The L3 forward muon detector

An array of 96 large drift chambers combined with resistive plate chambers for triggering purposes is described. The system extends the acceptance for the muon detection in the L3 experiment at LEP from 62% to 92% of the solid angle. Special features of the system are: economical design, a robust multi-cell structure, short construction time, self-calibrating drift chambers, multiplexed readout and a single wire resolution of about 250 μm. The installation of the full system has been completed during LEP shutdown 1994/1995.