Electron Paramagnetic Resonance Instrument with Superconductive Cavity.

The EPR instrument includes an X band klystron used to generate microwave power that is transmitted to a superconductive waveguide cavity resonator. The cavity is placed between the pole pieces of a large d-c magnet and small a-c magnetic coils energized by a modulation signal source. A microwave crystal detector detects RF energy outputted from the cavity. The detector output is amplified, rectified and filtered in a phase sensitive filter that uses the modulation signal source as a reference. The resultant signal is recorded by an amplitude vs. time recorder. The superconductive cavity includes an inner wall of high-temperature superconductive material, a liquid coolant and an insulating sleeve that passes through the cavity. The specimen to be analyzed is placed in the sleeve. Patents application. (JHD)