Spherical glass x-ray tube

Abstract

The application discloses a spherical glass X-ray tube, and relates to the technical field of X-ray tubes, which comprises a spherical glass shell, a cathode assembly, an anode assembly and an integrated mounting structure; a vacuum sealed cavity is formed in the spherical glass shell, and the cathode assembly and the anode assembly are respectively sealed and fixed at opposite ends of the spherical glass shell; the cathode assembly comprises a filament, a cathode cover and an electron beam cover, the filament is located in the cathode cover, and the electron beam cover is arranged at the front end of the cathode cover and used for focusing an electron beam; the anode assembly comprises an anode target and a support body, a target surface of the anode target faces the cathode assembly, and the support body is in thermal connection with the anode target; the integrated mounting structure comprises a tube mounting flange sleeve, a tube mounting sealing ring and a tube mounting fastening hole, and the tube mounting flange sleeve is fixed around the outside of the spherical glass shell. The application has the effects of effectively preventing the breakage and chronic air leakage of the glass shell and ensuring the long-term maintenance of high vacuum degree.

Description

Technical Field

[0001] This invention relates to the technical field of X-ray tubes, and in particular to a spherical glass X-ray tube. Background Technology

[0002] X-ray tubes are the core components that generate X-rays and are widely used in medical diagnosis, industrial non-destructive testing, security inspection, scientific research, and other fields. Traditional mainstream X-ray tubes typically adopt a metal-ceramic structure, which consists of a metal tube base encapsulating a cathode (filament) and an anode (target), and is insulated and vacuum-sealed by a ceramic ring.

[0003] Existing X-ray tubes are mainly divided into two categories: one is the mainstream metal-ceramic structure, which encapsulates the cathode (filament) and anode (target) with a metal tube seat and achieves insulation and vacuum sealing through a ceramic ring; the other is the glass shell X-ray tube, which mostly adopts a cylindrical or other irregular shape structure, directly using the glass shell as the mounting reference surface and sealing surface, without the need for additional metal tube seat for auxiliary fixation. Both types of structures are designed around the core principle of "electron emission - acceleration - bombardment of the target to generate X-rays".

[0004] Existing glass X-ray tubes have insufficient mechanical reliability. After vacuuming, the atmospheric pressure on different parts of the irregularly shaped glass shell or metal-ceramic interface is uneven, and stress is concentrated at the corners, transition areas or sealing points, which can easily cause micro-cracks or chronic air leakage, seriously affecting the life of the device and vacuum stability. Summary of the Invention

[0005] This application provides a spherical glass X-ray tube that effectively prevents the glass shell from cracking and causing chronic gas leakage, ensuring the long-term maintenance of a high vacuum.

[0006] This application provides a spherical glass X-ray tube, which adopts the following technical solution: A spherical glass X-ray tube includes a spherical glass shell, a cathode assembly, an anode assembly, and an integrated mounting structure. The spherical glass shell forms a vacuum-sealed cavity. The cathode assembly and the anode assembly are respectively sealed and fixed at opposite ends of the spherical glass shell. The cathode assembly includes a filament, a cathode cover, and an electron beam cover. The filament is located inside the cathode cover, and the electron beam cover is positioned at the front end of the cathode cover for focusing the electron beam. The anode assembly includes an anode target and a support. The target surface of the anode target faces the cathode assembly, and the support is thermally connected to the anode target. The integrated mounting structure includes a X-ray tube mounting flange, a X-ray tube mounting sealing ring, and a X-ray tube mounting fastening hole. The X-ray tube mounting flange is fixed around the outside of the spherical glass shell. The X-ray tube mounting sealing ring is located between the X-ray tube mounting flange and the spherical glass shell to achieve a vacuum seal. The X-ray tube mounting fastening hole is located on the X-ray tube mounting flange for fixing to external equipment.

[0007] Preferably, the electron beam cover and the cathode cover are coaxially arranged, and the two together define the electron focusing cavity, with the filament located at the focal point of the electron focusing cavity.

[0008] Preferably, the electron focusing cavity is a closed annular electric field confinement space, and the inner wall of the electron beam cover and the outer wall of the cathode cover are spaced apart to form an electric field focusing channel.

[0009] Preferably, the radial distances between the inner wall of the spherical glass shell and each fixed point of the cathode and anode components are equal, and the cathode and anode components are symmetrically distributed along the central axis of the spherical glass shell.

[0010] Preferably, the support body is in direct contact with the ray tube mounting flange or in close contact through a heat-conducting medium, and the contact surface between the support body and the ray tube mounting flange is provided with a heat-conducting filling structure to eliminate gaps.

[0011] Preferably, the thermally conductive medium is a composite filler layer formed by a mixture of thermally conductive silicone grease and copper powder, and the thickness of the composite filler layer is between 0.1 mm and 0.5 mm.

[0012] Preferably, the bottom of the X-ray tube mounting flange sleeve is provided with an annular reinforcing rib at the connection between it and the spherical glass shell, and the reinforcing rib and the X-ray tube mounting flange sleeve are integrally formed.

[0013] Preferably, the center line connecting the cathode assembly and the anode assembly passes through the geometric center of the spherical glass shell, and the electron beam transmission path coincides with the center line.

[0014] Preferably, the junction of the electron beam cover and the cathode cover is provided with an electrostatic shielding layer, which is formed into a continuous cover layer by a conductive coating process.

[0015] Preferably, the spherical glass shell has an X-ray tube window at the position corresponding to the anode target surface, and the X-ray tube window is made of a metal composite material with higher X-ray transmittance than conventional glass.

[0016] In summary, this application has the following beneficial effects: 1. The use of a spherical glass shell ensures uniform stress distribution at all points after vacuuming, greatly eliminating stress concentration points and effectively preventing glass shell breakage and chronic leakage, thus ensuring the long-term maintenance of high vacuum.

[0017] 2. The spherical structure optimizes and uniformly distributes the insulation distance between the internal high-voltage electrode and the inner wall of the glass shell, resulting in an ideal electric field distribution. This reduces the risk of partial discharge and high-voltage breakdown, allowing the X-ray tube to operate stably at higher voltages.

[0018] 3. Within a spherically symmetrical space, the electron optical system composed of the cathode cover and the electron beam cover can more effectively confine and focus electrons, forming a focused spot with concentrated energy and small size, which is beneficial to improving the X-ray output quality and imaging resolution.

[0019] 4. The heat generated by the anode target is directly conducted to the external mounting flange through the support body, and then transferred to the equipment cooling system from the flange. This path has low thermal resistance and strong heat dissipation capacity. At the same time, the spherical shell also provides auxiliary heat dissipation area, significantly reducing the operating temperature of the anode target and allowing for larger tube currents and continuous operating loads.

[0020] 5. Connection and sealing with external equipment are achieved through independent metal mounting flange sleeves and sealing rings, completely transferring installation stress and sealing pressure from the brittle glass shell to the robust metal flange, which protects the glass shell and enables more reliable and easier-to-maintain modular installation.

[0021] 6. To address the issues of uneven stress and electric field distortion in the glass shell of existing technologies, and to further optimize mechanical reliability and high-voltage adaptability, this invention also incorporates a spherical glass shell, which forms a vacuum-sealed cavity. The cathode and anode components are symmetrically fixed at opposite ends along the central axis, with equal radial distances between the inner wall and each fixed point of the components. This achieves uniform stress distribution and an ideal electric field distribution at all points of the shell, eliminating stress concentration, reducing the risk of high-voltage breakdown, and ensuring long-term maintenance of high vacuum.

[0022] 7. To address the issues of electron beam scattering and poor focusing, and to further optimize X-ray output quality and imaging resolution, this invention also includes a cathode assembly consisting of a filament, a cathode cover, and an electron beam cover. The filament is located inside the cathode cover, and the electron beam cover is located at the front end of the cathode cover and is coaxially positioned, together defining the electron focusing cavity. This achieves efficient confinement and precise focusing of the electron beam, forming a small-sized electron beam focal point with concentrated energy, laying the foundation for high-quality X-ray generation.

[0023] 8. In order to solve the problems of severe heat accumulation and low heat dissipation efficiency of the anode target, and to further optimize the continuous working load and target life of the device, the present invention also provides an anode assembly including an anode target and a support. The anode target surface faces the cathode assembly, and the support is thermally connected to the anode target to achieve the effect of rapid heat conduction, dissipating a large amount of heat from the target surface, avoiding overheating and evaporation of the target material, and breaking through the power limitation.

[0024] 9. To address the issues of installation stress damaging the glass and poor sealing reliability, and to further optimize modular installation and vacuum sealing performance, this invention also incorporates an integrated installation structure consisting of a flange sleeve, a sealing ring, and fastening holes. The flange sleeve is fixed around the outside of the spherical glass shell, the sealing ring achieves vacuum sealing, and the fastening holes are used to fix it to external equipment. This achieves the effect of transferring installation stress and sealing pressure to the metal flange, protecting the glass shell from damage, while improving the convenience of installation and maintenance and the stability of the seal. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the spherical glass X-ray tube in this embodiment; Figure 2 This is an overall cross-sectional view of the spherical glass X-ray tube in this embodiment; Figure 3 This is a front cross-sectional view of the spherical glass X-ray tube in this embodiment; Explanation of reference numerals in the attached drawings: 1. Spherical glass shell; 2. Cathode assembly; 21. Filament; 22. Cathode cover; 23. Electron beam cover; 3. Anode assembly; 31. Anode target; 32. Support body; 33. Target surface; 4. Integrated mounting structure; 41. X-ray tube mounting flange; 42. X-ray tube mounting sealing ring; 43. X-ray tube mounting fastening hole; 5. X-ray tube window. Detailed Implementation

[0026] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content. Example

[0027] This invention discloses a spherical glass X-ray tube, which has the advantages of high mechanical strength, excellent electric field distribution, good heat dissipation, reliable installation and sealing, and long service life. Figure 1 As shown, it includes a spherical glass shell 1, a cathode assembly 2, an anode assembly 3, and an integrated mounting structure 4.

[0028] like Figure 1As shown, the interior of the spherical glass shell 1 forms a vacuum-sealed cavity for the X-ray tube. This vacuum-sealed cavity is a necessary prerequisite for the operation of the X-ray tube. The vacuum environment completely isolates air molecules, preventing energy loss and ionization scattering caused by collisions between electrons emitted by the cathode filament 21 and gas molecules during transmission. Simultaneously, it ensures the insulation of the cavity under high-voltage operating conditions, preventing localized electrical breakdown. Furthermore, the spherical geometry ensures uniform stress distribution within the cavity, eliminating stress concentration points and maintaining a long-term vacuum seal, providing a stable physical environment for electron movement. The cathode assembly 2 and anode assembly 3 are respectively sealed and fixed at opposite ends inside the spherical glass shell 1. This ensures a straight electron beam transmission path, avoiding electron dissipation caused by the bending of traditional structures.

[0029] like Figure 2 As shown, the cathode assembly 2 includes a filament 21, a cathode cover 22, and an electron beam cover 23. The filament 21 is located inside the cathode cover 22, and the electron beam cover 23 is positioned in front of the cathode cover 22 to focus electrons emitted from the filament 21, forming a focused electron beam. The filament 21 generates free electrons through thermal excitation. The cathode cover 22 constrains the electron emission range, reducing initial dissipation. The electron beam cover 23 in front uses an electric field to focus the divergent electrons into a highly concentrated focused electron beam. Furthermore, the centrally symmetrical uniform electric field within the spherical cavity further assists in focusing, correcting the electron trajectory and avoiding focusing deviation caused by local electric field distortion. Ultimately, this achieves full controllability of the electron beam from emission to focusing, laying a highly efficient electron source foundation for X-ray generation on the anode target 31.

[0030] First, the high concentration of the focused electron beam combined with a linear transmission path results in a smaller and more fixed point of impact on the anode target 31, significantly improving the energy concentration and collimation of the X-ray emission. In medical imaging and industrial non-destructive testing, this significantly enhances imaging resolution and the accuracy of detecting minute defects, overcoming the accuracy bottleneck caused by electron dissipation in traditional X-ray tubes. Second, the spherical uniform electric field, combined with the focusing effect of the electron beam cover 23, greatly reduces stray electron generation. This improves electron utilization, reduces overall tube energy consumption, and avoids partial discharge and glass aging caused by stray electrons impacting the inner wall of the glass shell, indirectly extending the service life of the spherical glass shell 1. Furthermore, the spherical vacuum cavity has strong sealing stability, maintaining a high vacuum level for extended periods. This prevents air molecules from entering the cavity and reacting with the high-temperature filament 21, causing oxidation and sputtering reactions. This effectively avoids filament 21 wear, ensuring long-term stability of its thermal emission efficiency, reducing X-ray dose decrease due to emission efficiency decay, and lowering the replacement frequency of the filament 21. Finally, the sealing and fixing method of the cathode assembly 2 and the spherical glass shell 1 at opposite ends ensures that the deformation of the cathode is evenly distributed along the spherical surface when the cathode expands and contracts during operation. The relative positions of the filament 21, cathode cover 22 and electron beam cover 23 are not easily shifted, which ensures the long-term accuracy of the focusing structure. It eliminates the need for frequent calibration of focusing parameters and greatly reduces the frequency and cost of later maintenance of the equipment.

[0031] like Figure 2 and Figure 3 As shown, the anode assembly 3 includes an anode target 31 and a support 32. The target surface 33 of the anode target 31 faces the cathode assembly 2 and is used to receive the bombardment of the focused electron beam to generate X-rays. The support 32 is thermally connected to the anode target 31 and conducts heat away. Based on the spherical vacuum sealed cavity, the target surface 33 of the anode target 31 is precisely oriented towards the cathode assembly 2, matching the fixed layout of the cathode and anode at opposite ends of the spherical shell. This ensures that the focused electron beam emitted by the cathode can be transmitted in a straight line and bombard the target surface 33 vertically and efficiently. Based on the principle of bremsstrahlung and characteristic radiation of electron beam bombardment of metal target material, the kinetic energy of electrons is converted into X-rays to the maximum extent, reducing energy loss caused by electron beam deflection. Meanwhile, when the anode target 31 receives electron beam bombardment, only a small amount of energy is converted into X-rays, and the vast majority of energy is converted into heat. If heat accumulates, it will cause the target surface 33 to ablate and its performance to degrade. Therefore, the anode target 31 and the support 32 adopt a thermal connection design. Through metal heat conduction, the heat on the anode target 31 is quickly transferred to the support 32, and then the support 32 conducts the heat to the outside of the spherical glass shell 1, forming an efficient heat dissipation path of "anode target 31-support 32-outside". Combined with the heat dissipation advantages of the spherical shell, the industry pain point of anode overheating is solved from a structural point of view, ensuring the continuous and stable operation of the X-ray tube.

[0032] Furthermore, firstly, the direct-facing design of the anode target 31 with its surface facing the cathode ensures that the focused electron beam bombards the target surface 33 perpendicularly. This significantly reduces oblique reflection of the electron beam, lowers the probability of stray electrons impacting the inner wall of the spherical glass shell 1, and prevents the glass shell from aging due to ion sputtering caused by electron bombardment. This further maintains the sealing performance of the vacuum chamber and extends the vacuum holding time of the entire tube. Secondly, the thermal connection design between the anode target 31 and the support 32 ensures more uniform heat dissipation, preventing localized overheating and thermal deformation of the anode target 31. This guarantees the flatness of the target surface 33, ensuring that the target point bombarded by the electron beam remains fixed. This ensures high stability in the direction, dose, and energy spectrum of X-ray emission, improving the repeatability and accuracy of detection results in medical imaging and industrial testing.

[0033] like Figure 2 and Figure 3 As shown, the integrated installation structure 4 includes a X-ray tube mounting flange sleeve 41, a X-ray tube mounting sealing ring 42, and a X-ray tube mounting fastening hole 43. The X-ray tube mounting flange sleeve 41 surrounds and is fixedly connected to the bottom outer side of the spherical glass shell 1. Its inner ring is vacuum sealed to the outer wall of the spherical glass shell 1 through the X-ray tube mounting sealing ring 42. The X-ray tube mounting fastening hole 43 is provided on the X-ray tube mounting flange sleeve 41 and is used to modularly fix the entire X-ray tube to the external equipment and conduct the heat generated by the anode assembly 3 to the external heat dissipation system.

[0034] The X-ray tube mounting flange 41, as the core load-bearing component, surrounds and is fixed to the outer bottom of the spherical glass shell 1. Adapting to the curvature of the spherical surface, it achieves a tight fit, providing stable mounting support for the entire X-ray tube and serving as a bridge between the tube body and external equipment. The X-ray tube mounting sealing ring 42 is responsible for vacuum sealing. It fits tightly against the inner ring of the flange and the outer wall of the spherical glass shell 1, filling the tiny gap between them. Together with the vacuum cavity inside the spherical glass shell 1, it forms a double vacuum seal, preventing external air from entering the tube body and disrupting the vacuum environment, thus ensuring the normal operation of the cathode and anode components 3.

[0035] The X-ray tube mounting fastening hole 43 is key to modular fixation. Through the fastener through the hole, the X-ray tube is fixed to the external equipment as a whole, realizing modular installation. At the same time, the flange sleeve is made of a material with excellent thermal conductivity, which can quickly absorb the heat conducted from the anode assembly 3 to the spherical glass shell 1. It also connects to the external heat dissipation system through the fastening hole, forming a complete heat dissipation closed loop of "anode assembly 3-spherical glass shell 1-flange sleeve-external heat dissipation system", further optimizing the heat dissipation effect of the entire tube.

[0036] First, the design of the X-ray tube mounting flange 41 surrounding the bottom of the spherical glass shell 1 not only serves an installation function but also forms a ring reinforcement at the bottom of the spherical glass shell 1, further dispersing the stress on the spherical shell and preventing localized stress concentration at the bottom due to installation forces. This indirectly strengthens the mechanical strength of the spherical glass shell 1 and reduces the risk of cracking due to improper installation. Furthermore, the modular installation design allows the X-ray tube to be disassembled and replaced as a whole without disassembling the core components of external equipment, significantly shortening the maintenance and replacement cycle, reducing maintenance difficulty, and preventing damage to the tube's vacuum seal and component positions during maintenance, thus improving equipment operation and maintenance efficiency. Second, the fitting design of the X-ray tube mounting sealing ring 42 with the flange and spherical glass shell 1 not only achieves a vacuum seal but also buffers vibrations generated during the operation of external equipment, reducing vibration transmission to the interior of the spherical glass shell 1. This prevents the cathode and anode components 3 from shifting positions, ensuring electron beam focusing accuracy and X-ray output stability. Finally, the flange sleeve has both heat conduction and fixing functions. While conducting heat, it can balance the temperature at the bottom of the tube, avoid aging of the outer wall of the spherical glass shell 1 due to local high temperature, and reduce the load on the external heat dissipation system and reduce the energy consumption of the external heat dissipation equipment. In addition, the standardized layout of the fastening holes can be adapted to a variety of external equipment, improving the versatility of the X-ray tube and breaking the limitation of poor installation adaptability of traditional X-ray tubes.

[0037] like Figure 2 and Figure 3 As shown, the central region of the spherical glass shell 1 is the electron acceleration zone between the cathode assembly 2 and the anode assembly 3. The distance between the inner wall of the spherical glass shell 1 and each point of the cathode assembly 2 and the anode assembly 3 is uniform. Setting the central region of the spherical glass shell 1 as the electron acceleration zone, and ensuring the uniform distance between the inner wall and each point of the cathode and anode assemblies 3, essentially utilizes the "equidistant" characteristic of a sphere to precisely and symmetrically arrange the anode and cathode assemblies 3 on both sides of the sphere's center, ensuring the electron acceleration path is at the geometric center of the sphere. From the perspective of the electron acceleration mechanism, after the focused electron beam emitted by the cathode assembly 2 enters the central acceleration zone, due to the symmetrical distribution of the anode and cathode, the electric field lines in the acceleration zone are uniformly radially distributed around the center of the sphere. Under the action of the electric field force, the electrons accelerate uniformly along a straight line, avoiding the electric field distortion and excessively high local field strength problems caused by asymmetrical structures. Simultaneously, the uniform distance between the inner wall and each point of the assembly ensures that the distance between the electrons and the inner wall of the glass shell remains consistent throughout the acceleration process. This prevents electrical breakdown caused by excessively close local distances and reduces electron trajectory deviation, ensuring the electron beam accurately bombards the anode target 31. Furthermore, the uniform distance distribution makes the vacuum environment in the acceleration zone more stable, reduces local gas residue, reduces collision losses between electrons and gas molecules, ensures the efficient conversion of electron kinetic energy into X-rays, and provides geometric support for the overall mechanical strength and heat dissipation performance, which aligns with the core advantages of the aforementioned spherical glass tube.

[0038] First, the uniform distance between the inner wall and all points of the component ensures that the electric field force, indirect effects of electron bombardment, and thermal radiation intensity experienced by all points on the inner wall of the glass shell are completely consistent. This avoids aging and cracking of the glass material caused by uneven local stress and heating, significantly extending the service life of the glass shell and reducing the risk of vacuum seal failure. Second, the symmetrical electric field in the central acceleration region can automatically correct for minor electron beam deviations. Even with slight installation deviations at the cathode and anode, the uniform electric field can guide the electron beam to the precise position on the target surface 33, reducing the component installation accuracy requirements and decreasing the difficulty and cost of production and assembly.

[0039] Subsequently, the uniform spacing ensures a balanced electric field shielding effect on the inner wall of the glass shell, effectively resisting external electromagnetic interference and reducing electromagnetic radiation from the internal electric field to external equipment. This improves the electromagnetic compatibility of the X-ray tube, making it suitable for complex scenarios such as high-precision medical imaging and industrial non-destructive testing. Finally, the symmetrical layout of the central accelerating region and the anode and cathode ensures uniform heat radiation distribution within the tube, preventing localized high temperatures and thermal stress. This further enhances the overall mechanical stability of the tube, enabling it to operate stably under high-voltage and high-frequency conditions for extended periods. It also assists in heat dissipation of the anode assembly 3, reducing the load on the external cooling system.

[0040] like Figure 2 and Figure 3 As shown, the support 32 and the X-ray tube mounting flange 41 are in close contact, either directly or through a heat-conducting medium, forming the main heat dissipation path from the target surface 33 to the external environment. This efficiently removes the large amount of heat generated by the anode target 31 during operation, addressing industry pain points such as performance degradation and shortened lifespan caused by anode overheating in X-ray tubes, and synergizing with the overall advantages of spherical glass X-ray tubes. When the anode target 31 receives focused electron beam bombardment, only a small amount of energy is converted into X-rays, while the vast majority is converted into heat. If heat accumulates, it can cause ablation of the target surface 33 and component deformation. Therefore, by having the support 32 in close contact with the X-ray tube mounting flange 41, either directly or through a heat-conducting medium, a main heat dissipation path is established: "target surface 33—anode target 31—support 32—flange—external environment".

[0041] The core logic is to utilize the excellent thermal conductivity of the support 32 and the flange sleeve to reduce thermal resistance during heat conduction. The heat transfer medium can further fill the contact gap between the two, eliminating heat loss caused by air gaps and allowing for rapid heat transfer. The flange sleeve, as an installation and fixing component, also serves as a heat carrier, efficiently transferring the received heat to the external heat dissipation system and environment. Compared to the traditional method of relying on indirect heat dissipation through a glass shell, this path has higher thermal conductivity and less loss, becoming the core channel for heat removal. This ensures that the anode assembly 3 operates within a reasonable temperature range for a long time, providing thermal management support for the stable operation of the X-ray tube.

[0042] First, efficient heat dissipation keeps the temperature of the anode target 31 stable, preventing grain growth and material aging on the target surface 33 due to localized overheating. This not only extends the service life of the anode target 31 but also maintains the flatness of the target surface 33, ensuring the electron beam bombardment point is fixed, guaranteeing stable X-ray output dose and energy spectrum, and improving the accuracy and consistency of detection imaging. Second, the tight contact between the support 32 and the flange sleeve, in addition to conducting heat, also enhances the installation stability of the anode assembly 3. With the fixing effect of the flange sleeve, the positional displacement of the anode assembly 3 caused by thermal expansion and contraction and equipment vibration is reduced, indirectly ensuring the relative positional accuracy of the cathode and anode and maintaining the electron beam focusing effect.

[0043] like Figure 2 and Figure 3 As shown, the electron beam cover 23 and the cathode cover 22 are coaxially arranged. This coaxial arrangement is fundamental to focusing uniformity. The coaxiality of the electron beam cover 23 and the cathode cover 22 ensures that their central axes coincide, avoiding distortion of the electric field inside the focusing cavity due to eccentricity, and forming a symmetrical and uniform focusing electric field within the cavity. Together, they define an electron focusing cavity, which is essentially a closed electric field confinement space. This space not only prevents the electrons emitted by the filament 21 from scattering randomly in all directions, but also forms a confinement force on the electrons towards the center through the electric field effect of the inner wall of the cavity. The filament 21 is located near the focal point of this electron focusing cavity. Free electrons generated by thermal excitation of the filament 21 are emitted from the focal point and, under the action of the uniform electric field of the focusing cavity, are continuously converged and accelerated along the coaxial direction, ultimately forming a focused electron beam with a small cross-section, precise direction, and concentrated energy. This beam is precisely transmitted towards the anode target 31, minimizing electron energy loss and ensuring efficient conversion of electron kinetic energy into X-rays. At the same time, it matches the uniform electric field environment of the electron acceleration zone of the spherical glass shell 1, ensuring the stability of electron beam transmission.

[0044] First, the coaxial design ensures a symmetrical and uniform electric field in the focusing cavity, effectively suppressing stray electron generation and reducing ion sputtering and material aging caused by stray electrons impacting the inner wall of the spherical glass shell 1. This delays glass shell wear and prevents stray electrons from interfering with the vacuum environment inside the tube, indirectly extending the service life of the vacuum-sealed cavity. Second, the filament 21 is located near the focal point of the focusing cavity, significantly improving electron beam focusing accuracy and resulting in a smaller electron beam cross-section. This significantly reduces the target area bombarding the anode target 31, reducing localized ablation of the anode target 31, extending anode lifespan, and improving X-ray collimation and energy spectrum uniformity, thus optimizing the accuracy and consistency of medical imaging and industrial testing. Third, the confinement effect of the focusing cavity and the stability of the coaxial structure limit the heat generated by the filament 21 during operation to the inside of the focusing cavity, reducing heat conduction to the spherical glass shell 1 and preventing localized overheating and thermal stress. This also reduces the overall temperature difference inside the tube, further enhancing the overall mechanical stability of the tube. Fourth, the coaxial arrangement reduces the difficulty of component assembly. It can ensure the relative position accuracy of electron beam cover 23 and cathode cover 22 without complex positioning, reducing production assembly errors and manufacturing costs. At the same time, when thermally expanding and contracting, the deformation of the coaxial structure is symmetrically distributed, and the relative position of filament 21 and focusing cavity is not easily shifted. It eliminates the need for frequent calibration of focusing parameters and greatly reduces the later maintenance costs of the equipment.

[0045] like Figure 3 As shown, an X-ray tube window 5 is provided on the spherical glass shell 1 corresponding to the target surface 33 of the anode target 31. This window is made of a material with high X-ray transmittance. After the target surface 33 of the anode target 31 receives the focused electron beam, it generates X-rays. However, the spherical glass shell 1 itself is made of ordinary glass, which has a strong absorption and attenuation effect on X-rays, and cannot meet the requirement of efficient X-ray emission. Therefore, the X-ray tube window 5 is set in the area of ​​the spherical glass shell 1 corresponding to the target surface 33 of the anode target 31. This allows for precise alignment with the main emission direction of X-rays, avoiding losses caused by path deviation during X-ray transmission. The window is made of a material with high X-ray transmittance, primarily to reduce the energy attenuation of X-rays during the extraction process, ensuring that most X-rays can penetrate the window and act on the detection or imaging scene. At the same time, this material must achieve a tight vacuum seal with the spherical glass shell 1 to avoid disrupting the vacuum environment of the cavity and ensure the normal operation of the cathode and anode components 3. Furthermore, the window position precisely corresponds to the target surface 33 of the anode target 31. Combined with the central symmetry characteristics of the spherical glass shell 1, the X-ray emission direction can be more concentrated, which matches the energy distribution law of the electron beam bombarding the target surface 33, further improving the utilization efficiency of X-rays and realizing the closed loop of "generation-extraction-utilization".

[0046] It is worth noting that the window precisely corresponds to the target surface 33 of the anode target 31, which limits the X-ray emission range and reduces the generation of stray rays. This avoids stray rays interfering with detection or imaging accuracy and reduces radiation loss to the inner wall of the spherical glass shell 1 and the cathode assembly 2, indirectly extending the service life of each component. In addition, high X-ray transmittance materials usually have the characteristics of high temperature resistance and radiation resistance. They can not only adapt to the high-temperature environment of the anode target 31 during operation, but also resist long-term radiation erosion by X-rays. At the same time, the sealing connection between this material and the spherical glass shell 1 is tighter, which can buffer the deformation caused by thermal expansion and contraction, avoid sealing gaps in the window area, and further enhance the sealing performance of the vacuum cavity. Secondly, the window is only set in the area corresponding to the target surface 33 of the anode target 31, without changing the overall structure of the spherical glass shell 1. This maximizes the mechanical advantages of the spherical shell and avoids stress concentration caused by large-area modifications. At the same time, the window can be miniaturized, reducing weak points in the vacuum cavity and improving the mechanical strength and impact resistance of the entire tube.

[0047] Working principle: First, the spherical glass shell 1 forms a high-vacuum sealed cavity through a sealing process. This is the basic premise for the operation of the X-ray tube. The vacuum environment can completely isolate air molecules, preventing the electrons emitted by the cathode filament 21 from colliding with gas molecules during transmission and causing energy loss and ionization scattering. At the same time, it ensures the insulation of the cavity under high-voltage working conditions and prevents local electrical breakdown. The flange sleeve in the integrated installation structure 4 is fixed around the outside of the spherical glass shell 1. The sealing ring is tightly attached to the inner ring of the flange sleeve and the outer wall of the glass shell, filling the tiny gaps and further enhancing the vacuum sealing effect, preventing external air from entering and disrupting the vacuum environment.

[0048] Then, the cathode assembly 2 starts working. The filament 21 generates free electrons through thermal excitation. The cathode cover 22 initially constrains the electron emission range and reduces initial dissipation. Since the electron beam cover 23 and the cathode cover 22 are coaxially arranged, they together define a closed annular electric field constraint space, forming an electric field focusing channel. The filament 21 is located at the focal point of the electron focusing cavity. Under the action of the electric field force, the divergent electrons are quickly converged to form a focused electron beam with concentrated energy and precise direction, laying the foundation for subsequent electron acceleration and bombardment of the anode target 31.

[0049] Subsequently, the cathode assembly 2 and the anode assembly 3 are symmetrically distributed along the central axis of the spherical glass shell 1. The line connecting their centers passes through the geometric center of the spherical glass shell 1, and the electron beam transmission path coincides with this central line. After the focused electron beam enters the acceleration zone at the center of the spherical glass shell 1, it is accelerated uniformly in a straight line under the action of the high voltage electric field between the cathode and anode. Thanks to the equidistant characteristics of the spherical glass shell 1, the radial distance between the inner wall and each fixed point of the cathode and anode assembly 3 is equal. The electric field lines in the acceleration zone are uniformly distributed radially with the center of the sphere as the center, avoiding local electric field distortion. This prevents electrical breakdown caused by excessive distance and reduces electron trajectory deviation, ensuring that the electron beam accurately bombards the target surface 33 of the anode target 31 with stable kinetic energy.

[0050] Next, after receiving the focused electron beam bombardment, the anode target 31 converts some of the electron kinetic energy into X-rays based on the principles of bremsstrahlung and characteristic radiation of electron beam bombardment of metal targets, while the vast majority of the remaining energy is converted into heat. The support 32, which is thermally connected to the anode target 31, quickly absorbs this heat and efficiently conducts it to the external flange through direct contact or close contact with the heat-conducting medium. The heat is then transferred from the flange to the cooling system of the external equipment, forming a complete heat dissipation path of "anode target 31 - support 32 - flange - external cooling system". This significantly reduces the operating temperature of the anode target 31, prevents the target surface 33 from being ablated and its performance from degrading, and ensures the continuous and stable operation of the device.

[0051] Meanwhile, the spherical glass shell 1 has an X-ray exit window at the position corresponding to the target surface 33 of the anode target 31. This window is made of a metal composite material with higher X-ray transmittance than conventional glass, which can reduce energy attenuation during the X-ray extraction process and allow most X-rays to penetrate the window and act on target scenarios such as medical imaging and industrial inspection. The electrostatic shielding layer set at the junction of the electron beam cover 23 and the cathode cover 22 is formed by a conductive coating process to form a continuous covering layer, which can effectively resist external electromagnetic interference, reduce the electromagnetic radiation of the electric field inside the tube to external equipment, and improve the electromagnetic compatibility of the X-ray tube.

[0052] Finally, the fastening holes in the integrated installation structure 4 are connected by fasteners to modularly fix the entire X-ray tube to the external equipment, which not only achieves convenient installation and maintenance, but also enhances the installation stability through the annular reinforcing rib (one-piece structure) at the connection between the bottom of the flange and the spherical glass shell 1, disperses the installation stress, and avoids cracks in the brittle glass shell due to uneven stress. The synergistic effect of each component, from vacuum sealing, electron focusing acceleration, X-ray generation and extraction, to heat dissipation and mechanical fixation, forms a complete working closed loop, ensuring that the X-ray tube outputs high-quality X-rays stably for a long time under high pressure and high frequency conditions.

[0053] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A spherical glass X-ray tube, characterized in that, The assembly includes a spherical glass shell (1), a cathode assembly (2), an anode assembly (3), and an integrated mounting structure (4). The spherical glass shell (1) forms a vacuum-sealed cavity. The cathode assembly (2) and the anode assembly (3) are respectively sealed and fixed at opposite ends of the spherical glass shell (1). The cathode assembly (2) includes a filament (21), a cathode cover (22), and an electron beam cover (23). The filament (21) is located inside the cathode cover (22), and the electron beam cover (23) is positioned at the front end of the cathode cover (22) for focusing the electron beam. The anode assembly (3) includes an anode target (31) and a support (32). The target surface (33) of the anode target (31) faces the cathode assembly (2), and the support (32) is thermally connected to the anode target (31). The integrated mounting structure (4) includes a ray tube mounting flange (41), a ray tube mounting sealing ring (42), and a ray tube mounting fastening hole (43). The ray tube mounting flange (41) is fixed around the outside of the spherical glass shell (1). The ray tube mounting sealing ring (42) is located between the ray tube mounting flange (41) and the spherical glass shell (1) to achieve a vacuum seal. The ray tube mounting fastening hole (43) is located on the ray tube mounting flange (41) for fixing to external equipment.

2. The spherical glass X-ray tube according to claim 1, characterized in that, The electron beam cover (23) and the cathode cover (22) are coaxially arranged, and together they define the electron focusing cavity. The filament (21) is located at the focal point of the electron focusing cavity.

3. The spherical glass X-ray tube according to claim 2, characterized in that, The electron focusing cavity is a closed annular electric field confinement space, and the inner wall of the electron beam cover (23) and the outer wall of the cathode cover (22) are spaced apart to form an electric field focusing channel.

4. The spherical glass X-ray tube according to claim 1, characterized in that, The radial distance between the inner wall of the spherical glass shell (1) and each fixed point of the cathode assembly (2) and anode assembly (3) is equal. The cathode assembly (2) and anode assembly (3) are symmetrically distributed along the central axis of the spherical glass shell (1).

5. The spherical glass X-ray tube according to claim 1, characterized in that, The support (32) is in direct contact with the ray tube mounting flange (41) or in close contact through a heat-conducting medium. The contact surface between the support (32) and the ray tube mounting flange (41) is provided with a heat-conducting filling structure to eliminate gaps.

6. The spherical glass X-ray tube according to claim 5, characterized in that, The thermally conductive medium is a composite filler layer formed by a mixture of thermally conductive silicone grease and copper powder, and the thickness of the composite filler layer is between 0.1 mm and 0.5 mm.

7. The spherical glass X-ray tube according to claim 1, characterized in that, The bottom of the ray tube mounting flange sleeve (41) is provided with an annular reinforcing rib at the connection between it and the spherical glass shell (1). The reinforcing rib and the ray tube mounting flange sleeve (41) are integrally formed.

8. The spherical glass X-ray tube according to claim 1, characterized in that, The center line connecting the cathode assembly (2) and the anode assembly (3) passes through the geometric center of the spherical glass shell (1), and the electron beam transmission path coincides with the center line.

9. The spherical glass X-ray tube according to claim 1, characterized in that, The junction of the electron beam cover (23) and the cathode cover (22) is provided with an electrostatic shielding layer, which is formed into a continuous covering layer by a conductive coating process.

10. The spherical glass X-ray tube according to claim 1, characterized in that, The spherical glass shell (1) is provided with an X-ray tube window (5) at the position corresponding to the target surface (33) of the anode target (31). The X-ray tube window (5) is made of a metal composite material with higher X-ray transmittance than conventional glass.

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