Prompt fission neutron spectrum calculations for n+238U reaction using the multi-modal model

The prompt fission neutron spectra for the neutron induced fission of 238U are calculated in the incident energy range where only the first fission chance is involved using the multi-modal fission theory. The partial spectra of each fission mode are calculated on the basis of Los Alamos model and the total spectrum is calculated by superposition of partial spectra weighted with the respective probability of occurrence. The total fission spectra obtained in this manner are in good agreement with the experimental data.