A Novel Waveguide to Enable MAS-DNP-NMR in Standard-bore High-field Magnets

一种用于标准孔高场磁体MAS-DNP-NMR的新型波导 摘要 固态NMR（ssNMR）的关键重要性最近被证明，经过近二十年的研究， 激烈的努力，产生的第一个原子分辨率结构的A？40和A？42种淀粉样纤维， 在阿尔茨海默病（AD）中的作用。确定结构的关键是一种称为动态核技术的技术， 清晰偏振（DNP）和魔角旋转（MAS）。而低温EM，扫描隧道电子显微镜- 拷贝（STEM）和其他方法提供了有用的信息，MAS-NMR方法的最新进展提供了 必要的限制和额外的关键信息。因此，开发ssNMR的变革性进展 对结构生物学和生物医学研究都至关重要，对治疗阿尔茨海默病的进展至关重要， 缓解和癌症，并提供区域特异性药物结合信息，从而能够详细说明该机制 有效药物的作用。 到目前为止，MAS-DNP系统都需要专门的宽孔（WB）磁体，这主要是因为已知的非磁性磁体。 与太赫兹传输兼容的波导的迹象和各种相关问题不能被忽略 足以在用于标准孔（SB，也称为窄孔，NB）磁体的探头中工作。各专门 WB磁体和所需的波纹太赫兹波导构成了MAS的高成本的很大一部分。 DNP，这使得它遥不可及的所有，但一些一流的实验室。这项工作的第一阶段表明， 我们认为，这可以说是40-1500 GHz波导技术的最重大进展 半个世纪以来的波纹波导的发明范围。它们的衰减是两个数量级的磁- 在400 GHz下，其频率低于现有的小波导的频率，并且与非常昂贵的波纹波导的频率相当。 直径受到严格限制的波导。制造成本预计将远远超过订单 的数量级低于波纹波导，它们可以很容易地在直径足够小， 使MAS-DNP探针在现有NB高场磁体中实用。 这一拟议的第二阶段工作继续发展我们的革命性宽带层压衬波- 导轨（LLWG）和锥形过渡，用于40-1500 GHz范围，根据1.5-55 T NMR的需要。 预计这一进展，结合其他国家正在追求的其他几项技术进步， 项目，将使DNP被添加到现有的ssNMR高场系统，而不需要 专门的磁铁或回旋管。第二阶段的工作进一步提出了演示500 MHz NB HXY MAS的建议， 使用LLWG在50 K以下运行的DNP探头。LLWG的发展也将在以下方面得到重要应用： 超宽带6 G通信设备、下一代卫星通信、天体物理学和太赫兹医学成像方法。

A Novel Waveguide to Enable MAS-DNP-NMR in Standard-bore High-field Magnets Abstract The critical importance of solid-state NMR (ssNMR) was recently demonstrated by, after nearly two decades of intense efforts, yielding the first atomic-resolution structures of the A?40 and A?42 amyloid fibrils that play a crucial role in Alzheimer’s Disease (AD). Key to that structure determination was a technique denoted as dynamic nu- clear polarization (DNP) with magic angle spinning (MAS). While Cryo EM, scanning tunneling electron micros- copy (STEM) and other methods provided useful information, recent advances in MAS-NMR methods provided essential restraints and additional crucial information. Hence, developing transformational advances for ssNMR is crucial for both structural biology and biomedical research in general, for progress in curing Alzheimer’s Dis- ease and cancer, and for providing regio-specific drug binding information enabling detailing of the mechanism of action for effective drugs. MAS-DNP systems thus far have all required specialized wide-bore (WB) magnets largely because known de- signs of waveguides compatible with THz transmission and the various relevant issues cannot be made small enough to work in probes for use in standard-bore (SB, also called narrow-bore, NB) magnets. The specialized WB magnets and the required corrugated THz waveguides constitute a large portion of the high cost for MAS- DNP, which has put it out of reach to all but a few premiere laboratories. The Phase-I of this effort demonstrated what we believe can fairly be described as the most significant advance in waveguides for the 40-1500 GHz range in half a century – since the invention of corrugated waveguides. Their attenuation is two orders of mag- nitude below that of prior small waveguides at 400 GHz and comparable to that of the very expensive corrugated waveguides where the diameter is tightly constrained. Manufacturing costs are expected to be well over an order of magnitude below those of corrugated waveguides, and they can readily be made at diameters small enough to make MAS-DNP probes practical in existing NB high-field magnets. This proposed Phase II effort continues the development of our revolutionary broad-band Laminate-Lined Wave- Guides (LLWGs) and tapered transitions, for use over the 40-1500 GHz range, as needed for NMR at 1.5-55 T. It is expected that this advance, in combination with several other technological advances being pursued in other projects, will enable DNP to be added to existing ssNMR high-field systems without the requirement of either a specialized magnet or a gyrotron. This Phase-II effort further proposes to demonstrate a 500 MHz NB HXY MAS- DNP probe operating below 50 K utilizing LLWGs. The LLWG developments will also have major applications in ultra-broadband 6G communications equipment, next-gen satellite communications, astrophysics, and THz med-ical imaging methods.