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

描述（由申请人提供）：该2阶段计划的第1阶段有两个具体目标：1）成功完成具有显著场强的魔角场（MAF）磁体，其具有用于缓慢MAS的NMR质量场均匀性（魔角旋转）MRI/NMR;和2）第一阶段中适用于超导磁体自旋的创新低温系统的应用和演示缓慢地（~0.1 Hz）和在阶段2中以6 Hz。与具有仅指向一个轴的NMR质量的场矢量的常规NMR或MRI磁体不同，MAF矢量可以被分解成两个场矢量，一个场矢量指向一个轴，另一个场矢量指向垂直于第一轴的方向。确保NMR质量场指向与磁体轴（也是旋转轴）成54.74 °角的最佳且可能是最简单的方法是独立地确保由包括MAF磁体的每个线圈产生的NMR质量场。这是我们构建成功的超导MAF磁体的创新设计理念的关键：轴向z场螺线管线圈和x轴场偶极线圈的组合，每个线圈都产生特定强度的NMR质量场。通过调整每个线圈的磁场强度，我们将能够使用该阶段1磁体实现磁场强度（此处为1.5 T）和角度（54.74 o）的要求。有了这个磁体，MAS NMR/MRI科学将首次拥有超导MAF磁体，该磁体可产生具有显著强度的NMR质量场，例如，1.5 T >> 36高斯（加州大学伯克利分校小组的前一个高值），以持续模式运行。另一个值得注意的意义是应用于该磁体的创新低温设计（也用于第2阶段）。磁体将浸入固体氮（SN 2）中，而不是在液氦（LHe）浴中操作。(In阶段2，磁体将被容纳在低温恒温器中，该低温恒温器将以6 Hz旋转。这种全固体冷体改善了与旋转下的LHe相关的热流体问题。此外，在冷体中存在SN 2不仅确保了整个绕组的更均匀的温度，而且还提供了大的热质量，使得磁体能够在一段时间内保持其操作场，即使当主要冷却源（阶段1中的LHe）被关闭时。总之，这两个阶段计划的成功完成将为MAS NMR/MRI科学开辟新的机会，这反过来又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）与局部磁共振波谱（MRS）一起是用于研究与疾病相关的代谢变化的非侵入性方法，其应用于检测、诊断、监测治疗进展和评价药物毒性。拟议的研究与公共卫生有关，因为它有望将MRI/MRS的能力扩展到具有高度不均匀磁化率的组织，如肺。它与国家卫生研究院的使命有关，因为它直接导致创新的研究战略，其应用将最终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.