CALIBRATION OF 122 SENSL MICROFJ-60035 SIPMS AND THE REDUCTION OF OPTICAL CROSS-TALK DUE TO COUPLED LIGHT GUIDES

The excellent production quality of recent generations of Silicon Photomultipliers (SiPMs) allows for operation without individual calibration of the breakdown voltage. Measurements of the crosstalk probability and the relative gain of 122 SiPMs of type SensL MicroFJ-60035-TSV are presented. Semi-conductor photo sensors have replaced photo multiplier tubes in numerous applications featuring single-photon resolution, insensitivity to magnetic fields, higher robustness and enhanced photo detection efficiency at lower operation voltage and lower costs. Light guides are used to increase the comparably small photo sensitive area of SiPMs. Their optical coupling changes the surface conditions of the sensor and influences the probability for crosstalk photons to leave the sensor without inducing secondary breakdowns. This study compares properties of sensors that are optically coupled to light guides with bare sensors, operated at nominal bias voltage. It demonstrates, that the optical coupling to a light guide significantly reduces the crosstalk probability of the measured sensors.