Hybrid accelerator magnets based on dog bone shaped CORC® wire inserts for operation beyond 20 T (Topic 35b)

The next-generation low-inductance accelerator magnets generating magnetic fields exceeding 20 T require the use of high-temperature superconductor (HTS) insert magnets that operate within a low-temperature superconducting outsert. No insert magnet technology based on HTS cables exists that could deliver a dipole field of 20 T in combination with existing LTS outserts. The proposed program aims to develop a novel HTS insert, compatible with current state-of- the-art HTS Conductor on Round Core (CORC®) wires, that would generate a dipole field of 20 T within LTS outserts currently under development. During Phase I of the program, a novel insert dipole with 40 – 50 mm diameter aperture in which the inner windings contain a dog bone shape will be designed. The dog bone shape prevents the CORC® wire from being bent below its safe limit of 60 – 70 mm diameter. The insert magnet would be sufficiently compact to allow operation within the 130 mm diameter bore of an LTS outsert. Methods to wind CORC® wires into the complex dog bone shape will be developed. The feasibility of the approach will determined by winding small prototype coils and to determine whether the CORC® wire performance retention is at least 90 – 95 % and that the CORC® wire carries sufficient current needed to reach a combined field of 20 T. During Phase II, larger prototype coils will be manufactured and tested within the 90 mm diameter bore of an 8 T outsert dipole magnet to ensure the CORC® wire is supported sufficiently to withstand the high operating stresses. The proposed technology would provide the high-energy physics community with a straightforward path towards the development of reliable 20 T LTS/HTS hybrid accelerator magnets. Novel dog bone shaped insert dipoles based on HTS CORC® wires will enable next generation of high-energy physics magnets, light-weight turn-key gantry systems for proton cancer treatment facilities, compact fusion magnets for energy generation, and numerous other scientific magnets. These magnets will also benefit superconducting magnetic energy storage systems for use in the power grid and within the Department of Defense.