250/500 GHZ GYROTRON BASED DNP/EPR SPECTROMETER

250/500 GHZ 基于回旋管的 DNP/EPR 光谱仪

• 批准号: 2655031
• 负责人: KENNETH E KREISCHER
• 金额: $ 51.47万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-02-01 至 2000-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2655031
• 关键词: bioengineering /biomedical engineering; computer program /software; electron spin resonance spectroscopy; microwave radiation; nuclear magnetic resonance spectroscopy

DESCRIPTION: This is an instrumentation proposal by Dr. Kreischer and colleagues (Drs. Temkin and Griffin at MIT) to develop a dynamic nuclear polarization (DNP) enhanced NMR spectrometer to operate at 254 GHz electron irradiation frequency (about 9 Tesla magnetic field and 380 MHz proton NMR frequency) and a 254 GHz electron paramagnetic resonance spectrometer. These instruments will share many components and assemblies in common. Later, there will be an effort to double the electron frequency to 508 GHz through harmonic generation in order to develop a truly high-field DNP-enhanced NMR spectrometer. The rationale for this DNP instrument is that 5T (140 GHz) DNP experiments in Professor Griffin's laboratory have demonstrated a 50-fold DNP enhancement of nitrogen-15 NMR signals from a nitrogen-15-labeled protein, T4 lysozyme, and that higher magnetic fields will give even stronger and better-resolved NMR signals from proteins, promising hitherto impossible NMR structure/function studies on biological macromolecules with molecular weights over 100,000. The new 9 Tesla DNP/NMR spectrometer to be developed is seen as an eventual replacement for the existing 5 Tesla system. The rationale for the 254 GHz EPR spectrometer is that 140 GHz EPR experiments in Professor Griffin's laboratory have demonstrated the practical advantages of exploiting the excellent Zeeman resolution afforded by high-field EPR to solve interesting and important biochemical problems and that in many cases, an extension to even higher fields will give even more information. The new 254 GHz EPR spectrometer is planned as a complement to, not a replacement for, the current 140 GHz spectrometer. To construct the DNP instrument, a new compact 100-watt source of 254 GHz millimeter-wave radiation must first be developed. The proposed EPR instrument will use a 5-inch-bore 9.4T NMR magnet with a 2T sweepable field and have a CW heterodyne reflection bridge with Gunn diode sources, quasi-optic circulator, corrugated waveguide, low-temperature Dewar, and cylindrical resonators. The proposed DNP/NMR spectrometer will incorporate a low-temperature magic-angle-spinning probe and transmit the millimeter-wave power to the sample through low-loss corrugated waveguide.

描述：这是Kreischer博士的仪器建议， 同事（麻省理工学院的Temkin和Griffin博士）开发了一种动态核动力学。 极化（DNP）增强NMR光谱仪，在254 GHz电子 辐照频率（约9特斯拉磁场和380 MHz质子NMR 频率）和254 GHz电子顺磁共振光谱仪。 这些仪器将共享许多共同的部件和组件。 之后，将努力将电子频率加倍至508 GHz 通过谐波产生，以开发一个真正的高场 DNP增强核磁共振光谱仪。 该DNP仪器的基本原理是5T（140 GHz）DNP实验 在格里芬教授的实验室里已经证明了50倍的DNP 增强来自氮-15-标记的蛋白质的氮-15 NMR信号， T4溶菌酶，更高的磁场会产生更强的， 来自蛋白质的更好分辨的NMR信号，有望实现迄今为止不可能的NMR 生物大分子结构与功能研究 重量超过10万 即将开发的新型9特斯拉DNP/NMR光谱仪 它被认为是现有5特斯拉系统的最终替代品。 254 GHz EPR光谱仪的原理是140 GHz EPR 格里芬教授实验室的实验表明， 利用优秀的塞曼分辨率提供的实际优势 通过高场EPR来解决有趣和重要的生物化学问题 而且在许多情况下，扩展到更高的领域， 更多信息 新的254 GHz EPR光谱仪计划作为 补充，而不是取代，目前的140千兆赫频谱仪。 为了构建DNP仪器，一个新的254 GHz的紧凑型100瓦源 必须首先开发毫米波辐射。 拟议的EPR仪器将使用5英寸口径的9.4T NMR磁体， 具有带古恩二极管CW外差反射桥 光源，准光环行器，波纹波导，低温 杜瓦瓶和圆柱形谐振器。 拟议的DNP/NMR光谱仪将采用低温 魔角旋转探头，并将毫米波功率传输到 样品通过低损耗波纹波导。