Choi Y H, Li Y, Park D, Lee J, Michael P C, Bascuñàn J, Voccio J P, Iwasa Y, Tanaka H
Francis Bitter Magnet Laboratory/Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139 USA.
Department of Mechanical Engineering, Wentworth Institute of Technology, Boston, MA 02115.
IEEE Trans Appl Supercond. 2019 Aug;29(5). doi: 10.1109/TASC.2019.2900057. Epub 2019 Feb 18.
This paper presents results of construction and operation of a persistent-mode, liquid-helium-free, small-scale prototype magnet for the development of a tabletop 1.5-T "finger" MRI system for osteoporosis screening. The prototype magnet, composed of 2 MgB coils, one superconducting joint, and a persistent-current switch (PCS) built from a portion of one coil, was wound with a one continuous ~80-m long unreacted and monofilament MgB wire and then reacted. The test magnet was charged successfully and generated the estimated target field of 1.75 T at 5 K with the proposed PCS operation. During initial persistent-mode, the field was slightly decayed due to the index dissipation of the joint; thereafter it sustained the persistent field of 1.7 T for 35 h. The test results validated the joint resistance of < 1.2 × 10 as well as the proposed approach involving the PCS coil circuit model.
本文介绍了一种用于开发用于骨质疏松症筛查的桌面式1.5-T“手指”MRI系统的持久模式、无液氦小型原型磁体的构建和运行结果。该原型磁体由2个MgB线圈、一个超导接头和一个由其中一个线圈的一部分制成的持续电流开关（PCS）组成，用一根连续的约80米长未反应的单丝MgB线绕制，然后进行反应。测试磁体成功充电，并通过所提出的PCS操作在5 K时产生了估计的1.75 T目标场。在初始持久模式期间，由于接头的指数耗散，磁场略有衰减；此后，它在1.7 T的持久磁场下维持了35小时。测试结果验证了接头电阻<1.2×10以及所提出的涉及PCS线圈电路模型的方法。
