140 GHz Gyroamplifier for Time Domain DNP and EPR

描述（申请者提供）：我们拟设计并建造一个100w， 140ghz的回旋管放大器，并将其应用于时域DNP/NMR和EPR实验。在过去十年中，利用90-300千兆赫频段的高频微波的时域磁共振技术已经大大扩大。具体来说，时域EPR和DNP/NMR实验已经成为阐明生物系统结构、功能和动态特性的重要技术。然而，目前这些技术在高频下的全面实施受到微波功率不足的限制。该提案要求资助开发工作频率为140 GHz、带宽为1 GHz、饱和增益为35 dB的高功率回旋管放大器。回旋管放大器特别有吸引力，因为它能够扩展到更高的频率。低功率（30- 60mw）相开关和脉冲形成网络（具有四相和< 1ns开关能力）将用作陀螺仪放大器的输入（驱动器）。该陀螺放大器将使最近开发的电子-核交叉极化（CP）实验得以全面实施，并将最近开发的低频（9-18 GHz）脉冲EPR技术扩展到高频，用于测量自旋标记生物系统中的长距离（15-80埃）电子-电子偶极耦合。综上所述，本研究的具体目的可分为三个部分：

DESCRIPTION (provided by applicant): We propose to design and build a 100 W, 140 GHz gyrotron amplifier and to apply it in time domain DNP/NMR and EPR experiments. During the last decade the repertoire of time domain magnetic resonance techniques that utilize high frequency microwaves in the 90-300 GHz regime has expanded considerably. Specifically, time domain EPR and DNP/NMR experiments have emerged as important techniques for elucidating the structure, function, and dynamic properties of biological systems. However, at present the full implementation of these techniques at high frequency is limited by the lack of microwave power. This proposal requests funding to develop a high power gyrotron amplifier operating at 140 GHz with a 1 GHz bandwidth and 35 dB of saturated gain. A gyrotron amplifier is particularly attractive because it is capable of extension to higher frequency. A low power (30-60 mW) phase switching and pulse forming network (with four phase and <1 ns switching capability) will be used as the input (driver) for the gyro-amplifier. This gyro-amplifier will enable the full implementation of a recently developed electron-nuclear crosspolarization (CP) experiment and the extension to high frequency of recently developed low frequency (9-18 GHz) pulsed EPR techniques for measuring long range (15-80Angstroms) electron-electron dipolar couplings in spin labeled biological systems. To summarize, the specific aims of the research can be divided into three parts: (1) Development of a 100 W, high frequency (140 GHz) gyrotron amplifier. (2) Implementation of electron-nuclear CP experiments with BDPA/PS and trityl/water glycerol samples. (3) Implementation of multiple quantum and SIFTER pulsed EPR experiments at 140 GHz using biradical spin labeled peptides.