Neutron response of PARIS phoswich detector

TL;DR

This study investigates the neutron detection efficiency of the PARIS phoswich detector, combining experimental measurements and simulations to evaluate its performance for high-energy gamma-ray detection.

Contribution

It provides the first detailed analysis of neutron response in the PARIS phoswich detector using TOF, PSD, and GEANT4 simulations, demonstrating effective neutron-gamma separation at relevant energies.

Findings

Approximately 95% of neutrons with E_n > 3 MeV interact primarily in LaBr3(Ce) crystal.

The detector achieves clear neutron-gamma separation at a 15 cm flight path.

Experimental results agree well with GEANT4 simulations.

Abstract

We have studied neutron response of PARIS phoswich [LaBr$_3$(Ce)-NaI(Tl)] detector which is being developed for measuring the high energy (E$_{\gamma}$ = 5 - 30 MeV) $\gamma$ rays emitted from the decay of highly collective states in atomic nuclei. The relative neutron detection efficiency of LaBr$_3$(Ce) and NaI(Tl) crystal of the phoswich detector has been measured using the time-of-flight (TOF) and pulse shape discrimination (PSD) technique in the energy range of E$_n$ = 1 - 9 MeV and compared with the GEANT4 based simulations. It has been found that for E$_n$ $>$ 3 MeV, $\sim$ 95 \% of neutrons have the primary interaction in the LaBr$_3$(Ce) crystal, indicating that a clear n-$\gamma$ separation can be achieved even at $\sim$15 cm flight path.