ATLAS Tile Calorimeter commissioning and performance

The commissioning of the hadronic Tile Calorimeter (TileCal) of the ATLAS experiment was largely complete and the detector fully operational before the LHC first beam on 10 September 2008. During the installation phase of the experiment, a large number of online tools have been developed in order to test the correct functionality of the hardware. These tools were specifically designed for TileCal from the DVS (Diagnostic and Verification System) of the ATLAS TDAQ software. At the same time, Read-Out software packages were designed and tested to satisfy LHC requirements in particular for high rate data acquisition. In parallel, the commissioning of the slow control system which controls and monitors such things as the low voltage and the high voltage, as well as infrastructure and safety, was ongoing. The large number of channels (almost 10000) and the complexity of the detector require the development of advanced tools for calibrating and validating the online and offline reconstruction. A set of monitoring tools has been also developed in order to certify the various stages of data flow from the detector front-end to the Read-Out Drivers (RODs) and the Read-Out System (ROS) and finally the reconstructed parameters. Additional tools based on the slow read-out system (Integrator read-out) have been developed in order to monitor photo-tube mean currents and provide luminosity and beam condition information. The TileCal detector has been fully integrated with the other subsystems and is intensively involved since the beginning in the commissioning phase with cosmic ray events. Many calibration and performance studies were done using these cosmic data in order to validate the energy reconstruction, the timing, energy loss of muons, etc.