Microfocus X-ray tube using nano-field emitters

Abstract

To provide a microfocus X-ray tube.SOLUTION: A microfocus X-ray tube has a metal and ceramic laminated junction structure without an exhaust tube using nano field emitters with excellent properties.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a microfocus X-ray tube, and more particularly to an apparatus and method for a microfocus X-ray tube having a structure in which different materials are bonded together. [Background technology]

[0002] Generally, X-ray imaging is a method for precisely inspecting elements and parts with fine structures without destroying them. X-ray imaging uses bremsstrahlung X-rays that are generated when an extremely small, focused electron beam strikes a metal anode target. Here, to observe the internal fine structure, the shadow image of the X-rays that pass through the elements and parts must be enlarged and acquired, and when using a digital X-ray image detector, an appropriate image enlargement process is required due to the limitations of pixel size reduction.

[0003] In other words, in the X-ray imaging method, the shadow image can be enlarged as the distance between the digital X-ray image detector and the X-ray source increases, but the amount of X-rays decreases in inverse proportion to the square of the distance. Therefore, in order to obtain the image enlargement rate and the amount of X-rays, it is advantageous to position the subject adjacent to the X-ray source, i.e., the electron beam focal point of the anode target.

[0004] However, since the anode target is several tens to several hundreds of kV higher than the cathode electrode from which the electron beam is emitted, if the cathode is grounded, the anode electrode will be at a high voltage, making it difficult to bring the subject close to the anode target due to insulation issues. Therefore, a negative power supply cathode structure that grounds the anode electrode, or even if the anode is positive power supply, a grounded window structure is required where the subject comes into contact. An X-ray tube with such a structure is shown in Figure 1.

[0005] In detail, conventional X-ray tubes have a window structure with both power anodes and grounded, a vacuum container is made by joining a glass tube with a metal electrode, and the gas inside is exhausted using an exhaust tube before being sealed. Here, the metal head part is combined with a metal ring fused to the glass bulb, and each electrode of the electron gun is also connected to the outside through a stem structure fused to the glass. Here, when using nano field emitters as the electron source of the electron gun, it is difficult to obtain good characteristics if a vacuum X-ray tube is manufactured using an exhaust tube method with an insulating structure of a glass tube. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a structure for a microfocus X-ray tube having a nano-field emitter realized in the form of a laminate of ceramic insulators and metal electrodes.

[0007] The present invention provides a structure for a microfocus X-ray tube that is high temperature bonded via vacuum brazing directly using a ceramic insulator without an exhaust tube.

[0008] The present invention provides a microfocus X-ray tube structure that uses a grounded window electrode and a positive anode in the head of the microfocus X-ray tube, which can minimize the distance between the target position where the X-rays are generated and the subject. [Means for solving the problem]

[0009] According to one embodiment of the present invention, there is provided a microfocus X-ray tube comprising: a head portion made of a metal material; a ceramic insulating tube bonded to one side of the head portion at high temperature; an electron gun bonded to a side of the head portion and equipped with a nano field emitter; an anode provided in an internal space formed by the high-temperature bonded head portion and the ceramic insulating tube; and a plate-shaped target attached to the node.

[0010] The head unit in one embodiment of the present invention is grounded to a thin plate (sheet)-like window, and the sheet-like window can emit X-rays generated by the electron beam emitted from the electron gun to the outside of the microfocus X-ray tube.

[0011] According to an embodiment of the present invention, the head portion has an insertion tube structure including a recess on one surface of the head portion, and the insertion tube structure is inserted into the ceramic insulation tube and spaced apart from the ceramic insulation tube by an insulation tube alignment guide.

[0012] According to an embodiment of the present invention, the head unit is joined to the insulating ceramic of the electron gun via a joint ring of the electron gun, and the position of the electron gun may be aligned by an electron gun guide formed on a side of the head unit.

[0013] According to an embodiment of the present invention, the ceramic insulating tube is connected to the anode via an anode connection ring, and the position of the ceramic insulating tube may be aligned by an insulating tube guide formed on the node connection ring.

[0014] An electron gun according to an embodiment of the present invention may include a cathode electrode coupled to a cathode plate having the nano field emitters formed thereon, a gate electrode coupled to a gate plate, and a focus electrode coupled to a focus plate.

[0015] In one embodiment of the present invention, the gate plate may be formed with a gate opening for extracting electrons from the nano field emitter, and the focus plate may be formed with a focus opening for accelerating the electrons and focusing the emitted electron beam.

[0016] According to an embodiment of the present invention, the target is bonded to the node by a vacuum brazing material, and the node may have a recess formed therein such that a bonding area is smaller than an area of ​​the target.

[0017] A microfocus X-ray tube according to an embodiment of the present invention may include a head portion joined to an electron gun having a nano field emitter, a ceramic insulating tube joined to the head portion at high temperature, and an anode joined to the ceramic insulating tube and equipped with a plate-shaped target.

[0018] The head unit according to one embodiment of the present invention may include a window for emitting an electron beam emitted from an electron gun to the outside, a diffusion prevention groove for minimizing brazing material in the process of grounding the head unit and the window, and a ring cover arranged along the diffusion prevention groove.

[0019] According to an embodiment of the present invention, the head portion may be formed in an insertion tube structure in which a portion of the head portion is inserted into the ceramic insulating tube.

[0020] In one embodiment of the present invention, the head portion is joined to the insulating ceramic of the electron gun via a joining ring of the electron gun on a side of the head portion, and the position of the electron gun can be aligned by an electron gun guide formed on the side of the head portion.

[0021] According to an embodiment of the present invention, the ceramic insulating tube is connected to the anode via an anode connection ring, and the position of the ceramic insulating tube may be aligned by an insulating tube guide formed on the node connection ring.

[0022] An electron gun according to an embodiment of the present invention may include a cathode electrode coupled to a cathode plate having the nano field emitters formed thereon, a gate electrode coupled to a gate plate, and a focus electrode coupled to a focus plate.

[0023] In one embodiment of the present invention, the gate plate may be formed with a gate opening for extracting electrons from the nano field emitter, and the focus plate may be formed with a focus opening for accelerating the electrons and focusing the emitted electron beam.

[0024] In an embodiment of the present invention, the target may be attached to a node by a recess formed to have a bonding area smaller than an area of ​​the target. Effect of the Invention

[0025] According to one embodiment of the present invention, a microfocus X-ray tube may have a nano field emitter realized in the form of a laminate of a ceramic insulator and a metal electrode.

[0026] According to one embodiment of the present invention, a microfocus X-ray tube can be high temperature bonded via vacuum brazing directly without an exhaust tube using a ceramic insulator.

[0027] According to an embodiment of the present invention, a microfocus X-ray tube uses a grounded window electrode and a positive anode in a microfocus X-ray head, thereby minimizing the distance between a target position where X-rays are generated and a subject. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 illustrates a microfocus X-ray tube according to an embodiment. [Figure 2A] FIG. 2 is a diagram showing voltages at different locations of a microfocus X-ray tube according to an embodiment. [Figure 2B] 1 is a diagram showing a joint structure of a microfocus X-ray tube according to an embodiment; [Figure 2C] FIG. 1 illustrates an electron gun according to an embodiment. [Figure 2D] FIG. 2 illustrates an anode and target according to an embodiment. [Figure 3A] FIG. 2 is a diagram showing a head unit according to an embodiment. [Figure 3B] FIG. 2 is a diagram showing a head unit and an electron gun according to an embodiment. [Figure 3C] FIG. 2 is an enlarged view of a head portion according to an embodiment. [Figure 4A]FIG. 13 is a diagram showing an anode connection ring at the lower stage of a ceramic insulating tube according to one embodiment. [Figure 4B] 1 is a diagram showing a joining structure of a lower section of a ceramic insulating tube according to an embodiment of the present invention; [Diagram 5] FIG. 2 is a diagram showing a detailed configuration of an electron gun according to an embodiment. [Figure 6] FIG. 2 illustrates an anode and target according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0030] FIG. 1 is a diagram showing a microfocus X-ray tube according to an embodiment.

[0031] Referring to FIG. 1, the microfocus X-ray tube 100 is composed of an anode 150 , a head portion 160 and a ceramic insulating tube 180 .

[0032] In detail, the head unit 160 is made of a metal material, and a sheet-shaped window 161 may be bonded to one side of the head unit 160. For example, the sheet may be a thin plate. Here, the head unit 160 may be bonded together with a ring-shaped sheet cover 162 in order to increase the brazing bonding yield of the head unit 160 with the window 161. The head unit 160 is bonded to the electron gun 110 having the nano field emitter 123 on a side of the head unit 160. Here, the window 161 serves to emit the X-rays 200 generated by the electron beam 111 emitted from the electron gun 110 to the outside of the microfocus X-ray tube 100.

[0033] The ceramic insulating tube 180 may be bonded to the other surface of the head unit 160 at high temperature. The ceramic insulating tube 180 is bonded to the anode 150 via the anode connection ring 152. The ceramic insulating tube 180 forming the microfocus X-ray tube 100 is aligned by an insulating tube guide formed on the anode connection ring 152. The inner diameter of the ceramic insulating tube 180 and the outer diameter of the anode connection ring 152 may be separated from each other in consideration of the difference in thermal expansion coefficient, processing error, etc., and the distance between them may be 0.2 mm or less based on the radius. Here, the anode 150 may be disposed in the center of an internal space formed by the head unit 160 and the ceramic insulating tube 180 bonded at high temperature.

[0034] The anode 150 may be realized in a bottleneck structure in which the width of the anode 150 is narrowed at a certain point in order to ensure a withstand voltage. The anode 150 may be spaced apart from the ceramic insulating tube 180 in the internal space at a certain distance. A plate-shaped target 151 is disposed on the head of the anode 150. The head of the anode 150 may be formed to be inclined at a certain angle. The target 151 may be disposed by being brazed according to the certain angle of the head of the anode 150.

[0035] In addition, the electron beam 111 emitted from the electron gun 110 is accelerated by the voltage applied to the anode 150, and the X-rays 200 generated from the electron beam 111 that reaches the target 151 can be emitted outside the microfocus X-ray tube 100 through the window 161 of the head unit 160.

[0036] 2A to 2D are diagrams showing a joint structure of a microfocus X-ray tube according to an embodiment.

[0037] 2A to 2D, the microfocus X-ray tube 100 is manufactured as a vacuum sealed tube by brazing each component in a vacuum atmosphere without installing a separate exhaust tube for vacuum evacuation. Also, in order to minimize stress caused by the difference in thermal expansion coefficient between the ceramic insulating tube 180 and the metal head part 160, each joint may have a unique joint structure.

[0038] In detail, the microfocus X-ray tube 100 may have a structure in which dissimilar materials are bonded at high temperature, that is, the ceramic material of the ceramic insulating tube 180 and the metal material of the head unit 160. The microfocus X-ray tube 100 has a structure in which a large aperture is formed on a side surface of the head unit 160, and the electron gun 120 is bonded through the large aperture formed on the side surface.

[0039] Furthermore, the microfocus X-ray tube 100 may have a structure in which a high-voltage positive anode is disposed inside the microfocus X-ray tube 100, and a grounded negative cathode 120 and a window 161 are disposed on the side and top surfaces of the head unit 160. In the case of bipolar power supply drive, a positive voltage may be applied to the anode, and a negative voltage may be applied to the window 161 and the cathode.

[0040] Therefore, the present invention can provide an improved microfocus X-ray tube 100 by utilizing a direct vacuum brazing method without an exhaust tube in a ceramic insulating structure to manufacture a nano field emitter-based X-ray tube with excellent characteristics.

[0041] 3A to 3C are diagrams showing a head unit and an electron gun according to an embodiment.

[0042] 3A to 3C, the head unit 160 has an electron gun 110 having a nano field emitter disposed on a side of the head unit 160. An electron gun joint ring 169 of the head unit 160 may be brazed-joined to an insulating ceramic tube 141 of the electron gun 110. The electron gun 110 may be aligned to the head unit 160 by an electron gun alignment guide 170 formed on the head unit 160. The electron gun 110 includes a cathode electrode 120 connected to an external power supply (not shown), a gate electrode 130, and a focus electrode 140. The cathode electrode 120, the gate electrode 130, and the focus electrode 140 may be insulated and joined by insulating ceramic tubes 121, 131, and 141, respectively. The electron gun 110 will be described in more detail with reference to FIG. 5.

[0043] The head unit 160 may have a window 161 grounded on one surface thereof. The head unit 160 may further include a diffusion prevention groove 166 and a ring cover 162 associated with the window 161. The window 161 may emit the electron beam emitted from the electron gun 110 to the outside. For example, the window 161 may be made of beryllium or a thin metal having a thickness of 50 um or less, for example, copper.

[0044] The head portion 160 is formed with diffusion prevention grooves 166 for minimizing brazing material when the head portion 160 and the window 161 are grounded. The diffusion prevention grooves 166 are a long row of ring-shaped recesses recessed into the head portion 160. The diffusion prevention grooves 166 may be formed in the head portion 160 with at least one different diameter. The ring cover 162 is disposed on the head portion 160 along the diffusion prevention grooves 166.

[0045] The diffusion prevention groove 166 and the ring cover 162 can adjust the degree of diffusion of the brazing material onto the bonding surface, thereby increasing the bonding yield.

[0046] When the head portion 160 is joined to the ceramic insulating tube 180, it may be brazed to an insulating tube joint ring 167 formed on the head portion 160. The head portion 160 and the ceramic insulating tube 180 are aligned by an insulating tube alignment guide 168. The head portion 160 is formed with an insertion tube structure 164 including a recessed groove 163. The inner diameter of the ceramic insulating tube 180 and the outer diameter of the head portion 160 may be spaced apart in consideration of the difference in thermal expansion coefficient, processing error, etc., and the distance may be 0.2 mm or less based on the radius.

[0047] In addition, the thickness and length of the electron gun joining ring 169 of the head part 160 where different materials are joined and the insulating tube joining ring 167 of the head part 160 may be 0.5 mm and 1.5 mm.

[0048] The insertion tube structure 164 is inserted into the ceramic insulating tube 180 and is spaced apart from the ceramic insulating tube 180 by the recess 163. As an example, the insertion tube structure 164 may have a recess 163 in which a strip-shaped non-volatile getter (not shown) may be mounted.

[0049] A space 165 may be formed between the head portion 160 and the ceramic insulating tube 180 by the recessed groove 163. As an example, the head portion 160 may have an insertion tube structure 164 that is inserted into the ceramic insulating tube 180, and the space 165 that does not reach the ceramic insulating tube 180 may be formed by an insulating tube alignment guide 168.

[0050] 4A and 4B are diagrams showing an anode, a ceramic insulating tube, and an anode connecting ring according to one embodiment.

[0051] 4A-4B, a joint structure between the anode 150, the ceramic insulating tube 180, and the anode connection ring 152 is shown. In detail, the anode 150 may be made of a material such as copper having excellent thermal conductivity. The anode 150 may use the anode connection ring 152 made of a material such as Kovar to overcome the difference in thermal expansion coefficient.

[0052] The joints between the anode 150 and the ceramic insulating tube 180 can be minimized by utilizing the anode connecting ring 152 having thin joint ring structures 153, 156, and 157 to minimize stress due to differences in thermal expansion coefficients.

[0053] The anode 150 and the anode connection ring 152 are brazed at a joint 155 , and the ceramic insulation tube 180 can be joined by a joint ring structure 153 of the anode connection ring 152 and aligned by an insulation tube guide 154 .

[0054] FIG. 5 is a diagram showing a detailed configuration of an electron gun according to an embodiment.

[0055] 5, the electron gun 110 includes a cathode plate 122 having nano field emitters 123 formed thereon, a gate plate 132, and a focus plate 142. Here, the cathode plate 122 is coupled to a cathode electrode, the gate plate 132 is coupled to a gate electrode 130, and the focus plate 142 is coupled to a focus electrode.

[0056] Additionally, the gate plate 132 may be formed with a gate opening 133 to extract electrons from the nano field emitter 123. The focus plate 142 may be formed with a focus opening 143 to accelerate the electrons and focus the emitted electron beam 111.

[0057] The cathode plate 122, the gate plate 132, and the focus plate 142 are electrically connected and joined to the cathode electrode 120, the gate electrode 130, and the focus electrode 140, respectively, and the cathode electrode 120, the gate electrode 130, the focus electrode 140, and the head portion 160 may be insulated and joined by each insulating ceramic tube 121, 131, 141.

[0058] Each of the three electrodes can be connected to an external power supply. The size of the nano field emitter 123, as well as the distances between the cathode plate 122, the gate plate 132, the focus plate 142, and the head portion 160, and the sizes of the gate aperture 133, the focus aperture 143, and the head portion aperture 171 can be optimized for optimal focusing of the electron beam 111.

[0059] FIG. 6 is a diagram illustrating an anode and a target according to one embodiment.

[0060] 6, the anode 150 and the plate-shaped target 151 may be bonded together in various ways. Here, when the anode 150 is bonded together using a brazing material, a recess 163 may be formed in the anode 150 so that the bonding area is smaller than the area of ​​the target in order to prevent the filler from overflowing.

[0061] Meanwhile, the method according to the present invention may be implemented in various recording media such as a magnetic storage medium, an optically readable medium, and a digital storage medium, by being written as a program that can be executed by a computer.

[0062] Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations thereof. Implementations may be implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., a machine-readable storage device or a radio signal, for processing by or controlling the operation of a data processing device, e.g., a programmable processor, a computer, or a number of computers. Computer programs, such as those described above, may be stored in any form of programming language, including compiled or interleaved languages, and may be deployed in any form, including as a stand-alone program or as modules, components, subroutines, or other units suitable for use in a computing environment. Computer programs may be deployed to be processed on one computer or multiple computers at one site, or distributed across multiple sites and interconnected by a communications network.

[0063] Processors suitable for processing a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Typically, a processor will receive instructions and data from a read-only memory or a random access memory, or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will include one or more mass storage devices, such as magnetic, magneto-optical, or optical disks, for storing data, and may be coupled to receive data from, transmit data to, or both. Suitable information carriers for embodying computer program instructions and data include, by way of example, semiconductor memory devices, magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as compact disk read only memories (CD-ROMs) and digital video disks (DVDs), magneto-optical media such as floptical disks, read only memories (ROMs), random access memories (RAMs), flash memories, erasable programmable ROMs (EPROMs), electrically erasable programmable ROMs (EEPROMs), etc. The processor and memory may be supplemented by or included in special purpose logic circuitry.

[0064] Furthermore, the computer-readable recording medium may be any available medium that can be accessed by a computer and may include all of computer storage media and transmission media.

[0065] Although the specification includes details of several specific embodiments, these should not be construed as limitations on the scope of any invention or claimable therewith, but rather as descriptions of features that are specific to certain embodiments of a particular invention. Certain features described herein in the context of a separate embodiment may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented in multiple embodiments individually or in any suitable subcombination. Furthermore, although features may be described as operating in a particular combination and claimed therewith initially, one or more features from a claimed combination may, in some cases, be excluded from that combination, and the claimed combination may be modified into a subcombination or a variation of the subcombination.

[0066] Similarly, although acts are depicted in the figures in a particular order, this should not be construed as requiring such acts to be performed in the particular order shown, or in the sequential order shown, to obtain preferred results, or that all of the shown acts must be performed. In certain cases, multitasking and parallel processing may be advantageous. Also, the separation of various apparatus components in the above-described embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the program components and apparatus described are typically integrated together in a single software product or packaged in multiple software products.

[0067] Meanwhile, the embodiments of the present invention disclosed in this specification and the drawings are merely specific examples presented to aid in understanding, and are not intended to limit the scope of the present invention. It is obvious to a person having ordinary skill in the art to which the present invention pertains that other modifications based on the technical concept of the present invention can be implemented in addition to the embodiments disclosed in this specification. [Explanation of symbols]

[0068] 100: Microfocus X-ray tube 110: Electron gun 111: Electron beam 120: Cathode 130: Gate 140: Focus 150: Anode 151: Target 152: Anode connecting ring 160: Head section 161: Window 162: Lindpke 163: Intaglio groove 164: Insertion tube 180: Ceramic insulating tube 200:X-ray

Claims

1. 1. A microfocus X-ray tube, comprising: A metal head part, a ceramic insulating tube bonded to one surface of the head portion at high temperature; an electron gun having a nano field emitter bonded to a side of the head; an anode provided in an internal space formed by the head portion and the ceramic insulating tube which are joined at high temperature; A plate-shaped target attached to the anode; Including, The electron gun includes: a cathode plate and a gate plate on which the nano field emitters are formed; The cathode plate and the gate plate are electrically connected to a cathode electrode and a gate electrode, respectively; The cathode electrode, the gate electrode, and the head portion are insulated and joined by insulating ceramic tubes, The head portion is a window for emitting X-rays generated by the electron beam emitted from the electron gun to the outside; a diffusion prevention groove for minimizing brazing material during a process of joining the head portion and the window; A ring cover disposed along the diffusion prevention groove; A microfocus X-ray tube comprising:

2. The head portion is Sheet-like window and grounded, 2. The microfocus X-ray tube according to claim 1, wherein said sheet-like window allows X-rays generated by the electron beam emitted from said electron gun to be emitted outside the microfocus X-ray tube.

3. The head portion is formed in an insertion tube structure having a recessed groove on one surface of the head portion, 2. The microfocus X-ray tube according to claim 1, wherein the insertion tube structure is inserted into the ceramic insulating tube and spaced apart from the ceramic insulating tube by an insulating tube alignment guide.

4. the head portion is joined to an insulating ceramic of the electron gun via a joining ring of the electron gun; 2. The microfocus X-ray tube according to claim 1, wherein the position of the electron gun is aligned by an electron gun guide formed on a side surface of the head portion.

5. The ceramic insulating tube is It is connected to the anode via the anode connecting ring, 2. The microfocus X-ray tube according to claim 1, wherein the position of said ceramic insulating tube is aligned by an insulating tube guide formed on said anode connection ring.

6. The electron gun includes: The focus electrode is electrically connected to the focus plate, 2. The microfocus X-ray tube according to claim 1, wherein said focus electrode is joined to said cathode electrode, said gate electrode and said head portion while being insulated by said respective insulating ceramic tubes.

7. the gate plate has a gate opening formed therein for extracting electrons from the nano field emitter; 7. The microfocus X-ray tube according to claim 6, wherein said focus plate is formed with a focus aperture for focusing an electron beam emitted by accelerating said electrons.

8. the target is joined to the anode by a vacuum brazing material; 2. The microfocus X-ray tube according to claim 1, wherein said anode is formed with a recess so that a bonding area thereon is smaller than an area of ​​said target.

9. 1. A microfocus X-ray tube, comprising: a head portion joined to an electron gun having a nano-field emitter; a ceramic insulating tube bonded to the head portion at high temperature; an anode joined to the ceramic insulating tube and having a plate-shaped target attached thereto; Including, The electron gun includes: a cathode plate and a gate plate on which the nano field emitters are formed; The cathode plate and the gate plate are electrically connected to a cathode electrode and a gate electrode, respectively; The cathode electrode, the gate electrode, and the head portion are insulated and joined by insulating ceramic tubes, The head portion is a window for emitting X-rays generated by the electron beam emitted from the electron gun to the outside; a diffusion prevention groove for minimizing brazing material during a process of joining the head portion and the window; A ring cover disposed along the diffusion prevention groove; A microfocus X-ray tube comprising:

10. 10. The microfocus X-ray tube according to claim 9, wherein the head portion has an insertion tube structure in which a portion of the head portion is inserted into the ceramic insulating tube.

11. The head portion is The side surface of the head portion is joined to the insulating ceramic of the electron gun via a joining ring of the electron gun, 10. The microfocus X-ray tube according to claim 9, wherein the position of the electron gun is aligned by an electron gun guide formed on a side surface of the head portion.

12. The ceramic insulating tube is It is connected to the anode via the anode connecting ring, 10. The microfocus X-ray tube according to claim 9, wherein the position of the ceramic insulating tube is aligned by an insulating tube guide formed on the anode connection ring.

13. The electron gun includes: The focus electrode is electrically connected to the focus plate, 10. The microfocus X-ray tube according to claim 9, wherein the focus electrode is joined to the cathode electrode, the gate electrode, and the head portion while being insulated by the respective insulating ceramic tubes.

14. the gate plate has a gate opening formed therein for extracting electrons from the nano field emitter; 14. The microfocus X-ray tube according to claim 13, wherein the focus plate is formed with a focus aperture for focusing the electron beam emitted by accelerating the electrons.

15. 10. The microfocus X-ray tube according to claim 9, wherein the target is attached to the anode by a recess formed so that the bonding area of ​​the recess is smaller than the area of ​​the target.

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