Pulsed magnetron tube having improved electron emitter assembly

摘要

A tuning assembly (42) is disclosed for selectively oscillating the frequency of an electromagnetic field within a hermetically sealed pulsed magnetron (12), comprising a rigid, hermetically sealed housing (14), apparatus for generating the electromagnetic field therewithin (32, 34, and 36), and elements for defining a cavity (30) within the housing for establishing the frequency of the electromagnetic field. The tuning assembly (42) includes electrically conductive members (54) mounted for linear movement within the cavity (30) to oscillate the established frequency. Elements (52) disposed within the rigid housing (14) are provided for mounting the electrically conductive members (54), and are adapted for oscillatory movement at a predetermined mechanical resonant frequency to move the electrically conductive members (54) linearly. The tuning assembly (42) incorporates a highly efficient electron-emitter (cathode) assembly (24, 102) arranged in the form of a tightly-wound, helical member (102), the cathode assembly (24, 102) being directly heated and composed of porous tungsten impregnated by a mixture of barium and calcium aluminates. The helical member (102) is machined and has a rectangular cross-section, so as to present a substantially cylindrical emitting surface having a maximum emitting area. Finally, a power source (108) is provided exterior to the rigid housing (14) and is magnetically coupled to the mounting elements (44) for exciting them.