A contribution on the triode system pf the cathode ray tube electron gun

By analysis of published experimental data it is shown that the triode system of the conventional electron gun is very inefficient from an electron-optical viewpoint. It is deduced that the deficiency arises from spherical aberration arising from the strong curvature of field immediately in front of the cathode, essentially still in ¿object space.¿ It is shown that the elimination of this defect would allow very appreciable reduction in the final beam angle, but that only partial advantage could be taken of this because of beam spreading due to space charge. A large reduction in cathode loading is then theoretically possible.