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.
| Nanni, Emilio A; Jawla, Sudheer; Lewis, Samantha M et al. (2017) Photonic-band-gap gyrotron amplifier with picosecond pulses. Appl Phys Lett 111:233504 |
| Soane, Alexander V; Shapiro, Michael A; Jawla, Sudheer et al. (2017) Operation of a 140 GHz Gyro-amplifier using a Dielectric-loaded, Sever-less Confocal Waveguide. IEEE Trans Plasma Sci IEEE Nucl Plasma Sci Soc 45:2835-2840 |
| Ni, Qing Zhe; Yang, Fengyuan; Can, Thach V et al. (2017) In Situ Characterization of Pharmaceutical Formulations by Dynamic Nuclear Polarization Enhanced MAS NMR. J Phys Chem B 121:8132-8141 |
| Soane, Alexander V; Shapiro, Michael A; Stephens, Jacob C et al. (2017) Theory of Linear and Nonlinear Gain in a Gyroamplifier using a Confocal Waveguide. IEEE Trans Plasma Sci IEEE Nucl Plasma Sci Soc 45:2438-2449 |
| Schaub, S C; Shapiro, M A; Temkin, R J (2016) Simple Expressions for the Design of Linear Tapers in Overmoded Corrugated Waveguides. J Infrared Millim Terahertz Waves 37:100-110 |
| Kowalski, Elizabeth J; Shapiro, Michael A; Temkin, Richard J (2014) Simple Correctors for Elimination of High-Order Modes in Corrugated Waveguide Transmission Lines. IEEE Trans Plasma Sci IEEE Nucl Plasma Sci Soc 42:29-37 |
| Michaelis, Vladimir K; Ong, Ta-Chung; Kiesewetter, Matthew K et al. (2014) Topical Developments in High-Field Dynamic Nuclear Polarization. Isr J Chem 54:207-221 |
| Jawla, Sudheer K; Shapiro, Michael A; Idei, Hiroshi et al. (2014) Corrugated Waveguide Mode Content Analysis Using Irradiance Moments. IEEE Trans Plasma Sci IEEE Nucl Plasma Sci Soc 42:3358-3364 |
| Lewis, Samantha M; Nanni, Emilio A; Temkin, Richard J (2014) Direct Machining of Low-Loss THz Waveguide Components With an RF Choke. IEEE Microw Wirel Compon Lett 24:842-844 |
| Jawla, Sudheer; Ni, Qing Zhe; Barnes, Alexander et al. (2013) Continuously Tunable 250 GHz Gyrotron with a Double Disk Window for DNP-NMR Spectroscopy. J Infrared Millim Terahertz Waves 34:42-52 |
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