Quality Control and certification of GEM detectors for the CMS GE2/1 station

The Compact Muon Solenoid (CMS) experiment at CERN’s most powerful particle accelerator, the Large Hadron Collider (LHC), is a detector where proton-proton collision events are observed and studied by particle physicists. The undergoing upgrades of the LHC will increase the instantaneous luminosity up to L = 5 × 1034cm−2 s −1 , and therefore the experiments will need further developments as well. The CMS GEM Collaboration is working on upgrading the muon end-caps with the installation of Gas Electron Multipliers (GEM) detectors such as their second ongoing project, the GE2/1 chambers. GE2/1 will be the second station in the forward region of the muon end-caps in CMS installed by the end of 2023 and beginning of next year. The main goal of the muon system upgrade is to maintain the Level 1 trigger rate with maximum selection efficiency. The GEM technology is very useful in High-Energy Physics experiments. The triple-layer gaseous detectors with their microscopic structures are capable to provide the needed detection properties required by the CMS experiment for such an upgrade. This report focuses on the qualification tests done for the validation of GE2/1 detector for installation in CMS.