Optical Detector with Integrated ADC for Digital Readout

Many nuclear physics experiments use photomultiplier tubes (PMTs) coupled to scintillators, which require a readout using BNC cables, HV cables, HV suppliers, analog-to-digital converters (ADCs), and possibly additional modular electronics and mainframes for signal processing. These items tend to account for a significant amount of the cost per detector channel, which limits the size of the experiment and the number of detector channels. A novel method for signal digitization is required to reduce these costs. This project will investigate the use of a CMOS solid-state photomultiplier (SSPM), integrated with an on-chip ADC, as a cost effective method for digitizing the photodetector signal. Phase I showed that a detector designed with large-area solid-state photomultiplier can provide energy resolution equivalent to that of a traditional photomultiplier tube, but at a fraction of the cost. Phase II will develop a large area (~1 cm x 1 cm) device with on-chip signal processing and integrated digitization. The work will provide the required schematics, processes, and mask sets for full production of these devices, so that they can be implemented for nuclear physics experiments. Commercial Applications and other Benefits as described by the awardee: These devices should find use in a variety of experiments as a viable alternative to the traditional method for scintillator readout. Furthermore, a standardized design for an SSPM with integrated ADC would provide a functional platform for a myriad of low-cost, compact products for gamma-ray spectroscopy, flow cytometry, neutron detection, dosimetry, and even nuclear imaging applications, such as PET and SPECT