Effects of Neutron Emission on Fragment Mass and Kinetic Energy Distribution from Thermal Neutron-Induced Fission of $^{235}U$

TL;DR

This study uses Monte-Carlo simulations to analyze how neutron emission affects the mass and kinetic energy distributions of fragments from thermal neutron-induced fission of uranium-235, revealing new insights into the distribution broadening.

Contribution

The paper introduces a simulation approach that explains the broadening in fragment distributions due to neutron emission, highlighting its impact on interpreting experimental data.

Findings

Reproduces broadening in kinetic energy distribution at specific fragment masses

Identifies neutron emission as a key factor affecting distribution shapes

Shows that neutron emission complicates the inference of primary fragment properties

Abstract

The mass and kinetic energy distribution of nuclear fragments from thermal neutron-induced fission of 235U have been studied using a Monte-Carlo simulation. Besides reproducing the pronounced broadening in the standard deviation of the kinetic energy at the final fragment mass number around m = 109, our simulation also produces a second broadening around m = 125. These results are in good agreement with the experimental data obtained by Belhafaf et al. and other results on yield of mass. We conclude that the obtained results are a consequence of the characteristics of the neutron emission, the sharp variation in the primary fragment kinetic energy and mass yield curves. We show that because neutron emission is hazardous to make any conclusion on primary quantities distribution of fragments from experimental results on final quantities distributions.