New front-end electronics for INO-ICAL experiment

The India-based Neutrino Observatory (INO) is an underground experimental facility housing high energy and nuclear physics experiments. A 50 kton magnetized Iron Calorimeter (ICAL) detector is the flagship experiment at this facility. The primary goal of ICAL experiment is to determine the neutrino mass ordering using atmospheric neutrino events. The detector will consist of 151 alternating layers of iron and Resistive Plate Chambers (RPCs). The iron will provide the active target for the atmospheric neutrinos to interact, whereas the RPCs will help in detecting muons and hadrons produced from such interactions. The signal produced due to the muon interaction with the active gas medium in the detector will be extracted using a two-dimensional readout of the RPCs. The complete ICAL detector will have approximately 3 million channels to be readout. Such a large number of channels require an efficient, robust and cost-effective readout system. A semi-digital readout system HARDROC2 has been tested and commissioned to its possible use for ICAL experiment. The HARDROC2 chip is fabricated using 350 nm SiGe technology and characterized by 64 channel readouts with low power consumption. In this paper, we propose a new front-end electronics based on HARDROC2 ASIC for the ICAL experiment. We report the results obtained from a detailed study performed to optimize the various performance parameters like channel calibration and uniformity using the test bench setup. We also provide the efficiency and cluster size results obtained for ICAL RPC detectors with HARDROC2 based readout and compares the same with the one obtained with custom electronics.