The CMS silicon strip tracker operation and performance

The CMS Silicon Strip Tracker (SST), comprising 9.6 million readout channels from 15148 modules covering an area of 198 m^2, needs to be precisely calibrated in order to correctly interpret and reconstruct the events recorded from the detector, en suring that the SST performance fully meets the physics research program of the CMS experiment. Calibration constants may be derived within several workflows, from promptly reconstructed events with particles as well as from commissioning events gathered just before the acquisition of physics runs. These calibration procedures have been exercised since summer 2009 when the CMS detector has been commissioned using cosmic muons and proton-proton collisions at a center-of-mass energy of 900 GeV, 2.36 and 7 T eV. During these data taking the performance of the SST has been carefully studied: the noise of the detector, the data integrity, the S/N ratio, the hit reconstruction efficiency, the calibration workflows have been all investigated with time and for dif ferent conditions, at the full detector granularity. In this paper we describe the calibration procedures and the detector performance results from the latest CMS operation.