The high voltage system the novel MPGD-based photon detectors of COMPASS RICH-1 and its development towards a scalable HVPSS for MPGDs

Abstract

The COMPASS RICH-1 detector underwent major upgrade in 2016 with the installation of four novel MPGD-based photon detectors. They consist of large-size hybrid MPGDs with multi-layer architecture composed of two layers of Thick-GEMs and bulk resistive Micromegas. A dedicated high voltage power supply system, realized with commercial devices, has been put in operation to protect the detectors against errors by the operator, monitor and log voltages and currents at a 1 Hz rate, and automatically react to detector misbehavior; it includes also the HV compensation for the detector gas pressure and temperature variations.The needs posed to the high voltage power supply systems by the operation of Micro Pattern Gaseous Detectors pushed the development of a novel single channel HV system able to overcome the performance of the commercial devices in terms of high-resolution diagnostic features and intelligent dynamic voltage control. In this talk the COMPASS HV system and its performance are illustrated, as well as the stability of the novel MPGD-based photon detectors during the physics data taking at COMPASS. The performance of the novel single channel power supply system when connected to a single photon Micro Pattern Gaseous Detector is presented in realistic working condition during a test beam with the preliminary results of multiple channels operation.