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Title: An analytic approach to probability tables for the unresolved resonance region

Authors:
;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
OSTI Identifier:
1347378
Report Number(s):
BNL-113665-2017-CP
DOE Contract Number:
SC00112704
Resource Type:
Conference
Resource Relation:
Conference: International Conference on Nuclear Data for Science and Technology; Bruges, Belgium; 20160911 through 20160916
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS

Citation Formats

Brown D., and Kawano, T. An analytic approach to probability tables for the unresolved resonance region. United States: N. p., 2016. Web.
Brown D., & Kawano, T. An analytic approach to probability tables for the unresolved resonance region. United States.
Brown D., and Kawano, T. 2016. "An analytic approach to probability tables for the unresolved resonance region". United States. doi:. https://www.osti.gov/servlets/purl/1347378.
@article{osti_1347378,
title = {An analytic approach to probability tables for the unresolved resonance region},
author = {Brown D. and Kawano, T.},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 9
}

Conference:
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  • A new module, PURM (Probability tables for the Unresolved Region using Monte Carlo), has been developed for the AMPX-2000 cross-section processing system. PURM uses a Monte Carlo approach to calculate probability tables on an evaluator-defined energy grid in the unresolved-resonance region. For each probability table, PURM samples a Wigner spacing distribution for pairs of resonances surrounding the reference energy. The resonance distribution is sampled for each spin sequence (i.e., {ell}-J pair), and PURM uses the {Delta}{sub 3}-statistics test to determine the number of resonances to sample for each spin sequence. For each resonance, PURM samples the resonance widths from amore » Chi-square distribution for a specified number of degrees of freedom. Once the resonance parameters are sampled, PURM calculates the total, capture, fission and scatter cross sections at the reference energy using the single-level Breit-Wigner formalism with appropriate treatment for temperature effects. Probability tables have been calculated and compared with NJOY. The probability tables and cross-section values that are calculated by PURM and NJOY are in agreement, and the verification studies with NJOY establish the computational capability for generating probability tables using the new AMPX module PURM.« less
  • An alternate procedure for the generation of cross section probability tables, which is based upon an entirely different principle than the Probability Table method, has been developed by D.E. Cullen and is applicable to any cross section energy range where there is sufficient structure in the cross sections. When this multi-band method is adapted to the unresolved resonance range, the multi-band parameters are determined from moments of the unresolved self-shielded cross sections assuming a Bondarenko form for the self-shielding across individual resonance sequences. The procedure is described. (WHK)
  • The URR computer code has been developed to calculate cross-section probability tables, Bondarenko self-shielding factors, and self- indication ratios for fertile and fissile isotopes in the unresolved resonance region. Monte Carlo methods are utilized to select appropriate resonance parameters and to compute the cross sections at the desired reference energy. The neutron cross sections are calculated by the single-level Breit-Wigner formalism with s-, p-, and d-wave contributions. The cross-section probability tables are constructed by sampling the Doppler broadened cross-section. The various shelf-shielded factors are computed numerically as Lebesgue integrals over the cross-section probability tables. 6 refs.
  • The URR computer code has been developed to calculate cross-section probability tables, Bondarenko self-shielding factors, and self-indication ratios for fertile and fissile isotopes in the unresolved resonance region. Monte Carlo methods are utilized to select appropriate resonance parameters and to compute the cross sections at the desired reference energy. The neutron cross sections are calculated by the single-level Breit-Wigner formalism with s-, p-, and d-wave contributions. The cross-section probability tables are constructed by sampling by Doppler broadened cross-sections. The various self-shielding factors are computer numerically as Lebesgue integrals over the cross-section probability tables.