Dispenser cathode for a grid-controlled electron tube and method of manufacturing same

Abstract From the Canadian patent

A sintered dispenser cathode for a gridcontrolled electron tube in which for using the grid current the emission of the surface regions immediately opposite to the control grid is reduced the surface, regions of reduced emissions being constructed as projections of the cathode body having a focusing effect. The projections may be formed already during the sintering of the cathode body in that the remaining active surface regions of the emissive surface of the cathode are deopenod by a material-removing process or in that parts of the surface are fused. In so far the projections have not been passivated during the manufacture thereof they are, passivated at their surface by a suitable method …