Beam tests of a Fast-RICH prototype with VLSI readout electronics

In this report we discuss the Fast Ring Imaging Cherenkov technique that we have developed for application to proximity-focused LiF (or CaF₂) solid radiator and multiwire chamber photon detector with cathode-pad readout using TEA in CH₄ as photosensor. We describe the full-scale Prototype of 12 000 pads (5.334 × 6.604 mm²) we have built, and briefly the dedicated VLSI readout electronics we have developed. We report in detail the investigations we have performed in a hadron test beam at the CERN PS, and compare the results obtained to the expected performances. The maximum momentum for π/K separation at 3σ achieved in these tests is 2.86 GeV/c for LiF (2.39 GeV/c for CaF₂). The experimentally achieved Cherenkov merit factors, after correction for azimuthal angle acceptance, are N₀ = 65.5 cm⁻¹ (57.7 cm⁻¹), to be compared with 53.8 cm⁻¹ (50.2 cm⁻¹) from Monte Carlo calculations. Operation of the detector over several months has proven the technique reliable and robust, and suitable for application in high-luminosity hadron colliders like LHC, as well as e⁺e⁻ B-Factories like KEK (Japan), SLAC (USA), and Cornell (USA).