THE EVAPORATION MODEL THEORY FOR THE FISSION PROMPT NEUTRON SPECTRUM OF HEAVY NUCLEI

Abstract：

The fission prompt neutron spectrum,the average number of neutrons emitted per fission and the average energies of neutrons for neutron-induced fission of ura-nium and plutonium isotopes were calculated,using evaporation model with a univer-sal pre-scission neutron component of about 10% added empirically.General appro-ximation formulae for the average number of neutrons per fisson and the averageneutron energy were derived and Terrell's formula was rederived theoretically without adjustable constants.In the incident neutron energy range 0—18 MeV considered,the agreement between calculated and experimental results is satisfactory.NUCLEAR FISSION:U,Pu(n,f);energy range 0—18 MeV;fission prompt neutron spectrum,average number of emittedneutrons and neutron average energy calculated.