Novel photon detectors for RICH applications

The paper describes recent developments in Photon Detectors useful for the Ring Imaging Cherenkov (RICH) applications. We discuss the Multi-anode PMTs, Hybrid Photodiodes (HPDs) with PIN and Avalanche Photodiode (APD) readout, APDs working in a Geiger mode, and the gaseous multi-pattern detectors. The paper emphasizes their timing properties. We give equal chance to fragile, not yet entirely proven ideas.