Prompt fission neutron multiplicity and spectra evaluation in the frame of the multi-modal fission model for 237Np(n,f) and 238U(n,f)

The multi-modal fission model approach was used for the evaluation of the prompt fission neutron multiplicity and spectra for the neutron induced fission of 237Np and 238U. The model parameters are based on experimental data obtained at IRMM. The three most dominant fission modes (standard I, standard II and superlong) are taken into account. For each fission mode the prompt neutron multiplicity and spectrum are calculated within an improved version of the Los Alamos model. The calculated total prompt neutron multiplicity and spectrum are in good agreement with the experimental data. Also, the average prompt gamma ray energy for each fission mode is obtained as well as the total prompt gamma ray energy. The total prompt gamma ray energy for 237Np(n, f) is in agreement with existing experimental data