Speaker
Mr
Matthias Schröder
(DESY)
Description
The physics performance of the CMS experiment depends crucially on its tracking detector, which consists of 25000 silicon sensors.
In order to achieve the required tracking precision, it is necessary to align the positions and orientations of the sensors at micrometer level, which involves the adjustment of approximately 200000 parameters.
They are determined simultaneously in a track-based alignment procedure which minimizes the residuals between the measured and expected hit positions of the particle trajectories using the Millepede II program. In this presentation, the alignment procedure at CMS is illustrated and its performance is discussed.
