KR20120136180A - X-ray tube having vacuum exhaust structure, anode unit of x-ray tube, and method of manufacturing anode unit for vacuum exhaust of x-ray tube - Google Patents

Abstract

PURPOSE: An x-ray tube, an anode part thereof, and a manufacturing method of the anode part are provided to discharge internal gas by forming a vacuum exhaust path and a vacuum exhaust pipe. CONSTITUTION: A cathode part comprises electron emitter which emits an electronic beam. A grid(160) has a cylinder structure. Vacuum exhaust paths(215,220) are formed in a body of the anode part. A vacuum exhaust pipe(230) is connected to the vacuum exhaust paths. The vacuum exhaust pipe makes the inner side of an x-ray tube vacuous. [Reference numerals] (AA) Electron beam; (BB) X-ray

Description

X-ray tube having vacuum exhaust structure, anode unit of x-ray tube, and method of production of X-ray tube, anode part of X-ray tube, and anode part for vacuum exhaust of X-ray tube manufacturing anode unit for vacuum exhaust of x-ray tube}

The present invention relates to an X-ray tube, and more particularly, to an X-ray tube having a vacuum exhaust structure, an anode portion of an X-ray tube having a vacuum exhaust structure, and an anode portion for vacuum exhaust of an X-ray tube. It is about.

The X-ray tube is provided with a cathode part and an anode part inside a vacuum-sealed glass bulb, and electrons generated at the cathode part are accelerated by a high voltage applied between the cathode part and the anode part, thereby being a target that is an anode part. X-rays are generated while colliding with them.

One type of X-ray tube that generates electrons in the cathode portion is an X-ray tube having a hot electron emission cathode that generates electrons by heating tungsten filaments. In the case of X-ray tube using hot electron emission phenomenon, the filament deteriorates as the heating of tungsten filament is repeated, changing the electron emission characteristics, limiting the lifetime of the X-ray tube, and heating the filament to emit hot electrons. Due to thermal problems, the degree of vacuum decreases due to outgassing and internal heating generated from the filament.Tungsten evaporated during the heating of the filament is deposited on the target surface or the inner wall of the vacuum envelope, thereby degrading high pressure insulation and transmitting radiation dose. Can be reduced.

Recently, studies have been actively conducted on X-ray tubes using a field emission phenomenon in which electrons are emitted beyond a potential barrier (work function) on a solid surface when a high electric field is applied instead of a hot electron emission phenomenon. In particular, research on X-ray tubes having a cold cathode using carbon nanotubes (CNT) as an electron emission source has been conducted.

The technical problem to be solved by the present invention is an X-ray tube including an anode portion in which the vacuum exhaust structure for the X-ray tube is integrated (formed), the anode portion of the X-ray tube having a vacuum exhaust structure, and the vacuum of the X-ray tube It is to provide a method for producing an anode part for exhausting.

In order to achieve the above technical problem, the X-ray tube having a vacuum exhaust structure according to an embodiment of the present invention, the cathode portion including an electron emission source for emitting an electron beam; And an anode portion collided by the electron beam to generate X-rays, the anode portion being formed on a body of the anode portion and configured to vacuum the inside of the X-ray tube; And a vacuum exhaust pipe connected to the vacuum exhaust passage and disposed outside the body of the anode portion, and configured to vacuum the inside of the X-ray tube.

After the gas existing in the X-ray tube is discharged, the intermediate portion of the vacuum exhaust pipe may be compressed and sealed and then cut.

The material of the anode part may be oxygen free copper, and the material of the vacuum exhaust pipe may be oxygen free copper. The vacuum exhaust passage may be connected between a first vacuum exhaust passage passing through an upper portion of the body of the anode portion and a lower portion of the body of the anode portion, and between the first vacuum exhaust passage and the vacuum exhaust pipe and define a side surface of the body of the anode portion. And a second vacuum exhaust passage therethrough.

The anode portion may be cast by a mold having a reverse image of the anode portion.

In order to achieve the above technical problem, the anode portion of the X-ray tube having a vacuum exhaust structure according to an embodiment of the present invention, is formed in the body of the anode portion included in the X-ray tube for making the inside of the X-ray tube into a vacuum A vacuum exhaust passage; And a vacuum exhaust pipe connected to the vacuum exhaust passage and disposed outside the body of the anode portion, and configured to vacuum the inside of the X-ray tube.

In order to achieve the above technical problem, according to an embodiment of the present invention, the manufacturing method of the anode part for the vacuum exhaust of the X-ray tube, (a) a first vacuum penetrating the upper portion of the body of the anode portion and the lower portion of the body of the anode portion Forming an exhaust passage; (b) forming a second vacuum exhaust passage connected to the first vacuum exhaust passage and penetrating the side of the body of the anode portion; And (c) connecting a vacuum exhaust pipe disposed outside the body of the anode to the second vacuum exhaust passage.

In the manufacturing method of the anode part for evacuating the X-ray tube, (d) after discharging the gas inside the X-ray tube through the vacuum exhaust pipe, the intermediate part of the vacuum exhaust pipe is sealed and then cut It may further include.

The manufacturing method of the X-ray tube, the anode portion of the X-ray tube, and the anode portion for vacuum evacuation of the X-ray tube having the vacuum exhaust structure according to the present invention may be made of the material, form, or shape of the vacuum envelope of the X-ray tube. Regardless of the structure, a vacuum exhaust passage formed in the body of the anode portion (anode target) and a vacuum exhaust pipe disposed outside the body of the anode portion can be used for vacuum exhaust of the X-ray tube. Therefore, the present invention allows the inside of the X-ray tube to be easily vacuumed by discharging the gas inside the X-ray tube when the vacuum packaging process of the X-ray tube is performed.

Since the present invention forms a vacuum exhaust passage and a vacuum exhaust pipe at the anode portion of the X-ray tube, when the present invention is applied, the structure (pinch-off or tip-off) of the vacuum exhaust pipe is simplified and the sealing process is performed. Can be facilitated.

According to the present invention, since the material of the anode part may be implemented using oxygen free copper, the vacuum packaging process may be unified with a process using an oxygen free copper vacuum exhaust structure.

In addition, the present invention can implement the material of the anode portion with oxygen-free copper having high thermal conductivity and excellent workability, thereby facilitating the manufacture of a vacuum exhaust structure integrated with the anode portion by using the soft property of the oxygen-free copper.

In order to more fully understand the drawings used in the detailed description of the invention, a brief description of each drawing is provided.
1 is a cross-sectional view illustrating an X-ray tube 100 having a vacuum exhaust structure according to an embodiment of the present invention.
2 is a view for explaining an example of a method for sealing the vacuum exhaust pipe 230 shown in FIG.
3 is a view showing a vacuum exhaust pipe 230 manufactured by an example of a method of sealing the vacuum exhaust pipe shown in FIG.
4 is a view showing the right side of the vacuum exhaust pipe 230 shown in FIG.

In order to fully understand the present invention and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate embodiments of the present invention and the contents described in the accompanying drawings.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail by explaining embodiment of this invention with reference to attached drawing. Like reference numerals in the drawings denote like elements.

Before describing the present invention, a comparative example of the present invention will be described as follows. In the X-ray tube compared with the present invention, a method for evacuating the inside of a glass bulb (glass tube) for encapsulation of a cathode portion and an anode portion is as follows. After generating a pipe on the glass bulb (eg, the surface of the glass bulb), a vacuum pump is connected to the pipe to discharge a gas such as air to make the inside of the glass bulb into a vacuum. The pipe is then sealed.

1 is a cross-sectional view illustrating an X-ray tube 100 having a vacuum exhaust structure according to an embodiment of the present invention.

Referring to FIG. 1, an X-ray tube 100 having a vacuum exhaust structure includes an envelope 110, a cathode portion, a grid (or gate) 160, and an anode portion. . X-ray tube 100 may have a cylindrical structure.

The X-ray tube 100 of FIG. 1 has a triode type structure having a cathode, a grid 160, and an anode as electrodes. The X-ray tube 100 may be, for example, an X-ray tube based on field emission, or an X-ray tube having a hot electron emitting cathode, as shown in FIG. 1.

Envelope (vacuum envelope) 110 surrounds and seals the cathode, grid 160 and anode. The outer shell 110 shown in FIG. 1 surrounds a part of the anode part, but in another embodiment of the present invention, the entire body 200 of the anode part may be surrounded. The material of the shell 110 may be, for example, glass, ceramic, or metal. Sheath 110 may also be referred to as a housing or body.

The cathode portion includes a substrate 140 and an electron emission source 150. The negative electrode portion may have a cylindrical structure. The conducting unit 130 serves as a power supply line for applying power to the cathode. The material of the conductive part 130 may be, for example, stainless alloy, iron, or tungsten.

The substrate 140 may be formed using a material such as metal, silicon, graphite, or the like as the conductive substrate.

The electron emission source 150 emits an electron beam (electrons) and is mounted (installed) on the substrate 140. The electron emission source 150 may be made of a field emission nanomaterial, and the nanomaterial (nanostructure material) may include carbon nanotubes (CNTs), graphene, and nanofibers. , Nanowires, nanorods, nanoneedles, and nanopins. Therefore, the cathode part may also be referred to as a nano emitter.

The carbon nanotube 150 has an electron emission voltage of 1 to 3 (V / ㎛), which is about ten times lower than other metal tips, and thus has excellent field emission characteristics (electron emission efficiency). It is widely used as a material of electron emission source of a tube.

The carbon nanotubes 150 may be grown on the substrate 140 by a screen printing method or a chemical vapor deposition (CVD) method. Referring to the process of growing the carbon nanotubes by the screen printing method, after applying a silver paint (silver paint) on the upper front surface of the substrate 140 using a spray gun (spray gun) carbon nanotube powder By repeatedly spraying 2 to 3 times, an appropriate amount of carbon nanotubes can be grown to be evenly applied on the substrate 140.

Referring to the process of growing carbon nanotubes by CVD method, a buffer layer such as TiN and a catalyst such as Ni or Fe are coated on the substrate 140 and then etching is performed with a gas such as argon or helium. After the seed particles (seed particle) to generate a carbon nanotube source gas such as C ₂ H _{2 It} is possible to grow the carbon nanotubes.

The grid 160 may be disposed (installed) to be spaced apart from the cathode and may be made of metal. The grid 160 serves to extract electrons from the electron emission source 150, and when the focusing unit is integrated with the grid 160, the grid 160 serves as a focusing lens, which is an electrical lens rather than an optical lens. The electron beam is focused on the anode part by changing the direction of the electron beam emitted from the electron emission source 150. The grid 160 includes holes through which the electron beam emitted from the electron emission source 150 passes, as shown in FIG. 1. Each of the holes formed in the grid 160 may have the same size. Grid 160 may have a cylindrical structure. The conductive part 120 serves as a power supply line for applying power to the grid 160. The conductive part 120 may be made of copper, stainless alloy, iron, or tungsten. The conductive part 120 may have a cylindrical structure.

When a voltage is applied between the cathode portion (or the substrate 140) and the anode portion, electrons are emitted from the electron emission source 150 of the cathode portion by an electric field to generate an electron beam. The generated electron beam is extracted by the grid 160 and collides with the target 210 of the anode to generate X-rays. X-rays are emitted to the outside through a window (not shown) formed in the shell 110. The target 210 of the anode part is a portion in which electrons collide directly, and may be formed of a material such as oxygen free copper, copper, molybdenum, or tungsten.

For example, a high voltage of 70 kV may be applied between the cathode portion (substrate 140 of the anode portion) and the anode portion, and a voltage of several kV may be applied between the grid 160 and the cathode portion. . The ground voltage may be applied to the cathode portion.

The anode portion is bombarded by the electron beam to generate X-rays. The anode portion may have a cylindrical structure having an inclined surface. The material of the anode portion may be, for example, oxygen-free copper. Oxygen-free copper refers to high purity copper that contains little oxygen or deoxidizer or impurities. It is generally produced by melt casting in vacuum, oxygen content is about 10 ~ 20ppm, and the property is excellent in electrical conductivity, hydrogen embrittlement, and processability combined with the advantages of tarp pitch copper and phosphorus phosphate copper.

The conductive part may be connected to the upper right side of the body 200 of the anode part which is outside of the outer shell 110. The conductive portion serves as a power supply line for applying power to the anode portion. The material of the conductive portion may be, for example, tungsten or copper.

The anode portion includes the vacuum exhaust passages 215 and 220 and the vacuum exhaust pipe 230. The vacuum exhaust passages 215 and 220 and the vacuum exhaust pipe 230 constitute a vacuum exhaust structure according to the present invention. That is, the present invention includes a positive electrode portion in which the vacuum exhaust structure and the positive electrode portion are integrated.

The vacuum exhaust passages 215 and 220 are formed in the body of the anode portion and serve to vacuum the inside of the X-ray tube 100 (or the inside of the shell 110 of the X-ray tube 100). Do this. The vacuum exhaust passages 215 and 220 include a first vacuum exhaust passage 215 and a second vacuum exhaust passage 220. The first vacuum exhaust passage 215 penetrates an upper portion of the body 200 of the anode portion and a lower portion of the body 200 of the anode portion. The second vacuum exhaust passage 220 is connected between the first vacuum exhaust passage 215 and the vacuum exhaust pipe 230 and passes through the side (right side) of the body 200 of the anode portion. The side surface of the body 200 of the anode portion is a surface opposite to the surface on which the target 210 of the anode portion is located.

In another embodiment of the present invention, the first vacuum exhaust passage does not penetrate the upper portion of the body 200 of the anode portion but penetrates only the lower portion of the body 200 of the anode portion. The second vacuum exhaust passage 220 is connected between the first vacuum exhaust passage and the vacuum exhaust pipe 230 and passes through the side surface of the body 200 of the anode portion.

The vacuum exhaust passage according to the present invention, in the body 200 of the anode portion to have a structure of the passage (path) through which the gas existing in the interior of the X-ray tube 100 before the vacuum packaging process including the vacuum exhaust process It can be manufactured in various forms (structures).

The vacuum exhaust pipe 230 is connected to the vacuum exhaust passages 215 and 220 and is disposed outside the body 200 of the anode part and coupled to the side of the body 200 of the anode part. The vacuum exhaust pipe 230 is a pipe for making the inside of the X-ray tube 100 into a vacuum. The material of the vacuum exhaust pipe 230 may be, for example, oxygen-free copper.

An embodiment of a vacuum packaging process for evacuating gas inside the X-ray tube 100 using the vacuum exhaust passages 215 and 220 and the vacuum exhaust pipe 230 is described as follows.

A vacuum pump or pumping station is connected to the end part (right end) of the vacuum exhaust pipe 230. When the vacuum pump is driven (operated), the gas inside the X-ray tube 100 is taken in (exhausted) through the vacuum exhaust passages 215 and 220 and the vacuum exhaust pipe 230. After the gas present in the inside of the X-ray tube 100 is completely discharged by the vacuum pump, the intermediate part of the vacuum exhaust pipe 230 is compressed and sealed and then cut. The vacuum exhaust pipe 230 is then pinch-off as indicated at 240 in FIG. 1. The sealing process and the cutting process can be performed by a pinch-off tool. The X-ray tube 100 is then sealed in a sealed state.

A method of manufacturing the anode portion for evacuating the X-ray tube 100 according to the embodiment of the present invention is described as follows with reference to FIG. 1. The manufacturing method of the anode portion includes a first vacuum exhaust passage forming step, a second vacuum exhaust passage forming step, and a connecting step.

According to the first vacuum exhaust passage forming step, the upper part of the body 200 of the anode part and the body 200 of the anode part by a drilling process using a drill-like tool or a laser process using a laser beam. A first vacuum exhaust passage 215 penetrating the lower portion is formed. The body 200 of the anode part may be made of, for example, oxygen-free copper.

According to the second vacuum exhaust passage forming step, the first vacuum exhaust passage 215 is connected to the first vacuum exhaust passage 215 by a drilling process using a drill-like tool or a laser process using a laser beam and penetrates the side surface of the body 200 of the anode portion. Two vacuum exhaust passages 220 are formed.

According to the connecting step, the vacuum exhaust pipe 230 disposed outside the body 200 of the anode part is connected (coupled) to an end part 225 of the second vacuum exhaust passage 220 by a welding process. . In the welding process, a fusion weld method using electric heat may be used. The vacuum exhaust pipe 230 may be made of, for example, oxygen-free copper.

The manufacturing method of the anode part for evacuating the X-ray tube may further include a sealing step. According to the sealing step, after the gas inside the X-ray tube 100 is completely discharged through the vacuum exhaust pipe 230 by using a vacuum pump, the middle portion of the vacuum exhaust pipe 230 is subjected to a pinch-off process. It is pressed by a pinch-off tool used for sealing, and then sealed (sealed) and then cut.

In the manufacture of the anode portion for vacuum evacuation of the X-ray tube 100 according to the embodiment of the present invention, the anode portion shown in FIG. 1 is cast by using a mold having a reverse image of the anode portion. Can be That is, the anode portion of FIG. 1 can be manufactured by injecting, for example, oxygen-free copper into the mold through the opening of the mold. The mold may be, for example, a metallic pattern. The anode portion may be cast by a mold having a reverse phase (or image reversal pattern) of the vacuum exhaust passages 215 and 220 and a reverse phase of the vacuum exhaust pipe 230. When the body 200 of the anode portion in which the vacuum exhaust paths 215 and 220 are formed and the vacuum exhaust pipe 230 are manufactured together by the above-described casting method, the inner surface of the vacuum exhaust pipe 230 may be relatively clean. Can be.

Meanwhile, although a tripolar structure is illustrated in FIG. 1, the present invention may have a dipole type structure in which a cathode part and an anode part are used as electrodes.

In the bipolar structure, a high voltage of, for example, 70 kV may be applied between the cathode portion and the anode portion, and a focusing portion disposed on the cathode portion spaced from the cathode portion and serving as a focusing lens. The same voltage as that of the cathode may be applied. The focusing part may be a metal material. The structure and shape of the focusing part may be similar to the structure and shape of the grid 160.

Since the tripolar structure includes a grid or gate portion, it is possible to more easily control the emission current emitted from the electron emission source than the bipolar structure. The gate portion extracts the electron beam (electrons) emitted from the electron emission source 150 and focuses the extracted electron beam on the anode portion. That is, the gate part may perform an extraction function of electrons, a function of focusing electrons to change the trajectory of the electron beam, and may also perform a function of inducing emission of electrons from the electron emission source 150.

Although an X-ray tube of a reflective structure having a reflective anode portion is shown in FIG. 1, the present invention can be applied to an X-ray tube of a transparent structure having a transparent anode portion.

2 is a view for explaining an example of a method for sealing the vacuum exhaust pipe 230 shown in FIG.

Referring to FIG. 2, the middle portion of the vacuum exhaust pipe 230 may be sealed by cylindrical jaws of a pinch-off tool. An end portion of the sealed vacuum exhaust pipe 230 is cold welded. Cold welding is a method of welding nonferrous metals and nonferrous metal alloys without the use of heat, electricity, charging stations and solvents.

3 is a view showing a vacuum exhaust pipe 230 manufactured by an example of a method of sealing the vacuum exhaust pipe shown in FIG. 4 is a view showing the right side of the vacuum exhaust pipe 230 shown in FIG.

3 and 4, it can be seen that the end 240 of the vacuum exhaust pipe 230 is compressed to seal the vacuum exhaust pipe 230.

Therefore, the manufacturing method of the X-ray tube having the vacuum exhaust structure according to the present invention, the anode portion of the X-ray tube, and the anode portion for vacuum exhaust of the X-ray tube is related to the material, form, or structure of the vacuum shell of the X-ray tube. The vacuum exhaust passage formed in the body of the anode portion and the vacuum exhaust pipe disposed outside the body of the anode portion can be used for the vacuum exhaust of the X-ray tube without. Therefore, the present invention allows the inside of the X-ray tube to be easily vacuumed by discharging the gas inside the X-ray tube when the vacuum packaging process of the X-ray tube is performed.

Since the present invention forms a vacuum exhaust passage and a vacuum exhaust pipe at the anode portion of the X-ray tube, when the present invention is applied, the structure for sealing vacuum exhaust can be simplified and the sealing process can be facilitated.

According to the present invention, the material of the anode portion may be implemented using oxygen-free copper, and thus the vacuum packaging process may be unified with a process using an oxygen-free copper vacuum exhaust structure.

According to the present invention, since the material of the anode portion can be implemented with oxygen-free copper having high thermal conductivity and excellent workability, it is possible to facilitate the manufacture of a vacuum exhaust structure integrated with the anode portion by using the soft property of the oxygen-free copper.

As described above, the embodiments have been disclosed in the drawings and specification. Although specific terms are used herein, they are used for the purpose of describing the present invention only and are not used to limit the scope of the present invention described in the claims or the claims. Therefore, it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible from the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

110: sheath
200: body of the anode portion
215: first vacuum exhaust passage
220: second vacuum exhaust passage
230: vacuum exhaust pipe
240: end

Claims (9)

A cathode including an electron emission source for emitting an electron beam; And
An anode portion collided by the electron beam to generate X-rays,
The anode portion,
A vacuum exhaust passage formed in the body of the anode and for vacuuming the inside of the X-ray tube; And
And a vacuum exhaust pipe connected to the vacuum exhaust passage and disposed outside of the body of the anode, for evacuating the inside of the X-ray tube. The method of claim 1,
And after the gas existing in the X-ray tube is discharged, the intermediate portion of the vacuum exhaust pipe is compressed and sealed and then cut. The method of claim 1,
The material of the anode portion is oxygen-free copper (oxygen free copper), the material of the vacuum exhaust pipe is oxygen-free copper X-ray tube. The method of claim 1,
The vacuum exhaust passage may be connected between a first vacuum exhaust passage passing through an upper portion of the body of the anode portion and a lower portion of the body of the anode portion, and between the first vacuum exhaust passage and the vacuum exhaust pipe and define a side surface of the body of the anode portion. An X-ray tube comprising a penetrating second vacuum exhaust passage. The method of claim 1,
The vacuum exhaust passage may include a first vacuum exhaust passage passing through a lower portion of the body of the anode portion, and a second vacuum exhaust passage connected between the first vacuum exhaust passage and the vacuum exhaust pipe and passing through a side surface of the body of the anode portion. X-ray tube comprising a. The method of claim 1,
And the anode portion is cast by a mold having a reverse image of the anode portion. A vacuum exhaust passage formed in the body of the anode portion included in the X-ray tube and configured to vacuum the inside of the X-ray tube; And
An anode part of the X-ray tube connected to the vacuum exhaust passage and disposed outside of the body of the anode portion, and including a vacuum exhaust pipe for vacuuming the inside of the X-ray tube. (a) forming a first vacuum exhaust passage passing through an upper portion of the body of the anode portion and a lower portion of the body of the anode portion;
(b) forming a second vacuum exhaust passage connected to the first vacuum exhaust passage and penetrating the side of the body of the anode portion; And
and (c) connecting a vacuum exhaust pipe disposed outside of the body of the anode portion to the second vacuum exhaust passage. The method of claim 8, wherein the manufacturing method of the anode portion for evacuating the X-ray tube,
(d) manufacturing a positive electrode portion for the X-ray tube further comprising the step of discharging the gas inside the X-ray tube through the vacuum exhaust pipe, pressing and sealing the intermediate portion of the vacuum exhaust pipe, and cutting the gas.

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