Study of the drift properties of high pressure drift tubes for the ATLAS muon spectrometer

High pressure drift tubes chambers, MDT, are used as precision tracking detectors in the muon spectrometer of the ATLAS experiment at the Large Hadron Collider. MDT chambers, operated at 3 bar absolute pressure with 93% argon 7% carbon dioxide gas mixture, were tested with cosmic rays at the Roma TRE test site and their properties upon variations of the operating conditions are discussed. The possibility to improve the tube spatial resolution measuring a fraction of the collected charge, exploiting the final version of the MDT read-out electronics, is considered.