Patent ID: 8957394
Filing Date: 2015-02-17
Classification: G21K,H01J

Abstract:
1. A high-voltage electron gun comprising: an insulator stand-off having first and second open ends; a resistive layer on the insulator stand-off, wherein the resistive layer is at least on an interior surface of the insulator stand-off; a cathode holder coupled to the first open end of the insulator stand-off, wherein the cathode holder holds a cathode emitter from which electrons are emitted; an anode coupled to the second open end of the insulator stand-off and having an opening through which an electron beam formed from the emitted electrons is output; a first control electrode which is positioned within the insulator stand-off between the cathode holder and the anode; a first electrical connection through the insulator stand-off to the first control electrode; a second control electrode which is positioned within the insulator stand-off between the first control electrode and the anode, wherein the first control electrode is smaller than the second control electrode such that the first control electrode is farther away from the electron beam than the second control electrode, and an inner diameter of the second control electrode is smaller than an inner diameter of the first control electrode; and a second electrical connection through the insulator stand-off to the second control electrode; a third control electrode which is positioned within the insulator stand-off between the second control electrode and the anode, wherein the second control electrode is smaller than the third control electrode such that the second control electrode is farther away from the electron beam than the third control electrode, and an inner diameter of the third control electrode is smaller than the inner diameter of the second control electrode; and a third electrical connection through the insulator stand-off to the third control electrode.