Cosmic tests of the ATLAS Semi-Conductor Tracker Barrels

The central inner detector of ATLAS consists of the Pixel tracker, the SemiConductor Tracker (SCT) and the Transition Radiation Tracker(TRT). The SCT modules have been tested at several stages from module production to integration with the TRT. The module noise average per channel has been stable and is well below the design specification of 5x10-4 and 99.8% of the 3.2 million channels of the SCT barrels are functional. The SCT barrel is now fully integrated with the TRT barrel and a segment of these two detectors have undergone a cosmics test. A large sector (468 SCT modules) has been timed in and read out during the cosmic tests. Tracks have been reconstructed through the SCT and the TRT sectors