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Measurements of the Cherenkov effect in direct detection of charged particles with SiPMs.
Carnesecchi F., Sabiu B., Strazzi S., Vignola G., Agrawal N., Alici A., Antonioli P., Arcelli S., Bellini F., Cavazza D., Cifarelli L., Colocci M., Durando S., Ercolessi F., Ficorella A., Fraticelli C., Garbini M., Giacalone M., Gola A., Hatzifotiadou D., Jacazio N., Margotti A., Malfattore G., Nania R., Noferini F., Paternoster G., Pinazza O., Preghenella R., Rath R., Ricci R., Rignanese L., Rubini N., Scapparone E., Scioli G., Tripathy S., Zichichi A.
Silicon PhotoMultipliers (SiPMs) are established photon detectors of choice for a variety of applications because of their high efficiency, insensitivity to magnetic fields and low cost. SiPMs are usually coupled to scintillators or Cherenkov chambers. Recently it has been pointed out that SiPMs are also able to directly detect charged particles: indeed, at the passage of a single charged particle, several SPADs (Single Photon Avalanche Diodes), the SiPM unit microcell, are firing. This effect is related to Cherenkov light emission in the protection layer normally placed above the sensor as observed by comparing SiPMs with different, in thickness and material, protection layers and one SiPM without. Beam test results of SiPMs with resin protection layers feature an increased detection efficiency, if compared with a simple geometrical factor, reaching a value around 99%. Moreover, an intrinsic time resolution around 20 ps is measured. This result paves the way for moving SiPMs from simple photosensors to combined charged particles detectors. This possibility would open to applications of SiPMs in many areas, from space experiments to colliders detectors.