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in subjects: "Energy Dependence"  
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Experimental evidence for the reducibility of multifragment emission probabilities

Description: Multifragmentation has been studied for {sup 36}Ar-induced reactions on a {sup 197}Au target at E/A = 80 and 110 MeV and for {sup 129}Xe-induced reactions on several targets ({sup nat}Cu, {sup 89}y, {sup 165}ho, {sup 197}Au) and E/A = 40, 50 and 60 MeV. The probability of emitting n intermediate-mass-fragments is shown to be binomial at each transversal energy and reducible to an elementary binary probability p. For each target and at each bombarding energy, this probability p shows a thermal n… more
Date: January 1, 1995
Creator: Wozniak, G. J.; Tso, K. & Phair, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

An ``exact`` treatment of self-shielding and covers in neutron spectra determinations

Description: Most neutron spectrum determination methodologies ignore self-shielding effects in dosimetry foils and treat covers with an exponential attenuation model. This work provides a quantitative analysis of the approximations in this approach. It also provides a methodology for improving the fidelity of the treatment of the dosimetry sensor response to a level consistent with the user`s spectrum characterization approach. A library of correction functions for the energy-dependent sensor response has … more
Date: June 1, 1995
Creator: Griffin, Patrick J. & Kelly, John G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Radioactive nuclide production and isomeric state branching ratios in P + W reactions to 200 mev

Description: Calculations of nuclide yields from spallation reactions usually assume that the products are formed in their ground states. We are performing calculations of product yields from proton reactions on tungsten isotopes that explicitly account for formation of the residual nuclei in excited states. The Hauser-Feshbach statistical/preequilibrium code GNASH, with full accounting for angular momentum conservation and electromagnetic transitions, is utilized in the calculations. We present preliminary… more
Date: July 1, 1995
Creator: Young, P.G. & Chadwick, M.B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Evaluated cross-section libraries and kerma factors for neutrons up to 100 MeV on {sup 12}C

Description: A program is being carried out at Lawrence Livermore National Laboratory to develop high-energy evaluated nuclear data libraries for use in Monte Carlo simulations of cancer radiation therapy. In this report we describe evaluated cross sections and kerma factors for neutrons with incident energies up to 100 MeV on {sup 12}C. The aim of this effort is to incorporate advanced nuclear physics modeling methods, with new experimental measurements, to generate cross section libraries needed for an ac… more
Date: April 11, 1995
Creator: Chadwick, M.B.; Blann, M.; Cox, L.; Young, P.G. & Meigooni, A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Characterization of silicon implanted SiO{sub 2} layers using positron annihilation spectroscopy

Description: Silicon implanted thermal SiO{sub 2} layers were studied using depth-resolved positron annihilation spectroscopy (PAS) and transmission electron microscopy (TEM). TEM observations show the presence of silicon nanocrystals (Si{sub nc}) in the region between 200 nm and 200 nm. The defect annealing behavior is studied by means of PAS. For 1000{degrees}C annealed samples at a depth for which Si{sub nc} are observed, a distinctive PAS signal is detected and ascribed to the Si{sub nc}/SiO{sub 2} inte… more
Date: August 1, 1995
Creator: Ghislotti, G.; Nielsen, B.; Asoka-Kumar, P.; Lynn, K. G.; Szeles, C.; Bottani, C. E. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Benchmarking the LAHET{trademark} fission models

Description: There has been considerable interest in improving the fission models in the LAHET Monte Carlo code for the transport and interaction of nucleons, pions, muons, light ions, and antinucleons. Although subactinide fission contributes little to neutron production in lead or tungsten targets, it can be significant for simulation of target activation and fission product contamination. The availability of new data permits new comparisons to be made between experiment and calculation.
Date: July 1, 1995
Creator: Prael, R.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Observation on radiation transfer experiments using k-shell absorption spectra

Description: Recent laser-produced plasma experiments have relied on spectroscopic comparisons with models to infer plasma temperatures. Here, the technique is applied to study thermal radiation transfer experiments. The transmission model combines high-quality atomic data with an ionization balance obtained from systematic expansions of the grand canonical ensemble. The latter avoids the ad hoc cutoffs required in free energy minimization schemes and includes Coulomb corrections usually neglected in other … more
Date: January 4, 1995
Creator: Iglesias, C. A.; Chen, M. H.; McWilliams, D. L.; Nash, J. K. & Rogers, F. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Collective effects in the PEP-II B-factory

Description: The expected major collective effects in the PEP-II B-factory are discussed and thresholds presented. Broadband and narrow band impedance values are reviewed. Instabilities not related to impedance are discussed.
Date: October 1, 1995
Creator: Corlett, J.N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Nuclear structure studies via neutron interactions. Progress report, 1 July 1994--30 June 1995

Description: Neutron total cross section measurements of {sup 122}Sn has been analyzed over the energy range 0.013 to 0.310 MeV. The R - matrix analysis has resulted in resonance and average parameters which provide for a complete representation of the neutron entrance the s{sub 1/2}, p{sub 1/2}, and p{sub 3/2} contributions. The s - and p - neutron strength functions have been determined to be 0.123 {plus_minus} 0.023 and 2.0 {plus_minus} 0.200, respectively (in units of 10{sup {minus}4}). Limits are place… more
Date: January 1, 1995
Creator: Carlton, R.F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Neutron Scattering and Models: Iron. Nuclear Data and Measurements Series

Description: Differential elastic and inelastic neutron-scattering cross sections of elemental iron are measured from 4.5 to 10 MeV in increments of {approx} 0.5 MeV. At each incident energy the measurements are made at forty or more scattering angles distributed between {approx} 17{degrees} and 160{degrees}, with emphasis on elastic scattering and inelastic scattering due to the excitation of the yrast 2{sup +} state. The measured data is combined with earlier lower-energy results from this laboratory, wit… more
Date: August 1995
Creator: Smith, A. B.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Effects of shape differences in the level densities of three formalisms of calculated cross sections

Description: Effects of shape differences in the level densities of three formalisms on calculated cross sections and particle emission spectra are described. Reactions for incident neutrons up to 20 MeV on {sup 58}Ni are chosen for illustrations. Level-density parameters for one of the formalisms are determined from the available neutron resonance data for one residual nuclide in the binary channels and from fitting the measured (n, n{prime}), (n, p), and (n, {alpha}) cross sections for the other two resid… more
Date: September 1, 1995
Creator: Fu, C.Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Reducible emission probabilities and thermal scaling in multifragmentation

Description: Intermediate-mass-fragment multiplicity distributions for a variety of reactions at intermediate energies are shown to be binomial and thus reducible at all measured transverse energies. From these distributions a single binary event probability can be extracted that has a thermal dependence. A strong thermal signature is also found in the charge distributions. The {eta}-fold charge distributions are reducible to the {eta}-fold charge distributions through a simple scaling that is dictated by f… more
Date: August 1, 1995
Creator: Moretto, L. G.; Phair, L. & Tso, K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Calculations of the giant-dipole-resonance photoneutrons using a coupled EGS4-morse code

Description: The production and transport of the photoneutrons from the giant-dipoleresonance reaction have been implemented in a coupled EGS4-MORSE code. The total neutron yield (including both the direct neutron and evaporation neutron components) is calculated by folding the photoneutron yield cross sections with the photon track length distribution in the target. Empirical algorithms based on the measurements have been developed to estimate the fraction and energy of the direct neutron component for eac… more
Date: October 1, 1995
Creator: Liu, J. C.; Nelson, W. R.; Kase, K. R. & Mao, X. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Evaluated cross section libraries and kerma factors for neutrons up to 100 MeV on {sup 16}O and {sup 14}N

Description: We present evaluations of the interaction of 20 to 100 MeV neutrons with oxygen and nitrogen nuclei, which follows on from our previous work on carbon. Our aim is to accurately represent integrated cross sections, inclusive emission spectra, and kerma factors, in a data library which can be used in radiation transport calculations. We apply the FKK-GNASH nuclear model code, which includes Hauser-Feshbach, preequilibrium, and direct reaction mechanisms, and use experimental measurements to optim… more
Date: July 1, 1995
Creator: Chadwick, M.B. & Young, P.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Performance of long-pulse source reference target-moderator-reflector configurations

Description: We have calculated the performance of five similar target-moderator-reflector geometries that are reasonably well optimized for long-pulse source applications. For all cases, the moderators are fully coupled; that is, no poisons, decouplers, or liners are used. For each case, the energy- and time-dependent characteristics of the moderator source brightness have been parameteterized using empirical functions. These parameterizations have been made available to users of the Monte Carlo neutron sc… more
Date: December 31, 1995
Creator: Pitcher, E. J.; Russell, G. J.; Seeger, P. A. & Ferguson, P. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The cost of transportation`s oil dependence

Description: Transportation is critical to the world`s oil dependence problem because of the large share of world oil it consumes and because of its intense dependence on oil. This paper will focus on the economic costs of transportation`s oil dependence.
Date: May 1, 1995
Creator: Greene, D. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Top quark physics

Description: Most of the material presented in this report, comes from contributions to the parallel session PL20 of this conference. We summarise the experimental results of direct production of Top quarks, coming from the CDF and C0 Collaborations at Fermilab, and compare these results to what one expects within current theoretical understanding. Particular attention is given to new results such as all hadronic modes of t{bar t} decay. As far as the mass is concerned, a comparison is made with precision m… more
Date: October 1, 1995
Creator: Menzione, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Rapid increase in prescission GDR {gamma}-ray emission with energy

Description: A rapid increase in the emission of prescission giant dipole resonance (GDR) {gamma}-rays with bombarding energy is observed in excited Th and Cf nuclei formed in the reactions {sup 16}O+{sup 20B}Pb and {sup 32}S+{sup nat}W,{sup 208}Pb. This increase begins around E{sub exc} = 40 MeV for the {sup 16}O+{sup 208}Pb reaction and E{sub exc} = 70 MeV for the {sup 32}S-induced reactions. The excess {gamma}-ray yield above these thresholds cannot be described within the standard statistical model. Sta… more
Date: December 31, 1995
Creator: Hofman, D.J.; Back, B.B. & Paul, P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Influence of the deuteron energy on the testing volume of IFMIF and its impact on other parameters

Description: The influence of the energy of the deuteron beam on irradiation parameters of IFMIF is analyzed. The main purpose of this paper is to identify possible positive and negative impacts on irradiation parameters that an increase in the deuteron energy of the beam can cause. Several parameters of the facility, such as neutron generation rate, number of neutrons with energy above 20 MeV at the source and in the test assembly, volume with dpa rate above a threshold value, gas production, and gradient … more
Date: September 1, 1995
Creator: Gomes, I. C. & Smith, D. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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