Design and construction of a 95 GHz, 4th harmonic oscillator experiment

Summary form only given. Litton has been investigating a 4th harmonic, 4-cavity amplifier based on an axis-encircling electron beam from a new type of electron gun, the advanced center post gun. The current amplifier design utilizes a coaxial magnetron type output cavity. In this cavity, vanes extend nearly down to the electron beam´s outside diameter. The RF power is coupled through slots at the end of the gaps between the vanes into a coaxial cavity whose inner conductor is the outer conductor of the magnetron cavity. The majority of the RF stored energy in the system is in the coaxial cavity, so that the resonant frequency of the system may be adjusted by varying the resonance of the larger coaxial cavity. The output power is coupled into a waveguide through a hole in the outside diameter of the coaxial cavity. As a first RF test, an oscillator based on this type of cavity is being designed. A small signal code has been developed to study the oscillation threshold sensitivity to cavity dimensions and electron beam parameters.