Patent ID: 8593048
Filing Date: 2013-11-26
Classification: H01J

Abstract:
1. An electron source having a cathode of tungsten single crystal and a diffusion source formed on the central region of the cathode, wherein the angle between the axial direction of the cathode and the <100> direction of the cathode is adjusted so that the electrons emitted from the boundary region between the (100) and (110) planes formed on the cathode tip is directed almost in parallel with the axis of the cathode, wherein the angle between the axial direction of the cathode and the <100> direction of the cathode is 22.5±10°, and the crystal orientation in the axial direction of the cathode is in the <310> direction, and the boundary region between the (100) and (110) planes is formed on the cathode tip at an angle that causes electrons to be emitted at a higher angular current density in the boundary region.