High definition X-ray Source based on Carbon Nanotube Emitter for Micro CT application

Xiaobing LI 1, Menglong LIU 1, Juntao ZHOU 1, Xuanyi WU 1, Qingyang WU 2,

Liang REN 2, Jiewen ZHENG 2, Zexiang CHEN 2

1 University of Electronic Science and Technology of China, Chengdu, China

2 Guangzhou Haozhi Imaging Technology, Guangzhou, China

Abstract. A micro-focus CNT-based X-ray tube was developed successfully, in

which CNT circular rings grown by microwave plasma CVD employed field emission

cathode to obtain large and stable emission current. The size of the CNT ring is 50

micrometer in diameter and the wall thickness is 2 micro meter. A high convergence

ratio electron gun with grid gate and focus electrode was designed for this X-ray tube

to achieve a micron level X-ray focal spot. The full vacuum-sealed micro-focus CNTbased

X-ray tube exhibited a very small focal spot with a diameter of about 5 micro

meters and stable current of more than 50 μA, the corresponding average field

emission current density of the CNT emitter is more than 2.55A/cm2. The X-ray

images of IC indicated this CNT x-ray source is competent for high definition DR and

micro CT application.

Keywords: Carbon Nanotube, Field Emission, X-ray Tube, Micro-focus spot..