GB496705A - Improvements in or relating to electric discharge tubes utilising secondary emission - Google Patents

Abstract

496,705. Electron beam valves and multipliers. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. Aug. 30, 1937, No. 23721. Convention date, Sept. 1, 1936. [Class 39 (i)] In a discharge tube, one or more separate primary electron beams impinge partly on an anode 4 and partly on a secondary-emission electrode 5, the arrangement being such that when the anode potential increases the beams widen and the number of electrons diverted to the anode is increased, while the number of primary electrons passing to the secondaryemission electrode and consequently the number of secondary electrons collected by the anode is decreased ; an undesirable decrease in internal resistance is thereby avoided. In one form electrons from cathode 1, Fig. 1, are formed into four beams by rod control electrodes 2 and pass between screening electrodes 3 to anode 4 and secondary electrode 5 which completely surrounds the other electrodes. In another form, the secondary emission layer 6 does not completely cover the area of electrode 5 struck by the beam, so that on widening the beam the reduction in secondary emission is enhanced. The edge of the layer 6 may be shaped or serrated, Figs. 3, 4 (not shown), to adjust the characteristic to desired shape. The Specification as open to inspection under Sect. 91 includes also arrangements in which the anode is not struck by any part of the primary beam. This subject-matter does not appear in the Specification as accepted.