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Title: Neutron Capture Gamma-Ray Libraries for Nuclear Applications

Abstract

The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. This can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research Project. EGAF is being used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90% of all the decay energy and is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there ismore » less experimental data available making benchmarking of the modeling codes more difficult. We are investigating the capture spectra from higher energy neutrons experimentally using surrogate reactions and modeling this with Hauser-Feshbach codes. This can then be used to benchmark CASINO, a version of DICEBOX modified for neutron capture at higher energy. This can be used to simulate spectra from neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modeling of unknown assemblies.« less

Authors:
; ;  [1]; ;  [2];  [1];  [3]; ; ;  [4];  [5]
  1. Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)
  2. Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
  3. Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, CZ-180 00 Prague 8 (Czech Republic)
  4. Institute of Isotope and Surface Chemistry, H-1525, Budapest (Hungary)
  5. Seoul National University, Republic of Korea and Department of Physics, University of Hankook, Seoul, 120-424 (Korea, Republic of)
Publication Date:
OSTI Identifier:
21513486
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 1342; Journal Issue: 1; Conference: 2. international Ulaanbaatar conference on nuclear physics and applications, Ulaanbaatar (Mongolia), 26-30 Jul 2010; Other Information: DOI: 10.1063/1.3583170; (c) 2011 American Institute of Physics; Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ACCURACY; CAPTURE; CROSS SECTIONS; ENERGY LEVELS; EVALUATION; GAMMA CASCADES; GAMMA RADIATION; GAMMA SPECTRA; HEAVY NUCLEI; IAEA; ISOTOPES; MEV RANGE 10-100; NEUTRON REACTIONS; NEUTRON SOURCES; NEUTRON TRANSPORT THEORY; NUCLEAR DATA COLLECTIONS; NUCLEAR DECAY; NUCLEAR STRUCTURE; SIMULATION; THERMAL NEUTRONS; BARYON REACTIONS; BARYONS; DECAY; ELECTROMAGNETIC RADIATION; ELEMENTARY PARTICLES; ENERGY RANGE; ENERGY-LEVEL TRANSITIONS; FERMIONS; HADRON REACTIONS; HADRONS; INTERNATIONAL ORGANIZATIONS; IONIZING RADIATIONS; MEV RANGE; NEUTRONS; NUCLEAR CASCADES; NUCLEAR REACTIONS; NUCLEI; NUCLEON REACTIONS; NUCLEONS; PARTICLE SOURCES; RADIATION SOURCES; RADIATIONS; SPECTRA; TRANSPORT THEORY

Citation Formats

Sleaford, B W, Summers, N, Escher, J, Firestone, R B, Basunia, S, Hurst, A, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, Krticka, M, Molnar, G, Belgya, T, Revay, Z, and Choi, H D. Neutron Capture Gamma-Ray Libraries for Nuclear Applications. United States: N. p., 2011. Web. doi:10.1063/1.3583170.
Sleaford, B W, Summers, N, Escher, J, Firestone, R B, Basunia, S, Hurst, A, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, Krticka, M, Molnar, G, Belgya, T, Revay, Z, & Choi, H D. Neutron Capture Gamma-Ray Libraries for Nuclear Applications. United States. doi:10.1063/1.3583170.
Sleaford, B W, Summers, N, Escher, J, Firestone, R B, Basunia, S, Hurst, A, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, Krticka, M, Molnar, G, Belgya, T, Revay, Z, and Choi, H D. Tue . "Neutron Capture Gamma-Ray Libraries for Nuclear Applications". United States. doi:10.1063/1.3583170.
@article{osti_21513486,
title = {Neutron Capture Gamma-Ray Libraries for Nuclear Applications},
author = {Sleaford, B W and Summers, N and Escher, J and Firestone, R B and Basunia, S and Hurst, A and Lawrence Berkeley National Laboratory, Berkeley, CA 94720 and Krticka, M and Molnar, G and Belgya, T and Revay, Z and Choi, H D},
abstractNote = {The neutron capture reaction is useful in identifying and analyzing the gamma-ray spectrum from an unknown assembly as it gives unambiguous information on its composition. This can be done passively or actively where an external neutron source is used to probe an unknown assembly. There are known capture gamma-ray data gaps in the ENDF libraries used by transport codes for various nuclear applications. The Evaluated Gamma-ray Activation file (EGAF) is a new thermal neutron capture database of discrete line spectra and cross sections for over 260 isotopes that was developed as part of an IAEA Coordinated Research Project. EGAF is being used to improve the capture gamma production in ENDF libraries. For medium to heavy nuclei the quasi continuum contribution to the gamma cascades is not experimentally resolved. The continuum contains up to 90% of all the decay energy and is modeled here with the statistical nuclear structure code DICEBOX. This code also provides a consistency check of the level scheme nuclear structure evaluation. The calculated continuum is of sufficient accuracy to include in the ENDF libraries. This analysis also determines new total thermal capture cross sections and provides an improved RIPL database. For higher energy neutron capture there is less experimental data available making benchmarking of the modeling codes more difficult. We are investigating the capture spectra from higher energy neutrons experimentally using surrogate reactions and modeling this with Hauser-Feshbach codes. This can then be used to benchmark CASINO, a version of DICEBOX modified for neutron capture at higher energy. This can be used to simulate spectra from neutron capture at incident neutron energies up to 20 MeV to improve the gamma-ray spectrum in neutron data libraries used for transport modeling of unknown assemblies.},
doi = {10.1063/1.3583170},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 1342,
place = {United States},
year = {2011},
month = {6}
}