Advanced alignment of the ATLAS tracking system

AbstractIn order to reconstruct the trajectories of charged particles, the ATLAS experiment exploits a tracking system built using different technologies, silicon pixel modules or microstrips and gaseous drift tubes, all embedded in a 2T axial magnetic field. Misalignments of the active detector elements and deformations of the structures (which can lead to Weak Modes) deteriorate resolution of the track reconstruction and lead to systematic biases on the measured track parameters. The applied alignment procedures exploit various advanced techniques in order to minimise trackhit residuals and remove detector deformations. For the LHC Run II, the Pixel detector has been refurbished and upgraded with the installation of a new pixel layer, the Insertable B-layer