High-Performance Cold Cathode X-ray Tubes Using a Carbon Nanotube Field Electron Emitter

A cold cathode X-ray tube was fabricated using a carbon nanotube (CNT) field electron emitter made by a free-standing CNT film which is composed of a highly packed CNT network. A lot of CNT bundles with a sharp tip are vertically aligned at the edge of the thin CNT film with a length of 10 mm and a thickness of 7 mu m. The cold cathode X-ray tube using the CNT field emitter presents an extremely high tube current density of 152 A/cm(2) (corresponding to tube current of 106.4 mA), the electron beam transmittance of 95.2% and a small focal spot size (FSS) of 0.5 mm. In addition, the cold cathode X-ray tube also shows stable lifetime during 100 000 shots. High emission current density of the cold cathode X-ray tube is mainly attributed to a lot of electron emission sites at an edge of the CNT film. The small FSS is caused by an ensemble of the CNT field electron emitter made by a free-standing thin CNT film and the optimized curve-shape elliptical focusing lens. Based on obtained results, the cold cathode X-ray tube can be widely used for various X-ray applications such as medical diagnosis systems and security check systems in the future.

Automated summary

A cold cathode X-ray tube utilizing a carbon nanotube field emitter was developed, exhibiting high tube current density, high electron beam transmittance, and small focal spot size. Additionally, the tube showed stable lifetime and can be widely used in various X-ray applications in the future.