GB520973A - Improvements in or relating to electron multipliers - Google Patents

Abstract

520,973. Electron multipliers. MARCONI'S WIRELESS TELEGRAPH CO., Ltd., and GILL, E. W. B. Nov. 5, 1938, No. 32124. [Class 39 (i)] An electron multiplier comprising a cathode and one or more secondary-emitting electrodes has means for submitting the discharge space to a unidirectional magnetic field and a highfrequency electrostatic field, the fields and electrode arrangements being such that the electrons move in spiral paths to the next emitting or the output electrode while being constantly accelerated. In the form shown, the high frequency field is applied by a tuned circuit TC to plates PI, P2 mounted inside or outside the enclosing vessel and parallel to the plane in which is disposed the electrode system consisting of a filamentary cathode F, parallel secondary-emitting filamentary electrodes S1, S2 ... S6 and an output plate electrode C. The cathode is heated by a source FB and is connected to the midpoint MP of the tuned circuit and to the plate C, optionally through a battery CB which may be used to keep the plate positive with respect to the cathode. The direction of the magnetic field is perpendicular to the plane of the paper, i.e. substantially parallel to the emitters S1 ... S6. The distance between the cathode and first emitter may be less than half that between the plates PI, P2 and the distances between the emitters S1 ... S6 may be progressively smaller in the direction towards the output electrode.