EFFECTS OF ELECTRON BEAM CONFINEMENT ON KLYSTRON EFFICIENCY

The effects of magnetic field configuration on klystron efficiency were measured, especially the effects of introducing magnetic flux at the cathode, leading to so-called confined flow in the electron beam. The experiments were performed using a two-cavity klystron of special design, incorporating a movable tput cavity and a scanning iris. The scanning iris permitted measurements of dc and rf current distribution in the beam; longitudinal movement of the cavity made these measurements possible at various axial positions and allowed the determination of optimum cavity spacing. Detailed studies were made on four beams requiring magnetic focusing fields of up to twice the Brillouin field. Detailed current distributions in these beams were used in determining various parameters useful in analyzing klystron performance, such as plasma wavelength, beam coupling coefficients, and beam loading conductance. (Author)