The barrel muon chamber of the CMS experiment: Recent results

The barrel muon chambers of the CMS-detector are made assembling three superlayers giving φ and θ information. Each superlayer consists of four layers of rectangular drift tubes. Full size prototypes of a CMS barrel muon chamber were recently built to study their performance. Recent results from the test beam with high energy muons, the test beam under an LHC-like irradiation environment and the construction precision will be presented.