App note from ON Semiconductors about SiPM sensors, explaining the working principle and primary performance parameters. Link here (PDF)
The Silicon Photomultiplier (SiPM) is a sensor that addresses the challenge of sensing, timing and quantifying low-light signals down to the single-photon level. Traditionally the province of the Photomultiplier Tube (PMT), the Silicon Photomultiplier now offers a highly attractive alternative that combines the low-light detection capabilities of the PMT while offering all the benefits of a solid-state sensor. The SiPM features low-voltage operation, insensitivity to magnetic fields, mechanical robustness and excellent uniformity of response. Due to these traits, the SensL® SiPM has rapidly gained a proven performance in the fields of medical imaging, hazard and threat detection, biophotonics, high energy physics and LiDAR.