DEVELOPMENT OF 750MHZ SUPERCONDUCTING PROBE

750MHZ超导探头的研制

• 批准号: 7369574
• 负责人: William W Brey
• 金额: $ 4.63万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7369574
• 关键词: DEVELOPMENT; 750MHZ; SUPERCONDUCTING; PROBE

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Superconducting NMR probes contain cooled rf coils made of superconducting material that result in improved signal to noise for the experiment. These are commercially available at 500 and 600 MHZ and the goal in Core 3 is to construct improved probes at 750MHz in collaboration with colleagues at the NHMFL and Bruker Instruments. In the spring of 2003, we changed our goal to a 600 MHz 1 mm HCN probe with a single-axis pulsed field gradient. Withers has already built the mounting hardware and 13C and 2H coils. They are now building the 1H and 15N coils, and their initial attempt lead to a 1H coil which resonated ~5% in frequency than expected. The batch of coils they tested all had unusually low Q values, and they now are convinced that coils were made from a bad batch of YBCO superconducting film. More superconducting wafers will be coming soon, and with the help of Saikat Saha, a postdoctoral associate at the NHMFL, we are also making real progress in modeling and better understanding the behavior of the HTS resonators. It appears that with this improved understanding we can improve our ability to design for new frequency and size requirements, but we may also be able to improve the current handling and RF homogeneity of the resonators. Dr. Saha has been using a method of moments (MoM) simulation package (IE3D from Zeland Software) to model resonance frequency and current distribution in HTS coil designs. The MoM approach is faster and more practical for planar coils, which must be subdivided into hundreds of quasi-2D cells. It handles only planar dielectrics, but it is possible to include the cylindrical shield used in the cryoprobe. We anticipate testing a working probe during this next year. If this works, this 1 mm HTS probe will have the highest per volume S/N in any probe built to date.

这个子项目是利用由NIH/NCRR资助的中心拨款提供的资源的许多研究子项目之一。子项目和调查员(PI)可能从另一个NIH来源获得了主要资金，因此可能会出现在其他CRISE条目中。列出的机构是针对中心的，而不一定是针对调查员的机构。超导核磁共振探头包含由超导材料制成的冷却射频线圈，从而改善了实验的信噪比。这些探测器可以在500 MHz和600 MHz的频率下商用，而Core 3的目标是与NHMFL和Bruker Instruments的同事合作，在750 MHz的频率上构建改进的探测器。在2003年春天，我们将目标改为600 MHz 1 mm HCN探测器，具有单轴脉冲场梯度。威瑟斯已经建造了安装硬件和13C和2H线圈。他们现在正在建造1H和15N线圈，他们最初的尝试导致了1H线圈的共振频率比预期的高出5%。他们测试的线圈都有异常低的Q值，现在他们相信线圈是由一批劣质的YBCO超导薄膜制成的。更多的超导晶片将很快问世，在NHMFL博士后Saikat Saha的帮助下，我们在建模和更好地了解HTS谐振器的行为方面也取得了真正的进展。有了这一改进的理解，我们似乎可以提高我们针对新的频率和尺寸要求进行设计的能力，但我们也可能能够改进谐振器的电流处理和射频均匀性。Saha博士一直在使用矩量法(MOM)仿真包(Zeland Software的IE3D)对高温超导线圈设计中的谐振频率和电流分布进行建模。对于必须细分为数百个准2D单元的平面线圈，MOM方法更快速、更实用。它只处理平面电介质，但也可以包括用于低温探测器的圆柱形屏蔽体。我们预计将在明年测试一个工作探测器。如果成功，这个1毫米高温超导探头的单位体积S/N将是迄今为止建造的所有探头中最高的。