A $16\times8$ Digital-SiPM Array With Distributed Trigger Generator for Low SNR Particle Tracking

This letter describes a 16 × 8-pixel array based on single-photon avalanche diodes (SPADs) optimized for the readout of a tracking detector based on plastic scintillation fibers targeting ultrafast neutrons. Each pixel of 125 × 250 μm
²
size contains 30 SPADs, an 80-ps 10-b time-to-digital converter (TDC), a 5-b intensity counter, a finite state machine (FSM) that manages the recording of data and a three-word-deep FIFO memory for parallel acquisition and readout, achieving 32.1% pixel fill factor. A combined, programmable current-based local, and global triggering mechanism correlates the photon detection activity in time to distinguish asynchronous charged particle trace events from background noise even with a poor SNR.