Status report on the CMS forward muon upgrade with large-size triple-GEM detectors

Abstract

For the LHC High Luminosity phase (HL-LHC) the CMS GEM Collaboration is planning to install new large size (990 x 440-220 mm2) triple-GEM detectors, equipped with a new readout system, in the forward region of the muon system (1.5 lt II lt 2.2) of the CMS detector. Combining triggering and tracking functionalities the new triple-Gas Electron Multiplier (GEM) chambers will not only improve the performance of the CMS muon trigger, but will also improve the muon identification and track reconstruction. With the addition of triple-GEM detectors the forward region of the CMS muon spectrometer will recover its originally planned redundancy. Starting from 2009 the CMS GEM Collaboration built several small and full size prototypes with different geometries, keeping improving the assembly techniques. All these prototypes have been tested in laboratories as well as with beam tests at the CERN SPS and at Fermilab. The results show that the triple-GEM detectors are a mature technology satisfying all the requirements to be used in the forward region of the CMS muon system at HL-LHC. In this contribution we will report on the status of the CMS upgrade project with GEMs and its impact on the CMS performance as also the hardware architectures and expected performance of the CMS GEM readout system. Abstract-For the High-Luminosity LHC (HL-LHC) phase the CMS GEM Collaboration is planning to install new largesize (990 × 220-455 mm 2 ) triple-GEM detectors, equipped with a new readout system, in the forward region of the muon system (1.5 < |η| < 2.2) of the CMS detector. Combining triggering and tracking functionalities the new triple-foil Gas Electron Multiplier (GEM) chambers will improve both the performance of the CMS muon trigger and the muon reconstruction/identification in CMS experiment. The addition of triple-GEM chambers to the forward region of the CMS muon system will add a necessary layer of redundancy. Starting from 2009 the CMS GEM Collaboration has built several small and full-size prototypes with different geometries, keeping improving the assembly techniques. All these prototypes have been tested in laboratories as well as with beam tests at the CERN Super Proton Synchrotron (SPS) and at Fermi National Accelerator Laboratory. In this contribution we will report on the status of the CMS upgrade project with triple-GEM chambers and its impact on the CMS performance as well as the hardware architectures and expected capability of the CMS GEM readout system.