Influence of Self-Absorption on Pulse Shape Discrimination in Organic Glass Scintillators

TL;DR

This study examines how light self-absorption affects pulse shape discrimination in organic glass scintillators, revealing size-dependent performance impacts and optimizing discrimination methods.

Contribution

It provides new insights into the influence of self-absorption on pulse shape discrimination and employs genetic algorithms to analyze scintillator decay components.

Findings

Light self-absorption reduces photoelectron yield and Figure of Merit with increasing scintillator size.

Normalized Figure of Merit remains constant despite size changes.

Genetic algorithms effectively estimate decay times and intensities of scintillator light pulses.

Abstract

Organic glass scintillators are an interesting alternative to liquid scintillators, offering many advantageous characteristics with few drawbacks. In this paper we investigate the influence of light self-absorption in the organic glass scintillator on its pulse shape discrimination capability. With five scintillators of different heights but same diameter, we measure photoelectron yield and Figure of Merit in neutron-gamma discrimination. The decrease of both values with increasing size is attributed to light self-absorption, while normalized Figure of Merit remains constant. The choice of gates for charge comparison method is discussed. We also use genetic algorithm to estimate decay times and intensities of fast, medium, and slow components of light pulse shapes measured with Bollinger-Thomas setup. We compare the results to trans-stilbene reference sample.