Among key design and operation issues for MgB2 relevant to MRI magnets are: uniformity of current-carrying capacity over long lengths (>;2 km) of wire; and reliability of a splicing technique. This paper presents experimental results of current-carrying capacities of a small test coil and joints, both made from MgB2 round wires, multifilament and monofilament (mono), manufactured by Hyper Tech Research, Inc. The test coils were wound with 95-m long unreacted, C (carbon)-doped MgB2 multifilament wire, sintered at 700°C for 90 min. The critical currents were measured in the 4.2 K-15 K and 0 T-5 T ranges. We have modified our original splicing technique, proven successful with unreacted, un-doped multifilament wire sintered at 570°, and applied it to splice both un-doped and C-doped mono wires sintered at 700°C. Most consistently good results were obtained using the un-doped mono wires. Also presented are results of a small joint-coil-PCS assembly of mono wire, operated in persistent mode at 50 A at >;10 K.

中文翻译：

---

${\rm MgB}_{2}$ 用于 MRI 磁体：测试线圈和超导接头结果

与 MRI 磁体相关的 MgB2 的关键设计和操作问题包括： 长长度（> 2 km）导线的载流能力的均匀性；以及拼接技术的可靠性。本文介绍了 Hyper Tech Research, Inc. 制造的小型测试线圈和接头的载流能力实验结果，这些线圈和接头均由 MgB2 圆线、复丝和单丝（单丝）制成，由 Hyper Tech Research, Inc. 制造。测试线圈缠绕长度为 95 米。未反应的、C（碳）掺杂的 MgB2 复丝线，在 700°C 下烧结 90 分钟。临界电流在 4.2 K-15 K 和 0 T-5 T 范围内测量。我们改进了原来的熔接技术，该技术在 570°C 下烧结的未反应、未掺杂的多丝线中被证明是成功的，并将其应用于熔接在 700°C 下烧结的未掺杂和碳掺杂的单丝线。使用未掺杂的单线获得了最一致的良好结果。还介绍了单线小型联合线圈 PCS 组件的结果，该组件在持续模式下以 50 A、>10 K 运行。