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Advantages of High Frequency EPR

  • Increase in spectral resolution due to the higher magnetic field.
  • Increase in detection sensitivity for samples of limited quantity due to higher resonator filling factor.
  • Increase in orientation selectivity in the investigation of disordered systems.
  • Accessibility of spin systems with larger zero-field splitting due to the larger microwave quantum energy.
  • Better separation of the ENDOR spectra of different nuclei.
  • Improvement in the ENDOR detectability of low-frequency nuclear spins.
  • Simplification of spectra due to the reduction of second-order effects at high fields.
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MW-Nutation of Coal Sample at 94 GHz. The nutation period is 62 ns with the 400 mW High Power Upgrade unit.

EPR 6T SC: The W-Band Superconducting Magnet

The second generation of W-band superconducting magnet features a horizontal field, a main coil with 6 T sweep range, permanent leads and a 2 kG high resolution sweep coil. The state-of-the-art magnet design features permanent leads for the main coil and sweep coil with a longer helium hold time compared to similar designs. Both, main and sweep-coil are connected to the newly developed power supply. Easy and safe operation is accomplished by a new software interface which allows switching between the two operation modes just by a mouse click.

EPR 6T SC: The W-Band Superconducting Magnet
EPR 6T SC: The W-Band Superconducting Magnet

W-Band Bridge High Power Upgrades

For pulse EPR measurements where short pulses and large excitation bandwidths are desired (ESEEM, DEER, and FT), two W-band bridge upgrades are available: the 400 mW and 100 mW High Power Upgrade.  The 400 mW High Power Upgrade with the standard W-band resonator achieves pulse lengths (90o) of 16 ns.  While the 100 mW High Power Upgrade routinely achieves pulse lengths (90o) of 40 ns.
The benefits of the 400 mW High Power Upgrade are easily observed in the 4-pulse DEER Experiment.  The shorter pulse lengths lead to a higher signal to noise in the DEER spectrum which translates to a decrease in measuring time when compared to the longer pulses needed with the 100 mW High Power Upgrade.

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4-Pulse DEER time traces: 400 mW High Power Upgrade (red, upper) and 100 mW High Power Upgrade (green, lower)