In situ performance of the Transition Radiation Tracker of the ATLAS detector

The Transition Radiation Tracker (TRT) is the outermost of the three tracking subsystems of the ATLAS Inner Detector at the Large Hadron Collider. It is a straw-tube based gas detector providing continuous tracking as well as particle identification capability. The TRT has been successfully commissioned with data collected from millions of cosmic ray muons. In this talk, we present a study of the in situ performance of the detector, with particular emphasis on the measurement of the robustness of track reconstruction.