Performance studies of a micromegas chamber in the ATLAS environment

Five small prototype micromegas detectors were positioned in the ATLAS detector during Large Hadron Collider running at ?s = 7 and 8?TeV. A 9 ? 4.5?cm2 double drift gap detector was placed in front of the electromagnetic calorimeter and four 9 ? 10?cm2 detectors on the ATLAS Small Wheel, the first station of the forward muon spectrometer. The one attached to the calorimeter was exposed to interaction rates of about 70?kHz/cm2 at = 5 ? 1033?cm?2s?1 two orders of magnitude higher than the rates in the Small Wheel. We present the results from performance studies carried out using data collected with these detectors and we also compare the currents drawn by the detector installed in front of the electromagnetic calorimeter with the luminosity measurement in ATLAS.