Compact Pulse Slicer for High-Power Submillimeter Waves

项目摘要/摘要 复杂的生物大分子，如膜蛋白，在许多细胞和 生理过程和特定的缺陷与许多已知的疾病有关。确定了他们的三个- 空间结构是结构生物学的主要目标之一，美国国立卫生研究院致力于 为实现这一目标提供资源。X射线结晶学和核磁共振光谱是这种现象的主要来源 信息。此外，电子顺磁共振(EPR)谱，特别是偶极 光谱学(PELDOR/DER/RIDME)是补充准确距离信息的宝贵来源 结构测定的其他方法。然而，由于核磁共振固有的低灵敏度， 小的核磁矩。需要较长的采集时间才能获得足够的数据质量。组合 具有动态核极化(DNP)的核磁共振是克服这一限制的一种很好的方法，它提高了灵敏度和 将采集时间缩短了几个数量级。近年来的DNP增强核磁共振波谱 已经成为核磁共振光谱学家工具箱中不可或缺的一部分，因为这种方法使研究人员能够 进行以前不可能完成的实验。 虽然DNP可以极大地提高核磁共振实验的灵敏度，但该方法的规模非常大 不利于磁场强度，导致在较高磁场下较低的增强值。 这对于所有基于样品的连续波(CW)辐射的DNP机制都是常见的。脉冲DNP 另一方面，实验并没有显示出这种行为。然而，创造/塑造的常见方法 低功率(~mW)的脉冲和放大它们(&gt；10-100 W)无法工作，因为缺少高功率- 功率/高频微波/太赫兹放大器。 在此SBIR应用中，我们建议开发一种紧凑的、交钥匙脉冲限幅器，以产生短、高、 来自DNP-核磁共振实验中常用的回旋管等连续波源的功率脉冲。这个 即使对于非微波工程师来说，系统也很容易操作，并且可以很容易地集成到现有的 设置。 该脉搏切片器的成功开发将为 否则只能在CW模式下运行的系统。这将极大地促进该方法的发展，并具有重大意义。 对许多由美国国立卫生研究院资助的项目感兴趣。

Project Summary / Abstract Complex bio-macromolecules such as membrane proteins play crucial roles in many cellular and physiological processes and specific defects are associated with many known. Determining their three- dimensional structures is one of the main objectives in structural biology and the NIH devotes considerable resources towards this goal. X-ray crystallography and NMR spectroscopy are the major sources for such information. In addition, Electron Paramagnetic Resonance (EPR) spectroscopy, in particular dipolar spectroscopy (PELDOR/DEER/RIDME) is a valuable source for accurate distance information to complement other methods for structure determination. However, NMR suffers from an inherently low sensitivity due to the small nuclear magnetic moment. Long acquisition times are required to achieve sufficient data quality. Combining NMR with Dynamic Nuclear Polarization (DNP) is a great way to overcome this limit, boosting sensitivity and shortening acquisition times by several orders of magnitude. In recent years DNP-enhanced NMR spectroscopy has become an integral part of the NMR spectroscopists toolbox, because the method enables researchers to perform experiments that were previously not possible. While DNP can increase the sensitivity of an NMR experiment drastically, the methodology scales very unfavorably with the magnetic field strength, leading to lower enhancement values at higher magntice fields. This is common to all DNP mechanisms based on continuous wave (cw) radiation of the sample. Pulsed DNP experiments on the other hand do not show this behavior. However, the common approach of creating/shaping pulses at low powers (~ mW) and amplifying them (> 10-100 W) does not work because of the lack of high- power/high-frequency microwave/THz amplifiers. In this SBIR application we propose to develop a compact, turn-key pulse slicer to generate short, high- power pulses from cw sources such as gyrotrons, that are commonly used in DNP-NMR experiments. The system will be easy to operate even for non-microwave engineers and can be readily integrated into existing setups. The successful development of this pulse slicer will bring desperately needed pulse capabilities to systems that otherwise can only be operated in cw mode. This will greatly proliferate the method and is of large interest to many projects funded by the U.S. National Institutes of Health.