250/500 GHZ GYROTRON BASED DNP/EPR SPECTROMETER

描述：这是Kreischer博士和 他的同事(麻省理工学院的Temkin博士和Griffin博士)开发了一种动态核技术 极化(DNP)增强型核磁共振谱仪将工作在254 GHz电子频率 辐照频率(约9特斯拉磁场和380 MHz质子核磁共振 频率)和254千兆赫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。 稍后，将努力将电子频率增加一倍，达到508 GHz 通过产生谐波，以开发出真正的高场 DNP增强型核磁共振波谱仪。 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展示了一种50倍的DNP 来自氮-15标记蛋白质的氮-15核磁共振信号的增强， T4溶菌酶，较高的磁场会产生更强的 来自蛋白质的更高分辨率的核磁共振信号，有望实现迄今不可能的核磁共振 生物大分子与分子的结构/功能研究 体重超过10万。将开发新的9特斯拉DNP/核磁共振光谱仪 被视为现有5特斯拉系统的最终替代品。 254 GHz电子顺磁共振波谱仪的基本原理是140 GHz电子顺磁共振 格里芬教授实验室的实验证明， 利用提供的优秀塞曼分辨率的实际优势 用高场电子顺磁共振解决有趣而重要的生化问题 在许多情况下，延伸到更高的领域将甚至 更多信息。新的254 GHz EPR光谱仪计划作为 这是对目前140 GHz光谱仪的补充，而不是替代。 为了构建DNP仪器，一种新型的紧凑型254 GHz 100瓦信号源 必须首先开发毫米波辐射。 拟议的EPR仪器将使用5英寸直径9.4T的核磁共振磁体和2T 可扫描的场，并具有带有耿氏二极管的连续外差反射电桥 准光环行器、波纹波导、低温光源 杜瓦和圆柱形谐振器。 拟议的DNP/核磁共振光谱仪将包括一个低温 魔角旋转探头并将毫米波功率传输到 通过低损耗波纹波导进行采样。

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.