Time Calibration of TileCal Modules with Cosmic Muons

A method to synchronize TileCal readout in time using cosmic muons has been developed. It is based on the comparison between the expected time of flight of muons crossing TileCal cells and the measured time. The method has been applied to cosmic data from September and October of 2007, when different sub-detectors of ATLAS were integrated during the Milestone Weeks. The resolution reached with this method is better than 0.7 ns when the statistical error is not the main contribution to the uncertainty.