Analysis of the total kinetic energy of fission fragments with the Langevin equation

TL;DR

This study uses three-dimensional Langevin calculations to analyze the total kinetic energy of fission fragments across various actinides, revealing systematic trends and the impact of different transport coefficients on energy distribution.

Contribution

It introduces a detailed Langevin-based approach to systematically study TKE in fission, comparing microscopic and macroscopic transport coefficients and their effects.

Findings

TKE decreases with increasing excitation energy.

Microscopic transport coefficients align better with experimental data.

Different fission modes contribute to mass-energy distributions.

Abstract

We analyzed the total kinetic energy (TKE) of fission fragments with three-dimensional Langevin calculations for a series of actinides and Fm isotopes at various excitation energies. This allowed us to establish systematic trends of TKE with $Z^2/A^{1/3}$ of the fissioning system and as a function of excitation energy. In the mass-energy distributions of fission fragments we see the contributions from the standard, super-long, and super-short (in the case of $^{258}$Fm) fission modes. For the fission fragments mass distribution of $^{258}$Fm we obtained a single peak mass distribution. The decomposition of TKE into the prescission kinetic energy and Coulomb repulsion showed that decrease of TKE with growing excitation energy is accompanied by a decrease of prescission kinetic energy. It was also found that transport coefficients (friction and inertia tensors) calculated by a microscopic model and by macroscopic models give drastically different behavior of TKE as a function of excitation energy. The results obtained with microscopic transport coefficients are much closer to experimental data than those calculated with macroscopic ones.