Performance and calibration of a 2 m$^2$ SM2 micromegas detector for the ATLAS muon spectrometer upgrade

The steadily increasing luminosity of LHC requires an upgrade to high rate capability and high resolution detector technologies, for the innermost station of the muon spectrometer of the ATLAS experiment. For precision tracking 4 types of 2 and 3 m$^2$ large Micromegas quadruplets will provide 8 consecutive active layers, each with 100 μ m spatial resolution per individual plane. Data taken at the 120 GeV SPS muon and pion beam in August 2017 on one 2 m$^2$ quadruplet prototype (SM2 built by the German colleagues). The full active area of the SM2 prototype quadruplet has been calibrated in the Munich Cosmic Ray Facility (CRF).