Performance of H2GCROC3, the readout ASIC of SiPMs for the back hadronic sections of the CMS High Granularity Calorimeter

Abstract

H2GCROC is a 130 nm CMOS ASIC designed to read out the SiPMs coupled to the scintillating tiles of the back hadronic sections of CMS HGCAL. Each of its 72 channels comprises a current conveyor, a high-gain preamplifier, a shaper, an ADC for energy measurement, and two discriminators linked to TDCs for capturing time-of-arrival and time-over-threshold information, respectively. This work presents the ASIC architecture and its characterization in the laboratory and test beam environments. The results demonstrate its adaptability in calibration, proving its capability to measure the SiPM single-photon spectrum and MIP's energy with high resolution under the expected radiation conditions during the entire operation of HGCAL.