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

描述（由申请人提供）：这个两阶段项目的第一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，并具有核磁共振质量场均匀性，用于慢速MAS（魔角旋转）MRI/NMR；2)应用和演示了一种创新的低温系统，该系统适用于超导磁体在第1阶段（~0.1 Hz）缓慢旋转和第2阶段以6 Hz旋转。与传统的核磁共振或核磁共振磁体不同，核磁共振质量的场矢量只指向一个轴，MAF矢量可以分解为两个场矢量，一个指向一个轴，另一个指向与第一个轴垂直的方向。确保核磁共振质量场与磁体轴（也是旋转轴）成54.74°角的最佳，也许也是最简单的方法是确保每个包含MAF磁体的线圈独立产生核磁共振质量场。这是我们创新设计理念的关键，以建立一个成功的超导MAF磁铁：轴向z场电磁线圈和x轴场偶极子线圈的组合，每个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，我们将能够实现第1阶段磁体的磁场强度（这里为1.5 T）和角度（54.74o）的要求。有了这个磁体，MAS核磁共振/核磁共振科学将首次拥有一个超导MAF磁体，它可以产生显著强度的核磁共振质量场，例如1.5 T >> 36高斯（加州大学伯克利分校小组之前的最高强度），并在持续模式下运行。另一个值得注意的意义是应用于该磁体的创新低温设计（也用于第二阶段）。磁铁不是在液氦（LHe）浴中操作，而是浸泡在固体氮（SN2）中。（在第二阶段，磁体将被安置在低温恒温器中，该低温恒温器将以6赫兹的速度旋转。）这种全固体冷体改善了旋转下与LHe相关的热流体问题。此外，冷体中SN2的存在不仅确保了整个绕组的温度更加均匀，而且还提供了大的热质量，即使在主要冷却源（阶段1中的LHe）关闭时，也能使磁铁在一段时间内保持其工作场。总之，这两阶段计划的成功完成将为MAS NMR/MRI科学开辟新的机遇，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。

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.