We propose a program of research to design, build and operate a tunable 330 GHz gyrotron oscillator for CW DNP/NMR research. There are a number of 500/89 magnets in solid-state NMR laboratories around the world and these could be used with a 330 GHz microwave source to perform DNP/NMR. However, all of the known DNP mechanisms require that the magnetic field be adjusted to the peak of the enhancement curve to optimize the signal to noise ratio (S/N) of the experiment. This necessitates either that the magnetic field be swept with a sweep coil on the magnet, or that the microwave frequency be adjusted. In NMR systems using magnets with sweep coils, DNP/NMR research can be conducted with fixed frequency gyrotrons. However, the vast majority of NMR magnets in existence do not have sweep coils and it is impractical to retrofit these systems. Therefore, a tunable gyrotron oscillator appears to be the approach of choice for laboratories with this type of magnet. We propose to design and fabricate a 330 GHz gyrotron that can be tuned over a range of ?0.75 GHz which will permit coverage, for example, of the TEMPO EPR spectrum where the peaks in the enhancement curve will be separated by about 710 MHz. The tunable gyrotron oscillator will utilize a novel magnetic field tuning approach based on the excitation of high order axial modes of the resonator. Frequency tuning of ?0.9 GHz has been recently demonstrated on a 250 GHz gyrotron oscillator here at MIT. The gyrotron design will, in principle, be scalable to higher frequencies for application to 600 to 900 MHz where wide-bore magnets are currently available. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Research Project (R01)
Project #
5R01EB004866-02
Application #
7178519
Study Section
Special Emphasis Panel (ZRG1-BST-A (91))
Program Officer
Mclaughlin, Alan Charles
Project Start
2006-02-07
Project End
2009-11-30
Budget Start
2006-12-01
Budget End
2007-11-30
Support Year
2
Fiscal Year
2007
Total Cost
$437,727
Indirect Cost
Name
Massachusetts Institute of Technology
Department
Physics
Type
Schools of Arts and Sciences
DUNS #
001425594
City
Cambridge
State
MA
Country
United States
Zip Code
02139
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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