Particle discrimination in medium energy physics with an aerogel Cherenkov detector

Abstract A new threshold Cherenkov detector to discriminate pions from kaons in the momentum range from 1.2 GeV/ c to 1.73 GeV/ c is discussed. Silica aerogel is used as radiator. A method for developing such detectors by the aid of Monte Carlo simulations is presented. A rejection rate for π + of 99.8±0.2% has been reached. The production of fast secondary electrons by subthreshold particles is considered.