Design and construction of an eight Tesla insert coil

The background field for the first phase of the test facility SULTAN Will be generated by two concentric solenoids: a 6 Tesla outer coil with a free bore of 1.3 m and an inner coil for increasing the field to 8 Tesla. The free bore (cold) will be 1.055 m. In this paper the design of the 8 Tesla inner coil is described. This coil will operate at an overall current density of 23 × 10⁶A/m². The coil will be cooled directly by forced flow supercritical helium. A hollow conductor is applied, composed of a rectangular copper tube and a 26 strands Rutherford cable, soldered on one side of the tube. The copper tube will be cold worked to cope with the high stress level (165 MPa). The design base (field and stress analysis, cooling, stability) and the mechanical design will be outlined. The progress of the coil construction will be indicated.