Optimization of the digital Silicon Photomultiplier for Cherenkov light detection

Abstract

The Silicon Photomultiplier is a promising alternative to fast vacuum photodetectors. We developed a fully digital implementation of the Silicon Photomultiplier. The sensor is based on a single photon avalanche photodiode (SPAD) integrated in a standard CMOS process. Photons are detected directly by sensing the voltage at the SPAD anode using a dedicated cell electronics block next to each diode. This block also contains active quenching and recharge circuits as well as a one bit memory for the selective inhibit of detector cells. A balanced trigger network is used to propagate the trigger signal from all cells to the integrated time-to-digital converter. Photons are detected and counted as digital signals, thus making the sensor less susceptible to temperature variations and electronic noise.The integration with CMOS logic has the added benefit of low power consumption and possible integration of data post-processingin the sensor. In this paper, we discuss the sensor architecture together with its characteristics, and its possible optimizations for applications requiring the detection of Cherenkov light.