High-energy micro-focus x-ray tube

Abstract

A high-energy micro-focus X-ray tube, comprising: a tube casing (1); a cathode assembly (3); an electron beam confinement assembly (4), the electron beam confinement assembly (4) being coaxially arranged at an electron emission end (31) of the cathode assembly (3), and the electron beam confinement assembly (4) being electrically connected to an electrical plug-in structure; a high-speed bearing assembly (6); and a rotary anode (7), the rotary anode (7) comprising an anode shank (71), a thermal deposition disc (72), a heat conduction layer (73) and a target surface layer (74). The rotary anode (7) is a reflective target structure; a small included angle is formed between an inclined surface of the target surface layer (74) and the axis of the anode shank (71), ranging from nearly parallel to 30 degrees; an included angle between the axis of the electron beam confinement assembly (4) and the inclined surface of the target surface layer (74) is not greater than 10 degrees. The high-energy micro-focus X-ray tube can withstand higher target surface power density due to fast heat dissipation while providing a larger irradiation range and smaller FOD, thus providing higher X-ray photon brightness, which means higher testing efficiency.

Description

High-energy microfocus X-ray tube Technical Field

[0001] The present invention relates to the technical field of X-ray tubes, and in particular to a high-energy microfocus X-ray tube. Background Art

[0002] Industrial X-ray (DR), computed tomography (CT), and micro-area X-ray fluorescence spectrometers based on microfocus technology are increasingly being used for scanning and inspecting various samples. They can reveal the internal structure, defects, density, and other characteristics of the inspected objects at the micron or submicron level, as well as analyze the micro-area composition of materials. They are widely used in the electronics, automotive, aerospace, medical, and metrology industries, as well as in scientific research fields such as analytical science, materials science, life science, and geological science. Currently, foreign transmission microfocus X-ray tubes can achieve a focal spot of 2μm at 160 or 225kV, while reflection microfocus X-ray tubes can achieve a focal spot of 4μm at 160-320kV. Transmission targets have high resolution but low target power, while reflection targets can handle higher power than transmission targets. However, when electrons bombard the target surface, more than 99% of the power is converted into heat deposition on the target surface, causing an excessively high instantaneous temperature rise, which can cause the target surface to melt or vaporize. Therefore, the unit power density of the electron bombardment area is typically 1-2W / μm. 2 Therefore, existing microfocus X-ray tubes use fixed transmission or reflection targets, with low overall power. Limited by the low tube current value, the luminous flux (brightness) is insufficient. CT imaging of an object usually takes several hours or even dozens of hours, and due to the insufficient luminous flux, it cannot be used in micro-area X-ray fluorescence spectrometers.

[0003] Based on the research of the literature "Study on Rotating Radiation Conversion Target for High Energy Microfocus Industrial CT", at the electron energy of 6MeV, the -5 Within 100 μm of electron bombardment, the temperature in the local area will rise to 3376°C within 5 ms, close to the melting point of tungsten. If the duration lasts longer, such as 5 ms, the tungsten target will melt. Therefore, patent CN113225886A proposes a water-cooled rotating radiation conversion target for high-energy microfocus X-rays. However, this gear-driven rotating water-cooled conversion target has a low rotation speed, and the so-called microfocus is actually in the range of 50 μm-400 μm, not a few μm in the true sense. Moreover, this water-cooled transmission target is only suitable for high-energy levels of MeV (1 million electron volts), and will cause significant attenuation of X-rays at the level of hundreds of keV.

[0004] Patent CN115064430A discloses a rotating transmission target microfocus X-ray source and a method for generating X-rays. The source uses a diamond target base, a bevel gear drive to rotate the anode target, and a circulating cooling system to cool the anode target. However, this drive method has a very low rotational speed, and the transmission target cannot be too thick to allow the rays to pass through the target surface. Therefore, the source cannot rely on the heat sink of the target itself, and cannot truly solve the problem of instantaneous high-power-density heat dissipation in high-power-density microfocus X-ray tubes.

[0005] Patent CN113013004A proposes a cold cathode rotating target X-ray tube that adopts the cathode and anode structure of a conventional rotating anode X-ray tube. The anode adopts the conventional rotating reflective target and bearing structure of a CT tube, while the cathode replaces the conventional CT tube's hot cathode with a cold cathode. This focusing structure cannot meet the requirements of a true multi-micron focus. Moreover, the conventional rotating target and bearing structure of a CT tube cannot meet the instantaneous high power density heat dissipation requirements of a high-power density microfocus X-ray tube with a multi-micron focus. As shown in Figure 1, this structure, which draws on the structure of a conventional medical CT tube, has a large angle between the anode target surface O1 and the anode axis O2, typically exceeding 80 degrees. This also results in a small X-ray beam angle, resulting in a small X-ray detection range. In addition, this conventional anode and cathode structure has low X-ray yield efficiency and a large distance between the tube focus and the X-ray window. In other words, the FOD (Focus to Object Distance) of the microfocus tube is very large, which cannot meet the high magnification requirements for tiny defects in microfocus X-ray tube CT imaging applications.

[0006] Summary of the Invention

[0007] In view of the shortcomings of the prior art described above, the technical problem to be solved by the present invention is to provide a high-energy microfocus X-ray tube, which has the characteristics of high power density, fast heat dissipation, high X-ray output, large X-ray beam angle, high brightness and smaller FOD.

[0008] In order to solve the above technical problems, the present invention provides a high-energy microfocus X-ray tube, comprising:

[0009] The tube shell and the tube cavity of the tube shell form a vacuum environment;

[0010] A cathode insulating end sealing assembly is provided at one end of the tube shell and has an electrical plug-in structure;

[0011] a cathode assembly, the cathode assembly being disposed on the cathode insulating end sealing assembly and located in the tube cavity, the cathode assembly being electrically connected to the electrical plug structure;

[0012] an electron beam confinement assembly, the electron beam confinement assembly being coaxially disposed at the electron emission end of the cathode assembly and electrically connected to the electrical plug-in structure;

[0013] An anode insulating end sealing assembly is provided at the other end of the tube shell;

[0014] A high-speed bearing assembly, comprising a bearing stator mounted on the anode insulating end seal assembly and a bearing sleeve rotatably mounted on the bearing stator, wherein the bearing sleeve rotates relative to the bearing stator at a speed of not less than 3000 rpm;

[0015] A rotating anode comprising an anode shank, a heat deposition disk, a heat conductive layer, and a target surface layer. One end of the anode shank is coaxially disposed on the bearing sleeve, and the heat deposition disk is coaxially disposed on the other end of the anode shank. The heat conductive layer is formed on the end surface of the heat deposition disk facing away from the anode shank, and the target surface layer is formed on the heat conductive layer. The maximum diameter of the heat deposition disk is not less than 70 mm, the thickness of the heat conductive layer is 100-2000 μm, and the thickness of the target surface layer is 5-30 μm. The heat conductive layer is made of a high thermal conductivity material, and the heat deposition disk is made of a high heat capacity material.

[0016] The rotating anode is a reflective target structure. The angle between the inclined surface of the target surface and the axis of the anode shank is no greater than 30 degrees, and the angle between the axis of the electron beam confinement assembly and the inclined surface of the target surface is no greater than 10 degrees. Electrons generated by the electron emitter are subjected to the multi-stage confinement of the electron beam confinement assembly, producing an X-ray focal spot with a diameter of 1-9 μm on the target surface. The projection position of the electron emitter on the target surface along the axis of the anode shank is denoted as point F1, and the position of the center of the X-ray focal spot on the target surface is denoted as point F2. The distance between point F2 and the axis of the anode shank is greater than the distance between point F1 and the axis of the anode shank. This arrangement places point F2 closer to the X-ray exit window on the tube shell, thereby providing a smaller field of view (FOD). It also causes the electron beam to strike the target surface at a very small deviation angle relative to the normal of the X-ray exit window, thereby providing a higher X-ray yield and a wider range of X-ray beam output angles.

[0017] Preferably, the electron beam confinement assembly includes an assembly housing that covers the electron emitting end. The assembly housing has an emission opening aligned with the electron emitting end. A first grid, a second grid, a first focusing electrode, and a second focusing electrode are coaxially arranged in sequence within the assembly housing, with the first grid coaxially aligned with the electron emitting end. Insulating supports are sandwiched between the electron emitting end and the first grid, between the first grid and the second grid, between the second grid and the first focusing electrode, and between the first and second focusing electrodes. With this arrangement, a beam spot size of 1-9 microns can be achieved on the target surface using multi-stage focusing.

[0018] Preferably, the electron emitter includes an emitter housing and an electron emitter head arranged in the emitter housing. The emitter housing is located in the component housing and is connected to the component housing through an ear plate.

[0019] Preferably, the heat-conducting layer is attached to the thermal deposition disk by a brazing process, and the target surface layer is attached to the heat-conducting layer by a magnetron sputtering or evaporation process.

[0020] Preferably, the cathode insulating end seal assembly includes a sealing tube, a sealing ring and an electrical connector. One end of the sealing tube is sealed and plugged into one end of the tube shell. The cross section of the sealing ring is groove-shaped. The sealing ring includes a groove bottom, an inner wall portion formed on the radial inner side of the groove bottom, and an outer wall portion formed on the radial outer side of the groove bottom. The groove bottom and the outer wall portion of the sealing ring are both sealedly connected to the other end of the sealing tube, and the inner wall portion is sealedly connected to the outer periphery of the electrical connector.

[0021] Preferably, the cathode assembly further comprises a cantilever, one end of the cantilever is in a sleeve shape to be fixedly sleeved on the sealing ring, and the other end of the cantilever has a locking protrusion, which is fixedly engaged with the electron beam confinement assembly.

[0022] Preferably, the cantilever is provided with an escape opening for allowing the electrode connecting wire to pass through.

[0023] Preferably, the cantilever includes a fixed arm and a swing arm, one end of the fixed arm being sleeve-shaped for fixedly fitting over the sealing ring, and the swing arm being rotatably connected to the other end of the fixed arm via an angle adjuster, with the electron beam confinement assembly being mounted on the swing arm. This arrangement facilitates operator adjustment of the angle between the axis of the electron confinement assembly and the inclined surface of the target surface layer, ensuring that the angle is no greater than 10 degrees.

[0024] Preferably, the electrical connector includes a sealing disk and a plurality of conductive rods sealed and passed through the sealing disk. The outer periphery of the sealing disk is sealed and connected to the inner wall of the sealing ring. A part of the conductive rods are electrically connected to the electron emission end, and the remaining conductive rods are electrically connected to the electron beam confinement assembly.

[0025] Preferably, the target surface layer is made of one or a combination of tungsten, molybdenum, rhodium, rhenium, gold, silver, copper, platinum, iron, titanium, cobalt, and chromium; the thermal conductive layer is made of one or a combination of diamond and high-thermal-conductivity ceramics; and the thermal deposition disk is made of one or a combination of graphite and glassy carbon. This configuration, combining the high thermal conductivity of diamond with the high power density capability of the rotating anode, allows the target surface layer to withstand higher input electron density and a smaller spot size. Combined with the structural design for higher X-ray yield, this provides higher light flux, and therefore higher brightness. This improves detection efficiency and facilitates further application in MicroXRF.

[0026] As described above, the high-energy microfocus X-ray tube of the present invention has the following beneficial effects: the rotating anode, through the provision of its own heat deposition disk and heat conductive layer, increases its heat capacity and improves its heat dissipation efficiency, thereby providing a prerequisite for high-power density electron beam energy input to the rotating anode; the rotational speed of the bearing sleeve relative to the bearing stator is not less than 3000 rpm, which lays a foundation for the long-term operation of the high-energy microfocus X-ray tube; the axis of the electron beam confinement assembly is arranged at a small angle to the target surface layer of the rotating anode, thereby reducing the field of view (FOD) and thus improving the magnification; it also increases the X-ray yield and brightness, thereby improving detection efficiency; and it can provide a large X-ray beam output angle, thereby expanding the X-ray detection range. The present invention can provide a high-energy microfocus X-ray tube with high power density, low FOD, high X-ray yield, high brightness, a wide beam-out angle range, and a rotating anode as a reflective target structure. This overcomes the shortcomings of traditional fixed-anode microfocus X-ray tubes, such as low anode input power, low power density, and long imaging time. It also avoids the shortcomings of traditional transmission-target and improved transmission-target microfocus X-ray tubes, which cannot achieve truly high power density due to the fixed target surface and low target surface rotation speed. It also avoids the shortcomings of high-energy (MeV-level) water-cooled rotating transmission targets, such as large attenuation, not having a true multi-micron focus, and being unsuitable for CT imaging detection of multi-micron-level defects. Therefore, the present invention provides a high-energy microfocus X-ray tube that combines the characteristics of high power density, fast heat dissipation, smaller FOD, high X-ray yield, high brightness, and a wide X-ray beam-out angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG1 is a schematic diagram showing the structure of an existing CT tube.

[0028] FIG2 is a cross-sectional view of the high energy microfocus X-ray tube of the present invention when in use.

[0029] FIG3 is an enlarged view of portion A in FIG2 .

[0030] FIG4 is an enlarged view of portion B in FIG2 .

[0031] FIG5 shows a cross-sectional view of an electron beam confinement assembly.

[0032] Component number description: anode target surface 01, anode axis 02, tube shell 1, tube cavity 11, cathode insulation end seal assembly 2, sealing tube 21, sealing ring 22, groove bottom 221, inner wall 222, outer wall 223, electrical connector 23, sealing disk 231, conductive rod 232, cathode assembly 3, electron emission end 31, emission end housing 311, electron emission head 312, ear plate 313, cantilever 32, clamping protrusion 321, avoidance opening 3 22, fixed arm 323, swing arm 324, angle adjuster 325, electron beam confinement assembly 4, assembly housing 41, emission opening 411, first grid 42, second grid 43, first focusing electrode 44, second focusing electrode 45, anode insulation end seal assembly 5, high-speed bearing assembly 6, bearing stator 61, bearing sleeve 62, rotating anode 7, anode handle 71, thermal deposition disk 72, thermal conductive layer 73, target surface layer 74, X-ray emission window 8. DETAILED DESCRIPTION

[0033] The following describes the implementation of the present invention through specific embodiments. People skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification.

[0034] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the conditions for implementation of the present invention. Therefore, they have no substantial technical significance. Any modification of the structure, change in the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the efficacy and purpose of the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" quoted in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present invention. Changes or adjustments in their relative relationships should also be regarded as the scope of implementation of the present invention without substantially changing the technical content.

[0035] As shown in FIG2 , the present invention provides a high-energy microfocus X-ray tube, comprising:

[0036] The tube shell 1, wherein the tube cavity 11 of the tube shell 1 forms a vacuum environment; the tube shell 1 is provided with an X-ray emission window 8 to allow X-rays to pass through the tube shell 1;

[0037] The cathode insulating end sealing assembly 2 (its specific structure is shown in FIG3 ) is provided at one end of the tube shell 1 and has an electrical plug-in structure;

[0038] a cathode assembly 3, the cathode assembly 3 being provided on the cathode insulating end sealing assembly 2 and located in the tube cavity 11, and the cathode assembly 3 being electrically connected to the electrical plug structure;

[0039] An electron beam confinement assembly 4 (see FIG5 for its specific structure), the electron beam confinement assembly 4 is coaxially arranged at the electron emission end 31 of the cathode assembly 3, and the electron beam confinement assembly 4 is electrically connected to the electrical plug structure;

[0040] An anode insulating end sealing assembly 5 is provided at the other end of the tube shell 1;

[0041] The high-speed bearing assembly 6 includes a bearing stator 61 provided on the anode insulating end seal assembly 5 and a bearing sleeve 62 rotatably sleeved on the bearing stator 61. The rotational speed of the bearing sleeve 62 relative to the bearing stator 61 is not less than 3000 rpm.

[0042] The rotating anode 7 includes an anode shank 71, a heat deposition disk 72, a heat conductive layer 73, and a target surface layer 74. One end of the anode shank 71 is coaxially disposed on the bearing sleeve 62, and the heat deposition disk 72 is coaxially disposed on the other end of the anode shank 71. The heat conductive layer 73 is formed on the end surface of the heat deposition disk 72 facing away from the anode shank 71. The target surface layer 74 is formed on the heat conductive layer 73. The maximum diameter of the heat deposition disk 72 is not less than 70 mm. The heat conductive layer 73 has a thickness of 100-2000 μm. The thickness of the target surface layer 74 is 5-30 μm. The heat conductive layer 73 is made of a high thermal conductivity material, and the heat deposition disk 72 is made of a high heat capacity material.

[0043] The rotating anode 7 is a reflective target structure, the angle between the inclined surface of the target surface layer 74 and the axis of the anode handle 71 is not greater than 30 degrees, and the angle between the axis of the electron beam confinement assembly 4 and the inclined surface of the target surface layer 74 is not greater than 10 degrees. The electrons generated by the electron emitting end 31 pass through the multi-stage confinement action of the electron beam confinement assembly 4 to generate an X-ray focal spot with a diameter of 1-9 μm on the target surface layer 74. The projection position of the electron emitting end 31 along the axis of the anode handle 71 on the target surface layer 74 is recorded as point F1, and the position of the center point of the X-ray focal spot on the target surface layer 74 is recorded as point F2. The distance between point F2 and the axis of the anode handle 71 is greater than the distance between point F1 and the axis of the anode handle 71 (the positions of points F1 and F2 can also be seen in Figure 4).

[0044] In the present invention, the rotating anode 7 accelerates the heat capacity of the rotating anode 7 and improves the heat dissipation efficiency of the rotating anode 7 through the arrangement of its own heat deposition disk 72 and heat conductive layer 73, thereby providing the prerequisite for the high-power density electron beam input energy of the rotating anode 7; the rotational speed of the bearing sleeve 62 relative to the bearing stator 61 is not less than 3000 rpm, laying the foundation for the long-term operation of the high-energy microfocus X-ray tube; the axis of the electron beam confinement component 4 is arranged at a small angle to the target surface layer 74 of the rotating anode 7, which reduces the FOD, thereby being able to increase the magnification. Therefore, the present invention can provide a high-energy microfocus X-ray tube with high power density, small FOD, and a rotating anode 7 as a reflective target structure, which overcomes the shortcomings of low anode input power, low power density, and long imaging time of traditional fixed anode microfocus X-ray tubes; it also avoids the shortcomings of traditional transmission target and improved transmission target microfocus X-ray tubes that cannot achieve truly high power density due to the fixed target surface and low target surface rotation speed; it also avoids the shortcomings of high-energy (MeV level) water-cooled rotating transmission targets that have large attenuation, are not truly micron-focused, and cannot be used for CT imaging detection of micron-level defects.

[0045] Specifically, one end of the anode shank 71 is coaxially disposed with the bearing sleeve 62, and the bearing sleeve 62 rotates at a speed of no less than 3000 rpm relative to the bearing stator 61. With this configuration, the high-speed rotation of the rotating anode, which has a reflective target structure, causes electron bombardment on the target surface layer 74 to form a circular ring. Compared to existing fixed targets or existing rotatable transmission targets, the rotating anode 7 of the present application can withstand higher target surface power density, allowing for the incidence of electron beams with smaller spot sizes. The rotation speed is preferably 8400 rpm. This configuration ensures that the electron spot of several μm in size no longer bombards a fixed portion of the target surface layer 74 for a long time, but instead forms an annular electron spot band. Taking a 5ms pulse as an example, assuming a diameter of 70mm for the electron-bombarded portion, at 3000 rpm, due to the high-speed rotation of the rotating anode 7, the electron beam sweeps over a spot area of ​​nearly 9000 μm within 5ms, thereby dispersing heat within the 9000 μm sweep range, significantly increasing the load-bearing area and thereby reducing the temperature of the electron-bombarded portion of the target surface layer 74. The higher the rotational speed, the larger the diameter of the heat deposition disk 72, the larger the sweep range, and the greater the power it can withstand. Under the same focus of several μm, the tube current is also greater, thereby reducing imaging time and greatly improving efficiency in CT imaging applications. The high-speed bearing assembly 6 can be configured as a liquid metal bearing. This configuration, unlike traditional ball bearings, uses the high thermal conductivity of liquid metal to quickly conduct heat from the heat deposition disk 72 of the rotating anode 7 to the outside of the high-energy microfocus X-ray tube, reducing the temperature of the heat deposition disk 72, thereby enabling the target surface layer 74 to withstand a higher target power density, providing a basic prerequisite for the long-term and reliable operation of the high-energy microfocus X-ray tube. Preferably, the anode shank 71 is integrally formed with the bearing sleeve 62, and the material of the anode shank 71 is consistent with the material of the bearing sleeve 62.

[0046] The rotating anode 7 comprises a multi-layer structure from the outside in. The first layer serves as the target surface layer 74, which withstands electron bombardment and generates X-rays. The second layer, a heat-conducting layer 73, is made of a high-thermal-conductivity material, rapidly dissipating the instantaneous high energy generated by the electron beam bombardment of the first layer. The third layer, a heat-deposition disk 72, is made of a high-heat-capacity material, enabling the high-energy microfocus X-ray tube to operate continuously for extended periods without causing excessive temperature rise in the target surface layer 74. To achieve a balance between X-ray generation and heat dissipation efficiency, the thickness of the target surface layer 74 ranges from 5 to 30 μm, varying with the tube voltage level of the high-energy microfocus X-ray tube. To ensure that heat generated by the electron beam-bombarded portion of the target surface layer 74 is quickly transferred to the heat-deposition disk 72, the thickness of the heat-conical layer 73 ranges from 100 to 2000 μm. The maximum diameter of the heat-deposition disk 72 is no less than 70 mm (the heat-deposition disk 72 is frustum-shaped). By providing a heat-conducting layer with high thermal conductivity, the heat generated by the electron beam bombarding the target surface is quickly conducted away compared to conventional rotating anode targets, enabling the target surface to withstand higher power density. Furthermore, at high rotational speeds, a larger diameter allows the electrons to strike a larger area within a given timeframe, reducing the power per unit area. This means the rotating anode 7 can withstand a higher power density. The rotating anode 7 is a reflective target structure. The angle α between the inclined surface of the target surface layer 74 and the axis of the anode handle 71 is no greater than 30 degrees, preferably no greater than 20 degrees. The angle β between the axis of the electron beam confinement assembly 4 and the inclined surface of the target surface layer 74 is no greater than 10 degrees, preferably 3-7 degrees. Electrons generated by the electron emitting end 31 are subjected to the multi-stage confinement of the electron beam confinement assembly 4, producing an X-ray focal spot with a diameter of 1-9 μm on the target surface layer 74. The projected position of the electron emitting end 31 on the target surface layer 74 along the axis of the anode handle 71 is denoted as point F1, and the position of the center of the X-ray focal spot on the target surface layer 74 is denoted as point F2. The distance between point F2 and the axis of the anode handle 71 is greater than the distance between point F1 and the axis of the anode handle 71. This configuration fully utilizes the effective focal spot size in the projection direction caused by the inclination of the target surface layer 74, making the actual electron bombardment area much larger than the actual effective focal spot area, thereby achieving a greater target surface power tolerance for the target surface layer 74. More importantly, a greater X-ray yield can be obtained under the same incident power, which is also beneficial to reducing CT imaging time; at the same time, the F2 point is made closer to the X-ray exit window 8 on the tube shell 1, thereby providing a smaller FOD; and the X-rays are emitted at a very small deviation angle relative to the normal of the X-ray exit window, thereby providing a higher X-ray yield and a larger X-ray beam angle range, increasing the imaging magnification, and being more conducive to detecting tiny defects in the sample.Finally, there is one more point, specifically referring to FIG2 . Because the axis of the electron beam confinement assembly 4 is arranged at a small angle to the inclined surface of the target surface layer 74 , the electron beam will be deflected by the potential difference between the electron emitting end 31 and the rotating anode, and will eventually hit the target surface layer at a relatively small angle relative to the normal of the X-ray emission window 8 , thereby causing the X-rays to be emitted at a very small deviation angle relative to the normal of the X-ray emission window.

[0047] Therefore, the present invention provides a high-energy microfocus X-ray tube, which has the characteristics of high power density, fast heat dissipation, high X-ray yield, large X-ray beam angle, high brightness and smaller FOD.

[0048] As shown in Figure 5, to improve structural compactness, the electron beam confinement assembly 4 includes an assembly housing 41 that covers the electron emitter 31. Assembly housing 41 has an emission opening 411 aligned with the electron emitter 31. Assembly housing 41 houses a first grid 42, a second grid 43, a first focusing electrode 44, and a second focusing electrode 45, which are coaxially arranged in sequence. The first grid 42 is coaxially aligned with the electron emitter 31. Insulating supports (not shown) are sandwiched between the electron emitter 31 and the first grid 42, between the first grid 42 and the second grid 43, between the second grid 43 and the first focusing electrode 44, and between the first focusing electrode 44 and the second focusing electrode 45. Assembly housing 41 protects not only the internal structure of the electron beam confinement assembly 4 (the grids and focusing electrodes), but also the electron emitter 31. Furthermore, the electron emitter 31 can be connected to assembly housing 41, which simplifies the connection structure of the cathode assembly 3 for mounting the electron emitter 31. During use, by applying different potentials relative to the electrode potential of the electron emitting end 31 to the first grid, the second grid, the first focusing electrode, and the second focusing electrode, a preset anode potential is applied to the rotating anode 7, thereby confining the electrons emitted from the electron emitting end 31 into electron spots of several microns in size and bombarding the target surface layer 74. The insulating support may be a ceramic support structure.

[0049] In order to arrange the electron emitter 31 in the component housing 41 , the electron emitter 31 includes an emitter housing 311 and an electron emitter head 312 arranged in the emitter housing 311 . The emitter housing 311 is located in the component housing 41 and is connected to the component housing 41 through an ear plate 313 .

[0050] In order to improve the thermal conductivity of the rotating anode 7 , the thermal conductive layer 73 is attached to the thermal deposition disk 72 by a brazing process, and the target surface layer 74 is attached to the thermal conductive layer 73 by a magnetron sputtering or evaporation process.

[0051] As shown in Figure 3, in order to form a vacuum environment in the tube cavity 11 of the tube shell 1 and to form an electrical plug-in structure for the cathode insulating end sealing assembly 2, the cathode insulating end sealing assembly 2 includes a sealing tube 21, a sealing ring 22 and an electrical connector 23. One end of the sealing tube 21 is sealed and plugged into one end of the tube shell 1. The cross-section of the sealing ring 22 is groove-shaped. The sealing ring 22 includes a groove bottom 221, an inner wall portion 222 formed on the radial inner side of the groove bottom 221, and an outer wall portion 223 formed on the radial outer side of the groove bottom 221. The groove bottom 221 and the outer wall portion 223 of the sealing ring 22 are both sealed and connected to the other end of the sealing tube 21, and the inner wall portion 222 is sealed and connected to the outer periphery of the electrical connector 23.

[0052] To facilitate assembly, the cathode assembly 3 further includes a cantilever 32 . One end of the cantilever 32 is sleeve-shaped and fixedly sleeved on the sealing ring 22 . The other end of the cantilever 32 has a latch 321 , which is latched and fixed to the electron beam confinement assembly 4 .

[0053] In order to facilitate the electrical connection of the electron emission end 31 and the anode insulating end sealing assembly 5 to the electrical connector 23, the cantilever 32 is provided with an escape opening 322 for allowing the electrode connection wire (the electrode connection wire is an existing structure) to pass through.

[0054] To adjust the angle β between the axis of the electron beam confinement assembly 4 and the inclined surface of the target surface layer 74, the cantilever 32 includes a fixed arm 323 and a swing arm 324. One end of the fixed arm 323 is in the shape of a sleeve and fixedly mounted on the sealing ring 22. The swing arm 324 is rotatably connected to the other end of the fixed arm 323 via an angle adjuster 325. The electron beam confinement assembly 4 is mounted on the swing arm 324. The angle adjuster 325 is an existing structure and will not be described in detail.

[0055] To simplify the structure of the electrical connector 23, the electrical connector 23 includes a sealing disk 231 and a plurality of conductive rods 232 that are hermetically disposed through the sealing disk 231. The outer periphery of the sealing disk 231 is hermetically connected to the inner wall portion 222 of the sealing ring 22. Some of the conductive rods 232 are electrically connected to the electron emitting end 31, and the remaining conductive rods 232 are electrically connected to the electron beam confinement assembly 4. The sealing disk 231 hermetically isolates the vacuum inside the tube shell 1 from the non-vacuum inside the tube shell 1.

[0056] In order to improve the heat dissipation and thermal conductivity of the rotating anode 7, the material of the target surface layer 74 is one or a combination of tungsten, molybdenum, rhodium, rhenium, gold, silver, copper, platinum, iron, titanium, cobalt and chromium; the material of the thermal conductive layer 73 is one or a combination of diamond and high thermal conductivity ceramics; the material of the heat deposition disk 72 is one or a combination of graphite and glassy carbon.

[0057] In summary, the present invention provides a high-energy microfocus X-ray tube that combines high power density, rapid heat dissipation, high X-ray output, a wide X-ray beam angle, high brightness, and a minimal field of view (FOD). Therefore, the present invention effectively overcomes the shortcomings of the prior art and possesses high industrial value.

[0058] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Anyone skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by one of ordinary skill in the art without departing from the spirit and technical principles disclosed herein are intended to be covered by the claims of the present invention.

Claims

1. A high energy microfocus X-ray tube, characterized in that: include: A tube shell (1), wherein a tube cavity (11) of the tube shell (1) forms a vacuum environment; A cathode insulating end sealing component (2), the cathode insulating end sealing component (2) is arranged at one end of the tube shell (1), and the cathode insulating end sealing component (2) has an electrical plug-in structure; A cathode assembly (3), the cathode assembly (3) being arranged on the cathode insulating end sealing assembly (2) and located in the tube cavity (11), and the cathode assembly (3) being electrically connected to the electrical plug-in structure; An electron beam confinement component (4), the electron beam confinement component (4) is coaxially arranged at the electron emission end (31) of the cathode component (3), and the electron beam confinement component (4) is electrically connected to the electrical plug-in structure; An anode insulating end sealing assembly (5), the anode insulating end sealing assembly (5) being arranged at the other end of the tube shell (1); A high-speed bearing assembly (6), the high-speed bearing assembly (6) comprising a bearing stator (61) arranged on the anode insulating end seal assembly (5) and a bearing sleeve (62) rotatably sleeved on the bearing stator (61), wherein the rotation speed of the bearing sleeve (62) relative to the bearing stator (61) is not less than 3000 revolutions per minute; A rotating anode (7), the rotating anode (7) comprising an anode handle (71), a heat deposition disk (72), a heat conductive layer (73) and a target surface layer (74), one end of the anode handle (71) being coaxially arranged on a bearing sleeve (62), the heat deposition disk (72) being coaxially arranged on the other end of the anode handle (71), the heat conductive layer (73) being formed on the end surface of the heat deposition disk (72) facing away from the anode handle (71), the target surface layer (74) being formed on the heat conductive layer (73), the maximum diameter of the heat deposition disk (72) being not less than 70 mm, the thickness of the heat conductive layer (73) being 100-2000 μm, the thickness of the target surface layer (74) being 5-30 μm, the heat conductive layer (73) being made of a material with high thermal conductivity, and the heat deposition disk (72) being made of a material with high heat capacity; The rotating anode (7) is a reflective target structure, the angle between the inclined surface of the target surface layer (74) and the axis of the anode handle (71) is not greater than 30 degrees, the angle between the axis of the electron beam confinement component (4) and the inclined surface of the target surface layer (74) is not greater than 10 degrees, the electrons generated by the electron emission end (31) are subjected to the multi-stage confinement effect of the electron beam confinement component (4), and an X-ray focal spot with a diameter of 1-9 μm is generated on the target surface layer (74), the projection position of the electron emission end (31) along the axis of the anode handle (71) on the target surface layer (74) is recorded as point F1, the position of the center point of the X-ray focal spot on the target surface layer (74) is recorded as point F2, and the distance between point F2 and the axis of the anode handle (71) is greater than the distance between point F1 and the axis of the anode handle (71).

2. The high energy microfocus X-ray tube according to claim 1, characterized in that: The electron beam confinement component (4) comprises a component housing (41) covering an electron emission end (31), the component housing (41) having an emission opening (411) aligned with the electron emission end (31), a first grid (42), a second grid (43), a first focusing electrode (44) and a second focusing electrode (45) coaxially arranged in sequence are arranged in the component housing (41), the first grid (42) is coaxially aligned with the electron emission end (31); an insulating support body is sandwiched between the electron emission end (31) and the first grid (42), between the first grid (42) and the second grid (43), between the second grid (43) and the first focusing electrode (44), and between the first focusing electrode (44) and the second focusing electrode (45).

3. The high energy microfocus X-ray tube according to claim 2, characterized in that: The electron emission end (31) comprises an emission end housing (311) and an electron emission head (312) arranged in the emission end housing (311); the emission end housing (311) is located in the component housing (41) and is connected to the component housing (41) through an ear plate (313).

4. The high energy microfocus X-ray tube according to claim 1, characterized in that: The heat-conducting layer (73) is attached to the heat deposition disk (72) by a brazing process, and the target surface layer (74) is attached to the heat-conducting layer (73) by a magnetron sputtering or evaporation process.

5. The high energy microfocus X-ray tube according to claim 1, characterized in that: The cathode insulating end seal assembly (2) comprises a sealing tube (21), a sealing ring (22) and an electrical connector (23); one end of the sealing tube (21) is sealed and plugged into one end of the tube shell (1); the cross section of the sealing ring (22) is in the shape of a groove; the sealing ring (22) comprises a groove bottom (221), an inner wall portion (222) formed on the radial inner side of the groove bottom (221) and an outer wall portion (223) formed on the radial outer side of the groove bottom (221); the groove bottom (221) and the outer wall portion (223) of the sealing ring (22) are both sealed and connected to the other end of the sealing tube (21); and the inner wall portion (222) is sealed and connected to the outer peripheral edge of the electrical connector (23).

6. The high energy microfocus X-ray tube according to claim 5, characterized in that: The cathode assembly (3) further comprises a cantilever (32), one end of the cantilever (32) is in the shape of a sleeve and is fixedly sleeved on the sealing ring (22), and the other end of the cantilever (32) has a locking protrusion (321), and the locking protrusion (321) is fixedly engaged with the electron beam confinement assembly (4).

7. The high energy microfocus X-ray tube according to claim 6, characterized in that: The cantilever (32) is provided with an avoidance opening (322) for allowing the electrode connection line to pass through.

8. The high energy microfocus X-ray tube according to claim 6, characterized in that: The cantilever (32) comprises a fixed arm (323) and a swing arm (324); one end of the fixed arm (323) is in the shape of a sleeve and is fixedly sleeved on the sealing ring (22); the swing arm (324) is rotatably connected to the other end of the fixed arm (323) via an angle adjuster (325); and the electron beam confinement assembly (4) is provided on the swing arm (324).

9. The high energy microfocus X-ray tube according to claim 5, characterized in that: The electrical connector (23) comprises a sealing disk (231) and a plurality of conductive rods (232) sealingly disposed in the sealing disk (231); the outer periphery of the sealing disk (231) is sealedly connected to the inner wall portion (222) of the sealing ring (22); a portion of the conductive rods (232) are electrically connected to the electron emission end (31); and the remaining conductive rods (232) are electrically connected to the electron beam confinement component (4).

10. The high energy microfocus X-ray tube according to claim 1, characterized in that: The material of the target surface layer (74) is one or a combination of tungsten, molybdenum, rhodium, rhenium, gold, silver, copper, platinum, iron, titanium, cobalt and chromium; the material of the heat conductive layer (73) is one or a combination of diamond and high thermal conductivity ceramics; and the material of the heat deposition disk (72) is one or a combination of graphite and glassy carbon.

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