Angular distribution of fragments in neutron-induced nuclear fission at energies 1−200 MeV: Data, theoretical models and relevant problems

Abstract

In recent years, investigations of angular distributions of fragments in neutron-induced nuclear fission have been extended to intermediate energies, up to 200 MeV, as well as to a wide range of target isotopes. Using as an example the latest data obtained by our group for the reaction 237Np(n; f), we discuss the specific features of fission fragment angular distribution and present a method for their simulation based on the code TALYS. It is shown that a simplified model reasonably describes energy dependence of the angular distribution in the whole range 1–200 MeV. The ways to improve the model are discussed along with the possibilities to use it for obtaining new information on fission and pre-equilibrium processes in neutron-nucleus interaction. We consider also the relevant problems of describing fission fragment angular distributions.

Measurement of the $^{236}$U fission cross section and angular distributions of fragments from fission of $^{235}$U and $^{236}$U in neutron energy range of 0.3-500 MeV

“…In the first case the reactions 232 Th(n, f ) and 238 U(n, f ) at energies of incident neutrons up to 100 MeV were considered. Our analysis was devoted to the reactions 237 Np(n, f ) [29,56,57] and 240 Pu(n, f ) [30] for neutrons with energies up to 200-300 MeV. This kind of analysis cannot be performed using publicly available programs such as TALYS, since they (at least those known to us) lack the option to calculate the angular distributions of fragments.…”