A novel gate structure for a miniature X-ray tube based on CNT emitters

We suggest a novel gate structure, Focusing-Functional Gate (FFG), having a focusing effect on the electron beams from the carbon nanotube (CNT) emitters for the miniature X-ray tubes. The FFG induced field emission from the CNT emitters and focused electron beams into the anode target without an additional focusing electrode, resulting in a small focal spot with little charging at the insulating body of the X-ray tube. We have successfully obtained a stable emission current and images from the miniature X-ray tube with the FFG.