HKROC: an integrated readout chip designed to facilitate the readout of a large number of photomultiplier tubes for the next generation of neutrino experiments

The HKROC ASIC was designed to read out Photo-Multiplier Tubes (PMTs) for next-generation neutrino experiments. These experiments are increasing in scale, with a larger number of PMTs and, consequently, a greater number of read-out channels. A highly integrated read-out system is required to facilitate construction while also meeting stringent requirements for noise, speed, and dynamic range. The HKROC ASIC was designed with 36 channels to measure the Time of Arrival (ToA) and the charge of the input signal. Working as a waveform digitizer, it measures the ToA with a resolution of 200 ps (at 1 photon-electron i.e. 1 p.e.) and the charge with a linearity of around 1% across a dynamic range of up to 1250 p.e. In this paper, we will describe the HKROC architecture, the motivation behind two successive prototypes, and the latest measurements.