Investigating the Thickness-Dependent Scintillator-PMT Interface Reflection Coefficients with GAGG:Ce³⁺ Crystals Using the Dual-PMT Setup

Ken and Mary Alice Lindquist Department of Nuclear Engineering The Pennsylvania State University

^* ful51@psu.edu

Published online: 21 November 2023

Abstract

Recently, it has been shown through both Monte Carlo simulations and experiments that scintillator-PMT interface reflection coefficients could depend on crystal thickness. It has been argued that the thickness-dependency on the interface reflection coefficient is a result of bulk attenuation and surface reflections. So far, only LYSO:Ce³⁺ scintillators have been tested to investigate thickness-dependent reflection coefficients. In this work, the simulations and experiments are extended to GAGG:Ce³⁺ crystals. Moreover, a new experimental technique (the dualPMT setup) has been tested to measure the interface reflection coefficients, and it has been shown through the dual-PMT setup that GAGG:Ce³⁺-PMT interface reflection coefficients are thickness-dependent with more than 1σ confidence. These results are also supported with extensive Monte Carlo simulations.