Micro-focus X-ray device

Abstract

The utility model relates to a micro-focus X-ray device, which belongs to the technical field of X-rays and solves the problem of low resolution of CT (computed tomography) images caused by oval effective focuses of X-rays generated in the prior art. The micro-focus X-ray device comprises an electron beam generator, a focusing assembly, a lens assembly and a target, the electron beam generator is used for emitting electron beams, and the focusing assembly, the lens assembly and the target are all arranged on one side of the emitting end of the electron beam generator and are sequentially arranged in the electron movement direction of the electron beams; the lens assembly comprises two electron optical lenses, the two electron optical lenses are sequentially arranged in the electron movement direction, polar plates of the two electron optical lenses are aligned in the electron movement direction, and the polarities of the two aligned polar plates are opposite. The effective focus of the micro-focus X-ray generated by the micro-focus X-ray device is closer to a circle, so that the resolution of a CT (computed tomography) image can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to X ray technical field especially relates to a kind of microfocus X ray device. BACKGROUND

[0002] Microfocus X ray device based on the principle that X ray is radiated from target by fine focusing electron beam bombardment is the key core component of industrial micro-CT, and the smaller its focal size is, the higher the resolution of CT image is;The closer to circularity its focal shape is, the less the geometric shadow of CT image is, and the more distinct the boundary is.Reflective closed tube microfocus X ray device is oval in its actual effective focal point due to the influence of its geometric structure, which will reduce the resolution of CT image and limit its application scenarios.In order to solve this problem, the influence of cathode structure and anode structure of X ray tube on focal spot is studied by experiment and simulation in prior art, for example, the influence of parameters such as grid voltage, filament assembly height, focusing groove width and set cover hole depth on focal spot is analyzed to guide the optimal design of geometric structure of reflective closed tube microfocus X ray device.However, according to practical situation, the shape of effective focal point of microfocus X ray tube with existing structure has not been well improved. SUMMARY

[0003] In view of the above analysis, the utility model aims at providing a kind of microfocus X ray device to solve the problem that the shape of effective focal point of X ray generated by existing microfocus X ray device is oval, which leads to low resolution of CT image.

[0004] The utility model provides a kind of microfocus X ray device, the microfocus X ray device includes: electron beam generator, focusing component, lens component and target,

[0005] The electron beam generator is used to emit electron beam, the focusing component, the lens component and the target are all arranged on the side of the emission end of the electron beam generator, and are sequentially arranged along the electron motion direction of the electron beam;

[0006] The lens component includes two electron optical lenses, two the electron optical lenses are sequentially arranged along the electron motion direction, and the pole plate of two the electron optical lenses is aligned along the electron motion direction, and the polarity of the aligned two pole plates is opposite;

[0007] Wherein, the electron beam emitted by the electron beam generator is bombarded on the target after sequentially passing through the focusing component and the lens component, to generate microfocus X ray.

[0008] Based on the further improvement of the microfocus X ray device as described above, the electron optical lens is electrostatic lens or magnetic lens.

[0009] Based on the further improvement of the microfocus X-ray device as described above, the electron optical lens has at least four pole plates, the pole plates include anode pole plates and cathode pole plates, the number of the anode pole plates is the same as that of the cathode pole plates, and the anode pole plates and the cathode pole plates are uniformly and alternately arranged around the central axis of the electron optical lens.

[0010] Based on the further improvement of the microfocus X-ray device as described above, the interval between the aligned two pole plates is 10mm to 20mm.

[0011] Based on the further improvement of the microfocus X-ray device as described above, the electron optical lens has at least four pole plates, the pole plates include anode pole plates and cathode pole plates, the number of the anode pole plates is the same as that of the cathode pole plates, and the anode pole plates and the cathode pole plates are uniformly and alternately arranged around the central axis of the electron optical lens.

[0012] Based on the further improvement of the microfocus X-ray device as described above, the shape of the pole plate is round stick, concave circle, plane or rod.

[0013] Based on the further improvement of the microfocus X-ray device as described above, the electron beam generator includes an emitter, a heating electrode, a base, a grid cover and a grid control electrode,

[0014] The heating electrode is arranged on the base; one end of the heating electrode is connected with the emitter to heat and promote the emitter to emit electrons; the grid cover is arranged on the outer periphery of the emitter, and a circular hole for leading out the electron beam is arranged on the grid cover; and the grid control electrode is connected on the outer wall of the grid cover to control the density of the electron beam.

[0015] Based on the further improvement of the microfocus X-ray device as described above, a separation ring is arranged between the grid cover and the emitter.

[0016] Based on the further improvement of the microfocus X-ray device as described above, the focusing assembly includes a first focusing cylinder, a second focusing cylinder, a first focusing electrode, a second focusing electrode and an insulating gasket,

[0017] The first focusing cylinder and the second focusing cylinder are connected through the insulating gasket, the center of the first focusing cylinder, the insulating gasket and the second focusing cylinder are all provided with a circular through hole extending in the axial direction, the first focusing electrode is connected on the outer wall of the first focusing cylinder, and the second focusing electrode is connected on the outer wall of the second focusing cylinder.

[0018] Based on the further improvement of the microfocus X-ray device as described above, the microfocus X-ray device further includes a heat dissipation base body, and the target is arranged on the heat dissipation base body.

[0019] Compared with the prior art, the microfocus X-ray device has at least one of the following advantages:

[0020] 1. The lens assembly composed of two electron optical lenses is adopted to assist focusing in the utility model, the pole plate of two electron optical lenses is aligned along the electron movement direction, and the polarity of the aligned two pole plates is opposite, so that the focusing effect on the uniform electron beam in multiple directions can be achieved, the image difference is better corrected, the quality of the electron beam is improved, the effective focus of the generated microfocus X-ray is closer to a circle, and then the resolution of the CT image is improved.

[0021] 2. The structure of the electron beam generator is improved in the utility model, the structure is simple, the electron beam with high brightness, high stability and fine control can be generated, the emitter can be protected and the path of the electron beam can be stabilized by arranging the grid cover, the electron beam can be led out through the circular hole on the grid cover, the size and shape of the electron beam can be adjusted by changing the size and shape of the circular hole on the grid cover, and the density of the electron beam can be accurately controlled by connecting the grid control electrode on the outer wall of the grid cover.

[0022] 3. The focusing assembly of the utility model has a simple structure, the focusing of the electron beam can be accurately controlled by changing the voltage difference between the first focusing electrode and the second focusing electrode and the corresponding focusing cylinder, meanwhile, the insulating gasket is used to ensure the electrical isolation between the first focusing cylinder and the second focusing cylinder and allow the electron beam to pass through the circular through hole thereon.

[0023] 4. In the utility model, the target is arranged on the heat dissipation base body, the large amount of heat generated by the target under the high-speed electron impact is managed, and the performance, reliability and service life of the microfocus X-ray device are improved.

[0024] In the utility model, the above technical solutions can be combined with each other to realize more preferred combination solutions. Other features and advantages of the utility model will be described in the following content, and some advantages can become apparent from the description or can be understood by implementing the utility model. The purpose and other advantages of the utility model can be realized and obtained through the content specially pointed out in the text and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0025] The drawings are only used for the purpose of showing the specific embodiments, and are not considered as limiting the utility model, and the same reference signs represent the same parts in the whole drawings.

[0026] Figure 1 It is a structure schematic view of the microfocus X-ray device of one embodiment of the utility model;

[0027] Figure 2 It is a structure schematic view of the electron beam generator and the focusing assembly of one embodiment of the utility model;

[0028] Figure 3 Figure 1 is a schematic diagram of the distribution position of the pole plate of an electron optical lens according to an embodiment of the present application.

[0029] Reference signs:

[0030] 1 - electron beam generator; 11 - emitter; 12 - heating electrode; 13 - base;

[0031] 14 - grid cover; 15 - grid control electrode;

[0032] 2 - focusing assembly; 21 - first focusing cylinder; 22 - second focusing cylinder; 23 - first focusing electrode;

[0033] 24 - second focusing electrode; 25 - insulating gasket;

[0034] 3 - lens assembly; 31 - anode pole plate; 32 - cathode pole plate;

[0035] 4 - target;

[0036] 5 - heat dissipation base body. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present application will be described in detail below with reference to the drawings, wherein the drawings constitute a part of this application and serve to explain the principles of the present application together with the embodiments of the present application, but are not intended to limit the scope of the present application.

[0038] One embodiment of the present application discloses a microfocus X-ray device, as shown in Figure 1 The microfocus X-ray device comprises an electron beam generator 1, a focusing assembly 2, a lens assembly 3 and a target 4, the electron beam generator 1 is used for emitting an electron beam, the focusing assembly 2, the lens assembly 3 and the target 4 are all arranged on one side of the emission end of the electron beam generator 1 and are arranged in sequence along the electron motion direction of the electron beam; the lens assembly 3 comprises two electron optical lenses, the two electron optical lenses are arranged in sequence along the electron motion direction, the pole plates of the two electron optical lenses are aligned along the electron motion direction, and the polarities of the two aligned pole plates are opposite.

[0039] The electron beam emitted by the electron beam generator 1 passes through the focusing assembly 2 and the lens assembly 3 in sequence and then hits the target 4, so as to generate a microfocus X-ray.

[0040] Compared with the prior art, in the embodiment, the two electron optical lenses are combined to form a lens assembly 3 to assist focusing, the pole plates of the two electron optical lenses are aligned along the electron movement direction, and the polarities of the two aligned pole plates are opposite, so that the focusing effect on the electron beams in multiple directions is uniform, the image difference is better corrected, the quality of the electron beams is improved, the effective focal point of the generated microfocus X-ray is closer to a circle, and the resolution of the CT image is improved.

[0041] Notably, in the utility model, considering that the effect of a single electron optical lens on the electron beam has only one converging direction and another diverging direction, the combination of two electron optical lenses is adopted to focus the electron beams in multiple directions.

[0042] Specifically, the electron optical lens is an electrostatic lens or a magnetic lens.

[0043] Specifically, the electron optical lens has at least four pole plates, the pole plates include anode pole plates 31 and cathode pole plates 32, the number of the anode pole plates 31 is the same as that of the cathode pole plates 32, and the anode pole plates 31 and the cathode pole plates 32 are alternately arranged uniformly around the central axis of the electron optical lens, as shown in the figure. Figure 3

[0044] Specifically, in the embodiment, the electron optical lens can be a four-pole lens, a six-pole lens or an eight-pole lens, and preferably an eight-pole lens. The more the number of pole plates is, the more uniform the distribution of the electric field or the magnetic field of the electron optical lens is, and the stronger the focusing ability is.

[0045] Specifically, the interval between the two aligned pole plates is 10 mm to 20 mm.

[0046] In implementation, the lens assembly 3 is composed of two eight-pole lenses. In installation, the two eight-pole lenses are placed in parallel at an interval of 15 mm, and then one of the eight-pole lenses is rotated clockwise or counterclockwise, so that the anode pole plate of the eight-pole lens is aligned with the cathode pole plate of the other eight-pole lens.

[0047] Specifically, in the electron optical lens, a separation strip is arranged between the two adjacent pole plates. The separation strip is used for insulating and separating the two adjacent pole plates, and can be made of ceramic material.

[0048] Specifically, the shape of the pole plate is a round stick, a concave circle, a plane or a rod, and preferably a concave circle. The shape of the pole plate of the electron optical lens is different, the direction of the magnetic field is different, and the effect of the electron beam is different. When the shape of the pole plate is a round stick, a concave circle, a plane or a rod, the electron optical lens can focus the electron beam. ​

[0049] In one specific embodiment, as shown in Figure 2 The electron beam generator 1 comprises an emitter 11, a heating electrode 12, a base 13, a grid cover 14 and a grid control electrode 15. The heating electrode 12 is arranged on the base 13; the heating electrode 12 is connected to one end of the emitter 11 to heat the emitter 11 to facilitate electron emission; the grid cover 14 is arranged on the outer periphery of the emitter 11, and the grid cover 14 is provided with a circular hole for leading out the electron beam; the grid control electrode 15 is connected to the outer wall of the grid cover 14 to control the density of the electron beam.

[0050] Compared with the prior art, the structure of the electron beam generator 1 is improved in the embodiment, which is simple and can generate an electron beam with high brightness, high stability and fine control. The grid cover 14 can protect the emitter 11 and facilitate the stabilization of the path of the electron beam. The electron beam can be led out through the circular hole in the grid cover 14. The size and shape of the electron beam can be adjusted by changing the size and shape of the circular hole in the grid cover 14. The density of the electron beam can be accurately controlled by connecting the grid control electrode 15 to the outer wall of the grid cover 14.

[0051] Specifically, the emitter 11 is made of single-crystal cerium hexaboride material. The use of single-crystal cerium hexaboride to make the emitter 11 can achieve a higher electron emission rate.

[0052] Specifically, an isolation ring is arranged between the grid cover 14 and the emitter 11. The isolation ring is used to insulate and isolate the grid cover 14 and the emitter 11. Further specifically, the isolation ring is made of ceramic material.

[0053] Specifically, a tantalum cylinder is sleeved on the emitter 11, the inner wall of the tantalum cylinder is attached to the emitter 11, and the heating electrode 12 is welded to the outer wall of the tantalum cylinder.

[0054] In one embodiment, as shown in Figure 2 The focusing assembly 2 comprises a first focusing cylinder 21, a second focusing cylinder 22, a first focusing electrode 23, a second focusing electrode 24 and an insulating gasket 25. The first focusing cylinder 21 and the second focusing cylinder 22 are connected by the insulating gasket 25. The centers of the first focusing cylinder 21, the insulating gasket 25 and the second focusing cylinder 22 are provided with circular through holes extending in the axial direction. The first focusing electrode 23 is connected to the outer wall of the first focusing cylinder 21, and the second focusing electrode 24 is connected to the outer wall of the second focusing cylinder 22.

[0055] The focusing assembly 2 of the embodiment has simple structure, and the focusing of the electron beam can be accurately controlled by changing the voltage difference between the first focusing electrode 23 and the second focusing electrode 24 and the corresponding focusing cylinders. Meanwhile, the insulating gasket 25 is used to ensure the electrical isolation between the first focusing cylinder 21 and the second focusing cylinder 22 and allow the electron beam to pass through the circular through hole thereon.

[0056] Specifically, the focusing cylinders are made of stainless steel material. The insulating gasket 25 is made of ceramic material.

[0057] Specifically, the diameter of the circular through hole is 0.5mm to 2mm.

[0058] In one embodiment, the microfocus X-ray device further comprises a heat dissipation base body 5, and the target 4 is arranged on the heat dissipation base body 5.

[0059] In the embodiment, the heat dissipation base body 5 is used to manage the large amount of heat generated by the target 4 under the impact of high-speed electrons, which is conducive to improving the performance, reliability and service life of the microfocus X-ray device.

[0060] Specifically, the heat dissipation base body 5 is made of high heat dissipation performance material, such as single crystal diamond or polycrystalline diamond, preferably single crystal diamond.

[0061] Specifically, the target 4 is made of tungsten, molybdenum or copper material, preferably tungsten material.

[0062] Specifically, the microfocus X-ray device further comprises a base, and the heat dissipation base body 5 is arranged on the base. Further specifically, the base is made of copper material.

[0063] The above only describes the preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A microfocus X-ray apparatus, characterized by The micro-focus X-ray device comprises an electron beam generator, a focusing assembly, a lens assembly and a target, The electron beam generator is used for emitting an electron beam, the focusing assembly, the lens assembly and the target are arranged on one side of the emission end of the electron beam generator and are arranged in sequence along the electron motion direction of the electron beam; The lens assembly comprises two electron optical lenses, the two electron optical lenses are arranged in sequence along the electron motion direction, the pole plates of the two electron optical lenses are aligned along the electron motion direction, and the polarities of the aligned two pole plates are opposite. The electron beam emitted by the electron beam generator is bombarded onto the target after sequentially passing through the focusing assembly and the lens assembly, thereby generating a micro-focus X-ray.

2. The microfocus X-ray apparatus according to claim 1, characterized in that The electron optical lens is an electrostatic lens or a magnetic lens.

3. The microfocus X-ray apparatus according to claim 1 or 2, characterized in that The electron optical lens has at least four pole plates, the pole plates comprise anode pole plates and cathode pole plates, the number of the anode pole plates is the same as that of the cathode pole plates, and the anode pole plates and the cathode pole plates are uniformly and alternately arranged around the central axis of the electron optical lens.

4. The microfocus X-ray apparatus according to claim 3, characterized in that The interval between the aligned two pole plates is 10mm to 20mm.

5. The microfocus x-ray apparatus of claim 3, wherein, The adjacent two pole plates in the electron optical lens are provided with a separation strip.

6. The microfocus x-ray apparatus of claim 3, wherein, The shape of the pole plate is a round stick, a concave circle, a plane or a rod.

7. The microfocus X-ray apparatus as claimed in claim 1 or 2, characterized in that, The electron beam generator comprises an emitter, a heating electrode, a base, a grid cover and a grid control electrode, The heating electrode is arranged on the base; one end of the heating electrode is connected with the emitter to heat the emitter to make it emit electrons; the grid cover is arranged on the outer periphery of the emitter, the grid cover is provided with a circular hole for leading out the electron beam; the grid control electrode is connected to the outer wall of the grid cover to control the density of the electron beam.

8. The microfocus x-ray apparatus of claim 5, wherein, A separation ring is arranged between the grid cover and the emitter.

9. The microfocus X-ray apparatus as claimed in claim 1 or 2, characterized in that, The focusing assembly comprises a first focusing cylinder, a second focusing cylinder, a first focusing electrode, a second focusing electrode and an insulating gasket, The first focusing cylinder and the second focusing cylinder are connected through the insulating gasket, the centers of the first focusing cylinder, the insulating gasket and the second focusing cylinder are provided with circular through holes extending in the axial direction, the first focusing electrode is connected to the outer wall of the first focusing cylinder, and the second focusing electrode is connected to the outer wall of the second focusing cylinder.

10. The microfocus X-ray apparatus as claimed in claim 1 or 2, characterized in that, The micro-focus X-ray device further comprises a heat dissipation base, and the target is arranged on the heat dissipation base.

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