An increase in Dynamic Nuclear Polarization (DNP) signal intensity is obtained with a tunable gyrotron producing frequency modulation around 260GHz at power levels less than 1W. The sweep rate of frequency modulation can reach 14kHz, and its amplitude is fixed at 50MHz. In water/glycerol glassy ice doped with 40mM TEMPOL, the relative increase in the DNP enhancement was obtained as a function of frequency-sweep rate for several temperatures. A 68 % increase was obtained at 15K, thus giving a DNP enhancement of about 80. By employing lambda/4 and lambda/8 polarizer mirrors, we transformed the polarization of the microwave beam from linear to circular, and achieved an increase in the enhancement by a factor of about 66% for a given power.
Dynamic nuclear polarization by frequency modulation of a tunable gyrotron of 260GHz
From The DNP-NMR Blog:
Dynamic nuclear polarization by frequency modulation of a tunable gyrotron of 260GHz
Yoon, D., et al., Dynamic nuclear polarization by frequency modulation of a tunable gyrotron of 260GHz. J Magn Reson, 2016. 262: p. 62-7.
http://www.ncbi.nlm.nih.gov/pubmed/26759116
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03-22-2016 01:14 AM
Microwave frequency modulation to enhance Dissolution Dynamic Nuclear Polarization
From The DNP-NMR Blog:
Microwave frequency modulation to enhance Dissolution Dynamic Nuclear Polarization
Bornet, A., et al., Microwave frequency modulation to enhance Dissolution Dynamic Nuclear Polarization. Chem. Phys. Lett., 2014. 602: p. 63-67.
http://www.sciencedirect.com/science/article/pii/S0009261414002826
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01-04-2016 07:49 PM
Microwave frequency modulation to enhance Dissolution Dynamic Nuclear Polarization
From The DNP-NMR Blog:
Microwave frequency modulation to enhance Dissolution Dynamic Nuclear Polarization
Bornet, A., J. Milani, B. Vuichoud, A.J. Perez Linde, G. Bodenhausen, and S. Jannin, Chem. Phys. Lett., 602, (2014)
http://www.sciencedirect.com/science/article/pii/S0009261414002826
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12-28-2015 12:26 AM
High-Speed Frequency Modulation of a 460-GHz Gyrotron for Enhancement of 700-MHz DNP-NMR Spectroscopy
From The DNP-NMR Blog:
High-Speed Frequency Modulation of a 460-GHz Gyrotron for Enhancement of 700-MHz DNP-NMR Spectroscopy
Idehara, T., et al., High-Speed Frequency Modulation of a 460-GHz Gyrotron for Enhancement of 700-MHz DNP-NMR Spectroscopy. J Infrared Milli Terahz Waves, 2015: p. 1-11.
http://dx.doi.org/10.1007/s10762-015-0176-2
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07-01-2015 02:40 PM
Dynamic nuclear polarization using frequency modulation at 3.34T
From The DNP-NMR Blog:
Dynamic nuclear polarization using frequency modulation at 3.34T
Hovav, Y., et al., Dynamic nuclear polarization using frequency modulation at 3.34T. J Magn Reson, 2013. 238C(0): p. 94-105.
http://www.ncbi.nlm.nih.gov/pubmed/24333831
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01-06-2014 08:50 PM
First tests of a 527 GHz gyrotron for dynamic nuclear polarization
From The DNP-NMR Blog:
First tests of a 527 GHz gyrotron for dynamic nuclear polarization
Felch, K., et al. First tests of a 527 GHz gyrotron for dynamic nuclear polarization. in Vacuum Electronics Conference (IVEC), 2013 IEEE 14th International. 2013.
http://dx.doi.org/10.1109/IVEC.2013.6571048
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09-02-2013 10:45 PM
High Frequency Dynamic Nuclear Polarization
From The DNP-NMR Blog:
High Frequency Dynamic Nuclear Polarization
Ni, Q.Z., et al., High Frequency Dynamic Nuclear Polarization. Acc Chem Res, 2013.
http://www.ncbi.nlm.nih.gov/pubmed/23597038
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06-07-2013 10:42 PM
A 250 GHz Gyrotron with a 3 GHz Tuning Bandwidth for Dynamic Nuclear Polarization
A 250 GHz Gyrotron with a 3 GHz Tuning Bandwidth for Dynamic Nuclear Polarization
Publication year: 2012
Source:Journal of Magnetic Resonance</br>
Alexander B. Barnes, Emilio A. Nanni, Judith Herzfeld, Robert G. Griffin, Richard J. Temkin</br>
We describe the design and implementation of a novel tunable 250 GHz gyrotron oscillator with >10 W output power over most of a 3 GHz band and >35 W peak power. The tuning bandwidth and power are sufficient to generate a >1 MHz nutation frequency across the entire nitroxide EPR lineshape for cross effect DNP, as well as to...