Calibration of the Tile Hadronic Calorimeter of ATLAS at LHC

The TileCal is the hadronic calorimeter covering the most central region of the ATLAS experiment at LHC. It is a sampling calorimeter with iron plates as absorber and plastic scintillating tiles as the active material. The scintillation light produced by the passage of charged particles is transmitted by wavelength shifting fibers to about 10000 photomultiplier tubes (PMTs). Integrated to the calorimeter, there is a composite device that allows to monitor and/or equalize the signals at various stages of their formation. This device is based on signal generation from different sources: radioactive, Laser, charge injection and minimum bias events produced in proton-proton collisions. Recent performances of these systems as well TileCal calibration stability are presented.