We present assembly and test results of a 3-nested-coil 800-MHz (18.8 T) REBCO insert (H800) for the MIT 1.3 GHz LTS/HTS NMR magnet currently under completion. Each of the three H800 coils is a stack of no-insulation (NI) REBCO double-pancake coils (DPs). The innermost 8.7-T Coil 1 (26 DPs) was completed by mid-2016; the middle 5.6-T Coil 2 (32 DPs) was completed in mid-2017; while the outermost 4.5-T Coil 3 (38 DPs) was completed in early 2018. Coils 1, 2, and 3 were assembled together in early 2018 as a 3-nested-coil, the H800, and tested, first in liquid nitrogen to a power supply current of 20 A, followed by testing in liquid helium to a power supply current of 251.3 A, the H800's design operating current. After roughly five minutes settling time at 251.3 A, the H800 quenched. In this paper, we examine probable sources of quench initiation and simulate ensuing quench behavior. Remedial efforts to minimize the tendency toward quenching in the H800 are presented and discussed.

中文翻译：

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用于 MIT 1.3 GHz LTS/HTS NMR 磁体的 3 嵌套线圈 800 MHz REBCO 插入件 (H800) 的组装和测试


我们展示了目前正在完成的 MIT 1.3 GHz LTS/HTS NMR 磁体的 3 嵌套线圈 800 MHz (18.8 T) REBCO 插入件 (H800) 的组装和测试结果。三个 H800 线圈中的每一个都是一堆非绝缘 (NI) REBCO 双扁平线圈 (DP)。最里面的 8.7-T 线圈 1（26 个 DP）于 2016 年中期完成；中间5.6-T线圈2（32个DP）于2017年中期完成；最外面的 4.5-T 线圈 3（38 个 DP）于 2018 年初完成。线圈 1、2 和 3 于 2018 年初组装在一起，作为 3 嵌套线圈 H800，并首先在液氮中进行测试电源电流为20A，随后在液氦中进行测试，电源电流为251.3A，即H800的设计工作电流。在大约 5 分钟稳定在 251.3 A 后，H800 淬灭。在本文中，我们研究了淬火引发的可能来源并模拟随后的淬火行为。介绍并讨论了尽量减少 H800 淬火倾向的补救措施。