Park Dongkeun, Bascuñán Juan, Michael Philip C, Lee Jiho, Choi Yoon Hyuck, Li Yi, Hahn Seungyong, Iwasa Yukikazu
Francis Bitter Magnet Laboratory / Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Department of Electrical and Computer Engineering, Seoul National University, Seoul, 08826, Korea. (
IEEE Trans Appl Supercond. 2019 Aug;29(5). doi: 10.1109/TASC.2019.2901026. Epub 2019 Feb 22.
We present post-quench analyses of the MIT 800-MHz REBCO insert magnet (H800), unexpectedly quenched during operation in March 2018, and design study of a new 800-MHz HTS insert (H800N). The as-wound H800 was supposed to contribute 18.7 T and, with an LTS background magnet (L500), produce 30.5 T corresponding to a proton resonance frequency of 1.3 GHz. The H800 was operated at 4.2 K in liquid helium and, about 5 minutes after the power supply reached a target operating current of 251.3 A, it experienced a quench. Because the damage in the H800 was more widespread than it first appeared, we decided to design and build a new insert magnet, H800N. In designing H800N, we try to eliminate unanticipated flaws in our H800 design. H800N is to be more stable not to quench and more reliably survive against quench without permanent damage by: 1) adopting a single solenoid structure composed of 40 stacked double pancake coils with improved cross-over sections; 2) enhancing thermal stability; and 3) reducing excessive current margin for quench protection.
我们展示了麻省理工学院800兆赫REBCO插入式磁体（H800）的失超后分析，该磁体在2018年3月运行期间意外失超，还展示了新型800兆赫高温超导插入式磁体（H800N）的设计研究。绕制好的H800本应提供18.7特斯拉的磁场，并与一个低温超导背景磁体（L500）共同产生30.5特斯拉的磁场，对应1.3吉赫的质子共振频率。H800在液氦中4.2K的温度下运行，在电源达到251.3A的目标运行电流约5分钟后，它发生了失超。由于H800中的损坏比最初看起来的更广泛，我们决定设计并制造一个新的插入式磁体H800N。在设计H800N时，我们试图消除H800设计中未预料到的缺陷。H800N将更加稳定，不易失超，并且在失超情况下更可靠地存活而不会造成永久性损坏，方法如下：1）采用由40个堆叠的双饼式线圈组成的单螺线管结构，其交叉截面得到改进；2）提高热稳定性；3）减少用于失超保护的过大电流裕度。
