Abstract:
A grid-controlled electron tube is constructed with a common anode and an array of individual cathode-grid modules. The simple modules can be built with greater accuracy than large, complex electrodes. The modules can be individually tested before final assembly, and can be individually replaced in case of a failure during construction or later operation. In a preferred embodiment, the cathode is a cylindrical filament surrounded by a coaxial grid, each grid turn being mounted to a common support on the side opposite the anode. In a tetrode embodiment, additional focusing bars at the sides of the grid direct electrons into beams which pass between large screen-grid wires.