SiPM-Based Detector for High-Resolution Measurements in Pulsed Radiation Fields

Abstract

Modern ionizing radiation generators used for medical imaging and radiotherapy operate in the pulsed regime or have short exposure times. This classifies them as pulsed sources. Electronic dosimeters that measure dosimetric quantities, the ambient dose equivalent [ $H^\ast $ (10)], and the personal dose equivalent [ $H_{\mathrm {p}}$ (10)] that show satisfactory performance in pulsed fields are emerging, but the accuracy of $H^\ast $ (10) rate (d $H^\ast $ (10)/ $\text{d}t$ ) measurements of short pulses is lagging behind. With the goal of solving this problem, we developed a novel system for measurements of $H^\ast $ (10) and $H^\ast $ (10) rate in pulsed fields. The measurement chain is composed of a thallium-doped sodium iodide scintillation crystal optically coupled to a silicon photomultiplier, an amplifier, and a high memory depth digital storage oscilloscope. To investigate the detector performance, a series of measurements in a pulsed radiation field was made for in-beam and scattered radiation. Both the $H^\ast $ (10) and $H^\ast $ (10) rates were successfully measured with 1-ms time resolution, while the best-achieved resolution was 1 and 10 nSv/h, respectively. The analysis of the $H^\ast $ (10) rate response showed that the detector measurement range is from natural background radiation levels (~100 nSv/h) up to 250 mSv/h.