GB486020A - Electron multiplier tubes and systems - Google Patents

Abstract

486,020. Electron multipliers and circuits therefor. STANDARD TELEPHONES & CABLES, Ltd. Nov. 27, 1936, No. 32556. Convention date, Dec. 28, 1395. [Classes 39 (i) and 40 (v)] An arrangement in which relatively out-of-phase potentials are applied to the electrodes from one or more oscillation sources is provided for continuously varying the strength, or direction, or both of the fields between secondary-emitting electrodes so that electrons emitted by each electrode are displaced towards the next electrode. Sinusoidal, pulsating rectified, or rectangular or saw-toothed voltages with phase displacements may be applied to successive multiplying electrodes or successive intermediate grids, so that the electrodes become positive in turn and attract all the electrons emitted from the preceding stages. The multiplier may comprise a caesiated mica cathode Ph, Fig. 8, an output electrode A, and multiplying grids 1, 2, 3, 4, 1<1>, 2<1>, 3<1>, 4<1>, connected in sequence to leads 6. Glass rods 5 support the structure. In a modification the multiplying electrodes are flat or curved plates arranged in helical fashion, and a magnet may be arranged axially. Each plate may be impacted twice. In the form shown in Fig. 11B, the main electrodes C, 1, 2, A are at fixed potentials and varying potentials are applied to the biassed grids g<1>, g<1>1, g<2> g<1>2, g<3>, g<1>3 ; screen or suppression grids may be provided. The multiplying electrodes may be successive frusta of a cone and may be water-cooled. The amplification may be varied by altering the number of stages, or by varying the biasses on the multiplying electrodes or on the field-producing grids. Two tubes may be connected in series by connecting the output electrode of one tube to the grid of the next. The varying potentials may be supplied from a common oscillator through phase-shift networks, or the oscillator may be replaced by an output filter selecting the output carrier frequency so that the tube is self-excited. The filtered output is then stabilized or modified as desired, e.g. to stabilize the non-carrier output. Positive or negative feed-back may be used in an amplifier circuit. The device may be used as an oscillator or modulator.