Phenomena in Oxide-Coated Filament Electron Tubes

Abstract

Thermionic Phenomena in Wehnelt Oxide Electron Tubes.—The author discusses some of the problems which have arisen in connection with the development of three-electrode vacuum tubes with special reference to the production of a highly active and uniform thermionic source of electrons. The materials and the methods for the preparation of both core and coating are given. Since tubes with these filaments are not self-evacuating by the clean-up effect to the extent found with tungsten filaments, greater care is necessary in the pumping process.