TEMPERATURE STABILIZATION OF SiPM-BASED GAMMA-RADIATION SCINTILLATION DETECTORS

Abstract

Silicon photomultipliers (SiPMs) coupled with various scintillators are currently used as gammaradiation detectors for different applications. Many tasks require the ability to use detectors in environments with varying operating temperatures. However, the profound dependences of the characteristics of both SiPMs and scintillators on temperature make it difficult to use these detectors in such environmental conditions. The gain of an SiPM increases with increases in bias voltage, and it decreases with increases in temperature; however, the scintillator’s light yield may increase and/or decrease with temperature, depending on the type of scintillator used. Such temperature dependence makes it necessary to use special techniques for the stabilization of the detector parameters. We proposed and tested a method and an electronic module for compensating for the temperature instabilities of the gain of an SiPM and the light output of BGO and CsI(Tl) scintillators. Our method is based on the application of the SiPM biasing power supply that is controlled and managed by the microprocessor. The calibration data of the temperature dependence of a photo peak (662 keV) are stored in the microprocessor memory. The exact value of the bias voltage for each temperature is calculated by the formula of the 5th-degree polynomial. This method achieved a high accuracy of the photo peak position stabilization in the tested operation temperature range (-200C +500C). The test results of the SiPM-based gamma-radiation BGO and CsI(Tl) scintillation detectors as well as the results of their practical applications in medical surgical probes are presented.