Active control of the gain of a 3 mm x 3 mm Silicon Photomultiplier

Solid-state photodetectors working in the Geiger mode—known as Silicon PhotoMultipliers (SiPM) or MultiPixel Photon Counters (MPPC)—are currently being developed with increasingly large active areas. Potential applications for low-light-level detection were investigated with a MPPC, recently made available by Hamamatsu. The device was optically coupled with a scintillator and its performances, in terms of single photoelectron discrimination, were studied in a series of measurements under different operating conditions. An active control of the gain was implemented by a linear feedback on the operating voltage. The results of the tests are discussed.