CATIROC, a Multichannel Front-End ASIC to Read Out the 3″ PMTs (SPMT) System of the JUNO Experiment

The ASIC CATIROC (Charge And Time Integrated Read Out Chip) is a complete read-out chip designed to read arrays of 16 photomultipliers(PMTs). It finds a valuable application in the content of the JUNO ( Jiangmen Underground Neutrino Observatory) experiment [1], a liquid scintillator antineutrino detector with a double calorimetry system combining about 17k 20″ PMTs (Large PMTs system) and around 25k 3″ PMTs (Small PMTs system). A front-end electronics based on the ASIC CATIROC matches well within the 3″ PMTs system specifications as explained in this paper. CATIROC is a SoC (System on Chip) that processes analog signalsup to the digitization to reduce the cost and cables number. The ASIC is composed of 16 independent channels that work in triggerless mode, auto-triggering on the single photo-electron (PE). It provides a charge measurement with a charge resolution of 15 fC and a timing information with a precision of 200 ps rms.