PRACTICAL METHOD FOR ESTIMATING NEUTRON CROSS SECTION COVARIANCES IN THE RESONANCE REGION

Cho, Y.S. ; Oblozinsky, P. ; Mughabghab,S.F. ; Mattoon,C.M. ; Herman,M.

Brookhaven National Laboratory

关键词: Approximations;    Kernels;    Neutrons;    Cross Sections;    72 Physics Of Elementary Particles And Fields;   

DOI  :  10.2172/1013489
RP-ID  :  BNL--93617-2010
RP-ID  :  DE-AC02-98CH10886
RP-ID  :  1013489

美国|英语

来源: UNT Digital Library

【 摘 要 】

Recent evaluations of neutron cross section covariances in the resolved resonance region reveal the need for further research in this area. Major issues include declining uncertainties in multigroup representations and proper treatment of scattering radius uncertainty. To address these issues, the present work introduces a practical method based on kernel approximation using resonance parameter uncertainties from the Atlas of Neutron Resonances. Analytical expressions derived for average cross sections in broader energy bins along with their sensitivities provide transparent tool for determining cross section uncertainties. The role of resonance-resonance and bin-bin correlations is specifically studied. As an example we apply this approach to estimate (n,{gamma}) and (n,el) covariances for the structural material {sup 55}Mn.