방사선의학 웹진

바로가기  >

Abstract
The employment of silicon photomultipliers (SiPMs) in photon detection systems facilitates the reduction of detection module size, enhances portability and ruggedness, and lowers product costs. This study investigated the potential of SiPM in thermoluminescence (TL) measurements, focusing on its detection limits, temperature dependency, and dose responses. A 3 × 3 mm2 multi-pixel photon counter (MPPC, Hamamatsu MPPC) composed of 50 μm single-photon avalanche diodes (SPADs) was utilized in single-photon counting mode as the detector. This experimental setup was compared with a conventional photomultiplier tube (PMT) in TL readout case. To ensure comparable light exposure between the two detectors, a 3-mm diameter pinhole was positioned in front of the PMT. By using a thermoelectric (TE) cooling module to maintain the sensor temperature at −20 °C, signal reproducibility was achieved with a fluctuation of less than 1.2%, and a detection limit ranging from 30 to 300 μGy was assessed for four dosimeters: LiF:Mg,Ti, LiF:Mg,Cu,P, LiF:Mg,Cu,Si, and Al2O3:C. The dose response of the system was limited by significant signal saturation due to pile-up effects. We introduced a correction model with a 50 ns paralyzable deadtime, which enhanced the signal response by more than 20-fold. Furthermore, this model also correlated well with the observed count rates under high dark count rate (DCR) conditions up to 1.67 MHz. The findings from this study further contributes to the discussion regarding the perspective of SiPM as TL detectors.

Hyoungtaek Kim a, Jisung Hwang b c, Kyung Taek Lim d

a
Korea Atomic Energy Research Institute, Daejeon, Republic of Korea
b
Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea
c
Korea Institute of Nuclear Safety, Daejeon, Republic of Korea
d
Dept. of Quantum and Nuclear Engineering, Sejong University, Republic of Korea