Calculation of Prompt Fission Neutron from233U(n, f) Reaction by Multi-Modal Los Alamos Model

An attempt is made to improve the evaluation of the prompt fission neutron emission from 233U(n, f) reaction for incident neutron energies below 6 MeV. The multi-modal fission approach is applied to the improved version of Los Alamos model and the point by point model. The prompt fission neutron spectra and the prompt fission neutron as a function of fragment mass (usually named "sawtooth" data) υ(A) are calculated independently for the three most dominant fission modes (standard I, standard II and superlong), and the total spectra and υ(A) are synthesized. The multi-modal parameters are determined on the basis of experimental data of fission fragment mass distributions. The present calculation results can describe the experimental data very well, and the proposed treatment is thus a useful tool for prompt fission neutron emission prediction.