High beam-current density of a 10-keV nano-focus X-ray source

摘要

The electron beam-current density at a target greatly affects imaging intensity and contrast when using a low-energy nano-focus X-ray source. This paper proposes a new electron gun comprising a 10-keV nano-focus X-ray source with a single-pole magnetic lens to improve its effective brightness and beam-current density. After analyzing the effect of the electric field on the extended Schottky emission, we first optimized the anode with high effective brightness and a fine virtual spot with enough intensity for nano-focus X-ray imaging. High effective beam-current density was then obtained by optimizing the position, geometry and electrical supplies of the single-pole magnetic lens. The effective brightness of this electron gun is 1.70x10(8) A.cm(-2).sr(-1), and the nano-focus X-ray source has a spot size of 41 nm when its tube current is 2 mu A. This electron gun achieves higher beam current density (1.6x10(5)A.cm(-2)), and its collimated landing beam efficiently transports the beam current in the X-ray source.