A RICH detector with two-stage gas amplification at atmospheric pressure

Abstract

A prototype of a Ring Imaging Cherenkov detector (RICH) with two-stage gas amplification has been developed. The detector consists of a time projection chamber (TPC) with a sensitive volume of 19×20×6 cm 3 followed by a parallel plate avalanche counter (sensitive volume 20×5×0.4 cm 3) and a multiwire proportional chamber (MWPC) with 96 wires 2 mm apart. The gas used was an argon/methane/isobutane mixture (ratio 60/20/20) at atmospheric pressure. TMAE at 15°C served as the photosensitive component. The measurements were done with a calibrated VUV photon source. The following results were obtained: spatial resolution of the MWPC 1.2 mm, spatial resolution of the TPC 800 μm, attachment length (13.0±1.6) cm and photon detection efficiency 4.2% corresponding to N 0 = 25 cm −1