PARISROC, a photomultiplier array readout chip

PARISROC is a complete read out chip, in AMS SiGe 0.35 micron technology, for photomultipliers array. It is a front-end electronics ASIC which allows triggerless acquisition for the next generation of neutrino experiments. These detectors have place in megaton size water tanks and will require very large surface of photo-detection. An R & D program, funded by French national agency for research and called PMm2, proposes to segment the very large surface of photo-detection in macro pixels made of 16 photomultiplier tubes connected to an autonomous front-end electronics. The ASIC allows triggerless acquisition and only send out the relevant data by network to the central data storage. This data management reduces considerably the cost of these detectors. This paper describes the front-end electronics ASIC called PARISROC which integrates totally independents 16 channels with a variable gain and provides charge and time measurement with a 12-bit ADC and a 24-bits Counter.