Semi conductor tracker Atlas SCT collaboration
We report on the operation and performance of the ATLAS Semi-Conductor Tracker (SCT), which has been functioning for 3 years at the Large Hadron Collider at CERN. The SCT is constructed of 4088 silicon detector modules. We find 99% of the 6.3 million strips are operational, the noise occupancy and hit efficiency exceed the design specifications; the alignment is very close to the ideal to allow on-line track reconstruction and invariant mass determination. We will report on the operation and performance of the detector including an overview of the issues encountered. We observe a significant increase in leakage currents from bulk damage due to non-ionizing radiation which is in agreement with the predictions.We will also cover the time evolution of the key parameters of the strip tracker, including the evolution of noise and gain, the measurement of the Lorentz angle and the tracking efficiency in the harsh LHC environment. Valuable lessons for future silicon strip detector projects will be presented.
We propose a talk that summarizes the data-taking operations of the ATLAS Semi Conductor Tracker at the LHC, including the main difficulties we had to cope to, namely the failure of the optical transmitter on the readout board and the higher current of a subset of sensors.
We have an updated determination of the radiation damage and we can show the performance of the SCT during tha LHC Run-1. The activities during the shutdown consist mostly in increasing the number of readout boards, to cope with a higher trigger rate.