Study for Muon Identification and Its Trigger in Experiments at Super High Energy Hadron Collider (SSC)

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We have started a muon detector development program of a jet-type drift chamber of its high spatial resolution and two track separation capability. This chamber has two layers of the jet chamber with a half cell staggered. Each jet cell is physically separated from other cells and has only 3 sense wires in it. Therefore even in the case a wire is broken, only the particular single cell will become useless and all other cells can remain healthy. For the purpose of simple trigger, all set of three wires are pointing to the interaction point.With the above basic design of the muon system, we have simulated the performances of the system using the computer codes we developed. The trigger is produced by the mean timer between the staggered pair of top and bottom cells with the additional coincidence with the scintillation counter signal. The trigger rates were carefully studied and it was found that an additional chamber which measures second coordinates needed to reduce the cosmic ray trig … More ger rate. Then that is enough in order to keep the total rate low enough for the data acquisition system for the threshold of 10 to 20 GeV. This trigger logic can not only realize the reasonable rate but also give us position information of the track within the cell with better than 1mm resolution which would be useful for later use in the higher level trigger.Next we have carried a test experiment at the high energy muon beam at Fermilab, Illinois. The test chambers were build by the US collaborators and very similar with our jet chamber. The Japanese group participated the test experiment and analyzed the data. As the result, we found that high energy muons were often accompanied by the EM shower debris, 17% to 30% for the muon energies ranging from 50 GeV to 550 GeV. These data are very precious and were used to tune our simulation program. This enabled us to study the problem under different conditions from those under which we carried in the test experiment.We fabricated a pair of small jet chambers and a large (8m X 3m) chamber to confirm the basic performances and to mainly study mechanical problems for the production of full size chambers, respectively. It was found that the small chambers worked as they were designed, but also found that there are some minor problems in the material and support mechanism of the cathode plates. Right now the large chamber is being modified to solve the problems. key word Detection of Muon Less