Field emission x-ray source device

Abstract

To provide a field emission X-ray source device.SOLUTION: A field emission X-ray source device comprises: an insulating housing extending in a tube shape; an anode electrode covering one side of the insulating housing; a cathode electrode placed at the other side of the insulating housing and facing the anode electrode; a gate electrode covering the other side of the insulating housing and having an opening formed in the direction of the other side; an electronic emitter provided on the cathode electrode and configured to emit an electron beam toward the anode electrode; and a target which is provided on the anode electrode and placed to face the electronic emitter, and enables X-rays to be generated by collision with the electron beam.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a field emission X-ray source device, and more particularly to a field emission X-ray source device that collides electrons emitted from an electron emission source on the cathode electrode side with a target on the anode electrode side to emit X-rays.

Background Art

[0002] Conventional X-ray source devices use a hot cathode made of a tungsten material as an electron emission source for generating X-rays. A high voltage is applied to heat a tungsten filament to emit electrons, and the emitted electrons are collided with a target on the anode electrode side to generate X-rays.

[0003] However, in a tungsten filament-based hot cathode X-ray source device, there is a large amount of heat loss and a lot of power is consumed for generating electrons. Since the generated electrons are randomly emitted from the surface of tungsten having a spiral structure, the X-ray emission efficiency is extremely low. In addition, an interval of a certain time is required for heating and cooling the tungsten filament, and it is difficult to emit X-rays in a pulsed manner, so there are limitations in use.

[0004] In order to solve the problems of such conventional hot cathode X-ray source devices, in recent years, extensive research has been conducted on field emission X-ray source devices using nanostructures such as carbon nanotubes (CNTs) as cold cathode electron emission sources. Different from conventional tungsten filament-based hot cathode X-ray source devices, the field emission X-ray source device has an electron emission mechanism based on the field emission method. The field emission X-ray source device has lower power consumption compared to a tungsten filament-based hot cathode X-ray source device, and since the emitted electrons are emitted along the longitudinal direction of nanostructures such as carbon nanotubes, it has excellent directionality of electrons toward the target on the anode electrode side and very high X-ray emission efficiency. In addition, it is easy to emit pulsed X-rays through field control.

[0005] The conventional field emission X-ray source device 9 shown in FIG. 1 includes a housing 91 made of an insulating material, an anode electrode 92 covering one side of the housing 91, a cathode electrode 93 covering the other side of the housing, and a gate electrode 94 disposed at a predetermined distance from the cathode electrode on one side of the cathode electrode.

[0006] A conventional field emission X-ray source includes an electron emitter provided on a cathode electrode and a gate electrode provided adjacent thereto within an insulating housing. Electrons are emitted from the electron emitter by an electric field formed between the gate electrode and the cathode electrode. The gate electrode has a mesh shape or a metal plate shape in which a number of holes are arranged according to the arrangement of the electron emitters. When an electron beam emitted from the electron emitter passes through such a mesh structure or a number of holes and travels, the electrons are accelerated by a potential difference of several tens to several hundreds of kV formed between the anode electrode and the cathode electrode, and are made to strike an X-ray target provided on the anode electrode side to emit X-rays. On the other hand, one or more focusing electrodes may be added between the anode electrode 92 and the gate electrode 94 so that the electron beam is focused on a region of the anode electrode. To operate the field emission X-ray source device, a positive gate voltage with a difference of more than ten kV and a positive acceleration voltage with a difference of several tens to several hundreds of kV are applied to the gate electrode and the anode electrode, respectively, with reference to the potential of the cathode electrode. At this time, a voltage for focusing the electron beam is applied to the focusing electrode, and the voltage applied to the focusing electrode can be changed according to the operating conditions.

[0007] In a field emission X-ray source device having such a structure, since a high potential difference is applied to the anode electrode 92, the cathode electrode 93, and the gate electrode 94, insulation is important. In the case of such a field emission X-ray source device, a predetermined insulation distance is ensured. However, in the case of the gate electrode 94 formed of a conductive material, it is vulnerable to high voltages and there is a risk of dielectric breakdown. Near the target provided on the anode electrode, the insulating housing may be damaged or the durability may be reduced by the high voltage. In addition, there is a risk that the gate electrode 94 is exposed between the anode electrode 92 and the cathode electrode 93, resulting in a reduction in insulation performance.

[0008] Accordingly, there is a need for a field emission X-ray source device that can increase the insulation distance between the gate electrode and the anode electrode compared to a conventional field emission X-ray source device, is easy to manufacture, and minimizes the exposure of the cathode electrode.

[0009] The technology that is the background of the present invention is disclosed in Patent Document 1.

Prior Art Document

Patent Document

[0010]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0011] The present invention is for solving the above-described problems of the prior art, and an object thereof is to provide a field emission X-ray source device in which the insulation distance between the gate electrode and the anode electrode is increased compared to a conventional field emission X-ray source device.

[0012] Another object of the present invention is to provide a field emission X-ray source device in which the cathode electrode and the gate electrode are modularized and easy to manufacture.

[0013] Another object of the present invention is to provide a field emission X-ray source device that minimizes the exposure of the cathode electrode to the outside of the insulating housing.

[0014] However, the technical problems to be solved by the embodiments of the present invention are not limited to the above-described technical problems, and other technical problems may exist.

Means for Solving the Problems

[0015] As a technical means for achieving the above object, a field emission X-ray source device according to an embodiment of the present invention includes a tubular insulating housing, an anode electrode covering one side of the insulating housing, a gate electrode covering the other side of the insulating housing, a cathode electrode disposed on the other side inside the insulating housing, an electron emission source provided on the cathode electrode and emitting an electron beam toward the anode electrode, and a target provided on the anode electrode, facing the electron emission source, and generating X-rays by the collision of the electron beam.

[0016] According to an embodiment of the present invention, the gate electrode may include a first gate portion covering the other side of the insulating housing, a cylindrical second gate portion mounted on the first gate portion inside the insulating housing, and a gate mesh provided on the second gate portion.

[0017] According to an embodiment of the present invention, the device may further include a cylindrical insulating spacer mounted on the first gate portion inside the second gate portion. The cathode electrode is mounted on the insulating spacer inside the second gate portion, and the electron emission source and the gate mesh can face each other.

[0018] According to an embodiment of the present invention, the device may further include an opening provided in the first gate portion inside the second gate portion and exposing the cathode electrode to the outside.

[0019] Further, according to an embodiment of the present invention, the second gate portion may further include a gate flange extending to one side of the gate mesh.

[0020] Further, according to an embodiment of the present invention, the gate electrode, the cathode electrode, and the insulating spacer can be modularized and coupled to the insulating housing.

[0021] Further, according to an embodiment of the present invention, the anode electrode may include an anode hood that surrounds the target and extends to the other side of the portion where the target is disposed.

[0022] Further, according to an embodiment of the present invention, a window provided in the anode hood and transmitting X-rays generated from the target can be further provided.

[0023] The above means for solving the problems are merely exemplary and should not be construed as intending to limit the present invention. In addition to the above-described exemplary embodiments, there may be additional embodiments in the drawings and the detailed description of the invention.

Effect of the Invention

[0024] According to the means for solving the problems of the present invention described above, the present invention has an effect of providing a field emission X-ray source device in which the insulation distance between the gate electrode and the anode electrode is increased as compared with a conventional field emission X-ray source device.

[0025] Further, the present invention can provide a field emission X-ray source device in which the cathode electrode and the gate electrode are modularized and easy to manufacture.

[0026] Further, the present invention has an effect of minimizing the exposure of the cathode electrode to the outside of the insulating housing.

[0027] However, the effects achieved by the embodiments of the present invention are not limited to the above-described effects, and other effects may exist.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0029] Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention pertains can easily implement it. However, the present invention can be realized in various different forms and is not limited to the embodiments described here. And, in the drawings, parts not related to the explanation are omitted for clearly explaining the present invention, and similar reference numerals are given to similar parts throughout the specification.

[0030] Throughout this specification, when a certain part is said to be "connected" to another part, this includes not only the case where it is "directly connected", but also the case where it is "indirectly connected" with another configuration interposed therebetween or the case where it is "electrically connected" with another element interposed therebetween.

[0031] Throughout this specification, when a certain member is said to be located "above", "upper part", "upper end", "below", "lower part", "lower end" of another member, this includes not only the case where a certain member is in contact with another member, but also the case where another member is interposed between the two members.

[0032] Throughout this specification, when a part states that a certain component "includes" something, this means that, unless otherwise stated to the contrary, it does not exclude other components, but may further include other components.

[0033] Terms such as "first" and "second" can be used to represent the same or substantially the same configuration with different orders, and can be interpreted as being substantially the same as the configuration not indicated by "first", "second", etc.

[0034] Also, among the descriptions of the embodiments of the present invention, terms related to directions and positions (such as upper side, upper surface, lower side, etc.) are set based on the arrangement state of each component shown in the drawings.

[0035] In an embodiment of the present invention, the upper side or the upper surface can be understood as the direction in which the anode electrode 20 is arranged with respect to the insulating housing 10 (the 12 o'clock direction in FIGS. 2 and 3), and the lower side or the lower surface can be understood as the direction in which the cathode electrode 60 is arranged with respect to the insulating housing 10 (the 6 o'clock direction in FIGS. 2 and 3).

[0036] Hereinafter, the field emission X-ray source device 1 according to a preferred embodiment of the present invention will be described. Referring to FIGS. 2 to 4, the field emission X-ray source device 1 can include an insulating housing 10, an anode electrode 20, a target 30, a gate electrode 40, an insulating spacer 50, a cathode electrode 60, and an electron emission source 70.

[0037] The insulating housing 10 can be formed of an insulating material such as ceramic, glass, or silicone, and can be made of a material such as alumina ceramics, for example. Since the insulating housing 10 is made of an insulating material, the field emission X-ray source device 1 can electrically insulate the anode electrode 20 and the cathode electrode 60 from each other. Further, the inside of the insulating housing 10 can be maintained in a vacuum state or a sub-vacuum state close to this.

[0038] The insulating housing 10 can extend in a tubular shape with one side and the other side covered by the anode electrode 20 and the gate electrode 40, which will be described later. That is, the insulating housing 10 can have a tubular shape with one side and the other side, i.e., the upper surface and the other surface, open, and as will be described later, one side can be covered by the anode electrode 20 and the other side can be covered by the gate electrode 40. The insulating housing 10 can be an integrally extended tube.

[0039] Also, a portion on one side of the insulating housing 10, specifically, a portion where X-rays are emitted near the anode electrode 20, can be formed to have a thickness thinner than other portions on the upper and lower sides, as shown in FIG. 3. Thereby, unnecessary wavelength bands can be filtered from the X-rays passing through the portion.

[0040] The anode electrode 20 can be arranged to cover one side of the insulating housing. The anode electrode 20 forms a high potential difference of several tens to several hundreds of kV with the cathode electrode 60 where the electron emission source 70, which will be described later, is arranged, serves as an accelerating electrode, and also serves as an X-ray target that emits X-rays by the collision of electrons emitted from the electron emission source 70 and accelerated. The anode electrode 20 can include an anode electrode body that covers the insulating housing, and can include a heat dissipation structure 21 outside the insulating housing and an anode hood 23 inside the insulating housing.

[0041] The anode electrode body can be formed of various conductive metal materials. As an example, it can be formed of oxygen-free copper (OFHC). Among metal materials that can withstand high temperatures, those with a higher thermal conductivity than the target 30 are advantageous from the perspective of heat diffusion, and it can be understood that those with a thermal expansion coefficient similar to that of the insulating housing 10 are advantageous from the perspective of the bonding property with the insulating housing 10.

[0042] The heat dissipation structure 21 can be provided on a part exposed on one side of the insulating housing 10 so as to increase the surface area of the anode electrode. As an example, the heat dissipation structure 21 can be composed of a plurality of heat dissipation fins extending from the anode electrode body, but is not limited thereto.

[0043] The anode hood 23 can have a cylindrical shape that surrounds the target and extends to the other side from the portion where the target is disposed. That is, the anode hood 23 extends downward from the target while surrounding the target, and can prevent scattering of X-rays generated from the target 30.

[0044] The side surface of the anode hood 23 can have a window 23a that transmits X-rays generated from the target 30. The window 23a can be made of any one of beryllium (Be), aluminum (Al), magnesium (Mg), aluminum nitride (AlN), aluminum-beryllium alloy (AlBe), silicon oxide (SixOy), and titanium (Ti), or an alloy thereof, which have a relatively high X-ray transmittance. In a preferred embodiment, the window is formed of a beryllium material and can filter unnecessary wavelength bands in the X-rays.

[0045] The target 30 is subjected to the impact of the electron beam E emitted from the electron emission source 70, and can provide a target surface inclined with respect to the traveling direction of the electron beam E. The target 30 can be surrounded by the anode hood 23. The target 30 can be made of tungsten (W), copper (Cu), molybdenum (Mo), cobalt (Co), chromium (Cr), iron (Fe), silver (Ag), tantalum (Ta), yttrium (Y), etc., which emit X-rays by the impact of the accelerated electron beam E.

[0046] The target 30 emits X-rays when struck by accelerated electrons. However, when continuously struck by the electron beam E, the focal point on the target 30 reaches a high temperature of about 2700 °C or higher, and the entire anode electrode 20 reaches about 1700 °C. Even at such a high temperature, as an example, the target 30 can be formed of tungsten (W) with a high melting point of 3440 °C in order to prevent focal spot fluctuations due to deformation.

[0047] The gate electrode 40 can cover the other side of the insulating housing and can have an opening 41a formed on one side thereof, for example, in the other side direction. As will be described later, the cathode electrode 60 is mounted on the gate electrode 40 in the insulating housing via the insulating spacer 50 and can communicate with the outside of the insulating housing 10 through the opening 41a. A part of the gate electrode 40 is disposed between the electron emission source 70 and the anode electrode 20 to be described later and can form an electric field for starting electron emission.

[0048] In one embodiment, the gate electrode 40 can be formed of the same material as the anode electrode 20, but is not limited thereto. As an example, a part of the gate electrode 40 can be formed of the same material as the anode electrode 20, and the other part can be formed of an iron-nickel-cobalt alloy called Kovar. Specifically, the part forming the gate flange 433 is formed of an iron-nickel-cobalt alloy called Kovar, and the other parts of the gate electrode excluding this, for example, the first gate part 41 and the gate body 431, can be formed of oxygen-free copper.

[0049] The gate electrode 40 can include a first gate part 41 that covers the other side of the insulating housing 10 and a second gate part 43 that is disposed in the space formed by the insulating housing and the first gate part.

[0050] The first gate portion 41 can be formed to cover the lower side surface and the lower surface of the insulating housing 10. That is, it can be understood that the first gate portion 41 covers the other side of the insulating housing 10 and is exposed to the outside. The first gate portion 41 can have an opening 41a formed in the downward direction. A gate voltage, that is, a voltage for inducing electron emission from the electron emission source, can be applied through the first gate portion 41.

[0051] Referring to the conventional field emission X-ray source device in which the gate electrode 94 shown in FIG. 1 is disposed between the cathode electrode 93 and the anode electrode 92, the insulating housing 91 is separated vertically by the gate electrode 94, and the insulation distance between the anode electrode 92 and the gate electrode 94 is limited to the vertical distance between the anode electrode 92 and the gate electrode 94.

[0052] When comparing with the conventional field emission X-ray source device 9, the gate electrode 40 of the present invention is provided such that the first gate portion 41 covers the lower side of the insulating housing 10, so that the upper end of the gate electrode 40 can move downward compared to the conventional gate electrode. As a result, the insulation distance between the upper end of the gate electrode 40 and the anode electrode 20 can be increased. In addition, since the insulating housing 10 is integrally formed without being separated vertically by the gate electrode 40, a phenomenon that causes a decrease in durability such as ceramic puncture that may occur at the joint portion can be minimized.

[0053] The second gate portion 43 can be mounted on the first gate portion inside the insulating housing. The second gate portion 43 can play a role of substantially forming an electric field inside the space formed by the insulating housing and the first gate portion. The second gate portion 43 can include a gate body 431, a gate mesh 432, and a gate flange 433.

[0054] The gate body 431 is mounted on the first gate portion 41 and can extend upward from the first gate portion 41. The gate body 431 has a cylindrical shape and is provided to accommodate and surround the insulating spacer 50 therein.

[0055] The gate mesh 432 can be disposed within the second gate portion 43. The electron beam emitted from the electron emission source 70 can pass through the gate mesh 432 and proceed. The gate mesh 432 can be a thin metal plate in which a number of holes are formed so that the electron beam can pass through, or can be provided in the form of a metal mesh. The gate mesh 432 can have a circular cross-section so as to be mounted on a mesh opening having a circular cross-section formed on one side of the cathode electrode.

[0056] Also, the gate mesh 432 can be disposed at a distance from the electron emission source 70 toward the anode electrode 20 side. That is, the electron emission source 70 at the upper end of the cathode electrode 60 and the gate mesh 432 can be disposed to face each other with a certain distance therebetween. For example, the gate mesh 432 can be disposed at a distance of 0.1 mm from the electron emission source 70, but is not limited thereto.

[0057] The gate flange 433 can perform focusing for the concentration of the electron beam passing through the gate mesh 432. The gate flange 433 can surround the gate mesh 432 and can extend to one side from the portion where the gate mesh is disposed. That is, the gate flange 433 can extend above the gate mesh 432 while surrounding the gate mesh.

[0058] The gate flange 433 can form a hollow 433a through which the electron beam passes through the gate mesh 432 and proceeds. The hollow 433a can have a cross-section of a predetermined shape extending in the vertical direction, but the cross-sectional shape of the hollow 433a can vary depending on the voltage applied to the anode electrode 20 and the cathode electrode 60 and the target X-ray emission amount. That is, it can be understood that the shape of the gate flange 433 is determined to be different by the X-ray emission due to the focusing of the electron beam.

[0059] In a preferred embodiment, when the tilt angle of the target (compared to the horizontal line in FIG. 3) is 25 degrees, the hollow formed by the gate flange can have a square cross-section. At this time, the square cross-section can be understood as a square or rectangular cross-section. Also, as shown in FIG. 5, it is preferably understood as a concept including a shape in which the four corners of the square cross-section are chamfered (fillet).

[0060] The insulating spacer 50 can be disposed inside the second gate portion 43 on the first gate portion 41. The insulating spacer 50 can have a cylindrical shape made of an insulating material. As an example, the insulating spacer 50 can be the same as or made of a material with similar thermal behavior to the insulating housing 10.

[0061] The cathode electrode 60 can be mounted on the insulating spacer 50 extending from the gate electrode 40 to one side inside the insulating housing 10. Also, the cathode electrode 60 can be provided to communicate with the outside of the insulating housing through the opening 41a formed in the first gate portion. The cathode electrode 60 is disposed inside the insulating housing so as to be insulated from the gate electrode 40 and is exposed to the outside through the opening 41a of the gate electrode 40, so that dielectric breakdown and arcing can be minimized. The cathode electrode 60 can be formed of substantially the same material as the gate electrode and the anode electrode, for example, oxygen-free copper.

[0062] The cathode electrode 60 can be disposed on the other side of the insulating housing and can face the anode electrode. Electrons can be emitted from the electron emission source 70 disposed on the cathode electrode 60 to induce the generation of X-rays.

[0063] The cathode electrode 60 can include a cathode electrode body 61 disposed on the insulating spacer 50, an extension portion 62 extending downward (the other side) from the cathode electrode body, and an extension portion 63 extending outside the insulating spacer through the insulating spacer. A mounting groove recessed upward in a ring shape can be formed between the extension portion 63 and the cathode electrode body 61 for mounting on the insulating spacer 50. In one embodiment, a voltage can be applied to the cathode electrode 60 through the end of the extension portion 62.

[0064] The electron emission source 70 can be disposed on the cathode electrode 60. The electron emission source 70 can be provided on a separate substrate, can be coupled to the cathode electrode 60, or can be directly formed on the surface of the cathode electrode 60. The electron emission source 70 can be, for example, one using a number of nanostructures such as carbon nanotubes. In the case of the electron emission source 70 using carbon nanotubes, a number of carbon nanotubes can be directly grown on the surface of the substrate or the cathode electrode 60 using chemical vapor deposition (CVD), or can be formed by a method such as applying a carbon nanotube paste and then firing.

[0065] In a preferred embodiment, the electron emission source can be a carbon nanotube, but instead of emitting electrons by a thermionic method, it can emit electrons by a current control method, so that the on / off of the field emission X-ray source device can be easily controlled through the gate voltage applied to the gate electrode 40, and a compact structure can be obtained.

[0066] Also, since the electron emission source 70 is made of a nanostructure such as a carbon nanotube, the heat generated from the cathode electrode 60 side can be minimized. Accordingly, the anode electrode 20 portion has a heat dissipation structure 21 that increases the surface area of the anode electrode at the portion exposed on one side of the insulating housing, while the cathode electrode 60 can be provided so as not to have a heat dissipation structure that increases the surface area of the cathode electrode at the portion exposed on one side of the insulating housing.

[0067] Referring again to FIGS. 2 and 3, in the field emission X-ray source device 1 according to an embodiment of the present invention, the anode electrode 20 is exposed on the upper side of the insulating housing 10, and the gate electrode 40 can be exposed on the lower side. The cathode electrode 60 can be mounted on the gate electrode 40 inside the insulating housing 10 via an insulating spacer 50 and can be provided to communicate with the outside through an opening formed in the gate electrode 40.

[0068] Also, the second gate portion 43 can surround the cathode electrode 60 mounted on the insulating spacer 50, and the first gate portion 41 can surround the second gate portion. The space between the first gate portion 41 and the second gate portion 43 is the internal space of the insulating housing 10 and can be understood to be substantially in a vacuum state, and the space between the gate body 431 of the second gate portion 43 and the insulating spacer 50 and the cathode electrode 60 inside it can also be understood to be substantially in a vacuum state.

[0069] Conventionally, the insulating housing has to be divided vertically by the gate electrode and used in multiple stages. However, in the case of the present invention, by modularizing the gate electrode, the cathode electrode, and the insulating spacer so that they can be combined with a single insulating housing 10, the cathode module including the gate electrode and the cathode electrode can be easily combined with the insulating housing, thereby improving the manufacturability.

[0070] The above description of the present invention is for illustrative purposes, and those with ordinary knowledge in the technical field to which the present invention pertains can understand that it can be easily deformed into other specific forms without changing the technical idea and essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all aspects and not restrictive. For example, each component described as a single type may be implemented dispersedly, and similarly, the components described as being dispersed may also be implemented in a combined form.

[0071] The scope of the present invention is indicated by the claims described later rather than the above detailed description, and all changes or modifications derived from the meaning, scope, and equivalent concept of the claims should be construed as being included in the scope of the present invention.

Explanation of Signs

[0072] 1 Field emission X-ray source device 10 Insulating housing 20 Anode electrode 21 Heat dissipation structure 23 Anode hood 30 Target 40 Gate electrode 41 First gate section 43 Second gate section 431 Gate body 432 Gate mesh 433 Gate flange 50 Insulating spacer 60 Cathode electrode 70 Electron emission source

Claims

1. An electric field emission X-ray source device, A tubular insulating housing, An anode electrode covering one side of the insulating housing, A gate electrode covering the other side of the insulating housing, A cathode electrode disposed on the other side inside the insulating housing, An electron emission source provided on the cathode electrode and emitting an electron beam toward the anode electrode, A target provided on the anode electrode, facing the electron emission source, and generating X-rays by the collision of the electron beam. An electric field emission X-ray source device comprising the above.

2. The gate electrode is A first gate portion covering the other side of the insulating housing, A cylindrical second gate portion mounted on the first gate portion inside the insulating housing, A gate mesh provided on the second gate portion. The electric field emission X-ray source device according to claim 1.

3. Further comprising a cylindrical insulating spacer mounted on the first gate portion inside the second gate portion, The cathode electrode is mounted on the insulating spacer inside the second gate portion, and the electron emission source and the gate mesh face each other. The electric field emission X-ray source device according to claim 2.

4. Further comprising an opening provided in the first gate portion inside the second gate portion and exposing the cathode electrode to the outside. The electric field emission X-ray source device according to claim 3.

5. The second gate portion further comprises a gate flange extending to one side of the gate mesh. The electric field emission X-ray source device according to claim 2.

6. The gate electrode, cathode electrode, and insulating spacer are modularized and coupled to the insulating housing. The electric field emission X-ray source device according to claim 4.

7. The field emission X-ray source device according to claim 1, wherein the anode electrode includes an anode hood that surrounds the target and extends to the other side from the portion where the target is disposed.

8. The field emission X-ray source device according to claim 7, further comprising a window provided in the anode hood and transmitting the X-ray generated from the target.

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