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Covariance analysis of n + 7Li data for ENDF/B-VI

Description: A new covariance analysis of n/plus//sup 7/Li experimental data has been completed for Version VI of ENDFB. The analysis basically updates our 1981 work for ENDFB-V.2 to include new data that has become available since that time and to incorporate cross correlations between different experiments. The bulk of the new measured data consists of some 10 new (or newly revised) tritium-production measurements involving about 70 new data points. The new analysis results in only small changes in the pr… more
Date: January 1, 1988
Creator: Young, P.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Application of nuclear models to neutron nuclear cross section calculations

Description: Nuclear theory is used increasingly to supplement and extend the nuclear data base that is available for applied studies. Areas where theoretical calculations are most important include the determination of neutron cross sections for unstable fission products and transactinide nuclei in fission reactor or nuclear waste calculations and for meeting the extensive dosimetry, activation, and neutronic data needs associated with fusion reactor development, especially for neutron energies above 14 Me… more
Date: January 1, 1982
Creator: Young, P.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The status of nuclear data evaluations for Version VI of ENDF/B

Description: A new version of the United States national evaluated nuclear data file, ENDF/B-VI, is nearing completion. Major emphasis is being placed on correcting some long-standing nuclear data problems that adversely affect applied calculations for fission and fusion reactors. This paper reviews some of the evaluation activities of most revelance for fission reactor applications, namely, those involving control, cooling, and shielding materials, structural elements, and the major actinides. Additionally… more
Date: January 1, 1988
Creator: Young, P.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Global and local optical model parameterizations. [A > 40, 10 keV-20 MeV]

Description: A review is given of global and regional phenomenological neutron optical model parameterizations in the mass region above A = 40 and for neutron energies in the range 10 keV to 20 MeV. The performance of some 11 different neutron parameterizations is investigated for the case of /sup 58/Ni, utilizing Hauser-Feshbach statistical theory calculations of several reactions. A similar, more restricted analysis is made for neutron reactions on /sup 165/Ho, demonstrating the use of two useful approxim… more
Date: January 1, 1985
Creator: Young, P.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Review of evaluated cross section data for air and ground constituents

Description: From EMP technical meeting; Kirtland AFB, New Mexico, USA (25 Sep 1973). During the past few years the Defense Nuclear Agency has sponsored a radiation transport program that has the goal of substantially reducing uncertainties in predictions of radiation environments. Important aspects of the program have been to provide new cross section measurements directed particularly at areas of ignorance in the data for several important materials and to maintain up-to-date cross section evaluations tha… more
Date: January 1, 1973
Creator: Young, P.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Summary documentation of LASL nuclear data evaluations for ENDF/B-V

Description: Summaries are presented of nuclear data evaluations performed at Los Alamos Scientific Laboratory (LASL) that will comprise part of Version V of the Evaluated Nuclear Data File, ENDF/B. A total of 18 general purpose evaluations of neutron-induced data are summarized, together with 6 summaries directed specifically at covariance data evaluations. The general purpose evaluation summaries cover the following isotopes: /sup 1 -3/H, /sup 3/ /sup 4/He, /sup 6/ /sup 7/Li, /sup 10/B, /sup 14/ /sup 15/N… more
Date: January 1, 1979
Creator: Young, P.G. (comp.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Evaluated data for n + /sup 9/Be reactions. [10/sup -5/ eV to 20 MeV]

Description: A new evaluation of neutron-induced reactions on /sup 9/Be was completed for the energy range 10/sup -5/ eV to 20 MeV. Particular emphasis was placed on accurately representing new measurements of secondary neutron-emission spectra and scattering data between 6 and 15 MeV. Additionally, adjustments to the total, (n,..gamma..), and (n,t) cross sections in previous ENDF/B evaluations were made, and covariance data files that contain error correlations for the cross sections and emission spectra w… more
Date: July 1, 1979
Creator: Young, P.G. & Stewart, L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Evaluation of neutron cross sections to 40 MeV for /sup 54/ /sup 56/Fe

Description: Cross sections for neutron-induced reactions on /sup 54/ /sup 56/Fe were calculated by employing several nuclear models: optical, Hauser-Feshbach, preequilibrium and DWBA - in the energy range between 3 and 40 MeV. As a prelude to the calculations, the necessary input parameters were determined or verified through analysis of a large body of experimental data for both neutron- and proton-induced reactions in this mass and energy region. This technique also led to cross sections in which the sim… more
Date: January 1, 1980
Creator: Arthur, E. D. & Young, P. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Calculation of neutron cross sections on iron between 3 and 40 MeV. [Hauser-Feshbach model]

Description: The use of high energy d+Li sources to produce neutrons for radiation damage studies will require evaluated neutron cross sections up to energies of 40 MeV. Experimental data in this energy region are scarce, and reliance must be placed upon nuclear model calculations to provide the necessary cross sections. We have thus calculated neutron-induced cross sections on /sup 54/Fe and /sup 56/Fe between 3 and 40 MeV using the multistep preequilibrium Hauser-Feshbach model code GNASH. Special care wa… more
Date: January 1, 1979
Creator: Arthur, E. D. & Young, P. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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GNASH: a preequilibrium, statistical nuclear-model code for calculation of cross sections and emission spectra. [In FORTRAN for CDC 7600]

Description: A new multistep Hauser--Feshbach code that includes corrections for preequilibrium effects is described. The code can calculate up to 60 decay reactions (cross sections and energy spectra) in one computation, and thereby provide considerable flexibility for handling processes with complicated reaction chains. Input parameter setup, problem output, and subroutine descriptions are given along with a sample problem calculation. A brief theoretical description is also included. 8 figures, 3 tables.
Date: November 1, 1977
Creator: Young, P. G. & Arthur, E. D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Calculation of neutron cross sections on iron up to 40 MeV

Description: The development of high energy d + Li neutron sources for fusion materials radiation damage studies will require neutron cross sections up to 40 MeV. Experimental data above 15 MeV are generally sparse or nonexistent, and reliance must be placed upon nuclear-model calculations to produce the needed cross sections. To satisfy such requirements for the Fusion Materials Irradiation Test Facility (FMIT), neutron cross sections have been calculated for /sup 54/ /sup 56/Fe between 3 and 40 MeV. These… more
Date: January 1, 1980
Creator: Arthur, E. D. & Young, P. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Calculated medium-energy fission cross sections

Description: Calculations were made of neutron-induced fission cross sections on /sup 238/U and /sup 237/Np to compare with new data available up to 100 MeV. This process also produced fission barrier parameters for neptunium and uranium compound systems required for calculation of p + /sup 238/U fission cross sections. To achieve reasonable agreement with higher energy neutron-induced fission data, a phenomenological enhancement to barrier heights based upon the average angular momentum of the compound sys… more
Date: January 1, 1988
Creator: Arthur, E. D. & Young, P. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Evaluation of n + /sup 242/Pu reactions from 10 keV to 20 MeV. [Data compilation, cross sections, angular distributions]

Description: An evaluation of the n + /sup 242/Pu cross sections is presented for the neutron energy range of 10 keV to 20 MeV. The total fission and radiative capture cross sections are based upon experimental measurements of /sup 242/Pu. The remaining cross sections, together with the elastic and inelastic angular distributions to low lying states were calculated using various reaction models. An expression is presented for the energy dependence of the average number of neutrons produced per fission. The … more
Date: January 1, 1978
Creator: Madland, D.G. & Young, P.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Review of new developments in fusion reactor nucleonics

Description: A review is presented of recent developments in nuclear data, computational methods, and computer codes, especially as pertains to fusion reactor nucleonics. Important nuclear data measurements, evaluations, nuclear model codes and processing codes are discussed. Progress in solution acceleration and deterministic streaming methods for discrete-ordinates codes is covered, along with comments on recent Monte Carlo developments. Finally, sensitivity and uncertainty analysis methods are reviewed.
Date: January 1, 1980
Creator: Dudziak, D.J. & Young, P.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Analysis of n + /sup 197/Au cross sections for E/sub n/ = 0. 01-20 MeV

Description: An analysis of n + /sup 197/Au reactions has been completed for incident neutron energies between 0.01 and 20 MeV. The analysis involves use of a deformed optical model to calculate neutron transmission coefficients, a giant-dipole-resonance model and experimental data to determine gamma-ray transmission coefficients, and Hauser-Feshbach statistical theory to calculate partial reaction cross sections. Particular emphasis was given to obtaining gamma-ray strength functions that are consistent wi… more
Date: September 9, 1984
Creator: Young, P. G. & Arthur, E. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Calculation of /sup 235/U(n,n') cross sections for ENDF/B-VI

Description: Cross sections for neutron-induced reactions on /sup 235/U between 0.01 and 20 MeV have been calculated in a preliminary analysis for the ENDF/B-VI evaluation with particular emphasis on neutron inelastic scattering. A deformed optical model potential that fits total, elastic, inelastic, and low-energy average resonance data is used to calculate direct (n,n') cross sections and transmission coefficients for a Hauser-Feshbach statistical theory analysis using a multiple fission barrier represent… more
Date: January 1, 1988
Creator: Young, P. G. & Arthur, E. D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Evaluation of n + /sup 242/Pu reactions from 10 keV to 20 MeV. [Total cross sections, neutron emission energy dependence]

Description: An evaluation of the n + /sup 242/Pu cross sections is presented for the neutron energy range of 10 keV to 20 MeV. The total fission and radiative capture cross sections are based upon experimental measurements on /sup 242/Pu. The remaining cross sections, together with the elastic and inelastic angular distributions to low-lying states, were calculated using various reaction models. An expression is presented for the energy dependence of the average number of neutrons produced per fission. The… more
Date: October 1, 1978
Creator: Madland, D.G. & Young, P.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Cross sections in the energy range from 10 to 40 MeV calculated with the GNASH code. [GNASA, below 40 MeV]

Description: A brief description of the preequilibrium-statistical model code GNASH is given. Features which make the code applicable to the calculation of cross sections induced by nucleons of energy 40 MeV or less are described. Finally, examples of calculations of neutron- and proton-induced reaction cross sections, activation cross sections, and secondary spectra made with global input parameters are given.
Date: January 1, 1977
Creator: Arthur, E. D. & Young, P. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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ENDF-201 Supplement 1. ENDF/B-V. 2 Summary Documentation. Third Edition

Description: The purpose of the present publication is to provide the summary documentation for Revision 2 of the General Purpose File of ENDF/B-V. Revision 2 embodies a series of updates for important materials in the ENDF/B-V libraries in advance of the more comprehensive changes that will accompany a complete version change to ENDF/B, Verison VI. The summary documents for the evaluations that were completely or extensively modified during Revision 2 are provided. Less extensive changes made to other eval… more
Date: January 1, 1985
Creator: Magurno, B. A. & Young, P. G. (comps.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Key changes in nuclear data in the transition from ENDF/B-V to ENDF/B- VI

Description: Major changes were made in the evaluated nuclear data base in going from ENDF/B-V to ENDF/B-VI. A complete revision of all the cross sections standards was implemented using results from a simultaneous analysis of all standard reactions; energy-angle correlated secondary distributions for emitted particles and gamma rays were introduced; many natural element evaluations were replaced by isotopic data; vastly expanded fission-product yield and decay data files were included; and altogether some … more
Date: January 1, 1991
Creator: Young, P.G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Applied nuclear data research and development. Progress report, July 1--September 30, 1978

Description: Activities of the Los Alamos Nuclear Data Group for the period July 1 through September 30, 1978, are described. Work was performed in the following subject areas: theory and evaluation of nuclear cross sections; nuclear cross-section processing; and fission products and actinides--yields, yield theory, decay data, depletion, and buildup. Separate abstracts were prepared for four sections that contained significant amounts of data. 18 figures, 12 tables. (RWR)
Date: December 1, 1978
Creator: Baxman, C.I. & Young, P.G. (comps.)
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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