Beam simulation and experiment of multi-focal spot electron gun for distributed X-ray sources

Distributed X-ray sources provide a solid foundation for the invention of new-generation computed tomography (CT). This study proposes a novel multi-focal spot electron gun scheme for distributed X-ray sources. The source in this study uses a dispenser cathode as the electron emitter, a mesh grid to control emission current, and two electrostatic lenses for beam shaping, focusing, and deflecting. Novel focusing and deflecting electrodes were designed to increase the number of focal spots in the distributed source. It consists of two identical half-rectangle opening electrodes by adjusting the potential of the two electrodes to control the trajectory of the electron beam and then obtain multi-focal spots on the anode target. The number of X-ray sources in the distributed source is limited by the amount of cathodes. The multi-focal spot electron gun can break this limitation and provide more possibilities and options for distributed X-ray sources and stationary CT. Experimental results reflect the excellent repeatability of the multi-spot electron gun. The dynamic effective focal spot sizes of the deflected (deflected amplitude, 10.5mm) and non-deflected electron beams at full with half max (FWHM) are 1.30mm × 0.60mm and 1.15mm × 0.55mm, respectively (anode voltage, 160kV; beam current, 30 mA).