A Gamma-Ray Imaging Detector Using Position-Sensitive SiPM Coupled to GAGG:Ce Scintillator Array

Position-sensitive scintillator detectors are critical components in coded-aperture imaging and Compton imaging systems. Improving the position resolution and energy resolution of the detector is crucial for system performance. Traditional position sensitive scintillator detectors are constrained by the size of photoelectric readout devices and the number of readout channels, making it difficult to achieve both high position resolution and energy resolution at a low cost. This study presents a novel gamma-ray imaging detector that overcomes the traditional trade-off between position resolution, energy resolution, and cost. Using a high-resolution cerium-doped gadolinium aluminum gallium garnet (GAGG:Ce) scintillator array ( $0.5\times 0.5\times 5$ mm pixels) read out by a position-sensitive silicon photomultiplier (PS-SiPM) through its four anodes, we achieved direct position reconstruction without the use of a light-sharing technique. A ¹³⁷Cs source was used to test the performance of this imaging detector. It demonstrated a clear segmentation of a $10\times 10$ array with 7.2% [full-width-at-half-maximum (FWHM)] energy resolution for 662 keV, significantly simplifying the design of electronic readout systems.