Message-Id: <199905270203.LAA01228@neutrino.kek.jp> Subject: Horn status Date: Thu, 27 May 1999 11:03:44 +0900 From: Koichiro Nishikawa <nishikaw@neutrino.kek.jp> Dear Collaborators, We have talked with beam channel group about horn repairing yesterday (5/26). The report of the problem of current feeder line has been shown. The inspection shows that the most of the break ocuurs at the boundary of soldering at the end of wire. As you know already, the problem has been the Lorentz force on the stranded wires which were installed in order to accommodate positional adjustment of the horn and the bus-bar. Each stranded wire carries about 4000A and it consists of seven 2.6mm diameter wires. When the current run through the wire, it not only pull the near-by wire but also try to un-strand the wire, resulting twisting force. To remedy this problem, the stranded wires will be replaced by sets of 6mm thick 60mm wide cupper plates. As the result, the horn system will be rigidly fixed and will allow no movement and no adjustment in direction. I believe this pose no problem since we have done the studies on the relation of neutrino beam and direction of horn. The schedule will be as follow. The replacement work will start on May 28(Fri.) and hopefully finished by June 1. We want to have 24-hours test without beam. If the work goes smoothly, the experiment will start at mid-night on June 3 after the tunning by beam channel group. Also we are planning to operate horn with 200kA to make the risk minimum. Sincerely, K.Nishikawa
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