Status and perspectives of vacuum-based photon detectors

Vacuum-based photodetectors are one of the most promising devices to detect Cherenkov photons. This paper reviews recent developments of vacuum-based photodetectors, such as multi-anode photomultiplier tubes (MaPMTs), hybrid photodetectors (HPDs/HPADs) and micro-channel-plate PMTs (MCP-PMTs), in view of application to RICH detectors. Photodetectors with luminescent anode are also discussed. It is emphasized that, in the past several years, there has been significant progress in development of devices having improved quantum efficiency, immunity for the magnetic field, and timing resolution.