Radiation measurements using solid-state Photomultipliers: Gammas, charged particles, and neutrons

Counting individual scintillation pulses produced by radiation provides excellent sensitivity for dosimeter applications, however, the light pulse produced by the scintillation material has previously needed the high gain of a PMT to read out the signal. The recent development of solid-state photomultipliers provides the high gain, high-bandwidth performance needed to implement event counting with the scintillation detector. The CMOS SSPM detector is a compact, rugged, low-power photodetector that is well suited for scintillation-based applications. The digital representation of scintillator photon multiplicity provides a convenient basis for digital radiation measurements. Traditional tissue equivalent scintillation materials provide a direct measure of the energy deposited and the dose equivalent and are a good match for charged-particle dosimetry, as they typically produce relatively small light pulses for gamma ray events. In addition, new scintillation materials are being developed that detect neutrons and can implement pulse shape discrimination to reject interfering gamma ray signals on an event-by-event basis. This work presents preliminary evaluations of three types of radiation detectors constructed from an SSPM. An LYSO scintillator gamma-ray dosimeter, a charged-particle detector using tissue-equivalent plastic scintillator for space dosimetry, and a neutron detector made from boron-loaded plastic are demonstrated..