Beam and image experiment of beam deflection electron gun for distributed X-ray sources

摘要

Distributed X-ray sources comprise a single vacuum chamber containing multiple X-ray sources that are triggered and emit X-rays at a specific time and location.This process facilitates an application for innovative system concepts in X-ray and computer tomography.This paper proposes a novel electron beam focusing,shaping,and deflection electron gun for distributed X-ray sources.The electron gun uses a dispenser cathode as an electron emitter,a mesh grid to control emission current,and two electrostatic lenses for beam shaping,focusing,and deflection.Novel focusing and deflecting electrodes were designed to increase the number of focal spots in the distributed source.Two identical half-rectangle opening electrodes are controlled by adjusting the potential of the two electrodes to control the electron beam trajectory,and then,multifocal spots are obtained on the anode target.The electron gun can increase the spatial density of the distributed X-ray sources,thereby improving the image quality.The beam experimental results show that the focal spot sizes of the deflected (deflected amplitude 10.5 mm)and non-deflected electron beams at full width at half maximum are 0.80 mm × 0.50 mm and 0.55 mm × 0.40 mm,respectively (anode voltage 160 kV;beam current 30 mA).The imaging experimental results demonstrate the excellent spatial resolution and time resolution of an imaging system built with the sources,which has an excellent imaging effect on a field-programmable gate array chip and a rotating metal disk.