Speaker
Description
We have been working on several projects to develop 32 T to 40 T class all superconducting magnet for end-users. For the first step, four REBCO tapes were estimated: 1) THEVA (TV); 2) Shanghai Superconductor Technology (SST); 3) Faraday Factory Japan (FFJ); and 4) Fujikura (FJK). From this estimation, we found that, except TV’s tape, the coils of all REBCO tapes were suddenly deformed at winding tensions above 50 MPa. In addition, in the case of TV and FFJ tapes, delamination of the tapes easily occurred. In 2024, we received tapes from TV, SST, and FFJ companies that had improved these shortcomings. Therefore, three REBCO mock-up magnets wound with these tapes, each consisting of two metal-as-insulation (MI) double pancake (DP) coils, were constructed. The magnets have the same structure and geometry except for the manufacturer of the REBCO conductors. Their physical properties, the delamination strength and windability of each tape, were estimated during this winding process. Each mock-up magnet was suddenly discharged at 20 A in self-field at 4.2 K to measure its charging time constant. The magnets were charged up to 500 A under various external magnetic fields to investigate its’ real current-carrying performance. In addition, the magnets were repetitively charged and discharged to confirm mechanical stability of the magnets. For estimating critical current, joining strength and our protection scheme, quench tests of the magnets were also conducted under various background magnetic field at 4.2 K.
ACKNOWLEDGMENTS: The authors acknowledge the support of the LNCMI-CNRS, member of the European Magnetic Field Laboratory (EMFL), and of the French National Research Agency (ANR) through the contracts ANR-10-LABX-51-01 (Labex LANEF) and ANR-14-CE05-0005 (NOUGAT project). This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 951714.
