Analysis of Neutron Double-Differential Cross Sections for n + ~(12)C Reaction Below 30 MeV

摘要

Based on the light nucleus reaction model (Nucl. Sci. Eng. 133 (1999) 218), four aspects (neutron incident energy region, reaction channel analysis, the renewed level schemes and the optical model parameters) of n+ ~(12)C reaction are improved to calculate total outgoing neutron double-differential cross sections with modified LUNF code below 30 MeV. The calculated results agree fairly well with the experimental data at E_n = 14.1 MeV and 18 MeV. The analysis shows that the pre-equilibrium mechanism, which is exactly considered the conservation of energy, momentum and parity, dominates the whole reaction process. The contribution of the neutron emission from ~5He to total energy-angular spectra is also considered properly. This modified LUNF code will be a useful tool to set up the file of neutron double-differential cross sections below 30 MeV in the neutron evaluation nuclear data library.