1. Design and Development of a Compact 1 GHz (23.5 T)-Class NMR Magnet With Bi-2223 Inner Coils
- Author
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Shinji Matsumoto, Hiroto Suematsu, Mamoru Hamada, Masato Takahashi, Yasuyuki Miyoshi, Masatoshi Yoshikawa, R Piao, Hiroki Mochida, Yoshinori Yanagisawa, Tomoaki Takao, Kazuyoshi Saito, Yu Suetomi, and Hideaki Maeda
- Subjects
Materials science ,Bending ,Condensed Matter Physics ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Magnetic field ,Conductor ,Magnet ,0103 physical sciences ,Electrical and Electronic Engineering ,Composite material ,010306 general physics ,Joule heating ,Electrical conductor ,Current density ,Excitation - Abstract
The design and development for a compact 1 GHz (23.5 T)-class NMR magnet are presented. The magnet uses inner coils wound with Ni alloy-reinforced Bi-2223 conductors in combination with LTS outer coils. The series-connected coils are operated in a power supply-driven mode. The total magnet size is very compact, and is comparable to that of a currently commercialized 600-MHz (14.1 T) NMR magnet. This owes to a high current density operation of the Bi-2223 inner coils, which contribute as much as 53% of the total magnetic field. This paper investigated the following properties of the Bi-2223 inner coils: First, joint resistance under external magnetic fields; second, tensile stress tolerances of the Bi-2223 conductor under bending condition; third, high compressive stress on Bi-2223 coils; fourth, the effect of screening current-induced magnetic field on the field homogeneity and stability; and fifth, the maximum permissible Joule heating to avoid a thermal runaway. Two Bi-2223 inner coils for the magnet were built and tested in liquid nitrogen, which provided important knowledge for the magnet excitation.
- Published
- 2019