Performance and operation experience of the Atlas Semiconductor Tracker

After more than 3 years of successful operation at the LHC, we report on the \noperation and performance of the ATLAS Semi-Conductor Tracker (SCT) functioning in a \nhigh luminosity, high radiation environment. The SCT is constructed of 4088 silicon detector \nmodules, for a total of 6.3 million strips. Each module is designed, constructed and tested \nto operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules \nare mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 \ndisks on each end of the barrel). The SCT silicon micro-strip sensors are processed in the planar \np-in-n technology. The signals are processed in the front-end ABCD3TA ASICs, which use a binary \nreadout architecture. Data is transferred to the off-detector readout electronics via optical fibres. We \nfind 99.3% of the SCT modules are operational and the hit efficiency exceed the design \nspecifications. We will report on the operation and performance of the detector, including an \noverview of the issues encountered. We will report the expected observation of significant increases \nin leakage currents from bulk damage due to non-ionizing radiation and make comparisons with the predictions. \nWe will also cover the time evolution of the key parameters of the strip tracker, including the evolution of noise \nand gain and the tracking efficiency in the harsh LHC environment. Valuable lessons for future silicon \nstrip detector projects will be presented.