Characterization study of a new UV-SiPM with low dark count rate

SiPM-based detectors are foreseen as good candidates for low light level detection applications requiring timing resolution in the few hundreds of picoseconds range. We report here the development of a UV enhanced SiPM with low dark count rate particularly well suited for high energy physics and medical imaging. In order to address different applications, we have produced a range of 1, 3, and 5 mm SiPMs with 25, 50, and 100 μm micro-cells size (1600, 400, and 100 micro-cells) with geometrical efficiencies ranging from 21% to 79%. Our highest geometrical efficiency 1 mm SiPM has reached a PDE of 40% in photon counting mode at 440 nm and a dark count rate as low as 200 kcps/mm2 at 25 °C and an overvoltage of 3%. To our knowledge this is the lowest dark count rate under above conditions reported so far. Breakdown voltage is in the 130-150 V range, quench resistance is in the order of 1.5 MΩ, while the chip capacitance is of the order of 10 pF/mm2. All characteristics from this novel low dark count SiPM design will be presented and compared, further developments and improvements will also be discussed.