Electrical breakdown in Thick-GEM based WELL detectors

The occurrence of electrical discharges in gas detectors restricts their dynamic range and degrades their performance. Among the different methods developed to mitigate discharge effects, the use of resistive materials in the detector assembly was found to be very effective. In this work, we present the results of a comparative study of electrical discharges in Thick-GEM-based WELL-type detectors - with and without resistive elements. We present a new method to measure discharges in the resistive-detector configurations; it allows demonstrating, for the first time, the occurrence of discharges also in the Resistive-Plate WELL detector configuration. It also provides direct evidence for the Raether limit.