that if naked singularities exist in nature, their observational signature would be significantly different from that of the black hole.

  2. Parameter Estimation of Gravitational Waves from Precessing BH-NS Inspirals with higher harmonics

    E-Print Network [OSTI]

    R. O'Shaughnessy; B. Farr; E. Ochsner; H. S. Cho; V. Raymond; C. Kim; C. H. Lee

    2014-04-11T23:59:59.000Z

    Precessing black hole-neutron star (BH-NS) binaries produce a rich gravitational wave signal, encoding the binary's nature and inspiral kinematics. Using the lalinference\\_mcmc Markov-chain Monte Carlo parameter estimation code, we use two fiducial examples to illustrate how the geometry and kinematics are encoded into the modulated gravitational wave signal, using coordinates well-adapted to precession. Even for precessing binaries, we show the performance of detailed parameter estimation can be estimated by "effective" estimates: comparisons of a prototype signal with its nearest neighbors, adopting a fixed sky location and idealized two-detector network. We use detailed and effective approaches to show higher harmonics provide nonzero but small local improvement when estimating the parameters of precessing BH-NS binaries. That said, we show higher harmonics can improve parameter estimation accuracy for precessing binaries ruling out approximately-degenerate source orientations. Our work illustrates quantities gravitational wave measurements can provide, such as reliable component masses and the precise orientation of a precessing short gamma ray burst progenitor relative to the line of sight. "Effective" estimates may provide a simple way to estimate trends in the performance of parameter estimation for generic precessing BH-NS binaries in next-generation detectors. For example, our results suggest that the orbital chirp rate, precession rate, and precession geometry are roughly-independent observables, defining natural variables to organize correlations in the high-dimensional BH-NS binary parameter space.

  3. Formulation and solution of the delayed gamma dose rate problem using the concept of effective delayed gamma production cross section

    SciTech Connect (OSTI)

    Liew, S.L.; Ku, L.P.

    1989-06-01T23:59:59.000Z

    With appropriate approximations, the delayed gamma dose rate problem can be formulated in terms of the effective delayed gamma production cross section. The coupled neutron-delayed-gamma transport equations then take the same form as the coupled neutron-prompt-gamma transport equations and they can, therefore, be solved directly in the same manner. This eliminates the need for the tedious and error prone flux coupling step in conventional calculations. Mathematical formulation and solution algorithms are derived. The advantages of this method are illustrated by an example of its application in the solution of a practical design problem. 62 refs., 10 figs., 1 tab.

  4. Relativistic Winds from Compact Gamma-ray Sources: I. Radiative Acceleration in the Klein-Nishina Regime

    E-Print Network [OSTI]

    Piero Madau; Christopher Thompson

    1999-11-30T23:59:59.000Z

    We consider the radiative acceleration to relativistic bulk velocities of a cold, optically thin plasma which is exposed to an external source of gamma-rays. The flow is driven by radiative momentum input to the gas, the accelerating force being due to Compton scattering in the relativistic Klein-Nishina limit. The bulk Lorentz factor of the plasma, Gamma, derived as a function of distance from the radiating source, is compared with the corresponding result in the Thomson limit. Depending on the geometry and spectrum of the radiation field, we find that particles are accelerated to the asymptotic Lorentz factor at infinity much more rapidly in the relativistic regime; and the radiation drag is reduced as blueshifted, aberrated photons experience a decreased relativistic cross section and scatter preferentially in the forward direction. The random energy imparted to the plasma by gamma-rays can be converted into bulk motion if the hot particles execute many Larmor orbits before cooling. This `Compton afterburn' may be a supplementary source of momentum if energetic leptons are injected by pair creation, but can be neglected in the case of pure Klein-Nishina scattering. Compton drag by side-scattered radiation is shown to be more important in limiting the bulk Lorentz factor than the finite inertia of the accelerating medium. The processes discussed here may be relevant to a variety of astrophysical situations where luminous compact sources of hard X- and gamma-ray photons are observed, including active galactic nuclei, galactic black hole candidates, and gamma-ray bursts.

  5. Composition and apparatus for detecting gamma radiation

    DOE Patents [OSTI]

    Hofstetter, K.J.

    1994-08-09T23:59:59.000Z

    A gamma radiation detector and a radioluminescent composition for use therein. The detector includes a radioluminescent composition that emits light in a characteristic wavelength region when exposed to gamma radiation, and means for detecting said radiation. The composition contains a scintillant such as anglesite (PbSO[sub 4]) or cerussite (PbCO[sub 3]) incorporated into an inert, porous glass matrix via a sol-gel process. Particles of radiation-sensitive scintillant are added to, a sol solution. The mixture is polymerized to form a gel, then dried under conditions that preserve the structural integrity and radiation sensitivity of the scintillant. The final product is a composition containing the uniformly-dispersed scintillant in an inert, optically transparent and highly porous matrix. The composition is chemically inert and substantially impervious to environmental conditions including changes in temperature, air pressure, and so forth. It can be fabricated in cylinders, blocks with holes therethrough for flow of fluid, sheets, surface coatings, pellets or other convenient shapes. 3 figs.

  6. Gamma neutron assay method and apparatus

    DOE Patents [OSTI]

    Cole, J.D.; Aryaeinejad, R.; Greenwood, R.C.

    1995-01-03T23:59:59.000Z

    The gamma neutron assay technique is an alternative method to standard safeguards techniques for the identification and assaying of special nuclear materials in a field or laboratory environment, as a tool for dismantlement and destruction of nuclear weapons, and to determine the isotopic ratios for a blend-down program on uranium. It is capable of determining the isotopic ratios of fissionable material from the spontaneous or induced fission of a sample to within approximately 0.5%. This is based upon the prompt coincidence relationships that occur in the fission process and the proton conservation and quasi-conservation of nuclear mass (A) that exists between the two fission fragments. The system is used in both passive (without an external neutron source) and active (with an external neutron source) mode. The apparatus consists of an array of neutron and gamma-ray detectors electronically connected to determine coincident events. The method can also be used to assay radioactive waste which contains fissile material, even in the presence of a high background radiation field. 7 figures.

  7. Gamma neutron assay method and apparatus

    DOE Patents [OSTI]

    Cole, Jerald D. (Idaho Falls, ID); Aryaeinejad, Rahmat (Idaho Falls, ID); Greenwood, Reginald C. (Idaho Falls, ID)

    1995-01-01T23:59:59.000Z

    The gamma neutron assay technique is an alternative method to standard safeguards techniques for the identification and assaying of special nuclear materials in a field or laboratory environment, as a tool for dismantlement and destruction of nuclear weapons, and to determine the isotopic ratios for a blend-down program on uranium. It is capable of determining the isotopic ratios of fissionable material from the spontaneous or induced fission of a sample to within approximately 0.5%. This is based upon the prompt coincidence relationships that occur in the fission process and the proton conservation and quasi-conservation of nuclear mass (A) that exists between the two fission fragments. The system is used in both passive (without an external neutron source and active (with an external neutron source) mode. The apparatus consists of an array of neutron and gamma-ray detectors electronically connected to determine coincident events. The method can also be used to assay radioactive waste which contains fissile material, even in the presence of a high background radiation field.

  8. Radio flares from gamma-ray bursts

    E-Print Network [OSTI]

    Kopac, D; Kobayashi, S; Virgili, F J; Harrison, R; Japelj, J; Guidorzi, C; Melandri, A; Gomboc, A

    2015-01-01T23:59:59.000Z

    We present predictions of centimeter and millimeter radio emission from reverse shocks in the early afterglows of gamma-ray bursts with the goal of determining their detectability with current and future radio facilities. Using a range of GRB properties, such as peak optical brightness and time, isotropic equivalent gamma-ray energy and redshift, we simulate radio light curves in a framework generalized for any circumburst medium structure and including a parametrization of the shell thickness regime that is more realistic than the simple assumption of thick- or thin-shell approximations. Building on earlier work by Mundell et al. (2007) and Melandri et al. (2010) in which the typical frequency of the reverse shock was suggested to lie at radio, rather than optical wavelengths at early times, we show that the brightest and most distinct reverse-shock radio signatures are detectable up to 0.1 -- 1 day after the burst, emphasizing the need for rapid radio follow-up. Detection is easier for bursts with later opt...

  9. A fast algorithm for gamma evaluation in 3D

    SciTech Connect (OSTI)

    Wendling, Markus; Zijp, Lambert J.; McDermott, Leah N.; Smit, Ewoud J.; Sonke, Jan-Jakob; Mijnheer, Ben J.; Herk, Marcel van [Department of Radiation Oncology, Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands)

    2007-05-15T23:59:59.000Z

    The {gamma}-evaluation method is a tool by which dose distributions can be compared in a quantitative manner combining dose-difference and distance-to-agreement criteria. Since its introduction, the {gamma} evaluation has been used in many studies and is on the verge of becoming the preferred dose distribution comparison method, particularly for intensity-modulated radiation therapy (IMRT) verification. One major disadvantage, however, is its long computation time, which especially applies to the comparison of three-dimensional (3D) dose distributions. We present a fast algorithm for a full 3D {gamma} evaluation at high resolution. Both the reference and evaluated dose distributions are first resampled on the same grid. For each point of the reference dose distribution, the algorithm searches for the best point of agreement according to the {gamma} method in the evaluated dose distribution, which can be done at a subvoxel resolution. Speed, computer memory efficiency, and high spatial resolution are achieved by searching around each reference point with increasing distance in a sphere, which has a radius of a chosen maximum search distance and is interpolated 'on-the-fly' at a chosen sample step size. The smaller the sample step size and the larger the differences between the dose distributions, the longer the {gamma} evaluation takes. With decreasing sample step size, statistical measures of the 3D {gamma} distribution converge. Two clinical examples were investigated using 3% of the prescribed dose as dose-difference and 0.3 cm as distance-to-agreement criteria. For 0.2 cm grid spacing, the change in {gamma} indices was negligible below a sample step size of 0.02 cm. Comparing the full 3D {gamma} evaluation and slice-by-slice 2D {gamma} evaluations ('2.5D') for these clinical examples, the {gamma} indices improved by searching in full 3D space, with the average {gamma} index decreasing by at least 8%.

  10. THE BRIGHT GAMMA-RAY BURST OF 2000 FEBRUARY 10: A CASE STUDY OF AN OPTICALLY DARK GAMMA-RAY BURST

    E-Print Network [OSTI]

    Fynbo, Johan

    THE BRIGHT GAMMA-RAY BURST OF 2000 FEBRUARY 10: A CASE STUDY OF AN OPTICALLY DARK GAMMA-RAY BURST L Received 2002 January 16; accepted 2002 June 8 ABSTRACT The gamma-ray burst GRB 000210 had the highest: observations -- gamma-rays: bursts 1. INTRODUCTION It is observationally well established that about half

  11. Index of selected OSW correspondence. EPA Office of Solid Waste, updated as of December 1995

    SciTech Connect (OSTI)

    NONE

    1995-12-01T23:59:59.000Z

    This document is an index of selected Office of Solid Waste (OSW) correspondence that has been developed by the staff of EPA`s RCRA/UST, Superfund, and EPCR Hotline for use as a research tool about RCRA issues. This index organizes summaries of over 900 letters and memoranda issued by OSW. Addressed primarily to persons in the regulated community as well as state and Regional regulators, the correspondence represents past EPA interpretations of the RCRA regulations governing management of solid, hazardous, nd medical wastes. This document is designed for use by readers familiar with the federal RCRA program and the relevant regulations. The index`s organization parallels that of 40 CFR Parts 258 to 279. The document indexes each letter or memorandum under the apropriate CFR citation (or citations) which the letter or memorandum clarifies.

  12. Compton Recoil Electron Tracking With the TIGRE Gamma-Ray Balloon Experiment

    E-Print Network [OSTI]

    Kamiya, Kaoru

    2011-01-01T23:59:59.000Z

    AGNs), pulsars, gamma-ray bursts, cosmic ray interactionssensitive to cosmic gamma-ray bursts in the energy range ofGalactic center, a single gamma-ray burst which occurred 10

  13. Global episodic beta/gamma synchrony 1 Freeman & Rogers A neurobiological theory of meaning in perception.

    E-Print Network [OSTI]

    Freeman, Walter J.

    Global episodic beta/gamma synchrony 1 Freeman & Rogers A neurobiological theory of meaning words: analytic phase, beta oscillation, EEG synchronization, gamma oscillation, Hilbert transform, phase transition Running Title: Global episodic beta/gamma synchrony #12;Global episodic beta

  14. The Search for Muon Neutrinos from Northern Hemisphere Gamma-Ray Bursts with AMANDA

    E-Print Network [OSTI]

    Achterberg, A.; IceCube Collaboration

    2008-01-01T23:59:59.000Z

    see also the Swift Gamma-Ray Burst Mission Page: http://from Northern Hemisphere Gamma-Ray Bursts with AMANDA A.Northern Hemisphere Gamma-Ray Bursts with AMANDA The IceCube

  15. Search for muon neutrinos from Gamma-Ray Bursts with the IceCube neutrino telescope

    E-Print Network [OSTI]

    Abbasi, R.

    2010-01-01T23:59:59.000Z

    2009, GCN: The Gamma ray bursts Coordinates Network, http://for muon neutrinos from Gamma-Ray Bursts with the IceCubeMereghetti, S. 2004, in Gamma-ray Bursts: 30 Years of

  16. Long gamma-ray bursts and core-collapse supernovae have different environments

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    Progenitor Stars of Gamma-Ray Bursts. Astrophys. J. 637, 45.massive stars towards gamma-ray bursts. Astr. Astrophys.On the Lyalpha emission from gamma-ray burst host galaxies:

  17. Measurement of uranium enrichment by gamma spectroscopy: result of an experimental design

    E-Print Network [OSTI]

    , Gamma Spectrometry, uranium enrichment #12;PAPER Measurement of uranium enrichment by gamma spectroscopy: result of an experimental design Gamma spectroscopy is commonly used in nuclear safeguards to measure uranium enrichment. An experimental

  18. THE EFFECT OF RADON TRANSPORT IN GROUNDWATER UPON GAMMA-RAY BOREHOLE LOGS

    E-Print Network [OSTI]

    Nelson, P.H.

    2010-01-01T23:59:59.000Z

    f o r Uranium by Gamma-Ray Spectrometry." Geophysics, 45,222 Emanation from Gamma Spectrometry on Stripa Samples B.222 Emanation from Gamma Spectrometry on Stripa Samples B.

  19. GRB 020410: A Gamma-ray burst afterglow discovered by its supernova light

    E-Print Network [OSTI]

    2004-01-01T23:59:59.000Z

    Training Network “Gamma-Ray Bursts: An Enigma and a Tool”,Journal GRB 020410: A Gamma-Ray Burst Afterglow DiscoveredSubject headings: gamma rays: bursts – supernova: general

  20. Galaxy Structural Parameters in Source Extractor

    E-Print Network [OSTI]

    B. W. Holwerda

    2007-10-16T23:59:59.000Z

    Over the last decade, the Concentration, Asymmetry and Smoothness (CAS), as well as the M20 and GINI parameters have become popular to automatically classify distant galaxies in images. Ellipticals, spirals and irregular galaxies all appear to occupy different regions of this parameter space. At the same time, the Source Extractor (SE) program has become the mainstay to produce ob ject catalogs from large image surveys. A logical next step would be to incorporate the structural parameters into the Source Extractor software. There are however several problems that arise: 1) the CAS parameters are fits to the images and Source Extractor eschews fits in the interest of speed, 2) the definition of the structural parameters changed over time. Now that there is a clear and agreed-upon definition of the structural parameters, I am incorporating computed versions in the Source Extractor code (v2.5). The fitted CAS parameters are available for the GOODS-N/S fields and I compare the computed structural parameters to those found by the previous fits. My goal is to expand the source structure information in Source Extractor catalogs in order to improve automatic identification of sources, specifically of distant galaxies. The computed parameters perform reasonably close to the fitted versions but noise appears in faint ob jects due to a lack of information. For a subset of objects, the asymmetry signal is outside the SE boundaries and Smoothness still fails to compute for many ob jects. Type classification based on the SE parameters still lacks resolving power.

  1. Current Trends in Gamma Ray Detection for Radiological Emergency Response

    SciTech Connect (OSTI)

    Mukhopadhyay, S., Guss, P., Maurer, R.

    2011-08-18T23:59:59.000Z

    Passive and active detection of gamma rays from shielded radioactive materials, including special nuclear materials, is an important task for any radiological emergency response organization. This article reports on the current trends and status of gamma radiation detection objectives and measurement techniques as applied to nonproliferation and radiological emergencies.

  2. astrophysical gamma ray: Topics by E-print Network

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

    astrophysical gamma ray First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Astrophysical Gamma Ray...

  3. airborne gamma ray: Topics by E-print Network

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

    airborne gamma ray First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Digital Logarithmic Airborne Gamma...

  4. aerial gamma ray: Topics by E-print Network

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

    aerial gamma ray First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Cosmic Rays: What Gamma Rays Can Say...

  5. Delayed neutron data and group parameters for 43 fissioning systems

    SciTech Connect (OSTI)

    Brady, M.C. (Oak Ridge National Lab., TN (USA)); England, T.R. (Los Alamos National Lab., NM (USA))

    1989-10-01T23:59:59.000Z

    The quality and quantity of delayed neutron precursor data have greatly improved over the past decade and a half. Supplementation of the data with model calculations and the use of models to extend the number of precursors to 271 is now practical. These data, along with other improved fission product parameters, permit direct calculations of aggregate behavior for many fissioning nuclides. The results can still be approximated using a few (usually six) temporal groups, including corresponding spectra, as in past practice for reactor physics. An extensive effort to provide a complete set of evaluated data is summarized, with an emphasis on its use to generate the temporal approximations; precursor data and group values are intended for inclusion in ENDF/B-VI.

  6. Total and partial cross sections of the $^{112}$Sn($\\alpha,\\gamma$)$^{116}$Te reaction measured via in-beam $\\gamma$-ray spectroscopy

    E-Print Network [OSTI]

    Netterdon, L; Scholz, P; Zilges, A

    2015-01-01T23:59:59.000Z

    An extended database of experimental data is needed to address uncertainties of the nuclear-physics input parameters for Hauser-Feshbach calculations. Especially $\\alpha$+nucleus optical model potentials at low energies are not well known. The in-beam technique with an array of high-purity germanium (HPGe) detectors was successfully applied to the measurement of absolute cross sections of an ($\\alpha$,$\\gamma$) reaction on a heavy nucleus at sub-Coulomb energies. The total and partial cross-section values were measured by means of in-beam $\\gamma$-ray spectroscopy. Total and partial cross sections were measured at four different $\\alpha$-particle energies from $E_\\alpha = 10.5$ MeV to $E_\\alpha = 12$ MeV. The measured total cross-section values are in excellent agreement with previous results obtained with the activation technique, which proves the validity of the applied method. The experimental data was compared to Hauser-Feshbach calculations using the nuclear reaction code TALYS. A modified version of the...

  7. Gamma decay of unbound states following neutron capture

    SciTech Connect (OSTI)

    Raman, S.

    1982-01-01T23:59:59.000Z

    Neutron capture ..gamma..-ray spectroscopy is a powerful technique to study the ..gamma..-decay of unbound levels just above the neutron separation energy. It is generally believed that the (n,..gamma..) reaction proceeds by way of a compound nucleus reaction of great complexity; and, therefore, the capture ..gamma..-ray spectrum should be describable in terms of statistical laws. However, measurements have shown that effects are present due to single-particle motions and due to giant resonances. The study of (n,..gamma..) spectra averaged over as many resonances as possible provides one of the best experimental means of directly obtaining reliable values for radiative transition probabilities from highly excited nuclear states. In very select cases, unbound levels which are populated in allowed ..beta.. decay can also be observed as neutron resonances. These ideas are illustrated with examples of recent data.

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

    E-Print Network [OSTI]

    Andre Rubbia; Alexander Sakharov

    2008-09-03T23:59:59.000Z

    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.

  9. The supernova/gamma-ray burst/jet connection

    E-Print Network [OSTI]

    Hjorth, Jens

    2013-01-01T23:59:59.000Z

    The observed association between supernovae and gamma-ray bursts represents a cornerstone in our understanding of the nature of gamma-ray bursts. The collapsar model provides a theoretical framework for this connection. A key element is the launch of a bi-polar jet (seen as a gamma-ray burst). The resulting hot cocoon disrupts the star while the 56Ni produced gives rise to radioactive heating of the ejecta, seen as a supernova. In this discussion paper I summarise the observational status of the supernova/gamma-ray burst connection in the context of the 'engine' picture of jet-driven supernovae and highlight SN 2012bz/GRB 120422A -- with its luminous supernova but intermediate high-energy luminosity -- as a possible transition object between low-luminosity and jet gamma-ray bursts. The jet channel for supernova explosions may provide new insight into supernova explosions in general.

  10. Collective effects of stellar winds and unidentified gamma-ray sources

    E-Print Network [OSTI]

    Diego F. Torres; Eva Domingo-Santamaria

    2006-11-11T23:59:59.000Z

    We study collective wind configurations produced by a number of massive stars, and obtain densities and expansion velocities of the stellar wind gas that is to be target, in this model, of hadronic interactions. We study the expected $\\gamma$-ray emission from these regions, considering in an approximate way the effect of cosmic ray modulation. We compute secondary particle production (electrons from knock-on interactions and electrons and positrons from charged pion decay), and solve the loss equation with ionization, synchrotron, bremsstrahlung, inverse Compton, and expansion losses. We provide examples where configurations can produce sources for GLAST satellite, and the MAGIC, HESS, or VERITAS telescopes in non-uniform ways, i.e., with or without the corresponding counterparts. We show that in all cases we studied no EGRET source is expected.

  11. THE INTERPLANETARY NETWORK SUPPLEMENT TO THE FERMI GBM CATALOG OF COSMIC GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Hurley, K. [University of California, Berkeley, Space Sciences Laboratory, 7 Gauss Way, Berkeley, CA 94720-7450 (United States); Pal'shin, V. D.; Aptekar, R. L.; Golenetskii, S. V.; Frederiks, D. D.; Mazets, E. P.; Svinkin, D. S. [Ioffe Physical Technical Institute, St. Petersburg 194021 (Russian Federation); Briggs, M. S.; Connaughton, V. [University of Alabama in Huntsville, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Meegan, C. [Universities Space Research Association, NSSTC, 320 Sparkman Drive, Huntsville, AL 35805 (United States); Goldsten, J. [Applied Physics Laboratory, Johns Hopkins University, Laurel, MD 20723 (United States); Boynton, W.; Fellows, C.; Harshman, K. [University of Arizona, Department of Planetary Sciences, Tucson, AZ 85721 (United States); Mitrofanov, I. G.; Golovin, D. V.; Kozyrev, A. S.; Litvak, M. L.; Sanin, A. B. [Space Research Institute, 84/32, Profsoyuznaya, Moscow 117997 (Russian Federation); Rau, A., E-mail: khurley@ssl.berkeley.edu [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, Postfach 1312, D-85748 Garching (Germany); and others

    2013-08-15T23:59:59.000Z

    We present Interplanetary Network (IPN) data for the gamma-ray bursts in the first Fermi Gamma-Ray Burst Monitor (GBM) catalog. Of the 491 bursts in that catalog, covering 2008 July 12 to 2010 July 11, 427 were observed by at least one other instrument in the nine-spacecraft IPN. Of the 427, the localizations of 149 could be improved by arrival time analysis (or {sup t}riangulation{sup )}. For any given burst observed by the GBM and one other distant spacecraft, triangulation gives an annulus of possible arrival directions whose half-width varies between about 0.'4 and 32 Degree-Sign , depending on the intensity, time history, and arrival direction of the burst, as well as the distance between the spacecraft. We find that the IPN localizations intersect the 1{sigma} GBM error circles in only 52% of the cases, if no systematic uncertainty is assumed for the latter. If a 6 Degree-Sign systematic uncertainty is assumed and added in quadrature, the two localization samples agree about 87% of the time, as would be expected. If we then multiply the resulting error radii by a factor of three, the two samples agree in slightly over 98% of the cases, providing a good estimate of the GBM 3{sigma} error radius. The IPN 3{sigma} error boxes have areas between about 1 arcmin{sup 2} and 110 deg{sup 2}, and are, on the average, a factor of 180 smaller than the corresponding GBM localizations. We identify two bursts in the IPN/GBM sample that did not appear in the GBM catalog. In one case, the GBM triggered on a terrestrial gamma flash, and in the other, its origin was given as ''uncertain''. We also discuss the sensitivity and calibration of the IPN.

  12. Fresnel lenses for X-ray and Gamma-ray Astronomy

    E-Print Network [OSTI]

    Gerry Skinner; Peter von Ballmoos; Neil Gehrels; John Krizmanic

    2003-08-25T23:59:59.000Z

    Phase Fresnel lenses have the same imaging properties as zone plates, but with the possibility of concentrating all of the incident power into the primary focus, increasing the maximum theoretical efficiency from 11% to close to 100%. For X-rays, and in particular for gamma-rays, large, diffraction-limited phase Fresnel lenses can be made relatively easily. The focal length is very long - for example up to a million kms. However, the correspondingly high `plate-scale' of the image means that the ultra-high (sub-micro-arc-second) angular resolution possible with a diffraction limited gamma-ray lens a few metres in diameter can be exploited with detectors having \\~mm spatial resolution. The potential of such systems for ultra-high angular resolution astronomy, and for attaining the sensitivity improvements desperately needed for certain other studies, are reviewed and the advantages and disadvantages vis-a-vis alternative approaches are discussed. We report on reduced-scale 'proof-of-principle tests' which are planned and on mission studies of the implementation of a Fresnel telescope on a space mission with lens and detector on two spacecraft separated by one million km. Such a telescope would be capable of resolving emission from super-massive black holes on the scale of their event horizons and would have the sensitivity necessary to detect gamma-ray lines from distant supernovae. We show how diffractive/refractive optics leads to a continuum of possible system designs between filled aperture lenses and wideband interferometric arrays.

  13. Uncertainty evaluation of delayed neutron decay parameters

    E-Print Network [OSTI]

    Wang, Jinkai

    2009-05-15T23:59:59.000Z

    .......... 80 Figure 6.1 Fitted E2 from Different Algorithms (Saturation Mode)................... 85 Figure 6.2 Standard Deviations of Fitted Parameter Ratios (Saturation Mode). 92 Figure 6.3 Standard Deviations of Fitted Parameter Ratios (Pulse Mode...)......... 92 Figure 6.4 Standard Deviations of Fitted Parameter Ratios with Group-1 Fixed (Pulse Mode) ........................................................................... 93 Figure 6.5 The Ratios of Different Data Sets to Keepin?s Values...

  14. A novel paradigm for short gamma-ray bursts with extended X-ray emission

    E-Print Network [OSTI]

    Luciano Rezzolla; Pawan Kumar

    2015-01-21T23:59:59.000Z

    The merger of a binary of neutron stars provides natural explanations for many of the features of short gamma-ray bursts (SGRBs), such as the generation of a hot torus orbiting a rapidly rotating black hole, which can then build a magnetic jet and provide the energy reservoir to launch a relativistic outflow. Yet, this scenario has problems explaining the recently discovered long-term and sustained X-ray emission associated with the afterglows of a subclass of SGRBs. We propose a new model that explains how an X-ray afterglow can be sustained by the product of the merger and how the X-ray emission is produced before the corresponding emission in the gamma-band, although it is observed to follow it. Overall, our paradigm combines in a novel manner a number of well-established features of the emission in SGRBs and results from simulations. Because it involves the propagation of an ultra-relativistic outflow and its interaction with a confining medium, the paradigm also highlights a unifying phenomenology between short and long GRBs.

  15. DISCOVERY OF A NEW TeV GAMMA-RAY SOURCE: VER J0521+211

    SciTech Connect (OSTI)

    Archambault, S. [Physics Department, McGill University, Montreal, QC H3A 2T8 (Canada); Arlen, T.; Aune, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Behera, B.; Federici, S. [DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Beilicke, M.; Buckley, J. H.; Bugaev, V. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Bird, R. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Bouvier, A. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Byrum, K. [Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL 60439 (United States); Cesarini, A.; Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Cui, W.; Feng, Q.; Finley, J. P. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Errando, M. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Falcone, A., E-mail: fortin@veritas.sao.arizona.edu, E-mail: errando@astro.columbia.edu, E-mail: jholder@physics.udel.edu, E-mail: sfegan@llr.in2p3.fr [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Collaboration: VERITAS Collaboration; and others

    2013-10-20T23:59:59.000Z

    We report the detection of a new TeV gamma-ray source, VER J0521+211, based on observations made with the VERITAS imaging atmospheric Cherenkov Telescope Array. These observations were motivated by the discovery of a cluster of >30 GeV photons in the first year of Fermi Large Area Telescope observations. VER J0521+211 is relatively bright at TeV energies, with a mean photon flux of (1.93 ± 0.13{sub stat} ± 0.78{sub sys}) × 10{sup –11} cm{sup –2} s{sup –1} above 0.2 TeV during the period of the VERITAS observations. The source is strongly variable on a daily timescale across all wavebands, from optical to TeV, with a peak flux corresponding to ?0.3 times the steady Crab Nebula flux at TeV energies. Follow-up observations in the optical and X-ray bands classify the newly discovered TeV source as a BL Lac-type blazar with uncertain redshift, although recent measurements suggest z = 0.108. VER J0521+211 exhibits all the defining properties of blazars in radio, optical, X-ray, and gamma-ray wavelengths.

  16. Neutrino and cosmic-ray release from gamma-ray bursts: Time-dependent simulations

    SciTech Connect (OSTI)

    Asano, Katsuaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Mészáros, Peter, E-mail: asanok@icrr.u-tokyo.ac.jp, E-mail: nnp@psu.edu [Department of Astronomy and Astrophysics, Department of Physics, Center for Particle and Gravitational Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

    2014-04-10T23:59:59.000Z

    We revisit the neutrino and ultra-high-energy cosmic-ray (UHECR) production from gamma-ray bursts (GRBs) with time-dependent simulations for the proton-induced cascades. This method can generate self-consistent photon, neutrino, and escaped neutron spectra. To obtain the integrated background spectra, we take into account the distributions of the burst luminosity and pulse duration timescale. A benchmark case with standard GRB luminosity function, a bulk Lorentz factor ? = 300, and a proton to gamma-ray luminosity fraction f{sub p} = 10 is consistent with both the neutrino upper limits and the observed UHECR intensity at ?10{sup 20} eV, while requiring a different type of UHECR source at the ankle. For the benchmark case, the GRBs in the bright end of the luminosity function, which contribute most of the neutrinos, have their photon spectrum substantially distorted by secondary photons. Such bright GRBs are few in number, and reducing their f{sub p} eliminates the distortion and reduces the neutrino production. Even if we neglect the contribution of the brightest GRBs, the UHECR production rate at energies corresponding to the Greisen-Zatsepin-Kuzmin limit is almost unchanged. These nominal GRB models, especially with L {sub iso} ? 10{sup 53} erg s{sup –1}, appear to meet the current constraints as far as being candidate UHECR sources above the ankle energy.

  17. Milagro Constraints on Very High Energy Emission from Short Duration Gamma-Ray Bursts

    E-Print Network [OSTI]

    A. A. Abdo; B. T. Allen; D. Berley; E. Blaufuss; S. Casanova; B. L. Dingus; R. W. Ellsworth; M. M. Gonzalez; J. A. Goodman; E. Hays; C. M. Hoffman; B. E. Kolterman; C. P. Lansdell; J. T. Linnemann; J. E. McEnery; A. I. Mincer; P. Nemethy; D. Noyes; J. M. Ryan; F. W. Samuelson; P. M. Saz Parkinson; A. Shoup; G. Sinnis; A. J. Smith; G. W. Sullivan; V. Vasileiou; G. P. Walker; D. A. Williams; X. W. Xu; G. B. Yodh

    2007-05-10T23:59:59.000Z

    Recent rapid localizations of short, hard gamma-ray bursts (GRBs) by the Swift and HETE satellites have led to the observation of the first afterglows and the measurement of the first redshifts from this type of burst. Detection of >100 GeV counterparts would place powerful constraints on GRB mechanisms. Seventeen short duration (100 GeV counterparts to these GRBs and find no significant emission correlated with these bursts. Due to the absorption of high-energy gamma rays by the extragalactic background light (EBL), detections are only expected for redshifts less than ~0.5. While most long duration GRBs occur at redshifts higher than 0.5, the opposite is thought to be true of short GRBs. Lack of a detected VHE signal thus allows setting meaningful fluence limits. One GRB in the sample (050509b) has a likely association with a galaxy at a redshift of 0.225, while another (051103) has been tentatively linked to the nearby galaxy M81. Fluence limits are corrected for EBL absorption, either using the known measured redshift, or computing the corresponding absorption for a redshift of 0.1 and 0.5, as well as for the case of z=0.

  18. Combined Estimation of Hydrogeologic Conceptual Model and Parameter Uncertainty

    SciTech Connect (OSTI)

    Meyer, Philip D.; Ye, Ming; Neuman, Shlomo P.; Cantrell, Kirk J.

    2004-03-01T23:59:59.000Z

    The objective of the research described in this report is the development and application of a methodology for comprehensively assessing the hydrogeologic uncertainties involved in dose assessment, including uncertainties associated with conceptual models, parameters, and scenarios. This report describes and applies a statistical method to quantitatively estimate the combined uncertainty in model predictions arising from conceptual model and parameter uncertainties. The method relies on model averaging to combine the predictions of a set of alternative models. Implementation is driven by the available data. When there is minimal site-specific data the method can be carried out with prior parameter estimates based on generic data and subjective prior model probabilities. For sites with observations of system behavior (and optionally data characterizing model parameters), the method uses model calibration to update the prior parameter estimates and model probabilities based on the correspondence between model predictions and site observations. The set of model alternatives can contain both simplified and complex models, with the requirement that all models be based on the same set of data. The method was applied to the geostatistical modeling of air permeability at a fractured rock site. Seven alternative variogram models of log air permeability were considered to represent data from single-hole pneumatic injection tests in six boreholes at the site. Unbiased maximum likelihood estimates of variogram and drift parameters were obtained for each model. Standard information criteria provided an ambiguous ranking of the models, which would not justify selecting one of them and discarding all others as is commonly done in practice. Instead, some of the models were eliminated based on their negligibly small updated probabilities and the rest were used to project the measured log permeabilities by kriging onto a rock volume containing the six boreholes. These four projections, and associated kriging variances, were averaged using the posterior model probabilities as weights. Finally, cross-validation was conducted by eliminating from consideration all data from one borehole at a time, repeating the above process, and comparing the predictive capability of the model-averaged result with that of each individual model. Using two quantitative measures of comparison, the model-averaged result was superior to any individual geostatistical model of log permeability considered.

  19. Gravitational waves versus X-ray and gamma-ray emission in a short gamma-ray burst

    SciTech Connect (OSTI)

    Oliveira, F. G.; Rueda, Jorge A.; Ruffini, R., E-mail: fe.fisica@gmail.com, E-mail: jorge.rueda@icra.it, E-mail: ruffini@icra.it [Dipartimento di Fisica and ICRA, Sapienza Universitŕ di Roma, P.le Aldo Moro 5, I-00185 Rome (Italy)

    2014-06-01T23:59:59.000Z

    Recent progress in the understanding of the physical nature of neutron star equilibrium configurations and the first observational evidence of a genuinely short gamma-ray burst (GRB), GRB 090227B, allows us to give an estimate of the gravitational waves versus the X-ray and gamma-ray emission in a short GRB.

  20. Sandia National Laboratories: main parameter determining laminate...

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

    parameter determining laminate fatigue lifetime is the cumulative time under load New Material Tests Show Biaxial Laminate Creep Is Important for Large Wind-Turbine Blades On...

  1. Experimental Investigation of Effect of Injection Parameters...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Experimental Investigation of Effect of Injection Parameters, Compression Ratio and Ultra-cooled EGR on CI Engine Performance and Emissions Low temperature combustion,...

  2. ONE-PARAMETER CONTINUOUS FIELDS OF KIRCHBERG ...

    E-Print Network [OSTI]

    2008-09-05T23:59:59.000Z

    One-parameter separable unital continuous fields of Kirchberg algebras (nuclear purely infinite simple C*-algebras) with torsion free Ki-groups and trivial ...

  3. MAGNETIC STRUCTURES IN GAMMA-RAY BURST JETS PROBED BY GAMMA-RAY POLARIZATION

    SciTech Connect (OSTI)

    Yonetoku, Daisuke; Murakami, Toshio; Morihara, Yoshiyuki; Takahashi, Takuya; Wakashima, Yudai; Yonemochi, Hajime; Sakashita, Tomonori; Fujimoto, Hirofumi; Kodama, Yoshiki [College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192 (Japan); Gunji, Shuichi; Toukairin, Noriyuki [Department of Physics, Faculty of Science, Yamagata University, 1-4-12, Koshirakawa, Yamagata, Yamagata 990-8560 (Japan); Mihara, Tatehiro [Cosmic Radiation Laboratory, RIKEN, 2-1, Hirosawa, Wako City, Saitama 351-0198 (Japan); Toma, Kenji, E-mail: yonetoku@astro.s.kanazawa-u.ac.jp [Department of Earth and Space Science, Osaka University, Toyonaka 560-0043 (Japan)

    2012-10-10T23:59:59.000Z

    We report polarization measurements in two prompt emissions of gamma-ray bursts, GRB 110301A and GRB 110721A, observed with the gamma-ray burst polarimeter (GAP) on borad the IKAROS solar sail mission. We detected linear polarization signals from each burst with polarization degree of {Pi} = 70 {+-} 22% with statistical significance of 3.7{sigma} for GRB 110301A, and {Pi} = 84{sup +16}{sub -28}% with 3.3{sigma} confidence level for GRB 110721A. We did not detect any significant change of polarization angle. These two events had shorter durations and dimmer brightness compared with GRB 100826A, which showed a significant change of polarization angle, as reported in Yonetoku et al. Synchrotron emission model can be consistent with the data of the three GRBs, while the photospheric quasi-thermal emission model is not favored. We suggest that magnetic field structures in the emission region are globally ordered fields advected from the central engine.

  4. Measurement of 25Mg(p; gamma)26Al resonance strengths via gamma spectrometry

    E-Print Network [OSTI]

    A. Formicola; A. Best; G. Imbriani; M. Junker; D. Bemmerer; R. Bonetti; C. Broggini; A. Caciolli; F. Confortola; P. Corvisiero; H. Costantini; Z. Elekes; Zs Fulop; G. Gervino; A. Guglielmetti; Gy Gyurky; C. Gustavino; A. Lemut; B. Limata; M. Marta; C. Mazzocchi; R. Menegazzo; P. Prati; V. Roca; C. Rolfs; C. Rossi Alvarez; E. Somorjai; O. Straniero; F. Strieder; F. Terrasi; H. P. Trautvetter

    2007-10-23T23:59:59.000Z

    The COMPTEL instrument performed the first mapping of the 1.809 MeV photons in the Galaxy, triggering considerable interest in determing the sources of interstellar 26Al. The predicted 26Al is too low compared to the observation, for a better understanding more accurate rates for the 25Mg(p; gamma)26Al reaction are required. The 25Mg(p;gamma)26Al reaction has been investigated at the resonances at Er= 745; 418; 374; 304 keV at Ruhr-Universitat-Bochum using a Tandem accelerator and a 4piNaI detector. In addition the resonance at Er = 189 keV has been measured deep underground laboratory at Laboratori Nazionali del Gran Sasso, exploiting the strong suppression of cosmic background. This low resonance has been studied with the 400 kV LUNA accelerator and a HPGe detector. The preliminary results of the resonance strengths will be reported.

  5. Measurement of 25Mg(p; gamma)26Al resonance strengths via gamma spectrometry

    E-Print Network [OSTI]

    Formicola, A; Imbriani, G; Junker, M; Bemmerer, D; Bonetti, R; Broggini, C; Caciolli, A; Confortola, F; Corvisiero, P; Costantini, H; Elekes, Z; Fülöp, Z; Gervino, G; Guglielmetti, A; Gyurky, Gy; Gustavino, C; Lemut, A; Limata, B; Marta, M; Mazzocchi, C; Menegazzo, R; Prati, P; Roca, V; Rolfs, C; Alvarez, C Rossi; Somorjai, E; Straniero, O; Strieder, F; Terrasi, F; Trautvetter, H P

    2007-01-01T23:59:59.000Z

    The COMPTEL instrument performed the first mapping of the 1.809 MeV photons in the Galaxy, triggering considerable interest in determing the sources of interstellar 26Al. The predicted 26Al is too low compared to the observation, for a better understanding more accurate rates for the 25Mg(p; gamma)26Al reaction are required. The 25Mg(p;gamma)26Al reaction has been investigated at the resonances at Er= 745; 418; 374; 304 keV at Ruhr-Universitat-Bochum using a Tandem accelerator and a 4piNaI detector. In addition the resonance at Er = 189 keV has been measured deep underground laboratory at Laboratori Nazionali del Gran Sasso, exploiting the strong suppression of cosmic background. This low resonance has been studied with the 400 kV LUNA accelerator and a HPGe detector. The preliminary results of the resonance strengths will be reported.

  6. Magnetic Structures in Gamma-Ray Burst Jets Probed by Gamma-Ray Polarization

    E-Print Network [OSTI]

    Daisuke Yonetoku; Toshio Murakami; Shuichi Gunji; Tatehiro Mihara; Kenji Toma; Yoshiyuki Morihara; Takuya Takahashi; Yudai Wakashima; Hajime Yonemochi; Tomonori Sakashita; Noriyuki Toukairin; Hirofumi Fujimoto; Yoshiki Kodama

    2012-08-27T23:59:59.000Z

    We report polarization measurements in two prompt emissions of gamma-ray bursts, GRB 110301A and GRB 110721A, observed with the Gamma-ray burst polarimeter (GAP) aboard IKAROS solar sail mission. We detected linear polarization signals from each burst with polarization degree of $\\Pi = 70 \\pm 22$% with statistical significance of $3.7 \\sigma$ for GRB 110301A, and $\\Pi = 84^{+16}_{-28}$% with $3.3 \\sigma$ confidence level for GRB 110721A. We did not detect any significant change of polarization angle. These two events had shorter durations and dimmer brightness compared with GRB 100826A, which showed a significant change of polarization angle, as reported in Yonetoku et al. (2011). Synchrotron emission model can be consistent with all the data of the three GRBs, while photospheric quasi-thermal emission model is not favorable. We suggest that magnetic field structures in the emission region are globally-ordered fields advected from the central engine.

  7. Gamma-ray blind beta particle probe

    DOE Patents [OSTI]

    Weisenberger, Andrew G. (Grafton, VA)

    2001-01-01T23:59:59.000Z

    An intra-operative beta particle probe is provided by placing a suitable photomultiplier tube (PMT), micro channel plate (MCP) or other electron multiplier device within a vacuum housing equipped with: 1) an appropriate beta particle permeable window; and 2) electron detection circuitry. Beta particles emitted in the immediate vicinity of the probe window will be received by the electron multiplier device and amplified to produce a detectable signal. Such a device is useful as a gamma insensitive, intra-operative, beta particle probe in surgeries where the patient has been injected with a beta emitting radiopharmaceutical. The method of use of such a device is also described, as is a position sensitive such device.

  8. Neutrino oscillations and gamma-ray bursts

    E-Print Network [OSTI]

    W. Kluzniak

    1998-07-22T23:59:59.000Z

    If the ordinary neutrinos oscillate into a sterile flavor in a manner consistent with the Super-Kamiokande data on the zenith-angle dependence of atmospheric mu-neutrino flux, an energy sufficient to power a typical cosmic gamma-ray burst (GRB) (about 10^{52} erg) can be carried by sterile neutrinos away from the source and deposited in a region relatively free of baryons. Hence, ultra-relativistic bulk motion (required by the theory of and observations of GRBs and their afterglows) can easily be achieved in the vicinity of plausible sources of GRBs. Oscillations between sterile and ordinary neutrinos would thus provide a solution to the ``baryon-loading problem'' in the theory of GRBs.

  9. Constraining Lorentz violations with Gamma Ray Bursts

    E-Print Network [OSTI]

    Maria Rodriguez Martinez; Tsvi Piran

    2006-05-17T23:59:59.000Z

    Gamma ray bursts are excellent candidates to constrain physical models which break Lorentz symmetry. We consider deformed dispersion relations which break the boost invariance and lead to an energy-dependent speed of light. In these models, simultaneously emitted photons from cosmological sources reach Earth with a spectral time delay that depends on the symmetry breaking scale. We estimate the possible bounds which can be obtained by comparing the spectral time delays with the time resolution of available telescopes. We discuss the best strategy to reach the strongest bounds. We compute the probability of detecting bursts that improve the current bounds. The results are encouraging. Depending on the model, it is possible to build a detector that within several years will improve the present limits of 0.015 m_pl.

  10. Short Gamma-Ray Bursts Are Different

    E-Print Network [OSTI]

    J. P. Norris; J. D. Scargle; J. T. Bonnell

    2001-05-07T23:59:59.000Z

    We analyze BATSE time-tagged event (TTE) data for short gamma-ray bursts (T90 duration burst. Performing the cross-correlation between two energy bands, we measure an average lag ~ 20-40 x shorter than for long bursts, and a lag distribution close to symmetric about zero - unlike long bursts. Using a "Bayesian Block" method to identify significantly distinct pulse peaks, we find an order of magnitude fewer pulses than found in studies of long bursts. The disparity in lag magnitude is discontinuous across the ~ 2-s valley between long and short bursts. Thus, short bursts do not appear to be representable as a continuation of long bursts' temporal characteristics.

  11. Super Luminous Supernova and Gamma Ray Bursts

    E-Print Network [OSTI]

    Shlomo Dado; Arnon Dar

    2012-11-08T23:59:59.000Z

    We use a simple analytical model to derive a closed form expression for the bolometric light-curve of super-luminus supernovae (SLSNe) powered by a plastic collision between the fast ejecta from core collapse supernovae (SNe) of types Ib/c and IIn and slower massive circum-stellar shells, ejected during the late stage of the life of their progenitor stars preceding the SN explosion. We demonstrate that this expression reproduces well the bolometric luminosity of SLSNe with and without an observed gamma ray burst (GRB), and requires only a modest amount ($M < 0.1\\,M_\\odot$) of radioactive $^{56}$Ni synthesized in the SN explosion in order to explain their late-time luminosity. Long duration GRBs can be produced by ordinary SNe of type Ic rather than by 'hypernovae' - a subclass of superenergetic SNeIb/c.

  12. Data Mining in Gamma Astrophysics Experiments

    E-Print Network [OSTI]

    M. Frailis; A. De Angelis; V. Roberto

    2005-03-24T23:59:59.000Z

    Data mining techniques, including clustering and classification tasks, for the automatic information extraction from large datasets are increasingly demanded in several scientific fields. In particular, in the astrophysical field, large archives and digital sky surveys with dimensions of 10E12 bytes currently exist, while in the near future they will reach sizes of the order of 10E15. In this work we propose a multidimensional indexing method to efficiently query and mine large astrophysical datasets. A novelty detection algorithm, based on the Support Vector Clustering and using density and neighborhood information stored in the index structure, is proposed to find regions of interest in data characterized by isotropic noise. We show an application of this method for the detection of point sources from a gamma-ray photon list.

  13. Search for Gamma Ray Bursts at Chacaltaya

    E-Print Network [OSTI]

    Silvia Vernetto; for the INCA Collaboration

    2000-11-13T23:59:59.000Z

    A search for Gamma Ray Bursts in the GeV-TeV energy range has been performed by INCA, an air shower array working at 5200 m of altitude at the Chacaltaya Laboratory (Bolivia). The altitude of the detector and the use of the "single particle technique" allows to lower the energy threshold up to few GeVs. No significant signals are observed during the occurrence of 125 GRBs detected by BATSE, and the obtained upper limits on the energy fluence in the interval 1-1000(100) GeV range from 3.2(8.6) 10^-5 to 2.6(7.0) 10^-2 erg/cm^2 depending on the zenith angle of the events. These limits, thanks to the extreme altitude of INCA, are the lowest ever obtained in the sub-TeV energy region by a ground based esperiment.

  14. Measurement of the W Gamma --> mu nu gamma Cross-Section, Limits on Anomalous Trilinear Vector Boson Couplings, and the Radiation Amplitude Zero in p anti-p Collisions at s**(1/2) = 1.96 TeV

    SciTech Connect (OSTI)

    Askew, Andrew Warren

    2004-11-01T23:59:59.000Z

    This thesis details the measurement of the p{bar p} {yields} W{gamma} + X {yields} {mu}{nu}{gamma} + X cross section at {radical}s = 1.96 TeV using the D0 detector at Fermilab, in 134.5 pb{sup -1} of integrated luminosity. From the photon E{sub T} spectrum limits on anomalous couplings of the photon to the W are obtained. At 95% confidence level, limits of -1.05 < {Delta}{kappa} < 1.04 for {lambda} = 0 and -0.28 < {lambda} < 0.27 for {Delta}{kappa} = 0 are obtained on the anomalous coupling parameters. The charge signed rapidity difference from the data is displayed, and its significance discussed.

  15. Gamma Knife Radiosurgery for the Treatment of Cystic Cerebral Metastases

    SciTech Connect (OSTI)

    Ebinu, Julius O.; Lwu, Shelly; Monsalves, Eric; Arayee, Mandana [Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, Toronto, Ontario (Canada)] [Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, Toronto, Ontario (Canada); Chung, Caroline; Laperriere, Normand J. [Department of Radiation Oncology, Princess Margaret Hospital, University Health Network, University of Toronto, Toronto, Ontario (Canada)] [Department of Radiation Oncology, Princess Margaret Hospital, University Health Network, University of Toronto, Toronto, Ontario (Canada); Kulkarni, Abhaya V.; Goetz, Pablo [Division of Neurosurgery, Department of Surgery, The Hospital for Sick Children, University of Toronto, Toronto, Ontario (Canada)] [Division of Neurosurgery, Department of Surgery, The Hospital for Sick Children, University of Toronto, Toronto, Ontario (Canada); Zadeh, Gelareh, E-mail: gelareh.zadeh@uhn.on.ca [Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, Toronto, Ontario (Canada)] [Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, Toronto, Ontario (Canada)

    2013-03-01T23:59:59.000Z

    Purpose: To assess the role of Gamma Knife radiosurgery (GKRS) in the treatment of nonsurgical cystic brain metastasis, and to determine predictors of response to GKRS. Methods: We reviewed a prospectively maintained database of brain metastases patients treated at our institution between 2006 and 2010. All lesions with a cystic component were identified, and volumetric analysis was done to measure percentage of cystic volume on day of treatment and consecutive follow-up MRI scans. Clinical, radiologic, and dosimetry parameters were reviewed to establish the overall response of cystic metastases to GKRS as well as identify potential predictive factors of response. Results: A total of 111 lesions in 73 patients were analyzed; 57% of lesions received prior whole-brain radiation therapy (WBRT). Lung carcinoma was the primary cancer in 51% of patients, 10% breast, 10% colorectal, 4% melanoma, and 26% other. Fifty-seven percent of the patients were recursive partitioning analysis class 1, the remainder class 2. Mean target volume was 3.3 mL (range, 0.1-23 mL). Median prescription dose was 21 Gy (range, 15-24 Gy). Local control rates were 91%, 63%, and 37% at 6, 12, and 18 months, respectively. Local control was improved in lung primary and worse in patients with prior WBRT (univariate). Only lung primary predicted local control in multivariate analysis, whereas age and tumor volume did not. Lesions with a large cystic component did not show a poorer response compared with those with a small cystic component. Conclusions: This study supports the use of GKRS in the management of nonsurgical cystic metastases, despite a traditionally perceived poorer response. Our local control rates are comparable to a matched cohort of noncystic brain metastases, and therefore the presence of a large cystic component should not deter the use of GKRS. Predictors of response included tumor subtype. Prior WBRT decreased effectiveness of SRS for local control rates.

  16. High Energy Gamma-Ray Emission from Gamma-Ray Bursts - Before GLAST

    SciTech Connect (OSTI)

    Fan, Yi-Zhong; Piran, Tsvi

    2011-11-29T23:59:59.000Z

    Gamma-ray bursts (GRBs) are short and intense emission of soft {gamma}-rays, which have fascinated astronomers and astrophysicists since their unexpected discovery in 1960s. The X-ray/optical/radio afterglow observations confirm the cosmological origin of GRBs, support the fireball model, and imply a long-activity of the central engine. The high-energy {gamma}-ray emission (> 20 MeV) from GRBs is particularly important because they shed some lights on the radiation mechanisms and can help us to constrain the physical processes giving rise to the early afterglows. In this work, we review observational and theoretical studies of the high-energy emission from GRBs. Special attention is given to the expected high-energy emission signatures accompanying the canonical early-time X-ray afterglow that was observed by the Swift X-ray Telescope. We also discuss the detection prospect of the upcoming GLAST satellite and the current ground-based Cerenkov detectors.

  17. Constraints on Very High Energy gamma-ray emission from Gamma-Ray Bursts

    E-Print Network [OSTI]

    Atkins, R; Berley, D; Blaufuss, E; Coyne, D G; De Young, T R; Dingus, B L; Dorfan, D E; Ellsworth, R W; Fleysher, L; Fleysher, R; González, M M; Goodman, J A; Hays, E; Hoffman, C M; Kelley, L A; Lansdell, C P; Linnemann, J T; McEnery, J E; Mincer, A I; Morales, M F; Némethy, P; Noyes, D; Ryan, J M; Samuelson, F W; Parkinson, P M S; Shoup, A; Sinnis, G; Smith, A J; Sullivan, G W; Williams, D A; Wilson, M E; Xu, X W; Yodh, G B

    2005-01-01T23:59:59.000Z

    The Milagro gamma-ray observatory employs a water Cherenkov detector to observe extensive air showers produced by high energy particles interacting in the Earth's atmosphere. Milagro has a wide field of view and high duty cycle, monitoring the northern sky almost continuously in the 100 GeV to 100 TeV energy range. Milagro is, thus, uniquely capable of searching for very high-energy emission from gamma-ray bursts (GRBs) during the prompt emission phase. Detection of >100 GeV counterparts would place powerful constraints on GRB mechanisms. Twenty-five satellite-triggered GRBs occurred within the field of view of Milagro between January 2000 and December 2001. We have searched for counterparts to these GRBs and found no significant emission from any of the burst positions. Due to the absorption of high-energy gamma rays by the extragalactic background light, detections are only expected to be possible for redshifts less than ~0.5. Three of the GRBs studied have measured redshifts. GRB 010921 has a redshift low ...

  18. Constraints on Very High Energy gamma-ray emission from Gamma-Ray Bursts

    E-Print Network [OSTI]

    R. Atkins; W. Benbow; D. Berley; E. Blaufuss; D. G. Coyne; T. DeYoung; B. L. Dingus; D. E. Dorfan; R. W. Ellsworth; L. Fleysher; R. Fleysher; M. M. Gonzalez; J. A. Goodman; E. Hays; C. M. Hoffman; L. A. Kelley; C. P. Lansdell; J. T. Linnemann; J. E. McEnery; A. I. Mincer; M. F. Morales; P. Nemethy; D. Noyes; J. M. Ryan; F. W. Samuelson; P. M. Saz Parkinson; A. Shoup; G. Sinnis; A. J. Smith; G. W. Sullivan; D. A. Williams; M. E. Wilson; X. W. Xu; G. B. Yodh

    2005-03-11T23:59:59.000Z

    The Milagro gamma-ray observatory employs a water Cherenkov detector to observe extensive air showers produced by high energy particles interacting in the Earth's atmosphere. Milagro has a wide field of view and high duty cycle, monitoring the northern sky almost continuously in the 100 GeV to 100 TeV energy range. Milagro is, thus, uniquely capable of searching for very high-energy emission from gamma-ray bursts (GRBs) during the prompt emission phase. Detection of >100 GeV counterparts would place powerful constraints on GRB mechanisms. Twenty-five satellite-triggered GRBs occurred within the field of view of Milagro between January 2000 and December 2001. We have searched for counterparts to these GRBs and found no significant emission from any of the burst positions. Due to the absorption of high-energy gamma rays by the extragalactic background light, detections are only expected to be possible for redshifts less than ~0.5. Three of the GRBs studied have measured redshifts. GRB 010921 has a redshift low enough (0.45) to allow an upper limit on the fluence to place an observational constraint on potential GRB models.

  19. On The Origin Of High Energy Correlations in Gamma-ray Bursts

    SciTech Connect (OSTI)

    Kocevski, Daniel

    2012-04-03T23:59:59.000Z

    I investigate the origin of the observed correlation between a gamma-ray burst's {nu}F{sub {nu}} spectral peak E{sub pk} and its isotropic equivalent energy E{sub iso} through the use of a population synthesis code to model the prompt gamma-ray emission from GRBs. By using prescriptions for the distribution of prompt spectral parameters as well as the population's luminosity function and co-moving rate density, I generate a simulated population of GRBs and examine how bursts of varying spectral properties and redshift would appear to a gamma-ray detector here on Earth. I find that a strong observed correlation can be produced between the source frame Epk and Eiso for the detected population despite the existence of only a weak and broad correlation in the original simulated population. The energy dependance of a gamma-ray detector's flux-limited detection threshold acts to produce a correlation between the source frame E{sub pk} and E{sub iso} for low luminosity GRBs, producing the left boundary of the observed correlation. Conversely, very luminous GRBs are found at higher redshifts than their low luminosity counterparts due to the standard Malquest bias, causing bursts in the low E{sub pk}, high E{sub iso} regime to go undetected because their E{sub pk} values would be redshifted to energies at which most gamma-ray detectors become less sensitive. I argue that it is this previously unexamined effect which produces the right boundary of the observed correlation. Therefore, the origin of the observed correlation is a complex combination of the instrument's detection threshold, the intrinsic cutoff in the GRB luminosity function, and the broad range of redshifts over which GRBs are detected. Although the GRB model presented here is a very simplified representation of the complex nature of GRBs, these simulations serve to demonstrate how selection effects caused by a combination of instrumental sensitivity and the cosmological nature of an astrophysical population can act to produce an artificially strong correlation between observed properties.

  20. ON THE ORIGIN OF HIGH-ENERGY CORRELATIONS IN GAMMA-RAY BURSTS

    SciTech Connect (OSTI)

    Kocevski, Daniel [Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, 2575 Sand Hill Road M/S 29, Menlo Park, CA 94025 (United States)

    2012-03-10T23:59:59.000Z

    I investigate the origin of the observed correlation between a gamma-ray burst's (GRB's) {nu}F{sub {nu}} spectral peak E{sub pk} and its isotropic equivalent energy E{sub iso} through the use of a population synthesis code to model the prompt gamma-ray emission from GRBs. By using prescriptions for the distribution of prompt spectral parameters as well as the population's luminosity function and comoving rate density, I generate a simulated population of GRBs and examine how bursts of varying spectral properties and redshift would appear to a gamma-ray detector here on Earth. I find that a strong observed correlation can be produced between the source frame E{sub pk} and E{sub iso} for the detected population despite the existence of only a weak and broad correlation in the original simulated population. The energy dependance of a gamma-ray detector's flux-limited detection threshold acts to produce a correlation between the source frame E{sub pk} and E{sub iso} for low-luminosity GRBs, producing the left boundary of the observed correlation. Conversely, very luminous GRBs are found at higher redshifts than their low-luminosity counterparts due to the standard Malquest bias, causing bursts in the low E{sub pk}, high E{sub iso} regime to go undetected because their E{sub pk} values would be redshifted to energies at which most gamma-ray detectors become less sensitive. I argue that it is this previously unexamined effect which produces the right boundary of the observed correlation. Therefore, the origin of the observed correlation is a complex combination of the instrument's detection threshold, the intrinsic cutoff in the GRB luminosity function, and the broad range of redshifts over which GRBs are detected. Although the GRB model presented here is a very simplified representation of the complex nature of GRBs, these simulations serve to demonstrate how selection effects caused by a combination of instrumental sensitivity and the cosmological nature of an astrophysical population can act to produce an artificially strong correlation between observed properties.

  1. Exceptional Laguerre and Jacobi polynomials and the corresponding potentials through Darboux-Crum Transformations

    E-Print Network [OSTI]

    Ryu Sasaki; Satoshi Tsujimoto; Alexei Zhedanov

    2010-04-27T23:59:59.000Z

    Simple derivation is presented of the four families of infinitely many shape invariant Hamiltonians corresponding to the exceptional Laguerre and Jacobi polynomials. Darboux-Crum transformations are applied to connect the well-known shape invariant Hamiltonians of the radial oscillator and the Darboux-P\\"oschl-Teller potential to the shape invariant potentials of Odake-Sasaki. Dutta and Roy derived the two lowest members of the exceptional Laguerre polynomials by this method. The method is expanded to its full generality and many other ramifications, including the aspects of generalised Bochner problem and the bispectral property of the exceptional orthogonal polynomials, are discussed.

  2. SC Correspondence Control Center (SC CCC) | U.S. DOE Office of Science (SC)

    Office of Science (SC) Website

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron4(SC) Mapping the ImpactSC Correspondence Control Center (SC CCC)

  3. Application of Artificial Neural Network to Search for Gravitational-Wave Signals Associated with Short Gamma-Ray Bursts

    E-Print Network [OSTI]

    Kyungmin Kim; Ian W. Harry; Kari A. Hodge; Young-Min Kim; Chang-Hwan Lee; Hyun Kyu Lee; John J. Oh; Sang Hoon Oh; Edwin J. Son

    2015-03-03T23:59:59.000Z

    We apply a machine learning algorithm, the artificial neural network, to the search for gravitational-wave signals associated with short gamma-ray bursts. The multi-dimensional samples consisting of data corresponding to the statistical and physical quantities from the coherent search pipeline are fed into the artificial neural network to distinguish simulated gravitational-wave signals from background noise artifacts. Our result shows that the data classification efficiency at a fixed false alarm probability is improved by the artificial neural network in comparison to the conventional detection statistic. Therefore, this algorithm increases the distance at which a gravitational-wave signal could be observed in coincidence with a gamma-ray burst. In order to demonstrate the performance, we also evaluate a few seconds of gravitational-wave data segment using the trained networks and obtain the false alarm probability. We suggest that the artificial neural network can be a complementary method to the conventional detection statistic for identifying gravitational-wave signals related to the short gamma-ray bursts.

  4. Additional resonant contribution to the potential model for the 12C(alpha,gamma)16O reaction

    E-Print Network [OSTI]

    M. Katsuma

    2014-04-15T23:59:59.000Z

    The additional resonant contribution to the potential model is examined in $\\alpha$+$^{12}$C elastic scattering and the low-energy $^{12}$C($\\alpha$,$\\gamma$)$^{16}$O reaction. The excitation function of elastic scattering below $E_{c.m.}= 5$ MeV seems to be reproduced by the potential model satisfactorily, and it is not profoundly disturbed by the additional resonances. The weak coupling is good enough to describe the $^{16}$O structure in the vicinity of the $\\alpha$-particle threshold, especially below $E_{c.m.}= 8$ MeV, corresponding to the excitation energy $E_x \\approx 15$ MeV. The additional resonances give the complement of the astrophysical $S$-factors from the simple potential model. The $S$-factor of $^{12}$C($\\alpha$,$\\gamma$)$^{16}$O at $E_{c.m.}=300$ keV is dominated by the $E$2 transition, which is enhanced by the subthreshold 2$^+_1$ state at $E_x= 6.92$ MeV. The contribution from the subthreshold 1$^-_1$ state at $E_x= 7.12$ MeV is predicted to be small. The additional resonances do not give the large contribution to the thermonuclear reaction rates of $^{12}$C($\\alpha$,$\\gamma$)$^{16}$O at helium burning temperatures.

  5. Extragalactic database. VII Reduction of astrophysical parameters

    E-Print Network [OSTI]

    G. Paturel; H. Andernach; L. Bottinelli; H. Di Nella; N. Durand; R. Garnier; L. Gouguenheim; P. Lanoix; M. C. Marthinet; C. Petit; J. Rousseau; G. Theureau; I. Vauglin

    1998-06-10T23:59:59.000Z

    The Lyon-Meudon Extragalactic database (LEDA) gives a free access to the main astrophysical parameters for more than 100,000 galaxies. The most common names are compiled allowing users to recover quickly any galaxy. All these measured astrophysical parameters are first reduced to a common system according to well defined reduction formulae leading to mean homogeneized parameters. Further, these parameters are also transformed into corrected parameters from widely accepted models. For instance, raw 21-cm line widths are transformed into mean standard widths after correction for instrumental effect and then into maximum velocity rotation properly corrected for inclination and non-circular velocity. This paper presents the reduction formulae for each parameter: coordinates, morphological type and luminosity class, diameter and axis ratio, apparent magnitude (UBV, IR, HI) and colors, maximum velocity rotation and central velocity dispersion, radial velocity, mean surface brightness, distance modulus and absolute magnitude, and group membership. For each of these parameters intermediate quantities are given: galactic extinction, inclination, K-correction etc.. All these parameters are available from direct connexion to LEDA (telnet lmc.univ-lyon1.fr, login: leda, no passwd OR http://www-obs.univ-lyon1.fr/leda ) and distributed on a standard CD-ROM (PGC-ROM 1996) by the Observatoire de Lyon via the CNRS (mail to petit@obs.univ-lyon1.fr).

  6. The Gamma-ray Albedo of the Moon

    SciTech Connect (OSTI)

    Moskalenko, Igor V.; /Stanford U., HEPL; Porter, Troy A.; /UC, Santa Cruz

    2007-09-28T23:59:59.000Z

    We use the GEANT4 Monte Carlo framework to calculate the {gamma}-ray albedo of the Moon due to interactions of cosmic ray (CR) nuclei with moon rock. Our calculation of the albedo spectrum agrees with the EGRET data. We show that the spectrum of {gamma}-rays from the Moon is very steep with an effective cutoff around 3-4 GeV (600 MeV for the inner part of the Moon disk) and exhibits a narrow pion-decay line at 67.5 MeV, perhaps unique in astrophysics. Apart from other astrophysical sources, the albedo spectrum of the Moon is well understood, including its absolute normalization; this makes it a useful 'standard candle' for {gamma}-ray telescopes. The steep albedo spectrum also provides a unique opportunity for energy calibration of {gamma}-ray telescopes, such as the forthcoming Gamma Ray Large Area Space Telescope (GLAST). Since the albedo flux depends on the incident CR spectrum which changes over the solar cycle, it is possible to monitor the CR spectrum using the albedo {gamma}-ray flux. Simultaneous measurements of CR proton and helium spectra by the Payload for Antimatter-Matter Exploration and Light-nuclei Astrophysics (PAMELA), and observations of the albedo {gamma}-rays by the GLAST Large Area Telescope (LAT), can be used to test the model predictions and will enable the LAT to monitor the CR spectrum near the Earth beyond the lifetime of the PAMELA.

  7. Light-Front Quantization Approach to the Gauge Gravity Correspondence and Hadron Spectroscopy

    SciTech Connect (OSTI)

    de Teramond, Guy F.; /Costa Rica U.; Brodsky, Stanley J.; /SLAC

    2010-05-26T23:59:59.000Z

    We find a correspondence between semiclassical QCD quantized on the light-front and a dual gravity model in anti-de Sitter (AdS) space, thus providing an initial approximation to QCD in its strongly coupled regime. This correspondence - light-front holography - leads to a light-front Hamiltonian and relativistic bound-state wave equations that are functions of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within hadrons at equal lightfront time. The eigenvalues of the resulting light-front Schrodinger and Dirac equations are consistent with the observed light meson and baryon spectrum, and the eigenmodes provide the light-front wavefunctions, the probability amplitudes describing the dynamics of the hadronic constituents. The light-front equations of motion, which are dual to an effective classical gravity theory, possess remarkable algebraic and integrability properties which are dictated by the underlying conformal properties of the theory. We extend the algebraic construction to include a confining potential while preserving the integrability of the mesonic and baryonic bound-state equations.

  8. Light-Front Quantization Approach to the Gauge-Gravity Correspondence and Hadron Spectroscopy

    SciTech Connect (OSTI)

    Teramond, Guy F. de [Universidad de Costa Rica, San Jose (Costa Rica); Brodsky, Stanley J. [SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94309 (United States)

    2010-08-05T23:59:59.000Z

    We find a correspondence between semiclassical QCD quantized on the light-front and a dual gravity model in anti--de Sitter (AdS) space, thus providing an initial approximation to QCD in its strongly coupled regime. This correspondence--light-front holography--leads to a light-front Hamiltonian and relativistic bound-state wave equations that are functions of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within hadrons at equal light-front time. The eigenvalues of the resulting light-front Schroedinger and Dirac equations are consistent with the observed light meson and baryon spectrum, and the eigenmodes provide the light-front wavefunctions, the probability amplitudes describing the dynamics of the hadronic constituents. The light-front equations of motion, which are dual to an effective classical gravity theory, possess remarkable algebraic and integrability properties which are dictated by the underlying conformal properties of the theory. We extend the algebraic construction to include a confining potential while preserving the integrability of the mesonic and baryonic bound-state equations.

  9. Analysis of neutron scattering data: Visualization and parameter estimation

    SciTech Connect (OSTI)

    Beauchamp, J.J.; Fedorov, V.; Hamilton, W.A.; Yethiraj, M.

    1998-09-01T23:59:59.000Z

    Traditionally, small-angle neutron and x-ray scattering (SANS and SAXS) data analysis requires measurements of the signal and corrections due to the empty sample container, detector efficiency and time-dependent background. These corrections are then made on a pixel-by-pixel basis and estimates of relevant parameters (e.g., the radius of gyration) are made using the corrected data. This study was carried out in order to determine whether treatment of the detector efficiency and empty sample cell in a more statistically sound way would significantly reduce the uncertainties in the parameter estimators. Elements of experiment design are shortly discussed in this paper. For instance, we studied the way the time for a measurement should be optimally divided between the counting for signal, background and detector efficiency. In Section 2 we introduce the commonly accepted models for small-angle neutron and x-scattering and confine ourselves to the Guinier and Rayleigh models and their minor generalizations. The traditional approaches of data analysis are discussed only to the extent necessary to allow their comparison with the proposed techniques. Section 3 describes the main stages of the proposed method: visual data exploration, fitting the detector sensitivity function, and fitting a compound model. This model includes three additive terms describing scattering by the sampler, scattering with an empty container and a background noise. We compare a few alternatives for the first term by applying various scatter plots and computing sums of standardized squared residuals. Possible corrections due to smearing effects and randomness of estimated parameters are also shortly discussed. In Section 4 the robustness of the estimators with respect to low and upper bounds imposed on the momentum value is discussed. We show that for the available data set the most accurate and stable estimates are generated by models containing double terms either of Guinier's or Rayleigh's type. The optimal partitioning of the total experimental time between measuring various signals is discussed in Section 5. We applied a straightforward optimization instead of some special experimental techniques because of the numerical simplicity of the corresponding problem. As a criterion of optimality we selected the variance of the gyration radius maximum likelihood estimator. The statistical background of the proposed approach is given in the appendix. The properties of the maximum likelihood estimators and the corresponding iterated estimator together with its possible numerical realization are presented in subsection A.1. In subsection A.2 we prove that the use of a compound model leads to more efficient estimators than a stage-wise analysis of different components entering that model.

  10. Correspondence: Email: korpela@ssl.berkeley.edu; Telephone: (510) 643-6538; URL: http://setiathome.ssl.berkeley.edu/~korpela

    E-Print Network [OSTI]

    Korpela, Eric J.

    ___________________ Correspondence: Email: korpela@ssl.berkeley.edu; Telephone: (510) 643-6538; URL: http://setiathome.ssl.berkeley.edu/~korpela The SPEAR Science Payload Eric J. Korpelaa , Jerry

  11. Raman and AFM study of gamma irradiated plastic bottle sheets

    SciTech Connect (OSTI)

    Ali, Yasir; Kumar, Vijay; Dhaliwal, A. S. [Department of Physics, Sant Longowal Institute of Engineering and Technology Longowal, Punjab-148106 (India); Sonkawade, R. G. [School of Physical Sciences, Babasaheb Bhimrao Ambedkar University, Lucknow-226025 (India)

    2013-02-05T23:59:59.000Z

    In this investigation, the effects of gamma irradiation on the structural properties of plastic bottle sheet are studied. The Plastic sheets were exposed with 1.25MeV {sup 60}Co gamma rays source at various dose levels within the range from 0-670 kGy. The induced modifications were followed by micro-Raman and atomic force microscopy (AFM). The Raman spectrum shows the decrease in Raman intensity and formation of unsaturated bonds with an increase in the gamma dose. AFM image displays rough surface morphology after irradiation. The detailed Raman analysis of plastic bottle sheets is presented here, and the results are correlated with the AFM observations.

  12. Gamma Ray Burst Constraints on Ultraviolet Lorentz Invariance Violation

    E-Print Network [OSTI]

    Tina Kahniashvili; Grigol Gogoberidze; Bharat Ratra

    2006-10-20T23:59:59.000Z

    We present a unified general formalism for ultraviolet Lorentz invariance violation (LV) testing through electromagnetic wave propagation, based on both dispersion and rotation measure data. This allows for a direct comparison of the efficacy of different data to constrain LV. As an example we study the signature of LV on the rotation of the polarization plane of $\\gamma$-rays from gamma ray bursts in a LV model. Here $\\gamma$-ray polarization data can provide a strong constraint on LV, 13 orders of magnitude more restrictive than a potential constraint from the rotation of the cosmic microwave background polarization proposed by Gamboa, L\\'{o}pez-Sarri\\'{o}n, and Polychronakos (2006).

  13. GRABGAM Analysis of Ultra-Low-Level HPGe Gamma Spectra

    SciTech Connect (OSTI)

    Winn, W.G.

    1999-07-28T23:59:59.000Z

    The GRABGAM code has been used successfully for ultra-low level HPGe gamma spectrometry analysis since its development in 1985 at Savannah River Technology Center (SRTC). Although numerous gamma analysis codes existed at that time, reviews of institutional and commercial codes indicated that none addressed all features that were desired by SRTC. Furthermore, it was recognized that development of an in-house code would better facilitate future evolution of the code to address SRTC needs based on experience with low-level spectra. GRABGAM derives its name from Gamma Ray Analysis BASIC Generated At MCA/PC.

  14. Hafnium Resonance Parameter Analysis Using Neutron Capture and Transmission Experiments

    SciTech Connect (OSTI)

    Trbovich, M J; Barry, D P; Slovacek, R E; Danon, Y; Block, R C; Francis, N C; Lubert, M; Burke, J A; Drindak, N J; Lienweber, G; Ballad, R

    2007-02-06T23:59:59.000Z

    The focus of this work is to determine the resonance parameters for stable hafnium isotopes in the 0.005 - 200 eV region, with special emphasis on the overlapping {sup 176}Hf and {sup 178}Hf resonances near 8 eV. Accurate hafnium cross sections and resonance parameters are needed in order to quantify the effects of hafnium found in zirconium, a metal commonly used in reactors. The accuracy of the cross sections and the corresponding resonance parameters used in current nuclear analysis tools are rapidly becoming the limiting factor in reducing the overall uncertainty on reactor physics calculations. Experiments measuring neutron capture and transmission are routinely performed at the Rensselaer Polytechnic Institute (RPI) LINAC using the time-of flight technique. {sup 6}Li glass scintillation detectors were used for transmission experiments at flight path lengths of 15 and 25 m, respectively. Capture experiments were performed using a sixteen section NaI multiplicity detector at a flight path length of 25 m. These experiments utilized several thicknesses of metallic and isotope-enriched liquid Hf samples. The liquid Hf samples were designed to provide information on the {sup 176}Hf and {sup 178}Hf contributions to the 8 eV doublet without saturation. Data analyses were performed using the R-matrix Bayesian code SAMMY. A combined capture and transmission data analysis yielded resonance parameters for all hafnium isotopes from 0.005 - 200 eV. Additionally, resonance integrals were calculated, along with errors for each hafnium isotope, using the NJOY and INTER codes. The isotopic resonance integrals calculated were significantly different than previous values. The {sup 176}Hf resonance integral, based on this work, is approximately 73% higher than the ENDF/B-VI value. This is due primarily to the changes to resonance parameters in the 8 eV resonance, the neutron width presented in this work is more than twice that of the previous value. The calculated elemental hafnium resonance integral however, changed very little.

  15. Gravity-mode period spacings as seismic diagnostic for a sample of gamma Doradus stars from Kepler space photometry and high-resolution ground-based spectroscopy

    E-Print Network [OSTI]

    Van Reeth, T; Aerts, C; Papics, P I; Triana, S A; Zwintz, K; Degroote, P; Debosscher, J; Bloemen, S; Schmid, V S; De Smedt, K; Fremat, Y; Fuentes, A S; Homan, W; Hrudkova, M; Karjalainen, R; Lombaert, R; Nemeth, P; Oestensen, R; Van De Steene, G; Vos, J; Raskin, G; Van Winckel, H

    2015-01-01T23:59:59.000Z

    Gamma Doradus stars (hereafter gamma Dor stars) are gravity-mode pulsators of spectral type A or F. Such modes probe the deep stellar interior, offering a detailed fingerprint of their structure. Four-year high-precision space-based Kepler photometry of gamma Dor stars has become available, allowing us to study these stars with unprecedented detail. We selected, analysed, and characterized a sample of 67 gamma Dor stars for which we have Kepler observations available. For all the targets in the sample we assembled high-resolution spectroscopy to confirm their F-type nature. We found fourteen binaries, among which four single-lined binaries, five double-lined binaries, two triple systems and three binaries with no detected radial velocity variations. We estimated the orbital parameters whenever possible. For the single stars and the single-lined binaries, fundamental parameter values were determined from spectroscopy. We searched for period spacing patterns in the photometric data and identified this diagnosti...

  16. IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL 4. NO IO, OCTOBER 1995 1451 Correspondence

    E-Print Network [OSTI]

    Wirthlin, Michael J.

    University, Provo, UT 84602 USA. IEEE Log Number 9413844. 0.8, T 7-- 0.3t 0.1 O'*: n Fig. 1. PDF of the gpG dstribution family as a function of p. ,j= 1. member of the generalized p-Gaussian (gpG) distribution family parameter associated with fy(y(x)161. The gpG family of symmetric distributions includes many commonly

  17. The Parameter Space of Galaxy Formation

    E-Print Network [OSTI]

    Bower, R G; Goldstein, M; Benson, A J; Lacey, C G; Baugh, C M; Cole, S; Frenk, C S; .,

    2010-01-01T23:59:59.000Z

    Semi-analytic models are a powerful tool for studying the formation of galaxies. However, these models inevitably involve a significant number of poorly constrained parameters that must be adjusted to provide an acceptable match to the observed universe. In this paper, we set out to quantify the degree to which observational data-sets can constrain the model parameters. By revealing degeneracies in the parameter space we can hope to better understand the key physical processes probed by the data. We use novel mathematical techniques to explore the parameter space of the GALFORM semi-analytic model. We base our investigation on the Bower et al. 2006 version of GALFORM, adopting the same methodology of selecting model parameters based on an acceptable match to the local bJ and K luminosity functions. The model contains 16 parameters that are poorly constrained, and we investigate this parameter space using the Model Emulator technique, constructing a Bayesian approximation to the GALFORM model that can be rapid...

  18. A Search for Gamma-Ray Bursts and Pulsars, and the Application of Kalman Filters to Gamma-Ray Reconstruction

    E-Print Network [OSTI]

    B. B. Jones

    2002-02-04T23:59:59.000Z

    Part I describes the analysis of periodic and transient signals in EGRET data. A method to search for the transient flux from gamma-ray bursts independent of triggers from other gamma-ray instruments is developed. Several known gamma-ray bursts were independently detected, and there is evidence for a previously unknown gamma-ray burst candidate. Statistical methods using maximum likelihood and Bayesian inference are developed and implemented to extract periodic signals from gamma-ray sources in the presence of significant astrophysical background radiation. The analysis was performed on six pulsars and three pulsar candidates. The three brightest pulsars, Crab, Vela, and Geminga, were readily identified, and would have been detected independently in the EGRET data without knowledge of the pulse period. No significant pulsation was detected in the three pulsar candidates. Eighteen X-ray binaries were examined. None showed any evidence of periodicity. In addition, methods for calculating the detection threshold of periodic flux modulation were developed. The future hopes of gamma-ray astronomy lie in the development of the Gamma-ray Large Area Space Telescope, or GLAST. Part II describes the development and results of the particle track reconstruction software for a GLAST science prototype instrument beam test. The Kalman filtering method of track reconstruction is introduced and implemented. Monte Carlo simulations, very similar to those used for the full GLAST instrument, were performed to predict the instrumental response of the prototype. The prototype was tested in a gamma-ray beam at SLAC. The reconstruction software was used to determine the incident gamma-ray direction. It was found that the simulations did an excellent job of representing the actual instrument response.

  19. Search for the C-parity violating process J/{psi}{yields}{gamma}{gamma} via {psi}(2S){yields}{pi}{sup +}{pi}{sup -}J/{psi}

    SciTech Connect (OSTI)

    Ablikim, M.; Bai, J. Z.; Cai, X.; Chen, H. S.; Chen, H. X.; Chen, J. C.; Chen, Jin; Chen, Y. B.; Chu, Y. P.; Deng, Z. Y.; Du, S. X.; Fang, J.; Fang, S. S.; Gao, C. S.; Gu, S. D.; Guo, Y. N.; He, K. L.; Heng, Y. K.; Hu, H. M.; Hu, T. [Institute of High Energy Physics, Beijing 100049 (China)] (and others)

    2007-12-01T23:59:59.000Z

    Using 14.0x10{sup 6}{psi}(2S) events collected with the BES-II detector, the C-parity violating process J/{psi}{yields}{gamma}{gamma} via {psi}(2S){yields}{pi}{sup +}{pi}{sup -}J/{psi} is studied. We determine a new upper limit for the J/{psi}{yields}{gamma}{gamma} branching ratio of B(J/{psi}{yields}{gamma}{gamma})<2.2x10{sup -5} at the 90% C.L., which is about 20 times lower than the previous measurement.

  20. How to fool CMB parameter estimation

    E-Print Network [OSTI]

    William H. Kinney

    2000-05-19T23:59:59.000Z

    With the release of the data from the Boomerang and MAXIMA-1 balloon flights, estimates of cosmological parameters based on the Cosmic Microwave Background (CMB) have reached unprecedented precision. In this paper I show that it is possible for these estimates to be substantially biased by features in the primordial density power spectrum. I construct primordial power spectra which mimic to within cosmic variance errors the effect of changing parameters such as the baryon density and neutrino mass, meaning that even an ideal measurement would be unable to resolve the degeneracy. Complementary measurements are necessary to resolve this ambiguity in parameter estimation efforts based on CMB temperature fluctuations alone.