Spectrum of Prompt Fission Neutrons from 235U(n, F)

A new matrix of the spectra of prompt fission neutrons for the reaction 235 U(n, F) has been obtained. The evaluated spectrum of prompt fission neutrons reproduces the measured data for incident neutrons with energy from thermal to 14.7 MeV. A solution is proposed for the problem of inconsistency of the integral testing of the systems with a thermal spectrum and differential measurements of the spectra of prompt fission neutrons. The matrix obtained for the spectra of prompt neutrons for 235 U(n, F) eliminates the considerable discrepancy between the differential and integral experiments. The description of the integral experiments for compositions with a fast neutron spectrum revealed the compensation effect in the multiplication factor K eff , due to the difference in the shapes of the spectra of prompt fission neutrons, the present work and known libraries. The description of systems with a thermal neutron spectrum shows that the positive shift of the computed K eff is explained by the influence of the low-energy neutrons.