Characterization of CMOS Solid-State Photomultiplier for a Digital Radiation Rate Meter

An approach to detect the light from scintillation materials using an array of small photon counting detectors, referred to as a "solid-state photomultiplier" (SSPM), detects light from a scintillation material to provide a sensitive radiation monitor. Each pixel acts as a binary photon detector, but the summed output is an analog representation of the total photon intensity, which is proportional to the energy of the gamma ray. We have successfully fabricated arrays of GPD pixels in a CMOS environment, which makes possible the production of miniaturized arrays integrated with the detector electronics in a small silicon chip. This detector technology allows for a substantial cost reduction while preserving the energy resolution needed for radiological measurements. In this work, we demonstrate the operation of a 100-pixel array in reading an LSO scintillation crystal. In addition, we present the energy spectra corrected for saturation effects and examine the effects of cross talk on the performance of the SSPM.