Time Calibration of the LHCb muon System

The LHCb muon System consists of about 122,000 frontend channels. It plays a basic role in the first trigger level. The trigger requires 95% efficiency in muon tracks detection. It is then necessary to reach a system time alignment at the level of about 2 ns. This alignment must be monitored against possible fluctuations due to changes in the detector operating conditions. We describe the custom instrumentation implemented at system level for time calibration, the strategy adopted, the procedure to be followed both for system alignment and monitoring, the control program realized for this purpose. We also illustrate first results obtained during the detector commissioning in the LHCb pit.