Commissioning and Early Measurements of the DT Muon Detector of CMS at the LHC

The Drift Tubes (DT) constitute one of the components of the Barrel Muon Detector of the CMS experiment at the CERN's LHC proton-proton collider. In this paper, the final assembly, and the strategy and the results of the commissioning of the DT detector are presented, together with first measurements on cosmic rays, with and without the magnetic field. Although the DT are not best suited for halo muons surrounding the LHC beams, they were nonetheless able to record muons passing through the barrel of CMS during the few days of LHC beam operation in September 2008. The general experience gained by operating the DT's both as a tracking detector and as a trigger for the whole CMS experiment are also reviewed.