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

The ATLAS iron-scintillator hadronic calorimeter (TileCal) provides precision measurements of jets and missing transverse energy produced in the LHC proton-proton collisions. Results assessing the calorimeter calibration obtained using cosmic ray muons collected in 2008, 2009 and 2010 are presented. 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 inter-calibrated, 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 -3% and +1%. The sources of uncertainties in the response measurements are strongly correlated, including the uncertainty in the simulation. The total error of each layer determinations is 2%. Stable response values were obtained for the three data-taking periods. The uncertainties on the comparisons are less than ±1% for the Barrel layers and less than ±3% for the Extended Barrel ones.