Neutron Capture Gamma-Ray Libraries for Nuclear Applications

Journal Article · Tue Jun 28 00:00:00 EDT 2011 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.3583170· OSTI ID:21513486

Sleaford, B W; Summers, N; Escher, J ^[1]; Firestone, R B; Basunia, S ^[2]; Hurst, A ^[1]; Krticka, M ^[3]; Molnar, G; Belgya, T; Revay, Z ^[4]; Choi, H D ^[5]

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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)

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.

• OSTI ID: 21513486
• Journal Information: AIP Conference Proceedings, Vol. 1342, 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; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

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