A 1.5-T superconducting solenoid-dipole magnet for a magic-angle spinning field

描述(由申请人提供)：此两阶段计划的第一阶段有两个具体目标：1)成功完成具有显著磁场强度的魔角场(MAF)磁体，其具有核磁共振质量的场均匀度，用于慢速MAS(魔角旋转)磁共振/核磁共振；以及2)应用和演示拟议的系统，该系统适用于超导磁体在第一阶段(~0.1赫兹)和第二阶段(6赫兹)缓慢旋转。不同于传统的具有仅指向一个轴的核磁共振质量的场矢量的核磁共振或核磁共振磁体，MAF矢量可被分解成两个场矢量，一个指向一个轴，另一个指向与第一轴垂直的方向。确保与磁体轴(也是旋转轴)成54.74度角的核磁共振质量场的最好方法，也可能是最简单的方法，就是独立地确保由组成MAF磁体的每个线圈产生的核磁共振质场。这就是我们成功制造超导MAF磁体的创新设计理念的关键：一个轴向z场螺线管线圈和一个x轴场偶极线圈的组合，每个线圈产生特定强度的核磁共振质量场。通过调整每个线圈的磁场强度，我们将能够达到磁场强度(这里为1.5T)和角度(54.74o)的要求。有了这个磁铁，MAS核磁共振/核磁共振科学将首次拥有一个超导MAF磁铁，它可以产生强度显著的核磁共振质量磁场，例如1.5T&gt；&gt；36 Gauss(加州大学伯克利分校小组之前的最高值)，以持续模式运行。另一个值得注意的意义是将创新的低温设计应用于这种磁铁(也用于第二阶段)。磁体将浸泡在固体氮气(SN2)中，而不是在液氦(LHe)浴中操作。(在第二阶段，磁铁将被安置在一个将以6赫兹旋转的低温恒温器中。)这个全固态冷体改善了与LHe在旋转状态下相关的热流体问题。此外，冷体中Sn2的存在不仅确保整个绕组的温度更加均匀，而且还提供了大量的热质量，使磁体即使在主要冷却源(第一阶段中的LHe)关闭时也能在一段时间内保持其工作磁场。总之，这一分两个阶段的计划的成功完成将在MAS核磁共振/核磁共振科学领域开辟新的机遇，这反过来将为现代仪器分析开辟新的途径，最终导致用于分析、诊断和疾病预防的新型非侵入性生物医学工具。 公共卫生相关性：磁共振成像(MRI)和局部磁共振波谱(MRS)是一种非侵入性方法，用于研究与疾病相关的代谢变化，应用于检测、诊断、监测治疗进展和评估药物毒性。这项拟议的研究与公共健康相关，因为它承诺将MRI/MRS的能力扩展到高度不均匀磁化率的组织，如肺。它与美国国立卫生研究院的使命相关，因为它直接导致创新的研究战略和应用，最终将增强和改善人类健康。

DESCRIPTION (provided by applicant): Phase 1 of this 2-phase program has two specific aims: 1) successful completion of a magic-angle-field (MAF) magnet of a significant field strength with an NMR-quality field homogeneity for slow MAS (magic-angle-spinning) MRI/NMR; and 2) application and demonstration with the proposed system of an innovative cryogenic system suitable for a superconducting magnet spinning in Phase 1 slowly (~0.1 Hz) and in Phase 2 at 6 Hz. Unlike a conventional NMR or MRI magnet that has a field vector of NMR quality directed only in one axis, an MAF vector may be decomposed into two field vectors, one directed in one axis and the other in the direction normal to the first axis. The best, and perhaps the easiest, way to ensure an NMR-quality field directed at an angle of 54.74o from the magnet axis (also the rotation axis) is to ensure independently an NMR-quality field generated by each of the coils comprising an MAF magnet. This is the crux of our innovative design concept to build a successful superconducting MAF magnet: a combination of an axial z-field solenoid coil and an x-axis field dipole coil, each generating an NMR-quality field of a specific strength. By adjusting each coil's field strength, we will be able to achieve with this Phase 1 magnet both requirements of field strength (here 1.5 T) and angle (54.74o). With this magnet, for the very first time, MAS NMR/MRI sciences will have a superconducting MAF magnet that generates an NMR- quality field of significant strength, e.g., 1.5 T >> 36 gauss (the previous high by the UC Berkeley group), operated in persistent mode. Another notable significance is an innovative cryogenics design applied to this magnet (also to used in Phase 2). Instead of operated in a bath of liquid helium (LHe), the magnet will be immersed in solid nitrogen (SN2). (In phase 2,the magnet will be housed in a cryostat which will rotate at 6 Hz.) This all-solid cold body ameliorates thermo-fluid issues associated with LHe under rotation. Also, the presence of SN2 in the cold body not only ensures a more uniform temperature throughout the windings but also provides a large thermal mass, enabling the magnet to maintain its operating field over a time period even when the primarily cooling source (LHe in Phase 1) is shut off. In summary, the successful completion of this 2-phase program will open new opportunities in MAS NMR/MRI sciences, which in turn will open new avenues to modern instrumental analysis, ultimately leading to novel non-invasive biomedical tools for analysis, diagnosis, and disease prevention. PUBLIC HEALTH RELEVANCE: Magnetic Resonance Imaging (MRI) together with localized Magnetic Resonance Spectroscopy (MRS) is a non-invasive method for studying metabolic changes associated with diseases, with applications to detection, diagnosis, monitoring the progress of therapy, and evaluation of drug toxicity. The proposed research is relevant to public health since it promises to extend the capabilities of MRI/MRS to tissues with highly inhomogeneous magnetic susceptibility, such as lung. It is relevant to NIH's mission since it leads directly to innovative research strategies with applications which will ultimately enhance and improve human health.