Operation of the CMS Silicon Tracker

The CMS tracker is the largest silicon detector ever built, covering 200 square meters and providing an average of 14 high-precision measurements per track. The use of tracker data for reconstruction of charged particles and primary and secondary vertices requires fine-grained monitoring and calibration procedures as well as accurate alignment. Results from timing and threshold optimization, gain calibration, and Lorentz angle determination are shown and the impact on resolution and dE/dx measurements is discussed.