GB485672A - Improvements in or relating to electron multiplier discharge devices and arrangements incorporating the same - Google Patents

Abstract

485,672. Electron multipliers; circuits. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Nov. 30, 1936, No. 32836. Convention date, Nov. 30,1935. [Classes 39 (i) and 40 (v)] An electron multiplier arrangement includes a source of electrons 13, a secondarily emissive electrode 23 situated in a plane substantially normal to the length of the source, magnetic means for deflecting the electrons from the source into curved paths and means including the electrode 23 for imparting to the electrons a component of velocity parallel to the length of the source 13, so that they describe helical paths about axes substantially parallel to the length of the source and impinge on the electrode 23 at an acute angle. An increased yield of secondary emission is obtained which is collected by an anode system 5 surrounding the source coaxially, the magnetic field being made so strong that the primary emission does not reach the anode. The anode system may be split or single. A further secondarily emissive electrode 21 may be positioned at the other end of the source. The source may be thermionic or photo-electric ; in the second case the anode is of mesh to allow light to fall on the source, the tube being backed by a reflector. If a tuned circuit be connected between plates 21, 23 the tube will generate oscillations. When used as an amplifier, the input is applied to a tuned circuit L, C, connected across the split anode system 55b and amplified oscillations are developed across L2 C2 connected between the secondarily emissive electrodes 61b, 63b. The fields are adjusted so that the electron orbits resonate with the amplified frequency. The Specification as open to inspection under Sect. 91 includes also inclining the axis of the magnetic field relatively to the length of the source. This subject-matter does not appear in the Specification as accepted.