Exploring Large-Volume GAGG Scintillators for use in MeV Gamma-Ray Astrophysics

TL;DR

This paper explores the use of large-volume GAGG scintillators as calorimeters for MeV gamma-ray astrophysics, demonstrating their potential for future high-energy gamma-ray telescopes through experimental testing and characterization.

Contribution

It introduces a new large-volume GAGG scintillator array for gamma-ray detection and provides experimental results on its performance across different energies and crystal configurations.

Findings

Successful development of a 5x5 GAGG array calorimeter

Effective detection of gamma rays from 2 to 25 MeV

Characterization of crystal response based on surface treatment

Abstract

Gamma-ray astrophysics in the MeV band is an exciting field in astronomy due to its potential for multi-messenger astrophysics. It has, however, remained under-explored when compared to other wavelengths. One reason for this observational gap is the difficulties with measuring these high-energy photons and the requirement of large amounts of detection material. In this work, we investigate the usage of large-volume GAGG scintillators for use as a calorimeter in future MeV telescopes. We developed a $5\times5$ array calorimeter utilizing $1\times1\times6 \ \mathrm{cm}^3$ GAGG crystals with onsemi C-series SiPM readout. We tested the calorimeter at the High Intensity Gamma-ray Facility (HIGS) with monoenergetic beams ranging from $2-25 \ \mathrm{MeV}$. Finally, we also investigate larger $1\times1\times8 \ \mathrm{cm}^3$ crystals and characterize their response across their depth when their surface treatment is either polished or frosted.