The precision drift chambers for the ATLAS muon spectrometer

The parameters of the stand-alone muon system have been optimised to detect, also as a stand-alone system, the Standard Model Higgs boson as well as supersymmetric particles. The momentum resolution is typically 2–3% over most of the |η| range up to η=2.7. Above 200 GeV of transverse momentum (pT) position measurement and alignment errors begin to dominate and the resolution decreases to 10% at pT=1 TeV. The bulk of the magnet volume is instrumented with Monitored Drift Tubes 3 cm in diameter, each having a spatial resolution of typically 80 μm using an Ar–CO2 mixture at 3 bar.