Discharge Investigation in GEM Detectors in the CMS Experiment

The Endcap Muon detectors in the CMS experiment are GEM detectors which are known to have occasional discharges between layers of the detector. A less known phenomenon is a double discharge which is a second discharge initiated by the primary discharge in the following transfer gap. The probability of the double discharge was measured as a function of the electric field of the following transfer gap and found that the probability transitions from 0-100\% when the field strength is between 7-10 kV/cm. An experimental setup is ready to be used to understand the physics and cause behind double discharges, and as a means to test electronics for their resistance to discharges.