Investigation of consistency and temperature compensation in SiPM-coupled GAGG scintillator linear arrays

Silicon photomultipliers (SiPMs) have been widely employed in radiation detection due to their compact size and excellent photon detection efficiency. However, inconsistencies such as gain variation, dark count rate differences, and bias voltage non-uniformity among multiple SiPM channels remain significant challenges in practical applications. In this study, Onsemi MicroFC-30035 SiPMs, each with an active area of 3 × 3 mm², were employed. Two types of cerium-doped gadolinium aluminum gallium garnet (GAGG) scintillators fabricated by distinct methods—Czochralski crystal growth and ceramic sintering—were coupled to form linear arrays. By precisely tuning the bias voltage of each SiPM pixel via a low-dropout regulator (LDO) module, gain non-uniformity in linear array A was reduced from 7.06 % to 0.42 %, significantly enhancing the energy spectrum uniformity. Temperature correction models were established based on polynomial regression of energy spectra over the range of 0 °C–40 °C, reducing the peak position variation from 20.96 % to 2.03 % for linear array A, and from 29.28 % to 1.08 % for linear array B, thereby effectively mitigating temperature-induced spectral drift. This study reveals the critical impact of scintillator fabrication methods on temperature stability and demonstrates a practical calibration approach combining fine-grained bias adjustment and temperature compensation. The findings provide valuable references for improving performance and stability in SiPM-based gamma-ray imaging systems, with potential applications in nuclear medicine, industrial non-destructive testing, and security inspection.