[AP3] Magnets (for accelerator, fusion)

4:45 PM - 5:15 PM JST(7:45 AM - 8:15 AM UTC)

[AP3-01-INV] Nb₃Sn Conductor Development in Japan for Future High Field Accelerator Magnets

*Michinaka Sugano¹ (1. High Energy Accelerator Reserach Organization (KEK) (Japan))

Keywords:

Nb3Sn wires,non-Cu Jc,Accelerator magnets

For future energy frontier hadron colliders, superconducting dipole and quadrupole magnets with a higher magnetic field must be developed. For instance, in the latest design of FCC-hh, main dipole magnets with a nominal field of 14 T will be installed in the main ring, which has a circumference of 91 km, to achieve a center-of-mass energy of 85 TeV. Nb₃Sn wires are currently considered to be the baseline conductors for these magnets. The requirement of non-Cu J_c of the Nb₃Sn wires for the 14 T dipole magnets is 1200 A/mm² at 4.2 K and 16 T, which is achievable only in the state-of-the-art commercially available Nb₃Sn wires. To construct more than 4000 main dipole magnets, such high-performance Nb₃Sn wires need to be produced with ten times larger total amount than those procured for ITER. However, at present, only one manufacturer in the world is capable of mass-producing the Nb₃Sn wires with the target performance. Based on this background, CERN and KEK launched collaborative research in 2016, aiming for improvement in non-Cu J_c of Nb₃Sn wires. During this 1st phase R&D over 6 years, non-Cu J_c of 1100 A/mm²at 4.2 K and 16 T was achieved in distributed-tin (DT) wires produced by Japan Superconductor Technology (JASTEC). Then, CERN and KEK have been conducting new collaborative research since 2024 within the framework of High Field Magnet programme (HFM). Two Japanese wire manufacturers, JASTEC and Furukawa Electric, and the academic partners, National Institute for Materials Science (NIMS) and Tohoku University, are involved in this R&D program. Among the three major tasks for this collaborative research, the most prioritized one is the industrialization of DT wires. The other two tasks are mechanical reinforcement against a transverse compressive stress and further improvement in non-Cu J_c. In this presentation, we will report the current status of the fabrication and characterization of Nb₃Sn trial wires.