Discharge studies with single- and multi-GEM structures

The demands of a new generation of experiments in hadron physics require a substantial further advancement of gaseous detectors. Novel devices must handle the high luminosities planned for future hadron and electron colliders as well as meet the requirements of large experiments such as the substantial increase in active detector area. Among the new innovative detector techniques, the Gas Electron Multiplier (GEM) has become a widely used technology for high-rate experiments and is also foreseen for future large-area detectors (e.g. ALICE, CMS, sPHENIX). The key parameters for a long-term operation of GEM-based detectors in the harsh environment of high-rate experiments are radiation hardness, ageing resistance and stability against electrical discharges. Therefore, a comprehensive understanding of the discharge mechanism is mandatory to assure a stable operation of the detector. We report on discharge probability studies in single- and multi-GEM structures in Ar- and Ne-based gas mixtures. Our experimental findings are compared to the outcome of the GEANT simulations. This research was supported by the DFG cluster of excellence ''Origin and Structure of the Universe''.