GB527870A - Improvements in or relating to electron multipliers - Google Patents

Abstract

527,870. Electron multipliers. MARCONI'S WIRELESS TELEGRAPH CO. Ltd. April 21, 1939, No. 12110. Convention date, April 30, 1938. [Class 39 (i)] In an electron multiplier having a cathode, anode and a number of multiplier electrodes mounted in alternation on each side of a plane of symmetry, the output assembly consists of a convex electroncollecting surface presented to a concave secondaryemitting surface across an intervening space. Fig. 1 shows the application to a " duplex " multiplier comprising a thermionic cathode 1, control and accelerating grids common to two multiplying trains A, B, of secondary emitters 12, 14, 16, 18 and a pair of plates 4, 5 which define oppositely-directed streams of electrons from the cathode to the trains A and B. The last multiplying electrodes 18 are concave, and preferably of semi-cylindrical form with outwardlybent sections s which enclose the convex anodes 19, 20. The anode surfaces are preferably substantially cylindrical and defined by generatrices parallel to those defining the inner surfaces of the electrodes 18. Another form employs a photo-sensitive cathode at the beginning of a single linear series of two rows of opposed multiplying electrodes, the last of which is concave and presented on its inner surface to a convex anode, similarly to Fig. 1. The invention is applicable to both electrostatic and magnetic types of multiplier. Specification 520,117 is referred to.