GB478967A - Improvements in or relating to electric discharge devices - Google Patents

Abstract

478,967. Electron multipliers; cathoderay tubes. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. July 27, 1936, No. 20737. Convention date, July 26, 1935. [Class 39 (i)] A device comprises a mosaic electrode upon which is projected either an optical image or an electron image generated at a photo-electric surface and which is scanned by a cathoderay beam, and air electron multiplier arrangement which receives and amplifies the secondary electrons emitted by the mosaic. In one form, Fig. 2, the mosaic comprises a mica plate 11, photo-electric particles 13 and a back-plate 15. A focusing electrode 19 coated on the limb 3 of the tube containing the gun system 2, 5, 7 serves also to attract photo- and secondary-electrons from the mosaic. These electrons pass into a second limb 23 in which is mounted a multiplier of the kind described in Specification 469,488, having secondary-electron-emissive targets 29, 31, accelerating and focusing electrodes 25, 26, 33, 35, 37, 39 and an output electrode 27. The mode of manufacture of the multiplier is described and includes the step of caesiating the electrodes 31 and the mosaic 11 simultaneously. The limb 23 may be cylindrical. The output electrode 27 is connected to an amplifier 49. A plurality of parallel-connected multipliers may be arranged to receive the output from the mosaic. In a modification, Fig. 3, the multiplying electrodes are formed by the interior surfaces 29, 31 of T-tube electrodes 33, 39 the portions 33, 37 serving as focusing and accelerating electrodes. The mosaic may be two-sided, as described in Specification 454,422. Specification 442,666 also is referred to.