Recently, significant improvement in the strain tolerance of Bi-2223 conductor has been achieved by lamination with high strength nickel alloy. The conductor, supplied by Sumitomo Electric and designated Type HT-NX, is now commercially available in lengths sufficient for manufacture of high-homogeneity solenoids. A program to fully exploit the improved conductor properties is now underway at the National High Magnetic Field Laboratory (NHMFL). Five coils are being made, the last of which is to demonstrate an NMR measurement approaching 1 GHz and 1 ppm over 10-mm volume. In so doing, we expect to demonstrate critical current fraction, and strain similar to that expected in 30-T NMR magnets. The coils will be tested inside an existing 16 Tesla large-bore background magnet at the NHMFL. The design of the NMR demonstration coil is presented first, with expected values for field, homogeneity, and strain given. A technology development program is then outlined, which includes fabrication of four test coils to test various design features, develop fabrication tooling, and train personnel.

中文翻译：

---

用于高分辨率 NMR 磁铁的 Bi-2223 测试线圈

最近，通过与高强度镍合金层压，Bi-2223 导体的应变耐受性得到了显着改善。由住友电工提供并指定为 HT-NX 型的导体现在可在市场上买到，其长度足以制造高均匀性螺线管。国家高磁场实验室 (NHMFL) 目前正在开展一项充分利用改进后的导体特性的计划。正在制作五个线圈，最后一个线圈用于演示在 10 毫米体积内接近 1 GHz 和 1 ppm 的 NMR 测量。在这样做时，我们希望证明临界电流分数和应变与 30-T NMR 磁体中预期的相似。这些线圈将在 NHMFL 现有的 16 特斯拉大口径背景磁铁内进行测试。首先介绍核磁共振演示线圈的设计，给出了场、均匀性和应变的预期值。然后概述了技术开发计划，其中包括制造四个测试线圈以测试各种设计特征、开发制造工具和培训人员。