The design approach and innovations for the largest, uniform field, superconducting solenoid magnet

Design, development, manufacture, and acceptance testing of the Preprototype Magnet System (PMS) was undertaken in April 1978 under contract with the TRW Energy Systems Group as sponsored by DOE for Advanced Isotope Separation System Development. The PMS began operation in September 1981. The principal design requirement was to provide a uniform magnetic field of 20,000 gauss ±0.1% for a 5-meter-long by 0.75-meter-diameter test region. The paper presents the magnet design, manufacturing and in-process test approach taken to meet this requirement. This includes the development of equipment and techniques for ensuring winding integrity and the method of achieving field uniformity during manufacture. Design innovations for coil cryostat components are also presented. These include 1) the cold mass support strut, which was redesigned from a previously proven configuration due to manufacturing scaling problems, 2) the thermal shield, which was simplified from the previous full-flow configuration, 3) the layer-to-layer insulation configuration, which must provide for sufficient LHe circulation, and 4) the coil overbanding configuration, which prevents conductor movement when the coil is energized.