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

这个两阶段计划的第一阶段有两个具体目标：1）成功完成一个 具有NMR质量磁场的显著磁场强度的魔角场（MAF）磁体 慢MAS（魔角旋转）MRI/NMR的均匀性;以及2）应用和 用所提出的系统演示一种创新的低温系统， 超导磁体在相位1中缓慢旋转（~ 0.1Hz），在相位2中以6 Hz旋转。 与具有NMR质量的场矢量的常规NMR或MRI磁体不同， 仅在一个轴上定向，MAF矢量可以被分解成两个场矢量，一个场矢量是 沿一个轴定向，而另一个沿垂直于第一轴的方向定向。最好的， 也许是最简单的方法，以确保核磁共振质量的领域指向的角度为54.74 从磁体轴（也是旋转轴）的角度独立地确保NMR质量 由包括MAF磁体的每个线圈产生的磁场。这是我们的症结所在。 一个成功超导MAF磁体的创新设计概念： 轴向z场螺线管线圈和x轴场偶极线圈的组合，每个 产生特定强度的NMR质量场。通过调整每个线圈的磁场 强度，我们将能够实现这一阶段1磁铁场的要求 强度（此处为1.5 T）和角度（54.74 o）。有了这个磁铁，第一次，MAS NMR/MRI科学将有一个超导MAF磁铁，产生一个NMR- 具有显著强度的质量场，例如，1.5 T >> 36高斯（UC之前的最高值 Berkeley组），以持久模式运行。另一个值得注意的意义是 创新的低温设计应用于该磁体（也用于第2阶段）。相反 在液氦（LHe）浴中操作，磁体将浸入固体中， 氮（SN 2）。(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.）这种全固体冷体改善了在低温下与LHe相关的热流体问题。 旋转此外，在冷体中存在SN 2不仅确保了更均匀的热稳定性， 温度，而且还提供了大的热质量， 磁体在一段时间内保持其工作磁场，即使当主要 关闭冷却源（阶段1中的LHe）。总而言之， 这两个阶段的计划将打开新的机会，在MAS NMR/MRI科学， 这一转变将为现代仪器分析开辟新的途径，最终导致新颖的 用于分析、诊断和疾病预防的非侵入性生物医学工具。

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.