Anode assembly for x-ray tube and x-ray tube

Abstract

An anode assembly for an X-ray tube and an X-ray tube wherein the anode assembly for an X-ray tube comprises: an anode target having a bombardment surface for receiving an electron beam emitted in a first direction to generate an X-ray; and the first nano-structure layer at least covers the bombardment surface, and the first nano-structure layer is used for absorbing the first electrons on the bombardment surface. According to the technical scheme, the service life of the X-ray tube can be prolonged, and the working efficiency of the X-ray tube is 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 the X-ray tube. Background Art

[0002] The X-ray tube is the core component of the CT system, which mainly consists of two parts: the cathode and the anode. During the operation of the X-ray tube, current is loaded on 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 to generate X-rays.

[0003] However, during the operation of existing X-ray tubes, a large number of electrons will gather near the cathode assembly and the anode assembly. These electrons include electrons emitted by the filament, electron clouds formed near the cathode due to the electric field, and electrons reflected after the electrons hit the anode target plate and excited secondary electrons. When the electrons gather near the cathode assembly and the anode assembly to a certain extent, arc discharge will occur, which will damage the X-ray tube or reduce the life of the X-ray tube. Summary of the invention

[0004] The technical problem solved by the present invention is how to prolong 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, comprising: 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; and a first nanostructure layer, at least covering the bombardment surface, wherein the first nanostructure layer is used to absorb first electrons at the bombardment surface.

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

[0007] Optionally, the first nanostructure layer includes: at least one first nanotube layer, which is attached to the bombardment surface, the first nanotube layer includes multiple 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.

[0008] Optionally, 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.

[0009] Optionally, the plurality of first nanotubes in each first nanotube layer are distributed on 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 the plurality of second nanotubes are the same or the diameter of at least one second nanotube is different from the diameters of the other second nanotubes.

[0023] Optionally, the diameter of each of the second nanotubes is within the range of [0.5, 5] nanometers.

[0024] Optionally, end surfaces of the plurality of 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 nanotube, they are reflected or absorbed between inner walls of the second nanotube.

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

[0028] Optionally, the nanofiber layer includes a plurality of stacked sub-fiber layers, and the number of layers of the sub-fiber layers is [5, 10].

[0029] Optionally, the thickness of the nanofiber layer along the first direction is in the range of [30, 50] nanometers.

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

[0031] Optionally, an end surface 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] An embodiment of the present invention provides an anode assembly for an X-ray tube, comprising: 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; and a first nanostructure layer, at least covering the bombardment surface, wherein the first nanostructure layer is used to absorb first electrons at the bombardment surface.

[0034] By adopting the technical solution of the present application, a first nanostructure layer is provided on the bombardment surface of the anode target to absorb the first electrons on the bombardment surface, thereby reducing the aggregation of electrons near the anode assembly, effectively avoiding arc discharge when the electron aggregation reaches a certain level, thereby preventing arc discharge from damaging the X-ray tube and extending the service life of the X-ray tube.

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

[0036] Furthermore, a first nanotube layer including a plurality of first nanotubes is attached to the bombardment surface, and the plurality of first nanotubes extend along the bombardment direction of the electron beam and have a non-zero angle with the normal of the bombardment surface. This structure is conducive to capturing the first electrons generated at the bombardment surface, so that the reflected electrons among the first electrons are directly shot to the inner wall of the first nanotube, thereby more effectively absorbing electrons, reducing electron aggregation, reducing the risk of arc discharge, and extending the life of the X-ray tube.

[0037] Furthermore, multiple first nanotube layers are stacked and laid along the first direction. Since the walls of the first nanotubes are relatively thin, the electron beam can still pass through the internal channels of the first nanotubes and the gaps between adjacent first nanotubes. 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 capture more electrons.

[0038] An embodiment of the present invention also 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 surface 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.

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

[0040] Furthermore, the second electrons are redundant electrons generated by the cathode head. Absorption processing is performed on these redundant electrons, which can reduce the aggregation of electrons near the cathode assembly, reduce the possibility of arc discharge caused by electron aggregation, protect the X-ray tube, and extend its service life. BRIEF 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 yes Figure 1A partial enlarged view of the middle area A;

[0043] Figure 3 yes Figure 1 A partial enlarged view of the middle area B;

[0044] Figure 4 yes Figure 1 Schematic diagram of the cathode head. DETAILED DESCRIPTION

[0045] As mentioned in the background technology, during the operation of the existing X-ray tube, a large number of electrons will gather near the cathode assembly and the anode assembly, which may easily cause arc discharge, resulting in damage to the X-ray tube or shortening the life of the X-ray tube. In addition, the electron cloud formed by the electron aggregation 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, comprising: 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; and a first nanostructure layer, at least covering the bombardment surface, wherein the first nanostructure layer is used to absorb first electrons at the bombardment surface.

[0047] By adopting the technical solution of the present application, a first nanostructure layer is provided on the bombardment surface of the anode target to absorb the first electrons at the bombardment surface, thereby reducing the aggregation of electrons near the anode assembly, effectively avoiding arc discharge when the electron aggregation reaches a certain level, thereby preventing arc discharge from damaging the X-ray tube and extending the service life of the X-ray tube.

[0048] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below 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 yes Figure 1 A partial enlarged view of area A in the middle.

[0050] refer to Figure 1 The X-ray tube 100 may include an anode assembly 10 and a cathode assembly 20. The cathode assembly 20 is used to emit electron beams to the anode assembly, and the electron beams bombard the anode assembly 10 to form X-rays.

[0051] Specifically, the X-ray tube 100 (also called an X-ray tube, a CT tube) can be used in X-ray machines in the medical field, such as disease detection instruments such as CT machines. With the development of technology, CT machines have been popularized due to their high resolution and intuitive and accurate diagnostic effects, and have been widely used in the medical field. The X-ray tube 100 can be used as a core component in a CT machine, and is widely used in practice to generate X-rays. Therefore, whether the technology of the X-ray tube 100 is perfect directly affects the working effect of the CT machine.

[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 emit may be provided on the housing 101.

[0053] Furthermore, in the X-ray tube 100, the principle of generating X-rays is that the filament 5 in the cathode assembly 20 generates heat to generate electrons, and a large number of electrons are accelerated by the high-voltage electric field between the cathode assembly 20 and the anode assembly 10 to bombard the anode assembly 10 to generate X-rays. The X-rays are filtered and emitted by the electron emission window 102, and are received by the CT detector for imaging after passing through the patient. The process of electron bombardment of the anode assembly 10 will generate a large amount of heat. If the bombardment position remains unchanged, the bombarded area of ​​the anode assembly 10 will generate a large amount of heat, and the heat generation rate is much greater than its heat dissipation rate. When the heat accumulates to a critical value, the bombarded area of ​​the target surface is melted, causing the anode to fail. Therefore, the X-ray tube in the prior art generally adopts a rotating anode, 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 continues to change, avoiding the phenomenon of local temperature increase damaging the anode assembly 10.

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

[0055] Specifically, the anode target 1 is used to receive the 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 the electron beam emitted along the first direction D1. When high-speed electrons in the electron beam bombard the bombardment surface 11, they interact with the material of the anode target 1, thereby generating X-rays.

[0057] In some embodiments, the anode target 1 may be in a high-speed rotating state during operation to prevent heat from being concentrated in a fixed area of ​​the anode target 1, causing a temperature rise or even melting the target surface. In this scenario, the bombardment surface 11 may 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, the bombardment surface 11 is covered with a first nanostructure layer 2. 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, namely, first electrons, will gather at the bombardment surface 11. If the first electrons are not effectively processed, they may cause arc discharge and other phenomena, 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 gathering of electrons at the bombardment surface 11 and avoiding the occurrence of adverse phenomena such as arc discharge.

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

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

[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 from the bombardment surface 11. If the reflected electrons are not effectively processed, they may gather near the anode assembly 10, causing arc discharge and other phenomena, causing damage to the X-ray tube 100. There is even the possibility of colliding with other electrons in the electron beam, hindering the normal injection of the electron beam, resulting in a decrease in the efficiency of X-ray generation.

[0063] In addition, when the electron beam bombards the bombardment surface 11, in addition to possibly generating reflected electrons, it may also excite electrons in the anode target 1 material, causing it to escape from the material surface to form secondary electrons. These secondary electrons will also gather 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 also 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 other physical processes (such as thermal electron emission, field emission, etc.) to generate electrons at the bombardment surface 11. These electrons can also be effectively absorbed by the first nanostructure layer 2 to reduce the risk of electron aggregation and arc discharge.

[0065] In some embodiments, the first nanostructure layer 2 may include: at least one first nanotube layer 21, which is attached to the bombardment surface 11, and the first nanotube layer 21 includes a plurality of first nanotubes 211 extending along the first direction D1, and the first direction D1 is parallel to the bombardment direction of the electron beam, and there is 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 , thereby being able to more effectively capture the first electrons generated at the bombardment surface 11 .

[0067] Furthermore, the first nanotubes 211 extend along a first direction D1, which is parallel to the bombardment direction of the electron beam. Thus, the electron beam can pass through the inner channel of the first nanotubes 211 and the gaps between adjacent nanotubes 211 to reach the bombardment surface 11. The first nanotubes 211 will not affect the normal injection 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. Therefore, after leaving the bombardment surface 11, the reflected electrons can directly shoot toward the inner wall of the first nanotube 211, increasing the collision probability between the reflected electrons and the inner wall of the first nanotube 211, thereby more effectively absorbing the electrons.

[0069] As described above, since the first nanotube 211 extends along the electron beam bombardment direction and has an angle with the normal of the bombardment surface 11, the reflected electrons are more easily captured by the nanotube. When the reflected electrons are emitted to the inner wall of the first nanotube 211, they will be absorbed or scattered by the material of the first nanotube 211, thereby reducing the aggregation near the bombardment surface 11.

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

[0071] In some embodiments, the plurality of first nanotubes 211 in the first nanotube layer 21 may attract each other through interaction forces such as van der Waals force, hydrogen bonding, or electrostatic interaction.

[0072] In some embodiments, the plurality of first nanotubes 211 may further form hydrogen bonds, be physically entangled or interwoven to increase the tightness of connection, thereby enhancing the mechanical strength and stability of the first nanotube layer 21 .

[0073] In some embodiments, the first nanostructure layer 2 includes multiple first nanotube layers 21 , which are stacked along the first direction D1 , thereby forming a more dense and complex structure on the bombardment surface 11 .

[0074] Furthermore, since the wall of the first nanotube 211 is relatively thin, the electron beam can still pass through the internal channel of the first nanotube 211 and the gaps between adjacent first nanotubes 211 when passing through the first nanostructure layer 2, which ensures that the electron beam can normally bombard the bombardment surface 11 and 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 chances of the first electrons contacting 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 stacking of multiple first nanotube layers 21 enables the first nanostructure layer 2 to have more inner walls of the first nanotubes 211 , thereby providing more collision and capture opportunities for the first electrons.

[0077] In some embodiments, multiple first nanotube layers 21 may be stacked in an interlaced manner, that is, the first nanotubes 211 of two adjacent first nanotube layers 21 are not in a one-to-one correspondence, but are offset to a certain extent. Thus, a more intricate network structure can be formed between the first nanotubes 211, increasing the contact points and cross regions between the first nanotubes 211, and providing more scattering and capture paths for the first electrons.

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

[0079] In some embodiments, the diameters of the plurality of 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 an area where the density and number of first electrons are higher, the diameter of the first nanotube 211 can be set to be relatively small, so that more first nanotubes 211 can be arranged in the area, thereby improving the capture efficiency of the first electrons.

[0080] In some embodiments, the diameter of each of the first nanotubes 211 is selected from [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 capture efficiency of the first electrons. A larger diameter (such as 5 nanometers) can reduce the wall thickness of the first nanotube 211, thereby avoiding affecting the injection of the electron beam. Therefore, by selecting a suitable diameter, the electron scattering and capture ability of the first nanostructure layer 2 can be optimized.

[0081] In some embodiments, the end surfaces of the plurality of first nanotubes 211 facing the first direction D1 are flush, thereby ensuring that the nanotube layer forms a flat surface on the bombardment surface 11, which is conducive to uniform bombardment of the electron beam and stable generation of X-rays.

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

[0083] In some embodiments, each of the first nanotubes 211 has an opening along the first direction D1 toward a side away from the anode target 1. 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 first nanotubes 211 along the first direction D1 is in the range of [50, 100] nanometers, thereby ensuring that the first nanotubes 211 have sufficient length to effectively scatter and capture electrons, while not increasing the difficulty of preparation or reducing 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 arranged 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 of the anode target 1 and the first nanostructure layer 2 stable. In this way, it is possible to avoid the anode target 1 from being damaged by being overheated.

[0087] Furthermore, the first nanostructure layer 2 extends from the bombardment surface 11 to the heat storage structure 3. Thus, it can be ensured 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 nano. Carbon nanomaterials, such as carbon nanotubes or carbon nanofibers, have extremely high specific surface area, excellent mechanical strength, good thermal conductivity and electrical conductivity. Among them, the high specific surface area of ​​carbon nanomaterials means that they can provide more surface sites to interact with the first electrons, thereby enhancing the scattering and capture capabilities of the electrons, thereby helping to reduce the aggregation of electrons near the bombardment surface 11, reduce the risk of arc discharge, and improve the efficiency of X-ray generation.

[0090] Furthermore, the carbon nanomaterial has excellent mechanical strength and can withstand the high temperature and high pressure generated by electron beam bombardment, thereby enabling the first nanostructure layer 2 to maintain structural stability in harsh working environments and prolonging the service life of the anode assembly 10.

[0091] Furthermore, the carbon nanomaterial also has good electrical conductivity and can quickly introduce the captured electrons into the anode circuit. Therefore, the anode current will increase, the tube current will increase accordingly, and the electric field between the anode assembly 10 and the cathode assembly 20 will also be stronger, which is beneficial to improving the electron emission efficiency of the filament 5.

[0092] In some embodiments, in combination Figure 1 , Figure 3 and Figure 4 The cathode assembly 20 includes: a cathode head 4, used to cooperate with the anode target 1 to generate a high-voltage electric field; a filament 5, used to emit an electron beam along a first direction D1 under the action of the high-voltage electric field; a second nanostructure layer 6, at least covering the end surface 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 a power source for driving electrons to move from the cathode assembly 20 to the anode assembly 10.

[0094] Further, the filament 5 is an electron emission source in the cathode assembly 20. In some embodiments, the filament 5 can be made of metal such as tungsten. The filament 5 is heated to a high temperature 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, the end surface of the cathode head 4 facing the anode assembly 10 is covered with a second nanostructure layer 6. 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 effect, thermal radiation, etc.). If these electrons escape at will, they may have a negative impact on the performance of the X-ray tube 100.

[0096] In some embodiments, the second nanostructure layer 6 may 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 will also be absorbed, avoiding the formation of an electron cloud near the cathode head 4, interfering with the emission of the electron beam or increasing the risk of discharge.

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

[0098] In practical applications, as mentioned above, the electron beam is generated by the filament 5 and emitted under the action of a high-voltage electric field. However, it is worth noting that under the action of a high-voltage electric field, the cathode head 4 (usually made of a metal material) will also release some electrons. These electrons do not come from the emission of the filament 5, but are generated by the physical effects of the cathode head 4 in the electric field (such as electric field emission, thermal emission, etc.). These electrons released by the cathode head 4 are the redundant electrons. Furthermore, the redundant electrons gather near the cathode head 4 to easily form an electron cloud, 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, thereby affecting the efficiency and quality of the generation 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 failure and damage to the X-ray tube 100.

[0099] In some embodiments, reference Figure 4 , along the first direction D1, the projection of the second nanostructure layer 6 does not overlap with the projection of the filament 5. 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 surface 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 second nanotube 611 is different from the diameters of the other second nanotubes 611 .

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

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

[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 nanotube 611 , they are reflected or absorbed between the inner walls of the second nanotube 611 .

[0106] It should be understood that the structural parameters, working principle and beneficial effects of the second nanotube layer 61 can be the same as those of the first nanotube layer 21. Therefore, the structural parameters, working principle and beneficial effects of the second nanotube layer 61 can refer to the above description of the first nanotube layer 21, which will not be repeated 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 used to absorb the second electrons in the second nanotube 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 the side of the second nanotube layer 61 away from the cathode head 4 to absorb the second electrons that may escape from the second nanotube 611. Since the nanofiber layer 62 has an extremely high specific surface area and excellent electron capture capability, it can effectively capture and fix these second electrons to prevent 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-level 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 can be connected by physical adsorption and entanglement. For example, nanofibers have strong adsorption capacity due to their extremely small diameter and large specific surface area. During the preparation process, the nanofiber layer 62 can be naturally adsorbed on the surface of the second nanotube layer 61, and intertwined with the nanotubes by physical entanglement 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 to form covalent bonds or other types of chemical bonds between the second nanotube layer 61 and the nanofiber layer 62 .

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

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

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

[0114] In some embodiments, the thickness of the nanofiber layer 62 along the first direction D1 is between [30, 50] nanometers. Thus, a suitable thickness can ensure that the nanofiber layer 62 has sufficient electron capture capability without excessively increasing the volume and weight of the X-ray tube 100.

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

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

[0117] As described above, by adopting the anode assembly 10 for an X-ray tube 100 and the X-ray tube 100 described in the technical solution of the present application, by arranging 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, and arc discharge can be effectively avoided when the electron aggregation reaches a certain level, thereby preventing the arc discharge from damaging the X-ray tube 100 and extending the service life of the X-ray tube 100.

[0118] Furthermore, the first electrons include reflected electrons and secondary electrons, and absorbing the reflected electrons and secondary electrons can more accurately reduce 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 gathered near the anode assembly 10 from forming an electron cloud that collides with 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 its multiple first nanotubes 211 extend along the electron beam bombardment direction and have a non-zero angle with the normal of the bombardment surface 11. This structure is conducive to capturing the first electrons generated at the bombardment surface 11, so that the reflected electrons among the first electrons are directly emitted to 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, the multiple first nanotube layers 21 are stacked and laid along the first direction, and since the 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. 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 capturing more electrons.

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

[0122] Furthermore, the second electrons are redundant electrons generated by the cathode head 4. Absorption processing is performed on these redundant electrons, which can reduce the aggregation of electrons near the cathode assembly 20, reduce the possibility of arc discharge caused by electron aggregation, protect the X-ray tube 100, and extend its service life.

[0123] It should be understood that the term "and / or" herein is merely an association relationship describing associated objects, indicating that three relationships may exist, for example, A and / or B, which may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " herein indicates that the associated objects before and after are in an "or" relationship. As used herein, unless otherwise expressly stated, the term "or" covers all possible combinations unless it is not feasible. For example, if a component is stated to include A or B, then unless otherwise expressly stated or not feasible, the component may include A, or B, or A and B. As a second example, if a component is stated to include A, B, or C, then unless otherwise expressly stated or not feasible, the component may include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C. The "multiple" appearing in the embodiments of the present application refers to two or more.

[0124] The relational terms appearing in the embodiments of the present application, 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, the words "include", "have" and "comprise" and other similar forms are intended to be equivalent in meaning, and are open-ended, and one or more items behind any of these words are not meant to be an exhaustive list of such one or more items, or mean to be limited to one or more items listed. In the accompanying drawings and the specification, exemplary embodiments have been disclosed. However, many changes and modifications can be made to these embodiments. Therefore, although specific terms have been adopted, they are only used in a general and descriptive sense, 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 shall 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; The first nanostructure layer at least covers the bombardment surface, and the first nanostructure layer is used for absorbing the first electrons at 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 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.

4. The anode assembly according to claim 3, 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.

5. The anode assembly according to claim 3, 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.

6. The anode assembly according to claim 3, 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.

7. The anode assembly according to claim 3, 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.

8. The anode assembly according to claim 3, 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.

9. 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.

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

11. An X-ray tube, characterized in that: include: The anode assembly according to any one of claims 1 to 10; 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.

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

13. The X-ray tube according to claim 11, characterized in that Along the first direction, a projection of the second nanostructure layer and a projection of the filament do not overlap.

14. The X-ray tube according to claim 11, 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.

15. The X-ray tube according to claim 14, 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.

16. The X-ray tube according to claim 14, 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.

17. The X-ray tube according to claim 14, 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.

18. The X-ray tube according to claim 17, 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.

19. The X-ray tube according to claim 11, 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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