Geiger-mode avalanche photodiodes for Cherenkov detectors

Semiconductor photo sensors have in comparison with other detectors used in the ring image Cherenkov (RICH) and in the internally reflected Cherenkov light (DIRC) technique, photomultipier tubes and their derivates, a number of advantages: they have high photon detection efficiency (similar to 50%), are insensitive to magnetic fields, operate at low voltages and allow a compact, light and robust design. Specially the relatively new Geiger-mode avalanche photodiode (also called silicon photomultiplier) is a promising candidate for a detector of Cherenkov photons. The state of the development and the problems of this device will be described.