Calibration of the Barrel Muon Drift Tubes of CMS

In this report, the description of the CMS Drift Tube (DT) chambers and their calibration procedure is presented and the main results obtained with data collected during the high statistics cosmic ray runs, taken by the experiment at the end of 2008, are reported. The accurate measurement of the main calibration conditions provide the necessary space-time relationship and leads to the expected nominal DT local reconstruction resolution