Neutron-induced reactions in medium mass nuclei

Abstract

In the neutron energy range below 20 MeV about 20 neutron reactions are energetically possible. These reactions are analyzed using a statistical model. Since direct reaction effects can be important the calculations are normalized to experiment so as to partly compensate for deficiencies in the model. The empirical model is similar to previous work used to describe (n, 2n) reactions but is extended to included charged particle emission. Relatively good agreement is obtained with measured excitation curves and 14 MeV cross-sections using a single set of fitting constants. The method of analysis has been incorporated into a computer code THRESH. For crude calculations the code requires only Z and A as input but improved fits in individual cases can be attained through simple parameter variation. Cross-sections and fission spectrum averages are calculated for nuclides in the range Z = 21−41.