We report the design, construction, and operation results of an 18 T 70 mm cold-bore high temperature superconductor (HTS) no-insulation (NI) magnet, which is developed for an axion haloscope experiment. The magnet consists of 44 double-pancake coils wound with multi-width and multi-thickness REBa2Cu3O7-x (RE = rare earth) tapes. Owing to the NI feature, the magnet is highly compact; is 162 mm in outer diameter and 476 mm tall; and provides an environment of 0.22 T2 m3 within the cold-bore target space of 66 mm in diameter and 200 mm in length. After an initial performance test at SuNAM Co. Ltd., the magnet was installed at the Center for Axion and Precision Physics Research (CAPP) of the Institute for Basic Science in Daejeon, South Korea, in August 2017. The magnet has been successfully operating at the CAPP since then, except for maintenance in October 2018. The magnet may represent the first high field HTS user magnet that experienced long-term operation of over one year.

中文翻译：

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用于轴子晕镜实验的 18 T 70 mm 无绝缘 (RE)Ba2Cu3O7−x 磁体的设计、构造和操作

我们报告了 18 T 70 毫米冷孔高温超导体 (HTS) 无绝缘 (NI) 磁体的设计、构造和运行结果，该磁体是为轴子晕镜实验开发的。磁铁由 44 个双薄饼线圈组成，缠绕有多种宽度和多种厚度的 REBa2Cu3O7-x（RE = 稀土）带。由于 NI 特性，磁铁非常紧凑；外径 162 毫米，高 476 毫米；并在直径为 66 毫米、长度为 200 毫米的冷钻孔目标空间内提供 0.22 T2 m3 的环境。在 SuNAM Co. Ltd. 进行初始性能测试后，该磁铁于 2017 年 8 月安装在韩国大田基础科学研究所轴子与精密物理研究中心 (CAPP)。该磁铁已成功运行从那时起在 CAPP，