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The OPAL Barrel Time-of-Flight Detector |
The barrel part of the time-of-flight system covers the angular region |cos theta| < 0.82. It generates trigger signals and, by measuring the time of flight from the interaction region, allows charged particle identification in the range 0.6-2.5 GeV. It also aids in the rejection of cosmic rays.
The system consists of 160 scintillation counters forming a barrel of mean radius 2.36 meters which is positioned outside and coaxial with the aluminum coil. Each counter is 6.48 meters long and has a trapezoidal cross section (45 mm thick, 89 to 91 mm wide). The counters are individually wrapped in aluminized mylar and black PVC sheet.
OPAL calorimeters
The endcap time-of-flight detectors