SiPM-based detector for high resolution measurements in pulsed radiation fields: preliminary findings

Ten years ago, it became evident that commercially available dose and dose rate meters do not measure correctly in pulsed radiation fields. Pulsed fields have become mainstream technology in medical imaging and they are present in nondestructive testing, accelerators, etc. Today, some modern dosimeters perform better with only a slight underestimation in pulsed fields of higher dose rates, but dose rate measurements during the pulse still remain a challenge, especially for scattered radiation. This can also be extended to short exposures, dominant in the medical sector. We developed a detector consisting of a silicon photomultiplier coupled to a 10x10x10 mm ³ scintillator. For the current stage of research, a NaI(Tl) scintillation crystal was chosen due to its high light yield and capability to detect low energy X-rays. Signals from the detector are digitized using a digital storage oscilloscope and recorded for offline analysis. Analysis was based on signal integration, which remained invariant to pulse pileup and thus allowed measurements from low to high dose rates several times higher than IEC 61526 requirements. Preliminary results showed sufficient time and dose (H*(10)) resolution for measurement of scattered radiation pulses down to several ms in width.