TESTS OF RICH PHOTON DETECTORS FOR THE HERA-B EXPERIMENT

A multiwire proportional chamber with CsI photocathode pads and a TMAE based photon detector have been tested in order to evaluate their pot ential as candidates for a fast ring imaging Cherenkov counter, to be used for separation of pions from kaons in the HERA-B experiment propo sed at DESY. Results of the tests are presented and the following para meters are discussed: the number of photons detected per ring, resolut ion of the Cherenkov angle, photoelectron drift time distribution, fra ction of clusters and avalanche photon feedback.