FIRST BEAM TESTS OF A FAST-RICH PROTOTYPE WITH VLSI READOUT ELECTRONICS

In this paper we briefly discuss the fast ring imaging Cherenkov detector technique that we have developed for application in proximity-focused geometry with solid crystal radiators (LiF, CaF2), and multiwire chamber photon detector using TEA in CH4 as a photosensor and cathode-pad readout. In particular, we describe the large-area full-scale Prototype of 12000 channels that we have constructed, along with associated technology such as the dedicated VLSI readout electronics that we have developed. We report the performance of the Prototype in a hadron test beam at the CERN PS. These tests give a Cherenkov angle resolution sigma(theta) = 13.8 mrad per photon, photoelectron yield N-pe(corr) = 11.20 pe/image, and momentum separation limit p(pi/K) (3 sigma) = 2.86 GeV/c for LiF radiator; and sigma(theta) = 17.0 mrad, N-pe(corr) = 9.88 pe/image, and p(pi/K) (3 sigma) = 2.39 GeV/c for CaF2 radiator. The system is well described by Monte Carlo simulations. Operation of the detector over several months has proven it to be reliable and robust. Preliminary test beam results taken with large-area CsI reflective photocathode detectors are also presented.