Performance of the Resistive Plate Chambers as LVL1 ATLAS muon trigger detectors

Resistive Plate Chambers (RPC) are used for the fast tracking trigger in the barrel region of the muon system which forms the outer shell of the ATLAS experiment at the Large Hadron Collider (LHC). This work reports on the results obtained with data taken during a combined run of Inner detector, Calorimeter and Muon system in 2009, where the trigger was provided by the RPC. Results on RPC performance with respect to trigger alignment, coverage and efficiency using the entire ATLAS barrel trigger system will be presented. Finally, we review offline monitoring tools developed in the ATLAS software framework to provide fast feedback on RPC data quality.