Probehead operating at 35 GHz for continuous wave and pulse electron paramagnetic resonance applications

The design, construction, numerical modeling, and performance of a probehead for electron paramagnetic resonance (EPR) spectroscopy at 34-36 GHz is described. A classical cylindrical cavity operating in the TE011 mode with adjustable frequency and coupling has been found to be well suited for continuous wave and pulse EPR studies of frozen solutions of transition metal complexes at low temperature. The highest attention is given to the probehead performance in the pulse mode. The implemented design has been analyzed in detail using numerical modeling. The distribution of the electromagnetic fields, eigenfrequencies, quality factors, coupling coefficients, and conversion factors are calculated and compared with experimental data. The results demonstrate the effectiveness of the design and can serve as a guide for probehead optimization. (c) 2006 American Institute of Physics.