Large - scale performance studies of the Resistive Plate Chamber fast tracker for the ATLAS 1st - level muon trigger

The Resistive Plate Chambers provide the 1st - level muon trigger and the measurement of the non bending coordinate in the barrel region of the muon spectrometer of the ATLAS experiment. Calibrating such a system means fine tuning thousands of parameters (involving both front - end electronics and gap voltages), as well as constantly monitoring performance and environmental quantities such as gap efficiency, average cluster size, temperature, gas flow, gap currents, counting rates. In this paper the RPC calibration effort will be presented. An overview of the performance measurements done using cosmic rays will be also given.