Comparison of two solid-state photomultiplier-based scintillation gamma-ray detector configurations

Adequate monitoring and tracking of radiation at department of energy legacy sites requires deployment of highly sensitive detectors. Utilizing the high sensitivity of inorganic scintillation materials usually requires a photomultiplier tube, which increases the cost, size, and power consumption of the detector. A gamma-ray detector consisting of a CMOS-based solid-state photomultiplier (SSPM), which offers low power consumption and a very small form factor, coupled to a variety of scintillation materials has been developed. We have compared the sensitivity of the CMOS SSPM radiation meter with regard to source identification and overall sensitivity as a function of incident gamma-ray energy. Two prototype configurations are compared with respect to homeland security applications: an SSPM spectrometer, with a high resolution scintillation material and many channels of readout, and a low resolution rate-meter with only four channels of energy information. Each device utilizes a 3 mm times 3 mm SSPM with 2024 pixels coupled to a scintillator matched to the size of the SSPM.