Alignment of the ATLAS Inner Detector Upgraded for the LHC Run II

Abstract

ATLAS is equipped with a tracking system built using different technologies, silicon planar sensors (pixel and micro-strip) and gaseous drift-tubes, all embedded in a 2T axial magnetic field. For the LHC Run II, the tracking system has been upgraded with the installation of a new pixel layer, the Insertable Barrel Layer (IBL). An outline of the track based alignment approach and its implementation within the ATLAS software will be presented. Special attention will be paid to integration in the alignment framework of the IBL, which plays a key role in precise reconstruction of the collider luminous region, interaction vertices and identification of long-lived heavy flavour states. In order to detect as soon as possible deformations and misalignments of the tracking system that may affect the data taking, a fast alignment chain was implemented at the Tier-0 at CERN. Latest upgrades and tests of this fast chain will be discussed, as well as the performance from the Cosmic Ray commissioning run.