The ATLAS Level-1 Muon Barrel Trigger timing studies using combined trigger and offline tracking

We present here the strategy and tools developed to time in all the elements of the Level-1 Muon Barrel Trigger of the ATLAS experiment at the CERN Large Hadron Collider. A perfect synchronicity among the various trigger elements and with the LHC Bunch Crossing time is vital for the correctness of the ATLAS physics results. We review the possible sources of delays and how they are accounted and corrected for, using a large sample of cosmic ray data collected by ATLAS; and present initial results, that will be refined with early LHC collision data.