MeV Neutron Production from Thermal Neutron Capture in {6}^Li Simulated with Geant4

TL;DR

This study evaluates Geant4's accuracy in simulating fast neutron production from thermal neutron capture in lithium-6 compounds, finding good agreement with measurements and supporting its use in neutron background assessments.

Contribution

The paper assesses Geant4's performance in modeling fast neutron emission from lithium-6, highlighting its suitability for neutron background evaluation at spallation sources.

Findings

Geant4 simulations agree well with experimental data.

Simulations effectively model neutron background for neutron facilities.

Supports use of Geant4 in neutron instrument background analysis.

Abstract

Various Li compounds are commonly used at neutron facilities as neutron absorbers. These compounds provide one of the highest ratios of neutron attenuation to $\gamma$-ray production. Unfortunately, the usage of these compounds can also give rise to fast neutron emission with energies up to almost 16 MeV. Historically, some details in this fast neutron production mechanism can be absent from some modeling packages under some optimization scenarios. In this work, we tested Geant4 to assess the performance of this simulation toolkit for the fast neutron generation mechanism. We compare the results of simulations performed with Geant4 to available measurements. The outcome of our study shows that results of the Geant4 simulations are in good agreement with the available measurements for $^6$Li fast neutron production, and suitable for neutron instrument background evaluation at spallation neutron sources.