An overview of the design, construction and performance of large area triple-GEM prototypes for future upgrades of the CMS forward muon system

Abstract

GEM detectors are used in high energy physics experiments given their good spatial resolution, high rate capability and radiation hardness.An international collaboration is investigatingthe possibility of covering the 1.6 < |η| < 2.4 region of the CMS muon endcaps with large-areatriple-GEM detectors. The CMS high-η area is actually not fully instrumented, only Cathode Strip Chamber (CSC) are installed. The vacant area presents an opportunity for a detector technology able to to cope with the harsh radiation environment; these micropattern gas detectors are an appealing option to simultaneously enhance muon tracking and triggering capabilities in a future upgrade of the CMS detector. A general overview of this feasibility study is presented. Design and construction of small (10cm × 10cm) and full-sizetrapezoidal (1m × 0.5m) triple-GEM prototypes is described. Results from measurementswith x-rays and from test beam campaigns at the CERN SPS is shown for the small andlarge prototypes. Preliminary simulation studies on the expected muon reconstruction andtrigger performances of this proposed upgraded muon system are reported.