Development of a THGEM-based photon detector for Rich applications

THGEMs (T Hick Ge Ms) are electron multipliers derived from the Gem design, with scaled geometrical parameters and manufactured using standard PCB production technology. Coupled to Cesium Iodide photo converting layer they are promising candidates as detectors for future Cherenkov Imaging Counters. More than 30 THGEMs, different in geometry and production processes, have been characterized in order to optimize their performance for Rich applications. The photoelectron extraction and collection efficiencies have been studied for several gas mixtures. Encouraging results have also been obtained from the tests with multilayer THGEMs used either for ionizing particles of UV light detection. This paper presents the recent developments of these studies.