Speaker
Description
We are developing a helium-free 3T-MRI high-temperature superconducting magnet for whole-body imaging using REBCO wire. The development of a meter-class REBCO magnet has few practical examples, and the problem in the manufacture has not been clarified. Therefore, we grasped the characteristics of REBCO coils by manufacturing meter-class coils and evaluating the current-voltage characteristics of each coil.
The prototype MRI magnet consists of more than 200 single pancake coils. The maximum inner diameter of the coil is φ1.2 m. The REBCO wire is 4 mm wide and insulated with a fluorine-coated polyimide tape. Vacuum impregnation with epoxy was performed to facilitate the handling of the coil. After that, the current-voltage characteristics were acquired for each coil in liquid nitrogen, and it was judged as a good coil or a degraded coil. The yield rate was 82%. To improve the yield rate, we have been investigating the degradation factors of REBCO coils. Based on the insights of the failure mechanisms in the coil winding, possible measures in the coiling has been discussed. Details will be reported in the presentation.
Part of this work was supported by the New Energy and Industrial Technology Development Organization (NEDO).
