ISSN:
1089-7623
Source:
AIP Digital Archive
Topics:
Physics
,
Electrical Engineering, Measurement and Control Technology
Notes:
The design principles for a broadband (up to 10 GHz) electron-paramagnetic-resonance (EPR) spectrometer are presented. The upper frequency limit is determined by the losses in the coaxial cables. The sample is inserted along the central conductor at the end of a short-circuited coaxial line that has an air dielectric. An adequate H1 field is generated near the surface of the central conductor and is proportional to the rf current therein. The short circuit of the cable serves to separate the E and H microwave fields with the sample predominately in the H-field portion. The instrument is currently operated in the cw mode in absorption with direct detection. The changes in the standing wave due to the resonance absorption are monitored through an E-field probe set at the first E node away from the truncation. A similar geometry is expected to be usable for broadband Fourier transform (FT) EPR spectrometry through the addition of appropriate pulse-generation equipment and signal-capture hardware. Also, obtaining frequency-swept spectra with or without frequency modulation is possible.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.1140388
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