Focusing type cold cathode X-ray tube

Abstract

The invention discloses a focusing type cold cathode X-ray tube which comprises a field emission cold cathode, a lamp filament gate electrode formed by lamp filaments, an anode, an X-ray tube case and a ray emergence window, wherein the field emission cold cathode and the anode are respectively arranged at two ends inside the X-ray tube case and are respectively extracted to the outside of the X-ray tube case through a cathode extraction electrode and an anode extraction electrode; the lamp filament gate electrode is arranged between the field emission cold cathode and the anode; two side surfaces of the lamp filament gate electrode are extracted to the outside of the X-ray tube case through the two extraction electrodes; the anode is provided with a slope surface for generating an X-ray by electron bombardment; and the ray emergence window is arranged at the position on the side surface of the e X-ray tube case, which is just opposite to the slope surface. Compared with the general field emission cold cathode X-ray tube, the focusing type cold cathode X-ray tube can be used for effectively carrying out electron bombardment on the anode to degass, improving the vacuum degree in the X-ray tube, simultaneously focusing electron beams, improving the performance of the X-ray tube and prolonging the service life of the X-ray tube.

Description

technical field [0001] The invention relates to a cold cathode X-ray tube, in particular to a focusing type cold cathode X-ray tube. Background technique [0002] The traditional X-ray tube uses a filament material such as tungsten wire as the cathode. When the filament is energized and heated, electrons are emitted. Under the high voltage of the anode, the electrons bombard the anode to generate X-rays. However, the application of traditional X-ray tubes in high-end imaging equipment is limited due to the heating of the filament and the low emission current of the filament. In recent years, field emission cold cathodes have been initially applied in vacuum devices such as X-ray tubes because of their characteristics such as no need for heating, rapid response, and high emission current density. An X-ray tube using a silicon microtip and a diamond film field emission array has been realized in the laboratory. X-ray tubes using nano-materials such as carbon nanotubes and na...

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Problems solved by technology

[0004] For X-ray tubes using field emission cold cathodes, electron emission from the cathode needs to be at a high voltage when the anode is close to work. Under this voltage, the anode has already produced X-rays, which will bring radiation effects to the operator. At the same time, the defocusing of electrons is not enough, the area of ​​electrons acting on the anode is small, and the degassing of the anode is not very sufficient. The poor atmosphere in the tube will directly affect the performance and life of the X-ray tube.

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