Fig. 1. Structure diagram of the miniature X-ray source

Fig. 2. Schematic diagram of the electron beam focusing structure. (a) Overall structure; (b) half section

Fig. 3. Simulation result of electric optics. (a) Voltage contour in the YZ plane; (b) electron beam trajectories in the YZ plane; (c) voltage contour in the XZ plane; (d) electron beam trajectories in the XZ plane; (e) two-dimensional coordinate of focusing spot

Fig. 4. Simulation result of focal spot size versus cathode voltage

Fig. 5. Photographs of the prototype. (a) Photograph of miniature sealed X-ray tube; (b) photograph of integrated miniature X-ray source

Fig. 6. X-ray spectrum of tungsten target

Fig. 7. Stability measurement result of the X-ray flux

Fig. 8. High voltage stability measurement result. (a) Bremsstrahlung edge spectrum and fitting result; (b) high voltage changes over time

Fig. 9. Spot size measurement result. (a) Pinhole camera image of the X-ray spot at 50 kV; (b) spot size versus cathode voltage