Virtual cathode oscillator study

The main thrust of research in the second year of this program has been experimental. This report summarizes the progress made in developing the hardware for a millimeter wavelength virtual cathode microwave oscillator (Vircator). Fabrication, testing, and calibration of two critical components, the solenoidal magnet and the millimeter microwave spectrometer, is complete. Data summary and complete documentation of the testing of the magnetic field coil at the 30 kG level, is presented in Section 2. Calibration data for the spectrometer, covering the entire 35 to 100 GHz frequency range, is presented in Section 3. Section 4 describes the successful operation of the electron beam pulse power system, based on an artificial Blumlein design. A unique cathode material is described which allows fast turn of electron field emission, at field strengths of approximately 50 kV/cm and very slow anode-cathode gap closure rates, less than 1 cm/Microsecs.