Gamma-ray response of a GAGG:Ce scintillator coupled to a 2 × 2 SiPM array

Abstract

A relatively large 35 × 35 × 20 mm3 GAGG:Ce scintillator coupled to a 2 × 2 silicon photomultiplier (SiPM) array was characterized for gamma-ray detection, including relative-gain calibration, nonlinear energy response, energy resolution, and timing resolution. The SiPM-array response was well described by a saturation-inspired nonlinear calibration function. For the gain-calibrated individual-readout configuration, energy resolutions of 5.31(9)% at 1173.2 keV and 5.05(8)% at 1332.5 keV were obtained, while offline-simulated summed readout yielded comparable values. Coincidence measurements using 60Co yielded single-detector timing resolutions of σ = 429(9) ps for individual readout and σ = 425(9) ps for hardware-summed readout. Sensitivity to low-energy gamma rays was also demonstrated by detecting the 59.5-keV line from 24Am. These results provide a useful performance reference for compact gamma-ray detector designs based on relatively large GAGG:Ce crystals and SiPM-array readout.