Feasibility assessment of an SiPM for implementation in an OSL reader

Abstract

In this work, we report on the feasibility of a silicon photomultiplier (SiPM) for optically stimulated luminescence dosimeter (OSLD) application. In particular, to assess SiPMs as a viable technology for OSLD, we investigated the SiPM response to OSL detection in terms of microcell size, excess voltage (Vex), and photon threshold-levels. Furthermore, the dose response was explored to highlight some of the benefits and limitations of relying on SiPMs in OSL detection compared to using the conventional reader based on photomultiplier tubes (PMTs). SiPMs tested in this work were based on the Hamamatsu S13360-series with the pixel area of 3 × 3 mm2 and microcell pitches of 25μm, 50μm, and 75μm. The material used for the OSL detection is based on Al2O3:C and the measurements were carried out using a Risø TL/OSL reader system with the existing PMT replaced with a customized SiPM readout module. The results showed that SiPMs exhibit optimal performances at Vex of 5 V, 3 V, and 3 V for 25μm, 50μm, and 75μm, respectively. We also demonstrated that the dose responses in three SiPMs are nearly linear for doses below 1 Gy and found the minimal detectable doses as 23 mGy, 20 mGy, and 11 mGy for 25μm, 50μm, and 75μm, respectively. Finally, it was shown that the detection sensitivity in the OSL signal fluctuates by nearly 5% for a temperature change of about 0.5 °C in an SiPM.