Performance of the silica aerogel cherenkov detector used in the European hybrid spectrometer

Abstract The performance of an 18 module silica aerogel Cherenkov detector, with a total sensitive surface of 2.3 m 2 , situated in the European Hybrid Spectrometer at the CERN SPS, is described. The light yield for β = 1 particles is on the average 7.5±0.3 photoelectrons. Particle identification with this detector is discussed. Fi3st results on the ageing effects of silica aerogel are presented.