Study of Silicon Photomultipliers in Low Earth Orbit

The LabOSat collaboration aims to increase the Technology Readiness Level of electronic devices and components for space-borne applications in Low Earth Orbits. Since 2014, the collaboration has tested different electronic components in space environments using different versions of its flagship testing platform: LabOSat-01. Some of the electronic components tested in the past include resistive switching memories and dosimeters based on field-effect transistors. A daughter board was developed for LabOSat-01, which was used to characterize four ONSEMI MicroFC-60035-SMT Silicon Photomultipliers in DC mode. Each Silicon Photomultiplier was enclosed in a light-tight aluminum housing along with an LED to test it under controlled illumination.In this Proceeding, we report the results obtained after 2 and a half years (958 days) of measurements of Silicon Photomultiplier performance in Low Earth Orbit. The temperature range of the electronics and sensors was −7 °C to 4 °C. The DC-DC boost converters used to bias the Silicon Photomultipliers remained operational at the set bias voltage of 29.1 V. An increase of expected Silicon Photomultiplier current under various LED illuminations was observed and these values increased with mission time. Several hypotheses are under evaluation, like gradual damage to the electronics, to the light-tight housings, or both.