Front-end electronics based on an autonomous, trigger-less ASIC for LHAASO

The Large High Altitude Air Shower Observatory (LHAASO) is designed to search for cosmic-ray sources by the measurement of gamma rays up to 1 PeV, to survey the whole northern sky for gamma-ray sources above 300 GeV, and to study cosmic-ray physics from 10 TeV to a few hundreds of PeVs. The LHAASO observatory will be located at high altitude (4300m in the Yunnan province, China) and will include different detectors with known techniques, each of them being optimized for one of these goals. The LHAASO detectors have typically high channel density and require very low power consumption due to poor power dissipation at high altitude. The front-end electronics based on ASIC application matches well such specifications. The PARISROC chip (Photomultiplier ARray Integrated in SiGe ReadOut Chip) is a 16-channel ASIC with channels that work independently, in triggerless mode and all managed by a common digital part. It is currently being adapted to the WFCTA (Wide Field of View Cherenkov Telescope Array) detectors of LHAASO. In this paper, the characterization of PARISROC chip and the obtained performances will be presented.