GB579319A - Improvements in or relating to electron discharge devices - Google Patents

Abstract

579,319. Discharge apparatus. LIEBMANN, G., and CATHODEON, Ltd. Feb. 23, 1942, No. 2342. [Class 39 (i)] In an ultra-high frequency tube the cathode and next nearest grid or anode are closely spaced by a hollow cylindrical spacer. The electrodes project into the spacer so that it surrounds the discharge space but lies outside it. Preferably, the spacing is less than 5 Î 10<-3> cm. and the current density in the discharge is greater than 0.1 amp./cm<2>. In a diode, the cathode 7, Fig. 1, and anode 9 project into the spacer 10 which engages shoulders 11, 12. The spacer 10 by itself brings the electrode surfaces into contact, but an auxiliary spacer 13 accurately ground to the desired electrode separation is interposed to give the required separation. The cathode is secured by band 8 to a ring 6 screwed into a nut 5 ; the anode and the nut 5 contact opposite faces 2, 3 of a resonator extending outside the envelope. In a modification, the electrodes are truncated cones and fit against conical faces on the spacer. Holes are made in the electrodes or spacers to facilitate exhaustion. In a triode, grid 29, Fig. 3, and cathode 25 are similarly supported within spacer 31, the cathode being pressed thereon by spring 39. The anode 24 is spaced from the grid by a spacer 34. Discs 21, 22, 23 connected to the electrodes pass out through the wall of the envelope to input and output resonators 45, 44. To prevent the lowering of the surface insulation of the spacers by deposited metal, the surface may be roughened, 'and narrow gaps 32, 33 are left between the electrodes and the ends of the spacer. The invention is also applicable to cathode-ray tubes.