Gamma and neutron separation using emission wavelengths in Eu:LiCaI scintillators

TL;DR

This paper introduces a novel wavelength-based method for distinguishing neutrons from gamma rays in Eu-doped LiCaI scintillators, enhancing particle identification without waveform analysis.

Contribution

It presents the first demonstration of using emission wavelength differences for particle discrimination in scintillators, offering a new approach for radiation detection.

Findings

Different radiation particles produce distinct emission wavelength signatures.

The method successfully separates neutron and gamma signals using wavelength information.

Experimental results confirm particle dependence of emission wavelengths in Eu:LiCaI scintillators.

Abstract

Scintillators have long been known as radiation detectors and are still used in various applications. Recently, scintillators containing $^6$Li have been developed as neutron detectors and have attracted attention. $^6$Li absorbs thermal neutrons and emits $\alpha$+$^3$H, which is promising as a neutron detector if it can be separated from background gamma rays. We have been developing Eu:LiI-CaI$_2$-based scintillators (Eu:LiCaI) for this purpose. In scintillator detectors, waveform information is generally used to distinguish particles such as neutrons and gamma rays. We propose a new particle identification method using emission wavelengths information. In this study, experiments were conducted using Eu:LiCaI crystals, multi-pixel photon counter optical sensors, and long-wavelength cut filters to verify the proposed method. The results of irradiating a $^{252}$Cf neutron source and a $^{60}$Co gamma-ray source indicate that there is a particle dependence of the output signal ratio between with and without filters. This means that different types of radiation particles have different emission wavelengths. This is the first demonstration of a wavelength-based particle identification method.