Energy dependence of fission product yields in ²³⁵U（n, f ） within the Langevin approach incorporated with the statistical model

【摘要】 In this study, Langevin approach incorporated with the statistical model is adopted to investigate independent fission yields for a large quantity of fission products and the dependence of prompt fission observables on the incident neutron energy in 235U（n, f）. The neutron evaporation from the fission process is considered by coupling the Weisskopf statistical model to Langevin dynamical simulation, where the potential energy surface of the respective fissioning nucleus from each fission chance is calculated using the macroscopic-microscopic model within the two-center shell model. The partitions of the charge and total excitation energy between the two complementary fragments are evaluated such that the prompt neutron emissions from fission fragments can be described based on the characteristics of primary fragments. With the present model, the calculated independent fission yields of the isotopes from Z = 30-61 in 14 MeV n+ ²³⁵U fission are in good agreement with the evaluated data from ENDF/BVⅢ.0. Moreover, the evolution of the independent mass yields and the cumulative yields for select isotopes with the incident neutron energy, as well as the tendency of both the average TKE and prompt neutron multiplicity with the increase in the incident neutron energy, are consistent with the experimental data. The present model can aid in reproducing prompt fission observables across a range of incident neutron energies for major actinides.更多还原

【Abstract】 In this study, Langevin approach incorporated with the statistical model is adopted to investigate independent fission yields for a large quantity of fission products and the dependence of prompt fission observables on the incident neutron energy in 235U（n, f）. The neutron evaporation from the fission process is considered by coupling the Weisskopf statistical model to Langevin dynamical simulation, where the potential energy surface of the respective fissioning nucleus from each fission chance is calculated using the macroscopic-microscopic model within the two-center shell model. The partitions of the charge and total excitation energy between the two complementary fragments are evaluated such that the prompt neutron emissions from fission fragments can be described based on the characteristics of primary fragments. With the present model, the calculated independent fission yields of the isotopes from Z = 30-61 in 14 MeV n+ ²³⁵U fission are in good agreement with the evaluated data from ENDF/BVⅢ.0. Moreover, the evolution of the independent mass yields and the cumulative yields for select isotopes with the incident neutron energy, as well as the tendency of both the average TKE and prompt neutron multiplicity with the increase in the incident neutron energy, are consistent with the experimental data. The present model can aid in reproducing prompt fission observables across a range of incident neutron energies for major actinides.更多还原