High-Bandwidth Q-Band EPR Resonators
- Авторы: Tschaggelar R.1, Breitgoff F.1, Oberhänsli O.1, Qi M.2, Godt A.2, Jeschke G.1
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Учреждения:
- Laboratory of Physical Chemistry, ETH Zurich
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University
- Выпуск: Том 48, № 11-12 (2017)
- Страницы: 1273-1300
- Раздел: Original Paper
- URL: https://journals.rcsi.science/0937-9347/article/view/247994
- DOI: https://doi.org/10.1007/s00723-017-0956-z
- ID: 247994
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Аннотация
The emerging technology of ultra-wide-band spectrometers in electron paramagnetic resonance—enabled by recent technological advances—provides the means for new experimental schemes, a broader range of samples, and huge gains in measurement time. Broadband detection does, however, require that the resonator provides sufficient bandwidth and, despite resonator compensation schemes, excitation bandwidth is ultimately limited by resonator bandwidth. Here, we present the design of three resonators for Q-band frequencies (33–36 GHz) with a larger bandwidth than what was reported so far. The new resonators are of a loop-gap type with 4–6 loops and were designed for 1.6 mm sample tubes to achieve higher field homogeneity than in existing resonators for 3 mm samples, a feature that is beneficial for precise spin control. The loop-gap design provides good separation of the B1 and E field, enabling robust modes with powder samples as well as with frozen water samples as the resonant behavior is largely independent of the dielectric properties of the samples. Experiments confirm the trends in bandwidth and field strength and the increased B1 field homogeneity predicted by the simulations. Variation of the position of the coupling rod allows the adjustment of the quality factor Q and thus the bandwidth over a broad range. The increased bandwidth of the loop-gap resonators was exploited in double electron–electron resonance measurements of a Cu(II)-PyMTA ruler to yield significantly higher modulation depth and thus higher sensitivity.
Об авторах
Rene Tschaggelar
Laboratory of Physical Chemistry, ETH Zurich
Email: gunnar.jeschke@phys.chem.ethz.ch
Швейцария, Vladimir-Prelog-Weg 2, Zurich, 8093
Frauke Breitgoff
Laboratory of Physical Chemistry, ETH Zurich
Email: gunnar.jeschke@phys.chem.ethz.ch
Швейцария, Vladimir-Prelog-Weg 2, Zurich, 8093
Oliver Oberhänsli
Laboratory of Physical Chemistry, ETH Zurich
Email: gunnar.jeschke@phys.chem.ethz.ch
Швейцария, Vladimir-Prelog-Weg 2, Zurich, 8093
Mian Qi
Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University
Email: gunnar.jeschke@phys.chem.ethz.ch
Германия, Universitätsstraße 25, Bielefeld, 33615
Adelheid Godt
Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University
Email: gunnar.jeschke@phys.chem.ethz.ch
Германия, Universitätsstraße 25, Bielefeld, 33615
Gunnar Jeschke
Laboratory of Physical Chemistry, ETH Zurich
Автор, ответственный за переписку.
Email: gunnar.jeschke@phys.chem.ethz.ch
ORCID iD: 0000-0001-6853-8585
Швейцария, Vladimir-Prelog-Weg 2, Zurich, 8093