Covariances Obtained from an Evaluation of the Neutron Cross Section Standards

Journal Article · Mon Dec 15 00:00:00 EST 2008 · Nuclear Data Sheets

DOI:https://doi.org/10.1016/j.nds.2008.11.019· OSTI ID:21163777

Badikov, S A ^[1]; Chen, Zhenpeng ^[2]; Gai, E ^[3]; Hale, G M ^[4]; Hambsch, F -J ^[5]; Hofmann, H M ^[6]; Kawano, T ^[4]; Larson, N M ^[7]; Oh, S Y ^[8]; Pronyaev, V G ^[3]; Smith, D L ^[9]; Tagesen, S; Vonach, H ^[10]

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1. Central Research Institute of Management, Economics and Information, Moscow (Russian Federation)
2. Tsinghua University, Beijing (China)
3. Institute of Physics and Power Engineering, Obninsk, Kaluga Region (Russian Federation)
4. Los Alamos National Laboratory, Los Alamos, NM (United States)
5. Institute for Reference Materials and Measurements, Geel (Belgium)
6. Erlangen-Nuernberg University, Erlangen (Germany)
7. Oak Ridge National Laboratory, Oak Ridge, TN (United States)
8. Korea Atomic Energy Research Institute, Yuseong, Daejeon (Korea, Republic of)
9. Argonne National Laboratory, Argonne, IL (United States)
10. Vienna University, Vienna (Austria)

New measurements and an improved evaluation process were used to obtain a new evaluation of the neutron cross section standards. Efforts were made to include as much information as possible on the components of the data uncertainties that were then used to obtain the covariance matrices for the experimental data. Evaluations were produced from this process for the {sup 6}Li(n,t), {sup 10}B(n,{alpha}), {sup 10}B(n,{alpha}{sub 1}{gamma}), {sup 197}Au(n,{gamma}), {sup 235}U(n,f), and {sup 238}U(n,f) standard cross sections as well as the non-standard {sup 6}Li(n,n), {sup 10}B(n,n), {sup 238}U(n,{gamma}) and {sup 239}Pu(n,f) cross sections. There is a general increase in the cross sections for most of the new evaluations, by as much as about 5%, compared with the ENDF/B-VI results. Covariance data were obtained for the {sup 6}Li(n,t), {sup 6}Li(n,n), {sup 10}B(n,{alpha}), {sup 10}B(n,{alpha}{sub 1}{gamma}), {sup 10}B(n,n), {sup 197}Au(n,{gamma}), {sup 235}U(n,f), {sup 238}U(n,f), {sup 238}U(n,{gamma}) and {sup 239}Pu(n,f) reactions. Also an independent R-Matrix evaluation was produced for the H(n,n) standard cross-section, however, covariance data are not available for this reaction. The evaluations were used in the new ENDF/B-VII library.

• OSTI ID: 21163777
• Journal Information: Nuclear Data Sheets, Vol. 109, Issue 12; Conference: Workshop on neutron cross section covariances, Port Jefferson, NY (United States), 24-28 Jun 2008; Other Information: DOI: 10.1016/j.nds.2008.11.019; PII: S0090-3752(08)00107-5; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0090-3752
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BORON 10 TARGET
CROSS SECTIONS
DATA COVARIANCES
EVALUATED DATA
EVALUATION
EXPERIMENTAL DATA
GAMMA RADIATION
GOLD 197 TARGET
LITHIUM 6 TARGET
NEUTRON REACTIONS
NEUTRONS
NUCLEAR DATA COLLECTIONS
PLUTONIUM 239 TARGET
R MATRIX
URANIUM 235 TARGET
URANIUM 238 TARGET