# Energy dependence of fission-fragment neutron multiplicity in $^{235}\textrm{U}(n,f)$

## TL;DR

This paper presents a comprehensive theoretical framework to analyze how the number of neutrons emitted during fission varies with energy in uranium-235, incorporating shape evolution, energy sharing, and microscopic level densities.

## Contribution

It introduces a novel, consistent model combining shape evolution, statistical energy division, and microscopic level densities to predict neutron multiplicities in fission.

## Key findings

- The model accurately predicts neutron multiplicities across different energies.
- Deformation energies significantly influence neutron emission.
- The approach enhances understanding of energy dependence in fission processes.

## Abstract

A consistent framework for treating the energy dependence of fission-fragment neutron multiplicities is presented. The shape evolution of the compound nucleus towards scission is treated in the strong damping limit using the Metropolis walk method. The available excitation energy at scission is then divided statistically between the two fragments using microscopic level densities. Deformation energies, which contribute to the excitation energy when the fragments relax to their ground-state shapes, are also computed. From the total fragment excitation energies, the number of emitted neutrons is obtained and illustrated for neutron-induced fission of $^{235}\textrm{U}$.