Closed coils fabricated using second generation high temperature superconducting (2G-HTS) coated conductors (CCs) are promising for superconducting magnets, which operating in persistent current mode (PCM) such as magnetic resonance imaging (MRI) and nuclear magnetic resonance (NMR) systems. However, the fabrication and application of superconducting joints for 2G-HTS CCs still pose a significant challenge. This paper reports a PCM joint-less 2G-HTS coil for capturing magnetic fields, which is called ‘Four Pancake Coil (FPC)’. A novel winding method was developed to form four pancake structure and effectively solved the closed-loop problem of 2G-HTS magnets. Meanwhile, the FPCs generated a 70.4 mT central magnetic field at 77 K and lasted for 57 d with a magnetic field drift rate of only 0.065 ppm h⁻¹, which can satisfy the requirements of MRI magnets. In addition to the closed-loop characteristics of the FPC, the stacked magnet also provides expandability and ease of maintenance exchange. These advantages make it highly promising for the development of closed-loop 2G-HTS magnets.

中文翻译：

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新型无接头线圈：有望提供前所未有的磁场稳定性，解决 2G-HTS 磁体应用中的持续电流模式问题


使用第二代高温超导 (2G-HTS) 涂层导体 (CC) 制造的闭合线圈有望用于超导磁体，该磁体以持续电流模式 (PCM) 运行，例如磁共振成像 (MRI) 和核磁共振 (NMR) 系统。然而，2G-HTS CC 超导接头的制造和应用仍然面临着巨大的挑战。本文报道了一种用于捕获磁场的 PCM 无接头 2G-HTS 线圈，称为“四煎饼线圈（FPC）”。开发了一种新型绕线方法形成四薄饼结构，有效解决了2G-HTS磁体的闭环问题。同时，FPC在77 K下产生70.4 mT的中心磁场，持续57 d，磁场漂移率仅为0.065 ppm h ⁻¹ ，可以满足MRI磁体的要求。除了FPC的闭环特性外，堆叠磁体还提供可扩展性和易于维护更换。这些优点使其对于闭环2G-HTS磁体的开发极具前景。