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Title: Pre-equilibrium, Statistical Nuclear-Model Code System for Calculation Cross Sections and Emission Spectra, Version gn9cp8.

Abstract

Version 00 GNASH provides a flexible method by which reaction and level cross sections, isomer ratios, and emission spectra (neutron, gamma-ray, and charged-particle) resulting from particle- and photon-induced reactions can be calculated. The September 1991 release of GNASH incorporated an additional option for calculating gamma-ray strength functions and transmission coefficients by including the Kopecky-Uhl model. In addition, improvements were made to the output routines, particularly regarding gamma-ray strength function information. Major improvements in the 1995 FKK-GNASH release include added capabilities: to read in externally calculated preequilibrium spectrum from, e.g., Feshbach-Kerman-Koonin theory, to do multiple preequilibrium calculations, to calculate appropriate spin distributions for nuclear states formed in preequilibrium reactions, and to do incident-photon calculations. In the 1998 release improvements were made in the accuracy of the exciton model and other calculations, and provision was made for including energy-dependent renormalization of the reaction cross section and energy-dependent exciton model parameterization (for data evaluation purposes). The sample problems provided here are the same as those that were given in the 1998 release; however, the calculations were run using the current version of GNASH (gn9cp8). The major differences between this version and the previous one released in 1998 are as follows: 1. A seriousmore » buffering error that affected stored state populations resulting when multiple reactions lead to the same compound nucleus is corrected. This error only affects cases with INPOPT=-1, normally used for high-energy calculations. It is the reason that the present outputs for the p + Zr90 test case (described below) are significantly different from the 1998 results for the same p + Zr90 test case. 2. Minor errors were corrected in estimating preequilibrium contributions to discrete states; interpolating the spin cutoff parameter in the constant temperature region; and in combining inputted direct reaction contributions with preequilibrium contributions. In the cases we checked, these errors resulted in very small differences. 3. The present code utilizes the ground-state masses, spins, and parities from the RIPL-2 database at the IAEA database in Vienna. These are included in the gs-mass-sp.dat file. 4. We modified the SPECTRA subroutine so that when IGAMCAS=2, primary gamma-ray cross sections are not included in the computed spectra. 5. An option for energy-dependent single-particle state densities (GG) used in preequilibrium calculations was added. 6. Several new diagnostic print options were added. 7. Several variable dimensions were increased.« less

Authors:
;
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1271199
Report Number(s):
GNASH-FKK; 004369WKSTN00
RSICC ID: P00535MNYCP
DOE Contract Number:
AC05-00OR22725
Resource Type:
Software
Software Revision:
00
Software Package Number:
004369
Software CPU:
WKSTN
Source Code Available:
Yes
Other Software Info:
Owner Installation: LOS ALAMOS NATIONAL LABORATORY Contributors: Los Alamos National Laboratory, Los Alamos, New Mexico. GNASH uses Hauser-Feshbach theory to calculate complicated sequences of reactions and includes a pre-equilibrium correction for binary tertiary channels. Gamma-ray competition is considered in detail for every decaying compound nucleus. A multi-humped fission barrier model is included for fission cross-section calculations. Three options for level densities are available. KEYWORDS: NUCLEAR MODELS; WORKSTATION; CROSS SECTION PROCESSING; ENDF
Country of Publication:
United States

Citation Formats

PHILLIP,, and YOUNG, G. Pre-equilibrium, Statistical Nuclear-Model Code System for Calculation Cross Sections and Emission Spectra, Version gn9cp8.. Computer software. Vers. 00. USDOE. 2 Feb. 2007. Web.
PHILLIP,, & YOUNG, G. (2007, February 2). Pre-equilibrium, Statistical Nuclear-Model Code System for Calculation Cross Sections and Emission Spectra, Version gn9cp8. (Version 00) [Computer software].
PHILLIP,, and YOUNG, G. Pre-equilibrium, Statistical Nuclear-Model Code System for Calculation Cross Sections and Emission Spectra, Version gn9cp8.. Computer software. Version 00. February 2, 2007.
@misc{osti_1271199,
title = {Pre-equilibrium, Statistical Nuclear-Model Code System for Calculation Cross Sections and Emission Spectra, Version gn9cp8., Version 00},
author = {PHILLIP, and YOUNG, G.},
abstractNote = {Version 00 GNASH provides a flexible method by which reaction and level cross sections, isomer ratios, and emission spectra (neutron, gamma-ray, and charged-particle) resulting from particle- and photon-induced reactions can be calculated. The September 1991 release of GNASH incorporated an additional option for calculating gamma-ray strength functions and transmission coefficients by including the Kopecky-Uhl model. In addition, improvements were made to the output routines, particularly regarding gamma-ray strength function information. Major improvements in the 1995 FKK-GNASH release include added capabilities: to read in externally calculated preequilibrium spectrum from, e.g., Feshbach-Kerman-Koonin theory, to do multiple preequilibrium calculations, to calculate appropriate spin distributions for nuclear states formed in preequilibrium reactions, and to do incident-photon calculations. In the 1998 release improvements were made in the accuracy of the exciton model and other calculations, and provision was made for including energy-dependent renormalization of the reaction cross section and energy-dependent exciton model parameterization (for data evaluation purposes). The sample problems provided here are the same as those that were given in the 1998 release; however, the calculations were run using the current version of GNASH (gn9cp8). The major differences between this version and the previous one released in 1998 are as follows: 1. A serious buffering error that affected stored state populations resulting when multiple reactions lead to the same compound nucleus is corrected. This error only affects cases with INPOPT=-1, normally used for high-energy calculations. It is the reason that the present outputs for the p + Zr90 test case (described below) are significantly different from the 1998 results for the same p + Zr90 test case. 2. Minor errors were corrected in estimating preequilibrium contributions to discrete states; interpolating the spin cutoff parameter in the constant temperature region; and in combining inputted direct reaction contributions with preequilibrium contributions. In the cases we checked, these errors resulted in very small differences. 3. The present code utilizes the ground-state masses, spins, and parities from the RIPL-2 database at the IAEA database in Vienna. These are included in the gs-mass-sp.dat file. 4. We modified the SPECTRA subroutine so that when IGAMCAS=2, primary gamma-ray cross sections are not included in the computed spectra. 5. An option for energy-dependent single-particle state densities (GG) used in preequilibrium calculations was added. 6. Several new diagnostic print options were added. 7. Several variable dimensions were increased.},
doi = {},
year = {Fri Feb 02 00:00:00 EST 2007},
month = {Fri Feb 02 00:00:00 EST 2007},
note =
}

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