Performance studies of MicroMegas for the ATLAS experiment

Abstract

The performance of MicroMegas (MM) has been extensively studied during several test beam campaigns with high energy particle beams at CERN up to the year 2012, and more recently (June 2013) with electron beams at DESY. Main objectives of the tests were to demonstrate that the requirements could be achieved for the upgrade of the ATLAS Muon Spectrometer, where the MicroMegas will be mounted (along with small-strip Thin Gap Chambers - sTGC) on the New Small Wheel for forward muon detection. The MM layout and operating settings have then been chosen to satisfy the ATLAS upgrade requirements and trigger timing constraints. Results for efficiencies, time resolution and spatial resolution for perpendicular and inclined tracks are presented. Moreover, in ATLAS the MM will operate in a non-uniform magnetic field up to 0.3 T. Dedicated test beam measurements have been carried out in a variable magnetic field between 0 and 1 T. The performance of MM in magnetic fields is also reported along with a comparison to simulations.© CERN 2014 for the benefit of the ATLAS collaboration.