Sensitivity of measured fission yields on prompt-neutron corrections

TL;DR

This paper examines how assumptions about prompt-neutron emissions affect measured fission yields, highlighting the importance of understanding -dependent neutron emission for accurate nuclear data analysis.

Contribution

It investigates the impact of mass-dependent prompt-neutron emission assumptions on fission yield measurements and emphasizes the need for experimental determination of (n) dependence.

Findings

Mass-dependent (n) assumptions significantly alter measured yields.

Post-neutron emission mass distributions can change by 10-30%.

Current data libraries may be affected by outdated neutron emission assumptions.

Abstract

The amount of emitted prompt neutrons from the fission fragments increases as a function of excitation energy. Yet it is not fully understood whether the increase in \nu(A) as a function of E_{n} is mass dependent. The share of excitation energies among the fragments is still under debate, but there are reasons to believe that the excess in neutron emission originates only from the heavy fragments, leaving \nu_{light}(A) almost unchanged. In this work we investigated the consequences of a mass-dependent increase in \nu(A) on the final mass and energy distributions. The assumptions on \nu(A) are essential when analysing measurements based on the 2E-technique. This choice showed to be significant on the measured observables. For example, the post-neutron emission mass yield distribution revealed changes up to 10-30%. The outcome of this work pinpoint the urgent need to determine \nu(A) experimentally, and in particular, how \nu(A) changes as a function of incident-neutron energy. Until then, many fission yields in the data libraries could be largely affected, since they were analysed based on another assumption on the neutron emission.