Velocity-modulated electron multiplier.
An electron beam is first bunched, or velocity-modulated, and is then multiplied, in the same tube, by secondary emission. The high gain thus secured allows both the primary beam, and its transit time, to be kept comparatively small, and so gives the tube a high input impedance.
In the amplifier shown, electrons from the gun G pass through the centre gap in a resonator R, which is coupled to an input loop L. The bunched stream is next projected against a series of secondary-emission electrodes, as indicated by the arrows; the stream is multiplied or intensified at each impact, without losing its characteristic grouping, since the new electrons are liberated instantaneously. The augmented stream is then focused through the gap in a second resonator R1, where it delivers up energy to be drawn off through the output loop L1. The spent electrons are collected from the stream by an anode A.
Standard Telephones and Cables, Ltd. (assignees of R V L Hartley and C V Parker). Application date April 30th, 1942. N0. 578271.