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Physics of supernovae

Description: Presupernova models of massive stars are presented and their explosion by ''delayed neutrino transport'' examined. A new form of long duration Type II supernova model is also explored based upon repeated encounter with the electron-positron pair instability in stars heavier than about 60 Msub solar. Carbon deflagration in white dwarfs is discussed as the probable explanation of Type I supernovae and special attention is paid to the physical processes whereby a nuclear flame propagates through d… more
Date: December 13, 1985
Creator: Woosley, S. E. & Weaver, T. A.
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Partner: UNT Libraries Government Documents Department
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Bragg Crystal Polarimeter for the Spectrum-X-Gamma Mission

Description: We are designing a Bragg crystal polarimeter for the focal plane of the SODART telescope on the Spectrum-X-Gamma mission. A mosaic graphite crystal will be oriented at 45{degree} to the optic axis of the telescope, thereby preferentially reflecting those x-rays which satisfy the Bragg condition and have electric vectors that are perpendicular to the plane defined by the incident and reflected photons. The reflected x-rays will be detected by an imaging proportional counter with the image provid… more
Date: August 13, 1990
Creator: Holley, J.; Silver, E.; Ziock, K.P. (Lawrence Livermore National Lab., CA (USA)); Novick, R.; Kaaret, P. (Columbia Univ., New York, NY (USA). Columbia Astrophysics Lab.); Weisskopf, M. et al.
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Partner: UNT Libraries Government Documents Department
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Dual-phase argon ionization detector for measurement of coherent elastic neutrino scattering and medium-energy nuclear recoils

Description: We propose to build and deploy a 10-kg dual-phase argon ionization detector for the detection of coherent neutrino-nucleus scattering, which is described by the reaction; (V) + (Z,N) {yields} (v) + (Z,N). Our group would be the first to make this measurement. Its detection would validate (or refute) central tenets of the Standard Model. The existence of this process is also relevant to astrophysics, where coherent neutrino scattering is assumed to impede energy transport within neutron stars. W… more
Date: September 13, 2006
Creator: Winant, C D; Bernstein, A; Hagmann, C; Madden, N & Stoeffl, W
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Partner: UNT Libraries Government Documents Department
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X-ray Induced Pinhole Closure in Point Projection X-ray Radiography

Description: In pinhole-assisted point-projection x-ray radiography (or ''backlighting''), pinholes are placed between the sample of interest and an x-ray source (or ''backlighter'') to effectively limit the source size and hence improve the spatial resolution of the system. Pinholes are generally placed close to such x-ray backlighters to increase the field-of-view, leading to possible vaporization and pinhole closure due to x-ray driven ablation, thereby potentially limiting the usefulness of this method.… more
Date: January 13, 2006
Creator: Bullock, A. B.; Landen, O. L.; Blue, B. E.; Edwards, J. & Bradley, D. K.
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Partner: UNT Libraries Government Documents Department
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Report on the Instrument Development Workshop for Biological Imaging Experiments at LCLS

Description: The Linac Coherent Light Source (LCLS) will launch a new era in X-ray science by providing 200 fs pulses of X rays with a peak brightness up to 10 orders of magnitude greater than current sources. One of the most exciting and far-reaching experiments that this new source will enable is single-particle diffraction imaging, whereby atomic-resolution structure of biological macromolecules, complexes, or viruses could be obtained without the need for crystallization. Time-resolved structures and dy… more
Date: August 13, 2004
Creator: Chapman, H; Hajdu, J & Hodgson, K
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Partner: UNT Libraries Government Documents Department
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Relativistic Electron Beam Transport and Characteristics in Solid Density Plasmas

Description: The transport of intense relativistic beams in solid density plasma presently is actively being studied in laser laboratories around the world. The correct understanding of the transport enables further application of fast laser driven electrons to a host of interesting uses. Advanced x-ray sources, proton and ion beam generation and plasma heating in fast ignitor fusion all are owed their eventual utility to this transport. We report on measurements of relativistic transport over the whole of … more
Date: August 13, 2003
Creator: Snavely, R. A.; King, J.; Freeman, R. R.; Hatchett, S.; Key, M. H.; Koch, J. et al.
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Partner: UNT Libraries Government Documents Department
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Simulations of Inertial Confinement Fusion Driven by a Novel Synchrotron Radiation-Based X-Ray Igniter

Description: The advantages and challenges of using a powerful x-ray source for the fast ignition of compressed Inertial Confinement Fusion (ICF) targets have been considered. The requirements for such a source together with the optics to focus the x-rays onto compressed DT cores lead to a conceptual design based on Energy Recovery Linacs (ERLs) and long wigglers to produce x-ray pulses with the appropriate phase space properties. A comparative assessment of the parameters of the igniter system indicates th… more
Date: January 13, 2004
Creator: Shlyaptsev, V & Tatchyn, R
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Partner: UNT Libraries Government Documents Department
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The Filamentary Large Scale Structure around the z=2.16 Radio Galaxy PKS 1138-262

Description: PKS 1138-262 is a massive radio galaxy at z = 2.16 surrounded by overdensities of Ly{alpha} emitters, H{alpha} emitters, EROs and X-ray emitters. Numerous lines of evidence exist that it is located in a forming cluster. We report on Keck spectroscopy of candidate members of this protocluster, including nine of the 18 X-ray sources detected by Pentericci et al. (2002) in this field. Two of these X-ray sources (not counting PKS 1138-262 itself) were previously confirmed to be members of the proto… more
Date: April 13, 2005
Creator: Croft, S.; Kurk, J.; van Breugel, W.; Stanford, S. A.; de Vries, W.; Pentericci, L. et al.
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Partner: UNT Libraries Government Documents Department
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The Z accelerator as a source of > 100 kJ of x-rays above 4.8 keV

Description: Recent K-shell scaling experiments on the 20 MA Z accelerator at Sandia National Laboratories have shown that large diameter (40 and 55 mm) arrays can be imploded with 80 to 210 wires of titanium or stainless steel. These implosions have produced up to 150 kJ of > 4.5 keV x-rays and 65 kJ of > 6.0 keV x-rays in 7 to 18 ns FWHM pulses. This is a major advance in plasma radiation source (PRS) capability since there is presently limited test capability above 3 keV. In fact, Z produces more > 4.5 k… more
Date: April 13, 1998
Creator: Deeney, C.; Coverdale, C. A. & Spielman, R. B.
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Partner: UNT Libraries Government Documents Department
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Scaling and optimization of the radiation temperature in dynamic hohlraums

Description: The authors have constructed a quasi-analytic model of the dynamic hohlraum. Solutions only require a numerical root solve, which can be done very quickly. Results of the model are compared to both experiments and full numerical simulations with good agreement. The computational simplicity of the model allows one to find the behavior of the hohlraum temperature as a function the various parameters of the system and thus find optimum parameters as a function of the driving current. The model is … more
Date: April 13, 2000
Creator: SLUTZ,STEPHEN A.; DOUGLAS,MELISSA R.; LASH,JOEL S.; VESEY,ROGER A.; CHANDLER,GORDON A.; NASH,THOMAS J. et al.
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Partner: UNT Libraries Government Documents Department
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