High Magnetic Field, Time Domain Magnetic Resonance Spectrometers

描述（由申请人提供）：拟定研究的重点是开发两种单独的时域磁共振光谱仪：一种频率为140 GHz（1H频率为212 MHz，磁场为5 T），另一种频率为250 GHz（1H频率为380 MHz，磁场为9 T）。这些光谱仪将是世界上第一台在100 GHz以上频率工作的高功率时域光谱仪，用于进行现代磁共振实验研究。应用将在时域动态核极化/核磁共振（DNP/NMR）和EPR研究。目前，时域磁共振技术在高频的全面实施受到高频微波放大器的缺乏的限制。高频微波放大器的出现将使基于相干过程的极化转移方法得以发展，这些相干过程包括积分固体效应、缀饰态固体效应、电子-核Hartmann-Hahn交叉极化等，这些方法在高磁场下更有利。陀螺放大器是必不可少的实施这些时域实验。时域EPR光谱也将大大受益于这种新的仪器。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，g-，超精细和偶极张量的相对取向的更精确测量，并且它将进一步简化脉冲ENDOR光谱的采集和解释。因此，本提案的第一个目标是将现有的820 W，140 GHz陀螺放大器与现有的NMR和EPR光谱仪集成，并在高功率DNP/NMR和EPR研究中获得光谱仪的首次演示。我们将使用一个多功能的低温光谱仪设计的DNP/NMR在212 MHz和EPR在140 GHz的研究。我们最近成功地操作这个光谱仪使用低功率（120毫瓦）源，但必须开发和实施的组件需要使用高功率陀螺放大器源。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THz组件，例如用于THz DNP/NMR和EPR实验的开关，环行器，传输线等。由于高频商业仪器的稀缺性和高成本，开发这些组件以有效地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的14 W，250 GHz陀螺放大器的发展，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仪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光谱仪。

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.