Construction and Test of New Precision Drift-Tube Chambers for the ATLAS Muon Spectrometer

摘要

ATLAS muon detector upgrades aim for increased acceptance for muon triggeringand precision tracking and for improved rate capability of the muon chambers inthe high-background regions of the detector with increasing LHC luminosity. Thesmall-diameter Muon Drift Tube (sMDT) chambers have been developed for thesepurposes. With half of the drift-tube diameter of the MDT chambers andotherwise unchanged operating parameters, sMDT chambers share the advantages ofthe MDTs, but have an order of magnitude higher rate capability and can beinstalled in detector regions where MDT chambers do not fit in. The chamberassembly methods have been optimized for mass production, minimizingconstruction time and personnel. Sense wire positioning accuracies of 5 ?miconshave been achieved in serial production for large-size chambers comprisingseveral hundred drift tubes. The construction of new sMDT chambers forinstallation in the 2016/17 winter shutdown of the LHC and the design of sMDTchambers in combination with new RPC trigger chambers for replacement of theinner layer of the barrel muon spectrometer are in progress.