Alignment of the ATLAS Inner Detector

ATLAS is one of the two general purpose detectors at the world’s largest particle accelerator, the Large Hadron Collider (LHC). The LHC will be colliding proton beams at a center of mass energy √s= 14 TeV, it is currently operating at √s = 7 TeV. During the commissioning phase since September 2008, the ATLAS recorded cosmic-rays data and proton-proton collisions at √s = 0.9 TeV. This data has extensively been used for the alignment and calibration of various sub-detectors. The ATLAS has a precision tracking system installed closer to the beam pipe for the measurements of the position and momentum of particle trajectories emerging out of collisions. The precise knowledge of misalignment of the tracking devices is crucial for the important physics measurements. This article gives an overview of the alignment strategy and the alignment performance using the data collected from proton-proton collisions at 7 TeV.