The Alignment of the ATLAS Silicon Tracker

Abstract

The alignment of tracking detectors is crucial for the physics programme at the LHC, especially for precision measurements like the W mass. The alignment of the ATLAS silicon tracking detectors with a total of 5832 modules poses an unprecedented challenge. In this poster, two track-based alignment algorithms at ATLAS will be covered: the Global chi^2 Algorithm based on chi^2 minimisation, and the Robust Alignment Algorithm based on centering residual distributions. On a time scale of minutes and hours, the geometry of the silicon tracking detectors can be monitored with the Frequency Scanning Interferometry system. An overview of this system will also be given.