Diamond Rotors

项目摘要 本方案的研究重点是开发制作魔角的方法。 单晶金刚石原木旋压(MAS)转子，用于(1)常温MAS (2)动态核极化(DNP)MAS实验。特别是，有一种前所未有的- 增加对获得更高旋转频率的转子的推动，以提高MAS核磁共振的性能 敏感度和分辨率。然而，目前可获得的旋转频率(~100 kHz)受到以下限制 制造转子的材料的强度--通常是抗弯强度为 ~800兆帕。当频率超过~120 kHZ时，氧化锆转子发生爆炸。钻石是地球上最坚固的材料之一 单晶样品的抗弯强度为2-5 Gpa，因此是制造的理想材料 MAS转子。此外，钻石对太赫兹辐射是透明的，因此它是DNP实验的理想材料。 最后，它具有优异的热性能--它的导热系数是铜的10倍。因此，很容易 补偿与MAS相关的气动加热。将金刚石圆柱体加工到高 转子的公差要求需要一种新的激光加工工艺，我们已经开始开发这种工艺 生产小型(≤外径1.3 mm)钻石转子。在这里，我们建议改进我们的流程并在我们的 可用的仪器。目标是生产1.3毫米、0.7毫米和新一代0.5毫米转子 这将达到ωr/2π&gt；300 khz，并将MAS光谱的分辨率提高约5倍 目前可用。此外，我们预计钻石转子将带来更大的DNP增强。 我们还描述了一些在淀粉样纤维和膜蛋白方面的应用，我们预计 钻石转子将产生重大的科学影响。

Project Summary The research in this proposal focuses on the development of methods for fabricating magic-angle spinning (MAS) rotors from single crystal diamond logs for applications (1) in ambient temperature MAS experiments, and (2) dynamic nuclear polarization (DNP) MAS experiments. In particular, there is an ever- increasing push towards rotors that attain higher spinning frequencies for MAS NMR in order to improve sensitivity and resolution. However, the spinning frequencies currently obtainable (~100 kHz) are limited by the strength of the material from which the rotors are fabricated – typically ZrO2 with flexural strength of ~800 MPa. Above ~120 kHz the ZrO2 rotors explode. Diamond is one of the strongest materials on earth with flexural strengths of 2-5 GPa for single crystal samples and therefore an ideal material to manufacture MAS rotors. Furthermore, diamond is transparent to terahertz radiation, so it is ideal for DNP experiments. Finally, it has excellent thermal properties – it thermal conductivity is 10x better than Cu. Thus, it is easy to compensate for the aerodynamic heating associated with MAS. Machining diamond cylinders to high tolerance required for rotors requires a novel laser machining processes which we have begun to develop to produce small (≤1.3 mm OD) diamond rotors. Here we propose to refine our processes and test them in our available instrumentation. The goal is to produce 1.3 mm, 0.7 mm and a new generation of 0.5 mm rotors that will attain ωr/2π>300 kHz and improve the resolution of MAS spectra by a factor of ~5 over what is currently available. In addition, we anticipate that diamond rotors will lead to larger DNP enhancements. We also describe some applications to amyloid fibrils and membrane proteins where we anticipate that diamond rotors will have a significant scientific impact.