GB501740A - Method of and means for controlling the operation of electron multiplying tubes - Google Patents

Abstract

501,740. Electron multipliers and circuits therefor. VEREINIGTE GLUHLAMPEN UND ELEKTRIZITATS AKT.- GES. Aug. 30, 1937, No. 23673. Convention date, Aug. 28,1936. Drawings to Specification. [Classes 39 (i) and 40 (v)] The electron beam leaving a cathode of an electron multiplier is passed through one or more screens with rectangular or slot-like openings so'as to restrict the beam to electrons having approximately the same velocity and direction and is then subjected to velocity and deflection control so as to cause the beam to fall either on a multiplying or a non-multiplying electrode as required ; if the path of the beam is guided in known manner by a magnetic field and accelerating electrodes the initial velocity of the beam should,be at right angles to the magnetic field and parallel to the field of the accelerating electrodes. Deflection plates for controlling the beam should be parallel to both the electric and magnetic fields. Velocity control may be produced by a grid. The non- emissive electrode may be coated with carbon and may form part of the same plate as the emissive electrode; any secondary emission from the non-emissive electrode may also be suppressed by a grid. The beam can be controlled at different stages; e.g. a weak signal may act on the discharge behind the primary cathode and a stronger local signal behind a multiplying electrode; the local signal may also be back-coupled on to the control member by means of an auxiliary anode near the working anode.