Electron beam tube for analog-to-digital conversion

A beam deflection tube is described which converts the amplitude of an input voltage into an eight digit binary output at sampling rates up to ten megacycles per second. The tube employs a ribbon beam with a line focus, which impinges on eight columns of apertures in a code plate. The line focus is oriented perpendicular to the columns of apertures and the beam is electrostatically deflected by the input signal in a direction parallel to them. These apertures are arranged so that the electrons penetrate the "digit columns" in a binary pattern which identifies the beam position. Output collector electrodes, one associated With each digit column, produce output currents in parallel, An output current of 50 microamperes per digit is obtained by the use of a single stage of secondary electron multiplication before final electron collection. The important tube design parameters are discussed with emphasis on deflection plate design for maximum performance with minimum aberrations.