Single photon detection with SiPMs irradiated up to 10$^{14}$ cm$^{-2}$ 1-MeV-equivalent neutron fluence

Understand

Silicon photomultipliers (SiPM) are solid state light detectors with sensitivity to single photons.

• Their use in high energy physics experiments, and in particular in ring imaging Cherenkov (RICH) detectors, is hindered by their poor tolerance to radiation.
• At room temperature the large increase in dark count rate makes single photon detection practically impossible already at 10$^{11}$ cm$^{-2}$ 1-MeV-equivalent neutron fluence.
• The neutron fluences foreseen by many subdetectors to be operated at the high luminosity LHC range up to 10$^{14}$ cm$^{-2}$ 1-MeV-equivalent.