GB754811A - Reflex klystron oscillator tube - Google Patents

Abstract

754,811. Velocity modulated tubes. SPERRY CORPORATION. Oct. 22, 1954 [Dec. 2, 1953], No. 30488/54. Class 39 (1). A reflex lilystron with a residual ion focused beam has between the cathode and resonator gap a conductive tube 26, Fig. 1, which carries one or more fins or vanes 50, preferably channelshaped, which project inwardly but which leave a central passage for the electron beam; the members 50 trap secondaries produced in tube 26 by reflected electrons, and this improves operation of the tube in frequency modulated circuits. As shown, the fins or vanes 50 of nickel are spot-welded to nickel sleeve 52, pressed into tube 26 and members 50, 52 are carbonized to reduce secondary emission due to impact of reflected electrons. It is stated that when used for frequency modulation, modulation of the reflector voltage causes modulation of the secondaries generated at 26 and consequently tends to excite plasma oscillations of the ions trapped in tube 26. This causes an enlargement of the beam diameter and a consequent undesired shift in carrier frequency, i.e. the basic resonator frequency, thus distorting the transmitted information. The vanes or fins 50 tend to trap secondaries produced in 26 and modify the potential drop between the tube walls and beam which is also normally conducive to the setting up of plasma oscillations. The ions trapped within tube 26 cause ion focusing of the beam. The vanes 50 do not extend the whole length of tube 26 which has resonator grid 28 and smoother grid 31 at its ends. The device is tuned by screws 40 reacting against springs 44 to deform flexible wall 16, the spring pressure being varied by studs 45 having adjusting nuts 47. The modulation frequency applied to the reflector is varied over a video frequency band.