OBSERVATION OF HIGH ENERGY COSMIC-RAY WITH SUPERCONDUCTING SPECTROMETER

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Balloon-borne experiment with a superconducting solenoidal magnet spectrometer has been planned to be carried out at Lynn Lake in north Canada in cooperation amongst KEK, University of Tokyo, ISAS, Kobe University and New Mexico State University to investigate cosmic-ray and astro-particle physics. The primary objective is to search for evidence of primordial antimatter in cosmic-rays to study assymmetry of matter/antimatter happened in early history of Universe. The cylindrical spectrometer configuration with a thin superconducting magnet is optimized to provide a large geometrical acceptance of 0.5 - 1.0 m2sr for these scientific objectives.The joint research project has been carried out since JFY 1990. The first preliminary campaign to Canada was carried out in 1990 to survey for optimum ballooning place, and the location of Lynn lake, Manitoba, Canada, was fixed for the ballooning because of the best geological condition very close to magnetic north pole (larger vertical magnetic f … More ield component) and of very empty place. The second campaign was carried out in 1991 and preliminary experiment was carried out to verify a possible large balloon launching. A scientific ballooning was planned in summer of 1992, and the experiment was prepared at Lynn lake for ballooning. Unofortunately, the ballooning was not realized in 1992, because a diplomatic agreement could not in plance within an appropriate time before the scheduled launching. However, the ballooning preparation has been completed and a technical rehearsal for launching was performed and cosmic ray events were observed on ground.As a summary, the following results have been obtained in this joint research project.- Geological survey for ballooning place was made and Lynn Lake was chosen as the best place for ballooning.- Preparation and preliminary experiment for ballooning have been experienced at Lynn Lake, Canada.The experiment has become ready for scientific main flight to be carried out in the next project which has been approved by Ministry of Education, Science and Culture. Less