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1

Estimation of the parameters in the generalized gamma distribution  

E-Print Network (OSTI)

are printed out. C PROGRAM } ~ ESTIMATION OF PARAMETERS OF GENERALIZED GAMMA DISTRIBUTION C DIMENSION XO(500 ) eEPT(500) eFREQ (500) ePT& 500) ekF(500) ~ XN(500 ') DI MENS ION X & 2e 500 ) ~ S ( 2e 3) e Y (3 ~ '500 ) e TFREQ (3e 500 ) ~ SUMX (2 ) READ (5 e...+I )/TFREQ(2? I I ) ) Y C 3 ? I - I ) ~ALOG ( TFREO I 3 ~ I+I ) /TFREQ (3 ~ 1-1 ) ) WRITE(6?652) 81 L~LI ~ I 0~EXP(ALPHA) OS~OCH)2 ~ WRITE(6 ~ 300) FORMATtlHI ~ 46X?27HGENERALIZED GAMMA VARIABLES)r WRITE(6?301 ) (XN( J) ?J?:I )N) FORMAT( I 0 (9X? IOFI...

Collins, Claude Ann

2012-06-07T23:59:59.000Z

2

Cosmological Parameters From Supernovae Associated With Gamma-ray Bursts  

E-Print Network (OSTI)

We report estimates of the cosmological parameters $\\Omega_m$ and $\\Omega_{\\Lambda}$ obtained using supernovae (SNe) associated with gamma-ray bursts (GRBs) at redshifts up to 0.606. Eight high-fidelity GRB-SNe with well-sampled light curves across the peak are used. We correct their peak magnitudes for a luminosity-decline rate relation to turn them into accurate standard candles with dispersion $\\sigma = 0.18$ mag. We also estimate the peculiar velocity of the host galaxy of SN 1998bw, using constrained cosmological simulations. In a flat universe, the resulting Hubble diagram leads to best-fit cosmological parameters of $(\\Omega_m, \\Omega_{\\Lambda}) = (0.52^{+0.34}_{-0.31},0.48^{+0.31}_{-0.34})$. This exploratory study suggests that GRB-SNe can potentially be used as standardizable candles to high redshifts to measure distances in the universe and constrain cosmological parameters.

Li, Xue; Wojtak, Rados?aw

2014-01-01T23:59:59.000Z

3

Deconvolution of mixed gamma emitters using peak parameters  

SciTech Connect

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.

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

4

Constraint on the post-Newtonian parameter {gamma} on galactic size scales  

SciTech Connect

We constrain the post-Newtonian gravity parameter {gamma} on kiloparsec scales by comparing the masses of 15 elliptical lensing galaxies from the Sloan Lens ACS Survey as determined in two independent ways. The first method assumes only that Newtonian gravity is correct and is independent of {gamma}, while the second uses gravitational lensing which depends on {gamma}. More specifically, we combine Einstein radii and radial surface-brightness gradient measurements of the lens galaxies with empirical distributions for the mass concentration and velocity anisotropy of elliptical galaxies in the local universe to predict {gamma}-dependent probability distributions for the lens-galaxy velocity dispersions. By comparing with observed velocity dispersions, we derive a maximum-likelihood value of {gamma}=0.98{+-}0.07 (68% confidence). This result is in excellent agreement with the prediction of general relativity that {gamma}=1, which has previously been verified to this accuracy only on solar-system length scales.

Bolton, Adam S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, Massachusetts 02138 (United States); Rappaport, Saul; Burles, Scott [Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, Massachusetts 02139 (United States)

2006-09-15T23:59:59.000Z

5

Observations of Seyferts by OSSE and parameters of their X-ray/gamma-ray sources  

E-Print Network (OSTI)

We present a summary of spectra of Seyfert galaxies observed by the OSSE detector aboard Compton Gamma Ray Observatory. We obtain average spectra of Seyferts of type 1 and 2, and find they are well fitted by thermal Comptonization. We present detailed parameter ranges for the plasma temperature and the Compton parameter in the case of spherical and slab geometries. We find both the average and individual OSSE spectra of Seyfert 2s are significantly harder than those of Seyfert 1s, which difference can be due to anisotropy of Compton reflection and/or Thomson-thick absorption.

Andrzej A. Zdziarski; Juri Poutanen; W. Neil Johnson

2000-06-11T23:59:59.000Z

6

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

E-Print Network (OSTI)

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 $(0.3keV,3keV)$.

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

2006-02-04T23:59:59.000Z

7

Iwahori-Hecke algebra C3 This corresponds to the unitary dual of the group of type B 3 : The parameters  

E-Print Network (OSTI)

the Steinberg representation on the Levi component GL(1)Sp(2): The parameter is (#23; 1 ; 3 2 ; 1 2 ): Reducibility occurs at #23; 1 = 1 2 ; 5 2 , corresponding to (511); (7): The signs are #23; 1 0 #2; 12 0 #2; 1 3 1 #2; 11 + + + 1 2 + 0 0 + 5 2 + 0 + + The complementary series is the interval 0 #20; #23; 1

Barbasch, Dan

8

Constraining the dark energy and smoothness parameter with type Ia supernovae and gamma-ray bursts  

Science Journals Connector (OSTI)

The existence of inhomogeneities in the observed Universe modifies the distance-redshift relations thereby affecting the results of cosmological tests in comparison to the ones derived assuming spatially uniform models. By modeling the inhomogeneities through a Zeldovich-Kantowski-Dyer-Roeder approach which is phenomenologically characterized by a smoothness parameter ?, we rediscuss the constraints on the cosmic parameters based on type Ia supernovae (SNe Ia) and gamma-ray bursts (GRBs) data. The present analysis is restricted to a flat ?CDM model with the reasonable assumption that ? does not clump. A ?2 analysis using 557 SNe Ia data from the Union2 compilation data (R. Amanullah et al., Astrophys. J. 716, 712 (2010).) constrains the pair of parameters (?m, ?) to ?m=0.27-0.03+0.08 (2?) and ??0.25. A similar analysis based only on 59 Hymnium GRBs (H. Wei, J. Cosmol. Astropart. Phys. 08 (2010) 020.) constrains the matter density parameter to be ?m=0.35-0.24+0.62 (2?) while all values for the smoothness parameter are allowed. By performing a joint analysis, it is found that ?m=0.27-0.03+0.06 and ??0.52. As a general result, although considering that current GRB data alone cannot constrain the smoothness ? parameter, our analysis provides an interesting cosmological probe for dark energy even in the presence of inhomogeneities.

V. C. Busti; R. C. Santos; J. A. S. Lima

2012-05-07T23:59:59.000Z

9

Measurement of the decay rate and form factor parameter $\\alpha_{K}*$ in the decay $K_{L} \\rightarrow e^{+}e^{-}\\gamma$  

E-Print Network (OSTI)

The decay rate of the neutral K meson $\\mathrm{K_{L} \\rightarrow e^{+}e^{-}\\gamma}$ has been measured with the NA48 detector at the CERN SPS. A total of 6864 events has been observed with an estimated background of 10 events. The branching ratio is $\\mathrm{\\Gamma(K_{L} \\rightarrow e^{+}e^{-}\\gamma)/\\Gamma(K_{L} rightarrow all) = (1.06 \\pm 0.02_{stat.} \\pm 0.02_{sys.} \\pm 0.04_{calc.})\\times 10^{-5}}$. The parameter describing the relative strength of the two contributing amplitudes to this decay through $\\mathrm{\\alpha_{K^{*}}}$ intermediate seudoscalar or vector mesons, was measured to be $\\mathrm{\\alpha_{K^{*}} = -0.36 \\pm 0.06_{stat.} \\pm 0.02_{sys.}}$

Fanti, V; Musa, L; Marras, D; Nappi, A; Hay, B; Moore, R W; Moore, K N; Munday, D J; Needham, M D; Parker, M A; White, T O; Wotton, S A; Barr, Giles David; Bocquet, G; Bremer, J; Ceccucci, Augusto; Cundy, Donald C; Doble, Niels T; Funk, W; Gatignon, L; Gianoli, A; Gonidec, A; Govi, G; Grafström, P; Kubischta, Werner; Lacourt, A; Luitz, S; Kesseler, G; Matheys, J P; Norton, Alan Robert; Palestini, S; Panzer-Steindel, B; Schinzel, D; Taureg, Hans; Velasco, M; Vossnack, O; Wahl, H; Wirrer, G; Kekelidze, V D; Mestvirishvili, A; Potrebenikov, Yu K; Tatishvili, G T; Tkachev, A L; Zinchenko, A I; Boyle, O; Martin, V J; Knowles, I G; Parsons, H; Dalpiaz, Pietro; Duclos, J; Frabetti, P L; Martini, M; Petrucci, F; Porcu, M; Savrié, M; Bizzeti, A; Calvetti, M; Collazuol, G; Graziani, G; Iacopini, E; Lenti, M; Michetti, A; Becker, H G; Blümer, H; Buchholz, P; Coward, D H; Ebersberger, C; Fox, H; Kalter, A; Kleinknecht, K; Koch, U; Köpke, L; Renk, B; Scheidt, J; Schmidt, J; Schönharting, V; Schué, Yu; Wilhelm, R; Winhart, A; Wittgen, M; Chollet, J C; Crépé, S; Iconomidou-Fayard, L; Fayard, Louis; Ocariz, J; Unal, G; Vattolo, D; Wingerter-Seez, I; Anzivino, Giuseppina; Cenci, P; Lubrano, P; Pepé, M; Gorini, B; Calafiura, P; Carosi, R; Cerri, C; Cirilli, M; Costantini, F; Fantechi, R; Giudici, Sergio; Mannelli, I; Marzulli, V M; Pierazzini, G M; Sozzi, M; Chèze, J B; Cogan, J; De Beer, M; Debu, P; Formica, A; Granier de Cassagnac, R; Khristov, P Z; Mazzucato, E; Peyaud, B; Schanne, S; Turlay, René; Vallage, B; Augustin, I; Bender, M; Holder, M; Ziolkowski, M; Arcidiacono, R; Biino, C; Marchetto, F; Menichetti, E; Nassalski, J P; Rondio, Ewa; Szleper, M; Wislicki, W; Wronka, S; Dibon, Heinz; Fischer, G; Jeitler, Manfred; Markytan, Manfred; Mikulec, I; Neuhofer, Günther; Pernicka, Manfred; Taurok, Anton

1999-01-01T23:59:59.000Z

10

Distribution of Correspondence  

Directives, Delegations, and Requirements

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

1996-08-30T23:59:59.000Z

11

Correspondence Accountforthe`dark  

E-Print Network (OSTI)

and dark energy actually dominate many key processes. Likewise, it is time for more biologists to ventureCorrespondence Accountforthe`dark matter' of biology Philip Ball correctly opines of DNA that "we biological systems. Ball makes an apt analogy to the 1998 discovery that the expansion of the Universe

Hadly, Elizabeth

12

Comparison of the E(5) Critical Point Symmetry to the {gamma}-Rigid Solution of The Bohr Hamiltonian for {gamma} =30 deg  

SciTech Connect

A {gamma}-rigid solution of the Bohr Hamiltonian for {gamma}=30 deg. is derived. Bohr Hamiltonians {beta}-part being related to the second order Casimir operator of the Euclidean algebra E(4). The solution is called Z(4) since it is corresponds to the Z(5) model with the {gamma} variable ''frozen''. Parameter-free (up to overall scale factors) predictions for spectra and B(E2) transition rates are in close agreement to the E(5) critical point symmetry as well as to the experimental data in the Xe region around A=130.

Bonatsos, D.; Lenis, D.; Petrellis, D. [Institute of Nuclear Physics, National Center for Scientific Research 'Demokritos', GR-15310 Aghia Paraskevi, Attiki (Greece); Terziev, P. A. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 Tzarigrad Road, BG-1784 Sofia (Bulgaria); Yigitoglu, I. [Hasan Ali Yucel Faculty of Education, Istanbul University, TR-34470 Beyazit, Istanbul (Turkey)

2007-04-23T23:59:59.000Z

13

Time-dependent angular analysis of the decay $B_s^0 \\to J/\\psi \\phi$ and extraction of $\\Delta \\Gamma_s$ and the CP-violating weak phase $\\phi_s$ by ATLAS  

E-Print Network (OSTI)

A measurement of $B_s^0 \\to J/\\psi \\phi$ decay parameters, including the CP-violating weak phase $\\phi_s$ and the decay width difference $\\Delta \\Gamma_s$ is reported, using 4.9 fb$^{-1}$ of integrated luminosity collected in 2011 by the ATLAS detector from LHC pp collisions at a centre-of-mass energy $\\sqrt{s}$ = 7 TeV. The mean decay width $\\Gamma_s$ and the transversity amplitudes $|A_0(0)|^2$ and $|A_{||}(0)|^2$ are also measured. The values reported for these parameters are: \\begin{eqnarray}\\cr \\phi_s = 0.22 \\pm 0.41 (stat.) \\pm 0.10 (syst.) rad\\cr \\Delta \\Gamma_s = 0.053 \\pm 0.021 (stat.) \\pm 0.008 (syst.) ps^{-1}\\cr \\Gamma_s = 0.677 \\pm 0.007 (stat.) \\pm 0.004 (syst.) ps^{-1}\\cr |A_0(0)|^2 = 0.528 \\pm 0.006 (stat.) \\pm 0.009 (syst.)\\cr |A_{||}(0)|^2 = 0.220 \\pm 0.008 (stat.) \\pm 0.007 (syst.)\\cr\\end{eqnarray} where the values quoted for $\\phi_s$ and $\\Delta \\Gamma_s$ correspond to the solution compatible with the external measurements to which the strong phase $\\delta$ perpendicular is constrained and ...

Aad, Georges; Abbott, Brad; Abdallah, Jalal; Abdel Khalek, Samah; Abdelalim, Ahmed Ali; Abdinov, Ovsat; Aben, Rosemarie; Abi, Babak; Abolins, Maris; AbouZeid, Ossama; Abramowicz, Halina; Abreu, Henso; Acerbi, Emilio; Acharya, Bobby Samir; Adamczyk, Leszek; Adams, David; Addy, Tetteh; Adelman, Jahred; Adomeit, Stefanie; Adragna, Paolo; Adye, Tim; Aefsky, Scott; Aguilar-Saavedra, Juan Antonio; Agustoni, Marco; Aharrouche, Mohamed; Ahlen, Steven; Ahles, Florian; Ahmad, Ashfaq; Ahsan, Mahsana; Aielli, Giulio; Akdogan, Taylan; ? kesson, Torsten Paul Ake; Akimoto, Ginga; Akimov, Andrei; Alam, Mohammad; Alam, Muhammad Aftab; Albert, Justin; Albrand, Solveig; Aleksa, Martin; Aleksandrov, Igor; Alessandria, Franco; Alexa, Calin; Alexander, Gideon; Alexandre, Gauthier; Alexopoulos, Theodoros; Alhroob, Muhammad; Aliev, Malik; Alimonti, Gianluca; Alison, John; Allbrooke, Benedict; Allport, Phillip; Allwood-Spiers, Sarah; Almond, John; Aloisio, Alberto; Alon, Raz; Alonso, Alejandro; Alonso, Francisco; Alvarez Gonzalez, Barbara; Alviggi, Mariagrazia; Amako, Katsuya; Amelung, Christoph; Ammosov, Vladimir; Amorim, Antonio; Amram, Nir; Anastopoulos, Christos; Ancu, Lucian Stefan; Andari, Nansi; Andeen, Timothy; Anders, Christoph Falk; Anders, Gabriel; Anderson, Kelby; Andreazza, Attilio; Andrei, George Victor; Anduaga, Xabier; Anger, Philipp; Angerami, Aaron; Anghinolfi, Francis; Anisenkov, Alexey; Anjos, Nuno; Annovi, Alberto; Antonaki, Ariadni; Antonelli, Mario; Antonov, Alexey; Antos, Jaroslav; Anulli, Fabio; Aoki, Masato; Aoun, Sahar; Aperio Bella, Ludovica; Apolle, Rudi; Arabidze, Giorgi; Aracena, Ignacio; Arai, Yasuo; Arce, Ayana; Arfaoui, Samir; Arguin, Jean-Francois; Arik, Engin; Arik, Metin; Armbruster, Aaron James; Arnaez, Olivier; Arnal, Vanessa; Arnault, Christian; Artamonov, Andrei; Artoni, Giacomo; Arutinov, David; Asai, Shoji; Asfandiyarov, Ruslan; Ask, Stefan; ? sman, Barbro; Asquith, Lily; Assamagan, Ketevi; Astbury, Alan; Atkinson, Markus; Aubert, Bernard; Auge, Etienne; Augsten, Kamil; Aurousseau, Mathieu; Avolio, Giuseppe; Avramidou, Rachel Maria; Axen, David; Azuelos, Georges; Azuma, Yuya; Baak, Max; Baccaglioni, Giuseppe; Bacci, Cesare; Bach, Andre; Bachacou, Henri; Bachas, Konstantinos; Backes, Moritz; Backhaus, Malte; Badescu, Elisabeta; Bagnaia, Paolo; Bahinipati, Seema; Bai, Yu; Bailey, David; Bain, Travis; Baines, John; Baker, Oliver Keith; Baker, Mark; Baker, Sarah; Banas, Elzbieta; Banerjee, Piyali; Banerjee, Swagato; Banfi, Danilo; Bangert, Andrea Michelle; Bansal, Vikas; Bansil, Hardeep Singh; Barak, Liron; Baranov, Sergei; Barbaro Galtieri, Angela; Barber, Tom; Barberio, Elisabetta Luigia; Barberis, Dario; Barbero, Marlon; Bardin, Dmitri; Barillari, Teresa; Barisonzi, Marcello; Barklow, Timothy; Barlow, Nick; Barnett, Bruce; Barnett, Michael; Baroncelli, Antonio; Barone, Gaetano; Barr, Alan; Barreiro, Fernando; Barreiro Guimarães da Costa, João; Barrillon, Pierre; Bartoldus, Rainer; Barton, Adam Edward; Bartsch, Valeria; Basye, Austin; Bates, Richard; Batkova, Lucia; Batley, Richard; Battaglia, Andreas; Battistin, Michele; Bauer, Florian; Bawa, Harinder Singh; Beale, Steven; Beau, Tristan; Beauchemin, Pierre-Hugues; Beccherle, Roberto; Bechtle, Philip; Beck, Hans Peter; Becker, Anne Kathrin; Becker, Sebastian; Beckingham, Matthew; Becks, Karl-Heinz; Beddall, Andrew; Beddall, Ayda; Bedikian, Sourpouhi; Bednyakov, Vadim; Bee, Christopher; Beemster, Lars; Begel, Michael; Behar Harpaz, Silvia; Beimforde, Michael; Belanger-Champagne, Camille; Bell, Paul; Bell, William; Bella, Gideon; Bellagamba, Lorenzo; Bellina, Francesco; Bellomo, Massimiliano; Belloni, Alberto; Beloborodova, Olga; Belotskiy, Konstantin; Beltramello, Olga; Benary, Odette; Benchekroun, Driss; Bendtz, Katarina; Benekos, Nektarios; Benhammou, Yan; Benhar Noccioli, Eleonora; Benitez Garcia, Jorge-Armando; Benjamin, Douglas; Benoit, Mathieu; Bensinger, James; Benslama, Kamal; Bentvelsen, Stan; Berge, David; Bergeaas Kuutmann, Elin; Berger, Nicolas; Berghaus, Frank; Berglund, Elina; Beringer, Jürg; Bernat, Pauline; Bernhard, Ralf; Bernius, Catrin; Berry, Tracey; Bertella, Claudia; Bertin, Antonio; Bertolucci, Federico; Besana, Maria Ilaria; Besjes, Geert-Jan; Besson, Nathalie; Bethke, Siegfried; Bhimji, Wahid; Bianchi, Riccardo-Maria; Bianco, Michele; Biebel, Otmar; Bieniek, Stephen Paul; Bierwagen, Katharina; Biesiada, Jed; Biglietti, Michela; Bilokon, Halina; Bindi, Marcello; Binet, Sebastien; Bingul, Ahmet; Bini, Cesare; Biscarat, Catherine; Bittner, Bernhard; Black, Kevin; Blair, Robert; Blanchard, Jean-Baptiste; Blanchot, Georges

2012-01-01T23:59:59.000Z

14

A Self-Consistent Model For The Long-Term Gamma-Ray Spectral Variability of Cygnus X-1  

E-Print Network (OSTI)

The long-term transitions of the black hole candidate Cygnus X-1 (between the states gamma_1, gamma_2, and gamma_3) include the occasional appearance of a strong ~ MeV bump (gamma_1), whose strength appears to be anti-correlated with the continuum flux (~ 400 keV) due to the Compton upscattering of cold disk photons by the inner, hot corona. We develop a self-consistent disk picture that accounts naturally for these transitions and their corresponding spectral variations. We argue that the bump is due to the self-Comptonization of bremsstrahlung photons emitted predominantly near the plane of the corona itself. Our results suggest that a decrease by a factor of approx 2 in the viscosity parameter alpha is responsible for quenching this bump and driving the system to the gamma_2 state, whereas a transition from gamma_2 to gamma_3 appears to be induced by an increase of about 25 % in the accretion rate Mdot. In view of the fact that most of the transitions observed in this source seem to be of the gamma_2 to gamma_3 variety, we conclude that much of the long term gamma-ray spectral variability in Cygnus X-1 is due to these small fluctuations in Mdot. The unusual appearance of the gamma_1 state apparently reflects a change in the dissipative processes within the disk.

Fulvio Melia; Ranjeev Misra

1993-06-19T23:59:59.000Z

15

Correspondence  

Science Journals Connector (OSTI)

......Mechanization and Data Handling in Microbiology, Society for Applied Bacteriology Technical...edited by A. Baillie and R. J. Gilbert, London: Academic Press, pp. 1-22...microbial cultures, Canadian Journal of Microbiology, Vol. 14, pp. 271-279. PANKHURST......

B. L. Meek

1972-08-01T23:59:59.000Z

16

Constraints on Supersymmetric Flavour Models from b->s gamma  

E-Print Network (OSTI)

We consider the effects of departures from minimal flavour violations (MFV) in the context of CMSSM-like theories. Second and third generation off-diagonal elements in the Yukawa, sfermion, and trilinear mass matrices are taken to be non-zero at the GUT scale. These are run down together with MSSM parameters to the electroweak scale. We apply constraints from fermion masses and CKM matrix elements to limit the range of the new free parameters of the model. We determine the effect of the departure from MFV on the branching ratio of b->s gamma. We find that only when the expansion parameter in the down-squark sector is relatively large there is a noticeable effect, which tends to relax the lower limit from b->s gamma on the universal gaugino mass. We also find that the expansion parameter associated with the slepton sector needs to be smaller than the corresponding parameter in the down-squark sector in order to be compliant with the bound imposed by the branching ratio of tau-> mu gamma.

Olive, Keith A

2008-01-01T23:59:59.000Z

17

Reaction Rate Sensitivity of the gamma-Process Path  

E-Print Network (OSTI)

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.

T. Rauscher

2004-07-16T23:59:59.000Z

18

Gamma ray camera  

DOE Patents (OSTI)

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

Perez-Mendez, Victor (Berkeley, CA)

1997-01-01T23:59:59.000Z

19

Gamma ray camera  

DOE Patents (OSTI)

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

Perez-Mendez, V.

1997-01-21T23:59:59.000Z

20

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

E-Print Network (OSTI)

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.

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

2015-01-23T23:59:59.000Z

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21

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

E-Print Network (OSTI)

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 ...

Chernikova, Dina; Avdic, Senada; Pázsit, Imre; Nordlund, Anders

2014-01-01T23:59:59.000Z

22

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

SciTech Connect

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}.

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

23

Black Stars and Gamma Ray Bursts  

E-Print Network (OSTI)

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.

Tanmay Vachaspati

2007-06-08T23:59:59.000Z

24

Dimensioning hospital wards using the Erlang loss model Corresponding author  

E-Print Network (OSTI)

Dimensioning hospital wards using the Erlang loss model Corresponding author: A.M. de Bruin (MSc professionals, hospital consultants, and managers. In these discussions the occupancy rate is of great importance and often used as an input parameter. Most hospitals use the same target occupancy rate for all

25

Analytical solution for the Davydov-Chaban Hamiltonian with sextic potential for $\\gamma=30^{\\circ}$  

E-Print Network (OSTI)

An analytical solution for the Davydov-Chaban Hamiltonian with a sextic oscillator potential for the variable $\\beta$ and $\\gamma$ fixed to $30^{\\circ}$, is proposed. The model is conventionally called Z(4)-Sextic. For the considered potential shapes the solution is exact for the ground and $\\beta$ bands, while for the $\\gamma$ band an approximation is adopted. Due to the scaling property of the problem the energy and $B(E2)$ transition ratios depend on a single parameter apart from an integer number which limits the number of allowed states. For certain constraints imposed on the free parameter, which lead to simpler special potentials, the energy and $B(E2)$ transition ratios are parameter independent. The energy spectra of the ground and first $\\beta$ and $\\gamma$ bands as well as the corresponding $B(E2)$ transitions, determined with Z(4)-Sextic, are studied as function of the free parameter and presented in detail for the special cases. Numerical applications are done for the $^{128,130,132}$Xe and $^{19...

Buganu, P

2015-01-01T23:59:59.000Z

26

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

E-Print Network (OSTI)

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.

Daniele Fargion

1999-06-28T23:59:59.000Z

27

Thermal neutron capture gamma-rays  

SciTech Connect

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.

Tuli, J.K.

1983-01-01T23:59:59.000Z

28

Gamma Ray Bursts  

E-Print Network (OSTI)

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

Stahl, Bennett

2014-01-01T23:59:59.000Z

29

Credit Committee Email Correspondence Regarding Solyndra  

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

Email correspondence from January 2009 urging Loan Program staff to cease communications with Solyndra in order to allow for additional market analysis.

30

Compilation Congressional Correspondence, January 1, 2008 throught...  

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

JANUARY 1, 2008 THROUGH NOVEMBER 14, 2008 ALSO INCLUDES INDEX OF CONSTITUENT REFERRAL CORRESPONDENCE FOR THIS PERIOD Compiled by the Office of the Executive Secretariat...

31

BPA-2012-01416-FOIA Correspondence  

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

correspondence and photos related to this structure and its change from drilled pier foundation to grillage." A telephone conversation with your office clarified that all the Daily...

32

BPA-2012-01716-FOIA Correspondence  

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

number in any correspondence with the Agency about your request. You have requested: Records containing the amount of eminent domain or condemnation proceedings BPA has done...

33

Distribution of gamma-ray bursts over the celestial sphere  

Science Journals Connector (OSTI)

The fractal dimensionality of the distribution of gamma-ray bursts over the celestial sphere has been investigated....2...? 2 is obtained, corresponding to a uniform spatial distribution of burst sources.

P. A. Tarakanov

34

Gamma–ray bursts  

Science Journals Connector (OSTI)

...R. Priest and N. O. Weiss Gamma-ray bursts Martin J. Rees Institute of...Road, Cambridge CB3 0HA, UK Gamma-ray bursts, an enigma for more than 25...gamma-rays|neutron stars| Gamma-ray bursts By Martin J. Rees Institute...

2000-01-01T23:59:59.000Z

35

Gamma ray generator  

DOE Patents (OSTI)

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.

Firestone, Richard B; Reijonen, Jani

2014-05-27T23:59:59.000Z

36

Gamma Ray Bursts as cosmological tools  

E-Print Network (OSTI)

The use of Gamma Ray Bursts as ``standard candles'' has been made possible by the recent discovery of a very tight correlation between their rest frame intrinsic properties. This correlation relates the GRB prompt emission peak spectral energy E_peak to the energy E_gamma corrected for the collimation angle theta_jet of these sources. The possibility to use GRBs to constrain the cosmological parameters and to study the nature of Dark Energy are very promising.

G. Ghirlanda; G. Ghisellini; L. Nava; C. Firmani

2005-12-30T23:59:59.000Z

37

BPA-2011-00443-FOIA Correspondence  

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

this off ice can Thul-sda . Janual-' 6. 201 1. and has been assined a control number-. BPA-201 1-0044 3-F. Please use this number- in any correspondence with the .1ency about...

38

Quantum-classical correspondence in response theory  

E-Print Network (OSTI)

In this thesis, theoretical analysis of correspondence between classical and quantum dynamics is studied in the context of response theory. Thesis discusses the mathematical origin of time-divergence of classical response ...

Kryvohuz, Maksym

2008-01-01T23:59:59.000Z

39

Can gamma-ray bursts constrain quintessence?  

E-Print Network (OSTI)

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.

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

2005-04-27T23:59:59.000Z

40

System and method for motor parameter estimation  

DOE Patents (OSTI)

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.

Luhrs, Bin; Yan, Ting

2014-03-18T23:59:59.000Z

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


41

Gluon content of the {eta} and {eta}{sup '} mesons and the {eta}{gamma} , {eta}{sup '}{gamma} electromagnetic transition form factors  

SciTech Connect

We compute power-suppressed corrections to the {eta}{gamma} and {eta}{sup '}{gamma} transition form factors Q{sup 2}F{sub {eta}}{sub ({eta}}{sub {sup '}}{sub {gamma}}(Q{sup 2}) arising from the end point regions x{yields}0,1 by employing the infrared-renormalon approach. The contribution to the form factors from the quark and gluon content of the {eta},{eta}{sup '} mesons is taken into account using for the {eta}-{eta}{sup '} mixing the SU{sub f}(3) singlet {eta}{sub 1} and octet {eta}{sub 8} basis. The theoretical predictions obtained this way are compared with the corresponding CLEO data and restrictions on the input parameters (Gegenbauer coefficients) B{sub 2}{sup q}({eta}{sub 1}), B{sub 2}{sup g}({eta}{sub 1}), and B{sub 2}{sup q}({eta}{sub 8}) in the distribution amplitudes for the {eta}{sub 1},{eta}{sub 8} states with one nonasymptotic term are deduced. Comparison is made with the results from QCD perturbation theory.

Agaev, S.S.; Stefanis, N.G. [High Energy Physics Laboratory, Baku State University, Z. Khalilov Street 23, 370148 Baku (Azerbaijan); Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2004-09-01T23:59:59.000Z

42

Low energy secondary cosmic ray flux (gamma rays) monitoring and its constrains  

E-Print Network (OSTI)

Temporal variation of secondary cosmic rays (SCR) flux was measured during the several full and new moon and days close to them at Department of Physics, University of Mumbai, Mumbai (Geomagnetic latitude: 10.6 N), India. The measurements were done by using NaI (Tl) scintillation detector with energy threshold of 200 keV. The SCR flux shows sudden enhancement for approximately about 2 hour in counts during couple of events out of all experimental observations. The maximum Enhancement SCR flux is about 200% as compared to the diurnal trend of SCR temporal variations. Weather parameters (temperature and relative humidity) were continuously monitored during all observation. The influences of geomagnetic field, interplanetary parameters and tidal effect on SCR flux have been considered. Summed spectra corresponding to enhancement duration indicates appearance of atmospheric radioactivity which shows single gamma ray line. Detail investigation revealed the presence of radioactive Ar 41 . This measurements puts lim...

Raghav, Anil; Yadav, Virendra; Bijewar, Nitinkumar

2014-01-01T23:59:59.000Z

43

Impact parameter dependent colour glass condensate dipole model  

E-Print Network (OSTI)

We show that the colour glass condensate dipole model of Iancu, Itakura and Munier, improved to include the impact parameter dependence, gives a good fit to the total gamma* p cross section measured at HERA if the anomalous dimension at the saturation scale, gamma_s, is treated as a free parameter. We find that the optimum value of gamma_s is close to the value determined from numerical solution of the Balitsky-Kovchegov equation. We compare predictions of the model to data on exclusive diffractive vector meson production and deeply virtual Compton scattering at HERA. The model is found to be deficient for observables sensitive to very small dipole sizes, where an alternative model with explicit DGLAP evolution performs better. We determine the impact parameter dependent saturation scale and comment on the lack of conclusive evidence for perturbative saturation at HERA.

Watt, G

2007-01-01T23:59:59.000Z

44

W{gamma} Production and Limits on Anomalous WW{gamma} Couplings in pp Collisions at {radical}(s)=1.96 TeV  

SciTech Connect

We measure the cross section and the difference in rapidities between photons and charged leptons for inclusive W({yields}l{nu})+{gamma} production in e{gamma} and {mu}{gamma} final states. Using data corresponding to an integrated luminosity of 4.2 fb{sup -1} collected with the D0 detector at the Fermilab Tevatron Collider, the measured cross section times branching fraction for the process pp{yields}W{gamma}+X{yields}l{nu}{gamma}+X and the distribution of the charge-signed photon-lepton rapidity difference are found to be in agreement with the standard model. These results provide the most stringent limits on anomalous WW{gamma} couplings for data from hadron colliders: -0.4<{Delta}{kappa}{sub {gamma}<}0.4 and -0.08<{lambda}{sub {gamma}<}0.07 at the 95% C.L.

Abazov, V. M.; Alexeev, G. D.; Golovanov, G.; Kharzheev, Y. N.; Malyshev, V. L.; Tokmenin, V. V.; Vertogradov, L. S.; Yatsunenko, Y. A. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Abbott, B.; Gutierrez, P.; Jayasinghe, A.; Severini, H.; Skubic, P.; Strauss, M.; Svoisky, P. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Acharya, B. S.; Banerjee, S.; Mondal, N. K. [Tata Institute of Fundamental Research, Mumbai (India); Adams, M.; Bazterra, V. [University of Illinois at Chicago, Chicago, Illinois 60607 (United States)

2011-12-09T23:59:59.000Z

45

Gamma Ray Bursts Sudden, intense flashes of gamma rays  

E-Print Network (OSTI)

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

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

46

Gamma ray burst positrons  

Science Journals Connector (OSTI)

The international network of gamma ray burst detectors has provided redundant localizations for six gamma ray bursts with accuracies in the arcminute range. Catalog radio soft X?ray and optical searches have been performed for some of these events. The results of these searches are reviewed. Although radio X?ray and optical candidates are found in the error boxes no clear association between gamma ray bursts and other forms of emission has emerged to date. Optical radio searches are continuing.

K. Hurley

1982-01-01T23:59:59.000Z

47

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

E-Print Network (OSTI)

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.

Philipp Baerwald; Mauricio Bustamante; Walter Winter

2014-07-07T23:59:59.000Z

48

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

Science Journals Connector (OSTI)

Abstract 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.

Philipp Baerwald; Mauricio Bustamante; Walter Winter

2015-01-01T23:59:59.000Z

49

A CSP Field Theory with Helicity Correspondence  

E-Print Network (OSTI)

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.

Schuster, Philip

2014-01-01T23:59:59.000Z

50

A CSP Field Theory with Helicity Correspondence  

E-Print Network (OSTI)

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.

Philip Schuster; Natalia Toro

2014-04-02T23:59:59.000Z

51

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

SciTech Connect

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.

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

52

Generic Signatures of the Time Profiles of BATSE Cosmic Gamma-Ray Bursts  

Science Journals Connector (OSTI)

A new method is proposed, which allows the study of generic signatures of cosmic gamma-ray burst time histories. We average the 64 ms resolution time profiles of 275 bright bursts detected by BATSE. The profile of each burst is normalized by the maximum number of counts at the peak of the primary pulse, and individual pulses and interpulse valleys are selected from the normalized profiles by identical selection criteria. New generic temporal parameters are introduced, which characterize the duration and equivalent width of each pulse and the duration of each valley. The histograms of the total equivalent pulse width and summed pulse duration are bimodal. Bimodality is also seen in the histogram of the mean duration of individual pulses. Bursts from the short and long peaks of these distributions correspond to the two modes of the Third BATSE Burst Catalog T50 and T90 distributions. Therefore, these new burst parameters demonstrate that the observed bimodal temporal behavior results from properties of the pulsed emission of gamma-ray bursts. The long mode of the T90 histogram includes bursts with from one to ~20 pulses; the logarithmic mean pulse duration is 1.17 ± 0.09 s; for the long events with more than one pulse, the logarithmic mean valley duration is 1.28 ± 0.15 s. Bursts of the short mode of T90 are mainly single-pulse events, and the logarithmic mean pulse duration is much smaller, 0.20 ± 0.01 s. For multipulse bursts of the T90 long mode, marginal correlations were found between the parameters of the pulses and valleys and the number of pulses. The basic signatures of the evolution of pulses and valleys along the time course of bursts are examined. Conclusions are drawn concerning the physics of gamma-ray emission by taking into account these signatures.

Igor; Alexei; Michael S. Briggs; William S. Paciesas; Robert D. Preece; Geoffrey; Charles

1998-01-01T23:59:59.000Z

53

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

SciTech Connect

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.

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

54

Gamma ray bursts  

Science Journals Connector (OSTI)

The time histories size spectrum spatial distribution and repetition rates of gamma ray bursts are reviewed briefly. Evidence for a neutron star origin for gamma ray bursts may be found in many of these aspects of bursters. New results from optical searches are described. Substantial progress has been made recently in the optical identificaiton of the 1978 November 19 burst.

K. Hurley

1983-01-01T23:59:59.000Z

55

Directional gamma detector  

DOE Patents (OSTI)

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.

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

1981-01-01T23:59:59.000Z

56

DOE Standards and Corresponding Directives Crosswalk  

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

DOE Standards and Corresponding Directives Crosswalk DOE Standard Title Date DOE Order(s) Referenced Does DOE Order Reference Standard(s) DOE-TSL-1-99 Department of Energy Standards Index 5/99 ½ None ½ N/A. DOE-TSL-2-98 Directory of Points of Contact for the DOE Technical Standards Program 1/88 ½ None ½ N/A. DOE-TSL-4-99 Directory of DOE and Contractor Personnel Involved in Non- Government Standards Activities 5/99 ½ None ½ N/A. DOE-STD-0100T-93 Licensed Reactor Nuclear Safety Criteria Applicable to DOE Reactors 11/93 ½ DOE O 5480.6 ½ Order has been cancelled by N 251.4. DOE-STD-101-92 Compilation of Nuclear Safety Criteria for Potential Application to DOE Nonreactor Nuclear Facilities 3/92 ½ DOE O 5480.5 ½ Order has been cancelled by N 1321.140. DOE-HDBK-1001-96

57

Optical gamma thermometer  

DOE Patents (OSTI)

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.

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

2013-08-06T23:59:59.000Z

58

Gamma-ray binaries  

E-Print Network (OSTI)

Recent observations have shown that some compact stellar binaries radiate the highest energy light in the universe. The challenge has been to determine the nature of the compact object and whether the very high energy gamma-rays are ultimately powered by pulsar winds or relativistic jets. Multiwavelength observations have shown that one of the three gamma-ray binaries known so far, PSR B1259-63, is a neutron star binary and that the very energetic gamma-rays from this source and from another gamma-ray binary, LS I +61 303, may be produced by the interaction of pulsar winds with the wind from the companion star. At this time it is an open question whether the third gamma-ray binary, LS 5039, is also powered by a pulsar wind or a microquasar jet, where relativistic particles in collimated jets would boost the energy of the wind from the stellar companion to TeV energies.

I. F. Mirabel

2006-10-24T23:59:59.000Z

59

Magnetic Heisenberg-chain/pp-wave correspondence  

E-Print Network (OSTI)

We find a decoupling limit of planar N=4 super Yang-Mills (SYM) on R x S^3 in which it becomes equivalent to the ferromagnetic XXX_{1/2} Heisenberg spin chain in an external magnetic field. The decoupling limit generalizes the one found in hep-th/0605234 corresponding to the case with zero magnetic field. The presence of the magnetic field is seen to break the degeneracy of the vacuum sector and it has a non-trivial effect on the low energy spectrum. We find a general connection between the Hagedorn temperature of planar N=4 SYM on R x S^3 in the decoupling limit and the thermodynamics of the Heisenberg chain. This is used to study the Hagedorn temperature for small and large value of the effective coupling. We consider the dual decoupling limit of type IIB strings on AdS_5 x S^5. We find a Penrose limit compatible with the decoupling limit that gives a magnetic pp-wave background. The breaking of the symmetry by the magnetic field on the gauge theory side is seen to have a geometric counterpart in the derivation of the Penrose limit. We take the decoupling limit of the pp-wave spectrum and succesfully match the resulting spectrum to the low energy spectrum on the gauge theory side. This enables us to match the Hagedorn temperature of the pp-wave to the Hagedorn temperature of the gauge theory for large effective coupling. This generalizes the results of hep-th/0608115 to the case of non-zero magnetic field.

Troels Harmark; Kristjan R. Kristjansson; Marta Orselli

2006-11-22T23:59:59.000Z

60

Gamma-ray Astronomy  

E-Print Network (OSTI)

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

Jim Hinton

2007-12-20T23:59:59.000Z

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


61

Sensitivity analysis of Stirling engine design parameters  

SciTech Connect

In the preliminary Stirling engine design process, the values of some design parameters (temperature ratio, swept volume ratio, phase angle and dead volume ratio) have to be assumed; as a matter of fact it can be difficult to determine the best values of these parameters for a particular engine design. In this paper, a mathematical model is developed to analyze the sensitivity of engine's performance variations corresponding to variations of these parameters.

Naso, V.; Dong, W.; Lucentini, M.; Capata, R.

1998-07-01T23:59:59.000Z

62

Efficient navigation of parameter landscapes  

Science Journals Connector (OSTI)

The covariance matrix of the gradient of the cost function contains a great deal of information about a parameter space. The eigenvectors of the covariance matrix form an optimal basis (in the sense of data compression) for the gradient. Since search algorithms base their decisions on the gradient (often in an indirect fashion) the eigenvectors in some sense form an optimal set of generators for navigating parameter landscapes. For problems involving a long valley there is usually an eigenvector oriented parallel to the valley. Search algorithms based on the optimal generators may find the deepest point in the valley several times faster than algorithms based on other generators. The covariance matrix also contains information about the key underlying parameters. The most important parameters correspond to the eigenvectors associated with the largest eigenvalues. This information can be exploited to reparametrize with a smaller number of parameters. The covariance matrix is the integral of the outer product of the gradient over the parameter space. Obtaining a good estimate of this integral with the Monte Carlo method usually requires relatively little effort even for high?dimensional parameter spaces. Examples are presented for geoacoustic inverse problems involving acoustic sources and receivers located in the ocean.

Michael D. Collins

1994-01-01T23:59:59.000Z

63

Constraints on Lorentz invariance violation from gamma-ray burst GRB090510  

E-Print Network (OSTI)

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.

Zhi Xiao; Bo-Qiang Ma

2010-01-18T23:59:59.000Z

64

Extraction of {gamma} from charmless hadronic B {yields} PP decays using SU(3) flavor symmetry  

SciTech Connect

The decays of B mesons to a pair of charmless pseudoscalar mesons (PP decays) have been analyzed within the framework of flavor SU(3) symmetry and quark-diagrammatic topological approach. Flavor symmetry breaking is taken into account in tree (T) amplitudes through ratios of decay constants fK and f{pi}; exact SU(3) is assumed elsewhere. Acceptable fits to B {yields} PP branching ratios and CP asymmetries are obtained with tree, color-suppressed and QCD penguin amplitudes. Singlet penguin amplitude was introduced to describe decay amplitudes of the modes with {eta} and {eta}' mesons in the final state. Electroweak penguin amplitudes were expressed in terms of the corresponding tree-level diagrams. Values of the weak phase {gamma} were found to be consistent with the current indirect bounds from other analyses of CKM parameters.

Suprun, Denis A. [High Energy Theory Group, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2006-07-11T23:59:59.000Z

65

Gamma-Ray Bursts  

E-Print Network (OSTI)

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

P. Meszaros

2006-05-30T23:59:59.000Z

66

Gamma Ray Bursts as Cosmological Tools  

Science Journals Connector (OSTI)

The use of Gamma Ray Bursts as “standard candles” has been made possible by the recent discovery of a very tight correlation between their rest frame intrinsic properties. This correlation relates the GRB prompt emission peak spectral energy E peak to the energy E ? corrected for the collimation angle ?jet of these sources. The possibility to use GRBs to constrain the cosmological parameters and to study the nature of Dark Energy are very promising.

G. Ghirlanda; G. Ghisellini; L. Nava; C. Firmani

2005-01-01T23:59:59.000Z

67

The Polarization Dependence of Gamma-Gamma Absorption - Implications for Gamma-Ray Bursts and Blazars  

E-Print Network (OSTI)

This paper presents an analysis of the dependence of the opacity for high-energy gamma-rays to gamma-gamma absorption by low-energy photons, on the polarization of the gamma-ray and target photons. This process has so far only been considered using the polarization-averaged gamma-gamma absorption cross section. It is demonstrated that in the case of polarized gamma-ray emission, subject to source-intrinsic gamma-gamma absorption by polarized target photons, this may lead to a slight over-estimation of the gamma-gamma opacity by up to ~ 10 % in the case of a perfectly ordered magnetic field. Thus, for realistic astrophysical scenarios with partially ordered magnetic fields, the use of the polarization-averaged gamma-gamma cross section is justified for practical purposes, such as estimates of minimum Doppler factors inferred for gamma-ray bursts and blazars, based on gamma-gamma transparency arguments, and this paper quantifies the small error incurred by the unpolarized-radiation approximation. Furthermore, i...

Boettcher, Markus

2014-01-01T23:59:59.000Z

68

Real time gamma-ray signature identifier  

DOE Patents (OSTI)

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.

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

69

Robust Limits on Lorentz Violation from Gamma-Ray Bursts  

E-Print Network (OSTI)

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.

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

2005-10-06T23:59:59.000Z

70

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

SciTech Connect

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.

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

71

Correspondence Clustering: An Approach to Cluster Multiple Related Spatial Datasets  

E-Print Network (OSTI)

Correspondence Clustering: An Approach to Cluster Multiple Related Spatial Datasets Vadeerat spatial datasets. This capability is important for change analysis and contrast mining. In this paper spatial datasets by maximizing cluster interestingness and correspondence between clusters derived from

Eick, Christoph F.

72

Gamma Ray Bursts  

E-Print Network (OSTI)

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

Peter Mészáros

2012-04-12T23:59:59.000Z

73

Gamma-ray burst models  

Science Journals Connector (OSTI)

...research-article Discussion Meeting Issue Gamma-ray bursts organized by Alan Wells, Ralph...J. Wijers and Martin Rees Gamma-ray burst models Andrew King * * ( ark...various possibilities for making gamma-ray bursts, particularly from close binaries...

2007-01-01T23:59:59.000Z

74

Impact parameter dependent colour glass condensate dipole model  

E-Print Network (OSTI)

We show that the colour glass condensate dipole model of Iancu, Itakura and Munier, improved to include the impact parameter dependence, gives a good fit to the total gamma* p cross section measured at HERA if the anomalous dimension at the saturation scale, gamma_s, is treated as a free parameter. We find that the optimum value of gamma_s = 0.46 is close to the value determined from numerical solution of the Balitsky-Kovchegov equation. The impact parameter dependent saturation scale is generally less than 0.5 GeV^2 in the HERA kinematic regime for the most relevant impact parameters b ~ 2-3 GeV^{-1}. We compare predictions of the model to data on the longitudinal and heavy flavour structure functions, exclusive diffractive vector meson production and deeply virtual Compton scattering at HERA. The model is found to be deficient for observables sensitive to moderately small dipole sizes, where an alternative model with explicit DGLAP evolution performs better. The energy dependence of exclusive diffractive processes is shown to provide an important discriminator between different dipole model cross sections.

G. Watt; H. Kowalski

2007-12-17T23:59:59.000Z

75

PIA - HS Correspondence Tracking System (HSCT) | Department of...  

Office of Environmental Management (EM)

PIA - HS Correspondence Tracking System (HSCT) More Documents & Publications PIA - INL SECURITY INFORMATION MANAGEMENT SYSTEM BUSINESS ENCLAVE PIA - INL PeopleSoft - Human...

76

Department of Energy Response to Correspondence from Mary Celeste...  

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

Mary Celeste Harris Related to District of Columbia Public Service Commission Docket No. EO-05-01 Department of Energy Response to Correspondence from Mary Celeste Harris Related...

77

Department of Energy Response to Correspondence from Alexandria...  

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

& Publications Department of Energy Response to Correspondence from Mary Celeste Harris Related to District of Columbia Public Service Commission Docket No. EO-05-01 Comments...

78

Gamma Irradiation | ORNL Neutron Sciences  

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

Gamma Irradiation Gamma Irradiation Gamma Irradiation Facility Gamma irradiation chamber Gamma irradiation chamber. The HFIR Gamma Irradiation Facility is an experimental facility designed to irradiate materials with gamma radiation from spent fuel elements. The facility chamber is stainless steel and is made of 0.065-thick tubing to maximize the internal dimensions of the chamber. This allows for the largest samples possible that can still fit inside the cadmium post of the spent fuel loading station positions. The interior chamber is approximately 3.75 inches inside diameter and accommodates samples up to 25 inches long. There are two configurations for the chamber assembly, with the only difference being the plugs. The uninstrumented configuration has a top plug that is used for installation of the samples, to support the inert gas

79

E-Print Network 3.0 - annihilation gamma rays Sample Search Results  

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

32 3 grid 74 94 3.05 ora SPEC ray tracing 650 array elements... .0 0.5 1.0 1.5 2.0 GammaGammaGammaGammaGammaGamma GammaGammaGammaGammaGammaGamma GammaGammaGamma...

80

E-Print Network 3.0 - atmospheric gamma rays Sample Search Results  

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

32 3 grid 74 94 3.05 ora SPEC ray tracing 650 array elements... .0 0.5 1.0 1.5 2.0 GammaGammaGammaGammaGammaGamma GammaGammaGammaGammaGammaGamma GammaGammaGamma...

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


81

Critically Finite Correspondences and Subgroups of the Modular Group  

Science Journals Connector (OSTI)

......the same eight puncture points as being at the vertices...1 -- y, OOH^OO Lift of correspondence: x...z: as III(i) Lift of correspondence: r...its faces, the eight points on critical orbits in our examples are the four 'roof points on the equator......

Shaun Bullett

1992-09-01T23:59:59.000Z

82

Use and misuse of correspondence analysis in codon usage studies  

E-Print Network (OSTI)

Use and misuse of correspondence analysis in codon usage studies Guy PerrieÁre* and Jean Thioulouse; Accepted August 22, 2002 ABSTRACT Correspondence analysis has frequently been used for codon usage studies but this method is often misused. Because amino acid composition exerts constraints on codon usage, it is common

Thioulouse, Jean

83

LASER-PLASMA-ACCELERATOR-BASED GAMMA GAMMA COLLIDERS  

E-Print Network (OSTI)

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

Schroeder, C. B.

2010-01-01T23:59:59.000Z

84

Poroelasticity: parameters reviewed  

Science Journals Connector (OSTI)

......pressure parameter), storage parameters, the Darcy...the variability of the storage coefficient as function...effects associated with the long-term compaction of sedimentary...underground nuclear waste storage, exploitation of geothermal......

H.-J. Kümpel

1991-06-01T23:59:59.000Z

85

The GAMMA-400 Space Mission  

E-Print Network (OSTI)

GAMMA-400 is a new space mission which will be installed on board the Russian space platform Navigator. It is scheduled to be launched at the beginning of the next decade. GAMMA-400 is designed to study simultaneously gamma rays (up to 3 TeV) and cosmic rays (electrons and positrons from 1 GeV to 20 TeV, nuclei up to 10$^{15}$-10$^{16}$ eV). Being a dual-purpose mission, GAMMA-400 will be able to address some of the most impelling science topics, such as search for signatures of dark matter, cosmic-rays origin and propagation, and the nature of transients. GAMMA-400 will try to solve the unanswered questions on these topics by high-precision measurements of the Galactic and extragalactic gamma-ray sources, Galactic and extragalactic diffuse emission and the spectra of cosmic-ray electrons + positrons and nuclei, thanks to excellent energy and angular resolutions.

Cumani, P; 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; 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; Leonov, A A; Loginov, V A; Longo, F; Maestro, P; Marrocchesi, P S; Menshenin, A L; 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

86

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

DOE Patents (OSTI)

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.

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

87

Department of Energy Response to Correspondence from Mary Celeste Harris  

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

Mary Celeste Mary Celeste Harris Related to District of Columbia Public Service Commission Docket No. EO-05-01 Department of Energy Response to Correspondence from Mary Celeste Harris Related to District of Columbia Public Service Commission Docket No. EO-05-01 Docket No. EO-05-01: Department of Energy response to correspondence from Mary Celeste Harris related to District of Columbia Public Service Commission Docket No. EO-05-01 regarding operation of Mirnat Corporation's Potomac River Generating Station. Department of Energy Response to Correspondence from Mary Celeste Harris Related to District of Columbia Public Service Commission Docket No. EO-05-01 More Documents & Publications Department of Energy Response to Correspondence from Alexandria Homeowners and Citizens Associations Related to District of Columbia Public Service

88

Zero sound modes in the AdS/CFT correspondence  

E-Print Network (OSTI)

We examine the effects of zero sound wave excitations of charged fermion species living around the charged black hole of an AdS/CFT spacetime. In particular, we show that these bulk modes cause corresponding singularities ...

Roxlo, Thomas (Thomas Q.)

2012-01-01T23:59:59.000Z

89

4d/2d correspondence : instantons and W-algebras.  

E-Print Network (OSTI)

?? In this thesis, we study the 4d/2d correspondence of Alday-Gaiotto-Tachikawa, which relates the class of 4-dimensional N=2 gauge theories (theories of class S) to… (more)

Song, Jaewon

2012-01-01T23:59:59.000Z

90

Search for neutrinos from Gamma-Ray Bursts with ANTARES  

E-Print Network (OSTI)

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.

Eleonora Presani

2011-04-20T23:59:59.000Z

91

Constraining axion by polarized prompt emission from gamma ray bursts  

E-Print Network (OSTI)

A polarized gamma ray emission spread over a sufficiently wide energy band from a strongly magnetized astrophysical object like gamma ray bursts (GRBs) offers an opportunity to test the hypothesis of invisible axion. The axionic induced dichroism of gamma rays at different energies should cause a misalignment of the polarization plane for higher energy events relative to that one for lower energies events resulting in the loss of statistics needed to form a pattern of the polarization signal to be recognized in a detector. According to this, any evidence of polarized gamma rays coming from an object with extended magnetic field could be interpreted as a constraint on the existence of the invisible axion for a certain parameter range. Based on reports of polarized MeV emission detected in several GRBs we derive a constraint on the axion-photon coupling. This constraint $\\g_{a\\gamma\\gamma}\\le 2.2\\cdot 10^{-11} {\\rm GeV^{-1}}$ calculated for the axion mass $m_a=10^{-3} {\\rm eV}$ is competitive with the sensitivity of CAST and becomes even stronger for lower masses.

A. Rubbia; A. S. Sakharov

2007-08-21T23:59:59.000Z

92

Gamma-ray burst populations.  

E-Print Network (OSTI)

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

Virgili, Francisco J.

2011-01-01T23:59:59.000Z

93

Gamma emission in precompound reactions: 2, Numerical application  

SciTech Connect

The analytically obtained results of the preceding paper on capture gamma ray reactions are used for a direct numerical calculation. It turns out that this formulation allows for a parameter free description of gamma emission in precompound reactions. As an example we choose reactions induced by 14.1 MeV neutrons incident on {sup 59}CO, {sup 93}Nb and {sup 181}Ta. The individual contributions of different terms to the total cross section are discussed in detail and a comparison to experimental data is pursued.

Herman, M.; Reffo, G. (Ente Nazionale Energie Alternative, Bologna (Italy)); Hoering, A. (Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany) Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory)

1992-01-01T23:59:59.000Z

94

Gamma emission in precompound reactions: 2, Numerical application  

SciTech Connect

The analytically obtained results of the preceding paper on capture gamma ray reactions are used for a direct numerical calculation. It turns out that this formulation allows for a parameter free description of gamma emission in precompound reactions. As an example we choose reactions induced by 14.1 MeV neutrons incident on {sup 59}CO, {sup 93}Nb and {sup 181}Ta. The individual contributions of different terms to the total cross section are discussed in detail and a comparison to experimental data is pursued.

Herman, M.; Reffo, G. [Ente Nazionale Energie Alternative, Bologna (Italy); Hoering, A. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany)]|[Washington Univ., Seattle, WA (United States). Inst. for Nuclear Theory

1992-09-01T23:59:59.000Z

95

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

E-Print Network (OSTI)

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.

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

1998-06-05T23:59:59.000Z

96

Gamma Log | Open Energy Information  

Open Energy Info (EERE)

Gamma Log Gamma Log Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Technique: Gamma Log Details Activities (6) Areas (6) Regions (0) NEPA(0) Exploration Technique Information Exploration Group: Downhole Techniques Exploration Sub Group: Well Log Techniques Parent Exploration Technique: Well Log Techniques Information Provided by Technique Lithology: provides information on changes in rock type near the wellbore from changes in measured gamma radiation Stratigraphic/Structural: using multiple gamma logs over an area, the depth to the sandstone and shale layers can be correlated over larger areas Hydrological: Thermal: Cost Information Low-End Estimate (USD): 0.2525 centUSD 2.5e-4 kUSD 2.5e-7 MUSD 2.5e-10 TUSD / foot Median Estimate (USD): 0.3838 centUSD

97

Cosmological parameters are dressed  

E-Print Network (OSTI)

In the context of the averaging problem in relativistic cosmology, we provide a key to the interpretation of cosmological parameters by taking into account the actual inhomogeneous geometry of the Universe. We discuss the relation between `bare' cosmological parameters determining the cosmological model, and the parameters interpreted by observers with a ``Friedmannian bias'', which are `dressed' by the smoothed-out geometrical inhomogeneities of the surveyed spatial region.

Thomas Buchert; Mauro Carfora

2002-10-15T23:59:59.000Z

98

Department of Energy Response to Correspondence from Alexandria Homeowners  

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

Alexandria Alexandria Homeowners and Citizens Associations Related to District of Columbia Public Service Commission Docket No. EO-05-01 Department of Energy Response to Correspondence from Alexandria Homeowners and Citizens Associations Related to District of Columbia Public Service Commission Docket No. EO-05-01 Docket No. EO-05-01: Department of Energy response to correspondence from Alexandria Homeowners and Citizens Associations related to District of Columbia Public Service Commission Docket No. EO-05-01 regarding operation of Mirnat Corporation's Potomac River Generating Station. Department of Energy Response to Correspondence from Alexandria Homeowners and Citizens Associations Related to District of Columbia Public Service Commission Docket No. EO-05-01 More Documents & Publications

99

EM SSAB Correspondence & Briefings | Department of Energy  

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

Correspondence & Briefings Correspondence & Briefings EM SSAB Correspondence & Briefings 2012 March 12, 2012 Memorandum: FY 2014 through FY 2018 Initial Budget Formulation "Kick-Off" From: Teresa Tyborowski, Acting Deputy Assistant Secretary for Program Planning & Budget (EM-60) Subject: Fiscal Years 2014 through 2018 Initial Budget Formulation "Kick-Off" 2011 March 30, 2011 Memorandum: Guidance for Participation of the EM SSAB, Stakeholders, Regulators, and Tribal Governments in EM FY 2013 Budget Request From: Dae Y. Chung, Principle Deputy Assistant Secretary for EM (EM-2) Subject: Guidance for Participation of the EM SSAB, Stakeholders, Regulators, and Tribal Governments in EM FY 2013 Budget Request 2010 October 5, 2010 Minutes: EM SSAB Chairs Budget Conference Call

100

J. Chem. Sci., Vol. 119, No. 2, March 2007, pp. 6169. Indian Academy of Sciences. *For correspondence  

E-Print Network (OSTI)

J. Chem. Sci., Vol. 119, No. 2, March 2007, pp. 61­69. © Indian Academy of Sciences. 61 *For intermediate structure. The value of a property (parameter) observed at any point on the denaturation titration of molecules at the point of observation corresponding to p1 and p2 res- pectively, with (f1 + f2) = 1

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


101

Co-axial, high energy gamma generator  

DOE Patents (OSTI)

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.

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

2011-08-16T23:59:59.000Z

102

NREL: PVWatts - How to Change Parameters  

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

Change Parameters Change Parameters The PVWattsTM calculator allows users to substitute its default input parameters with custom values. Learn how to change the PVWatts parameters for: DC rating DC-to-AC derate factor Array type Tilt angle Azimuth angle Electricity cost DC Rating The size of a photovoltaic (PV) system is its nameplate DC power rating. This is determined by adding the PV module power listed on the nameplates of the PV modules in watts and then dividing the sum by 1,000 to convert it to kilowatts (kW). PV module power ratings are for standard test conditions (STC) of 1,000 W/m2 solar irradiance and 25°C PV module temperature. The default PV system size is 4 kW. This corresponds to a PV array area of approximately 35 m2 (377 ft2). Caution: For correct results, the DC rating input must be the nameplate DC

103

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

SciTech Connect

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.

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

104

Catalytic process for converting 2-oxazolidinones to their corresponding alkanolamines  

SciTech Connect

This invention provides a process for recovering alkanolamines, e.g. diisopropanolamine, from their corresponding cyclic reaction products (e.g., oxazolidinones), which products are the result of the reaction of CO/sub 2/ and the alkanolamine, a situation commonly encountered in acid gas removal processes employing the alkanolamines alone or in combination with other liquids such as sulfolane (tetrahydrothiophene-1,1 -dioxide). The process involves hydrolyzing the oxazolidinones in the presence of a small but catalytically effective amount of an amine, preferably from about 2 to 10 weight percent, based on 2-oxazolidinones. Preferably, the amine is the alkanolamine precursor of the corresponding 2-oxazolidinone.

Miller, A. E.

1985-04-30T23:59:59.000Z

105

COMPACT, TUNABLE COMPTON SCATTERING GAMMA-RAY SOURCES  

SciTech Connect

Recent progress in accelerator physics and laser technology have enabled the development of a new class of gamma-ray light sources based on Compton scattering between a high-brightness, relativistic electron beam and a high intensity laser pulse produced via chirped-pulse amplification (CPA). A precision, tunable gamma-ray source driven by a compact, high-gradient X-band linac is currently under development at LLNL. High-brightness, relativistic electron bunches produced by the linac interact with a Joule-class, 10 ps laser pulse to generate tunable {gamma}-rays in the 0.5-2.5 MeV photon energy range via Compton scattering. The source will be used to excite nuclear resonance fluorescence lines in various isotopes; applications include homeland security, stockpile science and surveillance, nuclear fuel assay, and waste imaging and assay. The source design, key parameters, and current status are presented.

Hartemann, F V; Albert, F; Anderson, G G; Anderson, S G; Bayramian, A J; Betts, S M; Chu, T S; Cross, R R; Ebbers, C A; Fisher, S E; Gibson, D J; Ladran, A S; Marsh, R A; Messerly, M J; O'Neill, K L; Semenov, V A; Shverdin, M Y; Siders, C W; McNabb, D P; Barty, C J; Vlieks, A E; Jongewaard, E N; Tantawi, S G; Raubenheimer, T O

2009-08-20T23:59:59.000Z

106

* Corresponding author. AN INTERACTIVE SCHEME FOR BUILDING MODELING USING THE  

E-Print Network (OSTI)

* Corresponding author. AN INTERACTIVE SCHEME FOR BUILDING MODELING USING THE SPLIT modeling is the 3D building model. It is essential in many applications, such as 3D GIS, cyber city, true-orthophoto generation, etc. Due to the huge demand of 3D building model, an effective solution for geometrical building

Salvaggio, Carl

107

Heat transfer from nanoparticles: a corresponding state analysis  

E-Print Network (OSTI)

Heat transfer from nanoparticles: a corresponding state analysis Samy Merabia , Sergei Shenogin that inhibits the formation of an insulating vapor film. heat transfer | nanoparticles | liquids | phase transitions Introduction Sub-micron scale heat transfer is attracting a growing inter- est, motivated by both

Paris-Sud XI, Université de

108

Computing with the Lie correspondence Scott H. Murray  

E-Print Network (OSTI)

Computing with the Lie correspondence Scott H. Murray University of Sydney July 30, 2009 #12;Linear: symplectic groups Sp2n(F) Types B and D: orthogonal Types E, F, G: exceptional #12;Almost reductive Lie The Lie algebra of a connected reductive linear algebraic group I sln(F) is almost reductive F has

Murray, Scott H.

109

*Corresponding author. Atmospheric Environment 34 (2000) 1921}1957  

E-Print Network (OSTI)

of O , O -precursors (including the odd-hydrogen free radicals), the oxidation products*Corresponding author. Atmospheric Environment 34 (2000) 1921}1957 Methods for gas concludes with a brief discussion of calibration methods and standards and tests that should be routinely

Sillman, Sanford

110

A Functional Correspondence between Evaluators and Abstract Machines  

E-Print Network (OSTI)

A Functional Correspondence between Evaluators and Abstract Machines Mads Sig Ager, Dariusz machine from an ordinary call-by-name evaluator and by deriving an ordinary call-by-value evaluator from Felleisen et al.'s CEK-machine. The first derivation is strikingly simpler than what can be found

Hutton, Graham

111

Scientific Correspondence ETHYLENE RESPONSE 1 Histidine Kinase Activity  

E-Print Network (OSTI)

Scientific Correspondence ETHYLENE RESPONSE 1 Histidine Kinase Activity of Arabidopsis Promotes General Hospital, Department of Genetics, Harvard Medical School, Boston, Massachusetts 02114 ETHYLENE RESPONSE 1 (ETR1) is one of five receptors for the plant hormone ethylene (Bleecker et al., 1988; Chang et

Sheen, Jen

112

* Corresponding author. Journal of Biomechanics 31 (1998) 239--245  

E-Print Network (OSTI)

where the primary energy system utilized is aerobic. Further, V O is a global measure of the energetic* Corresponding author. Journal of Biomechanics 31 (1998) 239--245 Standard mechanical energy to quantify mechanical energy expenditure (MEE) in human movement. To achieve this goal, a theoretical model

113

* Corresponding author. Chemical Engineering Science 56 (2001) 1035}1039  

E-Print Network (OSTI)

. A simpli"ed model of the corona reactor is utilized in conjunction with dynamic optimization. Scaling of this optimization strategy. 2001 Published by Elsevier Science Ltd. Keywords: Pulsed corona reactor; Advanced* Corresponding author. Chemical Engineering Science 56 (2001) 1035}1039 Optimization

Palanki, Srinivas

114

Correspondence Laboratory observations of debris-bearing ice facies frozen  

E-Print Network (OSTI)

, others argue that supercooling is not the only mechanism for producing thick basal ice sequencesCorrespondence Laboratory observations of debris-bearing ice facies frozen from supercooled water. Supercooling has been invoked to explain anomalously thick basal ice sequences beneath temperate glaciers

Knight, Peter G.

115

nature methods | VOL.6 NO.1 | JANUARY 2009 | 3 correspondence  

E-Print Network (OSTI)

free energies and binding affinities according to the respective thermodynamic cycle (Fig. 1a). We using ensembles of structures. (a) Thermodynamic cycle for the computation of folding free energiesnature methods | VOL.6 NO.1 | JANUARY 2009 | 3 correspondence Predicting free energy changes using

Caflisch, Amedeo

116

Motion Without Correspondence from Tomographic Projections by Bayesian Inversion Theory  

E-Print Network (OSTI)

Computing 3D reconstructions from X-ray projections is al- ready possible in some medical applications by Bayesian formalism as we want to handle either sparsely collected or limited-angle data, which are beyondMotion Without Correspondence from Tomographic Projections by Bayesian Inversion Theory S. S

Brandt, Sami

117

The anatomy of $\\gamma$-ray pulsar light curves  

E-Print Network (OSTI)

We previously obtained constraints on the viewing geometries of 6 Fermi LAT pulsars using a multiwavelength approach (Seyffert et al., 2011). To obtain these constraints we compared the observed radio and $\\gamma$-ray light curves (LCs) for those 6 pulsars by eye to LCs predicted by geometric models detailing the location and extent of emission regions in a pulsar magnetosphere. As a precursor to obtaining these constraints, a parameter study was conducted to reinforce our qualitative understanding of how the underlying model parameters effect the LCs produced by the geometric models. Extracting useful trends from the $\\gamma$-ray model LCs proved difficult though due to the increased complexity of the geometric models for the $\\gamma$-ray emission relative to those for the radio emission. In this paper we explore a second approach to investigating the interplay between the model parameters and the LC atlas. This approach does not attempt to understand how the set of model parameters influences the LC shapes ...

Seyffert, A S; Johnson, T J; Harding, A K

2015-01-01T23:59:59.000Z

118

Two pairing parameters in superconducting grains  

Science Journals Connector (OSTI)

Unlike bulk superconductivity, where one energy scale, the energy gap, characterizes pairing correlations, we show that in small superconducting grains there exist two different such quantities. The first characterizes collective properties of the grain, such as the condensation energy, and the second single-particle properties. To describe these two energy scales, we define two corresponding pairing parameters, and show that although both reduce to the bulk gap for large grains, this occurs at different size scales.

M. Schechter; J. von Delft; Y. Imry; Y. Levinson

2003-02-27T23:59:59.000Z

119

Gamma rays from top-mediated dark matter annihilations  

SciTech Connect

Lines in the energy spectrum of gamma rays are a fascinating experimental signal, which are often considered ''smoking gun'' evidence of dark matter annihilation. The current generation of gamma ray observatories are currently closing in on parameter space of great interest in the context of dark matter which is a thermal relic. We consider theories in which the dark matter's primary connection to the Standard Model is via the top quark, realizing strong gamma ray lines consistent with a thermal relic through the forbidden channel mechanism proposed in the Higgs in Space Model. We consider realistic UV-completions of the Higgs in Space and related theories, and show that a rich structure of observable gamma ray lines is consistent with a thermal relic as well as constraints from dark matter searches and the LHC. Particular attention is paid to the one loop contributions to the continuum gamma rays, which can easily swamp the line signals in some cases, and have been largely overlooked in previous literature.

Jackson, C.B. [University of Texas at Arlington, Arlington, TX 76019 (United States); Servant, Géraldine [CERN Physics Department, Theory Division, CH-1211 Geneva 23 (Switzerland); Shaughnessy, Gabe [Department of Physics, University of Wisconsin, Madison, WI 53706 (United States); Tait, Tim M.P. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Taoso, Marco, E-mail: geraldine.servant@cern.ch, E-mail: chris@uta.edu, E-mail: gshau@hep.wisc.edu, E-mail: ttait@uci.edu, E-mail: marco.taoso@cea.fr [Institut de Physique Théorique, CEA/Saclay, F-91191 Gif-sur-Yvette Cédex (France)

2013-07-01T23:59:59.000Z

120

Gamma ray bursts ROBERT S MACKAY  

E-Print Network (OSTI)

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

Rourke, Colin

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


121

Study Z gamma events and limits on anomalous ZZ gamma and Z gamma gamma couplings in pp(-) collisions at root s=1.96 Tev  

E-Print Network (OSTI)

We present a measurement of the Z gamma production cross section and limits on anomalous ZZ gamma and Z gamma gamma couplings for form-factor scales of Lambda=750 and 1000 GeV. The measurement is based on 138 (152) candidates ...

Baringer, Philip S.; Bean, Alice; Christofek, L.; Coppage, Don; Gardner, J.; Hensel, Carsten; Jabeen, S.; Wilson, Graham Wallace

2005-07-01T23:59:59.000Z

122

The characterization of ice hydrometeor gamma size distributions as volumes in N0-?–? phase space: Implications for microphysical process modeling  

Science Journals Connector (OSTI)

Gamma distributions represent particle size distributions (SDs) in mesoscale and cloud resolving models that predict one, two or three moments of hydrometeor species. They are characterized by intercept (N0), slope (?) and shape (?) parameters ...

Greg M. McFarquhar; Tsung-Lin Hsieh; Matt Freer; Jeana Mascio; Brian F. Jewett

123

{gamma}-RAY LUMINOSITY FUNCTION AND THE CONTRIBUTION TO EXTRAGALACTIC {gamma}-RAY BACKGROUND FOR FERMI-DETECTED BLAZARS  

SciTech Connect

We study {gamma}-ray luminosity functions (GLFs) and the contribution to the extragalactic diffuse {gamma}-rays for blazars. After using a clean blazar sample in which 485 blazars are observed at both the 8.4 GHz and {approx} GeV bands, we investigate the radio/{gamma}-ray luminosity correlation and find out that a strong correlation exists between the radio and {gamma}-ray luminosities using the partial correlation analysis method. Based on such a correlation, we obtain the GLF, while also considering the GLF based on studies of the X-ray luminosity function of active galactic nuclei and the GLF of the EGRET blazars. K-S tests indicate that these three kinds of GLFs are consistent with the observed data of our sample in a reasonable parameter range. Using these GLFs, we further investigate the blazar contribution to the extragalactic diffuse {gamma}-ray background (EGRB). Our results show that (1) the contribution of blazars are {approx}21.3% {+-} 2.7%, {approx}12.9% {+-} 1.7%, and {approx}37.9% {+-} 4.8% of unresolved Fermi EGRB flux for the three GLFs and (2) the contribution of flat-spectrum radio quasars are {approx}11.2% {+-} 1.6%, {approx}6.9% {+-} 1.0%, and {approx}9.0% {+-} 1.2% of unresolved Fermi EGRB flux for the three GLFs.

Zeng, H. D.; Yan, D. H.; Sun, Y. Q.; Zhang, L., E-mail: lizhang@ynu.edu.cn [Department of Physics, Yunnan University, Kunming (China)

2012-04-20T23:59:59.000Z

124

Photon Source Parameters  

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

Photon Source Parameters Photon Source Parameters Photon Source Parameters Print Summary Graph of Brightness Curves for All Insertion Devices Insertion Device and Bend Magnet Parameters Bend Magnet Superbend Magnet U30 Undulator U50 Undulator U80 Undulator U100 Undulator W114 Wiggler The ALS has six elliptically polarizing undulators, two in straight 4, two in straight 11, and one each in straights 6 and 7. All are arranged with chicanes so that two such devices can be installed to feed two independent beamlines. They can be used in a variety of polarization modes, including circular, elliptical, horizontal, and vertical. These modes can be chosen by appropriate phasing of the magnet rows. The brightness and flux curves below are shown for horizontal and circular polarization. Curves for elliptical and vertical polarization are similar to the horizontal polarization curve, but the minimum photon energy is higher.

125

Office of Standards and Quality Assurance Correspondence | Department of  

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

Services » Program Management » Quality Assurance » Office of Services » Program Management » Quality Assurance » Office of Standards and Quality Assurance Correspondence Office of Standards and Quality Assurance Correspondence The Safety and Security Program (EM-20) and subsequently the Office of Standards and Quality Assurance (EM-23) place a large emphasis on the fact that the Environmental Management (EM) work of safely cleaning up the environmental legacy of the Cold War is performed in the Field. A primary role of our Headquarters (HQ) office is assisting the Field to achieve mission success and recognizing that we are accountable for the quality, timeliness, and efficiency of our efforts, products, and support to the Field. EM-23 also embraces the EM Business Model which emphasizes completing these support functions in a proactive manner, not simply identifying issues.

126

Archived EM SSAB Correspondence & Briefings | Department of Energy  

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

Archived EM Archived EM SSAB Correspondence & Briefings Archived EM SSAB Correspondence & Briefings 2006 June 21, 2006 Letter: Congratulating Oak Ridge SSAB and its Stewardship Committee for Receiving the EPA's 2006 Citizen's Excellence in Community Involvement Award From: Assistant Secretary for Environmental Management, James A. Rispoli To: Mr. Kerry Trammell, Chair Site Specific Advisory Board 2004 March 9, 2004 Letter: Transition of Closure Sites from the Office of Environmental Management to other DOE Organizations From: Deputy Secretary of Energy, Kyle E. McSlarrow (DS-1) To: Todd Martin, Chair, Hanford Advisory Board 2003 December 22, 2003 Letter: Progress in Implementing a Direct DOE Relationship & Funding for the EMSSABs From: Assistant Secretary, Jessie H. Roberson (EM-1)

127

Modeling gamma-ray bursts.  

E-Print Network (OSTI)

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

Maxham, Amanda

2011-01-01T23:59:59.000Z

128

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

SciTech Connect

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.

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

129

Gamma radiation field intensity meter  

DOE Patents (OSTI)

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.

Thacker, L.H.

1995-10-17T23:59:59.000Z

130

Gamma radiation field intensity meter  

DOE Patents (OSTI)

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.

Thacker, L.H.

1994-08-16T23:59:59.000Z

131

Gamma radiation field intensity meter  

DOE Patents (OSTI)

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.

Thacker, Louis H. (Knoxville, TN)

1995-01-01T23:59:59.000Z

132

Gamma radiation field intensity meter  

DOE Patents (OSTI)

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.

Thacker, Louis H. (Knoxville, TN)

1994-01-01T23:59:59.000Z

133

On the possible effects of gluon number fluctuations on {gamma}{gamma} collisions at high energies  

SciTech Connect

We investigate the effects of the fluctuations on the total {gamma}{gamma}, {gamma}*{gamma}* cross sections and the real photon structure function F{sup {gamma}}{sub 2}(x,Q{sup 2}), considering a saturation phenomenological model for the dipole-dipole cross section and scattering amplitude with fluctuations included.

Goncalves, V. P.; De Santana Amaral, J. T. [Instituto de Fisica e Matematica, Universidade Federal de Pelotas, Caixa Postal 354, 96010-900, Pelotas, RS (Brazil)

2013-03-25T23:59:59.000Z

134

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

E-Print Network (OSTI)

Gamma-RayGamma-Ray Bursts: from SwiftBursts: from Swift to GLASTto GLAST Bing ZhangBing ZhangGehrels, et al), et al) #12;Gamma-ray bursts: the mostGamma-ray bursts: the most violent explosions fireball central photosphere internal external shocks engine (shocks) (reverse) (forward) gamma-ray UV

California at Santa Cruz, University of

135

Impact parameter dependent color glass condensate dipole model  

SciTech Connect

We show that the color glass condensate dipole model of Iancu, Itakura, and Munier, improved to include the impact parameter dependence, gives a good fit to the total {gamma}*p cross section measured at HERA if the anomalous dimension at the saturation scale, {gamma}{sub s}, is treated as a free parameter. We find that the optimum value of {gamma}{sub s}=0.46 is close to the value determined from numerical solution of the Balitsky-Kovchegov equation. The impact parameter dependent saturation scale is generally less than 0.5 GeV{sup 2} in the HERA kinematic regime for the most relevant impact parameters b{approx}2-3 GeV{sup -1}. We compare predictions of the model to data on the longitudinal and heavy flavour structure functions, exclusive diffractive vector meson production, and deeply virtual Compton scattering at HERA. The model is found to be deficient for observables sensitive to moderately small dipole sizes, where an alternative model with explicit Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution performs better. The energy dependence of exclusive diffractive processes is shown to provide an important discriminator between different dipole model cross sections.

Watt, G. [Department of Physics and Astronomy, University College London, WC1E 6BT (United Kingdom); Kowalski, H. [Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg (Germany)

2008-07-01T23:59:59.000Z

136

Olive bagasse and nutshell as gamma shielding material  

SciTech Connect

Gamma ray linear attenuation coefficients have been measured experimentally for olive bagasse and nutshell by using narrow beam geometry for Co-60 and the values have been compared with soil. These values have been used calculate mean free path, half value layer and tenth value layer parameters. Besides, effect of multi-layered systems (soil + olive bagasse and soil + nutshell) has been analyzed in terms of half value layer.

?naç, Esra; Bayta?, A. Filiz [Energy Institute, Istanbul Technical University, 34469 Istanbul (Turkey)

2013-12-16T23:59:59.000Z

137

Short Gamma-Ray Bursts from Binary Neutron Star Mergers  

E-Print Network (OSTI)

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.

Roland Oechslin; Thomas Janka

2006-04-27T23:59:59.000Z

138

Using a scalar parameter to trace dislocation evolution in atomistic modeling  

SciTech Connect

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.

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

139

Gamma ray lines: what will they tell us about SUSY?  

E-Print Network (OSTI)

Neutralino dark matter can be indirectly detected by observing the gamma ray lines from the annihilation processes XX-->gg and XX-->gZ. In this paper we study the implications that the observation of these two lines could have for the determination of the supersymmetric parameter space. Within the minimal supergravity framework, we find that, independently of the dark matter distribution in the Galaxy, such observations by themselves would allow to differentiate between the coannihilation region, the funnel region, and the focus point region. As a result, several restrictions on the msugra parameters can be derived. Within a more general MSSM scenario, we show that the observation of gamma-ray lines might be used to discriminate between a bino-, a wino-, and a higgsino-like neutralino, with important consequences for cosmology and for models of supersymmetry breaking. The detection of the gamma ray lines, therefore, will not only provide an unmistakable signature of dark matter, it will also open a new road toward the determination of supersymmetric parameters.

Carlos E. Yaguna

2009-09-23T23:59:59.000Z

140

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

E-Print Network (OSTI)

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.

Yanping , Huang; The ATLAS collaboration

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma parameter corresponds" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


141

Parameter Estimation Through Ignorance  

E-Print Network (OSTI)

Dynamical modelling lies at the heart of our understanding of physical systems. Its role in science is deeper than mere operational forecasting, in that it allows us to evaluate the adequacy of the mathematical structure of our models. Despite the importance of model parameters, there is no general method of parameter estimation outside linear systems. A new relatively simple method of parameter estimation for nonlinear systems is presented, based on variations in the accuracy of probability forecasts. It is illustrated on the Logistic Map, the Henon Map and the 12-D Lorenz96 flow, and its ability to outperform linear least squares in these systems is explored at various noise levels and sampling rates. As expected, it is more effective when the forecast error distributions are non-Gaussian. The new method selects parameter values by minimizing a proper, local skill score for continuous probability forecasts as a function of the parameter values. This new approach is easier to implement in practice than alternative nonlinear methods based on the geometry of attractors or the ability of the model to shadow the observations. New direct measures of inadequacy in the model, the "Implied Ignorance" and the information deficit are introduced.

Hailiang Du; Leonard A. Smith

2012-06-06T23:59:59.000Z

142

Photon Source Parameters  

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

Photon Source Parameters Print Photon Source Parameters Print Summary Graph of Brightness Curves for All Insertion Devices Insertion Device and Bend Magnet Parameters Bend Magnet Superbend Magnet U30 Undulator U50 Undulator U80 Undulator U100 Undulator W114 Wiggler The ALS has six elliptically polarizing undulators, two in straight 4, two in straight 11, and one each in straights 6 and 7. All are arranged with chicanes so that two such devices can be installed to feed two independent beamlines. They can be used in a variety of polarization modes, including circular, elliptical, horizontal, and vertical. These modes can be chosen by appropriate phasing of the magnet rows. The brightness and flux curves below are shown for horizontal and circular polarization. Curves for elliptical and vertical polarization are similar to the horizontal polarization curve, but the minimum photon energy is higher.

143

Photon Source Parameters  

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

Photon Source Parameters Print Photon Source Parameters Print Summary Graph of Brightness Curves for All Insertion Devices Insertion Device and Bend Magnet Parameters Bend Magnet Superbend Magnet U30 Undulator U50 Undulator U80 Undulator U100 Undulator W114 Wiggler The ALS has six elliptically polarizing undulators, two in straight 4, two in straight 11, and one each in straights 6 and 7. All are arranged with chicanes so that two such devices can be installed to feed two independent beamlines. They can be used in a variety of polarization modes, including circular, elliptical, horizontal, and vertical. These modes can be chosen by appropriate phasing of the magnet rows. The brightness and flux curves below are shown for horizontal and circular polarization. Curves for elliptical and vertical polarization are similar to the horizontal polarization curve, but the minimum photon energy is higher.

144

Photon Source Parameters  

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

Photon Source Parameters Print Photon Source Parameters Print Summary Graph of Brightness Curves for All Insertion Devices Insertion Device and Bend Magnet Parameters Bend Magnet Superbend Magnet U30 Undulator U50 Undulator U80 Undulator U100 Undulator W114 Wiggler The ALS has six elliptically polarizing undulators, two in straight 4, two in straight 11, and one each in straights 6 and 7. All are arranged with chicanes so that two such devices can be installed to feed two independent beamlines. They can be used in a variety of polarization modes, including circular, elliptical, horizontal, and vertical. These modes can be chosen by appropriate phasing of the magnet rows. The brightness and flux curves below are shown for horizontal and circular polarization. Curves for elliptical and vertical polarization are similar to the horizontal polarization curve, but the minimum photon energy is higher.

145

Photon Source Parameters  

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

Photon Source Parameters Print Photon Source Parameters Print Summary Graph of Brightness Curves for All Insertion Devices Insertion Device and Bend Magnet Parameters Bend Magnet Superbend Magnet U30 Undulator U50 Undulator U80 Undulator U100 Undulator W114 Wiggler The ALS has six elliptically polarizing undulators, two in straight 4, two in straight 11, and one each in straights 6 and 7. All are arranged with chicanes so that two such devices can be installed to feed two independent beamlines. They can be used in a variety of polarization modes, including circular, elliptical, horizontal, and vertical. These modes can be chosen by appropriate phasing of the magnet rows. The brightness and flux curves below are shown for horizontal and circular polarization. Curves for elliptical and vertical polarization are similar to the horizontal polarization curve, but the minimum photon energy is higher.

146

Towards the correspondence between Q-clouds and sphalerons  

E-Print Network (OSTI)

Non-linear classical equations of motion may admit degenerate solutions at fixed charges. While the solutions with lower energies are classically stable, the ones with larger energies are unstable and refereed as Q-clouds. We consider a theory in which the homogeneous charged condensate is classically stable and argue that Q-clouds correspond to sphalerons between the stable Q-balls and the condensate. For the model with analytic solution, we present Arrhenius formula for the quantum production of Q-balls from the condensate at large temperatures.

Nugaev, Emin

2015-01-01T23:59:59.000Z

147

AdS/CFT correspondence beyond its supergravity approximation  

E-Print Network (OSTI)

We will study the AdS/CFT correspondence beyond its supergravity approximation by deforming an effective field theory on AdS by string length scale effects. We will explicitly show that the conformal dimensions of both the relevant and the irrelevant operators receive correction from these string theory effects going beyond its supergravity approximation. However, as is expected from the full string theory on AdS (not just its supergravity approximation) being dual to the $\\mathcal{N}=4$ super-Yang-Mills theory, the conformal dimension of marginal operators do not receive any such corrections.

Mir Faizal; Ahmed Farag Ali; Ali Nassar

2014-05-18T23:59:59.000Z

148

Digital discrimination of neutrons and gamma-rays in organic scintillation detectors using moment analysis  

SciTech Connect

Digital discrimination of neutron and gamma-ray events in an organic scintillator has been investigated by moment analysis. Signals induced by an americium-beryllium (Am/Be) isotropic neutron source in a stilbene crystal detector have been sampled with a flash analogue-to-digital converter (ADC) of 1 GSamples/s sampling rate and 10-bit vertical resolution. Neutrons and gamma-rays have been successfully discriminated with a threshold corresponding to gamma-ray energy about 217 keV. Moment analysis has also been verified against the results assessed by a time-of-flight (TOF) measurement. It is shown that the classification of neutrons and gamma-rays afforded by moment analysis is consistent with that achieved by digital TOF measurement. This method has been applied to analyze the data acquired from the stilbene crystal detector in mixed radiation field of the HL-2A tokamak deuterium plasma discharges and the results are described.

Xie Xufei; Zhang Xing; Yuan Xi; Chen Jinxiang; Li Xiangqing; Zhang Guohui; Fan Tieshuan [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing (China); Yuan Guoliang; Yang Jinwei; Yang Qingwei [Southwestern Institute of Physics, Chengdu (China)

2012-09-15T23:59:59.000Z

149

Dissecting the Gamma-Ray Background in Search of Dark Matter  

E-Print Network (OSTI)

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.

Ilias Cholis; Dan Hooper; Samuel D. McDermott

2013-12-02T23:59:59.000Z

150

AGATA - Advanced Gamma Tracking Array  

E-Print Network (OSTI)

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.

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. Duchêne; 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

2011-11-24T23:59:59.000Z

151

Gamma Industry Processing Alliance Overview | Department of Energy  

Office of Environmental Management (EM)

Gamma Industry Processing Alliance Overview Gamma Industry Processing Alliance Overview Gamma Industry Processing Alliance Overview More Documents & Publications 2011 NTSF Meeting...

152

Gamma ray bursts: The future  

Science Journals Connector (OSTI)

Gamma-ray bursts are the most dramatic and powerful cosmic explosions known. They also continue to be the most puzzling. Thanks to breakthrough observations over the last decade however a picture has emerged of gamma-ray bursts being at cosmological distances and capable of releasing more than 10 51 ergs of energy within seconds. Despite the emergence of this picture the physical origin of bursts is still unknown and the classification of different types of bursts is still in its infancy. Further understanding of gamma-ray bursts requires the wise use of our current resources and the development of new observational capabilities. We outline the current state of our knowledge of bursts and describe the present and future instrumentation which will enable us to understand these baffling blasts.

N. Gehrels; D. Macomb

2000-01-01T23:59:59.000Z

153

Quasipotential Equation Corresponding to the Relativistic Eikonal Approximation  

Science Journals Connector (OSTI)

A three-dimensional Lippmann-Schwinger-type equation for the elastic scattering amplitude and the corresponding homogeneous Schrödinger equation for the two-particle bound states are studied. The potential is defined as an infinite power series in the coupling constant which fits the perturbative expansion of the on-energy-shell scattering amplitude. The approximate equation obtained by keeping only the lowest-order term in the potential is local and has the following properties: (i) The scattering amplitude yields the relativistic eikonal approximation for large energies or small exchanged mass and momentum transfer; (ii) for the Coulomb problem the approximate equation is exactly soluble and leads to a relativistic Balmer formula including the fine-structure splitting.

I. T. Todorov

1971-05-15T23:59:59.000Z

154

Gravitational Correspondence of Two Types of Superconformal Anomaly  

E-Print Network (OSTI)

In a classical conformal invariant supersymmetric gauge theory, the chiral R-symmetry current, the supersymmetry current and the energy-momentum tensor constitute a supercurrent multiplet. There are two different superconformal anoamly multiplets in four-dimensional supersymmetric gauge theories, one originating from the supersymmetric gauge dynamics and the consequent nonvanishing \\beta-function, and the other one coming from the coupling of the supercurrent multiplet to the external supergravity multiplet with non-trivial topology. We emphasize that in the gauge/gravity dual correspondence these two types of superconformal anomaly multiplets have distinct reflections in the classical supergravity: the anomaly multiplet due to the supersymmetry gauge dynamics is dual to the spontaneous symmetry breaking and the consequent super-Higgs effect in AdS_5 bulk supergravity, while the anomaly multiplet originating from the non-trivial topology of external conformal supergravity mutiplet is a boundary effects of the AdS_5 space.

W. F. Chen

2006-04-23T23:59:59.000Z

155

Neutrinos from Gamma Ray Bursts  

E-Print Network (OSTI)

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

F. Halzen; G. Jaczko

1996-02-07T23:59:59.000Z

156

sin 2 beta + gamma Measurements  

SciTech Connect

I report on the most recent measurements done to constrain sin(2{beta}+{gamma}) with neutral B mesons. Direct measurements of 2{beta} + {gamma} will provide a precise test of the standard model predictions with higher statistics. Present constraints come from studies of B {yields} D{sup (*){+-}}{pi}{sup {-+}}/{rho}{sup {-+}} decays done by BABAR and Belle collaborations with full and inclusive techniques to reconstruct B mesons. B {yields} D{sup 0(*)}K{sup 0} decays are also very promising but statistics are too low to give any constraint at the moment.

Therin, G; /Paris U., VI-VII

2005-06-24T23:59:59.000Z

157

Gamma-ray Imaging Methods  

SciTech Connect

In this document we discuss specific implementations for gamma-ray imaging instruments including the principle of operation and describe systems which have been built and demonstrated as well as systems currently under development. There are several fundamentally different technologies each with specific operational requirements and performance trade offs. We provide an overview of the different gamma-ray imaging techniques and briefly discuss challenges and limitations associated with each modality (in the appendix we give detailed descriptions of specific implementations for many of these technologies). In Section 3 we summarize the performance and operational aspects in tabular form as an aid for comparing technologies and mapping technologies to potential applications.

Vetter, K; Mihailescu, L; Nelson, K; Valentine, J; Wright, D

2006-10-05T23:59:59.000Z

158

BNL | ATF Beamline Parameters  

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

Beamline Parameters Beamline Parameters Electron beam energy: 25 to 76 MeV Temporal structure: Macropulse length: 3 microseconds Macropulse repetition rate from under 1 PPS to 3 PPS. Micropulse repetition period 12.25 ns or 24.5 ns. Micropulse length variable from about 1 ps FWHM to 10 ps FWHM. Electron beam charge: continuously variable. Single micropulse charge from zero to a few nanoculombs. Bunch train charge up to about 10 nanoculombs. Emittance: depends on various conditions, e.g. peak current, gun field, microbunch length etc. At 1 nC we have measured the emittance at 2.6 mm mrad (rms normalized) at a bunch length of 10 ps FWHM. The local emittance (Slice Emittance) is smaller, measured 1.4 mm mrad for a slice out of the 1 nC bunch. Stability: (approx.) 1 ps in short term phase, 1% of beam diameter

159

Measurements of B to V(Gamma) Decays  

SciTech Connect

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.

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

2010-09-02T23:59:59.000Z

160

Essay on the gamma ray laser  

E-Print Network (OSTI)

This work discusses the possibility of inducing the emission of gamma radiation from nuclear isomers by two-photon transitions, in the more general context of the problem of the amplification of gamma radiation.

Silviu Olariu

1999-07-18T23:59:59.000Z

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


161

Testing scalar-tensor theories and PPN parameters in Earth orbit  

E-Print Network (OSTI)

We compute the PPN parameters $\\gamma$ and $\\beta$ for general scalar-tensor theories in the Einstein frame, which we compare to the existing PPN formulation in the Jordan frame for alternative theories of gravity. This computation is important for scalar-tensor theories that are expressed in the Einstein frame, such as chameleon and symmetron theories, which can incorporate hiding mechanisms that predict environment-dependent PPN parameters. We introduce a general formalism for scalar-tensor theories and constrain it using the limit on $\\gamma$ given by the Cassini experiment. In particular we discuss massive Brans-Dicke scalar fields for extended sources. Next, using a recently proposed Earth satellite experiment, in which atomic clocks are used for spacecraft tracking, we compute the observable perturbations in the redshift induced by PPN parameters deviating from their general relativistic values. Our estimates suggest that $|\\gamma - 1| \\sim |\\beta -1| \\sim 10^{-6}$ may be detectable by a satellite that ...

Schärer, Andreas; Bondarescu, Ruxandra; Jetzer, Philippe; Lundgren, Andrew

2014-01-01T23:59:59.000Z

162

Single-parameter pumping in graphene  

Science Journals Connector (OSTI)

We propose a quantum pump mechanism based on the particular properties of graphene, namely chirality and bipolarity. The underlying physics is the excitation of evanescent modes entering a potential barrier from one lead, while those from the other lead do not reach the driving region. This induces a large nonequilibrium current with electrons stemming from a broad range of energies, in contrast to the narrow resonances that govern the corresponding effect in semiconductor heterostructures. Moreover, the pump mechanism in graphene turns out to be robust, with a simple parameter dependence, which is beneficial for applications. Numerical results from a Floquet scattering formalism are complemented with analytical solutions for small to moderate driving.

Pablo San-Jose; Elsa Prada; Sigmund Kohler; Henning Schomerus

2011-10-11T23:59:59.000Z

163

The Diverse Environments of Gamma-Ray Bursts  

E-Print Network (OSTI)

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

Perley, Daniel Alan

2011-01-01T23:59:59.000Z

164

Pulsed Gamma-Ray-Burst Afterglows  

E-Print Network (OSTI)

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

J. Middleditch

2009-01-01T23:59:59.000Z

165

Light Curves of Swift Gamma Ray Bursts  

E-Print Network (OSTI)

Recent observations from the Swift gamma-ray burst mission indicate that a fraction of gamma ray bursts are characterized by a canonical behaviour of the X-ray afterglows. We present an effective theory which allows us to account for X-ray light curves of both (short - long) gamma ray bursts and X-ray rich flashes. We propose that gamma ray bursts originate from massive magnetic powered pulsars.

Paolo Cea

2006-09-22T23:59:59.000Z

166

Periodicities in gamma ray bursts  

Science Journals Connector (OSTI)

Gamma ray burst models based on magnetic neutron stars face a problem of account for the scarcity of observed periods. Both this scarcity and the typical period found when any is detected are explained if the neutron stars are accreting in binary systems

Kent S. Wood

1984-01-01T23:59:59.000Z

167

Gamma-ray events thunderclouds  

E-Print Network (OSTI)

stage of rocket-triggered lightning #12;The gamma-ray flash occurred at the same time the upward leader radiation is also produced by natural lightning during the stepped leader phase. · Dwyer et al. 2003, 2004 found that x-rays are also produced by triggered lightning dart leaders. · At present, the only viable

California at Berkeley, University of

168

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

E-Print Network (OSTI)

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

Enomoto, Ryoji

169

Very high-energy gamma rays from gamma-ray bursts  

Science Journals Connector (OSTI)

...research-article Discussion Meeting Issue Gamma-ray bursts organized by Alan Wells, Ralph...high-energy gamma rays from gamma-ray bursts Paula M Chadwick * * ( p.m...progress makes the detection of a gamma-ray burst at the highest energies much...

2007-01-01T23:59:59.000Z

170

A proof of the Gamma test  

Science Journals Connector (OSTI)

...research-article Research Article A proof of the Gamma test Dafydd Evans Antonia J. Jones Department...dataset of input-output vectors, the Gamma test estimates the variance of the noise on...derivatives. We present a proof of the Gamma test under fairly weak hypotheses. nonlinear...

2002-01-01T23:59:59.000Z

171

Gamma-ray burst theory after Swift  

Science Journals Connector (OSTI)

...research-article Discussion Meeting Issue Gamma-ray bursts organized by Alan Wells, Ralph...J. Wijers and Martin Rees Gamma-ray burst theory after Swift Tsvi Piran...relativistic blast wave model for gamma-ray bursts (GRBs). Together with the...

2007-01-01T23:59:59.000Z

172

Gamma-ray bursts and cosmology  

Science Journals Connector (OSTI)

...research-article Discussion Meeting Issue Gamma-ray bursts organized by Alan Wells, Ralph...J. Wijers and Martin Rees Gamma-ray bursts and cosmology D.Q Lamb...current status of the use of gamma-ray bursts (GRBs) as probes of the early...

2007-01-01T23:59:59.000Z

173

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

SciTech Connect

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)

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

174

Correlations with gamma?ray bursts  

Science Journals Connector (OSTI)

We performed correlation function analyses involving the first 260 BATSE detected gamma?ray bursts (GRBs) searching for evidence of bunching or repetition. The BATSE GRB two?point angular auto?correlation function shows excesses at small and high angles as noted previously by Quashnock and Lamb (1993) and Narayan and Piran (1993). The BATSE GRB two?point temporal correlation function shows no significant excesses at any times but does show a significant dip on the time scale of hours. This dip is real and corresponds to BATSE ignoring dim bursts while processing bright bursts. Even when constrained to bursts with recorded angular separations less than 20° no temporal excess is found. Therefore if GRBs repeat this analysis was unable to locate any obvious repetition timescale. We have computed the general GRB?Abell cluster angular cross?correlation function and again find no significant peaks. In sum the times and positions of the first 260 GRBs released into the public domain show no significant evidence in our opinion the GRBs correlate with themselves or Abell clusters.

Robert J. Nemiroff; Gabriela F. Marani; Juan R. Cebral; Jay P. Norris

1994-01-01T23:59:59.000Z

175

THE BATSE 5B GAMMA-RAY BURST SPECTRAL CATALOG  

SciTech Connect

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)

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

176

Solar gamma rays powered by secluded dark matter  

SciTech Connect

Secluded dark matter models, in which weakly interacting massive particles 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.

Batell, Brian; Shang Yanwen [Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2J 2W9 (Canada); Pospelov, Maxim [Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2J 2W9 (Canada); Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, V8P 1A1 (Canada); Ritz, Adam [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia, V8P 1A1 (Canada)

2010-04-01T23:59:59.000Z

177

Gamma-ray identification of nuclear weapon materials  

SciTech Connect

There has been an accelerating national interest in countering nuclear smuggling. This has caused a corresponding expansion of interest in the use of gamma-ray spectrometers for checkpoint monitoring, nuclear search, and within networks of nuclear and collateral sensors. All of these are fieldable instruments--ranging from large, fixed portal monitors to hand-held and remote monitoring equipment. For operational reasons, detectors with widely varying energy resolution and detection efficiency will be employed. In many instances, such instruments must be sensitive to weak signals, always capable of recognizing the gamma-ray signatures from nuclear weapons materials (NWM), often largely insensitive to spectral alteration by radiation transport through intervening materials, capable of real-time implementation, and able to discriminate against signals from commonly encountered legitimate gamma-ray sources, such as radiopharmaceuticals. Several decades of experience in classified programs have shown that all of these properties are not easily achieved and successful approaches were of limited scope--such as the detection of plutonium only. This project was originally planned as a two-year LDRD-ER. Since funding for 1997 was not sustained, this is a report of the first year's progress.

Gosnell, T. B., LLNL; Hall, J. M.; Jam, C. L.; Knapp, D. A.; Koenig, Z. M.; Luke, S. J.; Pohl, B. A.; Schach von Wittenau, A.; Wolford, J. K.

1997-02-03T23:59:59.000Z

178

Parameter Estimation of the Hybrid Censored Log-Normal Distribution  

E-Print Network (OSTI)

, Pin 560035, India. SQC & OR Unit, Indian Statistical Institute, 203 B.T. Road, Kolkata, Pin 700108, India. Corresponding author, e-mail: bis@isical.ac.in Department of Mathematics and Statistics, Indian of the exponential parameter. Drapper and Guttmann [7] also considered the same problem but from the Bayesian point

Kundu, Debasis

179

Electrochromic Glazings: Animation Parameters  

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

Glazings Glazings Animation Simulation Parameters The Electrochromic Glazing Office Animation is created using an image compositing method whereby separate images of the office generated with only one source of illumination are added together in variable percentages to come up with the final image. This method assumes that the sources of illumination do not change position through the animation sequence. Although the sun does move approximately 5 degrees during the span of this 20 minute animation sequence, because this movement is not the focus of the simulation and does not significantly change the intensity of the solar exposure, it is ignored. This method takes advantage of the principal of the scalability of light to avoid the significant time involved in calculating separate Radiance renderings for each combination of sky condition (direct sun versus no direct sun) and electrochromic glazing transmission.

180

Sandia National Laboratories: Research: Facilities: Gamma Irradiation  

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

Gamma Irradiation Facility Gamma Irradiation Facility Photo of Gamma Irradiation Facility The Gamma Irradiation Facility (GIF) provides high-fidelity simulation of nuclear radiation environments for materials and component testing. The low-dose irradiation facility also offers an environment for long-duration testing of materials and electronic components. Such testing may take place over a number of months or even years. Research and other activities The single-structure GIF can house a wide variety of gamma irradiation experiments with various test configurations and at different dose and dose rate levels. Radiation fields at the GIF are produced by high-intensity gamma-ray sources. To induce ionizing radiation effects and damage in test objects, the objects are subjected to high-energy photons from gamma-source

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


181

Definition: Gamma Log | Open Energy Information  

Open Energy Info (EERE)

Definition Definition Edit with form History Facebook icon Twitter icon » Definition: Gamma Log Jump to: navigation, search Dictionary.png Gamma Log Gamma logging is a method of measuring naturally occurring gamma radiation to characterize the rock or sediment in a borehole or drill hole. It is a wireline logging method used in mining, mineral exploration, water-well drilling, for formation evaluation in oil and gas well drilling and for other related purposes. Different types of rock emit different amounts and different spectra of natural gamma radiation.[1] View on Wikipedia Wikipedia Definition Gamma ray logging is a method of measuring naturally occurring gamma radiation to characterize the rock or sediment in a borehole or drill hole. It is a wireline logging method used in mining, mineral exploration,

182

Gamma radiolysis of chlorinated hydrocarbons  

SciTech Connect

This program is the Idaho National Engineering Laboratory (INEL) component of a joint collarborative effort with Lawrence Livermore National Laboratory (LLNL). The purpose of this effort is to demonstrate a viable process for breaking down hazardous halogenated organic wastes to simpler, non-hazardous waste using high energy ionizing radiation. The INEL effort focuses on the use of spent reactor fuel gamma radiation sources to decompose complex wastes such as PCBs. At LLNL, halogenated solvents such as carbon tetrachloride and trichloroethylene are being studied using accelerator radiation sources. The INEL irradiation experiments concentrated on a single PCB congener so that a limited set of decomposition reactions could be studied. The congener 2,2{prime}, 3,3{prime},4,5{prime},6,6{prime} - octachlorobiphenyl was examined following exposure to various gamma doses at the Advanced Test Reactor (AIR) spent fuel pool. The decomposition rates and products in several solvents are discussed. 3 refs.

Arbon, R.E.; Mincher, B.J.; Meikrantz, D.H.

1992-01-01T23:59:59.000Z

183

Gamma radiolysis of chlorinated hydrocarbons  

SciTech Connect

This program is the Idaho National Engineering Laboratory (INEL) component of a joint collarborative effort with Lawrence Livermore National Laboratory (LLNL). The purpose of this effort is to demonstrate a viable process for breaking down hazardous halogenated organic wastes to simpler, non-hazardous waste using high energy ionizing radiation. The INEL effort focuses on the use of spent reactor fuel gamma radiation sources to decompose complex wastes such as PCBs. At LLNL, halogenated solvents such as carbon tetrachloride and trichloroethylene are being studied using accelerator radiation sources. The INEL irradiation experiments concentrated on a single PCB congener so that a limited set of decomposition reactions could be studied. The congener 2,2{prime}, 3,3{prime},4,5{prime},6,6{prime} - octachlorobiphenyl was examined following exposure to various gamma doses at the Advanced Test Reactor (AIR) spent fuel pool. The decomposition rates and products in several solvents are discussed. 3 refs.

Arbon, R.E.; Mincher, B.J.; Meikrantz, D.H.

1992-08-01T23:59:59.000Z

184

Gamma Industry Processing Alliance Overview  

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

NATIONAL NATIONAL STAKEHOLDERS TRANSPORTATION FORUM WHO IS GIPA? * Alliance made up of 15 companies from the Medical Device Manufacturers, Cobalt source , manufacturers and one industrial processing company Represents all the major gamma processing * Represents all the major gamma processing facilities within the US to the regulatory bodies such as the USNRC. * Member of International Irradiation Association (iiA) WHO IS GIPA? An alliance created to advocate the development of An alliance created to advocate the development of responsible regulations that enhance the safe and secure management of Cobalt-60 sources and related irradiation processing facilities related irradiation processing facilities. APRIL 15, 2010 PRESENTATION TITLE WORLD SUPPLIERS OF COBALT 60 COBALT 60 * Nordion Inc

185

Are gamma ray bursts nearby?  

Science Journals Connector (OSTI)

The possibility is considered that the intrinsic luminosity function of gamma ray bursters has sufficient scatter that the ln?N?ln?S relation of observed bursts not be dominated by geometric effects favoring large volumes but rather be dominated by nearby intrinsically faint bursts. It is shown that the distribution of bursts on the sky would be very granular with a significant fraction of them coming from the two or three nearest sources. Possible solutions and alternatives are briefly discussed.

David Eichler

1994-01-01T23:59:59.000Z

186

Gamma-ray burst afterglows  

E-Print Network (OSTI)

Extended, fading emissions in multi-wavelength are observed following Gamma-ray bursts (GRBs). Recent broad-band observational campaigns led by the Swift Observatory reveal rich features of these GRB afterglows. Here we review the latest observational progress and discuss the theoretical implications for understanding the central engine, composition, and geometric configuration of GRB jets, as well as their interactions with the ambient medium.

Bing Zhang

2006-11-24T23:59:59.000Z

187

Neutrinos from Gamma Ray Bursts  

Science Journals Connector (OSTI)

The observed fluxes of cosmic rays and gamma rays are used to infer the maximum allowed high-energy neutrino flux allowed for Gamma Ray Bursts (GRBs) following Reference [1]. 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-?2000 limit on isotropic neutrinos. This could have two implications either GRBs do not produce the ultrahigh energy cosmic rays [2 3] or that the GRBs are strongly beamed and emit most of their power at energies well above 100 GeV [4] implausibly increasing the energy requirements but consistent with the marginal detections of a few low-redshift GRBs by MILAGRITO [5] HEGRA-AIROBICC [6] and the Tibet-Array [7]. All crucial measurements to test the models will be available in the next few years. These are measurements of (i) high-energy neutrinos with AMANDA-ICECUBE or an enlarged ANTARES/NESTOR ocean detector (ii) GRB redshifts from HETE-2 follow-up studies and (iii) GRB spectra above 10 GeV with low-threshold imaging air Cherenkov telescopes such as MAGIC and the space telescopes AGILE and GLAST.

Karl Mannheim

2001-01-01T23:59:59.000Z

188

Neutrinos from Gamma Ray Bursts  

E-Print Network (OSTI)

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

Karl Mannheim

2000-10-18T23:59:59.000Z

189

Search for CP violating signature of intergalactic magnetic helicity in the gamma-ray sky  

Science Journals Connector (OSTI)

......equation (1) is given in terms of the energies, with...have an interpretation in terms of cascade gamma-rays...parameters kappa and z s that enter equation (3), and also...can also be explained in terms of magnetic field structures...wiki/index.php/Search_for_CP_violation......

Hiroyuki Tashiro; Wenlei Chen; Francesc Ferrer; Tanmay Vachaspati

2014-01-01T23:59:59.000Z

190

GeV Emission from Collisional Magnetized Gamma Ray Bursts  

E-Print Network (OSTI)

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.

P. Mészáros; M. J. Rees

2011-04-26T23:59:59.000Z

191

Gamma-ray free-electron lasers: Quantum fluid model  

E-Print Network (OSTI)

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.

Silva, H M

2014-01-01T23:59:59.000Z

192

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

E-Print Network (OSTI)

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.

M. Aslam Chaudhry

1998-11-06T23:59:59.000Z

193

Mouse Strain-Dependent Variations in Sensitivity to Induction of Gamma-H2AX  

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

Mouse Strain-Dependent Variations in Sensitivity to Induction of Gamma-H2AX Mouse Strain-Dependent Variations in Sensitivity to Induction of Gamma-H2AX Foci after Continuous Low Dose-Rate Irradiation: The Atm-/- vs Atm +/+ genotypes on Balb/c, 129S6, C57BL/6J, and A/J inbred strains J.R. Brogan Colorado State University Abstract We have recently developed a ‘low dose rate’ gamma-H2AX assay that is sufficiently sensitive to distinguish differences in response for cells from normal Atm +/+ (mouse) or ATM+/+ (human) and the phenotypes associated with the corresponding heterozygous genotypes(1, 2). The assay is also capable of distinguishing mild hypersensitivities for cells from an appreciable proportion of apparently normal individuals(3). We used this assay to determine whether the genetic background of four commonly used

194

Reduction of Quark Mass Scheme Dependence in B bar -> Xs gamma at the NNLL Level  

SciTech Connect

The uncertainty of the theoretical prediction of the B {yields} X{sub s}{gamma} branching ratio at NLL level is dominated by the charm mass renormalization scheme ambiguity. In this paper we calculate those NNLL terms which are related to the renormalization of m{sub c}, in order to get an estimate of the corresponding uncertainty at the NNLL level. We find that these terms significantly reduce (by typically a factor of two) the error on BR(B {yields} X{sub s}{gamma}) induced by the definition of m{sub c}. Taking into account the experimental accuracy of around 10% and the future prospects of the B factories, we conclude that a NNLL calculation would increase the sensitivity of the observable B {yields} X{sub s}{gamma} to possible new degrees of freedom beyond the SM significantly.

Asatrian, H.M.; /Yerevan Phys. Inst.; Greub, C.; /Bern U.; Hovhannisyan, A.; /Yerevan Phys. Inst.; Hurth, T.; /CERN /SLAC; Poghosyan, V.; /Yerevan Phys. Inst.

2005-06-20T23:59:59.000Z

195

Nucleic Acid Standards - Refinement Parameters  

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

Refinement Parameters Refinement Parameters The DNA/RNA topology and parameter files for X-PLOR are shown below. These were tested with DNA structures and with protein-DNA complexes. X-PLOR topology file X-PLOR parameter files: X-PLOR parameter file For the refinement of high resolution structures (< 1.7 Angstroms) the parameter file with distinct bond distances and bond angles for both C2'-endo and C3'-endo conformations should be considered: X-PLOR parameter file for high resolution structures "New Parameters for the Refinement of Nucleic Acid Containing Structures." Gary Parkinson, Jaroslav Vojtechovsky, Lester Clowney, Axel Brunger*, and Helen M. Berman. (1996) Acta Cryst. D 52, 57-64 Rutgers University, Department of Chemistry, Piscataway, NJ 08855-0939; *The Howard Hughes Medical Institute and Departments of Molecular and

196

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

E-Print Network (OSTI)

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

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

2006-02-20T23:59:59.000Z

197

A study of the appearance of tau neutrinos from a gamma ray burst by detecting their horizontal electromagnetic showers  

E-Print Network (OSTI)

We explore the possibilty of detecting horizontal electromagnetic showers of tau neutrinos from individual gamma ray bursts, in large scale detectors like HiRes and Telescope Array. We study the role of the parameters of a gamma ray burst in determining the expected number of tau events from that burst. The horizontal beam of tau leptons produce visible signals in the atmosphere. We find that there is a slim chance of observing tau lepton appearances from GRBs with Telescope Array. The number of signals is strongly dependent on the Lorentz factor $\\Gamma$, redshift $z$ of a GRB, energy emitted in muon neutrinos and antineutrinos $E_{\

Nayantara Gupta

2003-05-30T23:59:59.000Z

198

Pulsed pyroelectric crystal-powered gamma source  

SciTech Connect

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.

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

199

Subsurface Geotechnical Parameters Report  

SciTech Connect

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.

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

2003-12-17T23:59:59.000Z

200

3-10 keV and 0. 1- to 2-MeV observations of four gamma-ray bursts  

SciTech Connect

Four catalogued ..gamma..-ray bursts that occurred between 79/3/7 and 79/7/31 have been observed over the 3 to 10 keV range by a joint NRL/Los Alamos experiment on the Air Force P78-1 satellite. The bursts were also well observed by members of the interplanetary network. In this paper we present hardness ratios, x-ray/..gamma..-ray luminosity ratios, and time histories. The most significant results presented herein can be summarized as follows: (1) gamma-ray bursters can emit fairly strongly at x-ray energies near the time of the ..gamma.. burst with L/sub x//L/sub ..gamma../ approx. .02 (L/sub x/ approx. 10/sup 37/ ergs s/sup -1/, 3 to 10 keV, assuming a distance of 1 kpc); (2) the centroid of the x-ray emission generally lags the ..gamma..-ray centroid, but there is also evidence for one or more types of x-ray precursor activity; (3) the ..gamma..-ray hardness ratios were not highly variable for these particular events. However, there is some evidence that the ..gamma..-ray spectra softened near the ends of the bursts when the x-ray/..gamma..-ray ratios were high; (4) the x-ray/..gamma..-ray power law number index during times of the strongest ..gamma..-ray emission ranged from 0.8 to approx. 1.1 for the four bursts; (5) the x-ray tail of GB790307 probably can be modeled as the cooling of hot plasma generated during the ..gamma..-ray burst. Simple versions of this model can be used to estimate various source parameters. These estimates imply a distance of a few hundred to a few thousand pc; (6) gamma-ray bursters probably do not produce events similar to classical x-ray bursts independently of the ..gamma..-ray emission.

Laros, J.G.; Evans, W.D.; Fenimore, E.E.; Klebesadel, R.W.; Shulman, S.; Fritz, G.

1983-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "gamma parameter corresponds" from the National Library of EnergyBeta (NLEBeta).
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201

Discovery of \\gamma-ray emission from a strongly lobe-dominated quasar 3C 275.1  

E-Print Network (OSTI)

We systematically analyze the 6-year Fermi/LAT data of the lobe-dominated quasars (LDQs) in the complete LDQ sample from 3CRR survey and report the discovery of high-energy \\gamma-ray emission from 3C 275.1. The \\gamma-ray emission likely associating with 3C 207 is confirmed and significant variability of the lightcurve is identified. We do not find statistically significant \\gamma-ray emission from other LDQs. 3C 275.1 is the known \\gamma-ray quasar with the lowest core dominance parameter (i.e., R=0.11). We also show that both the northern radio hotspot and parsec jet models provide acceptable descriptions to the \\gamma-ray data. Considering the potential \\gamma-ray variability at the timescale of months, the latter is probably more favorable. The number of \\gamma-ray LDQs would increase when the exposure accumulates and hence LDQs could be non-ignorable contributors for the extragalactic \\gamma-ray background.

Liao, Neng-Hui; Li, Shang; Jiang, Wei; Liang, Yun-Feng; Li, Xiang; Zhang, Peng-Fei; Chen, Liang; Bai, Jin-Ming; Fan, Yi-Zhong

2015-01-01T23:59:59.000Z

202

WIPP Compliance Certification Application calculations parameters. Part 1: Parameter development  

SciTech Connect

The Waste Isolation Pilot Plant (WIPP) in southeast New Mexico has been studied as a transuranic waste repository for the past 23 years. During this time, an extensive site characterization, design, construction, and experimental program was completed, which provided in-depth understanding of the dominant processes that are most likely to influence the containment of radionuclides for 10,000 years. Nearly 1,500 parameters were developed using information gathered from this program; the parameters were input to numerical models for WIPP Compliance Certification Application (CCA) Performance Assessment (PA) calculations. The CCA probabilistic codes frequently require input values that define a statistical distribution for each parameter. Developing parameter distributions begins with the assignment of an appropriate distribution type, which is dependent on the type, magnitude, and volume of data or information available. The development of the parameter distribution values may require interpretation or statistical analysis of raw data, combining raw data with literature values, scaling of lab or field data to fit code grid mesh sizes, or other transformation. Parameter development and documentation of the development process were very complicated, especially for those parameters based on empirical data; they required the integration of information from Sandia National Laboratories (SNL) code sponsors, parameter task leaders (PTLs), performance assessment analysts (PAAs), and experimental principal investigators (PIs). This paper, Part 1 of two parts, contains a discussion of the parameter development process, roles and responsibilities, and lessons learned. Part 2 will discuss parameter documentation, traceability and retrievability, and lessons learned from related audits and reviews.

Howarth, S.M.

1997-11-14T23:59:59.000Z

203

New experimental study of low-energy (p,gamma) resonances in magnesium isotopes  

E-Print Network (OSTI)

Proton captures on Mg isotopes play an important role in the Mg-Al cycle active in stellar H shell burning. In particular, the strengths of low-energy resonances with E < 200 keV in 25Mg(p,gamma)26Al determine the production of 26Al and a precise knowledge of these nuclear data is highly desirable. Absolute measurements at such low-energies are often very difficult and hampered by gamma-ray background as well as changing target stoichiometry during the measurements. The latter problem can be partly avoided using higher energy resonances of the same reaction as a normalization reference. Hence the parameters of suitable resonances have to be studied with adequate precision. In the present work we report on new measurements of the resonance strengths omega_gamma of the E = 214, 304, and 326 keV resonances in the reactions 24Mg(p,gamma)25Al, 25Mg(p,gamma)26Al, and 26Mg(p,gamma)27Al, respectively. These studies were performed at the LUNA facility in the Gran Sasso underground laboratory using multiple experimental techniques and provided results with a higher accuracy than previously achieved.

B. Limata; F. Strieder; A. Formicola; G. Imbriani; M. Junker; H. W. Becker; D. Bemmerer; A. Best; R. Bonetti; C. Broggini; A. Caciolli; P. Corvisiero; H. Costantini; A. DiLeva; Z. Elekes; Zs. Fülöp; G. Gervino; A. Guglielmetti; C. Gustavino; Gy. Gyürky; A. Lemut; M. Marta; C. Mazzocchi; R. Menegazzo; P. Prati; V. Roca; C. Rolfs; C. Rossi Alvarez; C. Salvo; E. Somorjai; O. Straniero; F. Terrasi; H. -P. Trautvetter

2010-06-28T23:59:59.000Z

204

World Sheet Commuting beta-gamma CFT and Non-Relativistic StringTheories  

SciTech Connect

We construct a sigma model in two dimensions with Galilean symmetry in flat target space similar to the sigma model of the critical string theory with Lorentz symmetry in 10 flat spacetime dimensions. This is motivated by the works of Gomis and Ooguri[1] and Danielsson et. al.[2, 3]. Our theory is much simpler than their theory and does not assume a compact coordinate. This non-relativistic string theory has a bosonic matter {beta}{gamma} CFT with the conformal weight of {beta} as 1. It is natural to identify time as a linear combination of {gamma} and {bar {gamma}} through an explicit realization of the Galilean boost symmetry. The angle between {gamma} and {bar {gamma}} parametrizes one parameter family of selection sectors. These selection sectors are responsible for having a non-relativistic dispersion relation without a nontrivial topology in the non-relativistic setup, which is one of the major differences from the previous works[1, 2, 3]. This simple theory is the non-relativistic analogue of the critical string theory, and there are many different avenues ahead to be investigated. We mention a possible consistent generalization of this theory with different conformal weights for the {beta}{gamma} CFT. We also mention supersymmetric generalizations of these theories.

Kim, Bom Soo

2007-08-30T23:59:59.000Z

205

Measurements of the CKM Angle phi3/gamma  

SciTech Connect

We present a review on the measurements of the CKM angle {gamma} ({phi}{sub 3}){sup 1} as performed by the BABAR and Belle experiments at the asymmetric-energy e{sup +}e{sup -} B factories colliders PEP-II and KEKB. These measurements are using either charged or neutral B decays. For charged B decays the modes {tilde D}{sup 0}K{sup -}, {tilde D}*{sup 0}K{sup -}, and {tilde D}{sup 0}K*{sup -} are employed, where {tilde D}{sup 0} indicates either a D{sup 0} or a {bar D}{sup 0} meson. Direct CP violation is exploited. It is caused by interferences between V{sub ub} and V{sub cb} accessible transitions that generate asymmetries in the final states. For these decays various methods exist to enhance the sensitivity to the V{sub ub} transition, carrying the weak phase {gamma}. For neutral B decays, the modes D{sup (*){+-}}{pi}{sup {-+}} and D{sup {+-}}{rho}{sup {-+}} are used. In addition to the V{sub ub} and V{sub cb} interferences, these modes are sensitive to the B{sup 0}-{bar B}{sup 0} mixing, so that time dependent analyses are performed to extract sin(2{beta} + {gamma}). An alternative method would use the lower branching ratios decay modes {tilde D}{sup (*)0}{bar K}{sup (*)0} where much larger asymmetries are expected. The various available methods are mostly ''theoretically clean'' and always free of penguins diagrams. In some cases a high sensitivity to {gamma} is expected and large asymmetries may be seen. But these measurements are always experimentally difficult as one has to face with either low branching ratios, or small asymmetries, or additional technical/theoretical difficulties due to Dalitz/SU(3) and re-scattering models needed to treat/estimate nuisance parameters such as unknown strong phases and the relative magnitude of the amplitude of the interfering ''V{sub ub}'' transitions. Thus at the present time only a relatively limited precision on {gamma} can be extracted from these measurements. The current world average is {gamma} = (78{sub -26}{sup +19}){sup o} [1]. For other methods and long term perspectives, as discussed in details, the reader is invited to consult the proceedings of the recent CKM workshop that was held in Nagoya (Japan) in December 2006 [2].

Tisserand, Vincent; /Annecy, LAPP

2007-06-27T23:59:59.000Z

206

Axion — Dilaton Coupling and Gamma — Ray Bursts  

Science Journals Connector (OSTI)

Axions emitted in supernovae are interesting candidates to account for Gamma-Ray Bursts provided their energy can be effectively converted...

O. Bertolami

1999-01-01T23:59:59.000Z

207

Gamma ray burst outflows and afterglows.  

E-Print Network (OSTI)

?? We carry out a theoretical investigation of jet propagation in Gamma Ray Bursts and examine the jitter radiation mechanism as a means of producing… (more)

Morsony, Brian J.

2009-01-01T23:59:59.000Z

208

Gamma Ray Burst Central Engines  

E-Print Network (OSTI)

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

Todd A. Thompson

2008-07-04T23:59:59.000Z

209

Gamma?ray burst spectroscopy  

Science Journals Connector (OSTI)

The statistics and physical properties of gamma ray burst spectral features are presented following a brief review of early theoretical predictions of and experimental searches for such emission. The ?100 observations of 50 keV absorption and 400 keV emission features constitute the largest data base on neutron star lines. Although the statistical significance of individual observations is often weak and interpretation of these features as cyclotron absorption and annihilation radiation poses some theoretical problems it is clear that future observations may have far?reaching implications.

K. Hurley

1988-01-01T23:59:59.000Z

210

Gamma Ray Burst Central Engines  

Science Journals Connector (OSTI)

I review aspects of the theory of long?duration gamma?ray burst (GRB) central engines. I focus on 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 ?1 for a timescale of ?10–100? s is emphasized.

Todd A. Thompson

2008-01-01T23:59:59.000Z

211

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

E-Print Network (OSTI)

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.

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

2014-03-28T23:59:59.000Z

212

Neutron/gamma dose separation by the multiple-ion-chamber technique  

SciTech Connect

Many mixed n/..gamma.. dosimetry systems rely on two dosimeters, one composed of a tissue-equivalent material and the other made from a non-hydrogenous material. The paired chamber technique works well in fields of neutron radiation nearly identical in spectral composition to that in which the dosimeters were calibrated. However, this technique is drastically compromised in phantom due to the degradation of the neutron spectrum. The three-dosimeter technique allows for the fall-off in neutron sensitivity of the two non-hydrogenous dosimeters. Precise and physically meaningful results were obtained with this technique with a D-T source in air and in phantom and with simultaneous D-T neutron and /sup 60/Co gamma ray irradiation in air. The MORSE-CG coupled n/..gamma.. three-dimensional Monte Carlo code was employed to calculate neutron and gamma doses in a water phantom. Gamma doses calculated in phantom with this code were generally lower than corresponding ion chamber measurements. This can be explained by the departure of irradiation conditions from ideal narrow-beam geometry. 97 references.

Goetsch, S.J.

1983-01-01T23:59:59.000Z

213

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

E-Print Network (OSTI)

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

California at Santa Cruz, University of

214

An Exactly Separable {gamma}-Rigid Version of The X(5) Critical Point Symmetry  

SciTech Connect

A {gamma}-rigid version (with {gamma}=0) of the X(5) critical point symmetry is constructed. The model, to be called X(3) since it is proved to cointain three degrees of freedom, utilizes an infinite well potential, is based on exact separation of variables, and leads to parameter free (up to overall scale factors) predictions for spectra and B(E2) transition rates, which are in good agreement with existing experimental data for Os and Pt. An unexpected similarity of the {beta}1 bands of the X(5) nuclei 150Nd, 152Sm, 154Gd, and 156Dy to the X(3) predictions is observed.

Bonatsos, D.; Lenis, D.; Petrellis, D. [Institute of Nuclear Physics, National Center for Scientific Research 'Demokritos', GR-15310 Aghia Paraskevi, Attiki (Greece); Terziev, P. A. [Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, 72 Tzarigrad Road, BG-1784 Sofia (Bulgaria); Yigitoglu, I. [Hasan Ali Yucel Faculty of Education, Istanbul University, TR-34470 Beyazit, Istanbul (Turkey)

2007-04-23T23:59:59.000Z

215

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

E-Print Network (OSTI)

A coherent x-ray or gamma ray can be created from a dense electron beam propagating through an intense laser undulator. It is analyzed by using the Landau damping theory which suits better than the conventional linear analysis for the free electron laser, as the electron beam energy spread is high. The analysis suggests that the currently available physical parameters would enable the generation of the coherent gamma ray of up to 100 keV. The electron quantum diffraction suppresses the FEL action, by which the maximum radiation energy to be generated is limited.

S. Son; S. J. Moon

2012-02-12T23:59:59.000Z

216

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

SciTech Connect

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.

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

217

Observations of Gamma-Ray Bursts at Extreme Energies  

E-Print Network (OSTI)

of Gamma-Ray Bursts . . . . . . . . . . . . . Redshift-CRUZ OBSERVATIONS OF GAMMA-RAY BURSTS AT EXTREME ENERGIES AAncient Unvierse with Gamma-Ray Bursts, pages 330–333. AIP,

Aune, Taylor

2012-01-01T23:59:59.000Z

218

Recoilless Nuclear Resonance Absorption of Gamma Radiation  

Science Journals Connector (OSTI)

...GAMMA-RAYS, ARKIV FOR FYSIK 6 : 49 ( 1953...OF GAMMA-RAYS - THEORY AND PRELIMINARY EXPERIMENTS...energy loss. The basic feature of this method...prediction of the theory was that the recoilless...formulation of the theory that the mo-mentum...Malmfors, Arkiv Fysik 6, 49 (1953...

Rudolf L. Mössbauer

1962-09-07T23:59:59.000Z

219

The GAMMA-400 gamma-ray telescope characteristics. Angular resolution and electrons/protons separation  

E-Print Network (OSTI)

The measurements of gamma-ray fluxes and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV, which will be implemented by the specially designed GAMMA-400 gamma-ray telescope, concern with the following broad range of science topics. Searching for signatures of dark matter, surveying the celestial sphere in order to study gamma-ray point and extended sources, measuring the energy spectra of Galactic and extragalactic diffuse gamma-ray emission, studying gamma-ray bursts and gamma-ray emission from the Sun, as well as high precision measuring spectra of high-energy electrons and positrons, protons and nuclei up to the knee. To clarify these scientific problems with the new experimental data the GAMMA-400 gamma-ray telescope possesses unique physical characteristics comparing with previous and present experiments. For gamma-ray energies more than 100 GeV GAMMA-400 provides the energy resolution of ~1% and angular resolution better than 0.02 deg. The methods developed to reconstru...

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; Boyarchuk, K A; 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

2014-01-01T23:59:59.000Z

220

BBGKY kinetic approach for an e{sup -}e{sup +}{gamma} plasma created from the vacuum in a strong laser-generated electric field: The one-photon annihilation channel  

SciTech Connect

In the present work a closed system of kinetic equations is obtained from the truncation of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for the description of the vacuum creation of an electron-positron plasma and secondary photons due to a strong laser field. This truncation is performed in the Markovian approximation for the one-photon annihilation channel which is accessible due to the presence of the strong external field. Estimates of the photon production rate are obtained for different domains of laser field parameters (frequency {nu} and field strength E). A huge quantity of optical photons of the quasiclassical laser field is necessary to satisfy the conservation laws of the energy and momentum of the constituents (e{sup -}, e{sup +} and {gamma}) in this channel. Since the number of these optical photons corresponds to the order of perturbation theory, a vanishingly small photon production rate results for the optical region and strongly subcritical fields E<gamma}-ray region {nu} < or approx. m the required number of laser photons is small and the production rate of photons from the one-photon annihilation process becomes accessible to observations for subcritical fields E < or approx. E{sub c}. In the infrared region the photon distribution has a 1/k spectrum typical for flicker noise.

Blaschke, D. B. [Institute for Theoretical Physics, University of Wroclaw, 50-204 Wroclaw (Poland); Bogoliubov Laboratory for Theoretical Physics, Joint Institute for Nuclear Research, RU - 141980 Dubna (Russian Federation); Dmitriev, V. V.; Smolyansky, S. A. [Department of Physics, Saratov State University, RU - 410026 Saratov (Russian Federation); Roepke, G. [Institut fuer Physik, University of Rostock, D - 18051 Rostock (Germany)

2011-10-15T23:59:59.000Z

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


221

Search for the Decay J/psi -> gamma + invisible  

E-Print Network (OSTI)

A search for J/psi radiative decay to weakly interacting neutral final states was performed using the CLEO-c detector at CESR. A total of 3.7 x 10^{6} tagged J/psi events was collected at the psi(2S) resonance and used to study the decay J/psi -> gamma+X, where X is a narrow state that is invisible to the detector. No significant signal was observed and upper limits on the branching fraction were set for masses m_X up to 960 MeV/c^2. The upper limit corresponding to m_X=0 is 4.3x 10^{-6} at the 90% confidence level.

The CLEO Collaboration; J. Insler

2010-03-01T23:59:59.000Z

222

Brief paper: A parameter space approach to constrained variance PID controller design  

Science Journals Connector (OSTI)

This paper presents a parameter space approach to constrained variance and minimum variance PID controller design for LTI models. The technique is based on rational transfer functions of the plant and noise models. Loci corresponding to a fixed variance ... Keywords: Low-order controllers, Minimum variance, Multi-objective, PID, Parameter space

P. B. Dickinson; A. T. Shenton

2009-03-01T23:59:59.000Z

223

Accessing the population of high redshift Gamma Ray Bursts  

E-Print Network (OSTI)

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...

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

224

A novel paradigm for short gamma-ray bursts  

E-Print Network (OSTI)

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 number 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 sh...

Rezzolla, Luciano

2014-01-01T23:59:59.000Z

225

A novel paradigm for short gamma-ray bursts  

E-Print Network (OSTI)

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 number 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.

Luciano Rezzolla; Pawan Kumar

2014-10-30T23:59:59.000Z

226

New Limits On Gamma-Ray Emission From Galaxy Clusters  

E-Print Network (OSTI)

Galaxy clusters are predicted to produce gamma-rays through cosmic ray interactions and/or dark matter annihilation, potentially detectable by the Fermi Large Area Telescope (Fermi-LAT). We present a new, independent stacking analysis of Fermi-LAT photon count maps using the 79 richest nearby clusters (zSurvey (2MASS) cluster catalog. We obtain the lowest limit on the photon flux to date, 1.1e-11 ph/s/cm^2 (95% confidence) per cluster in the 0.8--100~GeV band, which corresponds to a luminosity limit of 1.7e44 ph/s. We also constrain the emission limits in a range of narrower energy bands. Scaling to recent cosmic ray acceleration and gamma-ray emission models, we find that cosmic rays represent a negligible contribution to the intra-cluster energy density and gas pressure. Furthermore, either accretion shocks must have lower Mach numbers than usually assumed (2--4) or significantly less than 50% of the baryon mass has been processed through such shocks, and thus, the majo...

Griffin, Rhiannon D; Kochanek, Christopher S

2014-01-01T23:59:59.000Z

227

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

E-Print Network (OSTI)

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 ...

Ham, Wendy D. (Wendy Decker)

2005-01-01T23:59:59.000Z

228

Neutron And Gamma Detector Using An Ionization Chamber With An...  

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

Neutron And Gamma Detector Using An Ionization Chamber Neutron And Gamma Detector Using An Ionization Chamber With An Integrated Body And Moderator A detector for detecting...

229

Gamma-insensitive optical sensor  

DOE Patents (OSTI)

An ultra-violet/visible/infra-red gamma-insensitive gas avalanche focal plane array 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.

Kruger, Hans W. (Walnut Creek, CA)

1994-01-01T23:59:59.000Z

230

Gamma-insensitive optical sensor  

DOE Patents (OSTI)

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.

Kruger, H.W.

1994-03-15T23:59:59.000Z

231

Correspondence Researchistheseed  

E-Print Network (OSTI)

. This is why the Irish government treats public spending on R&D as capital expenditure, as it does for roads? Most of the wealth in all countries is in the intellectual capital of individuals, firms and institutions. In developed countries, including Ireland, intellectual capital generally exceeds 80% of total

Reynolds, John D.

232

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

E-Print Network (OSTI)

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|

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

233

Conservative constraints on dark matter annihilation into gamma rays  

SciTech Connect

Using gamma-ray data from observations of the Milky Way, Andromeda (M31), and the cosmic background, we calculate conservative upper limits on the dark matter self-annihilation cross section to monoenergetic gamma rays, <{sigma}{sub A}v>{sub {gamma}}{sub {gamma}}, over a wide range of dark matter masses. (In fact, over most of this range, our results are unchanged if one considers just the branching ratio to gamma rays with energies within a factor of a few of the endpoint at the dark matter mass.) If the final-state branching ratio to gamma rays, Br({gamma}{gamma}), were known, then <{sigma}{sub A}v>{sub {gamma}}{sub {gamma}}/Br({gamma}{gamma}) would define an upper limit on the total cross section; we conservatively assume Br({gamma}{gamma}) > or approx. 10{sup -4}. An upper limit on the total cross section can also be derived by considering the appearance rates of any standard model particles; in practice, this limit is defined by neutrinos, which are the least detectable. For intermediate dark matter masses, gamma-ray-based and neutrino-based upper limits on the total cross section are comparable, while the gamma-ray limit is stronger for small masses and the neutrino limit is stronger for large masses. We comment on how these results depend on the assumptions about astrophysical inputs and annihilation final states, and how GLAST and other gamma-ray experiments can improve upon them.

Mack, Gregory D.; Yueksel, Hasan [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, Ohio 43210 (United States); Jacques, Thomas D.; Bell, Nicole F. [School of Physics, The University of Melbourne, Victoria 3010 (Australia); Beacom, John F. [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, Ohio 43210 (United States); Department of Astronomy, Ohio State University, Columbus, Ohio 43210 (United States)

2008-09-15T23:59:59.000Z

234

Gamma-Ray Bursts and Particle Astrophysics  

E-Print Network (OSTI)

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.

B. Gendre

2008-07-24T23:59:59.000Z

235

Gamma-Ray Burst Early Afterglows  

E-Print Network (OSTI)

The successful launch and operation of NASA's Swift Gamma-Ray Burst Explorer open a new era for the multi-wavelength study of the very early afterglow phase of gamma-ray bursts (GRBs). GRB early afterglow information is essential to explore the unknown physical composition of GRB jets, the link between the prompt gamma-ray emission and the afterglow emission, the GRB central engine activity, as well as the immediate GRB environment. Here I review some of the recent theoretical efforts to address these problems and describe how the latest Swift data give answers to these outstanding questions.

Bing Zhang

2005-09-19T23:59:59.000Z

236

Design of dual column water purification system for industrial gamma irradiator based of PUROLITE® resins  

Science Journals Connector (OSTI)

Abstract When gamma irradiators are not in use, they have to be stored in nuclear grade water pool. This water serves as shielding and the medium for the removal of generated heat. To prevent corrosion damage to the gamma source and other equipment a purification system controls the water quality. Also, this system serves as the make-up water system for supplies and maintains the de-ionized water level in the gamma source storage pool. In this paper, the design of the dual system for purification and make-up water for optimal water supply and its chemical parameters in the gamma source storage pool is presented. For this purpose, the characteristics of activated carbon purifier, anionic and cationic demineralizers have been determined. “Aerb Safety Standard”, “Purolite Ion Exchange Design Code” and “Canadian Water Refining Company Manual” have been used to design IR-136 gamma irradiator storage pool purification and make-up water system. The main objective of the design is to maintain water purity throughout the storage time.

Reza Gholizadeh Aghoyeh; Hossein Khalafi

2014-01-01T23:59:59.000Z

237

High-spin structure and multiphonon {gamma} vibrations in very neutron-rich {sup 114}Ru  

SciTech Connect

High-spin levels of the neutron-rich {sup 114}Ru have been investigated by measuring the prompt {gamma} rays in the spontaneous fission of {sup 252}Cf. The ground-state band and one-phonon {gamma}-vibrational band have been extended up to 14{sup +} and 9{sup +}, respectively. Two levels are proposed as the members of a two-phonon {gamma}-vibrational band. A back bending (band crossing) has been observed in the ground-state band at ({h_bar}/2{pi}){omega}{approx_equal} 0.40 MeV. Using the triaxial deformation parameters, the cranked shell model calculations indicate that this back bending in {sup 114}Ru should originate from the alignment of a pair of h{sub 11/2} neutrons. Triaxial projected shell model calculations for the {gamma}-vibrational band structures of {sup 114}Ru are in good agreement with the experimental data. However, when using the oblate deformation parameters, both of the above-calculated results are not in agreement with the experimental data.

Yeoh, E. Y.; Wang, J. G.; Ding, H. B.; Gu, L.; Xu, Q.; Xiao, Z. G. [Department of Physics, Tsinghua University, Beijing 100084 (China); Zhu, S. J. [Department of Physics, Tsinghua University, Beijing 100084 (China); Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Hamilton, J. H.; Li, K.; Ramayya, A. V.; Hwang, J. K. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Liu, Y. X. [School of Science, Huzhou Teachers College, Huzhou 313000 (China); Liu, S. H. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); UNIRIB/Oak Ridge Associated Universities, Oak Ridge, Tennessee 37831 (United States); Sun, Y. [Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Sheikh, J. A.; Bhat, G. H. [Department of Physics, University of Kashmir, Srinagar 190 006 (India); Luo, Y. X. [Department of Physics, Vanderbilt University, Nashville, Tennessee 37235 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Rasmussen, J. O.; Lee, I. Y. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Ma, W. C. [Department of Physics, Mississippi State University, Mississippi State, Mississippi 39762 (United States)

2011-05-15T23:59:59.000Z

238

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

SciTech Connect

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.

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

239

Correspondence analysis applied to a comparison of some rhyolitic zones in the Noranda area (Quebec, Canada)  

Science Journals Connector (OSTI)

Correspondence analysis was applied to 177 chemical analyses (major elements) of rocks from some rhyolitic zones of the Noranda area (Quebec). The objective was to grade the...

Christina Dumitriu; Roger Webber…

1979-06-01T23:59:59.000Z

240

Gravitational waves and gamma-ray bursts  

E-Print Network (OSTI)

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

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

2012-05-11T23:59:59.000Z

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


241

Studying Gamma Ray Bursts from a  

E-Print Network (OSTI)

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

Â?umer, Slobodan

242

Gravitational waves and short gamma ray bursts.  

E-Print Network (OSTI)

??Short hard gamma-ray bursts (GRB) are believed to be produced by compact binary coalescences (CBC) { either double neutron stars or neutron star{black hole binaries.… (more)

Predoi, Valeriu

2012-01-01T23:59:59.000Z

243

Gamma-Ray Pulsar Studies With GLAST  

SciTech Connect

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.

Thompson, D.J.; /NASA, Goddard

2011-11-23T23:59:59.000Z

244

Flares in Gamma Ray Bursts  

Science Journals Connector (OSTI)

The flare activity that is observed in GRBs soon after the prompt emission with the XRT (0.3–10 KeV) instrument on Board of the Swift satellite is leading to important clues in relation to the physical characteristics of the mechanism generating the emission of energy in Gamma Ray Bursts. We will briefly refer to the results obtained with the recent analysis [1] and [2] and discuss the preliminary results we obtained with a new larger sample of GRBs [limited to early flares] based on fitting of the flares using the Norris 2005 profile. We find in agreement with previous results that XRT flares follow the main characteristics observed in [3] for the prompt emission spikes. The estimate of the flare energy for the subsample with redshift is rather robust and an attempt is made using the redshisft sample to estimate how the energy emitted in flares depends on time. We used a H 0 ?=?70?km/s/Mpc ? ? ?=?0.7 ? m ?=?0.3 cosmology.

G. Chincarini; J. Mao; F. Pasotti; R. Margutti; C. Guidorzi; M. G. Bernardini; Swfit Italian team

2008-01-01T23:59:59.000Z

245

The gamma?ray burst capabilities of BATSE and the Gamma Ray Observatory  

Science Journals Connector (OSTI)

The Gamma Ray Observatory (GRO) scheduled for launch in 1990 will provide new and enhanced capabilities for the study of gamma?ray bursts. These include higher sensitivity increased time resolution broader energy coverage rapid burst data dissemination and burst location by a single spacecraft. All four of the GRO instruments have burst capabilities however the Burst and Transient Source Experiment (BATSE) is designed primarily for the study of gamma?ray bursts. The capabilities of BATSE and the GRO for gamma?ray burst studies are described.

G. J. Fishman

1988-01-01T23:59:59.000Z

246

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

E-Print Network (OSTI)

: pb = C + Va(pa) Equation 3 where C is a constant. Ash content can therefore be geophysically determined as variations In log-derived bulk density measurements are in direct response to variations in ash content. However, when any of the above... by applying the relationships between geophysi cally-derived gamma-gamma density and laboratory-derived percent dry ash. The linear gamma-gamma density/percent dry ash relationship is dependent upon a constant fuel ratio (percent fixed carbon...

Wright, David Scott

1984-01-01T23:59:59.000Z

247

Gamma Ray Bursts from Ordinary Cosmic Strings  

E-Print Network (OSTI)

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.

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

1993-02-12T23:59:59.000Z

248

Neutrinos and Gamma Rays from Galaxy Clusters  

E-Print Network (OSTI)

The next generation of neutrino and gamma-ray detectors should provide new insights into the creation and propagation of high-energy protons within galaxy clusters, probing both the particle physics of cosmic rays interacting with the background medium and the mechanisms for high-energy particle production within the cluster. In this paper we examine the possible detection of gamma-rays (via the GLAST satellite) and neutrinos (via the ICECUBE and Auger experiments) from the Coma cluster of galaxies, as well as for the gamma-ray bright clusters Abell 85, 1758, and 1914. These three were selected from their possible association with unidentified EGRET sources, so it is not yet entirely certain that their gamma-rays are indeed produced diffusively within the intracluster medium, as opposed to AGNs. It is not obvious why these inconspicuous Abell-clusters should be the first to be seen in gamma-rays, but a possible reason is that all of them show direct evidence of recent or ongoing mergers. Their identification with the EGRET gamma-ray sources is also supported by the close correlation between their radio and (purported) gamma-ray fluxes. Under favorable conditions (including a proton spectral index of 2.5 in the case of Abell 85, and sim 2.3 for Coma, and Abell 1758 and 1914), we expect ICECUBE to make as many as 0.3 neutrino detections per year from the Coma cluster of galaxies, and as many as a few per year from the Abell clusters 85, 1758, and 1914. Also, Auger may detect as many as 2 events per decade at ~ EeV energies from these gamma-ray bright clusters.

Brandon Wolfe; Fulvio Melia; Roland M. Crocker; Raymond R. Volkas

2008-07-04T23:59:59.000Z

249

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

E-Print Network (OSTI)

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

Enomoto, Ryoji

250

MAGNETIZATION DEGREE OF GAMMA-RAY BURST FIREBALLS: NUMERICAL STUDY  

SciTech Connect

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.

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

251

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

252

Iterative Dense Correspondence Correction Through Bundle Adjustment Feedback-Based Error Detection  

SciTech Connect

A novel method to detect and correct inaccuracies in a set of unconstrained dense correspondences between two images is presented. Starting with a robust, general-purpose dense correspondence algorithm, an initial pose estimate and dense 3D scene reconstruction are obtained and bundle-adjusted. Reprojection errors are then computed for each correspondence pair, which is used as a metric to distinguish high and low-error correspondences. An affine neighborhood-based coarse-to-fine iterative search algorithm is then applied only on the high-error correspondences to correct their positions. Such an error detection and correction mechanism is novel for unconstrained dense correspondences, for example not obtained through epipolar geometry-based guided matching. Results indicate that correspondences in regions with issues such as occlusions, repetitive patterns and moving objects can be identified and corrected, such that a more accurate set of dense correspondences results from the feedback-based process, as proven by more accurate pose and structure estimates.

Hess-Flores, M A; Duchaineau, M A; Goldman, M J; Joy, K I

2009-11-23T23:59:59.000Z

253

Editorial. An Italian correspondence, an Italian earthquake and the homes of The Royal Society  

Science Journals Connector (OSTI)

...correspondence, an Italian earthquake and the homes of The Royal Society Terry Quinn Bureau...of Sir Thomas Gresham and the original home of The Royal Society from 1660-1710...CORRESPONDENCE, AN ITALIAN EARTHQUAKE AND THE HOMES OF THE ROYAL SOCIETY By the time he was...

2005-01-01T23:59:59.000Z

254

*Corresponding author. E-mail address: #ame@zen.phys.columbia.edu (J. Hong).  

E-Print Network (OSTI)

and Methods in Physics Research A 452 (2000) 192}204 Laboratory tests on neutron shields for gamma in the past. We report here on the "rst prototype models for supershields based on boron and hydrogen. We the secondary particle production. Neutron-induced background can be the dominant component of the total back

255

Development of Particle Induced Gamma-Ray Emission Methods for Nondestructive Determination of Isotopic Composition of Boron and Its Total Concentration in Natural and Enriched Samples  

Science Journals Connector (OSTI)

Development of Particle Induced Gamma-Ray Emission Methods for Nondestructive Determination of Isotopic Composition of Boron and Its Total Concentration in Natural and Enriched Samples ... The isotopic composition of boron in natural and enriched samples was determined by comparing peak area ratios corresponding to 10B and 11B of samples to natural boric acid standard. ...

Sumit Chhillar; Raghunath Acharya; Suparna Sodaye; Pradeep K. Pujari

2014-10-14T23:59:59.000Z

256

Finding (or not) New Gamma-ray Pulsars with GLAST  

E-Print Network (OSTI)

Young energetic pulsars will likely be the largest class of Galactic sources observed by GLAST, with many hundreds detected. Many will be unknown as radio pulsars, making pulsation detection dependent on radio and/or x-ray observations or on blind periodicity searches of the gamma-rays. Estimates for the number of pulsars GLAST will detect in blind searches have ranged from tens to many hundreds. I argue that the number will be near the low end of this range, partly due to observations being made in a scanning as opposed to a pointing mode. This paper briefly reviews how blind pulsar searches will be conducted using GLAST, what limits these searches, and how the computations and statistics scale with various parameters.

Scott M. Ransom

2007-04-09T23:59:59.000Z

257

Dark matter and pulsar model constraints from Galactic Center Fermi-LAT gamma-ray observations  

Science Journals Connector (OSTI)

Employing Fermi-LAT gamma-ray observations, several independent groups have found excess extended gamma-ray emission at the Galactic Center (GC). Both annihilating dark matter (DM) or a population of ?103 unresolved millisecond pulsars (MSPs) are regarded as well-motivated possible explanations. However, there are significant uncertainties in the diffuse galactic background at the GC. We have performed a revaluation of these two models for the extended gamma-ray source at the GC by accounting for the systematic uncertainties of the Galactic diffuse emission model. We also marginalize over point-source and diffuse background parameters in the region of interest. We show that the excess emission is significantly more extended than a point source. We find that the DM (or pulsar-population) signal is larger than the systematic errors and therefore proceed to determine the sectors of parameter space that provide an acceptable fit to the data. We find that a population of 1000–2000 MSPs with parameters consistent with the average spectral shape of Fermi-LAT measured MSPs is able to fit the GC excess emission. For DM, we find that a pure ?+?- annihilation channel is not a good fit to the data. But a mixture of ?+?- and bb¯ with a ??v? of order the thermal relic value and a DM mass of around 20 to 60 GeV provides an adequate fit.

Chris Gordon and Oscar Macías

2013-10-21T23:59:59.000Z

258

On Gamma-Ray Bursts  

E-Print Network (OSTI)

(Shortened) We show by example how the uncoding of Gamma-Ray Bursts (GRBs) offers unprecedented possibilities to foster new knowledge in fundamental physics and in astrophysics. After recalling some of the classic work on vacuum polarization in uniform electric fields by Klein, Sauter, Heisenberg, Euler and Schwinger, we summarize some of the efforts to observe these effects in heavy ions and high energy ion collisions. We then turn to the theory of vacuum polarization around a Kerr-Newman black hole, leading to the extraction of the blackholic energy, to the concept of dyadosphere and dyadotorus, and to the creation of an electron-positron-photon plasma. We then present a new theoretical approach encompassing the physics of neutron stars and heavy nuclei. It is shown that configurations of nuclear matter in bulk with global charge neutrality can exist on macroscopic scales and with electric fields close to the critical value near their surfaces. These configurations may represent an initial condition for the process of gravitational collapse, leading to the creation of an electron-positron-photon plasma: the basic self-accelerating system explaining both the energetics and the high energy Lorentz factor observed in GRBs. We then turn to recall the two basic interpretational paradigms of our GRB model. [...] We then turn to the special role of the baryon loading in discriminating between "genuine" short and long or "fake" short GRBs [...] We finally turn to the GRB-Supernova Time Sequence (GSTS) paradigm: the concept of induced gravitational collapse. [...] We then present some general conclusions.

Remo Ruffini; Maria Grazia Bernardini; Carlo Luciano Bianco; Letizia Caito; Pascal Chardonnet; Christian Cherubini; Maria Giovanna Dainotti; Federico Fraschetti; Andrea Geralico; Roberto Guida; Barbara Patricelli; Michael Rotondo; Jorge Armando Rueda Hernandez; Gregory Vereshchagin; She-Sheng Xue

2008-04-17T23:59:59.000Z

259

Propagation of Neutrinos through Magnetized Gamma-Ray Burst Fireball  

E-Print Network (OSTI)

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.

Sarira Sahu; Nissim Fraija; Yong-Yeon Keum

2009-11-10T23:59:59.000Z

260

The Excitation of Solar Oscillations \\Gamma\\GammaObservations and Simulations  

E-Print Network (OSTI)

The Excitation of Solar Oscillations \\Gamma\\GammaObservations and Simulations Philip R. Goode Big Bear Solar Observatory, New Jersey Institute of Technology, Big Bear City, CA 92314 Louis H. Strous Big Bear Solar Observatory, New Jersey Institute of Technology, Big Bear City, CA 92314 Lockheed

Stein, Robert

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


261

Very high-energy gamma rays from gamma-ray bursts  

Science Journals Connector (OSTI)

...which means that the energy thresholds of such...detecting gamma rays with energies as low as 30GeV...there have been two solar arrays in operation: STACEE in New Mexico (Hanna et al. 2002...not based around a solar array, employs rather...airshower arrays If the energy of the incoming gamma...

2007-01-01T23:59:59.000Z

262

Dual Gamma Neutron Directional Elpasolite Detector  

SciTech Connect

Some applications, particularly in homeland security, require detection of both neutron and gamma radiation. Typically, this is accomplished with a combination of two detectors registering neutrons and gammas separately. We have investigated a new type of neutron/gamma (n/?) directional detection capability. We explored a new class of scintillator, cerium (Ce)-doped Elpasolites such as Cs2LiYCl6:Ce (CLYC), Cs2LiLaCl6 (CLLC), Cs2LiLaBr6:Ce (CLLB), or Cs2LiYBr6:Ce (CLYB). These materials are capable of providing energy resolution as good as 2.9% at 662 keV (FWHM), which is better than that of NaI:Tl. Because they contain 6Li, Elpasolites can also detect thermal neutrons. In the energy spectra, the full energy thermal neutron peak appears near or above 3 GEEn MeV. Thus, very effective pulse height discrimination is possible. In addition, the core-to-valence luminescence (CVL) provides Elpasolites with different temporal responses under gamma and neutron excitation, and, therefore, may be exploited for effective pulse shape discrimination. For instance, the CLLC emission consists of two main components: (1) CVL spanning from 220 nm to 320 nm and (2) Ce emission found in the range of 350 to 500 nm. The former emission is of particular interest because it appears only under gamma excitation. It is also very fast, decaying with a 2 ns time constant. The n/? discrimination capability of Elpasolite detectors may be optimized by tuning the cerium doping content for maximum effect on n/? pulse shape differences. The resulting Elpasolite detectors have the ability to collect neutron and gamma data simultaneously, with excellent discrimination. Further, an array of four of these Elpasolites detectors will perform directional detection in both the neutron and gamma channels simultaneously.

Guss, P. P.; Mukhopadhyay, S.

2013-09-01T23:59:59.000Z

263

Gamma-Ray Studies in Boron-10  

Science Journals Connector (OSTI)

Gamma rays emanating from the 7.56-Mev level of B10 were analyzed with a five-crystal pair spectrometer. Cascade gamma rays were investigated by recording the spectra in coincidence with the 2.40, 0.72, 2.15, and 5.41-Mev gamma-ray transitions. The branching ratios for the decay of the 7.56-Mev level were found to be 76%, 9%, and 15% for 6.84, 5.41, and 2.40-Mev gamma rays, respectively. For the 2.15-Mev level, the respective branching ratios for 2.15, 1.43, and 0.41-Mev gamma rays were shown to be 16%, 29%, and 55%. The partial width for the 3.01-Mev transition was found to be less than 1% of the total width of the 5.16-Mev state in B10. Combining this result with the data of Meyer-Schützmeister and Hanna, the gamma-ray width of the 5.16-Mev level was found to be 0.51 ev and the alpha width 32gamma-ray widths may be resolved if the 5.16-Mev state in B10 is assumed to be a doublet.

Esther L. Sprenkel and James W. Daughtry

1961-11-01T23:59:59.000Z

264

Theoretical study of ionization profiles of molecular clouds near supernova remnants: Tracing the hadronic origin of GeV gamma radiation  

E-Print Network (OSTI)

Context: Since a few years, signatures of supernova remnants associated with molecular clouds have been detected in gamma rays. Whether these gamma rays are generated by cosmic ray electrons or by cosmic ray protons is usually not known. The detection of hadronic ionization signatures in spatial coincidence with gamma ray signatures can help to unambiguously identify supernova remnants as sources of cosmic ray protons. Methods: In order to calculate hadronic signatures from cosmic ray-induced ionization for an examination of the origin of the observed gamma rays, the transport equation for cosmic ray protons propagating in a molecular cloud, including the relevant momentum loss processes, is solved analytically and the proton flux at any position in the cloud is determined. Results: Since the solution of the transport equation is obtained for arbitrary source functions, it can be used for a variety of supernova remnants. The corresponding theoretical ionization rate, as a function of the penetration depth, is...

Schuppan, Florian; Tjus, Julia Becker

2014-01-01T23:59:59.000Z

265

Gamma-ray bursts from accreting black holes in neutron star mergers  

E-Print Network (OSTI)

By means of three-dimensional hydrodynamic simulations with a Eulerian PPM code we investigate the formation and the properties of the accretion torus around the stellar mass black hole which originates from the merging of two neutron stars. The simulations are performed with four nested cartesian grids which allow for both a good resolution near the central black hole and a large computational volume. They include the use of a physical equation of state as well as the neutrino emission from the hot matter of the torus. The gravity of the black hole is described with a Newtonian and alternatively with a Paczynski-Wiita potential. In a post-processing step, we evaluate our models for the energy deposition by nu-nubar annihilation around the accretion torus. Our models show that nu-nubar annihilation can yield the energy to account for weak, short gamma-ray bursts, if moderate beaming is involved. In fact, the barrier of the dense baryonic gas of the torus suggests that the low-density pair-photon-plasma is beamed as axial jets into a fraction 2 delta Omega/ (4 pi) between 1/100 and 1/10 of the sky, corresponding to opening half-angles of roughly ten to several tens of degrees. Thus gamma-burst energies of 10^{50}--10^{51} erg seem within the reach of our models (if the source is interpreted as radiating isotropically), corresponding to luminosities around 10^{51} erg/s for typical burst durations of 0.1--1 s. Gravitational capture of radiation by the black hole, redshift and ray bending do not reduce the jet energy significantly. Effects associated with the Kerr character of the rapidly rotating black hole, however, could increase the gamma-burst energy considerably, and effects due to magnetic fields might even be required to get the energies for long complex gamma-ray bursts.

M. Ruffert; H. -Th. Janka

1998-09-23T23:59:59.000Z

266

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)

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 ...

Kosinski-Collins, Melissa Sue, 1978-

2005-01-01T23:59:59.000Z

267

Fixed Parameter Algorithms Daniel Marx  

E-Print Network (OSTI)

, for example k-CLIQUE and k-INDEPENDENT SET, no FPT algorithm is known. Can we show that these problems if and only if it has a vertex cover of size n - k. Transforming an INDEPENDENT SET instance (G, k, but INDEPENDENT SET is not known to be FPT. Fixed Parameter Algorithms ­ p.5/41 #12;Parameterized reduction

Fondements et Applications, Université Paris 7

268

Fixed Parameter Algorithms Dniel Marx  

E-Print Network (OSTI)

complexity Problem: VERTEX COVER INDEPENDENT SET Input: Graph G, integer k Graph G, integer k Question-complete NP-complete Fixed Parameter Algorithms ­ p.3/40 #12;Parameterized complexity Problem: VERTEX COVER INDEPENDENT SET Input: Graph G, integer k Graph G, integer k Question: Is it possible to cover the edges

Narasayya, Vivek

269

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

E-Print Network (OSTI)

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.

Constantinos Kalapotharakos; Alice K. Harding; Demosthenes Kazanas

2014-07-27T23:59:59.000Z

270

High spins in gamma-soft nuclei  

SciTech Connect

Nuclei which are soft with respect to the ..gamma.. shape degree of freedom are expected to have many different structures coexisting in the near-yrast regime. In particular, the lowest rotational quasi-particle in a high-j shell exerts a strong polarizing effect on ..gamma... The ..gamma.. to which it drives is found to vary smoothly over a 180/sup 0/ range as the position of the Fermi level varies. This simple rule is seen to have a direct connection with the energy staggering of alternate spin states in rotational bands. A diagram is presented which provides a general theoretical reference for experimental tests of the relation between ..gamma.., spin staggering, configuration, and nucleon number. In a quasicontinuum spectrum, the coexistence of different structures are expected to make several unrelated features appear within any one slice of sum energy and multiplicity. However, it is also seen that the in-band moment of inertia may be similar for many bands of different ..gamma...

Leander, G.A.; Frauendorf, S.; May, F.R.

1982-01-01T23:59:59.000Z

271

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

E-Print Network (OSTI)

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

Bandstra, Mark ShenYu

2010-01-01T23:59:59.000Z

272

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

E-Print Network (OSTI)

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

Doran, Simon J.

273

Correspondence among the Correlation, RMSE, and Heidke Forecast Verification Measures; Refinement of the Heidke Score  

Science Journals Connector (OSTI)

The correspondence among the following three forecast verification scores, based on forecasts and their associated observations, is described: 1) the correlation score, 2) the root-mean-square error (RMSE) score, and 3) the Heidke score (based on ...

Anthony G. Barnston

1992-12-01T23:59:59.000Z

274

doi: 10.3319/TAO.2011.09.23.02(T) * Corresponding author  

E-Print Network (OSTI)

doi: 10.3319/TAO.2011.09.23.02(T) * Corresponding author E-mail: cchan@ntu.edu.tw Terr. Atmos, directivity, high fault strength, a slapdown phase, and hanging wall effect. The Darfield sequence case

Wu, Yih-Min

275

doi: 10.3319/TAO.2013.05.30.01(T) * Corresponding author  

E-Print Network (OSTI)

doi: 10.3319/TAO.2013.05.30.01(T) * Corresponding author E-mail: drymwu@ntu.edu.tw Terr. Atmos City. The earthquakes occur- ring in southern Taiwan, due to considerable site effects along

Wu, Yih-Min

276

doi: 10.3319/TAO.2013.01.22.01(T) * Corresponding author  

E-Print Network (OSTI)

doi: 10.3319/TAO.2013.01.22.01(T) * Corresponding author E-mail: cchan@ntu.edu.tw Terr. Atmos the path and site effect using ground motion prediction equations, a proba- bilistic seismic hazard

Wu, Yih-Min

277

Correspondences: A personal photographic journey between past/Iran and present/Australia.  

E-Print Network (OSTI)

??This project is an autobiographical photography series entitled: Correspondences; A personal photographic journey between past/Iran and present/Australia. This series of photographs are partly influenced by… (more)

Javan, Katayoun

2013-01-01T23:59:59.000Z

278

Gamma ray bursts and afterglow  

Science Journals Connector (OSTI)

The origin of GRBs have been a mystery for almost 30 years. Their sources emit a huge amount of energy on short time scales and the process involves extreme relativistic motion with bulk Lorentz factor of at least a few hundred. In the last two years “afterglow ” emission in X-ray optical IR and radio was detected. The afterglow can be measured up to months and even years after the few seconds GRB. We review the theory for the ?-rays emission and the afterglow and show that it is strongly supported by observations. A recent detection of optical emission simultaneous with the GRB well agrees with theoretical predictions and further constrains the free parameters of the models. We discuss the evidence that some of the bursts are jets and discuss the prospects of polarization measurements.

Re’em Sari

2000-01-01T23:59:59.000Z

279

Fermi Observations of Gamma-ray Bursts  

SciTech Connect

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.

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

280

Phenomenology of Gamma-Ray Jets  

E-Print Network (OSTI)

We discuss some phenomenological aspects of $\\gamma$-ray emitting jets. In particular, we present calculations of the $\\gamma$-sphere and $\\pi$-sphere for various target photon fields, and employ them to demonstrate how $\\gamma$-ray observations at very high energies can be used to constraint the Doppler factor of the emitting plasma and the production of VHE neutrinos. We also consider the implications of the rapid TeV variability observed in M87 and the TeV blazars, and propose a model for the very rapid TeV flares observed with HESS and MAGIC in some blazars,that accommodates the relatively small Doppler factors inferred from radio observations. Finally, we briefly discuss the prospects for detecting VHE neutrinos from relativistic jets.

Amir Levinson

2007-09-10T23:59:59.000Z

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


281

Pressurised xenon as scintillator for gamma spectroscopy  

E-Print Network (OSTI)

Detectors based on liquid or gas xenon have been used and are in use for a number of applications, in particular for the detection of gamma rays. Xenon is a well-suited medium for gamma spectroscopy thanks to its high atomic number and, consequently, large cross-section for photo-electric absorption. This paper presents experimental studies of high pressure xenon as a scintillator, with the aim of developing a gamma ray detector for the detection of Special Nuclear Materials (SNM). The first goal was to study the dependence of the light yield and of the energy resolution on the thermodynamic conditions. We present preliminary results from an optimised version of the detector.

Resnati, F

2013-01-01T23:59:59.000Z

282

Apparatus and method for detecting gamma radiation  

DOE Patents (OSTI)

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.

Sigg, R.A.

1994-12-13T23:59:59.000Z

283

while ll 6= ERROR do tcl tuple of ctcl corresponding to ll.tid cr  

E-Print Network (OSTI)

corresponding to cdb.tid cr lca #12;rst tuple t of li cl such that t.class >= ca.name caf while lca 6= ERROR and lca.class = ca.name do lia tuple of logical images corresponding to lca.tid cr lcb #12;rst tuple next tuple of li cl in alphabetic order can lca next tuple of li cl in alphabetic order can Plan P4P

Samet, Hanan

284

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

E-Print Network (OSTI)

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.

Andrea Maselli; Valeria Ferrari

2014-02-24T23:59:59.000Z

285

DEVELOPMENT OF A PRECISION TUNABLE GAMMA-RAY SOURCE DRIVEN BY A COMPACT X-BAND LINAC  

SciTech Connect

A precision, tunable gamma-ray source driven by a compact, high-gradient X-band linac is currently under development at LLNL. High-brightness, relativistic electron bunches produced by the linac interact with a Joule-class, 10 ps laser pulse to generate tunable {gamma}-rays in the 0.5-2.5 MeV photon energy range via Compton scattering. The source will be used to excite nuclear resonance fluorescence lines in various isotopes; applications include homeland security, stockpile science and surveillance, nuclear fuel assay, and waste imaging and assay. The source design, key parameters, and current status are presented.

Hartemann, F V; Albert, F; Anderson, G G; Anderson, S G; Bayramian, A J; Betts, S M; Chu, T S; Cross, R R; Ebbers, C A; Fisher, S E; Gibson, D J; Ladran, A S; Messerly, M J; Semenov, V A; Shverdin, M Y; Siders, C W; McNabb, D P; Barty, C J; Vlieks, A E; Jongewaard, E N; Tantawi, S G

2009-04-30T23:59:59.000Z

286

Consistent set of nuclear parameters values for absolute INAA  

SciTech Connect

Gamma spectral analysis of irradiated material can be used to determine absolute disintegration rates for specific radionuclides. These data, together with measured values for the thermal and epithermal neutron fluxes, and irradiation, cooling and counting time values, are all the experimental information required to do absolute Instrumental Neutron Activation Analysis. The calculations required to go from product photon emission rate to target nuclide amount depend upon values used for the thermal neutron capture cross-section, the resonance absorption integral, the half-life and photon branching ratios. Values for these parameters were determined by irradiating and analyzing a series of elemental standards. The results of these measurements were combined with values reported by other workers to arrive at a set of recommended values for the constants. Values for 114 nuclides are listed.

Heft, R.E.

1980-01-01T23:59:59.000Z

287

A supersymmetric model of gamma ray bursts  

E-Print Network (OSTI)

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.

L. Clavelli; G. Karatheodoris

2005-08-08T23:59:59.000Z

288

Redshift indicators for gamma-ray bursts  

E-Print Network (OSTI)

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.

J-L. Atteia

2005-05-04T23:59:59.000Z

289

A review of gamma ray bursts  

Science Journals Connector (OSTI)

Gamma-ray bursts have continued to puzzle astronomers since their discovery thirty years ago. The sources and emission mechanisms are still uncertain. The instruments on the Compton Gamma Ray Observatory most notably BATSE have produced a revolution in our understanding of bursts. BATSE found that the burst spatial distribution was isotropic but inhomogeneous a result inconsistent with any disk population of sources. The currently favored model is one in which the sources lie at cosmological distances. Recent apparent successes in the detection of X-ray and optical counterparts have generated renewed excitement.

Charles Meegan; Kevin Hurley; Alanna Connors; Brenda Dingus; Steven Matz

1997-01-01T23:59:59.000Z

290

A new approach to searching for dark matter signals in Fermi-LAT gamma rays  

SciTech Connect

Several cosmic ray experiments have measured excesses in electrons and positrons, relative to standard backgrounds, for energies from ? 10 GeV–1 TeV. These excesses could be due to new astrophysical sources, but an explanation in which the electrons and positrons are dark matter annihilation or decay products is also consistent. Fortunately, the Fermi-LAT diffuse gamma ray measurements can further test these models, since the electrons and positrons produce gamma rays in their interactions in the interstellar medium. Although the dark matter gamma ray signal consistent with the local electron and positron measurements should be quite large, as we review, there are substantial uncertainties in the modeling of diffuse backgrounds and, additionally, experimental uncertainties that make it difficult to claim a dark matter discovery. In this paper, we introduce an alternative method for understanding the diffuse gamma ray spectrum in which we take the intensity ratio in each energy bin of two different regions of the sky, thereby canceling common systematic uncertainties. For many spectra, this ratio fits well to a power law with a single break in energy. The two measured exponent indices are a robust discriminant between candidate models, and we demonstrate that dark matter annihilation scenarios can predict index values that require ''extreme'' parameters for background-only explanations.

Chang, Spencer [Physics Department, University of California Davis, One Shields Avenue, Davis, CA 95616 (United States); Goodenough, Lisa, E-mail: spchang@ucdavis.edu, E-mail: lcg261@nyu.edu [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States)

2010-08-01T23:59:59.000Z

291

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

E-Print Network (OSTI)

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.

Reetanjali Moharana; Nayantara Gupta

2012-05-27T23:59:59.000Z

292

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

E-Print Network (OSTI)

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.

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

2005-05-26T23:59:59.000Z

293

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

E-Print Network (OSTI)

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

Pijushpani Bhattacharjee; Nayantara Gupta

2003-05-12T23:59:59.000Z

294

Note: Characteristic beam parameter for the line electron gun  

SciTech Connect

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.

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

295

Measurements of the CKM Angle Gamma at BaBar  

SciTech Connect

We present a short review of the measurements of the CKM angle {gamma} performed by the BABAR experiment. We focus on methods using charged B decays, which give a direct access to {gamma} and provide the best constraints so far.

Latour, Emmanuel; /Ecole Polytechnique

2007-10-02T23:59:59.000Z

296

Mono-Energetic Gamma-ray (MEGa-ray)  

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

(MeV) spectral range. MEGa-ray Rendering In the mono-energetic gamma-ray (MEGA-ray) device, electrons and laser photons crash head-on, creating a backscatter of gamma...

297

Coincidence searches of gravitational waves and short gamma-ray bursts  

E-Print Network (OSTI)

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.

Andrea Maselli; Valeria Ferrari

2014-05-28T23:59:59.000Z

298

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

SciTech Connect

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.

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

299

Active Detection and Imaging of Nuclear Materials with High-Brightness Gamma Rays  

SciTech Connect

A Compton scattering {gamma}-ray source, capable of producing photons with energies ranging from 0.1 MeV to 0.9 MeV has been commissioned and characterized, and then used to perform nuclear resonance fluorescence (NRF) experiments. The performances of the two laser systems (one for electron production, one for scattering), the electron photoinjector, and the linear accelerator are also detailed, and {gamma}-ray results are presented. The key source parameters are the size (0.01 mm{sup 2}), horizontal and vertical divergence (6 x 10 mrad{sup 2}), duration (10 ps), spectrum and intensity (10{sup 5} photons/shot). These parameters are summarized by the peak brightness, 1.5 x 10{sup 15} photons/mm{sup 2}/mrad{sup 2}/s/0.1% bandwidth, measured at 478 keV. Additional measurements of the flux as a function of the timing difference between the drive laser pulse and the relativistic photo-electron bunch, {gamma}-ray beam profile, and background evaluations are presented. These results are systematically compared to theoretical models and computer simulations. NRF measurements performed on {sup 7}Li in LiH demonstrate the potential of Compton scattering photon sources to accurately detect isotopes in situ.

Barty, C J; Gibson, D J; Albert, F; Anderson, S G; Anderson, G G; Betts, S M; Berry, R D; Fisher, S E; Hagmann, C A; Johnson, M S; Messerly, M J; Phan, H H; Semenov, V A; Shverdin, M Y; Tremaine, A M; Hartemann, F V; Siders, C W; McNabb, D P

2009-02-26T23:59:59.000Z

300

E-Print Network 3.0 - augments gamma ray-induced Sample Search...  

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

Collection: Mathematics 52 Interesting Interesting Summary: 5 10 15 20 25 (4S) Dataset: ffl 3.3 M B B ffl 4.8 M c c ffl 3.9 M + Gamma Gamma GammaGamma......

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


301

E-Print Network 3.0 - anti-fc gamma receptor Sample Search Results  

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

and Information Sciences 53 Interesting Interesting Summary: 5 10 15 20 25 (4S) Dataset: ffl 3.3 M B B ffl 4.8 M c c ffl 3.9 M + Gamma Gamma GammaGamma......

302

A Gamma-Ray Bursts ’ Fluence-Duration Correlation  

E-Print Network (OSTI)

durations of gamma-ray bursts, and provide arguments that this reflects a correlation between the total

István Horváth; Lajos G. Balázs; Peter Mészáros; Zsolt Bagoly

2005-01-01T23:59:59.000Z

303

HYPERNUCLEAR STRUCTURE FROM GAMMA-RAY SPECTROSCOPY.  

SciTech Connect

The energies of p-shell hypernuclear {gamma} rays obtained from recent experiments using the Hyperball at BNL and KEK are used to constrain the YN interaction which enters into shell-model calculations which include both {Lambda} and {Sigma} configurations.

MILLENER,D.J.

2003-10-14T23:59:59.000Z

304

Laser Electron Gamma Source. Biennial progress report  

SciTech Connect

The LEGS facility provides intense, polarized, monochromatic {gamma}-ray beams by Compton backscattering laser light from relativistic electrons circulating in the X-Ray storage ring of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. With the start of ring operations at 2.8 GeV, LEGS {gamma}-ray energies now extend to 370 MeV. Considerable progress has been made in the development of a new laser system that will increase the beam energies to 470 MeV, and this system is expected to come into operation before the next biennial report. The total flux is administratively held at 6 {times} 10{sup 6} s{sup {minus}1}. The {gamma}-ray energy is determined, with a resolution of 5.5 MeV, by detecting the scattering electrons in a magnetic spectrometer. This spectrometer can `tag` all {gamma}-rays with energies from 185 MeV up to the Compton edge. The beam spot size at the target position is 8 mm (V) {times} 18 mm (H), FWHM. For a single laser wavelength, the linear polarization of the beam is 98% at the Compton edge and decreases to 50% at about 1/2 the energy of the edge. By choosing the laser wavelengths appropriately the polarization can be maintained above 85% throughout the tagging range. During the last two years, experimental running at LEGS occupied an average of 3000 hours annually. Highlights of some of the programs are discussed below.

Sandorfi, A.M. [ed.; Caracappa, A.; Kuczewski, A.; Kistner, O.C.; Lincoln, F.; Miceli, L.; Thorn, C.E. [Brookhaven National Lab., Upton, NY (United States); Hoblit, S. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Physics; Khandaker, M. [Brookhaven National Lab., Upton, NY (United States)]|[Virginia Polytechnic Institute & State Univ., Blacksburg, VA (United States). Dept. of Physics

1994-06-01T23:59:59.000Z

305

Gamma-Ray Bursts: Restarting the Engine  

Science Journals Connector (OSTI)

Recent gamma-ray burst observations have revealed late-time, highly energetic events that deviate from the simplest expectations of the standard fireball picture. Instead, they may indicate that the central engine is active or restarted at late times. We suggest that fragmentation and subsequent accretion during the collapse of a rapidly rotating stellar core offers a natural mechanism for this.

Andrew King; Paul T. O'Brien; Michael R. Goad; Julian Osborne; Emma Olsson; Kim Page

2005-01-01T23:59:59.000Z

306

Neutrino Balls and Gamma-Ray Bursts  

E-Print Network (OSTI)

We propose a mechanism by which the neutrino emission from a supernova-type explosion can be converted into a gamma-ray burst of total energy $\\sim 10^{50}$ ergs. This occurs naturally if the explosion is situated inside a ball of trapped neutrinos, which in turn may lie at a galactic core. There are possible unique signatures of this scenario.

B. Holdom; R. A. Malaney

1993-06-17T23:59:59.000Z

307

Multiple gamma lines from semi-annihilation  

SciTech Connect

Hints in the Fermi data for a 130 GeV gamma line from the galactic center have ignited interest in potential gamma line signatures of dark matter. Explanations of this line based on dark matter annihilation face a parametric tension since they often rely on large enhancements of loop-suppressed cross sections. In this paper, we pursue an alternative possibility that dark matter gamma lines could arise from ''semi-annihilation'' among multiple dark sector states. The semi-annihilation reaction ?{sub i}?{sub j} ? ?{sub k}? with a single final state photon is typically enhanced relative to ordinary annihilation ?{sub i}?-bar {sub i} ? ?? into photon pairs. Semi-annihilation allows for a wide range of dark matter masses compared to the fixed mass value required by annihilation, opening the possibility to explain potential dark matter signatures at higher energies. The most striking prediction of semi-annihilation is the presence of multiple gamma lines, with as many as order N{sup 3} lines possible for N dark sector states, allowing for dark sector spectroscopy. A smoking gun signature arises in the simplest case of degenerate dark matter, where a strong semi-annihilation line at 130 GeV would be accompanied by a weaker annihilation line at 173 GeV. As a proof of principle, we construct two explicit models of dark matter semi-annihilation, one based on non-Abelian vector dark matter and the other based on retrofitting Rayleigh dark matter.

D'Eramo, Francesco [Department of Physics, University of California, Berkeley, CA 94720 (United States); McCullough, Matthew; Thaler, Jesse, E-mail: fraderamo@berkeley.edu, E-mail: mccull@mit.edu, E-mail: jthaler@mit.edu [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

2013-04-01T23:59:59.000Z

308

Gamma-emitting Materials for Industry  

Science Journals Connector (OSTI)

... , p. 717). A paper dealing with the supply and uses of radium and radon for industry is now being distributed by the Ministry to trade associations, professional institutes ... Points of interest arising from this paper are the different physical properties of radium and radon. Though they both emit gamma-rays of identical quality, the radiation of the former ...

1949-06-04T23:59:59.000Z

309

Gamma Ray Imaging for Environmental Remediation  

SciTech Connect

This program is the development of germanium strip detectors for environmental remediation. It is a collaboration between the Naval Research Laboratory and Lawrence Berkeley National Lab. The goal is to develop detectors that are simultaneously capable of excellent spectroscopy and imaging of gamma radiation.

B.F. Philips; R.A. Kroeger: J.D. Kurfess: W.N. Johnson; E.A. Wulf; E. I. Novikova

2004-11-12T23:59:59.000Z

310

Performance and safety parameters for the high flux isotope reactor  

SciTech Connect

A Monte Carlo depletion model for the High Flux Isotope Reactor (HFIR) Cycle 400 and its use in calculating parameters of relevance to the reactor performance and safety during the reactor cycle are presented in this paper. This depletion model was developed to serve as a reference for the design of a low-enriched uranium (LEU) fuel for an ongoing study to convert HFIR from high-enriched uranium (HEU) to LEU fuel; both HEU and LEU depletion models use the same methodology and ENDF/B-VII nuclear data as discussed in this paper. The calculated HFIR Cycle 400 parameters, which are compared with measurement data from critical experiments performed at HFIR, data included in the HFIR Safety Analysis Report (SAR), or data reported by previous calculations, provide a basis for verification or updating of the corresponding SAR data. (authors)

Ilas, G. [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831-6172 (United States); Primm III, T. [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831-6172 (United States); Primm Consulting, LLC, 945 Laurel Hill Road, Knoxville, TN 37923 (United States)

2012-07-01T23:59:59.000Z

311

Observations of cosmic gamma ray sources and their contribution to the diffuse gamma ray background  

SciTech Connect

The objective is to study soft gamma ray emission in the 0.1 to 10 MeV energy band for selected active galactic nuclei and explore how much they contribute to the total diffuse gamma ray background. A series of imaging observations of extragalactic objects in the low energy gamma-ray region were carried out by the Coded Aperture Directional Gamma-ray Telescope (DGT). The DGT was successfully flown at stratospheric balloon altitudes, and observations were made of the Crab, NGC 1275, MKN 421, and NGC 4151. The measured Crab spectrum is consistent with a featureless power-law of the form. Significant emission was detected up to 500 keV from the Seyfert galaxy, NGC 4151. To increase the total sky exposure the extragalactic field images were analyzed, including the 3C 273 region, obtained by the DGT.

Bhattacharya, D.

1990-01-01T23:59:59.000Z

312

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

E-Print Network (OSTI)

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

Tomonori Totani

1998-10-14T23:59:59.000Z

313

Measuring the charged pion polarizability in the gamma gamma -> pi+pi- reaction  

SciTech Connect

Development has begun of a new experiment to measure the charged pion polarizability $\\alpha_{\\pi}-\\beta_{\\pi}$. The charged pion polarizability ranks among the most important tests of low-energy QCD presently unresolved by experiment. Analogous to precision measurements of $\\pi^{\\circ}\\rightarrow\\gamma\\gamma$ that test the intrinsic odd-parity (anomalous) sector of QCD, the pion polarizability tests the intrinsic even-parity sector of QCD. The measurement will be performed using the $\\gamma\\gamma\\rightarrow\\pi^{+{}}\\pi^{-{}}$ cross section accessed via the Primakoff mechanism on nuclear targets using the GlueX detector in Hall D at Jefferson Lab. The linearly polarized photon source in Hall-D will be utilized to separate the Primakoff cross-section from coherent $\\rho^{\\circ}$ production.

Lawrence, David W. [JLAB; Miskimen, Rory A. [University of Massachusetts, Amherst; Mushkarenkov, Alexander Nikolaevich [University of Massachusetts, Amherst; Smith, Elton S. [JLAB

2013-08-01T23:59:59.000Z

314

The Biggest Bangs The Mystery of Gamma-Ray Bursts,  

E-Print Network (OSTI)

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

Katz, Jonathan I.

315

The Biggest Bangs The Mystery of Gamma-Ray Bursts,  

E-Print Network (OSTI)

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

Katz, Jonathan I.

316

Gamma-Ray Bursts Nuclear Test Ban Treaty, 1963  

E-Print Network (OSTI)

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

Harrison, Thomas

317

Gamma ray bursts observed with WATCH?EURECA  

Science Journals Connector (OSTI)

The WATCH wide field x?ray monitor has the capability of independently locating bright Gamma Ray Bursts to 1° accuracy. We report the preliminary positions of 12 Gamma Ray Bursts observed with the WATCH monitor flown on the ES spacecraft EURECA during its 11 month mission. Also the recurrence of the Soft Gamma Repeater SGR 1900+14 in 1992 is verified.

S. Brandt; N. Lund; A. J. Castro?Tirado

1994-01-01T23:59:59.000Z

318

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

E-Print Network (OSTI)

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...

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

319

A complete sample of long bright Swift gamma ray bursts  

Science Journals Connector (OSTI)

...complete sample of long bright Swift gamma ray bursts Gianpiero Tagliaferri 1 Ruben...subsample of Swift long bright gamma ray bursts (GRBs). The sample, made...correlations and the nature of dark bursts. gamma ray bursts|complete sample|luminosity...

2013-01-01T23:59:59.000Z

320

Gamma-ray bursts spectral correlations and their cosmological use  

Science Journals Connector (OSTI)

...research-article Discussion Meeting Issue Gamma-ray bursts organized by Alan Wells, Ralph...J. Wijers and Martin Rees Gamma-ray bursts spectral correlations and their...correlations involving the long-gamma-ray bursts (GRBs) prompt emission energy...

2007-01-01T23:59:59.000Z

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


321

Gamma-ray bursts, QSOs and active galaxies  

Science Journals Connector (OSTI)

...research-article Discussion Meeting Issue Gamma-ray bursts organized by Alan Wells, Ralph...J. Wijers and Martin Rees Gamma-ray bursts, QSOs and active galaxies Geoffrey...of the absorption spectra of gamma-ray burst (GRB) sources or afterglows...

2007-01-01T23:59:59.000Z

322

Short gamma-ray bursts near and far  

Science Journals Connector (OSTI)

...research-article Discussion Meeting Issue Gamma-ray bursts organized by Alan Wells, Ralph...Wijers and Martin Rees Short gamma-ray bursts near and far Andrew J Levan...understanding the nature of short gamma-ray bursts (GRBs) has been rapid since...

2007-01-01T23:59:59.000Z

323

TERRESTRIAL GAMMA-RAY FLASH PRODUCTION BY LIGHTNING  

E-Print Network (OSTI)

TERRESTRIAL GAMMA-RAY FLASH PRODUCTION BY LIGHTNING A DISSERTATION SUBMITTED TO THE DEPARTMENT gamma-ray flashes (TGFs) are brief flashes of gamma-rays originating in the Earth's atmosphere) that extends from below 25 keV to above 20 MeV. When good lightning data exists, TGFs are closely associated

324

Branching fraction and photon energy spectrum for b -> s gamma  

E-Print Network (OSTI)

theory corrections. We obtain first and second moments of the photon energy spectrum above 2.0 GeV, (E gamma) = 2.346 +/- 0.032 +/- 0.011 GeV, and (E-gamma(2)) - (E-gamma)(2) = 0.0226 +/- 0.0066 +/- 0.0020 GeV2, where the errors are statistical...

Ammar, Raymond G.; Bean, Alice; Besson, David Zeke; Zhao, X.

2001-12-01T23:59:59.000Z

325

CONSTRAINTS ON THE SYNCHROTRON EMISSION MECHANISM IN GAMMA-RAY BURSTS  

SciTech Connect

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.

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

326

Data Corresponding to 2010 Renewable Energy Data Book | OpenEI  

Open Energy Info (EERE)

Data Corresponding to 2010 Renewable Energy Data Book Data Corresponding to 2010 Renewable Energy Data Book Dataset Summary Description The US Department of Energy (DOE), via the office of Energy Efficiency and Renewable Energy (EERE), publishes an annual Renewable Energy Data Book. Provided here is the data corresponding to the 2010 Renewable Energy Data Book. The types of data available include: US energy production and consumption (2000 - 2009) for all fuel sources (coal, natural gas, petroleum, nuclear, hydro, and non-hydro renewables); total consumption by sector; US renewable energy capacity and generation (2000 - 2009); as well as global renewable energy capacity and generation (2000 - 2009). Source NREL Date Released August 01st, 2010 (4 years ago) Date Updated Unknown Keywords coal consumption

327

X-Ray Spectral Parameters for a Sample of 95 Active Galactic Nuclei  

E-Print Network (OSTI)

We present a broadband X-ray analysis of a new homogeneous sample of 95 active galactic nuclei (AGN) from the 22-month Swift/BAT all-sky survey. For this sample we treated jointly the X-ray spectra observed by XMM-Newton and INTEGRAL missions for the total spectral range of 0.5-250 keV. Photon index \\Gamma, relative reflection R, equivalent width of Fe $K_{\\alpha}$ line (EW Fe $K_{\\alpha}$), hydrogen column density $N_{H}$, exponential cut-off energy $E_{c}$ and intrinsic luminosity $L_{corr}$ are determined for all objects of the sample. We investigated correlations \\Gamma - R, EW Fe $K_{\\alpha}$ - $L_{corr}$, \\Gamma - $E_{c}$, EW Fe $K_{\\alpha}$ - $N_{H}$. Dependence \\Gamma - R for Seyfert 1 and 2 type of galaxies has been investigated separately. We found that the relative reflection parameter at low power-law indexes for Seyfert 2 galaxies is systematically higher than for Seyfert 1 ones. This can be related to an increasing contribution of the reflected radiation from the gas-dust torus. Our data show th...

Vasylenko, A; Fedorova, E

2015-01-01T23:59:59.000Z

328

Exclusive Measurements of the b to s gamma Transition Rate and Photon Energy Spectrum  

SciTech Connect

We use 429 fb{sup -1} of e{sup +}e{sup -} collision data collected at the {Upsilon}(4S) resonance with the BABAR detector to measure the radiative transition rate of b {yields} 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 {Beta}({bar B} {yields} Xs{gamma}) = (3.29 {+-} 0.19 {+-} 0.48) x 10{sup -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{sub b} and {mu}{sub {pi}}{sup 2}, in the kinetic and shape function models.

Lees, J.P.; Poireau, V.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Palano, A.; /Bari U. /INFN, Bari; Eigen, G.; Stugu, B.; /Bergen U.; Brown, David Nathan; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; /LBL, Berkeley /UC, Berkeley; Koch, H.; Schroeder, T.; /Ruhr U., Bochum; Asgeirsson, D.J.; Hearty, C.; Mattison, T.S.; McKenna, J.A.; /British Columbia U.; Khan, A.; /Brunel U.; Blinov, V.E.; Buzykaev, A.R.; /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. /Ferrara U. /INFN, Ferrara /Frascati /Genoa U. /INFN, Genoa /Indian Inst. Tech., Guwahati /Harvard U. /Harvey Mudd Coll. /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 /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U., Comp. Sci. Dept. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /Milan U. /INFN, Milan /Mississippi U. /Montreal U. /Naples U. /INFN, Naples /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U.; /more authors..

2012-08-30T23:59:59.000Z

329

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

SciTech Connect

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.

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

330

Improved methods for detecting gravitational waves associated with short gamma-ray bursts  

E-Print Network (OSTI)

In the era of second generation ground-based gravitational wave detectors, short gamma-ray bursts (GRBs) will be among the most promising astrophysical events for joint electromagnetic and gravitational wave observation. A targeted search for gravitational wave compact binary merger signals in coincidence with short GRBs was developed and used to analyze data from the first generation LIGO and Virgo instruments. In this paper, we present improvements to this search that enhance our ability to detect gravitational wave counterparts to short GRBs. Specifically, we introduce an improved method for estimating the gravitational wave background to obtain the event significance required to make detections; implement a method of tiling extended sky regions, as required when searching for signals associated to poorly localized GRBs from Fermi Gamma-ray Burst Monitor or the InterPlanetary Network; and incorporate astrophysical knowledge about the beaming of GRB emission to restrict the search parameter space. We descri...

Williamson, A R; Fairhurst, S; Harry, I W; Macdonald, E; Macleod, D; Predoi, V

2014-01-01T23:59:59.000Z

331

X(3): An exactly separable {gamma}-rigid version of the X(5) critical point symmetry  

SciTech Connect

A {gamma}-rigid version (with {gamma} = 0) of the X(5) critical point symmetry is constructed. The model, to be called X(3) since it is proved to contain three degrees of freedom, utilizes an infinite well potential, is based on exact separation of variables, and leads to parameter-free (up to overall scale factors) predictions for spectra and B(E2) transition rates which are in good agreement with existing experimental data for {sup 172}Os and {sup 186}Pt. An unexpected similarity of the {beta}{sub 1} bands of the X(5) nuclei {sup 150}Nd, {sup 152}Sm, {sup 154}Gd, and {sup 156}Dy to the X(3) predictions is observed.

Bonatsos, D., E-mail: bonat@inp.demokritos.gr; Lenis, D., E-mail: lenis@inp.demokritos.gr; Petrellis, D. [N.C.S.R., Institute of Nuclear Physics (Greece)], E-mail: petrellis@inp.demokritos.gr; Yigitoglu, I. [Istanbul University, Hasan Ali Yucel Faculty of Education (Turkey)], E-mail: yigitoglu@istanbul.edu.tr

2007-09-15T23:59:59.000Z

332

MilagroA TeV Observatory for Gamma Ray Bursts  

E-Print Network (OSTI)

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

California at Santa Cruz, University of

333

Generalized Macdonald polynomials, spectral duality for conformal blocks and AGT correspondence in five dimensions  

E-Print Network (OSTI)

We study five dimensional AGT correspondence by means of the q-deformed beta-ensemble technique. We provide a special basis of states in the q-deformed CFT Hilbert space consisting of generalized Macdonald polynomials, derive the loop equations for the beta-ensemble and obtain the factorization formulas for the corresponding matrix elements. We prove the spectral duality for Nekrasov functions and discuss its meaning for conformal blocks. We also clarify the relation between topological strings and q-Liouville vertex operators.

Zenkevich, Yegor

2014-01-01T23:59:59.000Z

334

Generalized Macdonald polynomials, spectral duality for conformal blocks and AGT correspondence in five dimensions  

E-Print Network (OSTI)

We study five dimensional AGT correspondence by means of the q-deformed beta-ensemble technique. We provide a special basis of states in the q-deformed CFT Hilbert space consisting of generalized Macdonald polynomials, derive the loop equations for the beta-ensemble and obtain the factorization formulas for the corresponding matrix elements. We prove the spectral duality for Nekrasov functions and discuss its meaning for conformal blocks. We also clarify the relation between topological strings and q-Liouville vertex operators.

Yegor Zenkevich

2014-12-30T23:59:59.000Z

335

Shock Hugoniots of molecular liquids and the principle of corresponding states  

SciTech Connect

We observe that the shock velocity-particle velocity Hugoniots for various liquids (e.g. nitrogen, oxygen, carbon dioxide, argon) lie almost on top of one another. Recalling the work of Ross and Ree [J. Chem. Phys. 73, 6146-6152 (1980)], we hypothesize that these materials obey a principle of corresponding states. We use the principle to deduce how the Hugoniots of two corresponding materials should be related, and we compare the results with data and find good agreement. We suggest this as a method for estimating the Hugoniot of a material of the appropriate type in the absence of shock data, and we illustrate with fluorine.

Chisolm, Eric D [Los Alamos National Laboratory; Crockett, Scott D [Los Alamos National Laboratory; Shaw, Milton S [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

336

Microsoft Word - Y12GammaAppendicesAand B.doc  

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

A: Distributions of Quarterly Gamma Doses by Year A: Distributions of Quarterly Gamma Doses by Year Note change in vertical scale, frequency or number of workers having dose of a given range. Vertical axis ranges 0 - 100 for 1952-60 and 0 - 4000 for 1961-79 corresponding to policy change in 1961 to monitoring all Y-12 workers for external radiation. Quarter= 1 N= 206 Zeros= 62 ( 30.1 %) Max Dose= 825 Dose(mrem) Frequency 0 200 400 600 800 0 20 40 60 80 Quarter= 2 N= 253 Zeros= 89 ( 35.2 %) Max Dose= 1702 Dose(mrem) Frequency 0 200 400 600 800 0 20 40 60 80 Quarter= 3 N= 308 Zeros= 82 ( 26.6 %) Max Dose= 1945 Dose(mrem) Frequency 0 200 400 600 800 0 20 40 60 80 Quarter= 4 N= 386 Zeros= 182 ( 47.2 %) Max Dose= 2174 Dose(mrem) Frequency 0 200 400 600 800 0 20 40 60 80 Quarterly Y-12 Film Badge Gamma Dose for 1952 Note change in vertical scale, frequency or number of workers having dose of a given

337

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

DOE Patents (OSTI)

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.

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

2011-09-13T23:59:59.000Z

338

Measuring neutrino oscillation parameters using $\  

SciTech Connect

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.

Backhouse, Christopher James; /Oxford U.

2011-02-01T23:59:59.000Z

339

On detecting oscillations of gamma rays into axion-like particles in turbulent and coherent magnetic fields  

E-Print Network (OSTI)

Background radiation fields pervade the Universe, and above a certain energy any $\\gamma$-ray flux emitted by an extragalactic source should be attenuated due to $e^+e^-$ pair production. The opacity could be alleviated if photons oscillated into hypothetical axion-like particles (ALPs) in ambient magnetic fields, leading to a $\\gamma$-ray excess especially at high optical depths that could be detected with imaging air Cherenkov telescopes (IACTs). Here, we introduce a method to search for such a signal in $\\gamma$-ray data and to estimate sensitivities for future observations. Different magnetic fields close to the $\\gamma$-ray source are taken into account in which photons can convert into ALPs that then propagate unimpeded over cosmological distances until they re-convert in the magnetic field of the Milky Way. Specifically, we consider the coherent field at parsec scales in a blazar jet as well as the turbulent field inside a galaxy cluster. For the latter, we explicitly derive the transversal components of a magnetic field with gaussian turbulence which are responsible for the photon-ALP mixing. To illustrate the method, we apply it to a mock IACT array with characteristics similar to the Cherenkov Telescope Array and investigate the dependence of the sensitivity to detect a $\\gamma$-ray excess on the magnetic-field parameters.

Manuel Meyer; Daniele Montanino; Jan Conrad

2014-09-04T23:59:59.000Z

340

Multi-parameter on-line coal bulk analysis  

SciTech Connect

This was a four-year grant that was given a no cost extension for one more year. The purpose of the grant was to develop a pulsed neutron-based technique that could measure on-line all the major and minor elements in coal. Such measurements would allow the continuous monitoring of bulk parameters such as coal heating value (BTU/lb), volatile matter, moisture etc., deemed important to the coal industry. Such parameters, along with the continuous measurement of elements such as sulfur and sodium, are of major economic and environmental concern, and their measurement would assist in a more efficient use of the coal-fired boilers, as well as limiting emissions controlled by the 1990 Clean Air Act Amendments. It was hoped that this study would lead to the development of a technique able to create a marketable product, an On-Line Elemental Coal Analyzer. The study was separated in the following major parts: (1) Devise an efficient system for the detection of gamma rays; (2) Prior to experimentation, perform modeling and simulations for items such as detector shielding, coal sample configuration, and neutron tube collimation; (3) Develop a computer code for data reduction and analysis; (4) Measure the elemental composition of various coal samples; and (5) Design a prototype, on-line elemental coal analyzer, based on the PFTNA principle.

NONE

1999-02-01T23:59:59.000Z

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


341

correspondence NATURE|VOL424|17JULY2003|www.nature.com/nature 251  

E-Print Network (OSTI)

correspondence NATURE|VOL424|17JULY2003|www.nature.com/nature 251 Looking into the safety of AAV vectors Sir -- The News story "Harmful potential of viral vectors fuels doubts over gene therapy" (Nature (H. Nakai et al. Nature Genet. 34, 297­302; 2003), we would like to emphasize

Kay, Mark A.

342

correspondence n engl j med 363;16 nejm.org october 14, 2010 1583  

E-Print Network (OSTI)

correspondence n engl j med 363;16 nejm.org october 14, 2010 1583 blood pressureTrials.gov number, NCT00608049). Frank M. Sacks, M.D. Hannia Campos, Ph.D. Harvard School of Public Health Boston potential conflict of interest. 1. Reducing salt intake in populations: report of a WHO forum and technical

Paris-Sud XI, Université de

343

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

344

Scientific Correspondence Are Natural Deep Eutectic Solvents the Missing Link in  

E-Print Network (OSTI)

Scientific Correspondence Are Natural Deep Eutectic Solvents the Missing Link in Understanding in the biochemistry of cells and organisms. The theory is based on analogy with green chemistry, where in past years and deep eutectic solvents (DES) have been revisited by chemical engineering, because such solvents can

Galis, Frietson

345

Comparison of Correspondence Analysis Methods for Synonymous Codon Usage in Bacteria  

E-Print Network (OSTI)

Comparison of Correspondence Analysis Methods for Synonymous Codon Usage in Bacteria Haruo SUZUKI 21 June 2008; accepted 24 September 2008) Abstract Synonymous codon usage varies both between sources of variation in synonymous codon usage among genes and provides a way to identify horizontally

Forney, Larry J.

346

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

E-Print Network (OSTI)

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 exchangers with round tubes, such as charge reduction and higher heat transfer efficiency. But a reduced

Paris-Sud XI, Université de

347

Four-point vector correlators and AdS/QCD correspondence  

E-Print Network (OSTI)

We derive the four-point vector correlators in QCD from AdS/QCD correspondence. It is shown that meson poles are correctly reproduced. The final expression also suggests a nonzero amplitude in the limit of zero virtuality of two longitudinal gluons. This fact does not mean that one can produce, absorb or scatter real longitudinal gluons.

Konyushikhin, Maxim

2009-01-01T23:59:59.000Z

348

Further correspondences between plane piezoelectricity and generalized plane strain in elasticity  

Science Journals Connector (OSTI)

...conditions which do not vary along the generator. We show that our previous correspondence...lateral surface which do not vary along the generators. It was proven that when the piezoelectric...4.4) in which Bi is the magnetic induction, Hi is the magnetic field intensity...

1998-01-01T23:59:59.000Z

349

Geotagged Photo Recognition using Corresponding Aerial Photos with Multiple Kernel Learning  

E-Print Network (OSTI)

Geotagged Photo Recognition using Corresponding Aerial Photos with Multiple Kernel Learning Keita for geotagged photos, we have already proposed ex- ploiting aerial photos around geotag places as addi- tional image features for visual recognition of geo- tagged photos. In the previous work, to fuse two kinds

Yanai, Keiji

350

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

E-Print Network (OSTI)

* Corresponding author. Solar Energy Materials & Solar Cells 58 (1999) 209}218 A highly e solar cells based on the CdTe/CdS heterojunction still exhibits quite a few open problems$cient and stable CdTe/CdS thin "lm solar cell N. Romeo, A. Bosio, R. Tedeschi*, A. Romeo, V. Canevari Dipartimento

Romeo, Alessandro

351

nature geoscience | VOL 3 | JUNE 2010 | www.nature.com/naturegeoscience 375 correspondence  

E-Print Network (OSTI)

nature geoscience | VOL 3 | JUNE 2010 | www.nature.com/naturegeoscience 375 correspondence.001), which suggests that novel mechanisms may be responsible. Methane is an important greenhouse gas3 is often cited among the triggers or added factors in a cascade of effects leading to climate fluctuations3

Vermont, University of

352

* Corresponding author. E-mail address: dengx@physics.utoledo.edu (X. Deng)  

E-Print Network (OSTI)

.2% e$ciency for 1 ft 2 solar panels [3] and 8% stable e$ciency for 4 ft 2 production scale PV modules* Corresponding author. E-mail address: dengx@physics.utoledo.edu (X. Deng) Solar Energy Materials & Solar Cells 62 (2000) 89}95 Amorphous silicon and silicon germanium materials for high-e$ciency triple

Deng, Xunming

353

NOTES AND CORRESPONDENCE Changes of the Boreal Winter Hadley Circulation in the NCEPNCAR and ECMWF  

E-Print Network (OSTI)

NOTES AND CORRESPONDENCE Changes of the Boreal Winter Hadley Circulation in the NCEP­NCAR and ECMWF show a strengthening of the atmospheric Hadley circulation in boreal winter over the last 50 years on the difference of these trends in the two reanalyses. It is shown that trends in the Hadley circulation

Zhang, Minghua

354

*Correspondence address: Department of Nuclear Science, National Tsinghua University, Hsinchu, Taiwan 30043.  

E-Print Network (OSTI)

for laser-driven, electron acceleration in a structure-loaded vacuum is being carried out at Stanford accelerator boundaries in a vacuum. The distance between two adjacent ac- celerator cell boundaries is less*Correspondence address: Department of Nuclear Science, National Tsinghua University, Hsinchu

Byer, Robert L.

355

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

E-Print Network (OSTI)

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

Kellis, Manolis

356

Exploring and quantifying the `co-variability' of the extremes corresponding to different climate components  

E-Print Network (OSTI)

Exploring and quantifying the `co-variability' of the extremes corresponding to different climate to the fact that there might be moisture-temperature feedback that has further implications on the extremes. Having said, we aim to study how extreme precipitation and temperature co-vary and are determined

Miami, University of

357

Redshifts of the Long Gamma-Ray Bursts  

E-Print Network (OSTI)

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.

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

2007-04-06T23:59:59.000Z

358

Bulk-edge correspondence in (2?+?1)-dimensional Abelian topological phases  

Science Journals Connector (OSTI)

The same bulk two-dimensional topological phase can have multiple distinct, fully chiral edge phases. We show that this can occur in the integer quantum Hall states at ?=8 and 12, with experimentally testable consequences. We show that this can occur in Abelian fractional quantum Hall states as well, with the simplest examples being at ?=87,1211,815,165. We give a general criterion for the existence of multiple distinct chiral edge phases for the same bulk phase and discuss experimental consequences. Edge phases correspond to lattices while bulk phases correspond to genera of lattices. Since there are typically multiple lattices in a genus, the bulk-edge correspondence is typically one-to-many; there are usually many stable fully chiral edge phases corresponding to the same bulk. We explain these correspondences using the theory of integral quadratic forms. We show that fermionic systems can have edge phases with only bosonic low-energy excitations and discuss a fermionic generalization of the relation between bulk topological spins and the central charge. The latter follows from our demonstration that every fermionic topological phase can be represented as a bosonic topological phase, together with some number of filled Landau levels. Our analysis shows that every Abelian topological phase can be decomposed into a tensor product of theories associated with prime numbers p in which every quasiparticle has a topological spin that is a pnth root of unity for some n. It also leads to a simple demonstration that all Abelian topological phases can be represented by U(1)N Chern-Simons theory parameterized by a K matrix.

Jennifer Cano; Meng Cheng; Michael Mulligan; Chetan Nayak; Eugeniu Plamadeala; Jon Yard

2014-03-14T23:59:59.000Z

359

SuperAGILE and Gamma Ray Bursts  

SciTech Connect

The solid-state hard X-ray imager of AGILE gamma-ray mission -- SuperAGILE -- has a six arcmin on-axis angular resolution in the 15-45 keV range, a field of view in excess of 1 steradian. The instrument is very light: 5 kg only. It is equipped with an on-board self triggering logic, image deconvolution, and it is able to transmit the coordinates of a GRB to the ground in real-time through the ORBCOMM constellation of satellites. Photon by photon Scientific Data are sent to the Malindi ground station at every contact. In this paper we review the performance of the SuperAGILE experiment (scheduled for a launch in the middle of 2006), after its first onground calibrations, and show the perspectives for Gamma Ray Bursts.

Pacciani, Luigi; Costa, Enrico; Del Monte, Ettore; Donnarumma, Immacolata; Evangelista, Yuri; Feroci, Marco; Frutti, Massimo; Lazzarotto, Francesco; Lapshov, Igor; Rubini, Alda; Soffitta, Paolo; Tavani, Marco [IASF-INAF Rome (Italy); Barbiellini, Guido [INFN Trieste (Italy); Mastropietro, Marcello [CNR Montelibretti (Italy); Morelli, Ennio [IASF-INAF-Bologna (Italy); Rapisarda, Massimo [ENEA Frascati (Italy)

2006-05-19T23:59:59.000Z

360

Factorization in B ---> V gamma decays  

SciTech Connect

The factorization properties of the radiative decays B {yields} V{gamma} are analyzed at leading order in 1/m{sub b} using the soft-collinear effective theory. It is shown that the decay amplitudes can be expressed in terms of a B {yields} V form factor evaluated at q{sup 2} = 0, light-cone distribution amplitudes of the B and V mesons, and calculable hard-scattering kernels. The renormalization-group equations in the effective theory are solved to resum perturbative logarithms of the different scales in the decay process. Phenomenological implications for the B {yields} K*{gamma} branching ratio, isospin asymmetry, and CP asymmetries are discussed, with particular emphasis on possible effects from physics beyond the Standard Model.

Becher, Thomas; /Fermilab; Hill, Richard J.; /SLAC; Neubert, Matthias; /Cornell U., LEPP

2005-03-01T23:59:59.000Z

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


361

Lorentz violation from gamma-ray bursts  

E-Print Network (OSTI)

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.

Shu Zhang; Bo-Qiang Ma

2014-06-18T23:59:59.000Z

362

Gamma ray bursts: A 1983 overview  

Science Journals Connector (OSTI)

Gamma?ray burst observations are reviewed with mention of new gamma?ray and optical transient measurements and with discussions of the controversial contradictory and unresolved issues that have recently emerged: burst spectra appear to fluctuate in time as rapidly as they are measured implying that any one spectrum may be incorrect; energy spectra can be obligingly fitted to practically any desired shape implying in effect that no objective spectral resolution exists at all; burst fluxes and temporal quantities including the total event energy are characterized very differently with differing instruments implying that even elementary knowledge of their properties is instrumentally subjective; finally the log N?log S determinations are deficient in the weak bursts while there is no detection of a source direction anisotropy implying that Ptolemy was right or that burst source distance estimates are basically guesswork. These issues may remain unsolved until vastly improved instruments are flown.

T. L. Cline

1984-01-01T23:59:59.000Z

363

Compositions containing poly ([gamma]glutamylcysteinyl)glycines  

DOE Patents (OSTI)

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.

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

1992-02-18T23:59:59.000Z

364

Neutron-driven gamma-ray laser  

DOE Patents (OSTI)

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.

Bowman, Charles D. (Los Alamos, NM)

1990-01-01T23:59:59.000Z

365

Factorization in B to V gamma Decays  

SciTech Connect

The factorization properties of the radiative decays B {yields} V{gamma} are analyzed at leading order in 1/mb using the soft-collinear effective theory. It is shown that the decay amplitudes can be expressed in terms of a B {yields} V form factor evaluated at q{sup 2} = 0, light-cone distribution amplitudes of the B and V mesons, and calculable hard-scattering kernels. The renormalization-group equations in the effective theory are solved to resume perturbative logarithms of the different scales in the decay process. Phenomenological implications for the B {yields} K*{gamma} branching ratio, isospin asymmetry, and CP asymmetries are discussed, with particular emphasis on possible effects from physics beyond the Standard Model.

Becher, T

2005-03-28T23:59:59.000Z

366

Gamma irradiation effects in W films  

SciTech Connect

Using the van Der Pauw methodology, the surface resistivity of irradiated tungsten films deposited on Silicon substrate was measured. The films were exposed to {gamma} radiation using a isotopic {sup 60}Co source in three irradiation stages attaining 40.35 kGy in total dose. The obtained results for superficial resistivity display a time annealing features and their values are proportional to the total dose.

Claro, Luiz H. [Instituto de Estudos Avancados - IEAv, Rod. dos Tamoios, km 5,5, CEP: 12228-840, Sao Jose dos Campos, SP (Brazil) and Faculdade de Tecnologia Sao Francisco - FATESF, Av. Siqueira Campos, 1174, CEP: 12207-000, Jacarei (Brazil); Santos, Ingrid A. [Instituto de Estudos Avancados - IEAv, Rod. dos Tamoios, km 5,5, CEP: 12228-840, Sao Jose dos Campos, SP (Brazil); Silva, Cassia F. [Faculdade de Tecnologia Sao Francisco - FATESF, Av. Siqueira Campos, 1174, CEP: 12207-000, Jacarei, SP (Brazil)

2013-05-06T23:59:59.000Z

367

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

SciTech Connect

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.

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

368

The Galactic gamma-ray club  

E-Print Network (OSTI)

The exclusive Galactic gamma-ray club has opened up to new members. Supernova remnants, pulsar wind nebulae, and massive binary systems hosting a compact object have recently joined the young pulsars as firmly established sources of gamma rays in the Milky Way. Massive young stellar clusters are on the waiting list to join the club. Only the fine imaging recently obtained at TeV energies could resolve specific sources. The samples are sparse, but raise exciting questions. The jet or pulsar-wind origin of the emission in binaries has been hotly debated, but it seems that both types of systems have been recently detected. The nature of the radiation in shock accelerators is still questioned: do nuclei contribute a lot, a little, or not to the gamma rays and what energy do they carry away from the shock budget? The acceleration process and the structural evolution of the pulsar winds are still uncertain. The magnetic field distribution in all these systems is a key, but poorly constrained, ingredient to model the multi-wavelength data, particle transport and electron ageing. It must, however, be determined in order to efficiently probe particle distributions and the acceleration mechanisms. The source samples soon to be expected from GLAST and the Cherenkov telescopes should bring new valuable test cases and they will, for the first time, shed statistical light on the collective behaviour of these different types of accelerators.

Isabelle A. Grenier

2008-04-02T23:59:59.000Z

369

Remnants from Gamma-Ray Bursts  

Science Journals Connector (OSTI)

We model the intermediate-time evolution of a "jetted" gamma-ray burst (GRB) as two blobs of matter colliding with the interstellar medium. We follow the hydrodynamic evolution of this system numerically and calculate the bremsstrahlung and synchrotron images of the remnant. We find that for a burst energy of 1051 ergs the remnant becomes spherical after ~5000 yr, when it has collected ~50 M? of interstellar mass. This result is independent of the exact details of the GRB, such as the opening angle. After this time a gamma-ray burst remnant has an expanding sphere morphology. The similarity to a supernova remnant makes it difficult to distinguish between the two at this stage. The expected number of nonspherical gamma-ray burst remnants is ~0.05 per galaxy for a beaming factor of 0.01 and a burst energy of 1051 ergs. Our results suggest that the double-shell object DEM L316 is not a GRB remnant.

Shai Ayal; Tsvi Piran

2001-01-01T23:59:59.000Z

370

Solution To The Gamma Ray Burst Mystery?  

E-Print Network (OSTI)

Photoexcitation and ionization of partially ionized heavy atoms in highly relativistic flows by interstellar photons, followed by their reemission in radiative recombination and decay, boost star-light into beamed $\\gamma$ rays along the flow direction. Repeated excitation/decay of highly relativistic baryonic ejecta from merger or accretion induced collapse of neutron stars in dense stellar regions (DSRs), like galactic cores, globular clusters and super star-clusters, can convert enough kinetic energy in such events in distant galaxies into cosmological gamma ray bursts (GRBs). The model predicts remarkably well all the main observed temporal and spectral properties of GRBs. Its success strongly suggests that GRBs are $\\gamma$ ray tomography pictures of DSRs in galaxies at cosmological distances with unprecedented resolution: A time resolution of $dt\\sim 1~ms$ in a GRB can resolve stars at a Hubble distance which are separated by only $D\\sim 10^{10}cm$. This is equivalent to the resolving power of an optical telescope with a diameter larger than one Astronomical Unit!

Nir J. Shaviv; Arnon Dar

1996-08-21T23:59:59.000Z

371

Measurement of the total hadronic cross section in tagged. gamma. gamma. reactions  

SciTech Connect

We present a measurement of the total cross section for {gamma}{gamma}{r arrow}hadrons, with one photon quasireal and the other a spacelike photon of mass squared {minus}{ital Q}{sup 2}. Results are presented as a function of {ital Q}{sup 2} and the {gamma}{gamma} center-of-mass energy {ital W}, with the {ital Q}{sup 2} range extending from 0.2 to 60 GeV{sup 2}, and {ital W} in the range from 2 to 10 GeV. The data were taken with the TPC/Two-Gamma facility at the SLAC {ital e}{sup +}{ital e}{sup {minus}} storage ring PEP, which was operated at a beam energy of 14.5 GeV. The cross section exhibits a gentle falloff with increasing {ital W}. Its {ital Q}{sup 2} dependence is shown to be well described by an incoherent sum of vector-meson and pointlike scattering over most of the observed {ital W} range. Agreement at high {ital Q}{sup 2} is improved if a minimum-{ital p}{sub {ital T}} cutoff (motivated by QCD) is imposed on the pointlike contribution.

Aihara, H.; Alston-Garnjost, M.; Avery, R.E.; Barker, A.R.; Bauer, D.A.; Bay, A.; Belcinski, R.; Bingham, H.H.; Bloom, E.D.; Buchanan, C.D.; Caldwell, D.O.; Chao, H.; Chun, S.; Clark, A.R.; Cowan, G.D.; Crane, D.A.; Dahl, O.I.; Daoudi, M.; Derby, K.A.; Eastman, J.J.; Eberhard, P.H.; Edberg, T.K.; Eisner, A.M.; Erne, F.C.; Fairfield, K.H.; Fridman, A.; Godfrey, G.; Hauptman, J.M.; Ho, C.; Hofmann, W.; Kamae, T.; Kenney, R.W.; Khacheryan, S.; Kofler, R.R.; Lambert, D.J.; Langeveld, W.G.J.; Layter, J.G.; Lin, W.T.; Linde, F.L.; Loken, S.C.; Lu, A.; Lynch, G.R.; Lys, J.E.; Madaras, R.J.; Magnuson, B.D.; Marsiske, H.; Masek, G.E.; Mathis, L.G.; Maxfield, S.J.; McNeil, R.R.; Miller, E.S.; Nicol, N.A.; Nygren, D.R.; Oddone, P.J.; Oh, H.; Oyang, Y.; Paar, H.P.; Palounek, A.P.T.; Park, S.K.; Pellett, D.E.; Pripstein, M.; Ronan, M.T.; Ross, R.R.; Rouse, F.R.; Schwitkis, K.A.; Sens, J.C.; Shapiro, G.; Shen, B.C.; Smith, J.R.; Steinman, J.S.; Stephens, R.W.; Stevenson, M.L.; Stork, D.H.; Strauss,; TPC /Two-Gamma Collaboration

1990-05-01T23:59:59.000Z

372

Proposed ILC Parameters T.O. Raubenheimer  

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

-05-98 -05-98 Proposed ILC Parameters T.O. Raubenheimer and K. Yokoya Introduction In this note, we describe the proposed working parameter set for the KEK-SLAC ILC linear collider and discuss the reasons leading to the values listed; more ex- tensive discussion of the optimization process will be found in subsequent notes. The parameter set is listed in Table 1 and is compared with the JLC 3-97 parameters and the NLC ZDR parameters in Table 2. The new parameter set has an operating plane which ranges from low IP emittances and high luminosity (cases A) to large IP emittances and smaller luminosity (cases C). Over this range, the bunch charge, bunch length, and IP beta functions are varied, however, the parameters have been chosen so that the tolerances on the accelerating structures are roughly constant. The collider must be designed to operate over the entire parameter range. In all cases,

373

Parameters Identification for Motorcycle Simulator's Platform Characterization  

E-Print Network (OSTI)

Parameters Identification for Motorcycle Simulator's Platform Characterization L. Nehaoua H modeling and parameters identification of a motorcycle simulator's platform. This model begins with some (cars and motorcycles) is possible by taking in care some characteristics of land vehicles. Indeed

Paris-Sud XI, Université de

374

Planet Parameters in Microlensing Events  

E-Print Network (OSTI)

A planetary microlensing event occurs when a planet perturbs one of the two images created in a point-mass microlensing event, causing a deviation from the standard Paczy\\'nski curve. Determination of the two physical parameters that can be extracted from a planetary microlensing event, the planet/star mass ratio q, and the planet/star separation in units of the stellar Einstein ring, $y_p$, is hampered by several types of degeneracies. There are two distinct and qualitatively different classes of planetary events: major and minor image perturbations. For major image perturbations, there is a potentially crippling continuous degeneracy in q which is of order $\\delta_d^{-1}$, where $\\delta_d$ is the maximum fractional deviation of the planetary perturbation. Since the threshold of detection is expected to be $\\delta_d \\sim 5%$, this degeneracy in q can be a factor of $\\sim 20$. For minor image perturbations, the continuous degeneracy in q is considerably less severe, and is typically less than a factor 4. We show that these degeneracies can be resolved by observations from dedicated telescopes on several continents together with optical/infrared photometry from one of these sites. There also exists a class of discrete degeneracies. These are typically easy to resolve given good temporal coverage of the planetary event. Unambiguous interpretation of planetary microlensing events requires the resolution of both types of degeneracy. We describe the degeneracies in detail and specify the situations in which they are problematic. We also describe how individual planet masses and physical projected separations can be measured.

B. Scott Gaudi; Andrew Gould

1996-10-16T23:59:59.000Z

375

Correspondence Between $5D$ Ricci-Flat Cosmological Models and Quintessence Dark Energy Models  

E-Print Network (OSTI)

We study the accelerating expansion and the induced dark energy of the $5D$ Ricci-flat universe which is characterized by having a big bounce as opposed to a big bang. We show that the arbitrary function $\\mu(t)$ contained in the $5D$ solutions can be rewritten in terms of the redshift $z$ as a new arbitrary function $f(z)$, and we find that there is a correspondence between this $f(z)$ and the potential $V(\\phi)$ of the 4D quintessence models. Using this correspondence, the arbitrary function $f(z)$ and the $5D$ solution could be specified for a given form of the potential $V(\\phi)$.

Lixin Xu; Hongya Liu; Baorong Chang

2005-12-26T23:59:59.000Z

376

The $Z_H \\to \\gamma H$ decay in the Littlest Higgs Model  

E-Print Network (OSTI)

We present the calculation of the $Z_H \\to \\gamma H$ decay in the context of the Littlest Higgs model at one-loop level. Our calculations include the contributions of fermions, scalars and gauge bosons in accordance with the most recent experimental constraints on the parameters space of the model. We find branching ratios of the order of $10^{-5}$ for the energy scale $f=2,3,4$ TeV on the $0.1energy of 14 TeV. By using the integrated luminosity projected for the Large Hadron Collider in the last stage of operation, we estimated the number of events for this process.

Aranda, J I; Ramírez-Zavaleta, F; Tututi, E S

2015-01-01T23:59:59.000Z

377

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

E-Print Network (OSTI)

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.

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

378

Gamma spectroscopic measurements using the PID350 pixelated CdTe radiation detector  

E-Print Network (OSTI)

Spectroscopic measurements are presented using the PID350 pixelated gamma radiation detectors. A high-speed data acquisition system has been developed in order to reduce the data loss during the data reading in case of a high flux of photons. A data analysis framework has been developed in order to improve the resolution of the acquired energy spectra, using specific calibration parameters for each PID350's pixel. Three PID350 detectors have been used to construct a stacked prototype system and spectroscopic measurements have been performed in order to test the ability of the prototype to localize radioactive sources.

Karafasoulis, K; Seferlis, S; Papadakis, I; Loukas, D; Lambropoulos, C; Potiriadis, C

2010-01-01T23:59:59.000Z

379

Free Parameters and Frameworks in Minimal Supersymmetry  

E-Print Network (OSTI)

405 Appendix A Free Parameters and Frameworks in Minimal Supersymmetry It is useful to discuss what the various schemes that exist for reducing the set of free parameters to a manageable number. The information, and so is fixed by experiment. The free parameters consist mainly of the coe#cients of the ``soft

California at Berkeley, University of

380

Free Parameters and Frameworks in Minimal Supersymmetry  

E-Print Network (OSTI)

405 Appendix A Free Parameters and Frameworks in Minimal Supersymmetry It is useful to discuss what the various schemes that exist for reducing the set of free parameters to a manageable number. The information, and so is fixed by experiment. The free parameters consist mainly of the coefficients of the "soft

California at Berkeley, University of

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381

The off-shell axial anomaly via the {gamma}*{pi}{sup 0} {yields} {gamma} transition  

SciTech Connect

The {gamma}*{pi}{sup 0} {yields} {gamma} form factor, including the extension off the pion mass-shell, is obtained from a generalized impulse approximation within a QCD-based model field theory known to provide an excellent description of the pion charge form factor. This approach implements dressing of the vertex functions and propagators consistent with dynamical chiral symmetry breaking, gauge invariance, quark confinement and perturbative QCD. Soft nonperturbative behavior, dictated by the axial anomaly, is found to evolve to the perturbative QCD limit only for Q{sup 2} {ge} 20 GeV{sup 2}.

Frank, M.R. [Univ. of Washington, Seattle, WA (United States). Institute for Nuclear Theory; Mitchell, K.L.; Tandy, P.C. [Kent State Univ., OH (United States); Roberts, C.D. [Argonne National Lab., IL (United States)

1995-01-01T23:59:59.000Z

382

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

SciTech Connect

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.

Brunk, J.L.

1995-09-01T23:59:59.000Z

383

Application of the gamma evaluation method in Gamma Knife film dosimetry  

SciTech Connect

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.

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

384

Searches for Lepton Flavor Violation in the Decays tau+- ---> e+- gamma and tau+- ---> mu+- gamma  

SciTech Connect

Searches for lepton-flavor-violating decays of a {tau} lepton to a lighter mass lepton and a photon have been performed with the entire dataset of (963 {+-} 7) x 10{sup 6} {tau} decays collected by the BABAR detector near the {Upsilon}(4S), {Upsilon}(3S) and {Upsilon}(2S) resonances. The searches yield no evidence of signals and they set upper limits on the branching fractions of {Beta}({tau}{sup {+-}} {yields} e{sup {+-}}{gamma}) < 3.3 x 10{sup -8} and {Beta}({tau}{sup {+-}} {yields} {mu}{sup {+-}}{gamma}) < 4.4 x 10{sup -8} at 90% confidence level.

Aubert, Bernard; Karyotakis, Y.; Lees, J.P.; Poireau, V.; Prencipe, E.; Prudent, X.; 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, David Nathan; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; /LBL, Berkeley /UC, Berkeley /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, San Diego /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 /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT, LNS; /more authors.; ,

2010-06-11T23:59:59.000Z

385

Luminosity function and jet structure of Gamma Ray Bursts  

E-Print Network (OSTI)

The structure of Gamma Ray Burst (GRB) jets impacts on their prompt and afterglow emission properties. The jet of GRBs could be uniform, with constant energy per unit solid angle within the jet aperture, or it could instead be structured, namely with energy and velocity that depend on the angular distance from the axis of the jet. We try to get some insight about the still unknown structure of GRBs by studying their luminosity function. We show that low (1e46-1e48 erg/s) and high (i.e. with L > 1e50 erg/s) luminosity GRBs can be described by a unique luminosity function, which is also consistent with current lower limits in the intermediate luminosity range (1e48-1e50} erg/s). We derive analytical expressions for the luminosity function of GRBs in uniform and structured jet models and compare them with the data. Uniform jets can reproduce the entire luminosity function with reasonable values of the free parameters. A structured jet can also fit adequately the current data, provided that the energy within the ...

Pescalli, A; Salafia, O S; Ghisellini, G; Nappo, F; Salvaterra, R

2014-01-01T23:59:59.000Z

386

Efficiency and spectrum of internal gamma-ray burst shocks  

E-Print Network (OSTI)

We present an analysis of the Internal Shock Model of GRBs, where gamma-rays are produced by internal shocks within a relativistic wind. We show that observed GRB characteristics impose stringent constraints on wind and source parameters. We find that a significant fraction, of order 20 %, of the wind kinetic energy can be converted to radiation, provided the distribution of Lorentz factors within the wind has a large variance and provided the minimum Lorentz factor is higher than 10^(2.5)L_(52)^(2/9), where L=10^(52)L_(52)erg/s is the wind luminosity. For a high, >10 %, efficiency wind, spectral energy breaks in the 0.1 to 1 MeV range are obtained for sources with dynamical time R/c energies in this range. The lower limit to wind Lorenz factor and the upper limit, around (R/10^7 cm)^(-5/6) MeV to observed break energies are set by Thomson optical depth due to electron positron pairs produced by synchrotron photons. Natural consequences of the model are absence of bursts with peak emission energy significantly exceeding 1 MeV, and existence of low luminosity bursts with low, 1 keV to 10 keV, break energies.

D. Guetta; M. Spada; E. Waxman

2000-11-08T23:59:59.000Z

387

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

E-Print Network (OSTI)

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...

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

388

Chapter 10 - Cross-Subject Comparison of Local Diffusion MRI Parameters  

Science Journals Connector (OSTI)

Abstract There has been much interest in using magnetic resonance diffusion imaging to provide information about anatomical connectivity in the brain by measuring the anisotropic diffusion of water in white matter tracts. One of the measures most commonly derived from diffusion data is fractional anisotropy (FA), which quantifies how strongly directional the local tract structure is. Many imaging studies are starting to use FA images (and other diffusion-derived parameters) in voxelwise statistical analyses, in order to localize brain changes related to development, degeneration, and disease. However, in order to compare such local changes in diffusion parameters across subjects, it is necessary to solve the “correspondence problem,” to determine which location in each subject’s diffusion images corresponds to the equivalent anatomical location in the other subjects. Some researchers have used generic registration methods to try to achieve correspondence, some have used region-of-interest approaches, some have used tractography to parameterize diffusion parameters according to anatomical location, and some have combined different aspects of all of these approaches to attempt to achieve robust and accurate correspondence. This chapter describes many such approaches in the literature, discusses the potential richness available when using more diffusion-derived information than purely the FA, and also illustrates some of the dangers that the researcher should be aware of when interpreting the analysis of multi-subject diffusion MRI studies.

Stephen M. Smith; Gordon Kindlmann; Saad Jbabdi

2014-01-01T23:59:59.000Z

389

GAMQUEST, a Computer Program to Identify Gamma Rays  

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

GAMQUEST GAMQUEST A Computer Program to Identify Gamma Rays Edgardo Browne, Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 EBROWNE@LBL.Gov Table of Contents Introduction. Program Access and Output Files. How to Run GAMQUEST. From Individual Accounts. From Guest Account. Gamma-Ray Data. GAMQUEST, a Tool for Applied Research. Searching Strategies. Examples. Neutron Activation Analysis. Gamma-Ray Spectrum Between 100 and 800 keV. Gamma-Ray Spectrum Between 800 and 1600 keV. A List of X Rays and Gamma Rays from the Decay of 192Ir (74 hr). Run GAMQUEST from Guest Account Acknowledgments. References. 1. Introduction. The characteristic energies and intensities of gamma rays emitted by radioactive isotopes are commonly used as fingerprints for isotope

390

Gamma-ray burst data from DMSP satellites  

SciTech Connect

A number of gamma-ray bursts have been detected by means of gamma-ray detectors aboard three Air Force Defense Meteorological Satellite Program (DMSP) satellites, in polar orbits at 800 km altitude. The gamma-ray data have a 2-second resolving time, and are usually telemetered in 5 energy bins in the range 50--1000 keV. Although it is not possible to detect gamma-ray bursts when the DMSP satellites are passing through the radiation belt or the South Atlantic Anomaly, or when the source is obscured by the Earth, a number of gamma-ray bursts have been detected by two or even three of the satellites. The DMSP data may be of considerable, assistance in evaluating time histories, locations, and spectra of gamma-ray bursts.

Terrell, J.; Klebesadel, R.W.; Lee, P. (Los Alamos National Lab., NM (United States)); Griffee, J.W. (Sandia National Labs., Albuquerque, NM (United States))

1991-01-01T23:59:59.000Z

391

Gamma-ray burst data from DMSP satellites  

SciTech Connect

A number of gamma-ray bursts have been detected by means of gamma-ray detectors aboard three Air Force Defense Meteorological Satellite Program (DMSP) satellites, in polar orbits at 800 km altitude. The gamma-ray data have a 2-second resolving time, and are usually telemetered in 5 energy bins in the range 50--1000 keV. Although it is not possible to detect gamma-ray bursts when the DMSP satellites are passing through the radiation belt or the South Atlantic Anomaly, or when the source is obscured by the Earth, a number of gamma-ray bursts have been detected by two or even three of the satellites. The DMSP data may be of considerable, assistance in evaluating time histories, locations, and spectra of gamma-ray bursts.

Terrell, J.; Klebesadel, R.W.; Lee, P. [Los Alamos National Lab., NM (United States); Griffee, J.W. [Sandia National Labs., Albuquerque, NM (United States)

1991-12-31T23:59:59.000Z

392

Gamma Log At Coso Geothermal Area (1977) | Open Energy Information  

Open Energy Info (EERE)

Gamma Log At Coso Geothermal Area (1977) Gamma Log At Coso Geothermal Area (1977) Jump to: navigation, search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Gamma Log At Coso Geothermal Area (1977) Exploration Activity Details Location Coso Geothermal Area Exploration Technique Gamma Log Activity Date 1977 Usefulness not indicated DOE-funding Unknown Notes extensive geophysical logging surveys were conducted: natural gamma and neutron porosity logs indicate gross rock type References Galbraith, R. M. (1 May 1978) Geological and geophysical analysis of Coso Geothermal Exploration Hole No. 1 (CGEH-1), Coso Hot Springs KGRA, California Goranson, C.; Schroeder, R. (1 June 1978) Static downhole characteristics of well CGEH-1 at Coso Hot Springs, China Lake, California Retrieved from "http://en.openei.org/w/index.php?title=Gamma_Log_At_Coso_Geothermal_Area_(1977)&oldid=510780"

393

Gamma-ray Bursts as Probes of Galaxy Evolution  

E-Print Network (OSTI)

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

Â?umer, Slobodan

394

Nuclear Criticality as a Contributor to Gamma Ray Burst Events  

E-Print Network (OSTI)

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.

Robert Bruce Hayes

2013-01-15T23:59:59.000Z

395

Gamma Ray Bursts with (and without) Supernova Fireworks  

Science Journals Connector (OSTI)

We review the observational status of the Supernova/Gamma?Ray Burst connection. Observations of long duration Gamma?ray bursts suggest that they are associated with bright SNe?Ic. However recent observations of GRB 060614 puzzle this scenario pointing out the existence of long?duration Gamma?ray Burst not accompanied by a bright supernova. Current estimates of the SN and GRB rates yield a ratio GRB/SNe?Ibc in the range ?0.4%–3%.

Massimo Della Valle

2008-01-01T23:59:59.000Z

396

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

E-Print Network (OSTI)

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.

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

1994-11-25T23:59:59.000Z

397

Measurement of the eta_b(1S) mass and the branching fraction for Upsilon(3S) --> gamma eta_b(1S)  

E-Print Network (OSTI)

We report evidence for the ground state of bottomonium, eta_b(1S), in the radiative decay Upsilon(3S) --> gamma eta_b in e^+e^- annihilation data taken with the CLEO III detector. Using 6 million Upsilon(3S) decays, and assuming Gamma(eta_b) = 10 MeV/c^2, we obtain B(Upsilon(3S) --> gamma eta_b) = (7.1 +- 1.8 +- 1.1) X 10^{-4}, where the first error is statistical and the second is systematic. The statistical significance is about 4 sigma. The mass is determined to be M(eta_b) = 9391.8 +- 6.6 +- 2.0 MeV/c^2, which corresponds to the hyperfine splitting Delta M_{hf}(1S)_b = 68.5 +- 6.6 +- 2.0 MeV/c^2. Using 9 million Upsilon(2S) decays, we place an upper limit on the corresponding Y(2S) decay, B(Y(2S) --> gamma eta_b) < 8.4 X 10^{-4} at 90 % confidence level.

The CLEO Collaboration; G. Bonvicini; D. Cinabro; A. Lincoln; M. J. Smith; P. Zhou; J. Zhu; P. Naik; J. Rademacker; D. M. Asner; K. W. Edwards; J. Reed; A. N. Robichaud; G. Tatishvili; E. J. White; R. A. Briere; H. Vogel; P. U. E. Onyisi; J. L. Rosner; J. P. Alexander; D. G. Cassel; R. Ehrlich; L. Fields; R. S. Galik; L. Gibbons; S. W. Gray; D. L. Hartill; B. K. Heltsley; J. M. Hunt; D. L. Kreinick; V. E. Kuznetsov; J. Ledoux; H. Mahlke-Krüger; J. R. Patterson; D. Peterson; D. Riley; A. Ryd; A. J. Sadoff; X. Shi; S. Stroiney; W. M. Sun; J. Yelton; P. Rubin; N. Lowrey; S. Mehrabyan; M. Selen; J. Wiss; M. Kornicer; R. E. Mitchell; M. R. Shepherd; C. M. Tarbert; D. Besson; T. K. Pedlar; J. Xavier; D. Cronin-Hennessy; K. Y. Gao; J. Hietala; R. Poling; P. Zweber; S. Dobbs; Z. Metreveli; K. K. Seth; B. J. Y. Tan; A. Tomaradze; S. Brisbane; J. Libby; L. Martin; A. Powell; P. Spradlin; C. Thomas; G. Wilkinson; H. Mendez; J. Y. Ge; D. H. Miller; I. P. J. Shipsey; B. Xin; G. S. Adams; D. Hu; B. Moziak; J. Napolitano; K. M. Ecklund; J. Insler; H. Muramatsu; C. S. Park; E. H. Thorndike; F. Yang; M. Artuso; S. Blusk; S. Khalil; R. Mountain; K. Randrianarivony; T. Skwarnicki; J. C. Wang; L. M. Zhang

2009-09-30T23:59:59.000Z

398

Measurement of CP observables in B+- --> D_CP K+- decays and constraints on the CKM angle gamma  

E-Print Network (OSTI)

Using the entire sample of 467 million Y(4S) --> BBbar decays collected with the BaBar detector at the PEP-II asymmetric-energy B factory at SLAC, we perform a "GLW" analysis of B+- --> D K+- decays, using decay modes in which the neutral D meson decays to either CP-eigenstates or non-CP-eigenstates. We measure the partial decay rate charge asymmetries for CP-even and CP-odd D final states to be A_CP+ = 0.25+-0.06+-0.02 and A_CP- = -0.09+-0.07+-0.02, respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter A_CP+ is different from zero with a significance of 3.6 standard deviations, constituting evidence for direct CP violation. We also measure the ratios of the charged-averaged B partial decay rates in CP and non-CP decays, R_CP+ = 1.18+-0.09+-0.05 and R_CP- = 1.07+-0.08+-0.04. We infer frequentist confidence intervals for the angle gamma of the (db) unitarity triangle, for the strong phase difference delta_B, and for the amplitude ratio r_B, which are related to the B- --> DK- decay amplitude by r_Be^{i(delta_B-gamma)} = A(B- --> anti-D0 K^-)/A(B- --> D0 K-). Including statistical and systematic uncertainties, we obtain 0.24gamma < 22.7 degrees or 80.9 degrees < gamma < 99.1 degrees or 157.3 degrees < gamma < 168.7 degrees (7.0 degrees < gamma < 173.0 degrees) at the 68% (95%) confidence level.

The BABAR Collaboration; P. del Amo Sanchez

2010-07-03T23:59:59.000Z

399

Neutron and gamma radiation effects in proton exchanged optical waveguides  

Science Journals Connector (OSTI)

The effect of neutron and gamma ray irradiations on the optical properties of proton exchanged Z-cut lithium niobate optical planar waveguides were investigated. The damage thresholds...

Passaro, Vittorio; Armenise, Mario

2002-01-01T23:59:59.000Z

400

The Diverse Environments of Gamma-Ray Bursts.  

E-Print Network (OSTI)

??I present results from several years of concerted observations of the afterglows and host galaxies of gamma-ray bursts (GRBs), the most energetic explosions in the… (more)

Perley, Daniel Alan

2011-01-01T23:59:59.000Z

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


401

A Closer Look at a Gamma-Ray Burst  

E-Print Network (OSTI)

A study of gamma rays produced when stars collapse or collide reveals details of the explosion mechanism, particularly the role of magnetic fields.

S. Covino

2007-05-05T23:59:59.000Z

402

Behavior of sigma(gamma p) at Large Coherence Lengths  

E-Print Network (OSTI)

Various parametrizations of sigma(gamma p) are tried out on the small-x fixed target and HERA data. A two-Pomeron type parametrization is found to give the best reproduction of the data. The data indicate that the value of lambda(eff) for parametrizations of the form sigma(gamma p)~l^lambda(eff) approaches a constant value at high Q^2. The extrapolated values of sigma(gamma p) to very long coherence lengths are found to cross in some parametrizations for l>10^7 fm, indicating the possibility that sigma(gamma p) becomes Q^2 independent at large values of the coherence length l.

Allen Caldwell

2008-02-06T23:59:59.000Z

403

Inelastic cross sections from gamma-ray measurements  

SciTech Connect

Measurements of gamma rays following neutron induced reactions have been studied with the Germanium Array for Neutron-induced Excitations (GEANIE) at the Los Alamos Neutron Science Center (LANSCE) for many years. Gamma-ray excitation functions and coincidence studies provide insight into nuclear reaction mechanisms as well as expanding our knowledge of energy levels and gamma-rays. Samples studied with Ge detectors at LANSCE range from Be to Pu. Fe, Cr and Ti have been considered for use as reference cross sections. An overview of the measurements and efforts to create a reliable neutron-induced gamma-ray reference cross section will be presented.

Nelson, Ronald Owen [Los Alamos National Laboratory

2010-12-06T23:59:59.000Z

404

Can Naked Singularities Yield Gamma Ray Bursts?  

E-Print Network (OSTI)

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

H. M. Antia

1998-07-09T23:59:59.000Z

405

Gamma Ray Burst Neutrinos Probing Quantum Gravity  

E-Print Network (OSTI)

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.

M. C. Gonzalez-Garcia; F. Halzen

2006-11-28T23:59:59.000Z

406

Gamma irradiation of the prenatal mouse dentition  

E-Print Network (OSTI)

as the dental lamina to the stage of the deposition of enamel and dentin. The purpose of this study was to determine the effect of a continuous stress of gamma irradiation on the structure of the odontogenic cells, the relative size and rate of development... development. In 1927, Leist (9) made a study of the effect of X-rays on teeth, which was brought about by the following rase. A worker in a Roentgen tube factory was exposed daily to a considerable dose of X-irradiation. Sometime later he began to show...

Kerley, Michael Auston

1969-01-01T23:59:59.000Z

407

Gamma ray bursts and spectral features  

Science Journals Connector (OSTI)

The situation concerning the presence of features in gamma ray burst (GRB) spectra is analyzed taking into account recent results obtained especially with the PHOBOS probes and GINGA satellite. If the existence of cyclotron features seems now to be generally accepted the situation for the other features reported around 400?500 keV is not completely clarified. The presence of such features is discussed. Moreover some aspects of the high and low energy variations in the GRB and on the characteristics of their total spectrum are also reviewed. Finally future missions which might have a great impact in the GRB spectral analysis will be shortly considered.

E. Jourdain

1991-01-01T23:59:59.000Z

408

Gamma Ray Bursts as Cosmological Probes  

Science Journals Connector (OSTI)

We discuss the prospects of using Gamma Ray Bursts (GRBs) as high?redshift distance estimators and consider their use in the study of two dark energy models the Generalized Chaplygin Gas (GCG) a model for the unification of dark energy and dark matter and the XCDM model a model where a generic dark energy fluid like component is described by the equation of state p = ??. Given that the GRBs range of redshifts is rather high it turns out that they are not very sensitive to the dark energy component being however fairly good estimators of the amount of dark matter in the Universe.

O. Bertolami; P. T. Silva

2006-01-01T23:59:59.000Z

409

Gamma Ray Bursts In Their Historic Context  

Science Journals Connector (OSTI)

Gamma ray bursts remained essentially non?understood or misunderstood from their 1973 discovery (not I will claim “serendipitous”) to the first 1997 redshift. This is by no means a record. The poster explored some of the examples of longer?standing puzzles and the after?dinner talk some of the details of the GRB case. The most striking feature of the GRB history is probably the unanimity with which “all we like sheep went astray ” which followed the epoch of “we have turned everyone to his own way.” Some of the reasons for this the range of hypotheses and how GRBs were presented to the astronomical and larger communities are discussed.

Virginia Trimble

2004-01-01T23:59:59.000Z

410

Covariance Analysis of Gamma Ray Spectra  

SciTech Connect

The covariance method exploits fluctuations in signals to recover information encoded in correlations which are usually lost when signal averaging occurs. In nuclear spectroscopy it can be regarded as a generalization of the coincidence technique. The method can be used to extract signal from uncorrelated noise, to separate overlapping spectral peaks, to identify escape peaks, to reconstruct spectra from Compton continua, and to generate secondary spectral fingerprints. We discuss a few statistical considerations of the covariance method and present experimental examples of its use in gamma spectroscopy.

Trainham, R.; Tinsley, J.

2013-01-01T23:59:59.000Z

411

Neutrino Event Rates from Gamma Ray Bursts  

E-Print Network (OSTI)

We recalculate the diffuse flux of high energy neutrinos produced by Gamma Ray Bursts (GRB) in the relativistic fireball model. Although we confirm that the average single burst produces only ~10^{-2} high energy neutrino events in a detector with 1 km^2 effective area, i.e. about 10 events per year, we show that the observed rate is dominated by burst-to-burst fluctuations which are very large. We find event rates that are expected to be larger by one order of magnitude, likely more, which are dominated by a few very bright bursts. This greatly simplifies their detection.

F. Halzen; D. W. Hooper

1999-08-12T23:59:59.000Z

412

Impact of gamma-V vertex corrections on the V-P-gamma transition form factors  

E-Print Network (OSTI)

The aim of this paper is to present an effective field theory description of the conversion transition of the vector meson V into the pseudoscalar P and the lepton-pair l+l-. The normalized form factor for omega to pi^0 gamma^ast transition is presented and compared to the available data and to the predictions of other models.

Sergii Raspopov

2014-02-06T23:59:59.000Z

413

The Animated Gamma-ray Sky Revealed by the Fermi Gamma-ray Space Telescope  

ScienceCinema (OSTI)

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.

Isabelle Grenier

2010-01-08T23:59:59.000Z

414

Compton scattering effects on the duration of terrestrial gamma-ray flashes  

E-Print Network (OSTI)

; 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

Pasko, Victor

415

OBSERVATIONS OF THE PROMPT GAMMA-RAY EMISSION OF GRB 070125 Eric C. Bellm,1  

E-Print Network (OSTI)

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

California at Berkeley, University of

416

Study of Celestial Objects with Very High Energy Gamma Rays CANGAROO III  

E-Print Network (OSTI)

), 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

Enomoto, Ryoji

417

X-RAYRICH GAMMA-RAY BURSTS, PHOTOSPHERES, AND VARIABILITY P. Meszaros,1,2  

E-Print Network (OSTI)

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

Zhang, Bing

418

Search for GeV Emission from Gamma-Ray Bursts Using Milagro Scaler Data  

E-Print Network (OSTI)

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

California at Santa Cruz, University of

419

Verification of Gamma Knife extend system based fractionated treatment planning using EBT2 film  

SciTech Connect

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.

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

420

Strategy to detect the gravitational radiation counterpart of gamma-ray bursts  

E-Print Network (OSTI)

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.

S. Bonazzola; E. Gourgoulhon

1998-01-16T23:59:59.000Z

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


421

D-instantons probing D3-branes and the AdS-CFT correspondence  

Science Journals Connector (OSTI)

D-instantons are considered as a probe of coinciding N D3-branes. They can feel an external metric via the commutator terms in their effective action. We show that when the D-instantons are separated from the D3-branes, the metric which is probed at the one loop level, exactly coincides with that of the Bogomol’nyi-Prasad-Sommerfield Ramond-Ramond 3-brane. An interesting connection of this result to the possible explanation of the AdS-CFT correspondence within Ishibashi-Kawai-Kitazawa-Tsuchiba M(atrix) theory is discussed.

E. T. Akhmedov

1999-04-16T23:59:59.000Z

422

Fusion of Baxter's Elliptic $R$-matrix and the Vertex-Face Correspondence  

E-Print Network (OSTI)

The matrix elements of the $2\\times 2$ fusion of Baxter's elliptic $R$-matrix, $R^{(2,2)}(u)$, are given explicitly. Based on a note by Jimbo, we give a formula which show that $R^{(2,2)}(u)$ is gauge equivalent to Fateev's $R$-matrix for the 21-vertex model. Then the crossing symmetry formula for $R^{(2,2)}(u)$ is derived. We also consider the fusion of the vertex-face correspondence relation and derive a crossing symmetry relation between the fusion of the intertwining vectors and their dual vectors.

Hitoshi Konno

2005-03-31T23:59:59.000Z

423

Ray-wave correspondence in the nonlinear description of stadium-cavity lasers  

E-Print Network (OSTI)

We show that the solution of fully nonlinear lasing equations for stadium cavities exhibits a highly directional emission pattern. This directionality can be well explained by a ray-dynamical model, where the dominant ray-escape dynamics is governed by the unstable manifolds of the unstable short periodic orbits for the stadium cavity. Investigating the cold-cavity modes relevant for the lasing, we found that all of the high-Q modes have the emission directionality corresponding to that of the ray-dynamical model.

Susumu Shinohara; Takahisa Harayama; Hakan E. Tureci; A. Douglas Stone

2006-09-28T23:59:59.000Z

424

Observational Constraints on Cosmological Models with the Updated Long Gamma-Ray Bursts  

E-Print Network (OSTI)

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.

Hao Wei

2010-08-16T23:59:59.000Z

425

Design of a 2 MeV Compton scattering gamma-ray source for DNDO missions  

SciTech Connect

Nuclear resonance fluorescence-based isotope-specific detection and imaging is a powerful new technology that can enable access to new mission spaces for DNDO. Within this context, the development of advanced mono-energetic gamma ray sources plays an important role in the DNDO R&D portfolio, as it offers a faster, more precise, and safer alternative to conventional Bremsstrahlung sources. In this report, a specific design strategy is presented, along with a series of theoretical and computational tools, with the goal of optimizing source parameters for DNDO applications. In parallel, key technologies are outlined, along with discussions justifying specific choices and contrasting those with other alternatives. Finally, a complete conceptual design is described, and machine parameters are presented in detail.

Hartemann, F V; Albert, F

2009-08-24T23:59:59.000Z

426

Low latency search for gravitational waves from black-hole–neutron-star binaries in coincidence with short gamma-ray bursts  

Science Journals Connector (OSTI)

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 semianalytic 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 are measured with high accuracy, it will be possible to use this information to trigger the search for off-axis gamma-ray burst afterglows.

Andrea Maselli and Valeria Ferrari

2014-03-24T23:59:59.000Z

427

THE BRIGHT GAMMA-RAY BURST OF 2000 FEBRUARY 10: A CASE STUDY OF AN OPTICALLY DARK GAMMA-RAY BURST  

E-Print Network (OSTI)

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

Fynbo, Johan

428

Photon interaction parameters of some spin ice compound materials  

Science Journals Connector (OSTI)

Spin ice compounds (SICs) are the frustrated magnetic materials which are used in nuclear reactor control system and semiconductor electronic circuits. Photon interaction parameters such as the effective atomic number, Zeff, and the effective electron density, Neff, for SICs such as Dy2Ti2O7, Dy2Sn2O7, Ho2Ti2O7 and Ho2Sn2O7 have been computed at photon energies from 10 keV to 100 GeV. The Zeff of the spin ice compounds is approximately constant in energy range 0.3–4 MeV where Compton scattering is the main photon interaction process. The Zeff increases sharply below 0.3 MeV due to photoelectric absorption process and above 3 MeV due to pair-production process. The well type structures of Zeff and Neff for HSO and DSO have been observed in the photon energy range 30-60 keV due to involvement of k-shell electron in the interaction. Dy2Sn2O7 and Ho2Sn2O7 are suitable materials for gamma shielding.

Vishwanath P. Singh; N.M. Badiger

2012-01-01T23:59:59.000Z

429

Adjustable Robust Parameter Design with Unknown Distributions  

E-Print Network (OSTI)

Mar 27, 2013 ... Adjustable Robust Parameter Design with Unknown Distributions. ihsan Yanikoglu(i.yanikoglu ***at*** uvt.nl) Dick den Hertog(d.denhertog ...

ihsan Yanikoglu

2013-03-27T23:59:59.000Z

430

Thermal Hydraulic Simulations, Error Estimation and Parameter  

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

Error Estimation and Parameter Sensitivity Studies in Drekar::CFD Thomas M. Smith, John N. Shadid, Roger P. Pawlowski, Eric C. Cyr and Timothy M. Wildey Sandia National...

431

GRB 020410: A Gamma-ray burst afterglow discovered by its supernova light  

E-Print Network (OSTI)

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

2004-01-01T23:59:59.000Z

432

Compton Recoil Electron Tracking With the TIGRE Gamma-Ray Balloon Experiment  

E-Print Network (OSTI)

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

Kamiya, Kaoru

2011-01-01T23:59:59.000Z

433

E-Print Network 3.0 - atmospheric gamma-ray imaging Sample Search...  

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

gamma-ray imaging Search Powered by Explorit Topic List Advanced Search Sample search results for: atmospheric gamma-ray imaging Page: << < 1 2 3 4 5 > >> 1 Ivan De Mitri VHE Gamma...

434

The Search for Muon Neutrinos from Northern Hemisphere Gamma-Ray Bursts with AMANDA  

E-Print Network (OSTI)

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

Achterberg, A.; IceCube Collaboration

2008-01-01T23:59:59.000Z

435

Search for muon neutrinos from Gamma-Ray Bursts with the IceCube neutrino telescope  

E-Print Network (OSTI)

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

Abbasi, R.

2010-01-01T23:59:59.000Z

436

Long gamma-ray bursts and core-collapse supernovae have different environments  

E-Print Network (OSTI)

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:

2006-01-01T23:59:59.000Z

437

Effect of Steam Sterilization and Gamma Irradiation of Peat on Quality of Rhizobium Inoculants  

Science Journals Connector (OSTI)

...and Industrial Microbiology Effect of Steam Sterilization and Gamma Irradiation of...Inoculants for M. sativa manufactured with steam-sterilized peat were similar in quality...higher gamma irradiation dosage. Effect of steam sterilization and gamma irradiation of...

Barend W. Strijdom; Henri Jansen van Rensburg

1981-06-01T23:59:59.000Z

438

Physics of Gamma-ray Bursts and Multi-messenger Signals from Double Neutron Star Mergers.  

E-Print Network (OSTI)

??My dissertation includes two parts: Physics of Gamma-Ray Bursts (GRBs): Gamma-ray bursts are multi-wavelength transients, with both prompt gamma-ray emission and late time afterglow emission… (more)

Gao, He

2014-01-01T23:59:59.000Z

439

Astrophysical explosions: from solar flares to cosmic gamma-ray bursts  

Science Journals Connector (OSTI)

...from solar flares to cosmic gamma-ray bursts J. Craig Wheeler * * wheel...collapse supernovae and cosmic gamma-ray bursts, each representing a different...black holes|supernovae|gamma-ray bursts|deflagration|detonation...

2012-01-01T23:59:59.000Z

440

A method for calculation of radiation quantities at all points in gamma radiation calibration fields  

Science Journals Connector (OSTI)

......Chi-square test in a gamma radiation calibration field was...dimensions) in a gamma radiation calibration field can...be used in dosimetry software of gamma radiation calibration fields...2000) Vienna: IAEA. Safety Reports Series, No......

S. M. Hosseini-Pooya; M. Khoshnoodi; A. Ansarinejad; F. Torkzadeh; M. Jafarizadeh

2008-03-01T23:59:59.000Z

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


441

Search for muon neutrinos from Gamma-Ray Bursts with the IceCube neutrino telescope  

E-Print Network (OSTI)

of California. Search for muon neutrinos from Gamma-RaySearch for muon neutrinos from Gamma-Ray Bursts with theof searches for high-energy muon neutrinos from 41 gamma-

Abbasi, R.

2010-01-01T23:59:59.000Z

442

Terrestrial gamma ray flash production by active lightning leader channels  

E-Print Network (OSTI)

Terrestrial gamma ray flash production by active lightning leader channels B. E. Carlson,1 N. G 28 October 2010. [1] The production of terrestrial gamma ray flashes (TGFs) requires a seed energetic electron source and a strong electric field. Lightning leaders naturally provide seed electrons by cold

Bergen, Universitetet i

443

Probing WWgamma coupling through e gamma --> nu W at ILC  

E-Print Network (OSTI)

The anomalous WWgamma coupling is probed through e gamma--> nu W at the ILC. With a spectacular single lepton final state, this process is well suited to study the above coupling. Within the narrow-width approximation, a semi-analytical study of the secondary lepton energy-angle double distribution is performed. Cross section measurements can probe delta-kappa-gamma to about +/- 0.004 for a luminosity of 100 /fb at 500 GeV center of mass energy with unpolarised electron beam. The limits derivable on lambda-gamma are comparatively more relaxed. These limits can be improved significantly by considering the angle and energy distributions of the final state muon. More importantly, the angular distributions at fixed energy values, and energy distribution at fixed angles present very interesting possibility of distinguishing the case of lambda-gamma=0, lambda-gamma 0.

Kumar, Satendra

2015-01-01T23:59:59.000Z

444

Polarization mesurements of gamma ray bursts and axion like particles  

E-Print Network (OSTI)

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

Andre Rubbia; Alexander Sakharov

2008-09-03T23:59:59.000Z

445

The GAMMA-400 space observatory: status and perspectives  

E-Print Network (OSTI)

The present design of the new space observatory GAMMA-400 is presented in this paper. The instrument has been designed for the optimal detection of gamma rays in a broad energy range (from ~100 MeV up to 3 TeV), with excellent angular and energy resolution. The observatory will also allow precise and high statistic studies of the electron component in the cosmic rays up to the multi TeV region, as well as protons and nuclei spectra up to the knee region. The GAMMA-400 observatory will allow to address a broad range of science topics, like search for signatures of dark matter, studies of Galactic and extragalactic gamma-ray sources, Galactic and extragalactic diffuse emission, gamma-ray bursts and charged cosmic rays acceleration and diffusion mechanism up to the knee.

Galper, A M; 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; Boyarchuk, K A; 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; Leonov, A A; 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

2014-01-01T23:59:59.000Z

446

EFFECTS OF GAMMA IRRADIATION ON EPDM ELASTOMERS  

SciTech Connect

Two formulations of EPDM elastomer, one substituting a UV stabilizer for the normal antioxidant in this polymer, and the other the normal formulation, were synthesized and samples of each were exposed to gamma irradiation in initially pure deuterium gas to compare their radiation stability. Stainless steel containers having rupture disks were designed for this task. After 130 MRad dose of cobalt-60 radiation in the SRNL Gamma Irradiation Facility, a significant amount of gas was created by radiolysis; however the composition indicated by mass spectroscopy indicated an unexpected increase in the total amount deuterium in both formulations. The irradiated samples retained their ductility in a bend test. No change of sample weight, dimensions, or density was observed. No change of the glass transition temperature as measured by dynamic mechanical analysis was observed, and most of the other dynamic mechanical properties remained unchanged. There appeared to be an increase in the storage modulus of the irradiated samples containing the UV stabilizer above the glass transition, which may indicate hardening of the material by radiation damage. Polymeric materials become damaged by exposure over time to ionizing radiation. Despite the limited lifetime, polymers have unique engineering material properties and polymers continue to be used in tritium handling systems. In tritium handling systems, polymers are employed mainly in joining applications such as valve sealing surfaces (eg. Stem tips, valve packing, and O-rings). Because of the continued need to employ polymers in tritium systems, over the past several years, programs at the Savannah River National Laboratory have been studying the effect of tritium on various polymers of interest. In these studies, samples of materials of interest to the SRS Tritium Facilities (ultra-high molecular weight polyethylene (UHMW-PE), polytetrafluoroethylene (PTFE, Teflon{reg_sign}), Vespel{reg_sign} polyimide, and the elastomer ethylene propylene diene monomer (EPDM)) have been exposed in closed containers to tritium gas initially at 1 atmosphere pressure. These studies have demonstrated the degradation of properties when exposed to tritium gas. Also, the radiolytic production of significant amounts of hydrogen has been observed for UHMW-PE and EPDM. The study documented in this report exposes two similar formulations of EPDM elastomer to gamma irradiation in a closed container backfilled with deuterium. Deuterium is chemically identical to protium and tritium, but allows the identification of protium that is radiolytically produced from the samples. The goal of this program is to compare and contrast the response of EPDM exposure to two different types of ionizing radiation in a similar chemical environment.

Clark, E.

2011-09-22T23:59:59.000Z

447

Existence of two sets of kinetic parameters in the correlation of the hydrogen electrode reaction  

SciTech Connect

It has been demonstrated that the dependence of the current density on overpotential for the hydrogen electrode reaction described through the Volmer-Heyrovsky-Tafel mechanism can be correlated by two different sets of the kinetic parameters. Such sets lead to two different dependencies of the surface coverage on overpotential, while a unique dependence of the corresponding pseudocapacitance of adsorption is obtained. The expressions that relate both sets of kinetic parameters have been established and analyzed for the simultaneous occurrence of the three steps and for the different kinetic routes.

Chialvo, M.R.G. de; Chialvo, A.C.

2000-05-01T23:59:59.000Z

448

THE INTERPLANETARY NETWORK SUPPLEMENT TO THE FERMI GBM CATALOG OF COSMIC GAMMA-RAY BURSTS  

SciTech Connect

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.

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

449

MODELING PHASE-ALIGNED GAMMA-RAY AND RADIO MILLISECOND PULSAR LIGHT CURVES  

SciTech Connect

Since the discovery of the first eight gamma-ray millisecond pulsars (MSPs) by the Fermi Large Area Telescope, this population has been steadily expanding. Four of the more recent detections, PSR J0034-0534, PSR J1939+2134 (B1937+21; the first MSP ever discovered), PSR J1959+2048 (B1957+20; the first discovery of a black widow system), and PSR J2214+3000, exhibit a phenomenon not present in the original discoveries: nearly phase-aligned radio and gamma-ray light curves (LCs). To account for the phase alignment, we explore models where both the radio and gamma-ray emission originate either in the outer magnetosphere near the light cylinder or near the polar caps. Using a Markov Chain Monte Carlo technique to search for best-fit model parameters, we obtain reasonable LC fits for the first three of these MSPs in the context of 'altitude-limited' outer gap (alOG) and two-pole caustic (alTPC) geometries (for both gamma-ray and radio emission). These models differ from the standard outer gap (OG)/two-pole caustic (TPC) models in two respects: the radio emission originates in caustics at relatively high altitudes compared to the usual conal radio beams, and we allow both the minimum and maximum altitudes of the gamma-ray and radio emission regions to vary within a limited range (excluding the minimum gamma-ray altitude of the alTPC model, which is kept constant at the stellar radius, and that of the alOG model, which is set to the position-dependent null charge surface altitude). Alternatively, phase-aligned solutions also exist for emission originating near the stellar surface in a slot gap scenario ('low-altitude slot gap' (laSG) models). We find that the alTPC models provide slightly better LC fits than the alOG models, and both of these give better fits than the laSG models (for the limited range of parameters considered in the case of the laSG models). Thus, our fits imply that the phase-aligned LCs are likely of caustic origin, produced in the outer magnetosphere, and that the radio emission for these pulsars may come from close to the light cylinder. In addition, we were able to constrain the minimum and maximum emission altitudes with typical uncertainties of {approx}30% of the light cylinder radius. Our results therefore describe a third gamma-ray MSP subclass, in addition to the two previously found by Venter et al.: those with LCs fit by standard OG/TPC models and those with LCs fit by pair-starved polar cap models.

Venter, C. [Centre for Space Research, North-West University, Potchefstroom Campus, Potchefstroom 2520 (South Africa); Johnson, T. J.; Harding, A. K. [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

2012-01-01T23:59:59.000Z

450

Folk Theorems on the Correspondence between State-Based and Event-Based Systems  

E-Print Network (OSTI)

Kripke Structures and Labelled Transition Systems are the two most prominent semantic models used in concurrency theory. Both models are commonly believed to be equi-expressive. One can find many ad-hoc embeddings of one of these models into the other. We build upon the seminal work of De Nicola and Vaandrager that firmly established the correspondence between stuttering equivalence in Kripke Structures and divergence-sensitive branching bisimulation in Labelled Transition Systems. We show that their embeddings can also be used for a range of other equivalences of interest, such as strong bisimilarity, simulation equivalence, and trace equivalence. Furthermore, we extend the results by De Nicola and Vaandrager by showing that there are additional translations that allow one to use minimisation techniques in one semantic domain to obtain minimal representatives in the other semantic domain for these equivalences.

Reniers, M A

2010-01-01T23:59:59.000Z

451

Note on Gauge Theories on M/G and the AdS/CFT Correspondence  

E-Print Network (OSTI)

It is well known that a weakly coupled U(N) gauge theory on a torus with sides of length L has extra light states with energies of order 1/NL. We show that a similar result holds for gauge theories on M/G where M is any compact Riemannian manifold and G is any freely acting discrete isometry group. As in the toroidal case, this is achieved by adding a suitable nontrivial flat connection. As one application, we consider the AdS/CFT correspondence on spacetimes asymptotic to AdS_5/G. By considering finite size effects at nonzero temperature, we show that consistency requires these extra light states of the gauge theory on S^3/G.

Gary T. Horowitz; Ted Jacobson

2002-01-02T23:59:59.000Z

452

Adjoint Lattice Boltzmann Equation for Parameter Identification  

E-Print Network (OSTI)

Adjoint Lattice Boltzmann Equation for Parameter Identification M.M. Tekitek a,b , M. Bouzidi c , F@asci.fr, francois.dubois@math.u-psud.fr, pierre.lal@free.fr 26 January 2005 Abstract. The Lattice Boltzmann to the Lattice Boltzmann Equation to get expressions for the derivatives of the cost function vs. parameters

Boyer, Edmond

453

PARAMETER ESTIMATION IN PETROLEUM AND GROUNDWATER MODELING  

E-Print Network (OSTI)

on grand challenge problems. In today's petroleum industry, reservoir simulators are routinely usedPARAMETER ESTIMATION IN PETROLEUM AND GROUNDWATER MODELING R.E. Ewing, M.S. Pilant, J.G. Wade in the model, the numerical discretization used, and the solution algorithms employed. Parameter identification

Ewing, Richard E.

454

Transport and noise properties of Si nanowire channels with different lengths before and after gamma radiation treatment  

SciTech Connect

The transport properties of Si nanowire (NW) structures fabricated on the basis of silicon on insulator (SOI) wafers were studied using noise spectroscopy before and after treatment with small doses of gamma radiation. The total resistance obtained from the I-V characteristics of Si NW structures scaled perfectly with length. Normalized flicker noise demonstrated 1/L{sup 2} dependence, which is a characteristic of dominant noise contribution from near-contact regions. The behavior changed to 1/L dependence after a small dose (1×10{sup 4} Gy) of gamma radiation treatment. Comparison of the random telegraph signal (RTS) noise parameters in the samples with small lengths before and after the treatment revealed a decrease in RTS amplitude and a shift to a lower frequency range after gamma irradiation. These results confirmed that the main changes in the samples were related to strain relaxation near-contact regions. In addition, such treatment resulted in a considerable decrease in the scattering data of device parameters.

Li, Jing; Vitusevich, Svetlana; Pud, Sergii; Sydoruk, Viktor; Offenhäusser, Andreas [Peter Grünberg Institute, Forschungszentrum Jülich (Germany); Petrychuk, Mykhailo [Taras Shevchenko National University, Kiev (Ukraine); Danilchenko, Boris [Institute of Physics, NASU, Kiev (Ukraine)

2013-12-04T23:59:59.000Z

455

DISCOVERY OF A NEW TeV GAMMA-RAY SOURCE: VER J0521+211  

SciTech Connect

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.

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

456

A novel paradigm for short gamma-ray bursts with extended X-ray emission  

E-Print Network (OSTI)

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.

Luciano Rezzolla; Pawan Kumar

2015-01-21T23:59:59.000Z

457

Deep Broadband Observations of the Distant Gamma-ray Blazar PKS 1424+240  

E-Print Network (OSTI)

We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of $z\\ge0.6035$, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hours of VERITAS observations from three years, a multiwavelength light curve and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1$\\pm0.3$)$\\times10^{-7}$ ph m$^{-2}$s$^{-1}$ above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02$\\pm0.08$)$\\times10^{-7}$ ph m$^{-2}$s$^{-1}$ above 120 GeV. The measured differential very high energy (VHE; $E\\ge100$ GeV) spectral indices are $\\Gamma=$3.8$\\pm$0.3, 4.3$\\pm$0.6 and 4.5$\\pm$0.2 in 2009, 2011 and 2013, respectively. No significant spectral change...

Archambault, S; Behera, B; Beilicke, M; Benbow, W; Berger, K; Bird, R; Biteau, J; Bugaev, V; Byrum, K; Cardenzana, J V; Cerruti, M; Chen, X; Ciupik, L; Connolly, M P; Cui, W; Dumm, J; Errando, M; Falcone, A; Federici, S; Feng, Q; Finley, J P; Fleischhack, H; Fortson, L; Furniss, A; Galante, N; Gillanders, G H; Griffin, S; Griffiths, S T; Grube, J; Gyuk, G; Hanna, D; Holder, J; Hughes, G; Humensky, T B; Johnson, C A; Kaaret, P; Kertzman, M; Khassen, Y; Kieda, D; Krawczynski, H; Krennrich, F; Kumar, S; Lang, M J; Madhavan, A S; Maier, G; McCann, A; Meagher, K; Moriarty, P; Mukherjee, R; Nieto, D; de Bhroithe, A O'Faolain; Ong, R A; Otte, A N; Park, N; Pohl, M; Popkow, A; Prokoph, H; Quinn, J; Ragan, K; Rajotte, J; Reyes, L C; Reynolds, P T; Richards, G T; Roache, E; Sembroski, G H; Shahinyan, K; Staszak, D; Telezhinsky, I; Tucci, J V; Tyler, J; Varlotta, A; Vassiliev, V V; Vincent, S; Wakely, S P; Weinstein, A; Welsing, R; Wilhelm, A; Williams, D A; Ackermann, M; Ajello, M; Albert, A; Baldini, L; Bastieri, D; Bellazzini, R; Bissaldi, E; Bregeon, J; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Cavazzuti, E; Charles, E; Chiang, J; Ciprini, S; Claus, R; Cutini, S; D'Ammando, F; de Angelis, A; de Palma, F; Dermer, C D; Digel, S W; Di Venere, L; Drell, P S; Favuzzi, C; Franckowiak, A; Fusco, P; Gargano, F; Gasparrini, D; Giglietto, N; Giordano, F; Giroletti, M; Grenier, I A; Guiriec, S; Jogler, T; Kuss, M; Larsson, S; Latronico, L; Longo, F; Loparco, F; Lubrano, P; Madejski, G M; Mayer, M; Mazziotta, M N; Michelson, P F; Mizuno, T; Monzani, M E; Morselli, A; Murgia, S; Nuss, E; Ohsugi, T; Ormes, J F; Perkins, J S; Piron, F; Pivato, G; Raino, S; Razzano, M; Reimer, A; Reimer, O; Ritz, S; Schaal, M; Sgro, C; Siskind, E J; Spinelli, P; Takahashi, H; Tibaldo, L; Tinivella, M; Troja, E; Vianello, G; Werner, M; Wood, M

2014-01-01T23:59:59.000Z

458

A new approach in the detection of weak {\\gamma}-ray peak of the radioactive waste in tomography {\\gamma} scanning  

E-Print Network (OSTI)

We demonstrate a new approach to efficiently detect weak {\\gamma}-ray peak of the radioactive waste in tomographic {\\gamma} scanning (TGS). In the TGS measurement, {\\gamma}-ray peak identification is usually difficult due to the short measurement time that results in a lower {\\gamma}-ray energy produced by the decay. Consequently, the resulting significant scattering in the low-energy side leads to strong statistical fluctuations and low detection efficiency that overwhelm the {\\gamma}-ray peak. Here, we propose the use of shift invariance wavelet algorithm for low-energy part of the spectrum for weak {\\gamma}-ray peak smoothing. The proposed algorithm not only overcomes the pseudo-Gibbs in the high-resolution {\\gamma}-ray spectrum de-noising by the traditional wavelet transform, but also keeps quality of the weak {\\gamma}-ray characteristic peak as well. Our new approach shows a significantly improved performance of the figure of merit (FOM) together with lower limit of quantitation (LLOQ) compared with the ...

Jinzha, Zhang

2014-01-01T23:59:59.000Z

459

E-Print Network 3.0 - advanced gamma ray Sample Search Results  

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

gamma ray Search Powered by Explorit Topic List Advanced Search Sample search results for: advanced gamma ray Page: << < 1 2 3 4 5 > >> 1 Memory Referencing Behavior in...

460

Magnetic Structures in Gamma-Ray Burst Jets Probed by Gamma-Ray Polarization  

E-Print Network (OSTI)

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.

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

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461

MAGNETIC STRUCTURES IN GAMMA-RAY BURST JETS PROBED BY GAMMA-RAY POLARIZATION  

SciTech Connect

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.

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

462

Muon Detection of TeV Gamma Rays from Gamma-Ray Bursts  

Science Journals Connector (OSTI)

Because of the limited size of the satellite-borne instruments, it has not been possible to observe the flux of gamma-ray bursts (GRBs) beyond GeV energy. We here show that it is possible to detect the GRB radiation of TeV energy and above by detecting the muon secondaries produced when the gamma rays shower in Earth's atmosphere. Observation is made possible by the recent commissioning of underground detectors (AMANDA, the Lake Baikal detector, and MILAGRO), which combine a low muon threshold of a few hundred GeV or less, with a large effective area of 103 m2 or more. Observations will not only provide new insights in the origin and characteristics of GRB, but they also will provide quantitative information on the diffuse infrared background.

J. Alvarez-Muñiz; F. Halzen

1999-01-01T23:59:59.000Z

463

Gamma-gamma directional correlation measurements in 84Kr following thermal neutron capture by natural krypton  

Science Journals Connector (OSTI)

Directional correlations of gamma-ray cascades in 84Kr have been measured following thermal neutron capture by a pressurised natural krypton gas target. Gamma-ray singles spectra were measured up to 5.5 MeV and the correlation data were obtained for the energy range 0.2-2.5 MeV. A decay scheme was developed on the basis of coincidence measurements. The data allow spin-parity assignments to be made to most levels lying below 3.5 MeV and multipole mixing ratios to be evaluated for the more intense transitions. The results are fitted to the SU(5) limit of the IBM-1 and to the IBM-2 and are also compared with the predictions of the dynamic deformation model which indicates that 84Kr is the only krypton isotope with a prolate equilibrium shape. A possible mixed symmetry 2+ state at 2.623 MeV is identified.

S A Hamada; W D Hamilton; F Hoyler

1987-01-01T23:59:59.000Z

464

Biases on cosmological parameter estimators from galaxy cluster number counts  

E-Print Network (OSTI)

Sunyaev-Zel'dovich (SZ) surveys are promising probes of cosmology - in particular for Dark Energy (DE) -, given their ability to find distant clusters and provide estimates for their mass. However, current SZ catalogs contain tens to hundreds of objects and maximum likelihood estimators may present biases for such sample sizes. In this work we use the Monte Carlo approach to determine the presence of bias on cosmological parameter estimators from cluster abundance as a function of the area and depth of the survey, and the number of cosmological parameters fitted. Assuming perfect knowledge of mass and redshift some estimators have non-negligible biases. For example, the bias of $\\sigma_8$ corresponds to about $40%$ of its statistical error bar when fitted together with $\\Omega_c$ and $w_0$. Including a SZ mass-observable relation decreases the relevance of the bias, for the typical sizes of current surveys. The biases become negligible when combining the SZ data with other cosmological probes. However, we show that the biases from SZ estimators do not go away with increasing sample sizes and they may become the dominant source of error for an all sky survey at the South Pole Telescope (SPT) sensitivity. The results of this work validate the use of the current maximum likelihood methods for present SZ surveys, but highlight the need for further studies for upcoming experiments. [abridged

M. Penna-Lima; M. Makler; C. A. Wuensche

2013-12-16T23:59:59.000Z

465

Gamma Solar Corporation | Open Energy Information  

Open Energy Info (EERE)

Solar Corporation Solar Corporation Jump to: navigation, search Name Gamma Solar Corporation Place Weston, Florida Zip 33326 Product Florida-based firm developing a technology for bifacial and monofacial crystalline silicon cells and modules. Coordinates 44.708658°, -105.371181° Loading map... {"minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom":14,"types":["ROADMAP","SATELLITE","HYBRID","TERRAIN"],"geoservice":"google","maxzoom":false,"width":"600px","height":"350px","centre":false,"title":"","label":"","icon":"","visitedicon":"","lines":[],"polygons":[],"circles":[],"rectangles":[],"copycoords":false,"static":false,"wmsoverlay":"","layers":[],"controls":["pan","zoom","type","scale","streetview"],"zoomstyle":"DEFAULT","typestyle":"DEFAULT","autoinfowindows":false,"kml":[],"gkml":[],"fusiontables":[],"resizable":false,"tilt":0,"kmlrezoom":false,"poi":true,"imageoverlays":[],"markercluster":false,"searchmarkers":"","locations":[{"text":"","title":"","link":null,"lat":44.708658,"lon":-105.371181,"alt":0,"address":"","icon":"","group":"","inlineLabel":"","visitedicon":""}]}

466

Gamma-ray blind beta particle probe  

DOE Patents (OSTI)

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.

Weisenberger, Andrew G. (Grafton, VA)

2001-01-01T23:59:59.000Z

467

Constraining Lorentz violations with Gamma Ray Bursts  

E-Print Network (OSTI)

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.

Maria Rodriguez Martinez; Tsvi Piran

2006-05-17T23:59:59.000Z

468

Lorentz invariance violation with gamma rays  

E-Print Network (OSTI)

The assumption of Lorentz invariance is one of the founding principles of Modern Physics and violation of it would have profound implications to our understanding of the universe. For instance, certain theories attempting a unified theory of quantum gravity predict there could be an effective refractive index of the vacuum; the introduction of an energy dependent dispersion to photons could in turn lead to an observable Lorentz invariance violation signature. Whilst a very small effect on local scales the effect will be cumulative, and so for very high energy particles that travel very large distances the difference in arrival times could become sufficiently large to be detectable. This proceedings will look at testing for such Lorentz invariance violation (LIV) signatures in the astronomical lightcurves of gamma-ray emitting objects, with particular notice being given to the prospects for LIV testing with, the next generation observatory, the Cherenkov Telescope Array.

Daniel, Michael

2015-01-01T23:59:59.000Z

469

Radioactivity concentrations in soil and vegetables from the northern Jordan Rift Valley and the corresponding dose estimates  

Science Journals Connector (OSTI)

......concept as applied to natural uranium. Health Phys (1985) 48:494-500...soil-to-plant transfer factors for uranium and thorium isotopes and 226Ra...Zunic Z. S. Determination of depleted uranium in environmental samples by gamma-spectroscopic......

Anas M. Ababneh; Maisoun S. Masa'deh; Zaid Q. Ababneh; Mufeed A. Awawdeh; Abdalmajeid M. Alyassin

2009-02-01T23:59:59.000Z

470

High Energy Gamma-Ray Emission from Gamma-Ray Bursts - Before GLAST  

SciTech Connect

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.

Fan, Yi-Zhong; Piran, Tsvi

2011-11-29T23:59:59.000Z

471

On The Origin Of High Energy Correlations in Gamma-ray Bursts  

SciTech Connect

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.

Kocevski, Daniel

2012-04-03T23:59:59.000Z

472

ON THE ORIGIN OF HIGH-ENERGY CORRELATIONS IN GAMMA-RAY BURSTS  

SciTech Connect

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.

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

473

MFV Reductions of MSSM Parameter Space  

E-Print Network (OSTI)

The 100+ free parameters of the minimal supersymmetric standard model (MSSM) make it computationally difficult to compare systematically with data, motivating the study of specific parameter reductions such as the cMSSM and pMSSM. Here we instead study the reductions of parameter space implied by using minimal flavour violation (MFV) to organise the R-parity conserving MSSM, with a view towards systematically building in constraints on flavour-violating physics. Within this framework the space of parameters is reduced by expanding soft supersymmetry-breaking terms in powers of the Cabibbo angle, leading to a 24-, 30- or 42-parameter framework (which we call MSSM-24, MSSM-30, and MSSM-42 respectively), depending on the order kept in the expansion. We provide a Bayesian global fit to data of the MSSM-30 parameter set to show that this is manageable with current tools. We compare the MFV reductions to the 19-parameter pMSSM choice and show that the pMSSM is not contained as a subset. The MSSM-30 analysis favours a relatively lighter TeV-scale pseudoscalar Higgs boson and $\\tan \\beta \\sim 10$ with multi-TeV sparticles.

S. S. AbdusSalam; C. P. Burgess; F. Quevedo

2015-02-09T23:59:59.000Z

474

Investment casting of {gamma}-TiAl-based alloys: Microstructure and data base for gas turbine applications  

SciTech Connect

Investment casting is regarded as an economic processing technology for the production of {gamma}-TiAl based components for gas turbine applications. Near net-shape parts can be cast such that they are free from pores and flaws after adequate `HIP`ping. The inhomogeneous cast microstructure which results from locally varying cooling rates (e.g. in the root and foil of a blade), however, is often retained even after heat-treatments necessary to achieve a balance of properties for a given application. Appropriate modifications of the alloy chemistry may lead to an improved microstructural homogeneity in the cast parts. Data bases of properties (tensile properties, creep, fatigue and rupture strength, fracture and impact toughness, oxidation and corrosion resistance) which are relevant for potential gas turbine applications have been assessed for different cast {gamma}-TiAl alloys with different microstructures. These are compared with corresponding properties of nickel-based and iron-based superalloys {gamma}-TiAl is competing with for substitution.

Wagner, R.; Appel, F.; Dogan, B. [GKSS Research Center, Geesthacht (Germany). Inst. for Materials Research] [and others

1995-12-31T23:59:59.000Z

475

Additional resonant contribution to the potential model for the 12C(alpha,gamma)16O reaction  

E-Print Network (OSTI)

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.

M. Katsuma

2014-04-15T23:59:59.000Z

476

Gamma-ray Astronomy: Implications for Fundamental Physics  

E-Print Network (OSTI)

Gamma-ray Astronomy studies cosmic accelerators through their electromagnetic radiation in the energy range between ~100 MeV and ~100 TeV. The present most sensitive observations in this energy band are performed, from space, by the Large Area Telescope onboard the Fermi satellite and, from Earth, by the Imaging Air Cherenkov Telescopes MAGIC, H.E.S.S. and VERITAS. These instruments have revolutionized the field of Gamma-ray Astronomy, discovering different populations of gamma-ray emitters and studying in detail the non-thermal astrophysical processes producing this high-energy radiation. The scientific objectives of these observatories include also questions of fundamental physics. With gamma-ray instruments we study the origin of Galactic cosmic rays, testing the hypothesis or whether they are mainly produced in supernova explosions. Also, we obtain the most sensitive measurement of the cosmic electron-positron spectrum between 20 GeV and 5 TeV. By observing the gamma-ray emission from sources at cosmological distances, we learn about the intensity and evolution of the extragalactic background light, and perform tests of Lorentz Invariance. Moreover, we can search for dark matter by looking for gamma-ray signals produced by its annihilation or decay in over-density sites. In this paper, we review the most recent results produced with the current generation of gamma-ray instruments in these fields of research.

Javier Rico

2011-11-28T23:59:59.000Z

477

Investigating the Correspondence Between Transcriptomic and Proteomic Expression Profiles Using Coupled Cluster Models.  

SciTech Connect

Modern transcriptomics and proteomics enable us to survey the expression of RNAs and proteins at large scales. While these data are usually generated and analysed separately, there is an increasing interest in comparing and co-analysing transcriptome and proteome expression data. A major open question is whether transcriptome and proteome expression is linked and how it is coordinated. Results: Here we have developed a probabilistic clustering model that permits analysis of the links between transcriptomic and proteomic profiles in a sensible and flexible manner. Our coupled mixture model defines a prior probability distribution over the component to which a protein profile should be assigned conditioned on which component the associated mRNA profile belongs to. By providing probabilistic assignments this approach sits between the two extremes of concatenating the data on the assumption that mRNA and protein clusters would have a one-to-one relationship, and independent clustering where the mRNA profile provides no information on the protein profile and vice-versa. We apply this approach to a large dataset of quantitative transcriptomic and proteomic expression data obtained from a human breast epithelial cell line (HMEC) stimulated by epidermal growth factor (EGF) over a series of timepoints corresponding to one cell cycle. The results reveal a complex relationship between transcriptome and proteome with most mRNA clusters linked to at least two protein clusters, and vice versa. A more detailed analysis incorporating information on gene function from the gene ontology database shows that a high correlation of mRNA and protein expression is limited to the components of some molecular machines, such as the ribosome, cell adhesion complexes and the TCP-1 chaperonin involved in protein folding. Conclusions: The dynamic regulation of the transcriptome and proteome in mammalian cells in response to an acute mitogenic stimulus appears largely independent with very little correspondence between mRNA and protein expression. The exceptions involve a few selected multi-protein complexes that require the stoichiometric expression of components for correct function. This finding has wide ramifications regarding the understanding of gene and protein expression including its control and evolution. It also show