s . in s - de t ] 1 9 O ct 2 00 1 Performance of the triple - GEM detector with optimized 2 - D readout in high intensity hadron beam

Performance of the triple-GEM detector with optimized 2-D readout in high intensity hadron beam. Abstract Multiple-GEM detectors are considered to be good candidates for tracking devices in experiments with high hadronic background. We present the results of the triple-GEM detectors beam test in a high intensity pion beam. The detectors had an optimized two-dimensional readout with minimized strip capacitance. Such optimization permitted the starting point of the efficiency plateau down to a gain of 5000. The probability of GEM discharges induced by heavily ionizing particles has been measured as a function of gain: at a gain of 20000 it amounts to 10 −11 per incident particle. Such a value will ensure safe operation of the detector in the conditions of forward region of the LHC experiments.