Response of the ATLAS Tile Calorimeter to a radioactive source and muons

The ATLAS hadronic calorimeter calibration is based on a Cs source system and on Test Beam results. They are used not only to do the first inter-calibration of the different components of the calorimeter but also to obtain the initial EM scale for individual cells of TileCal. Since the year 2000, the first production-line modules of TileCal have been constructed and tested by exposing them to muon, pion, and electron beams at CERN SPS. They have also undergone calibration using the radiation from a Cs source. The main goal of the studies of the response of ATLAS Tile Calorimeter to a radioactive source and muons is to qualitativaly compare test beam and source data taken on TileCal production modules in order to understand better the calorimeter calibration procedure.