A Cherenkov beam counter for ultra-relativistic heavy-ion experiments

Abstract

A beam counter system consisting of two sets of gas Cherenkov counters was constructed for ultra-relativistic heavy-ion experiments. The performance has been examined with sulphur ions of 200 GeV/ c per nucleon. The intrinsic time resolution and the width of the pulse height distribution are 30 ps and 5%, respectively, at a beam intensity of 2×10 6 ions/s. The detector was successfully operated for more than one month, although some reduction in pulse height was observed as a long-term variation.