Contribution Oral presentation
Long term experience and performance of COMPASS RICH-1
The RICH-1 Detector of the COMPASS Experiment at CERN SPS provides high quality hadron identification in the particle momentum range from 3 to 60 GeV/c, covering a wide angular acceptance and operating at high rates. It is in operation since 2002 and its performance increased thanks to progressive optimization and to a major upgrade of its photon detection system, implemented in 2006; a new upgrade is foreseen for 2016, using MPGD-based photon detectors. The main characteristics of COMPASS RICH-1 and the most critical problems encountered and presently faced are discussed together with the adopted solutions to guarantee radiator gas purity, mirror alignment control, stable photon detector response, heat removal and readout electronics optimization. The PID performance is presented and the observed evolution of the effective quantum efficiency of CsI photocathodes in gas photon detectors is discussed. The motivation and the plan for the future upgrade are briefly mentioned.