Pulsed superconducting magnet is becoming more attractive for future accelerators and for improving existing ones to realize higher accelerating energy. The technique being now developed in the high energy physics laboratories is also generally very important from the standpoint of A. C. electrotechnical application of superconductors, i.e., practical problems of A. C. loss, wire technique, winding technique, cooling and cryogenic problems, radiation problem, etc. The requirements and engineering problems for development of a superconducting synchrotron magnet are discussed. The project at CERN is presented. The state of the art and experience with various conductors and winding method in several laboratories are briefly reviewed.
We have researched mechanical properties of plastic films and synthetic papers for the cryogenic applications. These tensile properties were measured at the liquid nitrogen temperature 77k, the room temperature 300k and the medium temperature 173k. Specimens were selected out of electrical insulating materials; 8 kinds of plastic films and 5 kinds of synthetic papers. Consequently in plastic films polyethylene telephthalate, polypropylene and polyimide had good mechanical properties from the room temperature to the liquid nitrogen temperature. Especially polyethylene telephthalate and polypropylene showed the marvellous elongation over 40% at the liquid nitrogen temperature. In synthetic papers polyethylene paper (Tyvek) had the better mechanical property in comparison with the other papers. It showed the elongation of 12% at 77k, although polyethylene film showed the poor elongation of 2.4% at 77k.
The pressure drop of single phase liquid nitrogen flow in horizontal tube was measured. The tubes investigated were 0.305, 0.204 and 0.0723cm inner diameter and 200cm long and were immersed into the liquid nitrogen contained in a vacuum insulated vessel. Experiments were made with a Reynolds number range of 500-20, 000. The experimental data were presented in terms of the Fannings friction factor. The results were in good agreement with theoretical line of newtonian liquid in the range of laminar flow and were approximately fit for the data obtained by newtonian liquid such as water in turbulent flow.