Abstract
RICH counters for PID in the high momentum domain and in large acceptance experiments require photon detectors covering extended surface of several square meters and able to accept Cherenkov photons in a wide angular range. An ideal approach is represented by gaseous photon detectors, which allow covering wide surfaces at affordable costs.
Novel gaseous photon detectors using closed geometry, as those possible with multistage arrangements of micropattern gaseous detectors, can overcome the limitations observed in present gaseous photon detectors with solid CA photocathode, which are due to the ion bombardment of the photocathode. We have started an R&D programme to develop a Thick GEM-based photon detector and we report about the status of this project.