Diamond Rotors

项目摘要 本计画的研究重点在于发展魔角的制作方法 用于（1）室温MAS的单晶金刚石原木的旋转（MAS）转子 动态核极化（DNP）MAS实验。特别是，有一个永远- 增加对转子的推动，以获得MAS NMR的更高旋转频率， 灵敏度和分辨率。然而，目前可获得的旋转频率（~100 kHz）受到以下因素的限制： 制造转子的材料的强度-通常为具有100%的抗弯强度的ZrO 2， ~800 MPa。高于~120 kHz时，ZrO 2转子爆炸。钻石是地球上最坚固的材料之一 单晶样品的弯曲强度为2-5 GPa，因此是理想的制造材料 MAS转子。此外，金刚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-它的热导率比Cu好10倍。因此， 补偿与MAS相关的气动加热。加工金刚石圆柱体高 转子所需的公差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）金刚石转子。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毫米旋翼 这将达到ωr/2π>300 kHz，并将MAS光谱的分辨率提高约5倍， 目前可用。此外，我们预计金刚石转子将导致更大的DNP增强。 我们还描述了淀粉样纤维和膜蛋白的一些应用，我们预计， 金刚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.