Abstract: A single photon radiation detector is designed for a particular radiation source fluence, such that an incident radiation photon strikes a scintillator monolith, creating scintillation photons, which are amplified by appropriately sized channels of photomultipliers optically coupled to the scintillator monolith. The photomultiplier output is electronically shaped into a corresponding stream of scintillation pulses (otherwise referred to as scintillation photons) that pass through a comparator to produce a bitstream of the detected scintillation photons, which is sampled into a field programmable gate array (FPGA) acting as a giga-sample transceiver to produce time-to-digital conversions, capable of producing an output data stream of 10's-of-giga-samples per second or more. Appropriate design ensures sparsity of scintillation photon arrival, so that each photon in the bitstream corresponds to a single incident scintillation photon.

Abstract: This disclosure provides systems, methods, and apparatus related to semiconductor photomultipliers. In one aspect, a device includes a p-type semiconductor substrate, the p-type semiconductor substrate having a first side and a second side, the first side of the p-type semiconductor substrate defining a recess, and the second side of the p-type semiconductor substrate being doped with n-type ions. A conductive material is disposed in the recess. A p-type epitaxial layer is disposed on the second side of the p-type semiconductor substrate. The p-type epitaxial layer includes a first region proximate the p-type semiconductor substrate, the first region being implanted with p-type ions at a higher doping level than the p-type epitaxial layer, and a second region disposed on the first region, the second region being doped with p-type ions at a higher doping level than the first region.