Persistent-mode, Liquid-helium-free, Robust Bi2212 Magnets for MRI and >1GHz NMR

用于 MRI 和 >1GHz NMR 的持久模式、无液氦、坚固的 Bi2212 磁铁

• 批准号: 9409328
• 负责人: Alexander Otto
• 金额: $ 22.5万
• 依托单位: SOLID MATERIAL SOLUTIONS, LLC
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9409328
• 关键词: Alloys; American; Area; Caliber; Charge; Data; Development; Environmental Wind; Evaluation; Foundations; Goals; Helium; High temperature of physical object; Industry; Joints; Laboratories; Length; Liquid substance; Magic; Magnetic Resonance Imaging; Measures; Mechanics; Methods; Modulus; Performance; Phase; Price; Process; Production; Program Development; Property; Proteins; Psychological reinforcement; Reaction; Refrigeration; Resolution; Sales; Sampling; Small Business Technology Transfer Research; Solid; Stress; System; Techniques; Technology; Temperature; Testing; Texture; Thinness; United States National Institutes of Health; Work; base; cold temperature; cost; density; design; experience; improved; instrument; magnetic field; melting; operation; prevent; programs; prototype; solid state; solid state nuclear magnetic resonance; stress tolerance; wound

Superconducting magnets are required for MRI systems that can operate at elevated temperatures and with higher magnetic field without the expensive and in many places, unavailable liquid helium that is required with Low Temperature Superconductors (LTS), and for enabling NMR instruments to operate above the 23 T LTS field limit. High Temperature Superconductors (HTS) provide the best options for advancing the performance of these instruments at the lower-cost elevated temperatures of mechanical refrigeration provided they can be made with the required form, strength, uniformity and current density into persistent current coils. The Magnet Technology Division (MTD) of the MIT Francis Bitter Magnet Laboratory (FBML), our partner in this Phase I STTR Program, was first to recognize and propose to the NIH in 1999, that HTS-based conductors must be incorporated into MRI and NMR magnets in order to surpass these limits. Among HTS conductors, only 2212 wire can provide superior Je in much higher operating temperatures and magnetic fields while in principle enabling wire forms, for example, round and rectangular, that are proven to work with LTS. However, in order to meet this demand, 2212 coils must be developed with: 1) improved wire stress and bend tolerance in long lengths to allow for simpler coil fabrication and operation with large Lorentz forces, 2) capability for superconducting joints to allow much lower costs and more uniform fields via persistent current operation modes, and 3) high, uniform current densities in layer-wound configurations. Solid Material Solutions (SMS) is now developing coiled forms of strong, rectangular 2212 wire with focus in this program on a first-of-its-kind, persistent mode HTS coil that is made with strong 2212 wire and superconducting joints. Firstly, SMS, with its partner, the MTD at MIT-FBML, will develop a superconducting joint technique for its strong, rectangular, high current density 2212 wire. Joint configuration, melt texture parameters and wire / joint Ic’s will be investigated based on the results of a preliminary study that has already demonstrated that a superconducting joint can be produced between 2212 wire ends. Secondly, the technique will be applied to develop superconducting joints and a prototype persistent current switch. Joints will be prepared between reinforced wire ends and heat treatments completed, followed by Ic tests of joints as well as coiled wire sections. Using the best samples, a method for switching to persistent mode will be established with heaters, and with field-decay rates characterized to demonstrate that persistent current carrying joints can be achieved with coiled strong 2212 wire. Thirdly, a first persistent mode demonstration HTS coil will be designed, produced and tested, based on our strong 2212 wire and coil making know-how. This coil will be designed and built so that it can generate a central field of up to about 5 T at or below Ic, with loop-closing superconducting joints, and heater to allow switching to persistent mode. It will be tested at 4.2 K in driven current mode up to Ic and then with a background field for a total field of > 8 T. It will then be charged to different current levels, followed by switching to persistent mode. Tests will be completed to measure its field decay rates in background fields up to about 4 T, in order to characterize persistent mode properties and demonstrate our capability to produce and operate strong-wire based 2212 coils in persistent mode. When fully developed, this advance will enable the practical production of persistent mode HTS magnets based on our 2212 superconductor, for use in liquid He-free, and higher field MRI as well as >1GHz NMR systems.

核磁共振成像系统需要超导磁体，才能在高温和 更高的磁场，而不是昂贵的，而且在许多地方，低磁场所需的液氦是不可用的 温度超导体(LTS)，以及使核磁共振仪器能够在23T LTS场限以上运行。 高温超导体(HTS)为提高这些材料的性能提供了最佳选择 机械制冷的低成本高温下的仪器，只要它们可以用 将所需的形状、强度、均匀性和电流密度转化为持续电流线圈。磁铁技术部 麻省理工学院弗朗西斯苦磁实验室(FBML)的(MTD)，我们在第一阶段STTR计划中的合作伙伴，是第一个 认识到并在1999年向美国国家卫生研究院建议，基于高温超导的导体必须被纳入核磁共振和核磁共振 磁铁才能超过这些限制。在高温超导导体中，只有2212线能在很大程度上提供优越的JE 更高的工作温度和磁场，同时原则上允许线型，例如圆形和 矩形，已被证明与LTS一起工作。然而，为了满足这一需求，必须开发2212个线圈 具有：1)改进了长长度的导线应力和弯曲公差，从而简化了线圈的制造和操作 具有大的洛伦兹力，2)超导接头的能力，以允许更低的成本和更均匀的场 通过持续电流操作模式，以及3)层缠绕配置中的高、均匀的电流密度。实心 材料解决方案公司(SMS)目前正在开发卷曲形式的坚固、矩形的2212钢丝，该项目的重点是 这是一种首创的持久模式高温超导线圈，由坚固的2212导线和超导接头制成。 首先，SMS将与其合作伙伴MIT-FBML的MTD一起为其开发一种超导连接技术 坚固，矩形，高电流密度2212线。接头配置、熔体纹理参数和线/接头IC 将根据一项初步研究的结果进行调查，这项研究已经证明了超导 接头可在2212根钢丝端部之间生产。 其次，这项技术将被应用于超导接头和持续电流原型的开发 换一下。加固钢丝端部之间的接头将准备好，并完成热处理，然后进行IC试验 接头以及盘绕钢丝部分。使用最佳样本，切换到持久模式的方法将是 用加热器建立的，用场衰减率的特征来证明持续载流接头 可用高强度2212钢丝卷绕而成。 第三，将设计、生产和测试第一个持续模式演示高温超导线圈，基于我们的 强大的2212电线和线圈制造技术诀窍。这个线圈的设计和制造将使其能够产生中心磁场 在IC或更低的温度下，最高可达5T，带有闭合超导接头，加热器允许切换到持久 模式。它将在4.2K的驱动电流模式下进行测试，直到IC，然后使用总场为&gt；8的背景场进行测试 然后，它将被充电到不同的电流水平，然后切换到持久模式。测试将完成 在高达约4T的背景场中测量它的场衰减率，以便表征持久模式 并展示我们在持续模式下生产和运营基于强线的2212线圈的能力。 当完全开发时，这一进步将使基于我们的 2212超导体，用于液体无氦和高场核磁共振以及&gt；1 GHz核磁共振系统。