Designof New Electron Gun Capable of Generating Uniform Electron-Beam with Large Width

A novel type of electron gun,capable of generating uniform e-beam with a large beam width and a narrow energy spread,was developed for the purposes of degassing by e-beam scrubbing and evaluation of large-sized microchannel plate(MCP) with e-beam.The original work was the tantalum filament in a shape of flat-spiral coil because of its lower work function.The characteristics of the prototyped e-gun were experimentally tested and evaluated.The results show that the e-beam had a uniformity of higher than 90%,a stability of better than ±0.1 μA within a period of 12 h,and a dynamic range up to 7-order of magnitude(10^-12~10^-5 A).In addition,the e-beam,generated by the novel electron gun,was used to rigorously characterize the properties of an MCP,50 mm in diameter and degassed by e-beam scrubbing.