The Monitored Drift Tube (MDT) chambers for the muon precision tracking inthe ATLAS spectrometer

The ATLAS muon spectrometer has been designed to exploit the very wide rang e of the physics potentialities at LHC. One of the very ambitious goal to b e achieved is the precise measurement of the muon tracks, up to very high m omenta, at luminosity L greater than or equal to 10(34)cm(-2)s(-1). To attain the goal, a system of three large superconducting air core toroid magnets, instrumented with very high precision tracking chambers, has been adopted. The high precision of the MDT tracking chambers is achieved throu gh a rigorous assembly procedure in which a very precise jig is used. The various aspects of the system and the MDT chamber assembly procedure ar e described in the following.