Material Properties of Popular Radiation Detection Scintillator Crystals for Optical Physics Transport Modeling in Geant4

Abstract

Radiation detection is vital for space, medical imaging, homeland security, and environmental monitoring applications. In the past, the Monte Carlo radiation transport toolkit, Geant4, has been employed to enable the effective development of emerging technologies in these fields. Radiation detectors utilizing scintillator crystals have benefited from Geant4; however, Geant4 optical physics parameters for scintillator crystal modeling are sparse. This work outlines scintillator properties for GAGG:Ce, CLLBC:Ce, BGO, NaI:Tl, and CsI:Tl. These properties were implemented in a detailed silicon photomultiplier (SiPM)-based single-volume scintillation detector simulation platform developed in this work. It was validated by its comparison to experimental measurements. For all five scintillation materials, the platform successfully predicted the spectral features for selected gamma-ray emitting isotopes with energies between 30 keV and 2 MeV. The full-width at half-maximum (FWHM) and normalized cross correlation coefficient (NCCC) between simulated and experimental energy spectra were also compared. The majority of simulated FWHM values reproduced the experimental results within a 2% difference, and the majority of NCCC values demonstrated agreement between the simulated and experimental energy spectra. Discrepancies in these figures of merit were attributed to detector signal-processing electronics modeling and geometry approximations within the detector and surrounding experimental environment.