X-ray tube based on thermal emission of LaB6 nano material and mobile CT (computer tomography) scanner

Abstract

The invention provides an X-ray tube based on thermal emission of a LaB6 nano material and a mobile CT (computer tomography) scanner. The X-ray tube based on thermal emission of the LaB6 nano material comprises a positive electrode, a negative electrode and a tube shell, wherein the tube shell is used for supporting the positive electrode and the negative electrode and enables a working environment of the positive electrode and the negative electrode to be insulated from the outside world, thereby keeping the working environment to be vacuum; the negative electrode is made of the LaB6 nano material, and electrons of thermal emission bombard the positive electrode when the negative electrode is heated to the working temperature of the LaB6 nano material so as to generate X-rays. According to the technical solution of the invention, under the condition of acquiring the same emission current density, the working temperature of the negative electrode made of the LaB6 nano material is lower than that of a negative electrode of a tungsten filament by more than 1000 DEG C through manufacturing the negative electrode by adopting the LaB6 nano material, thereby reducing the evaporation rate of the negative electrode material. In addition, the emission current, the stability and the service life of the adopted thermal emission negative electrode X-ray tube are improved greatly.

Description

technical field [0001] The invention relates to the field of medical devices, in particular to an X-ray tube and a mobile CT scanner based on thermal emission of lanthanum hexaboride (LaB6) nanomaterials. Background technique [0002] With the development of medical science and technology, various medical condition detectors (Computer tomography; CT) equipment have emerged. The X-ray tube is a common 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 Electrons are emitted thermally, and the thermally emitted electrons ...

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 / cm 2

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 prior art X-ray tubes based on tungsten (W) filament thermal emission is poor

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