Method for manufacturing cold cathode x-ray tube

Abstract

The present invention provides a method for manufacturing a cold cathode X-ray tube. The method comprises: cutting performance-optimized Buckypaper into a required structure having a specific shape; reliably connecting the Buckypaper cut into the specific shape to a substrate composed of a metal or alloy, and forming a cathode assembly by means of fixed assembly; assembling the cathode assembly according to the electron emission requirements of an X-ray tube to form a cathode emitter; and mounting the assembled cathode emitter into a cathode slot, and sealing the cathode emitter together with an anode target material in a housing to form a cold cathode X-ray tube. The present invention can prolong the service life of X-ray tubes, improve reliability and stability, and facilitate heat dissipation; and in addition, the X-ray tubes can withstand a higher electric field force, thereby generating a higher dose of X-rays.

Description

Method for manufacturing a cold cathode X-ray tube TECHNICAL FIELD

[0001] The present application relates to the technical field of X-ray tube, and particularly relates to a method for manufacturing a cold cathode X-ray tube. BACKGROUND

[0002] An X-ray tube is a vacuum diode working at high voltage, which comprises two electrodes: one is a filament for emitting electrons as a cathode; the other is a target for accepting electron bombardment as an anode. Both electrodes are sealed in a high-vacuum glass or ceramic envelope. The power supply part of the X-ray tube comprises at least a low-voltage power supply for heating the filament and a high-voltage generator for applying high voltage to both electrodes. When the filament is supplied with sufficient current to generate an electron cloud, and sufficient voltage (kV level) is applied between the anode and the cathode, the electron cloud is pulled to the anode. At this time, the electrons generated by the cathode impact the anode target at high energy and high speed. When the high-speed electrons reach the target surface, their kinetic energy is suddenly converted into radiation energy in the form of X-rays.

[0003] At present, the cathode of the X-ray tube usually adopts carbon nanotubes in the following two ways: 1. growing carbon nanotubes directly on a substrate; and 2. depositing carbon nanotubes on a substrate.

[0004] The above two ways have the following defects:

[0005] For the way 1, when field emission occurs, the carbon nanotubes are easily pulled out and damaged due to strong electric field force;

[0006] For the way 2, when field emission occurs, the emitter is easily fused due to overheating caused by too large emission current. SUMMARY

[0007] The method for manufacturing a cold cathode X-ray tube provided by the present application has the advantages that the cold cathode X-ray tube manufactured by the method has a long service life, high reliability and stability, and is easy to dissipate heat; and can withstand higher electric field force, thereby generating higher dose of X-rays.

[0008] In a first aspect, the present application provides a method for manufacturing a cold cathode X-ray tube, comprising:

[0009] cutting the performance-optimized Buckypaper into a structure with a specific shape;

[0010] reliably connecting the Buckypaper cut into the structure with the specific shape with a substrate composed of metal or alloy, and forming a cathode assembly by fixing and assembling;

[0011] assembling the cathode assembly according to the requirements of the X-ray tube for electron emission, and forming a cathode emitter;

[0012] The assembled cathode emitter is assembled to a cathode slot and sealed in an outer shell together with an anode target to form a cold cathode X-ray tube.

[0013] Optionally, the performance optimization comprises: performance optimization in a high-temperature treatment mode.

[0014] Optionally, the high-temperature treatment mode comprises a direct heating mode or an indirect heating mode, and the indirect heating mode comprises laser, high temperature, electric furnace or induction heating.

[0015] Optionally, the cutting of the performance-optimized Bakelite paper into a structure with a specific shape comprises: cutting of the performance-optimized Bakelite paper into a structure with a specific shape by a mechanical cutting or laser cutting mode.

[0016] Optionally, the specific shape comprises a comb shape, a sawtooth shape, a strip shape or a corrugated shape.

[0017] Optionally, before the cutting of the performance-optimized Bakelite paper into a structure with a specific shape, the method further comprises:

[0018] Adding a material with a low work function in the Bakelite paper.

[0019] Optionally, the material with a low work function comprises at least one of the following materials: barium oxide, cesium oxide, scandium oxide, yttrium oxide, lanthanum boride, hafnium carbide and tantalum carbide.

[0020] Optionally, the adding of the material with a low work function in the Bakelite paper comprises: adding of the material with a low work function in the Bakelite paper by in-situ reaction through plating or by a direct physical deposition and / or chemical deposition mode, so as to form a good composite with the Bakelite paper.

[0021] The preparation method of the cold cathode X-ray tube provided by the embodiment of the application uses the cathode made of the Bakelite paper, the interaction force between the carbon nanotubes is stronger, the carbon nanotubes are not easy to pull out and damaged, the service life of the X-ray tube is longer, the reliability and stability are higher, and the X-ray tube is easier to dissipate heat; the X-ray tube can withstand a higher electric field force, thereby generating a higher dose of X-rays. BRIEF DESCRIPTION OF DRAWINGS

[0022] FIG. 1 is a flowchart of the preparation method of the cold cathode X-ray tube according to an embodiment of the application;

[0023] FIG. 2 is a schematic structural diagram of the cold cathode X-ray tube according to an embodiment of the application. DETAILED DESCRIPTION

[0024] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0025] The embodiments of the present application provide a preparation method of a cold cathode X-ray tube, as shown in FIG. 1, and the method comprises the following steps:

[0026] In step S11, the performance-optimized Buckypaper is cut into a structure with a specific shape.

[0027] Since the performance of the directly prepared Buckypaper is poor, the carbon nanotubes need to be chemically or mechanically treated, which causes a large number of defects or functional groups in the carbon nanotubes, and the emission stability and reliability are poor when used as an electron emission source. Therefore, some measures need to be taken to optimize the performance of the carbon nanotubes to improve the quality of the carbon nanotubes. In the embodiments, a high-temperature treatment method is used for performance optimization, so that the defects existing in the carbon nanotubes can be better removed or repaired at high temperature, and the functional groups can be completely removed, so that the Buckypaper emitter with excellent performance is obtained.

[0028] The high-temperature treatment method can be a direct heating method or an indirect heating method, such as a laser, high temperature, electric furnace, induction heating, etc.

[0029] Specifically, the performance-optimized Buckypaper can be cut into a structure with a specific shape by mechanical cutting or laser cutting, etc.

[0030] The specific shape can be a comb shape, a sawtooth shape, a strip shape, a corrugated shape, etc.

[0031] In step S12, the Buckypaper cut into a structure with a specific shape is reliably connected with a substrate composed of a metal or an alloy, and a cathode assembly is formed by fixing and assembling.

[0032] In step S13, the cathode assembly is assembled according to the requirements of the X-ray tube for electron emission to form a cathode emitter.

[0033] In step S14, the assembled cathode emitter is assembled into a cathode groove, and is sealed in an outer shell together with an anode target material to form a cold cathode X-ray tube.

[0034] Further, barium oxide, cesium oxide, scandium oxide, yttrium oxide, lanthanum boride, hafnium carbide, tantalum carbide and other materials with low work function can be added to the barium paper to reduce the work function of the barium paper cathode emitter. Specifically, the above-mentioned materials can be in-situ reacted by coating, or directly physically deposited and / or chemically deposited to form a good composite with the barium paper.

[0035] The preparation method of the cold cathode X-ray tube provided by the embodiment of the present application uses the cathode made of the barium paper by the above method, the interaction force between the carbon nanotubes is stronger, the carbon nanotubes are not easy to be pulled out and damaged, the service life of the X-ray tube is longer, the reliability and stability are higher, and the X-ray tube is easier to dissipate heat; the X-ray tube can withstand a higher electric field force, thereby generating a higher dose of X-rays.

[0036] The cold cathode X-ray tube provided by the embodiment of the present application includes: a shell 11, and a barium paper cathode emitter 12 and an anode target material 13 located inside the shell 11, the inside of the shell 11 is in a high vacuum state, the barium paper cathode emitter 12 is made of barium paper prepared based on carbon nanotubes; the barium paper cathode emitter 12 generates electrons under the action of an applied electric field and bombards the anode target material 13 to generate X-rays.

[0037] The cold cathode X-ray tube provided by the embodiment of the present application uses the cathode emitter made of the barium paper, the density is high, the interaction force between the carbon nanotubes is strong, the carbon nanotubes are not easy to be pulled out and damaged, the service life of the X-ray tube is longer, the reliability and stability are higher, and the X-ray tube is easier to dissipate heat; and the X-ray tube can withstand a higher electric field force, thereby generating a higher dose of X-rays.

[0038] Further, barium oxide, cesium oxide, scandium oxide, yttrium oxide, lanthanum boride, hafnium carbide, tantalum carbide and other materials with low work function can be added to the barium paper to reduce the work function of the barium paper cathode emitter.

[0039] Further, the carbon nanotubes in the barium paper cathode material are filled with other materials with high thermal conductivity and high electrical conductivity to further improve the interaction force between the carbon nanotubes and make the barium paper cathode material easier to dissipate heat. Optionally, the material with high thermal conductivity and high electrical conductivity is filled between the carbon nanotubes in the barium paper cathode material by liquid deposition, gas deposition or solid phase compounding.

[0040] The liquid deposition can use some high molecular systems, the gas deposition can use the gas phase form of alkynyl hydrocarbon or alcohol ketone ether, etc.; or use high-carbon-content quasi-solid-state materials such as pitch to be compounded with the barium paper.

[0041] Optionally, the material with high thermal conductivity and high electrical conductivity includes at least one of the following: graphite, graphene, boron nitride, copper, silver, diamond, silicon carbide, sapphire and aluminum nitride.

[0042] The cathode is cut from the performance-optimized Bakelite according to the required shape.

[0043] The embodiment of the present application also provides a CT scanner, which comprises the cold cathode X-ray tube as described above.

[0044] The CT scanner can be applied to the fields of medical treatment, security check, industrial product detection and the like, but is not limited thereto.

[0045] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any change or replacement that can be easily thought of by those skilled in the art within the technical range disclosed by the present application should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of manufacturing a cold cathode X-ray tube, characterized in that, The method comprises: cutting the performance-optimized bakelite into a structure with a specific shape as required; reliably connecting the bakelite cut into a structure with a specific shape with a substrate composed of a metal or an alloy, and forming a cathode assembly by means of fixed assembly; assembling the cathode assembly according to the requirements of an X-ray tube for electron emission, to form a cathode emitter; assembling the assembled cathode emitter into a cathode slot, and sealing it together with an anode target in a shell to form a cold cathode X-ray tube.

2. The method of claim 1, wherein, The performance optimization comprises: performance optimization by means of high-temperature treatment.

3. The method of claim 2, wherein, The high-temperature treatment comprises direct heating or indirect heating, and the indirect heating comprises laser, high temperature, electric furnace or induction heating.

4. The method of claim 1, wherein, The cutting of the performance-optimized bakelite into a structure with a specific shape as required comprises: cutting the performance-optimized bakelite into a structure with a specific shape as required by means of mechanical cutting or laser cutting.

5. The method of claim 4, wherein, The specific shape comprises a comb shape, a sawtooth shape, a strip shape or a corrugated shape.

6. The method of claim 1, wherein, Before the cutting of the performance-optimized bakelite into a structure with a specific shape as required, the method further comprises: adding a material with a low work function to the bakelite.

7. The method of claim 6, wherein, The material with a low work function comprises at least one of the following materials: barium oxide, cesium oxide, scandium oxide, yttrium oxide, lanthanum boride, hafnium carbide and tantalum carbide.

8. The method of claim 6, wherein, The adding of the material with a low work function to the bakelite comprises: adding the material with a low work function to the bakelite by means of in-situ reaction of plating, or by means of direct physical deposition and / or chemical deposition, so as to form a good composite with the bakelite.

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