Analysis of Test-Beam data from a prototype LHCb RICH detector

A prototype of the LHCb Ring Imaging Cherenkov detector has been constructed. The prototype module contained six pre-production pixel Hybrid Photon Detectors which were read out at the full LHC speed of 40 MHz using a prototype on-detector electronics readout system. The photon detectors were mounted in a gas vessel and Cherenkov rings were observed from an N2 gas radiator using electron and pion beams. The photoelectron yields and Cherenkov angle resolutions observed are in line with expectations.