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

The COMPASS RICH-1 detector underwent major upgrade in 2016 with the installation of fournovel MPGD-based photon detectors. They consist of large-size hybrid MPGDs with multi-layerarchitecture composed of two layers of Thick-GEMs and bulk resistive Micromegas. A dedicated highvoltage power supply system, realized with commercial devices, has been put in operation toprotect 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 forthe detector gas pressure and temperature variations.The needs posed to the high voltagepower supply systems by the operation of Micro Pattern Gaseous Detectors pushed the development ofa novel single channel HV system able to overcome the performance of the commercial devices interms of high-resolution diagnostic features and intelligent dynamic voltage control. In this talkthe COMPASS HV system and its performance are illustrated, as well as the stability of the novelMPGD-based photon detectors during the physics data taking at COMPASS. The performance of thenovel single channel power supply system when connected to a single photon Micro Pattern GaseousDetector is presented in realistic working condition during a test beam with the preliminaryresults of multiple channels operation.