Design studies of the ATLAS muon Level-1 trigger based on the MDT detector for the LHC upgrade

The present muon Level-1 trigger of the ATLAS detector is given by dedicated detectors; RPC and TGC chambers in barrel and end-cap regions, respectively. The Monitored Drift Tube (MDT) chambers and the Cathode-Strip Chambers (CSC) are used for precision measurements of muon tracks. The performance of the muon Level-1 trigger is limited by the momentum resolution of the trigger chambers. In order to improve the trigger performance, a muon track finding scheme based on MDT signals is envisaged. Studies of the scheme and the algorithm are presented. The trigger latency is estimated to be approximately 3 μs.