GB473571A - Improvements in or relating to secondary emission electron multipliers - Google Patents

Abstract

473,571. Electron multipliers. GENERAL ELECTRIC CO., Ltd., and ALDOUS, W. H. July 31, 1936, No. 21233. [Class 39 (i)] Modulation of the output current, in a multistage electron multiplier of the type in which electrons are guided in a non- straight path between the secondary electron emitting targets, is effected by dividing one target into two or more parts having different coefficients of emission and moving the incident electron stream from one part to another. In one form the targets are arranged linearly in one plane with opposed accelerating electrodes each connected to the succeeding target, and a magnetic field guides the electrons from one target to the next. One target is divided into two portions having different emissions, the dividing line being either parallel or perpendicular to the direction of electron travel, and the beam is deflected by varying the accelerating field, the magnetic field or a separate transverse electric field. In the zigzag type shown, the target B is divided into two parts B1, B2 of different emissions and the electron beam, focused by electrostatic or magnetic lenses, is deflected from one to the other by deflecting plates C. To avoid disturbance of the electron path by the modulation deflection, two targets may be divided into two parts B1, B2; B<1>1, B<1>2 (not shown), such that B1 is similarly situated to B<1>1 but has the same emission as B<1>2 and vice versa ; the beam is deflected simultaneously from B1 to B2 and from B<1>2 to B<1>1. A target may be divided into three parts, the outer parts being similar in emission ; if a sinusoidal deflection is applied to the beam, harmonics will be generated. Specification 427,509 is referred to.