Muon Trigger System in the TOPAZ Detector
                                    ○UJIIE Norihiko, T.Tauchi
      National Laboratory for High Energy Phisics,KEK,1-1 Oho,Tsukuba-shi,Ibarakiken,305 JAPAN
                                      T.Takahashi,Y.Teramoto
Institute for Cosmic Ray Physics,Faculty of Science,Osaka City University,3-3-138 Sugimoto,Simiyoshi,
                                         Osaka 558,JAPAN



 A redundant muon trigger system was
implemented at the TOPAZ detector for the
Phase-II TRISTAN experiment. This system
is mainly based on fast signals from barrel
muon chambers, and is free from the other
tracking detectors. The trigger rates has been
stable at 0.5Hz, which was dominated by
cosmic-ray background.
 The trigger efficiency was obtained to be
92.5+/-0.7% for the process in the polar-
angular region of cosθ(μ)<0.63.
 We will be talk about this trigger system
with TOPAZ detector, developed electronics
module and it function, and results.