A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies
We described a versatile spectrometer designed for the study of dynamic nuclear polarization (DNP) at low temperatures and high fields. The instrument functions both as an NMR spectrometer operating at 212 MHz ([superscript 1]H frequency) with DNP capabilities, and as a pulsed-EPR operating at 140 G...
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| Language: | en_US |
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Elsevier
2015
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| Online Access: | http://hdl.handle.net/1721.1/99511 https://orcid.org/0000-0003-1589-832X https://orcid.org/0000-0002-1148-9345 https://orcid.org/0000-0001-9813-0177 |
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| author | Smith, Albert A. Bryant, Jeffrey A. DeRocher, Ronald Woskov, Paul P. Corzilius, Bjorn Griffin, Robert Guy Temkin, Richard J |
| author2 | Massachusetts Institute of Technology. Department of Chemistry |
| author_facet | Massachusetts Institute of Technology. Department of Chemistry Smith, Albert A. Bryant, Jeffrey A. DeRocher, Ronald Woskov, Paul P. Corzilius, Bjorn Griffin, Robert Guy Temkin, Richard J |
| author_sort | Smith, Albert A. |
| collection | MIT |
| description | We described a versatile spectrometer designed for the study of dynamic nuclear polarization (DNP) at low temperatures and high fields. The instrument functions both as an NMR spectrometer operating at 212 MHz ([superscript 1]H frequency) with DNP capabilities, and as a pulsed-EPR operating at 140 GHz. A coiled TE[subscript 011] resonator acts as both an NMR coil and microwave resonator, and a double balanced ([superscript 1]H, [superscript 13]C) radio frequency circuit greatly stabilizes the NMR performance. A new 140 GHz microwave bridge has also been developed, which utilizes a four-phase network and ELDOR channel at 8.75 GHz, that is then multiplied and mixed to obtain 140 GHz microwave pulses with an output power of 120 mW. Nutation frequencies obtained are as follows: 6 MHz on S = 1/2 electron spins, 100 kHz on [superscript 1]H, and 50 kHz on [superscript 13]C. We demonstrate basic EPR, ELDOR, ENDOR, and DNP experiments here. Our solid effect DNP results demonstrate an enhancement of 144 and sensitivity gain of 310 using OX063 trityl at 80 K and an enhancement of 157 and maximum sensitivity gain of 234 using Gd-DOTA at 20 K, which is significantly better performance than previously reported at high fields (⩾3 T). |
| first_indexed | 2024-09-23T13:35:11Z |
| format | Article |
| id | mit-1721.1/99511 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T13:35:11Z |
| publishDate | 2015 |
| publisher | Elsevier |
| record_format | dspace |
| spelling | mit-1721.1/995112022-09-28T14:49:12Z A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies Smith, Albert A. Bryant, Jeffrey A. DeRocher, Ronald Woskov, Paul P. Corzilius, Bjorn Griffin, Robert Guy Temkin, Richard J 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) Smith, Albert A. Corzilius, Bjorn Bryant, Jeffrey A. DeRocher, Ronald Woskov, Paul P. Temkin, Richard J. Griffin, Robert Guy We described a versatile spectrometer designed for the study of dynamic nuclear polarization (DNP) at low temperatures and high fields. The instrument functions both as an NMR spectrometer operating at 212 MHz ([superscript 1]H frequency) with DNP capabilities, and as a pulsed-EPR operating at 140 GHz. A coiled TE[subscript 011] resonator acts as both an NMR coil and microwave resonator, and a double balanced ([superscript 1]H, [superscript 13]C) radio frequency circuit greatly stabilizes the NMR performance. A new 140 GHz microwave bridge has also been developed, which utilizes a four-phase network and ELDOR channel at 8.75 GHz, that is then multiplied and mixed to obtain 140 GHz microwave pulses with an output power of 120 mW. Nutation frequencies obtained are as follows: 6 MHz on S = 1/2 electron spins, 100 kHz on [superscript 1]H, and 50 kHz on [superscript 13]C. We demonstrate basic EPR, ELDOR, ENDOR, and DNP experiments here. Our solid effect DNP results demonstrate an enhancement of 144 and sensitivity gain of 310 using OX063 trityl at 80 K and an enhancement of 157 and maximum sensitivity gain of 234 using Gd-DOTA at 20 K, which is significantly better performance than previously reported at high fields (⩾3 T). National Institutes of Health (U.S.) (EB002804) National Institutes of Health (U.S.) (EB002026) National Institutes of Health (U.S.) (EB001965) National Institutes of Health (U.S.) (EB004866) Deutsche Forschungsgemeinschaft (Postdoctoral Fellowship) 2015-10-29T17:39:35Z 2015-10-29T17:39:35Z 2012-07 2012-06 Article http://purl.org/eprint/type/JournalArticle 10907807 1096-0856 http://hdl.handle.net/1721.1/99511 Smith, Albert A., Björn Corzilius, Jeffrey A. Bryant, Ronald DeRocher, Paul P. Woskov, Richard J. Temkin, and Robert G. Griffin. “A 140GHz Pulsed EPR/212MHz NMR Spectrometer for DNP Studies.” Journal of Magnetic Resonance 223 (October 2012): 170–179. https://orcid.org/0000-0003-1589-832X https://orcid.org/0000-0002-1148-9345 https://orcid.org/0000-0001-9813-0177 en_US http://dx.doi.org/10.1016/j.jmr.2012.07.008 Journal of Magnetic Resonance Creative Commons Attribution-Noncommercial-NoDerivatives http://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf Elsevier PMC |
| spellingShingle | Smith, Albert A. Bryant, Jeffrey A. DeRocher, Ronald Woskov, Paul P. Corzilius, Bjorn Griffin, Robert Guy Temkin, Richard J A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies |
| title | A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies |
| title_full | A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies |
| title_fullStr | A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies |
| title_full_unstemmed | A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies |
| title_short | A 140 GHz pulsed EPR/212 MHz NMR spectrometer for DNP studies |
| title_sort | 140 ghz pulsed epr 212 mhz nmr spectrometer for dnp studies |
| url | http://hdl.handle.net/1721.1/99511 https://orcid.org/0000-0003-1589-832X https://orcid.org/0000-0002-1148-9345 https://orcid.org/0000-0001-9813-0177 |
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