Modelling instrumental response for neutron scattering experiments at CSNS

TL;DR

This paper develops a data reduction method to accurately model the instrumental response in neutron scattering experiments at CSNS, ensuring consistency between simulations and measurements for thermal neutron scattering on water.

Contribution

It introduces a novel data reduction technique for processing detector data, improving the accuracy of neutron scattering simulations and analysis.

Findings

High agreement between simulated and experimental detector responses

Accurate reproduction of inelastic scattering signatures in simulations

Demonstration of inelastic scattering effects elimination in models

Abstract

Thermal neutron total scattering experiments of light and heavy water were reproduced using the CSNS in-house Monte Carlo thermal neutron transport code, Prompt, with a focus on the instrumental detector response and the accurate derivation of thermal neutron scattering cross-sections. In this work, a data reduction method is developed to process both the measured and simulated detector events for estimating angular, wavelength distributions, as well as angular differential cross sections. The reduction results of simulations and experiments show a high degree of consistency. The prominent inelasticity signatures observed in the experiments can be accurately reproduced in simulations. We discuss the cause of the inelasticity effects, and demonstrate the elimination of such effects when the inelastic scattering process is taken into account in simulations. In addition, multiple scattering in samples is analysed and discussed.