High Magnetic Field, Time Domain Magnetic Resonance Spectrometers

高磁场、时域磁共振波谱仪

• 批准号: 8876677
• 负责人: RICHARD J TEMKIN
• 金额: $ 39.12万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8876677
• 关键词: 2,4-Dinitrophenol; Amplifiers; Amyloid Proteins; Development; Electromagnetics; Electron Nuclear Double Resonance; Electron Spin Resonance Spectroscopy; Electrons; Frequencies; Goals; Health; Lead; Magic; Magnetic Resonance; Magnetism; Measurement; Membrane; Membrane Proteins; Methods; Motivation; Nuclear; Nuclear Magnetic Resonance; Output; Pattern; Phase; Physiologic pulse; Powder dose form; Process; Radiation; Relative (related person); Research; Research Design; Resolution; Role; Sampling; Signal Transduction; Solid; Source; Sterile coverings; Structure; System; Techniques; Technology; Time; Translating; Work; base; biological systems; cold temperature; cost; design; improved; instrumentation; magnetic field; microwave electromagnetic radiation; millimeter; nanosecond; novel; operation; photonics; research study; simulation software; solid state; transmission process

DESCRIPTION (provided by applicant): The proposed research is focused on the development of two separate time domain magnetic resonance spectrometers: one at a frequency of 140 GHz (1H frequency of 212 MHz, magnetic field of 5T) and the second at a frequency of 250 GHz (1H frequency of 380 MHz, magnetic field of 9T). These spectrometers will be the world's first high power time domain spectrometers operating at frequencies above 100 GHz where modern magnetic resonance experimental research is conducted. The application will be in time domain dynamic nuclear polarization/nuclear magnetic resonance (DNP/NMR) and EPR research. Currently, the full implementation of time domain magnetic resonance techniques at high frequency is restricted by the paucity of high frequency microwave amplifiers. The advent of high frequency microwave amplifiers will permit the development of polarization transfer methods based on coherent processes the integrated solid effect, the dressed state solid effect, electron-nuclear Hartmann-Hahn cross polarization, etc. -- which are more favorable at high magnetic fields. Gyroamplifiers are essential for the implementation of these time domain experiments. Time domain EPR spectroscopy will also benefit greatly from this new instrumentation. The higher frequency can offer increased g-factor resolution for spectra consisting of overlapping powder patterns, the more precise measurements of the relative orientation of g-, hyperfine and dipolar tensors, and it will further simplify the acquisition and interpretation of pulsed ENDOR spectra. Accordingly, the first goal of this proposal is to integrate an existing 820W, 140 GHz gyroamplifier with an existing NMR and EPR spectrometer and to obtain first demonstrations of the spectrometer in high power DNP/NMR and EPR research. We will use a versatile low temperature spectrometer designed for the study of DNP/NMR at 212 MHz and EPR at 140 GHz. We have recently successfully operated this spectrometer using a low power (120 mW) source, but must develop and implement the components needed for its use with the high power gyroamplifier source. The second goal is to design and demonstrate improved resonators for DNP/NMR and EPR, such as photonic crystal resonators, and to develop the necessary ancillary THz components for the NMR application, such as switches, circulators, transmission lines, etc. for THz DNP/NMR and EPR experiments. Because of the scarcity and high cost of commercial instrumentation at high frequencies, it is crucial to develop these components to efficiently transmit and apply the available coherent radiation. The third specific aim is to complete the development of an existing 14 W, 250 GHz gyroamplifier and to apply that amplifier to pulsed DNP/NMR and EPR research. We first plan to finish the development of this amplifier at a power level of > 100 W using improved gyroamplifier designs in the first year of the proposal. Once the 250 GHz gyroamplifier is fully developed, we will apply it to pulsed DNP/NMR and EPR. The resultant system will then be the highest frequency high power DNP/NMR and EPR spectrometer in the world.

描述（由申请人提供）：拟议的研究重点是开发两台独立的时域磁共振波谱仪：一台频率为 140 GHz（1H 频率为 212 MHz，磁场为 5T），第二台频率为250 GHz（1H频率380 MHz，磁场9T）。这些光谱仪将是世界上第一台工作频率高于 100 GHz 的高功率时域光谱仪，可用于现代磁共振实验研究。该应用将用于时域动态核极化/核磁共振 (DNP/NMR) 和 EPR 研究。目前，高频时域磁共振技术的全面实施受到高频微波放大器缺乏的限制。高频微波放大器的出现将允许基于相干过程的偏振传输方法的发展，集成固体效应、修饰态固体效应、电子核哈特曼-哈恩交叉极化等——这在高磁力下更有利字段。陀螺放大器对于实施这些时域实验至关重要。时域 EPR 光谱也将从这种新仪器中受益匪浅。更高的频率可以为由重叠粉末图案组成的光谱提供更高的 g 因子分辨率，更精确地测量 g-、超精细和偶极张量的相对方向，并将进一步简化脉冲 ENDOR 光谱的采集和解释。因此，该提案的首要目标是将现有的 820W、140 GHz 陀螺放大器与现有的 NMR 和 EPR 波谱仪集成，并在高功率 DNP/NMR 和 EPR 研究中获得波谱仪的首次演示。我们将使用专为研究 212 MHz 的 DNP/NMR 和 140 GHz 的 EPR 而设计的多功能低温光谱仪。我们最近成功地使用低功率（120 mW）源操作了该光谱仪，但必须开发和实现与高功率陀螺放大器源一起使用所需的组件。第二个目标是设计和演示用于 DNP/NMR 和 EPR 的改进谐振器，例如光子晶体谐振器，并开发用于 NMR 应用的必要辅助太赫兹组件，例如用于太赫兹 DNP 的开关、环行器、传输线等/NMR 和 EPR 实验。由于高频商用仪器的稀缺性和高成本，开发这些组件以有效传输和应用可用的相干辐射至关重要。第三个具体目标是完成现有 14 W、250 GHz 陀螺放大器的开发，并将该放大器应用于脉冲 DNP/NMR 和 EPR 研究。我们首先计划在提案的第一年使用改进的陀螺放大器设计完成功率水平 > 100 W 的放大器的开发。一旦250 GHz陀螺放大器完全开发出来，我们将把它应用于脉冲DNP/NMR和EPR。由此产生的系统将成为世界上频率最高的高功率 DNP/NMR 和 EPR 波谱仪。