Analysis of NeutronDouble-Differential Cross Sectionsfor n+12C Reaction Below 30 MeV

Abstract

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