Contents I. Introduction
Critical current at high magnetic field is one of the key properties in a practical superconductor. In the past years, the current carrying ability of wire was significantly enhanced via doping and improving the fabrication techniques. Large scale applications, such as MRI systems and high field insert magnets were developed based on the industrialized wire [1]–[8]. For a small magnet, the working current was determined by the critical current at the maximum field point. In a comparatively large magnet system, it was possible to divide the magnet into several sub-assemblies and determine the working current separately according to the superconductor properties and field distributions. In a PC mode operating magnet, the field and temperature effects on the joints and the switches are also important. Encouraged by the successful attempts of jointing wires using a method analogous to the powder in the tube (PIT) approaches in wire fabricating [9], [10], a multi-solenoid magnet with superconducting joints and switches was designed in this study. Here, two types of wires were used for generating the background field in comparatively large bores and for attaining high field at the center. Both liquid Helium and conduction cooling conditions were considered in the design of the magnet. Using a “wind and react” method, pilot coils were prepared and joints were built to form a closed circuit for preliminary tests of PC mode operation.
