The OPAL Muon Endcap Detectors
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The OPAL Muon Endcap Detectors


Cut-away view of OPAL with muon endcaps highlighted

The OPAL muon endcap ("ME") detectors were built by physicists from Birmingham, with support from the Rutherford Appleton Laboratory. They have been operated and maintained since OPAL data-taking began in 1989 by the Birmingham group, and will continue operating until the end of the year 2000.

The endcap muon detectors cover the angular range 0.67 < |cos(theta)| < 0.985. At each end of OPAL an area of about 150 square meters is covered with four layers of limited streamer tubes which are perpendicular to the beam axis. Each endcap consists of 8 quadrant chambers (6 meters x 6 meters) and 4 patch chambers (3 meters x 2.5 meters). Each chamber consists of two layers of streamer tubes, spaced by 19 mm, one layer having vertical wires and the other horizontal wires.