Microwave cavity resonators for a paramagnetic-resonance spectrometer
Wetsel, Grover Cleveland
Donoho, Paul L.
Master of Arts
The purpose of this investigation is to study, design, and build microwave cavity resonators for use at both room and low temperatures with an electron para-magnetic resonance (EPR) spectrometer. The resonant cavity provides the high frequency magnetic field necessary for resonance absorption in paramagnetic solids; and it must be carefully constructed such that it will have a high Q and low noise, A high Q is necessary because the spectrometer detector signal is directly proportional to Q and the minimum detectable signal is inversely proportional to Q. In order to reduce the noise due to interactions between the DC magnetic field and currents induced in the walls by the modulation field, the cavity must be constructed of a non-conducting material coated with a thin layer of silver. The problems connected with the design and construction of such a cavity are discussed in detail, and characteristics are given for the resulting resonators.