Er 041 mr microwave bridge

X-band continuous wave (CW) measurements were performed on a Bruker ESP 300 spectrometer with an ER 041 MR microwave bridge and an ER 4116DM resonator. All other EPR measurements were performed on a Bruker Elexsys E580 X-band spectrometer equipped with a SuperX-FT microwave bridge. For pulse EPR measurements at X-band, a Bruker ER 4118X-MS5 resonator was used in concert with an Oxford CF935 helium flow cryostat. Microwave pulses generated by the microwave bridge were amplified by a 1 kW traveling wave tube (TWT) amplifier (Applied Systems Engineering, model 117x). Pulse EPR spectra at Q-band frequencies were acquired using a home-built intermediate-frequency extension of the SuperX-FT X-band bridge that has a Millitech 5W pulse power amplifier. All experiments were conducted on a home-built TE₀₁₁ resonator utilizing the open resonator concept developed by Annino et al.⁶² and mechanical construction of the probehead similar to that presented by Reijerse et al.^{63 (link)} This setup allows t(π/2) = 12–16 ns at maximum input power with spectrometer dead time (including the resonator ring time) of 100–120 ns. Data acquisition and control of experimental parameters were performed by using Bruker XEPR software.

X-band CW measurements were performed on a Bruker ESP 300 spectrometer with an ER 041 MR microwave bridge and an ER 4116DM resonator. All other EPR measurements were performed on a Bruker Elexsys E580 X-band spectrometer equipped with a SuperX-FT microwave bridge. For pulse EPR measurements at X-band, a Bruker EN 4118X-MD4 dielectric ENDOR resonator was used in concert with an Oxford CF935 helium flow cryostat. Pulse EPR spectra at Q-band frequencies were acquired using a home-built intermediate-frequency extension of the SuperX-FT X-band bridge equipped with a Millitech 5W pulse power amplifier.