GB618258A - High density electron beam tube - Google Patents

Abstract

618,258. Electron beam apparatus. STANDARD TELEPHONES & CABLES, Ltd. June 6, 1946, No. 17264. Convention date, June 23, 1945. [Class 39 (i)] In apparatus for obtaining improved gasfocusing of electron beams in long tubes at residual gas pressures of 10<-7> mms., as in Specification 579,371, the electrodes to which ion-confining voltage is applied are either within the tube 4, Figs. 1 and 6, or between the ends of the tube and the further apertured electrodes 2, Fig. 5. These further apertured electrodes may be at a potential the same as or different from that of the drift tube; in the first case they may merely be flanges integral with the ends of the tube, Fig. 6. The ionconfining electrodes may be short cylinders 5, Fig. 1, rings 11, Fig. 6, or grids; in the latter case they may be a combination of three grids 10, Fig. 5, the outer ones being connected together and to the drift tube. The ionconfining voltage may be obtained by means of a.dropping resistance carrying the electron current collected by the tube. The invention may be applied to the drift tubes of velocitymodulation devices. The Specification as open to inspection under Sect. 91 states that the invention is applicable also to beam power transmitting and receiving tubes, television projecting tubes and highintensity X-ray tubes. This subject-matter does not appear in the Specification as accepted.