Measurement of the front-end dead-time of the LHCb muon detector and evaluation of its contribution to the muon detection inefficiency.

A method is described which allows to deduce the dead-time of the front-end electronics of the LHCb muon detector from a series of measurements performed at different luminosities at a bunch-crossing rate of 20~MHz. The measured values of the dead-time range from $\sim 70$~ns to $\sim 100$~ns. These results allow to estimate the performance of the muon detector at the future bunch-crossing rate of 40~MHz and at higher luminosity.