The MUON system in the HERA-B experiment

The HERA-B experiment is designed to study CP-violation phenomena in the B-system. B-mesons are produced in interactions of 920 GeV/c beam halo protons with an internal target. The muon system serves to identify muons with momenta greater than 5 GeV/c. Unambiguous muon identification plays a key role for CP violation studies as well as for other important topics of the HERA-B physics program. The overall design of the muon system, the expected and measured performance, and the current status are presented.