Neutron-induced fission: properties of prompt neutron and γ rays as a function of incident energy

Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico, 87545, USA

^a e-mail: stetcu@lanl.gov

Published online: 21 June 2016

Abstract

We have applied the Hauser-Feshbach statistical theory, in a Monte-Carlo implementation, to the de-excitation of fission fragments, obtaining a reasonable description of the characteristics of neutrons and gamma rays emitted before beta decays toward stability. Originally implemented for the spontaneous fission of ²⁵²Cf and the neutroninduced fission of ²³⁵U and ²³⁹Pu at thermal neutron energy, in this contribution we discuss the extension of the formalism to incident neutron energies up to 20 MeV. For the emission of pre-fission neutrons, at incident energies beyond second-chance fission, we take into account both the pre-equilibrium and statistical pre-fission components. Phenomenological parameterizations of mass, charge and TKE yields are used to obtain the initial conditions for the fission fragments that subsequently decay via neutron and emissions. We illustrate this approach for ²³⁹Pu(n,f).