Calibration of the ATLAS hadronic barrel calorimeter TileCal using 2008, 2009 and 2010 cosmic rays data

Cosmic rays collected in 2008, 2009 and 2010 have been used in the ATLAS experiment to test the calibration of the hadronic barrel calorimeter TileCal. Stable results were obtained for the three periods. The analysis was based on the comparison between experimental and simulated data, and addresses three issues. First, the average non uniformity of the response of the cells within a layer was estimated to be about 2%. Second, the average response of different layers is found to be not intercalibrated, considering the sources of error. The largest difference between the responses of two layers is 4%. Finally, the differences between the energy scales of each layer obtained in this analysis and the value set at test beams using electrons was found to range between -2% and +2%. The sources of uncertainties in the response measurements are strongly correlated and include the uncertainty in the simulation of the muon response. The overall uncertainty in the energy scale is estimated to be 3%.