Production, Quality Control and Performance of GE1/1 Detectors for the CMS Upgrade

The Large Hadron Collider (LHC) will be upgraded in several phases that will allow significant expansion of its physics program. After the long shutdown in 2019 (LS2) the accelerator luminosity will be increased to 2-3 ×1034 cm−2s−1 for Run 3 and later up to 5×1034 cm−2s−1 for Phase 2 (HL-LHC). The physics program of the LHC experiments will benefit from the augmented luminosity; the sensitivity of the CMS experiment to new physics and to the Standard Model will be fully exploited, providing that a suitable upgrade will enable the CMS detector to cope with future data-taking conditions. Among the upgrades, the installation of new muon stations based on Gas Electron Multiplier (GEM) technology in the endcap will start in early 2019 (GE1/1 station), followed by the installation of two additional stations (GE2/1 and ME0) in 2023. The CMS Muon Collaboration produced the 144 GEM detectors to be installed in the GE1/1 station, sharing the assembly and testing of the detectors among several production sites spread all over the world. A detailed common assembly protocol and quality control procedure (QC) has been deployed, with the ambitious goal to ensure standardization of the performance of the detectors produced by the different sites. The same procedure has been successfully adopted to test the first prototypes of the GE2/1 detectors. In this contribution, we present the final results of the QC tests performed on the GE1/1 chambers, assembled by all the production sites following the common specification parameters.