Dynamic nuclear polarization at 9 T using a novel 250 GHz gyrotron microwave source
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Griffin_Dynamic nuclear polarization.pdf
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Author(s)
Bajaj, Vikram S.
Farrar, C. T.
Hornstein, Melissa K.
Mastovsky, Ivan
Vieregg, Jeffrey
Bryant, Jeffrey A.
Elena, B.
Kreischer, K. E.
Griffin, Robert Guy
Temkin, Richard J
Date Issued
December 2011
Journal
Journal of Magnetic Resonance
Publisher
Elsevier
Citation
Bajaj, V.S., C.T. Farrar, M.K. Hornstein, I. Mastovsky, J. Vieregg, J. Bryant, B. Eléna, K.E. Kreischer, R.J. Temkin, and R.G. Griffin. “Dynamic Nuclear Polarization at 9T Using a Novel 250GHz Gyrotron Microwave Source.” Journal of Magnetic Resonance 213, no. 2 (December 2011): 404–409.
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Author's final manuscript
Abstract
In this communication, we report enhancements of nuclear spin polarization by dynamic nuclear polarization (DNP) in static and spinning solids at a magnetic field strength of 9 T (250 GHz for g = 2 electrons, 380 MHz for [superscript 1]H). In these experiments, [superscript 1]H enhancements of up to 170 ± 50 have been observed in 1-[superscript 13]C-glycine dispersed in a 60:40 glycerol/water matrix at temperatures of 20 K; in addition, we have observed significant enhancements in [superscript 15]N spectra of unoriented pf1-bacteriophage. Finally, enhancements of ~17 have been obtained in two-dimensional [superscript 13]C–[superscript 13]C chemical shift correlation spectra of the amino acid U–[superscript 13]C, [superscript 15]N-proline during magic angle spinning (MAS), demonstrating the stability of the DNP experiment for sustained acquisition and for quantitative experiments incorporating dipolar recoupling. In all cases, we have exploited the thermal mixing DNP mechanism with the nitroxide radical 4-amino-TEMPO as the paramagnetic dopant. These are the highest frequency DNP experiments performed to date and indicate that significant signal enhancements can be realized using the thermal mixing mechanism even at elevated magnetic fields. In large measure, this is due to the high microwave power output of the 250 GHz gyrotron oscillator used in these experiments.
MIT Department
Massachusetts Institute of Technology. Department of Chemistry
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Plasma Science and Fusion Center
Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology)
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DOI of Published Version
https://doi.org/10.1016/j.jmr.2011.09.010
