GB1325309A - Electron multiplying electrodes - Google Patents

Abstract

1325309 Electron multipliers EMI Ltd 28 Oct 1970 [13 Nov 1969] 55547/69 Heading H1D An electron multiplier comprises a stack of apertured metallic dynodes, such as 1 and 2, Fig. 1, each dynode carrying and being mutually spaced from an adjacent dynode by a corresponding apertured coating (3 and 4) to form a plurality of channels through the stack. The coatings may be of resistive material, so that the accelerating voltage can be applied across the stack, or of insulating material in which case individual connections must be made to each dynode. Alternatively each coating may be mainly insulating but include a resistive part, e.g. an annular portion. As shown, the apertures 5 are preferably tapered, and the coatings may be applied by evaporation on to the side with the narrower openings. In Fig. 1 the apertures are aligned to form linear channels, but they may be staggered to form zig-zag channels. The dynodes may be of beryllium-copper or of magnesium silver, and suitable insulating coatings are glass, silicon monoxide and alumina. The multiplier may be used to amplify a shaped electron pattern which is displayed on a fluorescent screen (Fig. 2, not shown).