X-ray source for medical testing and mobile CT (computer tomography) scanner

Abstract

The invention provides an X-ray source for medical testing and a mobile CT (computer tomography) scanner. The X-ray source for medical testing comprises an X-ray tube and a high voltage generator, wherein the X-ray tube comprises an anode, a cold cathode, a grid and a tube shell; the tube shell is used for supporting the anode, the cold cathode and the grid, and enabling a vacuum working environment of the anode, the cold cathode and the grid to be insulated from the outside world, and the anode is grounded; and the high voltage generator is used for providing a first electric field between the cold cathode and the grid so as to enable the cold cathode to emit electrons in a field mode, and providing a second electric field between the grid and the anode so as to accelerate the electrons emitted by the cold cathode, thereby enabling the electrons to bombard X-rays generated by the anode. The X-ray source provided by the invention can realize high-frequency pulse transmission of electron beams easily, and is high in response speed, long in service life and high in security, that is, the overall performance of the X-ray source is improved, thereby being better meeting practical application requirements such as medical testing and the like.

Description

technical field [0001] The invention relates to the field of medical equipment, in particular to an X-ray source for medical detection and a mobile CT scanner. Background technique [0002] With the development of medical science and technology, various medical computer tomography (Computer tomography; CT) devices have emerged. Among them, X-ray tube is a key component of small medical CT equipment. The cathode is the core component of the X-ray tube, which directly determines the performance of the X-ray tube, the quality of imaging such as resolution and contrast, and the working efficiency of the whole machine. [0003] In the prior art, the X-ray tube is usually based on the thermal emission of tungsten (W) wire, that is, the cathode of the X-ray tube is made of tungsten (W) wire, and its working principle is that the tungsten (W) wire is heated to its working temperature When electrons are emitted, the thermally emitted electrons bombard the anode, thereby generating ...

AI Technical Summary

Problems solved by technology

[0004] The prior art X-ray tube based on tungsten (W) filament thermal emission has at least the following disadvantages: the tungsten used in the cathode of the existing X-ray tube has a high electron work function (φw=4.52eV), and the emission current density is small , when the pure tungsten material is at 2200 ℃, its thermal emission current density is only 0.3A / cm2

If you want to obtain a larger total emission current, you usually increase the cathode temperature, but increasing the cathode temperature will increase the evaporation rate of the cathode material, and the evaporation of the cathode material will make the tungsten wire thinner, and the thinner tungsten wire cathode will make As the temperature of the cathode increases, the evaporation of the cathode intensifies, thus forming a vicious cycle; in addition, the evaporated tungsten cathode material will be deposited on the tube shell, forming a continuous or intermittent tungsten conductive film, which destroys the dielectric strength of the X-ray tube and makes the tube The pressure drops and the tube is scrapped, which reduces the life of the X-ray tube; at the same time, this tungsten conductive film also blocks the X-ray intensity of the output window, reducing the imaging sensitivity

Therefore, the overall performance of the existing X-ray tube based on tungsten (W) filament thermal emission is poor, and it is urgent to study a new type of cold cathode X-ray tube to replace the existing X-ray tube based on thermal tungsten (W) filament

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