Kinetic energy of fission fragments within a dynamical model

TL;DR

This paper models the kinetic energy of individual fission fragments in actinide nuclei using a dynamical approach, successfully reproducing experimental trends and analyzing contributions like pre-scission energy.

Contribution

It introduces a detailed dynamical model to calculate the kinetic energy of each fission fragment, a focus less explored in prior total-energy studies.

Findings

Reproduces experimental kinetic energy trends for light and heavy fragments.

Finds pre-scission kinetic energy contributes about 2-4%.

Analyzes fission of $^{239}$Pu and $^{258}$Fm with good agreement.

Abstract

Kinetic energy of individual fission fragment for actinide nuclei is, for example, important for evaluating the prompt-neutron spectrum in the laboratory system. It is experimentally known that kinetic energy for each fragment is constant at about 100 MeV for light fragments and that for heavy fragments decreases linearly with mass number. Most of the theoretical studies carried out so far attempted to calculate the total kinetic energy of both fragments, i.e. sum of the energies of two fragments, but the kinetic energy of each fragment was not analyzed in detail as far as we recognize. We have calculated them in thermal-neutron induced fission of $^{239}\mathrm{Pu}$ with a dynamical model using Langevin equations within a three-dimensional two-center parametrization. Also fission of $^{258}\mathrm{Fm}$ was investigated. It is calculated from the Coulomb energy at the scission point and the pre-scission kinetic energy. It is found that the pre-scission kinetic energy has about 2-4% contribution in the kinetic energy. The calculated results reproduce the trend of the experimental data.