TRIUMF brown reports TRI-68-3

A study has been conducted for the purpose of developing a design for the TRIUMF main magnet coils which was to result in a minimum capital investment when the costs of the coils and the power supply were added together. Two basic designs were considered, one being the more conventional design employing extruded square hollow conductor, the other making use of rectangular conductor bars. The conventional design was found to be unsuitable for the TRIUMF coils due to lack of space for the large number of water circuits that would be needed in order to prevent excessive temperature rise and destructive shear forces to develop within the coil. In addition, the coils would have to be wound at the site due to their large size, making the fabrication work unduly expensive. The rectangular bar design permits the coils to be divided into segments, thus making it feasible to do the manufacturing work in a coil manufacturer’s plant. Minimum capital investment is achieved if the coils are made in 120-degree segments using extruded aluminum as conductor material. Sixty-degree segments are more expensive than 120-degree segments but offer certain advantages which are not found in the 60-degree segment version. Thus, the magnetic field irregularities produced in the segment junction areas occur in six places, which is preferable to having the field distortion in only three places. The 60-degree segments also provide a desirable flexibility between all magnet sectors permitting individual height adjustment of the magnets. The cost of power supplies with various output characteristics has been estimated. Two preliminary cost estimates were received from two power supply manufacturers. These estimates were based on a power supply with an output current of 16,000 amperes and an output power of 2 megawatts. As a result of the findings, it has been recommended that extruded bar aluminum conductor be employed in the fabrication of the coils and that 60-degree segments be used. The conductors should be insulated from each other and from ground by means of glass-epoxy laminates. It is also proposed that the insulation be reinforced by expoxy potting of the coil segments. The epoxy should be formulated to give maximum radiation resistance, and alumina grains should be used to further enhance this property. Bolted flexible copper connectors have been recommended for use between coil segments. The recommended coil design is shown on various figures and drawings included in the report along with graphs demonstrating power demands, capital investment costs and operating costs for different conductor materials and different number of coil turns. On title page: WMB&A-179-1R1TRIUMFUnreviewedResearche