The MIRAI Program and the New Super-High Field NMR Initiative and Its Relevance to the Development of Superconducting Joints in Japan
The MIRAI Program and the New Super-High Field NMR Initiative and Its Relevance to the Development of Superconducting Joints in Japan
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DOI：
10.1109/tasc.2019.2905360
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发表时间：
2019-03
影响因子：
1.8
通讯作者：
H. Maeda;J. Shimoyama;Y. Yanagisawa;Y. Ishii;M. Tomita
中科院分区：
文献类型：
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作者：
H. Maeda;J. Shimoyama;Y. Yanagisawa;Y. Ishii;M. Tomita
使用低温超导导体的磁体需要液氦冷却，但只能产生<24 T的磁场。为了实现全面商业化，高温超导（HTS）导体是首选，因为它们可以通过液氮冷却，从而实现电力传输线。此外，它们可以在液氦中产生超过30 T的更高磁场，这使得它们适用于超高场核磁共振（NMR）。不幸的是，单个高温超导导体的最大长度较短，需要许多接头，导致制造过程困难且操作程序复杂。因此，我们于 2017 年启动了 MIRAI 项目，重点开发连接 HTS 的连接技术。该项目有两个重要的研发方向：1）开发用于持续模式1.3 GHz（30.5 T）核磁共振磁体的超导接头，即日本的超高场核磁共振计划。 2）开发超导直流馈电电缆之间的超低电阻接头，能够连接相距2-5公里的相邻铁路变电站。本文首先概述了 MIRAI 项目。其次，它将描述持久模式核磁共振磁体超导接头研究的初步结果。还将讨论 1.3 GHz NMR 磁体的初步设计。
Magnets using low temperature superconducting conductors require liquid helium cooling, yet can only generate a magnetic field <24 T. For full-fledged commercialization, high temperature superconducting (HTS) conductors are preferred as they can be cooled by liquid nitrogen, enabling electric power transmission lines. Furthermore, they can generate a much higher magnetic field, in excess of 30 T, in liquid helium, which makes them applicable to super-high field nuclear magnetic resonance (NMR). Unfortunately, the short maximum length of a single HTS conductor requires many joints, resulting in a difficult manufacturing process and a complicated operating procedure. Thus, we have commenced the MIRAI Project in 2017, focusing on developing joining technologies for linking HTS. The program has two important research and development directions: 1) Development of superconducting joints for a persistent mode 1.3 GHz (30.5 T) NMR magnet, i.e., The Super-High Field NMR Initiative in Japan. 2) Development of ultra-low resistance joints between superconducting dc feeder cables, enabling to connect adjacent railway substations that are 2–5 km apart. This paper first overviews the MIRAI Project. Second, it will describe initial results from investigations on superconducting joints for a persistent mode NMR magnet. Preliminary designs of the 1.3 GHz NMR magnet will also be discussed.