Development of demountable superconducting contacts for MRI magnet switches

开发用于 MRI 磁体开关的可拆卸超导触点

• 批准号: 2603036
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2603036
• 关键词: Development; demountable; superconducting; contacts; MRI

The static background field in commercial magnetic resonance imaging (MRI) body scanners is generated by superconducting magnets operating in persistent mode without a power supply. The magnets typically contain more than 10 joints between separate lengths of Nb-Ti multifilamentary superconducting wire, each of which must have a resistance <10-13 omega to enable persistent mode operation. In order to charge the magnet in the first instance, a special joint is needed to form a superconducting switch. On installation of the magnet, the switch is opened to allow current to be driven into the magnet from a power supply and then closed to form a continuous superconducting circuit so the power supply can be removed. Current technology to fabricate a switch exploits the superconducting/normal transition to drive a length of special superconducting switch wire into the normal state during the charging process by heating. Siemens wish to design and test an alternative switch concept which will offer greater flexibility in the design of their commercial magnets. Aims and objectives: This project will develop and test a new switch system capable of controlling a high current superconducting circuit through physically demountable superconducting contacts rather than a separate switching circuit. A successful engineering solution will require a much better understanding of how to control the structure and electrical (superconducting) properties of the contact surfaces that form the switching element. The project is intended to take the concept to Technology Readiness Level 4 - offline concept validation. It will involve investigating and selecting suitable contact materials and explore the processing techniques for creating suitable interfaces or intermediary layers between the main current carrying superconducting materials. Novelty of the research methodology: It is known that superconductor-to-superconductor interfaces rarely allow simple contact joints to operate in the superconducting state because of the short coherence lengths in most available materials and contamination and/or oxidation processes on exposed surfaces. The Superconductivity Group has over the past decade built up a methodology for the design of joints between different classes of superconducting materials, in testing their performance and in correlating this performance with the joint microstructure and nanoscale chemistry analysed using a wide variety of advanced microscopy techniques. The novelty of the project lies in applying these materials selection and analysis techniques to the surfaces and interfaces of a wide range of superconducting materials in order to design and fabricate prototype switches that can be tested using high current facilities in the industrial sponsor, Siemens Healthcare Limited. This project is supported by EPSRC Industrial Collaborative Award in Science and Engineering voucher number 20000165 awarded to Siemens Healthcare Limited, and falls within the EPSRC research themes Engineering, Healthcare Technologies and Manufacturing the Future. Dr Adrian Thomas and M'hamed Lakrimi will be the industrial supervisors of this project.

商用磁共振成像（MRI）人体扫描仪中的静态背景场是由在无电源的情况下以持续模式运行的超导磁体产生的。磁体通常在Nb-Ti多芯超导导线的单独长度之间包含多于10个接头，每个接头必须具有<10-13 Ω的电阻以实现持续模式操作。为了在第一种情况下对磁体充电，需要一个特殊的接头来形成超导开关。在安装磁体时，开关打开以允许电流从电源驱动到磁体中，然后闭合以形成连续的超导电路，因此可以移除电源。制造开关的当前技术利用超导/正常转变来在充电过程期间通过加热将一段特殊的超导开关线驱动到正常状态。西门子希望设计和测试一种替代开关概念，这将在其商业磁体的设计中提供更大的灵活性。宗旨和目标：该项目将开发和测试一种新的开关系统，该系统能够通过物理上可拆卸的超导触点而不是单独的开关电路来控制高电流超导电路。一个成功的工程解决方案将需要更好地理解如何控制形成开关元件的接触表面的结构和电（超导）特性。该项目的目的是采取的概念，技术准备水平4 -离线概念验证。它将涉及调查和选择合适的接触材料，并探索在主要载流超导材料之间创建合适界面或中间层的处理技术。研究方法的新奇：众所周知，超导体-超导体界面很少允许简单的接触接头在超导状态下工作，因为大多数可用材料的相干长度很短，暴露表面上有污染和/或氧化过程。超导小组在过去十年中建立了一种方法，用于设计不同类别超导材料之间的接头，测试其性能，并将此性能与使用各种先进的显微镜技术分析的接头微观结构和纳米级化学相关联。该项目的新奇在于将这些材料选择和分析技术应用于各种超导材料的表面和界面，以设计和制造原型开关，这些开关可以使用工业赞助商西门子医疗保健有限公司的高电流设施进行测试。该项目得到了EPSRC工业科学与工程合作奖的支持，该奖项授予西门子医疗保健有限公司，编号为20000165，福尔斯EPSRC研究主题工程，医疗保健技术和制造未来。阿德里安托马斯博士和穆罕默德Lakrimi将是这个项目的工业主管。