Radiation-hard digital analog silicon photomultipliers for future upgrades of Ring Imaging Cherenkov detectors

Two of the leading experiments in the field of experimental particle physics are the LHCb spectrometer, which detects particles produced by high-energy collisions at the LHC accelerator, and the Belle II spectrometer, which operates at the SuperKEKB accelerator. Of key importance to both experiments is the precise identification of the resulting particles, for which Ring Cherenkov (RICH) detectors are used. Accelerator upgrades planned over the course of this decade will greatly increase the luminosity, and thus both the rate of detection of true events and the level of ionizing radiation to which the detectors will be exposed. Therefore, it will also be necessary to upgrade some subdetector systems of the spectrometers. Such upgrades of the RICH detectors will require photodetectors that will be able to efficiently detect single photons with high spatial and timing resolution, and retain such abilities over several years of operation despite exposure to high levels of radiation. The combination of all these requirements is not met by any of the currently available photodetectors, so dedicated technology development is required. Silicon photomultipliers (SiPMs) are a relatively new light sensor, with excellent performance but insufficient tolerance to radiation. In this project, we propose the development of SiPMs that will meet all of the requirements of next-generation RICH detectors, including radiation hardness. This will be achieved by developing and integrating dedicated electronics, and combining several radiation hard techniques in the design of SiPMs.