Evaluation of Nonelastic Neutron Cross Sections on Carbon above 14 MeV

Abstract

Neutron cross sections on carbon at and above 14 MeV are of interest for a variety of applications. It is argued that the ENDF/B-V evaluation of the nonelastic cross sections is in some error; this is due in part to the ''subtraction'' technique used for evaluating the nonelastic cross section, and to an overreliance on old nuclear emulsion data. In addition, secondary uncharged- (and, for biomedical applications, charged-) particle spectra are important. It is shown that kerma-factor calculations are very sensitive to the secondary charged-particle spectrum. Thus an assessment of the reaction mechanisms, leading to evaluated secondary particle spectra, is also needed.