Anode assembly for an X-ray tube and an X-ray tube

Abstract

An anode assembly for an X-ray tube and an X-ray tube, wherein the anode assembly for the X-ray tube includes: an anode target having a bombardment surface for receiving an electron beam emitted in a first direction to generate X-rays; a first nanostructure layer covering at least the bombardment surface, the first nanostructure layer being configured to absorb first electrons at the bombardment surface. By adopting the technical solution of the present application, the service life of the X-ray tube can be extended and the working efficiency of the X-ray tube can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of X-ray tubes, and in particular, to an anode assembly for an X-ray tube and an X-ray tube. Background Art

[0002] The X-ray tube is a core component of a CT system, which mainly includes two major parts: a cathode and an anode. During the operation of the X-ray tube, a current is applied to the filament of the cathode assembly to heat it and generate a large number of electrons, and a high voltage is applied between the cathode assembly and the anode assembly to form a strong electric field. Under the action of the strong electric field, the active electrons bombard the anode target disk at high speed from the cathode, thereby generating X-rays.

[0003] However, during the operation of the existing X-ray tubes, a large number of electrons will accumulate near both the cathode assembly and the anode assembly. These electrons include the electrons emitted by the filament, the electron cloud formed near the cathode due to the action of the electric field, and the reflected electrons and secondary electrons excited after the electrons bombard the anode target disk. When the electrons accumulate near the cathode assembly and the anode assembly to a certain extent, an arc discharge phenomenon will occur, and the arc discharge will damage the X-ray tube or reduce the service life of the X-ray tube. Summary of the Invention

[0004] The technical problem solved by the present invention is how to extend the service life of the X-ray tube and improve the working efficiency of the X-ray tube.

[0005] To solve at least one of the above technical problems, an embodiment of the present invention provides an anode assembly for an X-ray tube, including: an anode target having a bombardment surface for receiving an electron beam emitted in a first direction to generate X-rays; a first nanostructure layer covering at least the bombardment surface for absorbing first electrons at the bombardment surface.

[0006] Optionally, the first electrons include at least one of the reflected electrons and secondary electrons generated when the electron beam bombards the bombardment surface.

[0007] Optionally, the first nanostructure layer includes at least one first nanotube layer attached to the bombardment surface. The first nanotube layer includes a plurality of first nanotubes extending in the first direction, the first direction is parallel to the bombardment direction of the electron beam, and there is a non-zero angle between the first direction and the normal of the bombardment surface.

[0008] Optionally, the first nanostructure layer includes multiple layers of the first nanotube layer, and the multiple layers of the first nanotube layer are stacked along the first direction.

[0009] Optionally, the plurality of first nanotubes in each layer of the first nanotube layer are distributed in a plane parallel to the bombardment surface.

[0010] Optionally, the diameters of the first nanotubes are the same or the diameter of at least one of the first nanotubes is different from the diameters of other first nanotubes.

[0011] Optionally, the diameter of each of the first nanotubes is within the range of [0.5, 5] nanometers.

[0012] Optionally, end surfaces of the plurality of first nanotubes facing the first direction are flush.

[0013] Optionally, the gap between adjacent first nanotubes is less than 2 nanometers.

[0014] Optionally, each of the first nanotubes has an opening along the first direction toward a side away from the anode target, and electrons in the electron beam enter the first nanotube from the opening and generate the first electrons after bombarding the bombardment surface. The first electrons are reflected or absorbed between inner walls of the first nanotubes.

[0015] Optionally, the length of each of the first nanotubes along the first direction is between [50, 100] nanometers.

[0016] Optionally, the anode assembly further includes: a heat storage structure, which is arranged on the other side of the anode target where the bombardment surface is formed, and the first nanostructure layer extends from the bombardment surface to the heat storage structure.

[0017] Optionally, the material of the first nanostructure layer is carbon nanotubes.

[0018] To solve the above technical problems, an embodiment of the present invention further provides an X-ray tube, comprising: the above-mentioned anode assembly; a cathode assembly, comprising: a cathode head, used to cooperate with the anode target to generate a high-voltage electric field; a filament, used to emit an electron beam along a first direction under the action of the high-voltage electric field; a second nanostructure layer, at least covering the end face of the cathode head facing the anode assembly and exposing the filament, the second nanostructure layer being used to absorb second electrons generated by the cathode head.

[0019] Optionally, the second electrons include redundant electrons generated by the cathode head.

[0020] Optionally, along the first direction, a projection of the second nanostructure layer and a projection of the filament do not overlap.

[0021] Optionally, the second nanostructure layer includes: a second nanotube layer, which is attached to the end surface of the cathode head facing the anode assembly, and the second nanotube layer includes a plurality of second nanotubes extending along the first direction.

[0022] Optionally, the diameters of multiple second nanotubes are the same, or the diameter of at least one second nanotube is different from that of the other second nanotubes.

[0023] Optionally, the diameter of each second nanotube ranges from 0.5 to 5 nanometers.

[0024] Optionally, the end faces of multiple second nanotubes facing the anode assembly are flush.

[0025] Optionally, the gap between adjacent second nanotubes is less than 2 nanometers.

[0026] Optionally, after the second electrons generated by the cathode head enter the second nanotubes, they are reflected or absorbed between the inner walls of the second nanotubes.

[0027] Optionally, the second nanostructure layer further includes: a nanofiber layer covering the side of the second nanotube layer away from the cathode head, and the nanofiber layer is used to absorb the second electrons in the second nanotubes.

[0028] Optionally, the nanofiber layer includes multiple stacked sub-fiber layers, and the number of layers of the sub-fiber layer ranges from 5 to 10 layers.

[0029] Optionally, the thickness of the nanofiber layer in the first direction ranges from 30 to 50 nanometers.

[0030] Optionally, the second nanostructure layer is a carbon nanostructure layer.

[0031] Optionally, the end face of the cathode head facing the anode assembly is perpendicular to the first direction.

[0032] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0033] The embodiment of the present invention provides an anode assembly for an X-ray tube, including: an anode target having a bombardment surface for receiving an electron beam emitted in a first direction to generate X-rays; a first nanostructure layer at least covering the bombardment surface, and the first nanostructure layer is used to absorb the first electrons at the bombardment surface.

[0034] By adopting the technical solution of the present application, the first nanostructure layer is arranged on the bombardment surface of the anode target to absorb the first electrons on the bombardment surface, which can reduce the accumulation of electrons near the anode assembly, effectively avoid the occurrence of arc discharge when the electron accumulation reaches a certain level, and further prevent the X-ray tube from being damaged by arc discharge, thereby extending the service life of the X-ray tube.

[0035] Further, the first electrons include reflected electrons and secondary electrons. Absorbing the reflected electrons and secondary electrons can more precisely reduce the problem of arc discharge that may be caused by the aggregation of these electrons, thereby better protecting the X-ray tube and extending its service life. In addition, it can also prevent the first electrons that accumulate near the anode assembly from forming an electron cloud and colliding with the electrons in the electron beam emitted by the cathode, which affects the working efficiency of the X-ray tube.

[0036] Further, the first nanotube layer including multiple first nanotubes is attached to the bombardment surface. The multiple first nanotubes extend along the electron beam bombardment direction and have a non-zero angle with the normal of the bombardment surface. This structure is beneficial for capturing the first electrons generated at the bombardment surface, making the reflected electrons in the first electrons directly shoot towards the inner wall of the first nanotube, thereby more effectively absorbing electrons, reducing electron aggregation, lowering the risk of arc discharge, and extending the life of the X-ray tube.

[0037] Further, multiple layers of the first nanotube layer are stacked and laid along the first direction. Since the tube wall of the first nanotube is relatively thin, the electron beam can still pass through the internal channels of the first nanotubes and the gaps between adjacent first nanotubes. And the first electrons can bounce multiple times between the inner walls of the first nanotubes, increasing the ability of the first nanostructure layer to absorb the first electrons and being able to capture more electrons.

[0038] An embodiment of the present invention also provides an X-ray tube, including: the above-mentioned anode assembly; a cathode assembly, including: a cathode head for cooperating with the anode target to generate a high-voltage electric field; a filament for emitting an electron beam along the first direction under the action of the high-voltage electric field; a second nanostructure layer at least covering the end face of the cathode head facing the anode assembly and exposing the filament, and the second nanostructure layer is used to absorb the second electrons generated by the cathode head.

[0039] Adopting the technical solution of the present application, the X-ray tube includes an anode assembly with a first nanostructure layer and a cathode assembly with a second nanostructure layer, which absorb electrons from both the anode and cathode sides respectively, comprehensively reducing the aggregation of electrons in the X-ray tube, effectively lowering the risk of arc discharge, protecting the X-ray tube, and extending its service life.

[0040] Further, the second electrons are redundant electrons generated by the cathode head. Absorbing these redundant electrons can reduce the aggregation of electrons near the cathode assembly, lower the possibility of arc discharge caused by electron aggregation, protect the X-ray tube, and extend its service life. Description of the Drawings

[0041] Figure 1 is a schematic diagram of an X-ray tube according to an embodiment of the present invention;

[0042] Figure 2 is Figure 1Partial enlarged view of middle region A;

[0043] Figure 3 is Figure 1 Partial enlarged view of middle region B;

[0044] Figure 4 is Figure 1 Schematic diagram of middle cathode head. Specific implementation manners

[0045] As described in the background art, during the operation of the existing X-ray tube, a large number of electrons will accumulate near both the cathode assembly and the anode assembly, and it is easy to occur an arc discharge phenomenon, which may damage the X-ray tube or reduce the service life of the X-ray tube. In addition, the electron cloud formed by the electron accumulation may also collide with the electrons in the electron beam, affecting the working efficiency of the X-ray tube.

[0046] To solve the above technical problems, an embodiment of the present invention provides an anode assembly for an X-ray tube, including: an anode target having a bombarding surface for receiving an electron beam emitted along a first direction to generate X-rays; a first nanostructure layer covering at least the bombarding surface, and the first nanostructure layer is used to absorb the first electrons at the bombarding surface.

[0047] Adopting the technical solution of the present application, by providing a first nanostructure layer on the bombarding surface of the anode target to absorb the first electrons at the bombarding surface, the accumulation of electrons near the anode assembly can be reduced, effectively avoiding the arc discharge phenomenon when the electron accumulation reaches a certain degree, thereby preventing the X-ray tube from being damaged by arc discharge and prolonging the service life of the X-ray tube.

[0048] To make the above objects, features and beneficial effects of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention will be given with reference to the accompanying drawings.

[0049] Figure 1 is a schematic diagram of an X-ray tube 100 of the present invention, Figure 2 is Figure 1 Partial enlarged view of middle region A.

[0050] Referring to Figure 1 , the X-ray tube 100 may include an anode assembly 10 and a cathode assembly 20. Among them, the cathode assembly 20 is used to emit an electron beam to the anode assembly, and X-rays are formed after the electron beam bombards the anode assembly 10.

[0051] Specifically, the X-ray tube 100 (also known as the X-ray bulb or CT bulb) can be used in X-ray machines in the medical field, such as disease detection instruments like CT scanners. With the development of technology, CT scanners have been popularized due to their high-resolution capabilities and intuitive, accurate diagnostic effects, and are widely used in the medical field. The X-ray tube 100 can be used as a core component in a CT scanner and is widely used in practice to generate X-rays. Therefore, the technical perfection of the X-ray tube 100 directly affects the working effect of the CT scanner.

[0052] In some embodiments, the X-ray tube 100 may include a housing 101. The housing 101 defines a vacuum-containing cavity, and a window structure 102 for X-rays to exit may also be provided on the housing 101.

[0053] Furthermore, in the X-ray tube 100, the principle of X-ray generation is that the filament 5 in the cathode assembly 20 generates electrons by heating. A large number of electrons are accelerated by the high-voltage electric field between the cathode assembly 20 and the anode assembly 10 and bombard the anode assembly 10 to generate X-rays. The X-rays are filtered by the electron emission window 102 and then exit, pass through the patient, and are received by the CT detector for imaging. During the process of electrons bombarding the anode assembly 10, a large amount of heat is generated. If the bombardment position remains unchanged, a large amount of heat will be generated in the bombarded area of the anode assembly 10, and the heat generation rate is much greater than its heat dissipation rate. When the heat accumulates to the critical value, the bombarded area of the target surface melts, causing anode failure. Therefore, in the prior art, a rotating anode is generally used in the X-ray tube, that is, the anode assembly 10 is in a rotating state during operation, so that the position of the electron bombardment on the anode assembly 10 continuously changes, avoiding the phenomenon of local temperature rise damaging the anode assembly 10.

[0054] In some embodiments, in combination with Figure 1 and Figure 2 , the anode assembly 10 for the X-ray tube 100 may include: an anode target 1 having a bombardment surface 11, and the bombardment surface 11 is used to receive an electron beam emitted along the first direction D1 to generate X-rays; a first nanostructure layer 2 that at least covers the bombardment surface 11, and the first nanostructure layer 2 is used to absorb the first electrons at the bombardment surface 11.

[0055] Specifically, the anode target 1 is used to receive an electron beam emitted along the first direction D1 and generate X-rays.

[0056] Furthermore, the anode target 1 has a bombardment surface 11. The bombardment surface 11 is used to receive an electron beam emitted along the first direction D1. When the high-speed electrons in the electron beam bombard the bombardment surface 11, they will interact with the material of the anode target 1, thereby generating X-rays.

[0057] In some embodiments, the anode target 1 can be in a state of high-speed rotation during operation to avoid heat concentration in a fixed area of the anode target 1, resulting in temperature rise and even melting of the target surface. In this scenario, the bombardment surface 11 can be, for example, an annular area on the surface of the anode target 1 facing the electron beam direction.

[0058] In some embodiments, the anode target 1 can be made of high melting point metal materials such as W (tungsten), Mo (molybdenum), and related alloys.

[0059] Furthermore, a first nanostructure layer 2 is covered on the bombardment surface 11. The main function of the first nanostructure layer 2 is to absorb the first electrons at the bombardment surface 11. During the operation of the X-ray tube 100, a large number of electrons, that is, the first electrons, will accumulate at the bombardment surface 11. If the first electrons are not effectively processed, phenomena such as arc discharge may be triggered, causing damage to the X-ray tube 100. The first nanostructure layer 2 can effectively absorb these electrons through its special nanostructure, thereby reducing the accumulation of electrons at the bombardment surface 11 and avoiding the occurrence of adverse phenomena such as arc discharge.

[0060] In a variant, the first nanostructure layer 2 can cover the entire surface of the anode target 1 in the opposite direction of the first direction D1.

[0061] In some embodiments, the first electrons can include at least one of the reflected electrons and the excited secondary electrons generated by the electron beam bombarding the bombardment surface 11. Among them, the bombardment direction of the electron beam can be referred to Figure 2 as shown by the solid arrow in, and the movement trajectory of the reflected electrons can be referred to Figure 2 as shown by the dashed arrow in.

[0062] In practical applications, when the electron beam bombards the bombardment surface 11, some electrons may not interact with the material of the anode target 1 to generate X-rays, but will be reflected back from the bombardment surface 11. If the reflected electrons are not effectively processed, they may accumulate near the anode assembly 10, triggering phenomena such as arc discharge and causing damage to the X-ray tube 100. It is even possible to collide with other electrons in the electron beam, hindering the normal injection of the electron beam and resulting in a decrease in the generation efficiency of X-rays.

[0063] In addition, when the electron beam bombards the bombardment surface 11, in addition to the possible generation of reflected electrons, electrons in the anode target 1 material may also be excited to escape from the material surface, forming secondary electrons. These secondary electrons will also accumulate near the anode assembly 10, posing a threat to the stability and service life of the X-ray tube 100 and affecting the working efficiency of the X-ray tube 100.

[0064] In some embodiments, the first electrons may further include electrons generated by surface states. For example, there may be some surface states on the surface of the anode target 1, and these surface states may release electrons under the bombardment of the electron beam. In addition, the first electrons may also include electrons generated by other physical processes (such as thermionic emission, field emission, etc.) at the bombardment surface 11. These electrons can also be effectively absorbed by the first nanostructure layer 2 to reduce the risk of electron accumulation and arc discharge.

[0065] In some embodiments, the first nanostructure layer 2 may include: at least one first nanotube layer 21 attached to the bombardment surface 11, the first nanotube layer 21 including a plurality of first nanotubes 211 extending along the first direction D1, the first direction D1 being parallel to the bombardment direction of the electron beam, and there being a non-zero angle between the first direction D1 and the normal of the bombardment surface 11.

[0066] Specifically, the first nanotube layer 21 is directly attached to the bombardment surface 11, ensuring close contact between the first nanotubes 211 and the bombardment surface 11, so as to be able to more effectively capture the first electrons generated at the bombardment surface 11.

[0067] Furthermore, the first nanotubes 211 extend along the first direction D1, and the first direction D1 is parallel to the bombardment direction of the electron beam. Thus, the electron beam can pass through the internal channels of the first nanotubes 211 and the gaps between adjacent nanotubes 211 to reach the bombardment surface 11. The first nanotubes 211 do not affect the normal incidence of the electron beam.

[0068] Furthermore, there is a non-zero angle between the first direction D1 and the normal of the bombardment surface 11. Thus, after the reflected electrons leave the bombardment surface 11, they can directly shoot towards the inner wall of the first nanotubes 211, increasing the collision probability between the reflected electrons and the inner wall of the first nanotubes 211, and thus more effectively absorbing electrons.

[0069] Therefore, since the first nanotubes 211 extend along the electron beam bombardment direction and there is an angle with the normal of the bombardment surface 11, the reflected electrons are more easily captured by the nanotubes. When the reflected electrons shoot towards the inner wall of the first nanotubes 211, they will be absorbed or scattered by the material of the first nanotubes 211, thus reducing the accumulation near the bombardment surface 11.

[0070] In some embodiments, the first nanotube layer 21 can be formed by methods such as chemical vapor deposition (CVD), sputtering deposition in physical vapor deposition (PVD), etc. It is also possible to use a template with nanopores as a support and fill the template pores with materials through methods such as electrochemical deposition and sol-gel method to form the first nanotube layer 21. Or utilize the intermolecular interaction forces (such as van der Waals forces, hydrogen bonds, etc.) to spontaneously form an ordered structure of the first nanotube layer 21 or the precursor of the first nanotube layer 21 on the bombardment surface 11.

[0071] In some embodiments, multiple first nanotubes 211 in the first nanotube layer 21 can attract each other through intermolecular interaction forces such as van der Waals forces, hydrogen bonds or electrostatic interactions.

[0072] In some embodiments, multiple first nanotubes 211 can also increase the tightness of the connection by forming hydrogen bonds, physical entanglement or interweaving, etc., thereby enhancing the mechanical strength and stability of the first nanotube layer 21.

[0073] In some embodiments, the first nanostructure layer 2 includes multiple layers of the first nanotube layer 21, and the multiple layers of the first nanotube layer 21 are stacked and laid along the first direction D1. Thus, the multiple layers of the first nanotube layer 21 form a denser and more complex structure on the bombardment surface 11.

[0074] Furthermore, since the wall of the first nanotube 211 is relatively thin, when the electron beam passes through the first nanostructure layer 2, it can still pass through the internal channels of the first nanotubes 211 and the gaps between adjacent first nanotubes 211, which ensures that the electron beam can normally bombard the bombardment surface 11 to generate X-rays.

[0075] Furthermore, when the first electrons (including reflected electrons and excited secondary electrons, etc.) move in the first nanostructure layer 2, the first electrons will bounce multiple times between the inner walls of the first nanotubes 211. This increases the contact opportunity between the first electrons and the inner walls of the first nanotubes 211, thereby improving the ability of the first nanostructure layer 2 to absorb the first electrons.

[0076] Furthermore, the stacked laying of the multiple layers of the first nanotube layer 21 makes the first nanostructure layer 2 have more inner walls of the first nanotubes 211, providing more collision and capture opportunities for the first electrons.

[0077] In some embodiments, the multiple first nanotube layers 21 can be stacked in a staggered manner, that is, the first nanotubes 211 of adjacent two first nanotube layers 21 do not have a one-to-one correspondence relationship, but there is a certain offset. Thus, a more intricate network structure can be formed between the first nanotubes 211, increasing the contact points and cross-sectional areas between the first nanotubes 211, and providing more scattering and trapping paths for the first electrons.

[0078] In some embodiments, the multiple first nanotubes 211 of each first nanotube layer 21 can be distributed in a plane parallel to the bombardment surface 11.

[0079] In some embodiments, the diameters of the multiple first nanotubes 211 are the same or the diameter of at least one first nanotube 211 is different from the diameters of the other first nanotubes 211. For example, in a region where the density and quantity of the first electrons are higher, the diameter of the first nanotubes 211 can be set relatively smaller so that more first nanotubes 211 can be arranged in this region, thereby improving the trapping efficiency of the first electrons.

[0080] In some embodiments, the diameter of each first nanotube 211 is in the range of [0.5, 5] nanometers. Among them, a smaller diameter (such as 0.5 nanometers) can achieve a denser arrangement of the first nanotubes 211 under the same area to improve the trapping efficiency of the first electrons. While a larger diameter (such as 5 nanometers) can reduce the wall thickness of the first nanotubes 211, thus avoiding affecting the injection of the electron beam. Thus, by selecting an appropriate diameter, the electron scattering and trapping capabilities of the first nanostructure layer 2 can be optimized.

[0081] In some embodiments, the end faces of the multiple first nanotubes 211 facing the first direction D1 are flush. Thus, it can be ensured that the nanotube layer forms a flat surface on the bombardment surface 11, which is helpful for the uniform bombardment of the electron beam and the stable generation of X-rays.

[0082] In some embodiments, the gap between adjacent first nanotubes 211 is less than 2 nanometers. Thus, the close arrangement also helps to enhance the connection between the first nanotubes 211 (for example, the van der Waals force increases), improving the overall stability and mechanical strength of the first nanostructure layer 2.

[0083] In some embodiments, each first nanotube 211 has an opening facing away from the anode target 1 along the first direction D1. The electrons in the electron beam enter the first nanotube 211 from the opening, and generate the first electrons after bombarding the bombardment surface 11. The first electrons are reflected or absorbed between the inner walls of the first nanotube 211.

[0084] In some embodiments, the length of each of the plurality of first nanotubes 211 along the first direction D1 ranges from [50, 100] nanometers. Thus, it can ensure that the first nanotubes 211 have sufficient length to effectively scatter and capture electrons, and will not increase the preparation difficulty or reduce the stability of the first nanotube layer 21 due to excessive length.

[0085] In some embodiments, the anode assembly 10 may further include a heat storage structure 3 disposed on the other side of the anode target 1 where the bombardment surface 11 is formed, and the first nanostructure layer 2 extends from the bombardment surface 11 to the heat storage structure 3.

[0086] Specifically, the heat storage structure 3 is disposed on the other side of the anode target 1 where the bombardment surface 11 is formed. When the electron beam bombards the bombardment surface 11, the generated heat is transferred to the heat storage structure 3 through the anode target 1. The heat storage structure 3 can be used to absorb and store the heat generated by the electron beam bombardment, and can quickly absorb and disperse the heat, thereby maintaining the temperature stability of the anode target 1 and the first nanostructure layer 2. Thus, it can avoid the anode target 1 from being damaged due to excessive temperature.

[0087] Furthermore, the first nanostructure layer 2 extends from the bombardment surface 11 to the heat storage structure 3. Thus, it can ensure that the heat can be quickly and evenly transferred to the heat storage structure 3, thereby increasing the heat dissipation effect on the anode target 1 and avoiding local overheating of the anode target 1.

[0088] In some embodiments, the heat storage structure 3 may be made of graphite material.

[0089] In some embodiments, the material of the first nanostructure layer 2 is carbon nanomaterials. Carbon nanomaterials, such as carbon nanotubes or carbon nanofibers, have extremely high specific surface areas, excellent mechanical strengths, good thermal conductivities and electrical conductivities. Among them, the high specific surface areas of carbon nanomaterials mean that they can provide more surface sites to interact with the first electrons, thereby enhancing the electron scattering and capture capabilities, further helping to reduce the aggregation of electrons near the bombardment surface 11, reducing the risk of arc discharge, and improving the X-ray generation efficiency.

[0090] Furthermore, carbon nanomaterials have excellent mechanical strengths and can withstand the high temperature and high pressure generated by electron beam bombardment. Thus, the first nanostructure layer 2 can maintain structural stability under harsh working conditions and extend the service life of the anode assembly 10.

[0091] Furthermore, carbon nanomaterials also have good electrical conductivities and can quickly conduct the captured electrons into the anode circuit. Therefore, the anode current increases, the tube current also increases accordingly, and the electric field between the anode assembly 10 and the cathode assembly 20 is stronger, which is beneficial to improving the electron emission efficiency of the filament 5.

[0092] In some embodiments, in combination with Figure 1 , Figure 3 and Figure 4 , the cathode assembly 20 includes: a cathode head 4 for cooperating with the anode target 1 to generate a high-voltage electric field; a filament 5 for emitting an electron beam along a first direction D1 under the action of the high-voltage electric field; a second nanostructure layer 6 covering at least the end face of the cathode head 4 facing the anode assembly 10 and exposing the filament 5, and the second nanostructure layer 6 is used to absorb the second electrons generated by the cathode head 4.

[0093] Specifically, the cathode head 4 can cooperate with the anode target 1 to generate a high-voltage electric field. The high-voltage electric field is the power source for driving electrons to move from the cathode assembly 20 to the anode assembly 10.

[0094] Furthermore, the filament 5 is an electron emission source in the cathode assembly 20. In some embodiments, the filament 5 can be made of a metal such as tungsten. The filament 5 is heated to a high temperature state to generate electrons, and under the action of the high-voltage electric field, the electrons form an electron beam. The electron beam moves at a high speed along the first direction D1 and finally bombards the anode target 1 to generate X-rays.

[0095] Furthermore, a second nanostructure layer 6 is covered on the end face of the cathode head 4 facing the anode assembly 10. The second nanostructure layer 6 is used to absorb the second electrons generated by the cathode head 4. During the operation of the X-ray tube 100, the cathode head 4 may generate some secondary electrons (i.e., second electrons) due to various reasons (such as electric field action, thermal radiation, etc.). If these electrons escape randomly, it may have a negative impact on the performance of the X-ray tube 100.

[0096] In some embodiments, the second nanostructure layer 6 can also cover the side surface of the cathode head 4. Thus, under the action of the high-voltage electric field, the redundant electrons generated on the side surface of the cathode head 4 are also absorbed, avoiding the formation of an electron cloud near the cathode head 4, interfering with the emission of the electron beam or increasing the discharge risk.

[0097] In some embodiments, the second electrons include the redundant electrons generated by the cathode head 4.

[0098] In practical applications, as described above, the electron beam is generated by the filament 5 and emitted under the action of a high-voltage electric field. However, it should be noted that under the action of the high-voltage electric field, the cathode head 4 (usually made of a metal material) also releases some electrons. These electrons do not come from the emission of the filament 5, but are generated due to the physical effects of the cathode head 4 in the electric field (such as field emission, thermionic emission, etc.). These electrons released by the cathode head 4 are the redundant electrons. Further, the redundant electrons are likely to form an electron cloud near the cathode head 4, which may interfere with the effective electron beam emitted by the filament 5, resulting in a decrease in the focusing and stability of the electron beam, and further affecting the generation efficiency and quality of X-rays. In addition, the electron cloud formed by the aggregation of redundant electrons also has the risk of arc discharge, which may cause faults and damages to the X-ray tube 100.

[0099] In some embodiments, referring to Figure 4 , along the first direction D1, the projection of the second nanostructure layer 6 and the projection of the filament 5 do not overlap. In other words, the second nanostructure layer 6 avoids the emission trajectory of the electron beam emitted by the filament 5 to prevent the second nanostructure layer 6 from interfering with the electron beam.

[0100] In some embodiments, the second nanostructure layer 6 includes: a second nanotube layer 61, which is attached to the end face of the cathode head 4 facing the anode assembly 10, and the second nanotube layer 61 includes a plurality of second nanotubes 611 extending along the first direction D1.

[0101] In some embodiments, the diameters of the plurality of second nanotubes 611 are the same or the diameter of at least one of the second nanotubes 611 is different from the diameters of the other second nanotubes 611.

[0102] In some embodiments, the diameter of each second nanotube 611 is in the range of [0.5, 5] nanometers.

[0103] In some embodiments, the end faces of the plurality of second nanotubes 611 facing the anode assembly 10 are flush.

[0104] In some embodiments, the gap between adjacent second nanotubes 611 is less than 2 nanometers.

[0105] In some embodiments, after the second electrons generated by the cathode head 4 enter the second nanotubes 611, they are reflected or absorbed between the inner walls of the second nanotubes 611.

[0106] It should be understood that the structural parameters, working principles, and beneficial effects of the second nanotube layer 61 can be the same as those of the first nanotube layer 21. Therefore, for the structural parameters, working principles, and beneficial effects of the second nanotube layer 61, reference can be made to the relevant descriptions of the first nanotube layer 21 above, and details are not described here.

[0107] In some embodiments, the second nanostructure layer 6 further includes: a nanofiber layer 62 covering a side of the second nanotube layer 61 away from the cathode head 4, and the nanofiber layer 62 is configured to absorb the second electrons in the second nanotubes 611.

[0108] Specifically, in addition to the second nanotube layer 61, the second nanostructure layer 6 may further include a nanofiber layer 62. The nanofiber layer 62 is covered on a side of the second nanotube layer 61 away from the cathode head 4 to absorb the second electrons that may escape from the second nanotubes 611. Since the nanofiber layer 62 has an extremely high specific surface area and excellent electron capture ability, it can effectively capture and fix these second electrons, preventing them from having a negative impact on the performance of the X-ray tube 100. Thus, the combination of the nanofiber layer 62 and the second nanotube layer 61 forms a multi-layer electron capture system, further improving the absorption and capture efficiency of the second nanostructure layer 6 for the second electrons.

[0109] In some embodiments, the second nanotube layer 61 and the nanofiber layer 62 may be connected by physical adsorption and winding. For example, due to its extremely small diameter and large specific surface area, the nanofiber has a strong adsorption ability. During the preparation process, the nanofiber layer 62 can naturally adsorb on the surface of the second nanotube layer 61 and intertwine with the nanotubes by physical winding to form a stable structure.

[0110] In some embodiments, the second nanotube layer 61 and the nanofiber layer 62 may also be connected by chemical bonding. For example, by surface modification or introduction of specific functional groups, covalent bonds or other types of chemical bonds are formed between the second nanotube layer 61 and the nanofiber layer 62.

[0111] In some embodiments, the nanofiber layer 62 includes a plurality of sub-fiber layers 621 stacked, and the number of layers of the sub-fiber layer 621 ranges from [5, 10] layers.

[0112] Specifically, the nanofiber layer 62 is composed of a plurality of sub-fiber layers 621 stacked. Thereby, the overall thickness and specific surface area of the nanofiber layer 62 can be increased, thus providing more electron capture sites.

[0113] Furthermore, the number of layers of the sub-fiber layer 621 ranges from [5, 10] layers. This range is determined according to the nanofiber preparation technology, electron capture efficiency, and the actual application requirements of the X-ray tube 100. Too few layers may not provide sufficient electron capture ability, while too many layers may increase the preparation difficulty and cost.

[0114] In some embodiments, the thickness of the nanofiber layer 62 in the first direction D1 ranges from [30, 50] nanometers. Thus, an appropriate thickness can ensure that the nanofiber layer 62 has sufficient electron capture ability, while not excessively increasing the volume and weight of the X-ray tube 100.

[0115] In some embodiments, the second nanostructure layer 6 is a carbon nanostructure layer.

[0116] In some embodiments, the end face of the cathode head 4 facing the anode assembly 10 is perpendicular to the first direction D1.

[0117] Thus, by adopting the anode assembly 10 and the X-ray tube 100 according to the technical solution of the present application, by providing the first nanostructure layer 2 on the bombardment surface 11 of the anode target 1 to absorb the first electrons at the bombardment surface 11, the aggregation of electrons near the anode assembly 10 can be reduced, effectively avoiding the occurrence of arc discharge when the electron aggregation reaches a certain degree, thereby preventing the X-ray tube 100 from being damaged by arc discharge and extending the service life of the X-ray tube 100.

[0118] Furthermore, the first electrons include reflected electrons and secondary electrons. Absorbing the reflected electrons and secondary electrons can more precisely reduce the arc discharge problems that may be caused by the aggregation of these electrons, thereby better protecting the X-ray tube 100 and extending its service life. In addition, it can also prevent the first electrons aggregated near the anode assembly 10 from forming an electron cloud and colliding with the electrons in the electron beam, affecting the working efficiency of the X-ray tube 100.

[0119] Furthermore, the first nanotube layer 21 is attached to the bombardment surface 11, and multiple first nanotubes 211 thereof extend along the electron beam bombardment direction and have a non-zero angle with the normal of the bombardment surface 11. This structure is beneficial to capturing the first electrons generated at the bombardment surface 11, enabling the reflected electrons in the first electrons to directly shoot towards the inner wall of the first nanotube 211, thereby more effectively absorbing electrons, reducing electron aggregation, reducing the risk of arc discharge, and extending the life of the X-ray tube 100.

[0120] Furthermore, multiple layers of the first nanotube layer 21 are stacked along the first direction. Since the tube walls of the first nanotubes 211 are relatively thin, the electron beam can still pass through the internal channels of the first nanotubes 211 and the gaps between adjacent first nanotubes 211. And the first electrons can bounce multiple times between the inner walls of the first nanotubes 211, increasing the ability of the first nanostructure layer 2 to absorb the first electrons and being able to capture more electrons.

[0121] The X-ray tube 100 includes an anode assembly 10 having a first nanostructured layer 2 and a cathode assembly 20 having a second nanostructured layer 6, which absorb electrons from the anode and cathode sides respectively, comprehensively reducing the accumulation of electrons within the X-ray tube 100, effectively reducing the risk of arc discharge, protecting the X-ray tube 100, and extending its service life.

[0122] Further, the second electrons are redundant electrons generated by the cathode head 4. Absorbing and processing these redundant electrons can reduce the accumulation of electrons near the cathode assembly 20, reduce the possibility of arc discharge caused by electron accumulation, protect the X-ray tube 100, and extend its service life.

[0123] It should be understood that the term "and / or" in this article is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article indicates that the associated objects before and after are in an "or" relationship. As used herein, unless otherwise clearly stated, the term "or" covers all possible combinations, unless infeasible. For example, if it is stated that a component can include A or B, then unless otherwise clearly stated or infeasible, the component can include A, or B, or A and B. As a second example, if it is stated that a component can include A, B, or C, then unless otherwise clearly stated or infeasible, the component can include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C. "Multiple" as used in the embodiments of this application means two or more.

[0124] In the embodiments of this application, relational terms such as first, second, etc. are only used to distinguish an entity or operation from another entity or operation, and do not require or imply any actual relationship or order between these entities or operations. In addition, words such as "include", "have", and "contain" and other similar forms are intended to be equivalent in meaning and are open-ended. One or more items following any of these words do not mean an exhaustive list of such one or more items, nor are they limited to the listed one or more items. In the drawings and the specification, exemplary embodiments have been disclosed. However, many variations and modifications can be made to these embodiments. Therefore, although specific terms are used, they are only for general and descriptive purposes and not for the purpose of limitation.

[0125] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be subject to the scope defined by the claims.

Claims

1. An anode assembly for an X-ray tube, characterized in that: include: an anode target having a bombardment surface, wherein the bombardment surface is used to receive an electron beam emitted along a first direction to generate X-rays; A first nanostructure layer at least covers the bombardment surface, wherein the first nanostructure layer is used to absorb first electrons at the bombardment surface; The first nanostructure layer comprises: At least one first nanotube layer is attached to the bombardment surface, the first nanotube layer includes a plurality of first nanotubes extending along the first direction, the first direction is parallel to the bombardment direction of the electron beam, and there is a non-zero angle between the first direction and the normal of the bombardment surface.

2. The anode assembly according to claim 1, characterized in that The first electrons include at least one of reflected electrons and excited secondary electrons generated when the electron beam bombards the bombardment surface.

3. The anode assembly according to claim 1, characterized in that: The first nanostructure layer includes multiple layers of the first nanotube layers, and the multiple layers of the first nanotube layers are stacked and laid along the first direction.

4. The anode assembly according to claim 1, characterized in that The plurality of first nanotubes in each of the first nanotube layers are distributed on a plane parallel to the bombardment surface.

5. The anode assembly according to claim 1, characterized in that: The diameters of the plurality of first nanotubes are the same or the diameter of at least one of the first nanotubes is different from the diameters of the other first nanotubes; and / or The diameter of each of the first nanotubes is in the range of [0.5, 5] nanometers; and / or End surfaces of the plurality of first nanotubes facing the first direction are flush; and / or The gap between adjacent first nanotubes is less than 2 nanometers.

6. The anode assembly according to claim 1, characterized in that: Each of the first nanotubes has an opening along the first direction toward a side away from the anode target. Electrons in the electron beam enter the first nanotube from the opening and generate the first electrons after bombarding the bombardment surface. The first electrons are reflected or absorbed between the inner walls of the first nanotube.

7. The anode assembly according to claim 1, characterized in that The length of each of the first nanotubes in the plurality of first nanotubes along the first direction is within the range of [50, 100] nanometers.

8. The anode assembly according to claim 1, characterized in that Also includes: The heat storage structure is arranged on the other side of the anode target where the bombardment surface is formed, and the first nanostructure layer extends from the bombardment surface to the heat storage structure.

9. The anode assembly according to claim 1, characterized in that: The material of the first nanostructure layer is carbon nanotubes.

10. An X-ray tube, characterized in that: include: The anode assembly according to any one of claims 1 to 9; A cathode assembly comprising: A cathode head, used to cooperate with the anode target to generate a high voltage electric field; A filament, used for emitting an electron beam under the action of the high voltage electric field; The second nanostructure layer at least covers the end surface of the cathode head facing the anode assembly and exposes the filament, and the second nanostructure layer is used to absorb the second electrons generated by the cathode head.

11. The X-ray tube according to claim 10, characterized in that The second electrons include redundant electrons generated by the cathode head and not forming the electron beam.

12. The X-ray tube according to claim 10, characterized in that Along the first direction, a projection of the second nanostructure layer and a projection of the filament do not overlap.

13. The X-ray tube according to claim 10, characterized in that The second nanostructure layer comprises: The second nanotube layer is attached to the end surface of the cathode head facing the anode assembly, and the second nanotube layer includes a plurality of second nanotubes extending along the first direction.

14. The X-ray tube according to claim 13, characterized in that The diameters of the plurality of second nanotubes are the same or the diameter of at least one of the second nanotubes is different from the diameters of the other second nanotubes; and / or The diameter of each of the second nanotubes is in the range of [0.5, 5] nanometers; and / or The end surfaces of the plurality of second nanotubes facing the anode assembly are flush; and / or The gap between adjacent second nanotubes is less than 2 nanometers.

15. The X-ray tube according to claim 13, characterized in that After the second electrons generated by the cathode head enter the second nanotube, they are reflected or absorbed between the inner walls of the second nanotube.

16. The X-ray tube according to claim 13, characterized in that The second nanostructure layer further comprises: The nanofiber layer covers a side of the second nanotube layer away from the cathode head, and the nanofiber layer is used for absorbing the second electrons in the second nanotube.

17. The X-ray tube according to claim 16, characterized in that The nanofiber layer comprises a plurality of stacked sub-fiber layers, wherein the number of layers of the sub-fiber layers is in the range of [5, 10] layers; and / or The thickness of the nanofiber layer along the first direction is in the range of [30, 50] nanometers.

18. The X-ray tube according to claim 10, characterized in that The second nanostructure layer is a carbon nanolayer structure; and / or An end surface of the cathode head facing the anode assembly is perpendicular to the first direction.

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