EPR Spectrometer: High Field (W-band, 95 GHz)
- 95 GHz/0-9.4 T
- 1 kW pulsed power
- Two adjustable/sweepable frequencies
The W-band pulsed EPR spectrometer, introduced in 2011, is one of only two of its design worldwide. It uses a Quasi-optical bridge and an induction-mode probe to provide the highest possible pulsed performance with deadtimes of less than 30 ns (potentially much less, depending on sample tuning). With a 1-kW peak pulsed power and 1-GHz bandwidth EIK amplifier, it is capable of
/2 pulses less than 8 ns. Both non-resonant waveguide and Fabry-Pérot sample holders are used. The 89-mm bore Varian magnet has permanent leads and a persistent mode switch, allowing the main field to either be swept or parked at an arbitrary field in the range of 0-9.4 T. The magnet is equipped with an internal sweep coil with a range of +/-700 G. The magnet is outfitted with an Oxford continuous flow cryostat, allowing for cryogenic experiments. Both the primary microwave frequency and a second channel for double resonance experiments can be varied over several GHz. Quadrature data is acquired with an Acqris digitizer with 500 ps resolution and on-card averaging. In continuous wave (CW) mode, the transmitter can supply up to 200 mW of microwave power. Both field and frequency modulation are available with the data collected by two, dual-channel, dual-harmonic lockin amplifiers for a total of eight channels of data simultaneously collected: quadrature with respect to microwave phase, quadrature with respect to modulation phase, and the preceding at the second harmonic of the modulation frequency.
Highlighted Research Applications
- Free radicals and metal complexes in materials and biological samples, including distance between these moieties
- Orientation of proteins and small molecules with surfaces.
- Structural biology
- Very fast acquisition of DEER spectra.
- Capable of Fourier transform (FT) spectroscopy
- Short deadtime assists in collection of ESEEM spectra.
All Related Publications Related Publications
- The Role of a Dipeptide Outer-Coordination Sphere on H2 -Production Catalysts: Influence on Catalytic Rates and Electron Transfer.
- Structural characterization of the model amphipathic peptide Ac-LKKLLKLLKKLLKL-NH2 in aqueous solution and with 2,2,2-trifluoroethanol and 1,1,1,3,3,3-hexafluoroisopropanol.
- Structure and Chemistry in Halide Lead-Tellurite Glasses.
- Metal-Centered 17-Electron Radicals CpM(CO)3• (M = Cr, Mo, W): A Combined Negative Ion Photoelectron Spectroscopic and Theoretical Study.
- Optimization of pulsed-DEER measurements for Gd-based labels: choice of operational frequencies, pulse durations and positions, and temperature.
Related Research Highlights
- Cryogenic NMR, theory help prove validity of photosynthesis model (Molecules Frozen Stiff)