Optimization Design of a 6 T Fast Cycling Dipole Prototype With Round Cable

A superconducting fast cycling dipole prototype with a central field of 6 T and ramp rate of 1 T/s for ion synchrotron is currently under development at Institute of Modern Physics (IMP). The magnet utilizes a modified cos θ coil design, employing multi-strand round cable in formed grooves. The ribs of straight section of the coil formers have been removed to improve the excitation efficiency. Low loss round cables, made from NbTi/CuMn superconducting wires with a filament of 4.1 um, and the G10 formers are used to reduce AC losses during the ramping operation. The copper cold conduction strips are arranged between layers to improve the cooling efficiency. Bladder and key technology is adopted to prestress the coils. 2D layout of the coil is obtained through a linear programming code. This paper presents the round cable design, 2D cross section optimization, coil end and mechanical design, thermal analysis of the magnet, as well as the development of a technical prototype.