超1 GHz NMR システムの開発

―ビスマス2223 最内層コイルを用いた24 T 超伝導磁石―

抄録

We have successfully upgraded the a 920-MHz (21.6 T) nuclear magnetic resonance (NMR) superconducting magnet to 1020 MHz (24.0 T). The newly developed 3.6-T (Bi,Pb)₂Sr₂Ca₂Cu₃O₁₀ (Bi-2223) innermost coil, which was made of Cu-alloy laminated Bi-2223 tapes, was installed instead of a Nb₃Sn innermost coil. The upgrading project was a technical challenge for a Bi-2223 high-T_c superconductor, not only from a high-field application point of view, but also from the perspective of homogeneous and stable field generation. In this review, the development of the a Bi-2223 innermost coil and the outline for upgrading are introduced. Serious damage caused by the Great East Japan Earthquake is also introduced. Some major accomplishments are shown.