An electron gun. The electron gun includes an RE cavity having a first side with an emitting surface and a second side with a transmitting and emitting section. The gun also includes a mechanism for producing an oscillating force which encompasses the emitting surface and the section so electrons are directed between the emitting surface and the section to contact the emitting surface and generate additional electrons and to contact the section to generate additional electrons or escape the cavity through the section. A method for producing electrons.