Advances in triple-GEM detector operation for high-rate particle triggering

Abstract We report the results of a systematic study of the time performance of triple-GEM detectors operated with several gas mixtures which are new for this kind of detectors. We show that a considerable improvement, with respect to the traditional gas mixture Ar/CO 2 (70/30), is obtained with the fast and high yield based CF 4 and iso-C 4 H 10 gas mixtures; time resolutions better than 5 ns. Discharge studies have been performed with high intensity π/proton beams at the Paul Sherrer Institute (PSI). The results show that the operation of the detector is very stable, if a small fraction of iso-C 4 H 10 or a large amount of CF 4 , is use.