GB490229A - Improvements in or relating to electron discharge devices - Google Patents

Abstract

490,229. Electron multipliers. FERNSEH AKT.-GES. Feb. 10, 1937, No. 4030. Convention date, Feb. 10, 1936. [Class 39 (i)] A multiplier comprises a plurality of secondary emitting electrodes in the form of portions of cones or of concentric annular rings, and the electrodes are of such size that the current density increases from stage to stage more slowly than does the amplification. In one form, Fig. 1, the stream from a cathode 16 is modulated by a grid 17 and falls upon a first target 18. The succeeding targets 19, 20, 21, 22, 23 are portions of coaxial cones. An annular collector 24 is provided. The generating lines of the cones may be logarithmic curves. Auxiliary electrodes 7, 8, 9, 10 and 11 may be provided, as described in Specification 490,230. The apical angle of the cone may be 180‹. In a modification, Fig. 4, an annular envelope 28 contains a cathode 32, flat annular targets 29, 30, 31 and accelerating electrodes 33, 34, 35 and is surrounded by a metal cylinder 25 having current leads 26, 38 such that an annular magnetic field is created. The widths of the targets 29, 30, 31 may increase successively. In another modification, the envelope is semicircular and the targets are semi-annular, the envelope lying in the field of a horseshoe magnet the lines of force of which follow approximately the targets.