Low-energy neutron cross-talk between organic scintillator detectors

TL;DR

This study characterizes neutron cross-talk between organic scintillator detectors using measurements and simulations across various energies and angles, revealing good spectral agreement but some discrepancies in cross-talk probabilities.

Contribution

It provides new experimental data and Monte Carlo simulation validation for low-energy neutron cross-talk in organic scintillators, highlighting areas for model improvement.

Findings

Monte Carlo simulations agree well with time-of-flight spectra.

Cross-talk probabilities are approximately matched, with notable discrepancies at low energies.

Neutron interaction processes causing cross-talk are analyzed in detail.

Abstract

A series of measurements have been performed with low-energy monoenergetic neutrons to characterise cross-talk between two organic scintillator detectors. Cross-talk time-of-flight spectra and probabilities were determined for neutron energies from 1.4 to 15.5 MeV and effective scattering angles ranging from $\sim$50{\deg} to $\sim$100{\deg}. Monte-Carlo simulations incorporating both the active and inactive materials making up the detectors showed reasonable agreement with the measurements. Whilst the time-of-flight spectra were very well reproduced, the cross-talk probabilities were only in approximate agreement with the measurements, with the most significant discrepancies ($\sim$40 %) occurring at the lowest energies. The neutron interaction processes producing cross-talk at the energies explored here are discussed in the light of these results.