X-ray tube

Abstract

This application relates to an X-ray tube. An X-ray tube includes a tube body, an electron source, and an anode target. The tube body has a vacuum chamber. The electron source includes an optical fiber and an electron emission layer. The emitting end of the optical fiber is located within the vacuum chamber. The electron emission layer is disposed at the emitting end of the optical fiber and includes at least an electron excitation layer. The electron excitation layer is positioned along the emission path of the laser emitted from the optical fiber, enabling the electron excitation layer to emit electrons under laser excitation. The anode target is disposed within the vacuum chamber, and is positioned opposite and spaced apart from the emitting end of the optical fiber. The anode target receives electrons emitted from the electron excitation layer to emit X-rays. The tube body has an output window facing the anode target, configured to guide X-rays out of the vacuum chamber. This X-ray tube's electron source enables cold emission of electrons, significantly improving the heat accumulation problem of the anode target.

Description

Technical Field

[0001] This application relates to the field of X-ray tube technology, and in particular to X-ray tubes. Background Technology

[0002] An X-ray tube is a vacuum electronic device that generates X-rays by bombarding a metal target with high-speed electrons. A traditional X-ray tube typically consists of a filament (as the cathode) for emitting electrons and a target (as the anode) for receiving the electron bombardment, both sealed within a high-vacuum glass or ceramic housing. However, in traditional X-ray tubes, the filament, acting as the cathode, operates at a high temperature (up to 2000°C), easily generating thermal radiation to the target, which exacerbates the heat accumulation problem on the target. Summary of the Invention

[0003] Therefore, it is necessary to provide an X-ray tube that addresses the heat accumulation problem of the target material in traditional X-ray tubes.

[0004] This application provides an X-ray tube, comprising:

[0005] The tube body has a vacuum chamber inside;

[0006] An electron source includes an optical fiber and an electron emitting layer. The emitting end of the optical fiber is located within the vacuum chamber. The electron emitting layer is disposed at the emitting end of the optical fiber and includes at least an electron excitation layer. The electron excitation layer is disposed in the light emission path of the laser emitted from the optical fiber, so that the electron excitation layer can emit electrons under the excitation of the laser.

[0007] An anode target is disposed within the vacuum chamber, and the anode target is positioned opposite and spaced apart from the light-emitting end of the optical fiber. The anode target is used to receive electrons emitted from the electron-excited layer in order to emit X-rays.

[0008] The tube body is provided with an output window facing the anode target, and the output window is configured to guide the X-rays out of the vacuum chamber.

[0009] The electron excitation layer includes at least one of zero-dimensional materials, one-dimensional materials, and two-dimensional materials.

[0010] In one embodiment, the electron source and the anode target are spaced apart along the extension direction of the optical fiber;

[0011] The anode target has a reflective target surface facing the light-emitting end, and the reflective target surface is set at an angle to the extension direction of the optical fiber;

[0012] The output window is located on the side wall of the tube and faces the reflective target surface.

[0013] In one embodiment, the anode target includes a transmission anode;

[0014] Along the longitudinal extension direction of the tube, the electron source and the output window are located at opposite ends of the tube, and the transmission anode is located between the electron source and the output window.

[0015] In one embodiment, the anode target is spaced apart from the light-emitting end of the optical fiber along the extension direction of the optical fiber, and a preset electric field exists between the anode target and the electron excitation layer, so that the electrons emitted from the electron excitation layer can be accelerated linearly along the extension direction of the optical fiber.

[0016] In one embodiment, the electron source further includes a conductive connection layer, which is disposed at least at the light-emitting end of the optical fiber and is electrically connected to the electron excitation layer.

[0017] In one embodiment, the tube is respectively fitted onto the optical fiber and the anode target.

[0018] In one embodiment, the tube has a first port communicating with the vacuum chamber;

[0019] The light-emitting end of the optical fiber extends into the vacuum chamber through the first port, and the outer peripheral wall of the optical fiber is sealed to the inner peripheral wall of the first port.

[0020] In one embodiment, the tube body further has a second port disposed opposite to the first port, and the side of the anode target away from the light-emitting end extends out of the vacuum chamber through the second port;

[0021] The outer peripheral wall of the anode target is sealed to the inner peripheral wall of the second port.

[0022] In one embodiment, the X-ray tube further includes an external electrode disposed between the outer peripheral wall of the anode target and the inner peripheral wall of the second port;

[0023] Along the longitudinal extension direction of the tube, one end of the external electrode is located inside the vacuum chamber, and the other end extends out of the vacuum chamber.

[0024] In one embodiment, the optical fiber has an input end disposed opposite to the output end, and the end face of the input end is flush with the plane containing the first port; or

[0025] The light-input end extends out of the vacuum chamber through the first port.

[0026] In one embodiment, the tube body includes an inner tube sleeved on the optical fiber and the anode target, and an outer tube sleeved on the inner tube. The outer tube has an opening through which part of the structure of the inner tube is exposed to form the output window.

[0027] The inner tube is made of an X-ray transmitting material, and the outer tube is made of an X-ray blocking material.

[0028] In one embodiment, the outer diameter of the tube is 125μm-2000μm, and the length of the tube is 3cm-9cm.

[0029] In one embodiment, the optical fiber includes a core for transmitting laser light and a cladding layer wrapped around the core, and the end face of the light-emitting end of the optical fiber is set at an angle to the extension direction of the core.

[0030] The electron emission layer is disposed on the end face of the light-emitting end of the optical fiber, and the electron excitation layer covers the fiber core of the optical fiber. The laser emitted from the fiber core can directly irradiate the electron emission layer, so that the electron excitation layer is excited by the laser emitted from the fiber core and emits electrons.

[0031] In one embodiment, the optical fiber includes a core for transmitting laser light and a cladding layer wrapped around the core;

[0032] The light-emitting end of the optical fiber has a light-leaking notch constructed along the radial direction of the optical fiber;

[0033] The electron emission layer is disposed on the bottom wall surface of the light leakage notch, the bottom wall surface of the light leakage notch is constructed as a plane, and the projection of the electron excitation layer on the bottom wall surface covers the projection of the fiber core on the bottom wall surface;

[0034] The electron excitation layer also extends to the light-emitting end of the optical fiber.

[0035] In one embodiment, the optical fiber includes a perforated optical fiber having a light guide hole;

[0036] The electron excitation layer is at least disposed on the sidewall of the light guide hole and extends along the extension direction of the light guide hole to the light output end of the optical fiber.

[0037] In one embodiment, the optical fiber includes a perforated optical fiber having a light guide hole;

[0038] The electron emission layer is disposed on the end face of the light-emitting end of the perforated optical fiber, and the electron excitation layer covers the end of the light guide hole located on the end face of the light-emitting end.

[0039] The laser emitted from the perforated optical fiber can directly irradiate the electron emission layer, thereby exciting the electron excitation layer and causing it to emit electrons.

[0040] In one embodiment, the optical fiber has a pointed tip at its output end;

[0041] The electron excitation layer covers the surface of the tip of the optical fiber;

[0042] The optical fiber includes a core for transmitting laser light. The laser light emitted from the core can directly irradiate the electron emission layer, thereby exciting the electron excitation layer and causing it to emit electrons.

[0043] In one embodiment, the thickness of the electron-excited layer is less than or equal to 50 nm.

[0044] In the aforementioned X-ray tube, during the transmission of laser light within the fiber core to the output end of the fiber, this laser light interacts with the electron excitation layer. Electrons within the excitation layer absorb the laser photons, undergo energy transitions, and escape from the excitation layer, emitting electrons from the output end. Since the anode target and the output end of the fiber are positioned opposite each other and spaced apart, these electrons can enter the anode target, exciting it to emit X-rays. These X-rays can then exit the vacuum chamber through the output window. Thus, the electron source of this X-ray tube can achieve cold emission of electrons, avoiding the excessive heat generated by hot electrodes like filaments, significantly improving the heat accumulation problem of the anode target. Furthermore, since the electron emission layer is located on the fiber, it saves space within the vacuum chamber, thereby reducing the size of the X-ray tube. Attached Figure Description

[0045] Figure 1 A schematic diagram of the structure of an X-ray tube according to an embodiment of this application is shown.

[0046] Figure 2 It shows Figure 1 An enlarged schematic diagram of point A.

[0047] Figure 3 It shows Figure 1 An enlarged schematic diagram of point B.

[0048] Figure 4 A schematic diagram of the structure of the electronic source according to the first embodiment of this application is shown.

[0049] Figure 5 A schematic diagram of the structure of the electronic source according to the second embodiment of this application is shown.

[0050] Figure 6 It shows Figure 5 Side view.

[0051] Figure 7 A schematic diagram of the structure of the electronic source according to the third embodiment of this application is shown.

[0052] Figure 8 It shows Figure 7 An enlarged schematic diagram of point C.

[0053] Figure 9 A schematic diagram of the structure of the electronic source according to the fourth embodiment of this application is shown.

[0054] Figure 10 It shows Figure 9 An enlarged schematic diagram of point D.

[0055] Figure 11 A schematic diagram of the structure of the electronic source according to the fifth embodiment of this application is shown.

[0056] Figure 12 It shows Figure 11 An enlarged schematic diagram at point E.

[0057] Figure 13 A schematic diagram of the structure of the electronic source according to the sixth embodiment of this application is shown.

[0058] Figure 14 A schematic diagram of the structure of an X-ray tube according to another embodiment of this application is shown.

[0059] Figure 15 It shows Figure 14 An enlarged schematic diagram of point F.

[0060] Figure 16 A schematic diagram of the process for preparing an electron source according to an embodiment of this application is shown.

[0061] Figure label:

[0062] 10. X-ray tube;

[0063] 100, Electron source; 110, Optical fiber; 111, Fiber core; 112, Wrapping layer; 1101, Light input end; 1102, Light output end; 11021, End face; h, Light leakage notch; h1, Bottom wall surface; h2, Side wall surface; k, Side wall of light guide hole; j, Tip; j1, Surface; 120, Electron emission layer; 121, Electron excitation layer; 1211, First part; 1212, Second part; 122, Auxiliary layer; 130, Conductive connection layer; 131, First conductive part; 132, Second conductive part;

[0064] 200, Anode target; 210, Reflective target surface; 220, Transmission anode;

[0065] 300, tube body; 310, inner tube; 311, output window; 320, outer tube; 321, opening; 301, vacuum chamber; 302, first port; 303, second port;

[0066] 400. External electrode;

[0067] 20. Temporary substrate;

[0068] 30. Perforated glass slide;

[0069] 40. Circular heating element. Detailed Implementation

[0070] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0071] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0072] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0073] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0074] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0075] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0076] In traditional technologies, thermionic electron sources primarily utilize metallic materials such as tungsten filaments and lanthanum hexaboride. When heated to thousands of degrees Celsius, electrons are thermally excited and detach from the material surface, forming vacuum electrons. Field emission electron sources mainly employ metal tips such as tungsten, generating a tip discharge effect under the influence of a strong external electric field. Thermionic electron sources can operate in relatively poor vacuum environments, exhibiting good environmental adaptability and stability, but suffer from lower brightness and poor coherence. Field emission electron sources produce electron beams with high brightness and good coherence, but require high vacuum levels and are highly sensitive to vibrations. Both thermionic and field emission electron sources offer limited control over electron emission properties, making it impossible to simultaneously achieve both high performance and stability of the emitted electrons.

[0077] In traditional technologies, light-emitting electron sources use metallic materials such as Au as the electron emission layer, with a thickness exceeding 50 nm, sometimes even reaching hundreds of nanometers. However, the inventors of this application have discovered that the relatively large thickness of the metallic electron emission layer results in a significant distance (50 nm to hundreds of nanometers) between the bottom layer directly interacting with the laser and the surface layer emitting electrons. Electrons excited from the bottom layer are easily affected by scattering from the metal lattice as they pass through the electron emission layer, thus impacting the emission efficiency. Furthermore, metallic materials are prone to damage under high-power laser irradiation, affecting the lifespan of the electron emission layer and consequently impacting the electron emission efficiency and stability.

[0078] In traditional technology, there is another scenario where the light-emitting electron source excites electrons by shining an external laser onto the surface of a metal needle tip. However, the size of the metal needle tip is on the nanometer scale, making it difficult to align the laser spot with the metal needle tip. If a high-magnification microscope is used to align the external laser with the metal needle tip, it will increase the overall cost.

[0079] In addition, traditional technologies use graphene as a saturable absorber. Graphene has broadband saturable absorption characteristics and fast recovery time. It is used in Q-switching and mode-locking of lasers, or in the modulation of laser spectra to achieve sensing and detection.

[0080] Therefore, it is necessary to provide an electron source that can balance electron emission efficiency and stability.

[0081] This application uses low-dimensional materials, such as zero-dimensional, one-dimensional, or two-dimensional materials, as the materials for the electronic excitation layer. Under laser irradiation, low-dimensional materials emit electrons through photoelectric effect, multiphoton emission, and light field emission. Low-dimensional materials have atomic-level thickness, no dangling bonds, and stable properties, thus exhibiting good stability and long service life. Moreover, low-dimensional materials can be directly integrated with optical fibers, which can provide a stable excitation source with adjustable wavelength, polarization, and optical mode, making them suitable for different application scenarios, such as the X-ray tube described below.

[0082] Figure 1 A schematic diagram of the structure of an X-ray tube 10 in one embodiment of this application is shown.

[0083] Please see Figure 1 Please refer to the following: Figure 2 and Figure 3 An embodiment of this application provides an X-ray tube 10, which includes an electron source 100, an anode target 200, and a tube body 300.

[0084] The electron source 100 includes an optical fiber 110 and an electron emitting layer 120. If the optical fiber 110 is a solid optical fiber, it includes a fiber core 111 for transmitting laser light and a cladding layer 112 encasing the fiber core 111. The refractive index of the cladding layer 112 is lower than that of the fiber core 111, thus allowing the laser light to be confined within the fiber core 111 for propagation. A coating layer is also provided on the outer surface of the cladding layer 112 to protect both the cladding layer 112 and the fiber core 111.

[0085] The optical fiber 110 has an input end 1101 and an output end 1102. The input end 1101 is used to couple to a laser source, so that the laser emitted by the laser source can be transmitted through the fiber core 111 of the optical fiber 110. The laser source can be a laser.

[0086] Optical fiber 110 serves as the transmission medium for the laser and the carrier of the low-dimensional material of the electron excitation layer 121. Optical fiber 110 can be a single-mode fiber, multimode fiber, polarization-maintaining fiber, perforated fiber, or multi-core fiber, etc. It should be noted that regardless of the type of optical fiber 110 used, the electron emission layer 120 is located within the vacuum chamber 301.

[0087] The tube body 300 has a vacuum chamber 301. The light-emitting end 1102 of the optical fiber 110 is located inside the vacuum chamber 301. An electron excitation layer 121 is disposed at the light-emitting end 1102 of the optical fiber 110, and the electron emission layer 120 includes at least the electron excitation layer 121. The electron excitation layer 121 is disposed on the light-emitting path of the laser emitted from the optical fiber 110, so that the electron excitation layer 121 can emit electrons under the excitation of the laser. The electron excitation layer 121 includes at least one of zero-dimensional material, one-dimensional material, and two-dimensional material.

[0088] Thus, during the process of the laser transmitted in the core 111 of the optical fiber 110 being emitted from the output end 1102 of the optical fiber 110, this part of the laser can interact with the electron excitation layer 121, causing the electrons in the electron excitation layer 121 to absorb the photons of the laser and undergo energy transition to escape from the electron excitation layer 121, and emit electrons out from the output end 1102.

[0089] It should be noted that the wavelength of the laser can be the wavelength that causes an electron in the electron excitation layer 121 to absorb a photon and transition, for example, the wavelength is in the visible light-near infrared-ultraviolet range, or it can be the wavelength that causes an electron in the electron excitation layer 121 to absorb multiple photons and transition, for example, the wavelength is outside the visible light-near infrared-ultraviolet range, and no specific limitation is made here.

[0090] The anode target 200 is disposed inside the vacuum chamber 301, and the anode target 200 and the light-emitting end 1102 of the optical fiber 110 are opposite to and spaced apart. The anode target 200 is used to receive electrons emitted from the electron excitation layer 121 to emit X-rays. The tube body 300 is provided with an output window 311 facing the anode target 200. The output window 311 is configured to guide X-rays out of the vacuum chamber 301.

[0091] When in use, the X-ray tube 10 can use the electron excitation layer 121 of the electron source 100 to emit electrons toward the anode target 200, which can excite the anode target 200 to emit X-rays. These X-rays can be emitted outside the vacuum chamber 301 through the output window 311. In this way, the electron source 100 of the X-ray tube 10 can achieve cold emission of electrons, which will not generate too much heat like hot electrodes such as filaments. This can significantly improve the heat accumulation problem of the anode target 200. At the same time, since the electron excitation layer 121 is located on the optical fiber 110, it helps to save space in the vacuum chamber 301, thereby helping to reduce the size of the X-ray tube 10.

[0092] The electron source 100 of this application uses low-dimensional materials such as zero-dimensional materials, one-dimensional materials or two-dimensional materials as the material of the electron excitation layer 121, and sets the electron excitation layer 121 on the optical fiber 110 to achieve electron excitation. This eliminates the complex spatial optical coupling structure required by introducing external lasers, and also eliminates the need for a high-magnification microscope to solve the problem of aligning the metal needle tip, thereby reducing the manufacturing cost of the X-ray tube 10.

[0093] Compared to placing a metal layer at the tip of an optical fiber and exciting electrons by direct interaction between the laser transmitted within the fiber and the metal layer (where electrons are easily affected by lattice scattering during their passage through the metal layer, resulting in low electron emission efficiency, wide energy dispersion, and severe heat accumulation), this application uses low-dimensional materials such as zero-dimensional, one-dimensional, or two-dimensional materials as the material for the electron excitation layer 121. Low-dimensional materials have atomic-level thickness, allowing back-incident electrons to be emitted without internal transmission, resulting in high electron emission efficiency. Moreover, low-dimensional materials have no dangling bonds, are stable, have high melting points, and are not easily damaged, making them suitable for high-power excitation scenarios, and possessing characteristics such as good stability and long service life. In addition, low-dimensional materials also have strong light-material interaction and abundant electronic band gaps, enabling the laser to better interact with the electron excitation layer 121 to excite electrons within the electron excitation layer 121. These excited electrons escape into the vacuum, forming an electron beam, and the electron beam tunneling out from within the electron excitation layer 121 has the characteristics of low energy dispersion, high brightness, and high stability.

[0094] Furthermore, low-dimensional materials and optical fibers 110 can be directly integrated. The optical fiber 110 transmits laser light and, as a carrier of low-dimensional materials, can provide a stable excitation source with adjustable wavelength, polarization, and optical mode. It can be applied to different application scenarios without the need for complex optical paths, and features small size and high integration.

[0095] In some embodiments, the thickness of the electron excitation layer 121 is less than or equal to 50 nm.

[0096] It is understandable that the thickness of the electron excitation layer 121 is on the nanometer scale, and the thickness of the electron excitation layer 121 is relatively small. This is more conducive to reducing the process of electrons being transported in the electron excitation layer 121, and is more conducive to improving the electron emission efficiency and emission density. Thus, the electron source 100 can be used to realize an ultrashort pulse electron beam.

[0097] Optionally, the electronic excitation layer 121 may include zero-dimensional materials. Zero-dimensional materials refer to materials whose dimensions are at the nanoscale in the three-dimensional spatial direction, such as nanoparticles, atomic clusters, and quantum dots, and are generally composed of a small number of atoms and molecules. There are many zero-dimensional carbon nanomaterials, such as carbon black, nanodiamonds, diamond color center nanofullerenes. 60 Alternatively, carbon-coated nano-metal particles, etc. Zero-dimensional materials have typical discrete energy levels. Under laser excitation, electrons are mainly excited through tunneling from the discrete energy levels, which makes the electron beam emitted from the electron excitation layer 121 have the characteristics of low energy dispersion, high brightness and high stability.

[0098] Optionally, the electron excitation layer 121 may also include a one-dimensional material. Electrons in the one-dimensional material can be transported along the linear chain of the one-dimensional material. Combined with the fact that the electron excitation layer 121 is located on the light-emitting end 1102 of the optical fiber 110, it is beneficial for the electrons emitted by the electron source 100 to be emitted efficiently along the extension direction of the optical fiber 110. The one-dimensional material has the characteristic of a small radius of curvature (nanometer scale), which can enhance the interaction between light and matter and provide a large field enhancement factor, ensuring multiphoton emission, light field emission, etc., and can be applied to scenarios that require a high-brightness electron source.

[0099] One-dimensional materials can be nanotubes, nanorods or nanowires, nanoribbons or coaxial nanocables, etc.

[0100] Nanotubes can be carbon nanotubes, which can be viewed as seamless tubular structures formed by winding single or multiple layers of graphite according to certain rules. Nanotubes can also be silicon (Si) nanotubes, selenium (Se) nanotubes, tellurium (Te) nanotubes, bismuth (Bi) nanotubes, boron nitride (BN) nanotubes, boron-nitrogen co-doped carbon nanotubes (BCN nanotubes), tungsten sulfide (WS2) nanotubes, molybdenum disulfide (MoS2) nanotubes, or titanium dioxide (TiO2) nanotubes, etc.

[0101] Nanowires can be made of silicon (Si) or germanium (Ge); they can also be oxide nanowires, such as tin oxide (SnO) or zinc oxide (ZnO); of course, they can also be nitride nanowires, such as gallium nitride (GaN) or silicon nitride (Si3N4); they can also be sulfide nanowires, such as cadmium sulfide (CdS) and zinc sulfide (ZnS); and they can also be ternary compound nanowires, such as barium titanate (BaTiO3) and lead titanate (PbTiO3).

[0102] Nanoribbons differ significantly from the two nanostructures mentioned above (nanotubes and nanowires). Their cross-sections are not nearly circular like those of nanotubes or nanowires, but rather quadrilateral, with a width-to-thickness ratio typically ranging from a few to a dozen. Nanoribbons can be made of oxides, such as tin oxide (SnO) or zinc oxide (ZnO).

[0103] Nanocoaxial cables can be graphite / boron nitride (C / BN) nanocoaxial cables or silicon carbide / sulfur dioxide (CSi / SiO2) nanocoaxial cables, etc.

[0104] In some embodiments, the angle between the axis of the one-dimensional material in the electron excitation layer 121 and the emission direction of the emitted laser is 0 to 90°, for example, it can be 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80° or 90°.

[0105] In some embodiments, the axis of the one-dimensional material is the same as the laser emission direction, thereby enabling point emission of the electron source 100 with high resolution. If a low-density one-dimensional material arrangement is used, the emitted electron energy dispersion is low, and the brightness is high. If a high-density one-dimensional material arrangement is used, a large beam current of the electron source 100 can be achieved. Here, low density refers to the number of one-dimensional materials per unit area. For example, a density of less than 1 material per nm. 2 Low density, greater than 1 per nm 2 It is high density.

[0106] In some embodiments, the axis of the one-dimensional material forms an angle with the emission direction of the laser. The angle can be a right angle or an acute angle, and the laser excitation of the one-dimensional material can generate a linear electron source.

[0107] Optionally, the electron excitation layer 121 may also include a two-dimensional material. Electrons in the two-dimensional material can propagate along a two-dimensional plane. Combined with the electron excitation layer 121 being disposed on the light-emitting end 1102 of the optical fiber 110, this facilitates the efficient emission of electrons emitted by the electron source 100 along the extension direction of the optical fiber 110. Moreover, compared to setting a thin metal layer on the optical fiber, which would cause the melting point of the metal layer to decrease and thus lead to the problem of easy damage to the metal layer, the two-dimensional material selected in this application has no dangling bonds, is more stable, has a high melting point, and is not easily damaged. It is suitable for high-power excitation and high-current electron source 100. In addition, the energy levels of the two-dimensional material are more discrete, and the energy of the tunneled electron beam is more concentrated and the energy dispersion is smaller.

[0108] Two-dimensional materials are characterized by their atomic layer thickness, which can be a single atomic layer or multiple atomic layers thick. When lasers interact with two-dimensional materials, they have almost no impact on the light transmission mode, exhibiting high stability. Furthermore, the excited electrons can be emitted directly without internal scattering within the material, ensuring the purity of the emitted electrons and an extremely narrow pulse width.

[0109] Two-dimensional materials can be graphene, transition metal sulfides, two-dimensional perovskites, two-dimensional diamonds, or boron nitride, etc.

[0110] Taking graphene as an example of a two-dimensional material, the carbon atoms in graphene are bonded in-plane by covalent bonds, forming a hexagonal honeycomb planar structure. The electron excitation layer 121 can have a thickness of one atom, approximately 0.34 nanometers; the electron excitation layer 121 can also have a thickness of several or tens of atoms.

[0111] In some embodiments, the electron excitation layer 121 comprises at least one layer of two-dimensional material.

[0112] Optionally, the electron excitation layer 121 includes at least two layers of two-dimensional materials stacked sequentially along the laser emission direction, or the electron excitation layer 121 includes at least two two-dimensional materials of different materials connected to each other on the same plane.

[0113] In some embodiments, at least two layers of two-dimensional materials are stacked, or the electron excitation layer 121 includes at least two two-dimensional materials of different materials connected to each other on the same plane, thereby forming a vertical heterojunction or a planar heterojunction. The heterojunction structure can enhance the interaction between light and two-dimensional materials, realize efficient electron emission under laser power, and the heterojunction has the function of interface band modulation. Through material design and rotation angle modulation, special interface states can be obtained to achieve high brightness and low energy dissipation electron emission.

[0114] Of course, this application is not limited to this, and the electronic excitation layer 121 may also include two or more of zero-dimensional materials, one-dimensional materials and two-dimensional materials.

[0115] In some embodiments, the material in the electron excitation layer 121 includes a one-dimensional material and a zero-dimensional material disposed at the ends and / or sides of the one-dimensional material.

[0116] This application combines zero-dimensional materials with one-dimensional materials, placing the zero-dimensional material at the end and / or side of the one-dimensional material, that is, using zero-dimensional materials to modify the surface structure of the one-dimensional material. Both zero-dimensional and one-dimensional materials have typical discrete energy levels. Under the action of laser, electrons are mainly excited by tunneling from discrete energy levels. The emitted electrons have the characteristics of concentrated energy, small energy dispersion and high emission efficiency.

[0117] In some embodiments, the electron excitation layer 121 includes a zero-dimensional material and a two-dimensional material, wherein the zero-dimensional material is disposed on the surface of the two-dimensional material.

[0118] This application places zero-dimensional material on the surface of two-dimensional material. The two-dimensional material can not only serve as a support layer for supporting the zero-dimensional material, but also avoids the need for the additional conductive connection layer 130 by using a conductive two-dimensional material. That is, the two-dimensional material can serve as an auxiliary layer for the zero-dimensional material, achieving the functions of support and conductivity.

[0119] In some embodiments, the electron excitation layer 121 includes a one-dimensional material and a two-dimensional material, with the one-dimensional material disposed on the surface of the two-dimensional material; optionally, the angle between the axial direction of the one-dimensional material and the surface of the two-dimensional material is 0 to 90°.

[0120] In this application, a one-dimensional material is placed on the surface of a two-dimensional material. The two-dimensional material can not only serve as a support layer for the one-dimensional material, but also avoids the need for the additional conductive connection layer 130 by using a conductive two-dimensional material. That is, the two-dimensional material can serve as an auxiliary layer for the one-dimensional material, achieving the functions of support and conductivity.

[0121] In some embodiments, zero-dimensional materials, one-dimensional materials, or two-dimensional materials each independently include dopant elements.

[0122] This application improves the conductivity, alters the work function, and modulates the electron emission performance of low-dimensional materials by doping them with elements. For example, alkali metals and alkaline earth metals can improve the conductivity of low-dimensional materials while reducing their work function to increase the emission beam current. Elements such as B, C, N, O, F, and rare earth elements can create discrete energy levels to obtain narrow-energy electron beams.

[0123] Optionally, the doping element includes at least one of alkali metals, alkaline earth metals, transition metals, rare earth elements, halogens, and light elements (B, C, N, O, F).

[0124] In some embodiments, please refer to Figure 4The end face 11021 of the light-emitting end 1102 of the optical fiber 110 is set at an angle α with the extension direction of the fiber core 111, and the angle α is selected between 0 and 90 degrees. The electron emission layer 120 is disposed on the end face 11021 of the light-emitting end 1102 of the optical fiber 110, and the electron excitation layer 121 covers the fiber core 111 of the optical fiber 110. The laser emitted from the fiber core 111 can directly irradiate the electron emission layer 120, so that the electron excitation layer 121 is excited by the laser emitted from the fiber core 111 and emits electrons.

[0125] It is understandable that the electron excitation layer 121 is located on the light emission path of the laser emitted from the fiber core 111.

[0126] In this way, oblique incidence of electrons into the excitation layer 121 can be achieved, and a photoelectric field perpendicular to the end face 11021 of the light-emitting end 1102 can be realized. The emission angle of electrons can be changed by changing angle α, or the emission angle of electrons can be adjusted by adjusting the polarization state of the laser in the optical fiber 110, which is beneficial to broadening the application range of the electron source 100.

[0127] In some embodiments, please refer to Figure 5 and Figure 6 The light-emitting end 1102 of the optical fiber 110 has a light leakage notch h along the radial direction of the optical fiber 110. An electron emission layer 120 is disposed on the bottom wall surface h1 of the light leakage notch h, and the electron emission layer 120 includes at least an electron excitation layer 121. The bottom wall surface h1 of the light leakage notch h is planar, and the projection of the electron excitation layer 121 on the bottom wall surface h1 covers the projection of the fiber core 111 on the bottom wall surface h1. The electron excitation layer 121 also extends to the light-emitting end 1102 of the optical fiber 110.

[0128] Optionally, the light leakage gap h also has a sidewall h2 extending radially along the optical fiber 110, with the bottom wall h1 and the sidewall h2 jointly defining the light leakage gap h.

[0129] Optionally, the bottom wall surface h1 of the light leakage notch h is constructed as a plane, and the bottom wall surface h1 of the light leakage notch h extends along the extension direction of the optical fiber 110.

[0130] Alternatively, the bottom wall surface h1 of the light leakage notch h can be spaced apart from the fiber core 111, and the bottom wall surface h1 of the light leakage notch h can be parallel to the tangent plane of the outer surface of the fiber core 111; or the bottom wall surface h1 of the light leakage notch h can be tangent to the outer surface of the fiber core 111 (e.g., Figure 6 (as shown); Alternatively, the bottom wall surface h1 of the light leakage notch h can be constructed as a plane partially formed on the fiber core 111. For example, the fiber core 111 and the wrapping layer 112 can be cut simultaneously to form the light leakage notch h, and a portion of the bottom wall surface h1 of the light leakage notch h is formed on the fiber core 111, while the other portion is formed on the wrapping layer 112.

[0131] In this way, the laser transmitted in the core 111 of the optical fiber 110 can generate an evanescent wave at the bottom wall surface h1 of the light leakage notch h. Since the electron excitation layer 121 is located on the bottom wall surface h1 of the light leakage notch h, and the projection of the electron excitation layer 121 on the bottom wall surface h1 covers the projection of the core 111 on the bottom wall surface h1, the laser transmitted in the core 111 of the optical fiber 110 can interact with the electron excitation layer 121 through the evanescent wave, causing the electrons in the electron excitation layer 121 to absorb the energy of the evanescent wave and jump. These electrons can escape from the electron excitation layer 121, thereby realizing the excitation of electrons.

[0132] In some embodiments, please refer to Figure 7 and Figure 8 Optical fiber 110 includes perforated optical fiber, which has a light guide hole. The perforated optical fiber may include hollow perforated optical fiber, which may be a single-hole or multi-hole hollow optical fiber. Of course, the perforated optical fiber may also include solid perforated optical fiber, which may be a single-hole or multi-hole solid optical fiber. No specific restrictions are made here. Figures 7-8 An example of a hollow fiber with a single hole is given.

[0133] Specifically, such as Figures 7-8 In the illustrated embodiment, an air-filled fiber core 111 is disposed within the light guide aperture. The perforated optical fiber also includes a cladding layer 112 surrounding the fiber core 111. The cladding layer 112 is specifically constructed as an annular light guide tube, and the sidewall k of the light guide aperture is formed on the inner sidewall of the annular light guide tube. Specifically, the annular light guide tube can be made of borosilicate, glass, or quartz, etc. More specifically, the perforated optical fiber is a capillary optical fiber.

[0134] An electron excitation layer 121 is provided at least on the sidewall k of the light guide hole, and the electron excitation layer 121 extends along the extension direction of the light guide hole to the light output end 1102 of the optical fiber 110.

[0135] When the electron source 100 is in use, during the transmission of the laser through the light guide medium in the perforated optical fiber, an evanescent wave can be generated at the side wall k of the light guide hole. Since the electron excitation layer 121 is located on the side wall k of the light guide hole, the laser can interact with the electron excitation layer 121 through the evanescent wave, causing the electrons in the electron excitation layer 121 to absorb the energy of the evanescent wave and jump. These electrons can escape from the electron excitation layer 121, thereby achieving electron excitation.

[0136] In some embodiments, please refer to Figure 9 and Figure 10Optical fiber 110 includes perforated optical fiber, which has a light guide hole. The perforated optical fiber may include hollow perforated optical fiber, which may be a single-hole or multi-hole hollow optical fiber. Of course, the perforated optical fiber may also include solid perforated optical fiber, which may be a single-hole or multi-hole solid optical fiber. No specific restrictions are made here. Figures 9-10 An example of a hollow fiber with a single hole is given.

[0137] Specifically, such as Figures 9-10 In the illustrated embodiment, an air-filled fiber core 111 is disposed within the light guide aperture. The perforated optical fiber also includes a cladding layer 112 surrounding the fiber core 111. The cladding layer 112 is specifically constructed as an annular light guide tube, and the sidewall k of the light guide aperture is formed on the inner sidewall of the annular light guide tube. Specifically, the annular light guide tube can be made of borosilicate, glass, or quartz, etc. More specifically, the perforated optical fiber is a capillary optical fiber.

[0138] An electron emission layer 120 is disposed on the end face 11021 of the light-emitting end 1102 of the perforated optical fiber, and an electron excitation layer 121 covers one end of the light guide hole located at the end face 11021 of the light-emitting end 1102. The laser emitted from the perforated optical fiber can directly irradiate the electron emission layer 120, so that the electron excitation layer 121 is excited by the laser emitted from the perforated optical fiber and emits electrons.

[0139] For example, the perforated optical fiber is a capillary optical fiber, and the electron excitation layer 121 covers the core 111 of the perforated optical fiber. The electron excitation layer 121 can be directly covering the core 111 of the perforated optical fiber, or it can be indirectly covering the core 111 of the perforated optical fiber. No specific limitation is made here.

[0140] Thus, during the process of the laser propagating in the perforated optical fiber to the end face 11021 of the light-emitting end 1102 and being emitted, this part of the laser can interact with the electron excitation layer 121, causing the electrons in the electron excitation layer 121 to absorb the photons of the laser and undergo energy transition to escape from the electron excitation layer 121, thereby achieving electron excitation.

[0141] In some embodiments, please refer to Figure 11 and Figure 12 The optical fiber 110 has a tip j at the light-emitting end 1102. The electron excitation layer 121 covers the surface j1 of the tip j of the optical fiber 110. The optical fiber 110 includes a fiber core 111 for transmitting laser light. The laser light emitted from the fiber core 111 can directly irradiate the electron emission layer 120, so that the electron excitation layer 121 is excited by the laser light emitted from the fiber core 111 and emits electrons.

[0142] During the process of the laser transmitted within the core 111 of the optical fiber 110 being emitted from the tip j, this portion of the laser can interact with the electron excitation layer 121, causing electrons within the electron excitation layer 121 to absorb the photons of the laser and undergo energy transitions to escape from the electron excitation layer 121, thereby achieving electron excitation.

[0143] Optionally, the radial dimension of the tip j gradually decreases along the extension direction of the fiber core 111.

[0144] The electron excitation layer 121 of this application is disposed on the tip j of the optical fiber 110 and covers the surface j1 of the tip j of the optical fiber 110. Since the tip j of the optical fiber 110 has a geometric structure similar to a needle tip, the field emission enhancement factor is improved, and a higher brightness electron source 100 can be obtained.

[0145] Optionally, in this embodiment, along the extending direction of the fiber core 111, the size of the tip j is L1, and the size of the electron excitation layer 121 is L2, wherein L1 is greater than L2. Specifically, the size of the tip j and the size of the electron excitation layer 121 satisfy the following relationship: L2 > 1 / 2 * L1.

[0146] The electron excitation layer 121 covers the surface j1 of the tip j and is disposed around the tip j. Since L2 > 1 / 2 * L1, the contact area between the electron excitation layer 121 and the surface j1 of the tip j can be increased, the bonding strength between the electron excitation layer 121 and the optical fiber 110 can be improved, and it is also beneficial to use the laser transmitted by the fiber core 111 to excite the electron excitation layer 121 to emit electrons.

[0147] In some embodiments, the electron source 100 further includes a conductive connection layer 130, which is at least disposed on the light-emitting end 1102 of the optical fiber 110 and is electrically connected to the electron excitation layer 121.

[0148] The conductive connection layer 130 can be a conductive thin film. Specifically, the conductive connection layer 130 can be a metal thin film, a graphite thin film, or a low-dimensional material thin film, etc.

[0149] It should be noted that the conductive connection layer 130 is not located on the light output path of the laser emitted from the fiber core 111.

[0150] Thus, the electron excitation layer 121 can be electrically connected to the negative terminal of the power supply through the conductive connection layer 130. On the one hand, the power supply can be used to replenish electrons to the electron excitation layer 121, which is beneficial for the electron excitation layer 121 to continuously emit electrons under laser excitation. On the other hand, the direction and convergence of electrons emitted from the electron excitation layer 121 can be controlled by the voltage applied to the conductive connection layer 130 by the power supply. For example, the direction of electrons emitted from the electron excitation layer 121 can be controlled by the voltage applied to the anode target 200 and the conductive connection layer 130 by the power supply.

[0151] Optionally, the electron excitation layer 121 includes a first portion 1211 located on the light emission path of the laser emitted from the fiber core 111, and a second portion 1212 connected to the periphery of the first portion 1211. The second portion 1212 is electrically connected to the conductive connection layer 130. The second portion 1212 can directly contact the conductive connection layer 130 for electrical connection; alternatively, the second portion 1212 can be electrically connected to the conductive connection layer 130 through other conductive structures.

[0152] Specifically, such as Figure 4 In the embodiment shown, the first part 1211 and the second part 1212 are disposed on the end face 11021 of the light-emitting end 1102. The first part 1211 covers the fiber core 111 of the optical fiber 110, and the second part 1212 is disposed around the first part 1211 and electrically connected to the conductive connection layer 130.

[0153] The first part 1211 can directly cover the fiber core 111 of the optical fiber 110, or the first part 1211 can indirectly cover the fiber core 111 of the optical fiber 110, without specific restrictions.

[0154] Specifically, such as Figure 5 and Figure 6 In the embodiment shown, the first part 1211 and the second part 1212 are disposed on the bottom wall surface h1 of the light leakage gap h. The projection of the first part 1211 on the bottom wall surface h1 covers the projection of the fiber core 111 on the bottom wall surface h1. The second part 1212 is located on the periphery of the first part 1211 and is electrically connected to the conductive connection layer 130.

[0155] Specifically, such as Figure 7 and Figure 8 In the embodiment shown, the electron excitation layer 121 includes a first portion 1211 that completely covers the sidewall k of the light guide hole, and a second portion 1212 disposed on the end face 11021 of the light-emitting end 1102 of the perforated optical fiber. The first portion 1211 is connected to the second portion 1212, and the second portion 1212 is electrically connected to the conductive connection layer 130.

[0156] Specifically, such as Figure 9 and Figure 10In the embodiment shown, the electron excitation layer 121 includes a first portion 1211 and a second portion 1212 disposed on the end face 11021 of the light-emitting end 1102 and connected to each other. The first portion 1211 covers one end of the light guide hole located on the end face 11021 of the light-emitting end 1102. The second portion 1212 is disposed around the first portion 1211 and is electrically connected to the conductive connection layer 130.

[0157] Specifically, such as Figure 11 and Figure 12 In the illustrated embodiment, the electron excitation layer 121 includes a first portion 1211 and a second portion 1212 connected together. The projection of the first portion 1211 onto a target plane perpendicular to the extension direction of the fiber core 111 covers the projection of the fiber core 111 onto the target plane. The projection of the second portion 1212 onto the target plane is located outside the projection of the first portion 1211 onto the target plane, and the second portion 1212 overlaps with the conductive connection layer 130.

[0158] Thus, by electrically connecting the conductive connection layer 130 to the second part 1212 of the electron excitation layer 121, and considering that the second part 1212 is located on the periphery of the first part 1211, the conductive connection layer 130 can supplement electrons to the electron excitation layer 121 without affecting the interaction between the fiber core 111 and the electron excitation layer 121. This is beneficial for the electron excitation layer 121 to continuously emit electrons under laser excitation.

[0159] Optionally, the conductive connection layer 130 includes a first conductive portion 131 disposed on the light-emitting end 1102 and a second conductive portion 132 disposed on the circumferential side of the optical fiber 110. The first conductive portion 131 is connected to the second conductive portion 132, and the first conductive portion 131 overlaps with the second part 1212 of the electron excitation layer 121.

[0160] Specifically, such as Figure 4 , Figures 7-10 In the embodiment shown, the first conductive portion 131 is disposed on the end face 11021 of the light-emitting end 1102 and overlaps with the second portion 1212 of the electron excitation layer 121, specifically as follows: Figure 5 and Figure 6 In the illustrated embodiment, the first conductive portion 131 is disposed on the bottom wall surface h1 of the light leakage notch h and overlaps with the second portion 1212 of the electron excitation layer 121. The first conductive portion 131 also extends to the light-emitting end 1102. Specifically, as shown in the figure... Figure 11 and Figure 12 In the embodiment shown, the first conductive part 131 is disposed on the tip j of the light-emitting end 1102 and overlaps with the second part 1212 of the electron excitation layer 121.

[0161] In this way, the conductive connection layer 130 can cover more of the optical fiber 110, improving the bonding strength between the conductive connection layer 130 and the optical fiber, and also making it easier to use the conductive connection layer 130 to supplement electrons to the electron excitation layer 121.

[0162] Optionally, the conductive connection layer 130 includes a first metal layer and a second metal layer stacked together, wherein the adhesion of the first metal layer is greater than that of the second metal layer, and the corrosion resistance of the first metal layer is less than that of the second metal layer.

[0163] For example, the first metal layer is made of titanium, and the second metal layer is made of gold.

[0164] Thus, the first metal layer with higher adhesion allows the conductive connection layer 130 to adhere better to the optical fiber 110, and the second metal layer with better corrosion resistance protects the first metal layer, improving the bonding strength between the conductive connection layer 130 and the optical fiber 110, which also helps to improve the service life of the conductive connection layer 130.

[0165] In some embodiments, the electron emission layer 120 further includes an auxiliary layer 122, which is stacked on the side of the electron excitation layer 121 near the optical fiber 110, or stacked on the side of the electron excitation layer 121 away from the optical fiber 110.

[0166] Alternatively, the auxiliary layer 122 may be stacked on one side of the electron excitation layer 121 near the light-emitting end 1102 of the optical fiber 110, or the auxiliary layer 122 may be stacked on one side of the electron excitation layer 121 away from the light-emitting end 1102 of the optical fiber 110.

[0167] Alternatively, the auxiliary layer 122 can be stacked on one side of the bottom wall surface h1 of the electron excitation layer 121, near or far from the light leakage notch h.

[0168] Alternatively, the auxiliary layer 122 can be stacked on one side of the surface j1 of the electron excitation layer 121, near or away from the tip j of the optical fiber 110.

[0169] Figure 9 , Figure 10 and Figure 13 An example is given where the auxiliary layer 122 is stacked on one side of the end face 11021 of the electron excitation layer 121 near the light-emitting end 1102.

[0170] In this application, an auxiliary layer 122 is added. When the electron excitation layer 121 needs structural support, the auxiliary layer 122 is used to provide structural support for the electron excitation layer 121, that is, the electron excitation layer 121 is disposed on the auxiliary layer 122; or, when the electron excitation layer 121 cannot be directly connected to the conductive connection layer 130, it is connected to the conductive connection layer 130 through the conductive auxiliary layer 122, and the electron excitation layer 121 and the conductive connection layer 130 are made electronically connected by the auxiliary layer 122.

[0171] Optionally, the auxiliary layer 122 includes at least one of a conductive support layer and a heat dissipation support layer.

[0172] Optionally, the thickness of the auxiliary layer 122 is 0.1 nm to 100 nm.

[0173] Optionally, the light transmittance of the auxiliary layer 122 is 10% or more, such as 15%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100%.

[0174] Optionally, the auxiliary layer 122 includes a conductive support layer, which is electrically connected to the conductive connection layer 130.

[0175] In some embodiments, the auxiliary layer 122 includes a conductive support layer, the material of which includes a conductive metal, and the laser wavelength in the optical fiber 110 is 200nm to 10μm, the pulse power is 1nw to 1w, and the repetition frequency is 0Hz to 10GHz.

[0176] The auxiliary layer 122 in this application is made of conductive metal, and the laser parameters are controlled to avoid the problem of melting caused by laser irradiation of conductive metal, thereby ensuring that the auxiliary layer has the functions of support and conductivity.

[0177] The auxiliary layer 122 may also include a conductive support layer, such as Figure 9 and Figure 10 As shown, the electron excitation layer 121 is disposed on the end face 11021 of the light-emitting end 1102 via an auxiliary layer 122. The auxiliary layer 122 has a bearing plane for supporting the electron excitation layer 121. The auxiliary layer 122 can be a light-transmitting material; the auxiliary layer 122 can also be a non-light-transmitting material, and the auxiliary layer 122 has a ring structure. The orthographic projection of the auxiliary layer 122 on the end face 11021 of the light-emitting end 1102 is located around the core 111 of the optical fiber 110.

[0178] In this way, the bearing plane of the auxiliary layer 122 can be used to make the electron excitation layer 121 more flatly disposed on the end face 11021 of the light-emitting end 1102, without affecting the interaction between the electron excitation layer 121 and the fiber core 111 of the optical fiber 110. This is conducive to the formation of small electron beams with concentrated and diffused energy by electrons tunneling and emitted from the electron excitation layer 121.

[0179] The auxiliary layer 122 may also include a heat dissipation support layer. For example, the auxiliary layer 122 may be made of hexagonal boron nitride. However, other materials that can dissipate heat from the electron excitation layer 121 and allow the electron excitation layer 121 to be flatly disposed on the end face 11021 of the light-emitting end 1102 can also be used. In this way, the auxiliary layer 122 can increase the heat dissipation efficiency of the electron excitation layer 121, enabling the electron excitation layer 121 to emit a larger electron beam.

[0180] In some embodiments, along the extension direction of the optical fiber 110, the anode target 200 and the light-emitting end 1102 of the optical fiber 110 are spaced apart, and there is a preset electric field between the anode target 200 and the electron excitation layer 121, so that the electrons emitted from the electron excitation layer 121 can be accelerated linearly along the extension direction of the optical fiber 110.

[0181] Compared to using a gate structure as an accelerating electrode, in the X-ray tube 10 of this application, a preset electric field is set between the anode target 200 and the electron excitation layer 121 to form linear acceleration of electrons along the direction of the electron excitation layer 121 pointing to the anode target 200, which greatly simplifies the structure of the X-ray tube 10 and thus helps to reduce the volume of the X-ray tube 10.

[0182] In this embodiment, the electron excitation layer 121 is connected to the negative terminal of an external power supply through the conductive connection layer 130, and the anode target 200 is connected to the positive terminal of the external power supply, so that there is a preset electric field between the anode target 200 and the electron excitation layer 121. Since the anode target 200 and the light-emitting end 1102 of the optical fiber 110 are spaced apart along the extension direction of the optical fiber 110, the electrons emitted from the electron excitation layer 121 can be emitted towards the anode target 200 along the extension direction of the optical fiber 110 under the action of the preset electric field, which can better excite the anode target 200 and make the anode target 200 emit X-rays with more concentrated energy.

[0183] Optionally, the light-inlet end 1101 of the optical fiber 110 extends out of the vacuum chamber 301 through the first port 302 described below, and the second conductive part 132 of the conductive connection layer 130 is disposed on the circumferential side of the optical fiber 110, and part of the structure of the second conductive part 132 is disposed on the circumferential side of the optical fiber 110 located outside the vacuum chamber 301, so as to facilitate the connection of the negative terminal of the external power supply to the conductive connection layer 130.

[0184] In some embodiments, the conductive connection layer 130 is disposed around the optical fiber 110.

[0185] In this way, the contact area between the conductive connection layer 130 and the optical fiber 110 can be increased, thereby improving the bonding strength between the conductive connection layer 130 and the optical fiber 110.

[0186] In some embodiments, the tube 300 is respectively sleeved on the optical fiber 110 and the anode target 200.

[0187] The inner peripheral wall of the tube body 300 can be adapted and connected to the outer peripheral wall of the optical fiber 110 by bonding. Alternatively, the outer peripheral wall of the anode target 200 can be bonded to the inner peripheral wall of the tube body 300 by bonding. This allows the X-ray tube 10 to be assembled while the outer peripheral walls of the optical fiber 110 and the anode target 200 are designed to be of similar size to the inner peripheral wall of the tube body 300. This reduces the radial dimension of the X-ray tube 10, thereby reducing its volume. As a result, the X-ray tube 10 occupies less space and has a higher material utilization rate, giving the electron source 100 the advantage of high integration.

[0188] In some embodiments, the tube body 300 has a first port 302 communicating with the vacuum chamber 301, the light-emitting end 1102 of the optical fiber 110 extends into the vacuum chamber 301 through the first port 302, and the outer peripheral wall of the optical fiber 110 is sealed to the inner peripheral wall of the first port 302.

[0189] This improves the sealing performance of the vacuum chamber 301, and the electron excitation layer 121 can emit electrons from the light-emitting end 1102 under the excitation of the laser transmitted by the fiber core 111. Furthermore, the electron excitation layer 121 can better emit electrons toward the anode target 200 within the vacuum chamber 301, thereby improving the reliability of the X-ray tube 10.

[0190] Specifically, the tube 300 and the optical fiber 110 can be assembled in a vacuum environment, and the inner peripheral wall of the tube 300 and the outer peripheral wall of the optical fiber 110 can be sealed together, which can improve the sealing performance of the vacuum chamber 301.

[0191] In some embodiments, the tube body 300 further has a second port 303 disposed opposite to the first port 302, and the side of the anode target 200 away from the light-emitting end 1102 extends out of the vacuum chamber 301 through the second port 303, and the outer peripheral wall of the anode target 200 is sealed to the inner peripheral wall of the second port 303.

[0192] Thus, on the one hand, the outer peripheral wall of the anode target 200 is sealed to the inner peripheral wall of the second port 303, which can assemble the anode target 200 and the tube body 300 together, and also helps to improve the sealing performance of the vacuum chamber 301; on the other hand, the side of the anode target 200 away from the light-emitting end 1102 extends out of the vacuum chamber 301, which makes it convenient for the anode target 200 to be connected to the positive terminal of an external power supply.

[0193] Specifically, the anode target 200 and the optical fiber 110 can be assembled in a vacuum environment. The inner peripheral wall of the tube body 300 and the outer peripheral wall of the anode target 200 can be bonded together with sealant, which can improve the sealing performance of the vacuum chamber 301.

[0194] In some embodiments, the X-ray tube 10 further includes an external electrode 400, which is disposed between the outer peripheral wall of the anode target 200 and the inner peripheral wall of the second port 303. Along the longitudinal extension direction of the tube body 300, one end of the external electrode 400 is located inside the vacuum chamber 301, and the other end extends outside the vacuum chamber 301.

[0195] On the one hand, the anode target 200 can be connected to the positive terminal of an external power source through the external electrode 400. On the other hand, the external electrode 400 is arranged around the outer peripheral wall of the anode target 200 and is partially located in the vacuum chamber 301, which can increase the contact area between the external electrode 400 and the anode target 200, improve the bonding strength between the external electrode 400 and the anode target 200, and better utilize the external electrode 400 to provide a preset voltage to the anode target 200.

[0196] In some embodiments, please refer to Figures 1-3 Along the extension direction of the optical fiber 110, the electron source 100 and the anode target 200 are spaced apart. The anode target 200 has a reflective target surface 210 facing the light-emitting end 1102. The reflective target surface 210 is set at an angle β with the extension direction of the optical fiber 110. Wherein, β is greater than 0 degrees and less than 90 degrees. The output window 311 is provided on the side wall of the tube body 300 and is set facing the reflective target surface 210.

[0197] Optionally, the anode target 200 with a reflective target surface 210 can be made of materials such as tungsten, silver, palladium, rhodium, molybdenum, copper, nickel, cobalt, iron, or chromium.

[0198] In this way, the electron source 100 can emit electrons toward the reflective target surface 210 of the anode target 200, which can excite the anode target 200 to emit X-rays, and the X-rays are reflected by the reflective target surface 210 and emitted outside the vacuum chamber 301 through the output window 311.

[0199] In other embodiments, please refer to Figure 14 and Figure 15 The anode target 200 includes a transmission anode 220. Along the longitudinal extension direction of the tube body 300, the electron source 100 and the output window 311 are located at opposite ends of the tube body 300, and the transmission anode 220 is located between the electron source 100 and the output window 311.

[0200] The transmission anode 220 may include a substrate and a metal layer disposed on the side of the substrate facing the light-emitting end 1102, the thickness of the metal layer being less than 100 nm. The substrate may be made of any X-ray transmission material, for example, glass. The metal layer may be made of tungsten, silver, palladium, rhodium, molybdenum, copper, nickel, cobalt, iron, or chromium, and may be a metal plating.

[0201] Thus, the electron source 100 at one end of the tube 300 emits electrons toward the anode target 200, which can excite the anode target 200 to emit X-rays that penetrate the anode target 200, and then exit through the output window 311 at the other end of the tube 300.

[0202] It can be, such as Figure 1 and Figure 14 As shown, the light-inlet end 1101 of the optical fiber 110 extends out of the vacuum chamber 301 through the first port 302. In this way, part of the structure of the second conductive part 132 can be located on the circumferential side of the optical fiber 110 outside the vacuum chamber 301, which facilitates the connection of the conductive connection layer 130 to the negative terminal of the external power supply.

[0203] Alternatively, the end face of the light-inlet end 1101 of the optical fiber 110 can be flush with the plane of the first port 302 (not shown in the figure). In this way, the optical fiber 110 can be roughly encapsulated in the tube 300, and the end face of the light-inlet end 1101 of the optical fiber 110 can be exposed through the first port 302 so that the laser source can be coupled to the light-inlet end 1101 of the optical fiber 110. This better protects the optical fiber 110 and also facilitates the transmission of the laser emitted by the laser source through the optical fiber 110.

[0204] In some embodiments, the tube body 300 includes an inner tube 310 sleeved on the optical fiber 110 and the anode target 200, and an outer tube 320 sleeved on the inner tube 310. The outer tube 320 is provided with an opening 321, and part of the structure of the inner tube 310 is exposed through the opening 321 to form an output window 311. The material of the inner tube 310 includes an X-ray transmission material, and the material of the outer tube 320 includes an X-ray blocking material.

[0205] Specifically, such as Figure 1 In the embodiment shown, the opening 321 is located on one side of the outer tube 320. Specifically, as shown... Figure 14 In the embodiment shown, the opening 321 is located at the end of the outer tube 320 away from the electronic source 100, so that the electronic source 100 and the output window 311 can be arranged opposite each other along the extension direction of the optical fiber 110.

[0206] Alternatively, the X-ray transmission material may include glass, beryllium, aluminum, titanium, or sapphire.

[0207] Alternatively, X-ray blocking materials may include lead or barium sulfate.

[0208] In this way, the outer tube 320 can be used to block X-rays, and the inner tube 310 can be used to expose X-rays through the opening 321, i.e., the output window 311, to emit X-rays outwards. This reduces the possibility of X-rays escaping from other parts of the inner tube 310 except for the output window 311, thereby improving the safety and reliability of the X-ray tube 10. At the same time, it also achieves concentrated X-ray emission and low-loss X-ray emission from vacuum to the outside world.

[0209] In some embodiments, the outer diameter of the tube 300 is 125μm-2000μm, and the length of the tube 300 is 3cm-9cm.

[0210] With the tube body 300 respectively mounted on the optical fiber 110 and the anode target 200, the radial dimension of the X-ray tube 10 is small, which can greatly reduce the volume of the X-ray tube 10. This allows the electron excitation layer 121 and the anode target 200 to accelerate electrons well in the small vacuum chamber 301, which is conducive to the high integration and miniaturization of the electron source 100 and the X-ray emission structure. It also helps to realize the portable application of the X-ray tube 10 and metal flaw detection in confined spaces.

[0211] In some embodiments, the distance between the light-emitting end 1102 of the optical fiber 110 and the anode target 200 along the extension direction of the optical fiber 110 can be 3cm-5cm. Of course, the distance between the light-emitting end 1102 of the optical fiber 110 and the anode target 200 in this application is not limited to this; 3cm-5cm is used as an example for illustration here.

[0212] In this application, the small spacing between the electron excitation layer 121 and the anode target 200 results in a more uniform electric field line between them, leading to more electrons being effectively accelerated and incident on the anode target 200, thus exciting the anode target 200 to emit X-rays. This also facilitates the miniaturization of the X-ray tube 10.

[0213] The method for preparing the X-ray tube 10 includes the following steps:

[0214] S20 provides an electron source 100, an anode target 200, and a tube body 300.

[0215] Taking the formation of an electron excitation layer 121 covering the fiber core 111 on the light-emitting end 1102 of the optical fiber 110 as an example, the preparation method of the electron source 100 includes the following steps:

[0216] S210, Provide optical fiber 110. The optical fiber 110 includes a fiber core 111 for transmitting laser light and a cladding layer 112 wrapped around the fiber core 111.

[0217] Optionally, an appropriate length of optical fiber 110 can be cut, the end coating of the optical fiber 110 can be removed, and one end of the optical fiber 110 can be cut to form an emitting end 1102. Specifically, a cutting mechanism can be used to cut one end of the optical fiber 110 to form the emitting end 1102. By forming the emitting end 1102 by cutting, the cross-section of the end face 11021 of the emitting end 1102 can be relatively flat, which is beneficial to forming a flat electron emission layer 120 on the end face 11021 of the emitting end 1102.

[0218] S220. An electron emission layer 120 is formed on the end face 11021 of the light-emitting end 1102 of the optical fiber 110. The electron emission layer 120 includes at least an electron excitation layer 121. The electron excitation layer 121 covers the fiber core 111 of the optical fiber 110 so that the electron excitation layer 121 is located on the light-emitting path of the laser emitted from the fiber core 111.

[0219] The electron-excited layer 121 can be formed by at least one of dry transfer, wet transfer and direct growth.

[0220] In some embodiments, the electron excitation layer 121 is prepared by a dry transfer method, which includes: transferring zero-dimensional material, one-dimensional material and / or two-dimensional material onto an adhesive tape by mechanical peeling, and transferring the zero-dimensional material, one-dimensional material and / or two-dimensional material onto the end face 11021 of the light-emitting end 1102 of the optical fiber 110.

[0221] Taking two-dimensional materials as an example, the preparation process of forming the electron emission layer 120 using a dry transfer method is as follows:

[0222] (1) The two-dimensional material can be thinned by mechanical peeling until an electron excitation layer 121 of a preset thickness is formed. Specifically, the two-dimensional material is bonded to a high-adhesion tape A, and a low-adhesion tape B can be used to mechanically peel it along the crystal cleavage plane of the two-dimensional material, repeating the process multiple times until an electron excitation layer 121 of a preset thickness is formed.

[0223] (2) Transfer the electron excitation layer 121 of a preset thickness onto the temporary substrate 20 and remove the tape B from the electron excitation layer 121. Specifically, the tape B can be melted by heating to peel the tape B off the electron excitation layer 121.

[0224] (3) Transfer the electron excitation layer 121 on the temporary substrate 20 to the end face 11021 of the light-emitting end 1102 of the optical fiber 110.

[0225] Optionally, the electron excitation layer 121 may be made of a two-dimensional material, and the temporary substrate 20 may be made of a polypropylene carbonate film.

[0226] Of course, this application is not limited to this. The dry transfer method can also be combined with a direct growth method (such as chemical vapor deposition). For example, an electron excitation layer 121 of a predetermined thickness can be grown on the substrate to be peeled off. Then, the electron excitation layer 121 can be transferred from the substrate to be peeled off to a temporary substrate 20 by acid etching or manual tearing. Then, the electron excitation layer 121 on the temporary substrate 20 can be transferred to the end face 11021 of the light-emitting end 1102 of the optical fiber 110. The substrate to be peeled off can be metal or other materials that can be acid-etched or manually torn.

[0227] In other embodiments, the electron excitation layer 121 is prepared by a wet transfer method, which includes: preparing zero-dimensional, one-dimensional or two-dimensional materials directly in a solution and floating them on the liquid surface, making the end face 11021 of the light-emitting end 1102 of the optical fiber 110 contact the zero-dimensional, one-dimensional or two-dimensional materials on the liquid surface, and drying the zero-dimensional, one-dimensional and / or two-dimensional materials on the end face 11021 of the light-emitting end 1102 of the optical fiber 110.

[0228] In some embodiments, the electron excitation layer 121 is prepared by direct growth, and the preparation method includes: preparing the electron excitation layer 121 directly on the end face 11021 of the light-emitting end 1102 of the optical fiber 110 by at least one of chemical vapor deposition, physical vapor deposition, molecular beam epitaxy and liquid filling.

[0229] Optionally, before or after forming the electron emission layer 120 on the end face 11021 of the light-emitting end 1102 of the optical fiber 110, the method for fabricating the electron source 100 further includes:

[0230] S230, a conductive connection layer 130 is formed on the end face 11021 of the light-emitting end 1102 of the optical fiber 110 so that the conductive connection layer 130 overlaps with the electronic excitation layer 121.

[0231] In other words, the conductive connection layer 130 can be formed first, followed by the electron excitation layer 121; or the electron excitation layer 121 can be formed first, followed by the conductive connection layer 130. As long as the electron excitation layer 121 and the conductive connection layer 130 are electrically connected to each other, the electron excitation layer 121 can be supplemented with electrons through the conductive connection layer 130, which is beneficial for the electron excitation layer 121 to continuously emit electrons under laser excitation.

[0232] Optionally, a conductive connection layer 130 is formed on the end face 11021 of the light-emitting end 1102 of the optical fiber 110, so that the conductive connection layer 130 overlaps with the electronic excitation layer 121, specifically including:

[0233] S231. A core protection layer is formed on the end face 11021 of the light-emitting end 1102 of the optical fiber 110, and the core protection layer covers the core 111 of the optical fiber 110.

[0234] It is possible that the core protective layer directly covers the core 111 of the optical fiber 110, or it is possible that the core protective layer indirectly covers the core 111 of the optical fiber 110; no specific restrictions are imposed here.

[0235] Optionally, the polymer microsphere solution can be coated onto the end face 11021 of the light-emitting end 1102 of the optical fiber 110 to form a core protective layer covering the fiber core 111. For example, the polymer microsphere solution is a polymethyl methacrylate suspension.

[0236] S232. A conductive material layer covering the fiber core protective layer is formed on the optical fiber 110.

[0237] The conductive material layer can be formed by vapor deposition. Specifically, a metal vapor deposition device can be used to form the conductive material layer on the optical fiber 110.

[0238] S233. Remove the portion of the fiber core protective layer and conductive material layer disposed on the fiber core protective layer to form a conductive connection layer 130.

[0239] Optionally, a solvent capable of dissolving the fiber core protective layer and not interacting with the conductive material layer can be used to remove the fiber core protective layer. Specifically, acetone can be used to soak the light-emitting end 1102 of the optical fiber 110, causing the fiber core protective layer (polymer microspheres) to dissolve and the portion of the conductive material layer (partial metal plating) disposed on the fiber core protective layer to peel off, thereby obtaining the conductive connection layer 130.

[0240] It is understood that the core protection layer can be used to make the orthographic projection of the conductive connection layer 130 on the end face 11021 of the light-emitting end 1102 and the orthographic projection of the core 111 of the optical fiber 110 on the end face 11021 of the light-emitting end 1102 do not coincide, so that the laser transmitted in the core 111 of the optical fiber 110 can better interact with the electron excitation layer 121 covering the core 111 of the optical fiber 110.

[0241] In some embodiments, please refer to Figure 16 Step S220, which forms an electron emission layer 120 on the end face 11021 of the light-emitting end 1102 of the optical fiber 110, specifically includes the following steps: Specifically, the steps for transferring the electron excitation layer 121 on the temporary substrate 20 to the end face 11021 of the light-emitting end 1102 of the optical fiber 110 are as follows:

[0242] S221. The electron excitation layer 121 and the end face 11021 of the light-emitting end 1102 of the optical fiber 110 are arranged opposite to each other along the first direction F1 and are parallel to each other.

[0243] Specifically, the end face 11021 of the light-emitting end 1102 of the optical fiber 110 and the electron excitation layer 121 are observed under a microscope. The electron excitation layer 121 and the end face 11021 of the light-emitting end 1102 of the optical fiber 110 are arranged opposite to each other and parallel to each other along the first direction F1, and the center line connecting the two extends along the first direction F1.

[0244] S222, drive the optical fiber 110 to move along the first direction F1 to contact the electron excitation layer 121.

[0245] S223. At a preset temperature, the electron excitation layer 121 is attached to the end face 11021 of the light-emitting end 1102 of the optical fiber 110.

[0246] In this way, the center of the electron excitation layer 121 can be aligned with the center of the end face 11021 of the light-emitting end 1102 of the optical fiber 110 using a microscope, and the two can be bonded to each other at a certain temperature. This allows the electron excitation layer 121 and the end face 11021 of the light-emitting end 1102 of the optical fiber 110 to be tightly bonded under the action of van der Waals forces, improving the bonding strength of the electron excitation layer 121 on the optical fiber 110. It also helps the electron excitation layer 121 to completely cover the fiber core 111 of the optical fiber 110, so that the laser transmitted through the fiber core 111 can better interact with the electron excitation layer 121.

[0247] In some specific embodiments, step S220 of forming an electron emission layer 120 on the end face 11021 of the light-emitting end 1102 of the optical fiber 110 specifically includes the following steps: Specifically, the steps of transferring the electron excitation layer 121 on the temporary substrate 20 to the end face 11021 of the light-emitting end 1102 of the optical fiber 110 are as follows:

[0248] S2201. Attach an annular heating plate 40 to the back of the perforated slide 30 of the microscope. Fix a temporary substrate 20 with an electron excitation layer 121 to the bottom side of the annular heating plate 40 (the temporary substrate 20 can be fixed to the bottom side of the annular heating plate 40 by adhesive bonding). Set the electron excitation layer 121 on the temporary substrate 20 downwards, and fix the optical fiber 110 below the electron excitation layer 121. This ensures that the central axis of the microscope objective, the central axis of the perforated slide 30, the central axis of the annular heating plate 40, the center of the electron excitation layer 121, and the center of the fiber core 111 coincide. The microscope objective, perforated slide 30, annular heating plate 40, electron excitation layer 121, and optical fiber 110 are arranged sequentially from top to bottom.

[0249] Optionally, a clamp can be used to fix the optical fiber 110 on the moving platform, and the end face 11021 of the light-emitting end 1102 of the optical fiber 110 can be set upward. The moving platform is used to adjust the position of the optical fiber 110 along the first direction F1, and to adjust the angle of the end face 11021 of the light-emitting end 1102 of the optical fiber 110 relative to the horizontal plane, so that it is set horizontally.

[0250] Alternatively, the clamp can be a pneumatic gripper or an electric gripper.

[0251] Optionally, the moving platform can be a six-degree-of-freedom platform. The moving platform may also include a linear drive mechanism and a rotary drive mechanism connected to the linear drive mechanism. The output end of the rotary drive mechanism is connected to a fixture to drive the fixture and the optical fiber 110 held by the fixture to rotate about an axis parallel to the horizontal plane, so that the end face 11021 of the light-emitting end 1102 is horizontally positioned. The linear drive mechanism is used to drive the rotary drive mechanism, the fixture, and the optical fiber 110 to move along a first direction F1.

[0252] The linear drive mechanism can be a motor or a cylinder, and the rotary drive mechanism can be a motor or a rotary cylinder.

[0253] S2202. Observe the end face 11021 of the light-emitting end 1102 of the optical fiber 110 and the electron excitation layer 121 under a microscope, and arrange the electron excitation layer 121 and the end face 11021 of the light-emitting end 1102 of the optical fiber 110 opposite to each other along the first direction F1 and parallel to each other, and arrange the center line connecting the two to extend along the first direction F1.

[0254] The end face 11021 of the light-emitting end 1102 and the center alignment of the electron excitation layer 121 can be achieved with the aid of a microscope.

[0255] S2203. Connect the annular heating element 40 to an external power source to apply a first preset voltage to the annular heating element 40 and preheat the electron excitation layer 121 on the temporary substrate 20 (heat to the preheating temperature), which is beneficial for the electron excitation layer 121 to be more flat.

[0256] Optionally, the first preset voltage is 1V-1.5V, and the preheating temperature is 50-60℃.

[0257] S2204, drive the optical fiber 110 to move along the first direction F1 to contact the electron excitation layer 121. This allows Newton's rings to appear when the end face 11021 of the light-emitting end 1102 contacts the electron excitation layer 121.

[0258] S2205. At a preset temperature, the electron excitation layer 121 is tightly attached to the end face 11021 of the light-emitting end 1102 of the optical fiber 110. Specifically, this includes: applying a second preset voltage to the annular heating plate 40 and heating the electron excitation layer 121 on the temporary substrate 20 to the preset temperature, which is beneficial for the electron excitation layer 121 to be more tightly attached to the end face 11021 of the light-emitting end 1102.

[0259] Optionally, the second preset voltage is 2.5V-4V and the preset temperature is 90-100℃.

[0260] S2206. Remove the temporary substrate 20. The temporary substrate 20 can be removed by a combination of melting and heating and solvent immersion. Specifically, a third preset voltage is applied to the annular heating element 40, and the temporary substrate 20 is heated to the melting temperature and melted. It should be noted that the melting point of the electron excitation layer 121 is much higher than that of the temporary substrate 20.

[0261] Optionally, the third preset voltage is 5.5V-6V, and the melting temperature is 130-150℃.

[0262] After the electron excitation layer 121 is tightly disposed on the end face 11021 of the light-emitting end 1102, the portion of the temporary substrate 20 in contact with the annular heating plate 40 can be melted by molten heating. The electron excitation layer 121 can then detach from the annular heating plate 40 and remain tightly attached to the end face 11021 of the light-emitting end 1102 of the optical fiber 110, facilitating the subsequent removal of the temporary substrate 20 remaining on the electron excitation layer 121. The portion of the temporary substrate 20 not in contact with the annular heating plate 40 remains on the electron excitation layer 121. The optical fiber 110 can then be removed from the fixture, and the light-emitting end 1102 of the optical fiber 110 can be immersed in acetone to dissolve the temporary substrate 20 remaining on the electron excitation layer 121 and completely remove the temporary substrate 20.

[0263] The preparation method of the anode target 200 includes the following steps:

[0264] S310. Select copper wire according to the inner diameter of tube 300 to serve as anode target 200. The outer diameter of copper wire is approximately equal to the inner diameter of tube 300 so that tube 300 can be fitted onto anode target 200.

[0265] S320. One end of the anode target 200 is cut to form a reflective target surface 210, and the reflective target surface 210 is ground and polished. The anode target 200 is also straightened and shaped. For example, the reflective target surface 210 is set at a 45° angle to the longitudinal extension direction of the anode target 200.

[0266] By polishing the reflective target surface 210, the reflective target surface 210 can be made smoother, which is more conducive to the control of X-ray emission angle and performance. Considering that copper wire is easy to bend during processing, this application straightens and shapes the anode target 200, which is more conducive to the subsequent assembly of the anode target 200 into the tube body 300.

[0267] S330. An external electrode 400 is welded to the end of the anode target 200 away from the reflective target surface 210. The external electrode 400 is sleeved on the anode target 200 and is used to electrically connect to the positive terminal of the power supply.

[0268] The conductive connection layer 130 of the electron source 100 is used to electrically connect to the negative terminal of the power supply. When the X-ray tube 10 is in use, the electrons emitted from the electron excitation layer 121 can be emitted towards the anode target 200 along the extension direction of the optical fiber 110 under the action of a preset electric field, which can better excite the anode target 200 and make the anode target 200 emit X-rays with more concentrated energy.

[0269] S40. Determine and mark the installation positions of the electron source 100 and the anode target 200 on the tube body 300.

[0270] S60. In a vacuum environment, the electron source 100 and the anode target 200 are installed at the corresponding marked positions. The electron source 100 and the anode target 200 can be bonded to the corresponding marked positions so that the tube body 300 is respectively sleeved on the optical fiber 110 of the electron source 100 and the anode target 200. The external electrode 400 is placed between the outer peripheral wall of the anode target 200 and the inner peripheral wall of the second port 303. Then, the part of the tube body 300 sleeved on the optical fiber 110 and the part of the tube body 300 sleeved on the anode target 200 are clamped and fixed to seal the tube body 300 and form a vacuum chamber 301.

[0271] The embodiments of the present invention will be described in detail below with reference to examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. For experimental methods in the following embodiments where specific conditions are not specified, please refer to the guidelines given in this invention, or follow experimental manuals or conventional conditions in the art, or follow the conditions recommended by the manufacturer, or refer to experimental methods known in the art.

[0272] Example 1

[0273] The optical fiber 110 is a single-mode optical fiber. The diameter of the fiber core 111 of the optical fiber 110 is 8.2 μm, the diameter of the optical fiber 110 is 125 μm, and the angle α is selected as 30 degrees, that is, the oblique angle of the optical fiber 110 forms a 30-degree angle with the axis of the optical fiber 110. The wavelength of the laser transmitted in the optical fiber 110 is 1550 nm. The conductive connection layer 130 includes 5 nm of titanium and 60 nm of gold stacked on the optical fiber 110. The fiber core 111 at the end face 11021 of the light-emitting end 1102 is exposed (without the conductive connection layer 130 covering it). The electron excitation layer 121 is made of two-dimensional graphene material (1 nm thick). The shape of the graphene material is not limited; it can be polygonal, circular, or elliptical, etc. The electron excitation layer 121 is disposed on the end face 11021 of the light-emitting end 1102 of the optical fiber 110 and completely covers the fiber core 111 of the optical fiber 110. For example, along the radial direction of the optical fiber 110, the size of the electron excitation layer 121 is 30-60 μm (much larger than the diameter of the fiber core 111). In this embodiment, along the radial direction of the optical fiber 110, the size of the electron excitation layer 121 is 50 μm. A copper wire with a diameter of 125 micrometers is selected as the anode target 200, with β being 45°, meaning that the extension direction of the reflective target surface 210 and the optical fiber 110 is at a 45° angle. The inner tube 310 of the tube body 300 is a beryllium hollow tube with an inner diameter of 125 micrometers, an outer diameter of 300 micrometers, and a length of 6 centimeters. The outer tube 320 is a lead hollow tube with an inner diameter of 300 micrometers, an outer diameter of 1000 micrometers, and a length of 6 centimeters. The output window 311 is square, with a length and width of 200 micrometers.

[0274] Example 2

[0275] The optical fiber 110 is a single-mode optical fiber. The diameter of the fiber core 111 of the optical fiber 110 is 8.2 μm, the diameter of the optical fiber 110 is 125 μm, and the wavelength of the laser transmitted in the optical fiber 110 is 1550 nm. The conductive connection layer 130 includes 5 nm of titanium and 60 nm of gold stacked on the optical fiber 110, wherein the fiber core 111 at the light-emitting end 1102 is exposed (without being covered by the conductive connection layer 130). The electron excitation layer 121 is made of graphene two-dimensional material (the thickness of the graphene two-dimensional material is 8nm). The shape of the graphene two-dimensional material is not limited and can be polygonal, circular or elliptical, etc. The electron excitation layer 121 is disposed on the end face 11021 of the light-emitting end 1102 of the optical fiber 110 and completely covers the fiber core 111 of the optical fiber 110. For example, along the radial direction of the optical fiber 110, the size of the electron excitation layer 121 is 30-60μm (much larger than the diameter of the fiber core 111. In this embodiment, along the radial direction of the optical fiber 110, the size of the electron excitation layer 121 is 40μm). A copper wire with a diameter of 125 micrometers is selected as the anode target 200, with β being 30°, meaning that the direction of the reflective target surface 210 and the extension direction of the optical fiber 110 are at a 30° angle. The inner tube 310 of the tube body 300 is a beryllium hollow tube with an inner diameter of 125 micrometers, an outer diameter of 300 micrometers, and a length of 6 centimeters. The outer tube 320 is a lead hollow tube with an inner diameter of 300 micrometers, an outer diameter of 1000 micrometers, and a length of 6 centimeters. The output window 311 is square, with a length and width of 200 micrometers.

[0276] Example 3

[0277] Please see Figure 13The optical fiber 110 is a single-mode optical fiber. The diameter of the fiber core 111 of the optical fiber 110 is 8.2 μm, the diameter of the optical fiber 110 is 125 μm, and the wavelength of the laser transmitted in the optical fiber 110 is 1550 nm. The aforementioned conductive connection layer 130 is formed on the outer surface of the optical fiber 110. The conductive connection layer 130 includes 5 nm of titanium and 50 nm of gold stacked on the light-emitting end 1102 of the optical fiber 110. The fiber core 111 at the light-emitting end 1102 is exposed (without being covered by the conductive connection layer 130). Using the above-described steps of "transferring the electron excitation layer 121 on the temporary substrate 20 to the end face 11021 of the light-emitting end 1102 of the optical fiber 110", an auxiliary layer 122 with a thickness of 1 nm and made of graphene is formed on the end face 11021 of the light-emitting end 1102 of the optical fiber 110. Then, multiple nanotubes are deposited on the auxiliary layer 122, with the axial direction of the nanotubes parallel to the extension direction of the fiber core 111, to obtain the electron excitation layer 121, thereby obtaining the electron source 100. Among them, the first conductive portion 131 of the conductive connection layer 130 is disposed on the end face 11021 of the light-emitting end 1102 of the optical fiber 110 and overlaps with the auxiliary layer 122, and the second conductive portion 132 of the conductive connection layer 130 is disposed on the circumferential side surface of the optical fiber 110.

[0278] Comparative Example 1

[0279] An electron source was prepared according to the structure of Example 1, except that the electron excitation layer 121 in Example 1 was replaced with a gold layer with a thickness of 100 nm, and the gold layer was prepared by deposition.

[0280] Comparative Example 2

[0281] An electron source was prepared according to the structure of Comparative Example 1, except that the electron excitation layer 121 in Comparative Example 1 was replaced with a gold layer with a thickness of 1 nm.

[0282] The electron sources were prepared using the above embodiments and comparative examples. The performance of the prepared electron sources was tested, and the test results are shown in the table below:

[0283] Table 1

[0284] serial number stability life Working vacuum Example 1 1％ 2000h 10Pa Example 2 1％ 2000h 10Pa Example 3 2％ 500 h <![CDATA[10 -3 Well]]> Comparative Example 1 10％ 100 h <![CDATA[10 -5 Well]]> Comparative Example 2 20％ 20 h <![CDATA[10 -5 Well]]>

[0285] Stability refers to the condition where the excitation power of the electron source is 50% or more of the damage power and the vacuum degree is 2×10⁻⁶. -5 At a given Pa, after continuous emission for 1 hour and removal of defective points, the ratio of the difference between the maximum and minimum currents to the average current represents stability. Stability reflects the operational stability of the electron source. Lifetime refers to the period when the excitation power of the electron source is 50% or more of the damage power and the vacuum level is 2 × 10⁻⁶. -5At a given Pa, the continuous emission current continues until it decays to less than 10% of its initial value; this period is defined as the lifetime. The operating vacuum level refers to the continuous emission current when the excitation power of the electron source is 50% or more of the damage power. The vacuum level gradually increases until the current exhibits rapid decay (rapid decay is defined as the current decaying by more than 50% within one minute). The vacuum level at this point is defined as the operating vacuum level. As can be seen from the table above, the electron source of this application has good stability, a long lifetime, and a superior operating vacuum level.

[0286] Tests revealed that the electronic sources prepared using Examples 1-3 had a longer lifespan compared to those prepared using the comparative example; and the electronic sources prepared using Examples 1-3 had better stability compared to those prepared using the comparative example.

[0287] In summary, the low-dimensional materials in this application, such as zero-dimensional, one-dimensional, and two-dimensional materials, possess atomic-level dimensions. Back-incidence electrons can be emitted into the vacuum without bulk transmission, making them ideal for ultrafast electron sources with narrow pulse widths. Furthermore, low-dimensional materials can be directly integrated with different types of optical fibers, resulting in ultra-high stability and integration. In addition, low-dimensional materials are free of dangling bonds, are stable, have high melting points, and are not easily damaged, making them suitable for high-power, high-current electron sources. Integration of low-dimensional materials with tips yields extremely sharp fiber tips with large optical and electric field enhancement factors, providing a large emission beam. Numerous combinations of low-dimensional materials are suitable for photoelectron sources with various properties. Finally, fiber-integrated low-dimensional material electron sources and low-dimensional material integration offer significant advantages. Optical fibers not only transmit laser light but also serve as carriers for low-dimensional materials, providing a stable excitation source with tunable wavelength, polarization, and optical modes, applicable to various application scenarios. They eliminate the need for complex optical paths, are small in size, and have high integration density. When integrated with other devices, stable integration can be achieved without disruptive modifications to vacuum electronic equipment.

[0288] Compared to X-ray tubes in related technologies that use a grid structure as the accelerating electrode, in this application, there is a preset electric field between the anode target 200 and the electron excitation layer 121, which allows electrons emitted from the electron excitation layer 121 to be emitted towards the anode target 200 along the extension direction of the optical fiber 110 under the action of the preset electric field. This saves space in the vacuum chamber 301, simplifies the optical and electrical systems, and makes it easier to form an integrated and miniaturized X-ray tube 10.

[0289] Compared to traditional X-ray tubes, a portion of the inner tube 310 of the tube body 300 in this application serves as the output window 311, which simplifies the window structure to the greatest extent and is more conducive to miniaturizing the X-ray tube 10. In addition, unlike the relatively macroscopic and complex mechanical structures in the prior art, this solution adopts a highly integrated fiber optic structure, which reduces the existing centimeter-scale small X-ray source to the micrometer scale while ensuring that the power difference is not significant.

[0290] By assembling the electron source 100 and the anode target 200 inside the tube 300 with a smaller diameter, the electron excitation layer 121 and the anode target 200 can accelerate electrons well in the smaller vacuum chamber 301. This is beneficial for achieving a high degree of integration and miniaturization of the electron source 100 and the X-ray emission structure, and helps to realize the portable application of the X-ray tube 10 and metal flaw detection in confined spaces.

[0291] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0292] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An X-ray tube, characterized in that, include: The tube body has a vacuum chamber inside; An electron source includes an optical fiber and an electron emitting layer. The light-emitting end of the optical fiber is located in the vacuum chamber. The electron emitting layer is disposed at the light-emitting end of the optical fiber, and the electron emitting layer includes at least an electron excitation layer. The electron excitation layer is disposed on the light-emitting path of the laser emitted from the optical fiber, so that the electron excitation layer can emit electrons under the excitation of the laser. as well as An anode target is disposed within the vacuum chamber, and the anode target is positioned opposite and spaced apart from the light-emitting end of the optical fiber. The anode target is used to receive electrons emitted from the electron-excited layer in order to emit X-rays. The tube body is provided with an output window facing the anode target, and the output window is configured to guide the X-rays out of the vacuum chamber. The electron excitation layer includes at least one of zero-dimensional materials, one-dimensional materials, and two-dimensional materials; The electrons in the electron excitation layer can absorb photons from the laser, so that the electron excitation layer can emit electrons under the excitation of the laser. Low-dimensional materials include zero-dimensional, one-dimensional, or two-dimensional materials; low-dimensional materials are integrated with optical fibers. The optical fiber includes a core for transmitting laser light and a cladding layer wrapped around the core. The light-emitting end of the optical fiber has a light-leaking notch constructed along the radial direction of the optical fiber; The electron emission layer is disposed on the bottom wall surface of the light leakage notch, the bottom wall surface of the light leakage notch is constructed as a plane, and the projection of the electron excitation layer on the bottom wall surface covers the projection of the fiber core on the bottom wall surface; The electron excitation layer also extends to the light-emitting end of the optical fiber.

2. The X-ray tube according to claim 1, characterized in that, Along the extension direction of the optical fiber, the electron source and the anode target are spaced apart; The anode target has a reflective target surface facing the light-emitting end, and the reflective target surface is set at an angle to the extension direction of the optical fiber; The output window is located on the side wall of the tube and faces the reflective target surface.

3. The X-ray tube according to claim 1, characterized in that, The anode target includes a transmission anode; Along the longitudinal extension direction of the tube, the electron source and the output window are located at opposite ends of the tube, and the transmission anode is located between the electron source and the output window.

4. The X-ray tube according to any one of claims 1-3, characterized in that, Along the extension direction of the optical fiber, the anode target is spaced apart from the light-emitting end of the optical fiber, and a preset electric field exists between the anode target and the electron excitation layer, so that the electrons emitted from the electron excitation layer can be accelerated linearly along the extension direction of the optical fiber.

5. The X-ray tube according to claim 4, characterized in that, The electron source further includes a conductive connection layer, which is disposed at least at the light-emitting end of the optical fiber and is electrically connected to the electron excitation layer.

6. The X-ray tube according to any one of claims 1-3, characterized in that, The tubes are respectively fitted onto the optical fiber and the anode target.

7. The X-ray tube according to claim 6, characterized in that, The tube has a first port that communicates with the vacuum chamber; The light-emitting end of the optical fiber extends into the vacuum chamber through the first port, and the outer peripheral wall of the optical fiber is sealed to the inner peripheral wall of the first port.

8. The X-ray tube according to claim 7, characterized in that, The tube body also has a second port disposed opposite to the first port, and the side of the anode target away from the light-emitting end extends out of the vacuum chamber through the second port; The outer peripheral wall of the anode target is sealed to the inner peripheral wall of the second port.

9. The X-ray tube according to claim 8, characterized in that, The X-ray tube also includes an external electrode, which is disposed between the outer peripheral wall of the anode target and the inner peripheral wall of the second port; Along the longitudinal extension direction of the tube, one end of the external electrode is located inside the vacuum chamber, and the other end extends out of the vacuum chamber.

10. The X-ray tube according to claim 7, characterized in that, The optical fiber has an input end disposed opposite to the output end, and the end face of the input end is flush with the plane of the first port; or The light-input end extends out of the vacuum chamber through the first port.

11. The X-ray tube according to claim 6, characterized in that, The tube body includes an inner tube sleeved on the optical fiber and the anode target, and an outer tube sleeved on the inner tube. The outer tube has an opening, through which part of the structure of the inner tube is exposed to form the output window. The inner tube is made of an X-ray transmitting material, and the outer tube is made of an X-ray blocking material.

12. The X-ray tube according to claim 6, characterized in that, The outer diameter of the tube is 125μm-2000μm, and the length of the tube is 3cm-9cm.

13. The X-ray tube according to any one of claims 1-3, characterized in that, The thickness of the electron excitation layer is less than or equal to 50 nm.

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