Design validation of the CMS Phase-2 Triple-GEM detectors

Abstract

The High-Luminosity LHC will deliverproton-proton collisions at 5.0–7.5 times the nominal LHC luminosity, with anexpected number of 140–200 pp-interactions per bunch crossing. To maintain the performance of muon triggering and reconstruction underhigh background, the forward part of the Muon spectrometer of the CMSexperiment will be upgraded with Gas Electron Multipliers (GEM) and improvedResistive Plate Chambers detectors. Particularly challenging isthe extension of the pseudorapidity of the muon system up to |η| < 2.8with a 6-layer station, named ME0, that will be installed behind the newhigh granularity calorimeter and that will see particle rates up to150 kHz/cm2 and integrate a dose of 250 krad by the end of the High Luminosity phase of the LHC.In this contribution we will present the major design changes of the Triple-GEMdetectors to adapt them for the harsh radiation environment and the highparticle rate. We shall summarize the performance of prototype Triple-GEMdetectors measured with X-rays and gamma at theCERN GIF++ irradiation facility.