Evaluation of SiPM-based readout system with gain stabilization for TL dosimetry

Abstract

As the silicon photomultiplier (SiPM) technology has developed and matured, it has opened up avenues for its use in various luminescence dosimetry applications. However, the temperature sensitivity of SiPMs needs to be considered in settings where a SiPM-driven system may be affected by heat, such as during thermoluminescence (TL) measurements. This study investigated the TL signal reproducibility and temperature dependence of SiPMs (3×3mm2,50μm) using a Risoe TL/OSL-DA-20 reader, a gain stabilizing driver circuit, and a data acquisition (DAQ) module. The signal variation was insignificant when the temperature varied by less than 2 °C. However, when there was no temperature control, the signal loss occurred due to increased dark counts. We assessed four commercial dosimeters and compared them to conventional TL detection via a photomultiplier tube (PMT) in terms of dose-response, detection limits, and TL glow-curve characteristics. The slope in the dose-response (i.e., sensitivity) of the SiPM-based system was 1.5 to 3 times lower compared to PMT depending on the dosimeter. We explored the viability of TL readings by examining the potential reduction in sensitivity and dark counts due to the SiPM's photon-resolving feature. While the evaluation results of the suggested system demonstrate its practical usefulness, there are still unexplored areas that warrant further investigation. These are discussed in relation to the dark count rate, which is a major parameter that can impede the overall performance.