Vacuum integrated manufacturing device and method for photomultiplier tube based on laser sealing

Abstract

This invention relates to the field of photomultiplier tube technology, specifically to a vacuum integrated manufacturing apparatus and method for photomultiplier tubes based on laser sealing. The apparatus includes: a vacuum chamber equipped with a temperature control system for controlling the temperature of the chamber interior and an atmosphere system for controlling the atmosphere within the chamber; and a first tooling component including a first driving structure, a rotary table, and a first shielding cover connected to the first driving structure. This invention ensures accurate alignment of the entire tube weld seam through a rational layout of the alkali source assembly, optical window assembly, and die assembly, and independently designs the transfer method and actions. Furthermore, from baking and degassing, synchronous activation of the photocathode and dynode, to final laser sealing, all core processes are continuously completed in the same vacuum environment and in a single clamping operation. This effectively achieves integrated transfer activation and vacuum laser welding degassing of the photomultiplier tube, thereby maximizing the vacuum life, stability, and reliability of the photomultiplier tube.

Description

Technical Field

[0001] This invention relates to the field of photomultiplier tube technology, and more specifically to a vacuum integrated manufacturing apparatus and method for photomultiplier tubes based on laser sealing. Background Technology

[0002] The manufacturing process of photomultiplier tubes has always revolved around the core challenge of establishing and maintaining a long-term stable high-vacuum environment inside the device. Initially, the industry generally adopted a traditional process of separate equipment and steps, dispersing key processes such as baking and degassing, optical coating, photocathode preparation, and final sealing into multiple independent devices. While this approach allowed for specialization of each process, its fatal flaw was that the core component inevitably became exposed to the atmosphere during transfer between different chambers, leading to surface contaminant adsorption. These contaminants were slowly released during subsequent device operation, severely degrading cathode performance, accelerating vacuum degradation, and becoming a bottleneck restricting product reliability and lifespan.

[0003] To overcome this bottleneck, the industry has proposed integrated solutions, such as the device disclosed in publication number CN111261475A, which marks an important advancement in process integration. This type of device integrates multiple processes into one system through the classic design of bell jar + rotating station, effectively avoiding the exposure of workpieces to the atmosphere, and mainly serves the manufacturing of traditional glass spherical photomultiplier tubes.

[0004] However, while this technological approach has achieved partial success, it has also formed inherent technological paradigms and limitations due to the characteristics of glass devices: its structure is designed specifically for handling spherical glass shells, ultimately relying on glass sealing to achieve airtightness, and its complex internal baffle valves and process steps that require the introduction of reactive gases, while improving integration, introduce new internal contamination and reliability risks.

[0005] At this critical juncture, market demands for photomultiplier tube performance have reached new heights, creating an urgent need for miniaturized metal-packaged photomultiplier tubes in cutting-edge fields such as aerospace, high-energy physics, and military applications. These devices require all-metal packaging, high-strength structures capable of withstanding laser welding, and exceptional reliability to withstand extreme mechanical and thermal environments.

[0006] This leads to a new level of technical dilemma that no existing technology has been able to solve: traditional step-by-step processes have been proven infeasible due to contamination issues; and existing integrated glass spherical shell equipment, from its structural principles and tooling design to its core processes, is fundamentally incompatible with the manufacturing requirements of metal encapsulation tubes. Its rotary station mode cannot meet the precision alignment and clamping requirements of metal planar components, its glass sealing process differs significantly from laser welding technology, and the potential risk of internal contamination further threatens the extreme cleanliness required for metal tubes.

[0007] Therefore, there is an urgent need for a new integrated manufacturing solution that serves the characteristics of metal packaging from design concept to execution details. Summary of the Invention

[0008] To address the technical problems existing in the manufacturing of photomultiplier tubes in the prior art, this invention improves the photomultiplier tube manufacturing process by achieving precise alignment of laser welding and local atmosphere control required for alkali source activation through the dynamic combination of shielding cover and loading components.

[0009] The first aspect of this invention proposes a technical solution: a vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing, comprising: A vacuum chamber, wherein the vacuum chamber is equipped with a temperature control system for controlling the temperature of the inner cavity of the vacuum chamber and an atmosphere system for controlling the atmosphere environment inside the chamber; The first tooling component includes a first drive structure, a rotary table, a first shield connected to the first drive structure, and a first loading component connected to the rotary table and used for loading the die assembly. The second tooling component includes a second drive structure and a second loading component connected to the second drive structure and used for loading the light window assembly; An alkali source activation component includes a third drive structure and a telescopic rod connected to the third drive structure, the end of which is connected to a ceramic seat carrying an alkali source and a power supply system for activating the alkali source. The laser welding component is located outside the vacuum chamber and can be laser-welded into a predetermined position inside the vacuum chamber through the light window of the vacuum chamber; The telescopic rod is also provided with a second shielding cover located around the alkali source. The first shielding cover, the first loading component, the second loading component, the second shielding cover, and the alkali source are all disposed inside the cavity of the vacuum chamber. The first loading component can rotate freely relative to the rotary table in a first direction, and the height position of the first loading component is set to correspond to the height position of the optical window, so that after the optical window assembly covers the die assembly, the laser beam of the laser welding component is aligned with the weld between the optical window assembly and the die assembly. The first shield is driven by the first driving structure to move linearly along the first direction and can move back and forth between the first position, the second position and the third position; The second loading component is driven by the second driving structure to move linearly along the first direction and can rotate around the first direction at a predetermined speed, so that the second loading component moves to the fourth position, the fifth position and the sixth position; The alkali source and the second shield are driven by the third driving structure to move linearly in the second direction perpendicular to the first direction, and can move back and forth between the seventh position and the eighth position. Wherein, the axis of the rotating stage, the moving path of the first shielding cover, and the moving path of the second loading component are collinear. When the second shielding cover is in the eighth position, the first shielding cover is in the third position, and the second loading component is in the fifth position, the second loading component, the second shielding cover, and the first shielding cover constitute an alkali source activation chamber. The alkali source activation chamber is a space enclosed by the second loading component, the second shielding cover, and the first shielding cover. The alkali source activation chamber and the cavity body have a gap that communicates with each other, so that after the alkali source is triggered by the power system to evaporate at a predetermined evaporation rate in the alkali source activation chamber, the alkali vapor concentration in the alkali source activation chamber can be maintained within a predetermined range under a predetermined vacuum degree in the cavity body. This allows the photocathode of the light window assembly and the dynode of the die assembly in the alkali source activation chamber to simultaneously form a semiconductor compound thin film. When the second shield is in the seventh position, the first shield is in the first position, and the second loading component is in the sixth position, the optical window assembly and the die assembly are attached together, and the laser beam of the laser welding component is aligned with the weld seam between the optical window assembly and the die assembly and welds the optical window assembly and the die assembly together.

[0010] Preferably, the second shield is constructed as a cylindrical structure with an upper opening and a lower opening. The second loading component is provided with a cover plate. When the second shield is in the eighth position and the second loading component is in the fifth position, the cover plate covers the upper opening of the second shield. The first shield is constructed as a cylindrical structure with an upper opening. When the second shield is in the eighth position and the first shield is in the third position, the upper opening of the first shield can align with the lower opening of the second shield.

[0011] Preferably, the gap in the alkali source activation chamber is formed between the cover plate and the second shield and / or between the first shield and the second shield and / or between the first shield and the first loading component.

[0012] Preferably, the inner side of the first shielding cover is provided with a centering fixture. When the first shielding cover moves from the first position to the second position, the centering fixture is used to adjust the die assembly on the surface of the first loading component to the target position. After the target position is reached, the second loading component moves the loading window assembly to the sixth position, and the window assembly can be fully engaged with the die assembly. The second loading component is driven by the second driving structure and rotates freely around the axis of the rotary table so that the laser welding component completes the sealing of the shell for one revolution.

[0013] Preferably, when the first shield is in the first position, the uppermost position of the first shield is lower than the position of the light window; when the second loading component is in the sixth position, the position of the cover plate is higher than the position of the light window; and when the second shield moves back and forth between the seventh and eighth positions along the second direction, the axis of the second shield is always parallel to the first direction.

[0014] Preferably, the alkali source activation component further includes an electrode mounting plate, the surface of the second shield is provided with a first electrode connected to the alkali source, the electrode mounting plate is connected to a second electrode, the electrode mounting plate is installed on the side wall of the vacuum chamber, the power system is connected to the second electrode, and the first electrode and the second electrode are electrically connected by a flexible cable.

[0015] Preferably, the system further includes an alkali source activation monitoring system, which includes a reflectivity monitoring component and a photocurrent monitoring component. The second driving structure is connected to a hollow rod and drives the hollow rod to extend into the vacuum chamber. The second loading component is connected to the end of the hollow rod. The hollow rod has a magnetohydrodynamic sealing structure at one end outside the vacuum chamber. The reflectivity monitoring component includes a quartz glass rod and a reflectivity monitoring element connected to the quartz glass rod. The quartz glass rod passes through the magnetohydrodynamic sealing structure and the hollow rod and extends to the surface of the optical window assembly, forming an optical path for introducing reflectivity monitoring. The reflectivity monitoring element monitors the cathode reflectivity of the optical window assembly through the quartz glass rod.

[0016] Preferably, the second loading component is configured to include a light-transmitting structure, and a visible light source is provided in the vacuum chamber. When the second loading component is in the fifth position, the visible light source can illuminate the light window assembly through the light-transmitting structure. At this time, the photocurrent monitoring component is used to monitor the photocurrent from the cathode of the light window assembly to the dynode of the die assembly in order to determine the activation quality of the alkaline source.

[0017] Preferably, the atmosphere system includes a vacuum pumping component for maintaining the vacuum level within the vacuum chamber; or the atmosphere system includes a vacuum pumping component and a process gas supply component, wherein the vacuum pumping component is used to maintain the vacuum level within the vacuum chamber, and the process gas supply component is used to supply the required process gas to the vacuum chamber.

[0018] The second aspect of this invention proposes a technical solution: a vacuum integrated manufacturing method for photomultiplier tubes based on laser sealing, using the aforementioned laser-sealed vacuum integrated manufacturing apparatus for photomultiplier tubes, comprising the following steps: Step S1: Install the light window assembly onto the second loading component, install the die assembly onto the first loading component, install the alkali source onto the ceramic seat, and extend the quartz glass rod to be in close contact with the surface of the light window assembly. Step S2: Evacuate the vacuum chamber and maintain it at the preset vacuum level. Use the temperature control system to bake and degas the light window assembly, the core assembly, and the alkali source. Step S3: After baking, cool down to the preset temperature. The alkali source and the second shielding cover move from the seventh position to the eighth position. The second loading component moves from the fourth position to the fifth position and contacts the upper end of the second shielding cover. The first shielding cover moves from the first position to the second position and the third position in sequence and contacts the lower end of the second shielding cover, so that the positions of the light window assembly and the die assembly are aligned and form an alkali source activation chamber. Step S4: The power system applies a predetermined voltage to the second electrode to evaporate the alkali source and form an alkali vapor of a predetermined concentration in the alkali source activation chamber. The optical window assembly and the die assembly in the alkali source activation chamber are coated simultaneously. During this process, the reflectivity of the cathode of the optical window assembly is monitored in real time through the optical path formed by the reflectivity monitoring element and the visible light source is turned on. The photocurrent from the cathode of the optical window assembly to the dynode of the die assembly is monitored by the photocurrent monitoring component. When the reflectivity and photocurrent meet the preset range, the power system is turned off, and the alkali source activation is completed. Step S5: After the alkali source activation is completed, the first shielding cover moves from the third position to the first position, the alkali source and the second shielding cover move from the eighth position to the seventh position, and the second loading component moves from the fifth position to the sixth position, so that the optical window assembly presses against the core assembly. Step S6: The laser welding component emits a laser and irradiates the joint between the optical window assembly and the die assembly. The second driving structure synchronously drives the second loading component to rotate around the first direction. The laser spot melts the metal shell of the optical window assembly to achieve the sealing of the optical window assembly and the die assembly.

[0019] Compared with the prior art, the advantages of the present invention are as follows: This invention ensures the accuracy of the weld seam alignment of the entire tube by rationally arranging the positions of the alkali source component, the optical window component, and the core component, and independently designing the transfer method and action. Furthermore, from baking and degassing, synchronous activation of the photocathode and dynode to the final laser sealing, all core processes are completed continuously in the same vacuum environment and in a single clamping, effectively realizing the integrated transfer activation of the photomultiplier tube and vacuum laser welding degassing, thereby maximizing the vacuum life, stability, and reliability of the photomultiplier tube. Based on the principle of the same physical and chemical process of thin film growth, this invention exposes the optical window and the die to the same alkali metal vapor flow, the same temperature field, and the same reaction time window at the same time, ensuring a high degree of matching between the two semiconductor compound films in terms of stoichiometry, crystal structure, and photoelectric properties, and avoiding the performance inconsistency problem caused by batch differences in traditional step-by-step processes. This invention constructs an adaptive process closed loop that integrates multi-physics information by real-time monitoring of two parameters: reflectivity and photocurrent. This enables intelligent control of the alkali source activation process. The control system can dynamically fine-tune process parameters according to the real-time status of film growth, transforming the traditional operation process that relies on operator experience into a data-driven manufacturing process, thereby improving product consistency, repeatability, and yield. This invention uses high-energy laser welding to replace traditional indium tin alloy sealing or glass sealing, achieving metallurgical bonding of the metal base material. Its sealing strength, temperature resistance, impact and vibration resistance and airtightness are all improved by orders of magnitude, enabling the manufactured photomultiplier tube to meet the urgent needs of extremely demanding application scenarios such as aerospace, military, and high-energy physics. This invention constructs a relatively closed alkali source activation chamber through the coordinated movement of the first shield, the second shield, and the cover plate. This maintains a high concentration of alkali metal atmosphere in the local area, which is much higher than the background concentration, ensuring the efficient, uniform, and synchronous generation of the photocathode and dynode film. It also avoids the concentration runaway caused by complete sealing and effectively prevents alkali metal from contaminating the vacuum chamber body and the weld area. Attached Figure Description

[0020] The accompanying drawings are not strictly to scale. In the drawings, each identical or nearly identical component shown in the various figures can be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, wherein: Figure 1 This is a schematic diagram of the structure of the photomultiplier tube vacuum integrated manufacturing device based on laser sealing, as shown in this invention. Figure 2 This is a schematic diagram showing the first shielding cover in the second position, the second loading component in the fourth position, and the second shielding cover in the eighth position, as shown in this invention. Figure 3 This is a schematic diagram showing the first shielding cover in the third position, the second loading component in the fifth position, and the second shielding cover in the eighth position, as shown in this invention. Figure 4 This is a schematic diagram showing the first shielding cover in the first position, the second loading component in the sixth position, and the second shielding cover in the seventh position, as shown in this invention. Figure 5 This is a schematic diagram of the structure of the second shielding cover shown in this invention; Figure 6 This is a schematic diagram of the structure of the alkali source activation component shown in this invention. Detailed Implementation

[0021] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0022] {Example 1} Combination Figures 1 to 4 As shown, the first aspect of the present invention proposes a technical solution: a vacuum integrated manufacturing device for photomultiplier tubes based on laser sealing, comprising a vacuum chamber 10, a first tooling component 20, a second tooling component 30, an alkali source activation component 40, and a laser welding component 50.

[0023] Combination Figure 1 As shown, the vacuum chamber 10 is equipped with a temperature control system 11 for controlling the temperature of the cavity 101 inside the vacuum chamber 10 and an atmosphere system for controlling the atmosphere environment inside the cavity 101.

[0024] Optionally, the vacuum chamber 10 is used to accommodate the photomultiplier tube workpiece, the tooling for loading the photomultiplier tube workpiece, and the alkali source activation related structures for coating the photomultiplier tube. The temperature and vacuum level in the vacuum chamber 10 are controlled by the temperature control system 11 and the atmosphere system, so that the photomultiplier tube workpiece can complete high-temperature degassing, alkali source activation, centering and pressing assembly, and laser sealing in situ in the vacuum chamber 10.

[0025] In this way, the entire process from degassing to sealing is completed in the same vacuum environment, eliminating air pollution and secondary adsorption. Combined with the inherent advantages of laser sealing, the vacuum life and long-term reliability of the product are effectively guaranteed.

[0026] Optionally, the vacuum chamber 10 has a front-opening door structure, and the front door is sealed to the vacuum chamber 10 by a fluororubber ring.

[0027] Furthermore, the temperature control system 11 includes armored wire heaters arranged on the inner wall of the vacuum chamber 10, and the temperature is adjusted according to process requirements through the temperature control system.

[0028] In an optional embodiment, the atmosphere system includes a vacuum pumping component 12 for maintaining a vacuum level within the vacuum chamber 10.

[0029] Furthermore, the atmosphere system may also include a vacuum pumping component 12 and a process gas supply component 13. The vacuum pumping component 12 is used to maintain the vacuum level in the vacuum chamber 10, and the process gas supply component 13 is used to supply the required process gas to the vacuum chamber 10.

[0030] Specifically, the vacuum pumping component 12 mainly includes a vacuum pump, vacuum valves, supporting pipelines, and a vacuum measuring device. Through the cooperation of the vacuum pump and vacuum valves, the vacuum chamber 10 can be evacuated to a vacuum environment. This is specifically divided into two parts: a pre-evacuation system and a main evacuation system. The pre-evacuation system evacuates the vacuum chamber to a low vacuum, and then the main evacuation system evacuates the vacuum chamber to a high vacuum.

[0031] Specifically, the process gas supply component 13 includes corresponding process gas pipelines and valves, which can fill the vacuum chamber 10 with the required process gas as needed.

[0032] Combination Figure 2 As shown, the first tooling component 20 includes a first drive structure 21, a rotary table 22, a first shield 24 connected to the first drive structure 21, and a first loading component 25 connected to the rotary table 22 for loading the die assembly 200.

[0033] The first tooling component 20 is disposed below the vacuum chamber 10, the drive source of the first drive structure 21 is disposed outside the vacuum chamber 10, the telescopic rod extends into the interior of the vacuum chamber 10, and a guide structure is provided around the telescopic rod to ensure the reliability of the first shield 24 moving along the first direction driven by the telescopic rod.

[0034] Furthermore, the rotary table 22 includes a bearing structure, which allows the first loading component 25 to passively follow the rotation under the action of external force, so as to meet the laser welding requirements during the sealing of the photomultiplier tube. At the same time, the height position of the first loading component 25 is set to correspond to the height position of the light window 14 to facilitate subsequent welding.

[0035] Combination Figure 2 As shown, the second tooling component 30 includes a second drive structure 33 and a second loading component 34 connected to the second drive structure and used for loading the light window assembly 100.

[0036] The second tooling component 30 is positioned above the vacuum chamber 10, and the second drive structure 33 is positioned outside the vacuum chamber 10. Through a support structure 31, the hollow rod 32 at the output end of the second drive structure 33 extends into the vacuum chamber 10 along the first direction and drives the hollow rod 32 to extend and retract along the first direction, so that the second loading component 34 can rise and fall along the first direction.

[0037] Combination Figures 2 to 6 As shown, the alkali source activation component 40 includes a third drive structure 41 and a telescopic rod 431 connected to the third drive structure. The end of the telescopic rod 431 is connected to a ceramic seat carrying the alkali source 46 and a power supply system for activating the alkali source 46.

[0038] Furthermore, the telescopic rod 431 is also provided with a second shield 44 located on the periphery of the alkali source 46. The first shield 24, the first loading component 25, the second loading component 34, the second shield 44, and the alkali source 46 are all located inside the cavity 101 of the vacuum chamber 10.

[0039] Optional, combined Figure 5 and Figure 6As shown, the alkali source activation component 40 also includes an electrode mounting plate 45. The surface of the second shield 44 is provided with a first electrode connected to the alkali source 46. The electrode mounting plate 45 is connected to the second electrode 451. The electrode mounting plate 45 is installed on the side wall of the vacuum chamber 10. The power supply system is connected to the second electrode 451. The first electrode and the second electrode 451 are electrically connected by a flexible cable.

[0040] The third drive structure 41 drives the telescopic rod 431 to extend and retract. The telescopic rod 431 is fitted with a corrugated sleeve 43 on its outside. At the same time, a guide structure 42 is provided on one side of the telescopic rod 431 to ensure the reliability of linear movement.

[0041] Thus, when the second shield 44 moves, the adaptive bending of the flexible cable ensures that the power supply circuit of the power system to the first electrode is normal. By applying different currents through the power system, the alkali source 46 can achieve different evaporation rates.

[0042] Among them, the alkali source 46 is used to activate the photocathode of the multiplier tube and the film layer on the surface of the multiplier electrode.

[0043] Optionally, the alkali source 46 (such as Sb, K, Na) will evaporate into metal vapor when heated. This metal vapor will react chemically with the antimony film on the surface of the photocathode and the dynode to generate intermetallic compounds such as Sb-K and Sb-Na, accompanied by a decrease in reflectivity. The final Sb-K-Na ternary compound is the photocathode with high quantum efficiency.

[0044] As mentioned above, metal vapor is generated when the alkali source 46 evaporates. If the space where the alkali source 46 is located is not restricted, the alkali metal vapor will diffuse into the vacuum chamber 10, resulting in a very low concentration of alkali source vapor and low activation efficiency. Therefore, by setting the second shield 44, it can be combined with other structures to form a relatively independent chamber specifically used in the alkali source activation stage, so as to improve the alkali source activation efficiency.

[0045] Combination Figures 2 to 4 As shown, the laser welding component 50 is located outside the vacuum chamber 10 and can be projected into a predetermined position in the vacuum chamber 10 through the light window 14. Thus, after the photomultiplier tube has undergone the alkaline source activation process, the first tooling component 20 and the third tooling component 30 can be used to cover the light window assembly 100 onto the die assembly 200 and press it tightly. The laser beam of the laser welding component 50 is aimed at the weld seam between the light window assembly 100 and the die assembly 200 to complete the vacuum seal.

[0046] Combination Figure 2 and Figure 4As shown, the first shield 24 is driven by the first drive structure 21 to move linearly along the first direction and can move back and forth between the first position, the second position, and the third position (distributed sequentially from bottom to top); the second loading component 34 is driven by the second drive structure 33 to move linearly along the first direction and can rotate around the first direction at a predetermined speed, so that the second loading component 34 moves to the fourth position, the fifth position, and the sixth position (distributed sequentially from top to bottom); the alkali source 46 and the second shield 44 are jointly driven by the third drive structure 41 to move linearly along the second direction perpendicular to the first direction and can move back and forth between the seventh position and the eighth position (the seventh position is closer to the vacuum chamber 10, and the eighth position is further away).

[0047] As mentioned above, all of the above components can achieve multi-position switching and ensure the repeatability of the moving position, so that the entire process from degassing to sealing can be completed in the same vacuum environment.

[0048] The axis of the rotating platform 22, the moving path of the first shield 24, and the moving path of the second loading component 34 are collinear.

[0049] That is, the first shielding cover 24 moves along a path that coincides with the axis of the rotating stage 22, and the second loading component 34 moves along a path that coincides with the axis of the rotating stage 22, which can ensure that the light window assembly 100 and the die assembly 200 always remain in a centered state.

[0050] Combination Figure 2 As shown, after the high-temperature degassing process, the alkali source activation process will be carried out. At this time, it is necessary to ensure that the core assembly 200 is aligned. The second shield 44 moves from the seventh position to the eighth position. The inner side of the first shield 24 is provided with an alignment fixture 23. When the first shield 24 moves from the first position ( Figure 4 (As shown) Move to the second position ( Figure 2 As shown, the centering fixture 23 adjusts the core assembly 200 on the surface of the first loading component 25 to the target position.

[0051] Thus, once the die assembly 200 is in the target position, in the subsequent process, the second loading component 34 loads the light window assembly 100 and moves it to the sixth position. Figure 4 After (as shown), the light window assembly 100 can fully engage with the die assembly 200, at which point the second loading component 34 is in the fourth position (as shown). Figure 2 (As shown).

[0052] Among them, the tooling 23 not only achieves coarse positioning of the core assembly 200 before alkali source activation, but also establishes an irreversible precision benchmark for the subsequent laser sealing process.

[0053] When the first shield 24 rises from the first position to the second position, the centering fixture 23 contacts the die assembly 200 and applies a precise radial force to adjust the die assembly 200 on the surface of the first loading component 25 to the target position that is completely aligned with the axis of the rotary table 22. This centering action locks the position of the die assembly 200 on the reference axis.

[0054] In the subsequent laser sealing preparation stage, when the second loading component 34 carrying the optical window assembly 100 descends to the sixth position, since the second loading component 34, the first shielding cover 24, and the rotating stage 22 are on the same moving path, and the centering fixture 23 has pre-established the precise position of the die assembly 200, the optical window assembly 100 can achieve automatic alignment with the die assembly 200 without deviation, avoiding the tedious operation and accumulated error that require repeated centering adjustments in the traditional process.

[0055] As mentioned above, the reference axis established by the tooling 23 is completely coincident with the axis of rotation of the whole system during subsequent laser sealing. Thus, when the second drive structure 33 drives the second loading component 34, the optical window assembly 100 and the core assembly 200 pressed against it to rotate around the axis of the rotary table 22, the relative position of any point on the weld seam with respect to the laser focus remains constant during the rotation, ensuring the uniformity of the penetration depth and the consistency of the airtightness of the circumferential weld seam.

[0056] Combination Figure 3 As shown, after the preparation process is completed, the alkali source activation chamber 102 needs to be constructed. Specifically, when the second shield 44 is in the eighth position (e.g. Figure 3 As shown), the first shielding cover 24 is in the third position (as shown). Figure 3 As shown), when the second loading component 34 is in the fifth position (as shown), Figure 3 As shown, the alkaline source activation chamber 102 is composed of the second loading component 34, the second shielding cover 44 and the first shielding cover 24.

[0057] Specifically, the alkali source activation chamber 102 is a relatively sealed space formed by the cylindrical second loading component 34, the cylindrical second shield 44, and the cylindrical first shield 24 facing each other, in which the alkali source can be activated.

[0058] In an optional embodiment, combined with Figure 5 and Figure 6 As shown, the second shield 44 is constructed as a cylindrical structure with an upper opening and a lower opening.

[0059] Furthermore, the second loading component 34 is provided with a cover plate 341, and the first shield 24 is constructed as a cylindrical structure with an upper opening.

[0060] like Figure 3As shown, when the second shielding cover 44 is in the eighth position and the second loading component 34 is in the fifth position, the cover plate 341 covers the upper opening of the second shielding cover 44. When the second shielding cover 44 is in the eighth position and the first shielding cover 24 is in the third position, the upper opening of the first shielding cover 24 can be connected with the lower opening of the second shielding cover 44.

[0061] Furthermore, there is a gap between the alkali source activation chamber 102 and the cavity 101 that allows the alkali source 46 to be activated by the power system and evaporate at a predetermined evaporation rate in the alkali source activation chamber 102. This ensures that the alkali vapor concentration in the alkali source activation chamber 102 is maintained within a predetermined range under a predetermined vacuum degree in the cavity 101. This allows the photocathode of the light window assembly 100 and the dynode surface of the die assembly 200 in the alkali source activation chamber 102 to simultaneously form a semiconductor compound thin film.

[0062] Specifically, the alkali source activation chamber 102 is not a sealed reaction container, but a dynamic microenvironment control device with precisely controlled diffusion channels. Through the preset gap between the cover plate 341 of the second loading component 34 and the upper opening of the second shield 44, the preset gap between the first shield 24 and the lower opening of the second shield 44, and the preset gap between the first shield 24 and the first loading component 25, multiple precisely controlled escape channels are formed for the directional diffusion of alkali vapor molecules from the activation chamber to the main chamber 101.

[0063] Therefore, when the alkali source 46 is heated and evaporated, alkali metal atoms form a high-concentration region within the activation chamber 102. Due to the concentration gradient, a small number of atoms diffuse outward through the aforementioned preset gaps. Simultaneously, the main pumping system of the vacuum chamber 10 continues to operate, promptly removing the diffused alkali atoms. This process establishes a dynamic equilibrium within the activation chamber 102, stabilizing the evaporation rate and outward diffusion rate of the alkali source. The concentration of alkali metal vapor within the activation chamber 102 can be precisely controlled within a predetermined range that ensures efficient film formation without causing the film layer to become porous due to oversaturation.

[0064] Specifically, through the confinement effect of the alkaline source activating chamber 102 on the alkali source evaporating gas, most of the flight paths of the atoms evaporated from the alkali source are restricted within this cylindrical space. They can only continuously collide and reflect within the cylinder, eventually depositing on the light window and the surface of the core assembly located inside the cylinder. This allows the alkaline source activating chamber 102 to continuously maintain a stable high alkali metal concentration environment that is much higher than the background of the external vacuum chamber.

[0065] Furthermore, if the alkali source activation chamber 102 is completely airtight, the alkali metal concentration will rise uncontrollably, resulting in an excessively thick and porous film, which in turn reduces performance. Simultaneously, excessive pressure may also adversely affect precision components. Therefore, the alkali source activation chamber 102 has a gap communicating with the chamber 101, allowing a small amount of alkali metal to diffuse outwards and form a dynamic balance with the continuous internal evaporation replenishment.

[0066] In this way, the system can precisely control the growth of the film by precisely controlling the heating current (evaporation rate) and time of the alkali source. The vacuum system is responsible for removing the small amount of alkali metal that diffuses out, preventing it from accumulating in the chamber. That is, a local reaction microenvironment with a stable concentration gradient is formed in the main vacuum chamber, realizing precise control of the alkali metal vapor concentration and solving the problems of low alkali source utilization and concentration runaway in the existing technology.

[0067] In an optional embodiment, the gap in the alkali source activation chamber 102 is formed between the cover plate 341 and the second shield 44 and / or between the first shield 24 and the second shield 44 and / or between the first shield 24 and the first loading component 25.

[0068] Preferably, the gap is formed between the first shield 24 and the first loading component 25. In this way, the height of the first loading component 25 is kept at a fixed position, which is beneficial to maintain the size of the gap by controlling the position of the first shield 24. Furthermore, since the gap is close to the vacuum chamber 10, the alkaline vapor that overflows from the gap can be removed by the vacuum system through a shorter path.

[0069] It should be understood that the formation of semiconductor compound thin films (such as Sb-K-Na multi-alkali films) on the surfaces of the photocathode and dynode depends on the solid-state reaction and interdiffusion of alkali metal atoms with the substrate metal (such as antimony) at specific temperatures. This reaction process is extremely sensitive to parameters such as the concentration of alkali metal vapor, temperature, reaction time, and background vacuum. If the optical window assembly and the die assembly are activated at different times and in different spaces, even if the nominal process parameters are the same, it is difficult to avoid inconsistencies in film performance due to batch differences, environmental fluctuations, and other factors.

[0070] In this application, alkali metal atoms evaporated from the same alkali source are uniformly distributed within chamber 102, ensuring that the atomic ratio of the alkali metal deposited on the optical window and dynode surface is exactly the same as that of the substrate antimony film, thereby guaranteeing that the formed semiconductor compounds have the same stoichiometry. The identical temperature field ensures that the surface migration energy and nucleation conditions of the two films are consistent during growth, resulting in essentially identical grain size and crystal orientation distribution. The quantum efficiency of the photocathode and the secondary electron emission coefficient of the first dynode are matched in material composition and structure, ensuring efficient electron transmission and signal linearity during the dynode amplification process.

[0071] As described above, the alkali source activation process, conducted simultaneously under the same atmosphere and temperature, uses the same alkali metal vapor flow to deposit semiconductor thin films on the optical window and all dynodes. These films exhibit highly consistent stoichiometry, crystal structure, and performance characteristics, ensuring the uniformity and linearity of the electron signal during the multiplication process. Furthermore, the film preparation of the two most critical components is completed in a single setup, vacuuming, baking, and activation process, greatly simplifying the workflow and avoiding contamination and risks associated with multiple processing steps.

[0072] Combination Figure 4 As shown, after the alkali source activation process is completed, the second shield 44 is reset from the eighth position to the seventh position, the first shield 24 is reset to the first position, and the second loading component 34 is lowered from the fifth position to the sixth position, so that the light window assembly 100 and the die assembly 200 are attached together.

[0073] When the second shield 44 moves back and forth between the seventh and eighth positions along the second direction, the axis of the second shield 44 is always parallel to the first direction to ensure the repeatability and consistency of the position of the second shield 44 during repeated movements.

[0074] Furthermore, the laser beam of the laser welding component 50 passes through the optical window 14 and is aligned with the weld seam between the optical window assembly 100 and the die assembly 200, thus welding the optical window assembly 100 and the die assembly 200 together.

[0075] During the welding process, the uppermost position of the first shield 24 is lower than the position of the optical window 14 to avoid blocking the laser beam. When the second loading component 34 is in the sixth position, the position of the cover plate 341 is higher than the position of the optical window 14 to avoid blocking the laser beam.

[0076] Specifically, during welding, the second loading component 34 is driven by the second driving structure 33 to rotate freely around the axis of the rotary table 22, so that the laser welding component 50 completes one revolution of the tube shell.

[0077] When the tube shell is circular, it can be rotated at a constant speed in conjunction with the laser power. When the tube shell is square, it can be laser-sealed on each side sequentially in conjunction with the laser.

[0078] In an optional embodiment, the laser welding component 50 includes a laser disposed outside the vacuum chamber 10. The laser is introduced into the vacuum chamber through a laser anti-transmission window 14 on the side wall of the vacuum chamber 10 and aligned with the weld seam. A precision displacement device matching the external laser is used to achieve vacuum laser hermetic sealing of the photomultiplier tube in conjunction with the rotation of the photomultiplier tube. In the above embodiment, an alkali source activation monitoring system is also included. The alkali source activation monitoring system includes a reflectivity monitoring component and a photocurrent monitoring component, used to monitor reflectivity and photocurrent during the alkali source activation process.

[0079] Combination Figures 2 to 4 As shown, the second driving structure 33 connects to the hollow rod 32 and drives the hollow rod 32 to extend into the vacuum chamber 10. The second loading component 34 is connected to the end of the hollow rod 32. The hollow rod 32 is provided with a magnetohydrodynamic sealing structure at one end outside the vacuum chamber 10. The reflectivity monitoring component includes a quartz glass rod 62 and a reflectivity monitoring element connected to the quartz glass rod 62. The quartz glass rod 62 passes through the magnetohydrodynamic sealing structure and the hollow rod 32 and extends to the surface of the optical window assembly 100, forming an optical path for introducing reflectivity monitoring. The reflectivity monitoring element monitors the cathode reflectivity of the optical window assembly 100 through the quartz glass rod 62.

[0080] It should be understood that during the alkali source activation process, photocurrent and reflectivity can reflect the growth quality of the thin film from different dimensions.

[0081] If the reflectivity decreases too quickly or too low, it may mean that the alkali metal evaporation rate is too fast, resulting in an excessively thick film or a loose structure. Therefore, it is necessary to slightly reduce the alkali source heating current to reduce the evaporation rate and allow the film to grow more densely and slowly. If the reflectivity decreases too slowly or too high, it may mean that the alkali metal evaporation rate is too slow, resulting in the film not yet reaching the optimal thickness. It is necessary to slightly increase the alkali source heating current to increase the evaporation rate and allow the film to reach the target thickness more quickly.

[0082] In an optional embodiment, the control system performs dynamic, small-amplitude PID (proportional-integral-derivative) adjustments based on the deviation of the real-time reflectivity curve, bringing it back to the preset process track.

[0083] Furthermore, the second loading component 34 is configured to include a light-transmitting structure, and a visible light source 61 is provided in the vacuum chamber 10. When the second loading component 34 is in the fifth position, the visible light source 61 (such as a halogen lamp) can shine through the light-transmitting structure onto the light window assembly 100. At this time, the photocurrent monitoring component is used to monitor the photocurrent from the cathode of the light window assembly 100 to the die assembly 200 times the dynode to determine the activation quality of the alkaline source.

[0084] It should be understood that when the photocurrent is not up to standard, it means that the reaction temperature is not suitable, resulting in a poor crystal structure of the semiconductor compound. Continuous evaporation can be changed to intermittent evaporation to give surface atoms more time to migrate and form an ordered lattice.

[0085] As mentioned above, during the alkali source activation process, the process status can be monitored based on the real-time response of the material (reflectivity curve and photocurrent growth) and precise fine-tuning can be made.

[0086] As mentioned above, the alkali source activation monitoring system constructs an adaptive process closed-loop control system based on the fusion of multi-physics field information by fusing the dual parameters of reflectivity and photocurrent. Reflectivity monitoring reflects the physical scale information of thin film growth (film thickness and surface morphology), while photocurrent monitoring directly characterizes the functional scale information of the thin film (photoelectric conversion efficiency).

[0087] Because reflectivity and photocurrent exhibit specific correlation and evolution patterns during the alkali source activation process: in the early stage of activation, alkali metals begin to deposit and react with the antimony film, reflectivity decreases rapidly, while photocurrent slowly increases from zero; in the middle stage of activation, the rate of reflectivity decrease slows down, and photocurrent enters a rapid growth stage, with the two showing a mirror relationship; in the later stage of activation, reflectivity tends to stabilize, and photocurrent may slightly decline after reaching its peak, marking the appearance of the optimal activation point.

[0088] Based on this correlation, the control system of the present invention automatically adjusts the alkali source heating current to correct the evaporation rate when the reflectance curve deviates from the preset trajectory; when the photocurrent growth lags behind the reflectance change, the system fine-tunes the substrate temperature or adjusts the evaporation strategy (such as switching from continuous evaporation to intermittent evaporation) to optimize the surface chemical reaction kinetics.

[0089] The aforementioned dual closed-loop control strategy of constant reflectivity and constant photocurrent transforms the traditionally highly experience-dependent operation of alkali source activation into a data-driven precision engineering process. Furthermore, the aforementioned monitoring process is achieved in situ and in real-time without disrupting the vacuum or contacting the workpiece surface.

[0090] {Example 2} Combination Figure 2 and Figure 4As shown, the second aspect of the present invention proposes a technical solution: a vacuum integrated manufacturing method for photomultiplier tubes based on laser sealing, using the aforementioned laser-sealed vacuum integrated manufacturing apparatus for photomultiplier tubes, comprising the following steps: Step S1: Install the light window assembly 100 onto the second loading component 34, install the die assembly 200 onto the first loading component 25, install the alkali source 46 onto the ceramic seat, and extend the quartz glass rod to be in close contact with the surface of the light window assembly 100. Step S2: Evacuate the vacuum chamber 10 and maintain it at a preset vacuum level. Use the temperature control system 11 to bake and degas the light window assembly 100, the core assembly 200 and the alkali source 46. Step S3: After baking, the temperature is lowered to the preset temperature. The alkali source 46 and the second shield 44 are moved from the seventh position to the eighth position. The second loading component 34 is moved from the fourth position to the fifth position and contacts the upper end of the second shield 44. The first shield 24 is moved from the first position to the second position and the third position in sequence and contacts the lower end of the second shield 44, so that the positions of the light window assembly 100 and the die assembly 200 are aligned and form the alkali source activation chamber 102. Step S4: The power system applies a predetermined voltage to the second electrode 451, causing the alkali source 46 to evaporate and forming an alkali vapor of a predetermined concentration in the alkali source activation chamber 102. This vapor simultaneously coats the light window assembly 100 and the die assembly 200 in the alkali source activation chamber 102. During this process, the reflectivity of the cathode of the light window assembly 100 is monitored in real time through the reflectivity monitoring optical path formed by the quartz glass rod 62 using a reflectivity monitoring element. The visible light source 61 is turned on, and the photocurrent from the cathode of the light window assembly 100 to the dynode of the die assembly 200 is monitored by the photocurrent monitoring component. When the reflectivity and photocurrent meet the preset range, the power system is turned off, and the alkali source activation is completed. Step S5: After the alkali source activation is completed, the first shield 24 moves from the third position to the first position, the alkali source 46 and the second shield 44 move from the eighth position to the seventh position, and the second loading component 34 moves from the fifth position to the sixth position, so that the light window assembly 100 presses against the core assembly 200. Step S6: The laser welding component 50 emits a laser and irradiates the joint between the light window assembly 100 and the die assembly 200. The second driving structure 33 synchronously drives the second loading component 34 to rotate around the first direction. The laser spot melts the metal shell of the light window assembly 100 to achieve a seal between the light window assembly 100 and the die assembly 200.

[0091] In a specific embodiment, taking the manufacturing of a miniaturized metal-encapsulated photomultiplier tube as an example, the fabrication process is as follows: Step S1: Initial clamping and preparation Open the front door of the vacuum chamber 10, and install and fix the die assembly 200, which has completed internal electrode assembly and indium sealing, onto the first loading component 25; install and fix the optical window assembly 100, which has completed preliminary sealing with the sapphire optical window, onto the second loading component 34; install the alkali source 46 containing antimony (Sb), potassium (K), and sodium (Na) onto the ceramic seat of the alkali source activation component 40; adjust the quartz glass rod 62 that passes through the hollow rod 32 so that its lower end is tightly attached to the inner surface of the optical window of the optical window assembly 100; close and seal the front door of the vacuum chamber 10.

[0092] Step S2: Vacuuming and Degassing The vacuum pumping unit 12 in the atmosphere system is activated, and the cavity 101 of the vacuum chamber 10 is evacuated to a high vacuum state (e.g., better than 5.0 × 10⁻⁻⁻⁶) through the pre-evacuation system and the main evacuation system in sequence. 5 Pa); start the temperature control system 11, heat up the vacuum chamber 10 according to the preset program, and bake the light window assembly 100, the core assembly 200 and the alkali source 46 at high temperature to remove gas (for example, keep at 350°C for 1 hour) so as to completely release the gas adsorbed inside the material.

[0093] Step S3: Constructing the alkali source activation chamber After baking and degassing, the control system automatically cools the cavity 101 to the optimal temperature for photocathode preparation (e.g., 150°C); the third drive structure 41 is activated, driving the alkali source 46 and its second shield 44 to move horizontally along the second direction, from the seventh position (avoidance position) to the eighth position (activation position); the second drive structure 33 is activated, driving the second loading component 34 and its light window assembly 100 to descend along the first direction, moving from the fourth position to the fifth position, so that its cover plate 341 contacts the upper opening of the second shield 44; the first drive structure 21 is activated, driving the first shield 24 to rise along the first direction, passing through the first position and the second position in sequence. At this position, the centering fixture 23 on its inner side precisely positions the core assembly 200, finally reaching the third position, so that its upper opening aligns with the lower opening of the second shield 44.

[0094] At this time, the cover plate 341 of the second loading component 34, the second shield 44 and the first shield 24 together form an alkali source activation chamber 102 that is connected to the main cavity 101 through a gap.

[0095] Step S4: In-situ activation and real-time monitoring The power system applies a precisely controlled current to the second electrode 451, heating and evaporating the alkali source 46. The evaporated alkali metal vapor is confined within the alkali source activation chamber 102, creating a localized high-concentration environment. Simultaneously, this environment deposits and chemically reacts on the photocathode of the light window assembly 100 and the dynode of the die assembly 200, forming an Sb-K-Na semiconductor compound thin film. During this process, a reflectivity monitoring element monitors the reflectivity changes of the film layer on the light window surface in real time through a monitoring optical path introduced by a quartz glass rod 62. Simultaneously, a visible light source 61 is turned on, illuminating the semi-finished cathode, and a photocurrent monitoring component monitors the photocurrent signal from the cathode to the first dynode in real time.

[0096] The control system dynamically fine-tunes the alkali source heating current or substrate temperature based on real-time data curves of reflectivity and photocurrent to ensure the process operates on the optimal trajectory. When both indicators reach and stabilize within the preset range, activation is considered complete, and the power system is shut down.

[0097] Step S5: Centering and tightening After activation, each system is reset in sequence: the first shield 24 descends to the first position, the alkali source 46 and the second shield 44 move horizontally back to the seventh position, and the second loading component 34 carrying the optical window assembly 100 descends to the sixth position. Using the reference established by the previously aligned tooling 23, it achieves precise alignment and clamping with the die assembly 200, preparing for laser sealing.

[0098] Step S6: Laser sealing When the laser welding component 50 is activated, the laser beam is precisely focused through the optical window 14 onto the annular weld between the optical window assembly 100 and the core assembly 200. The second drive structure 33 synchronously drives the second loading component 34, the optical window assembly 100 and the core assembly 200 pressed against it as a whole to rotate around the first direction (rotary table axis). The laser spot melts the metal shell (such as Kovar alloy) at the weld, achieving metallurgical bonding. After one rotation, the airtight vacuum sealing of the entire tube is completed.

[0099] Finally, the device is cooled down, filled with high-purity nitrogen, and the manufactured high-performance metal-encapsulated photomultiplier tube is removed from the chamber.

[0100] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing, characterized in that, include: A vacuum chamber (10) is provided with a temperature control system (11) for controlling the temperature of the cavity (101) inside the vacuum chamber (10) and an atmosphere system for controlling the atmosphere environment inside the cavity (101); The first tooling component (20) includes a first drive structure (21), a rotary table (22), a first shield (24) connected to the first drive structure (21), and a first loading component (25) connected to the rotary table (22) and used for loading the die assembly (200). The second tooling component (30) includes a second drive structure (33) and a second loading component (34) connected to the second drive structure and used for loading the light window assembly (100). The alkali source activation component (40) includes a third drive structure (41) and a telescopic rod (431) connected to the third drive structure. The end of the telescopic rod (431) is connected to a ceramic seat carrying an alkali source (46) and a power system for activating the alkali source (46). The laser welding component (50) is disposed outside the vacuum chamber (10) and can be injected into a predetermined position in the vacuum chamber (10) through the light window (14) of the vacuum chamber (10); The telescopic rod (431) is also provided with a second shield (44) located on the periphery of the alkali source (46). The first shield (24), the first loading component (25), the second loading component (34), the second shield (44) and the alkali source (46) are all located in the cavity (101) of the vacuum chamber (10). The first loading component (25) can rotate freely relative to the rotating table (22) in a first direction, and the height position of the first loading component (25) is set to correspond to the height position of the light window (14), so that after the light window assembly (100) covers the die assembly (200), the laser beam of the laser welding component (50) is aligned with the weld between the light window assembly (100) and the die assembly (200); The first shield (24) is driven by the first driving structure (21) to move linearly in the first direction and can move back and forth between the first position, the second position and the third position; The second loading component (34) is driven by the second driving structure (33) to move linearly along the first direction and can rotate around the first direction at a predetermined speed, so that the second loading component (34) moves to the fourth position, the fifth position and the sixth position; The alkali source (46) and the second shield (44) are driven by the third driving structure (41) to move linearly in the second direction perpendicular to the first direction, and can move back and forth between the seventh position and the eighth position; The axis of the rotating platform (22), the moving path of the first shield (24), and the moving path of the second loading component (34) are collinear. When the second shield (44) is in the eighth position, the first shield (24) is in the third position, and the second loading component (34) is in the fifth position, the second loading component (34), the second shield (44), and the first shield (24) constitute the alkali source activation chamber (102). The alkali source activation chamber (102) is composed of the second loading component (34), the second shield (44), and the first shield. (24) The space enclosed by the alkaline source activation chamber (102) and the cavity (101) have a gap that is interconnected, so that after the alkaline source (46) is triggered by the power system to evaporate at a predetermined evaporation rate in the alkaline source activation chamber (102), it can maintain the concentration of alkaline vapor in the alkaline source activation chamber (102) within a predetermined range under a predetermined vacuum degree in the cavity (101), so that the photocathode of the light window assembly (100) and the dynode surface of the die assembly (200) in the alkaline source activation chamber (102) simultaneously form a semiconductor compound thin film; When the second shield (44) is in the seventh position, the first shield (24) is in the first position, and the second loading component (34) is in the sixth position, the light window assembly (100) and the die assembly (200) are attached together, and the laser beam of the laser welding component (50) is aligned with the weld seam of the light window assembly (100) and the die assembly (200) and welds the light window assembly (100) and the die assembly (200) together.

2. The vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing according to claim 1, characterized in that, The second shield (44) is constructed as a cylindrical structure with an upper opening and a lower opening. The second loading component (34) is provided with a cover plate (341). When the second shield (44) is in the eighth position and the second loading component (34) is in the fifth position, the cover plate (341) covers the upper opening of the second shield (44). The first shield (24) is constructed as a cylindrical structure with an upper opening. When the second shield (44) is in the eighth position and the first shield (24) is in the third position, the upper opening of the first shield (24) can be connected with the lower opening of the second shield (44).

3. The vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing according to claim 2, characterized in that, The gap in the alkaline source activation chamber (102) is formed between the cover plate (341) and the second shield (44) and / or between the first shield (24) and the second shield (44) and / or between the first shield (24) and the first loading component (25).

4. The vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing according to claim 1, characterized in that, The inner side of the first shield (24) is provided with a centering fixture (23). When the first shield (24) moves from the first position to the second position, the centering fixture (23) is used to adjust the die assembly (200) on the surface of the first loading component (25) to the target position. After the target position, the second loading component (34) loads the light window assembly (100) and moves to the sixth position. The light window assembly (100) can be fully engaged with the die assembly (200). The second loading component (34) is driven by the second driving structure (33) and rotates freely around the axis of the rotary table (22) so that the laser welding component (50) completes the sealing of the shell one revolution.

5. The vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing according to claim 2, characterized in that, When the first shield (24) is in the first position, the uppermost position of the first shield (24) is lower than the position of the light window (14). When the second loading component (34) is in the sixth position, the position of the cover plate (341) is higher than the position of the light window (14). When the second shield (44) moves back and forth between the seventh and eighth positions along the second direction, the axis of the second shield (44) is always parallel to the first direction.

6. The vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing according to claim 1, characterized in that, The alkali source activation component (40) also includes an electrode mounting plate (45). The surface of the second shield (44) is provided with a first electrode connected to the alkali source (46). The electrode mounting plate (45) is connected to a second electrode (451). The electrode mounting plate (45) is installed on the side wall of the vacuum chamber (10). The power supply system is connected to the second electrode (451). The first electrode and the second electrode (451) are electrically connected by a flexible cable.

7. The vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing according to any one of claims 1-6, characterized in that, It also includes an alkali source activation monitoring system, which includes a reflectivity monitoring component and a photocurrent monitoring component. The second driving structure (33) is connected to the hollow rod (32) and drives the hollow rod (32) to extend into the vacuum chamber (10). The second loading component (34) is connected to the end of the hollow rod (32). The hollow rod (32) is provided with a magnetic fluid sealing structure at one end outside the vacuum chamber (10). The reflectivity monitoring component includes a quartz glass rod (62) and a reflectivity monitoring element connected to the quartz glass rod (62). The quartz glass rod (62) passes through the magnetic fluid sealing structure and the hollow rod (32) and extends to the surface of the light window assembly (100), forming an optical path for introducing reflectivity monitoring. The reflectivity monitoring element monitors the cathode reflectivity of the light window assembly (100) through the quartz glass rod (62).

8. The vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing according to claim 7, characterized in that, The second loading component (34) is configured to include a light-transmitting structure. A visible light source (61) is provided in the vacuum chamber (10). When the second loading component (34) is in the fifth position, the visible light source (61) can irradiate the light window assembly (100) through the light-transmitting structure. At this time, the photocurrent monitoring component is used to monitor the photocurrent from the cathode of the light window assembly (100) to the dynode of the die assembly (200) to determine the activation quality of the alkaline source.

9. The vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing according to any one of claims 1-6, characterized in that, The atmosphere system includes a vacuum pumping component (12) for maintaining the vacuum level in the vacuum chamber (10); or the atmosphere system includes a vacuum pumping component (12) and a process gas supply component (13), wherein the vacuum pumping component (12) is used to maintain the vacuum level in the vacuum chamber (10), and the process gas supply component (13) is used to supply the required process gas to the vacuum chamber (10).

10. A vacuum integrated manufacturing method for photomultiplier tubes based on laser sealing, characterized in that, The vacuum integrated manufacturing apparatus for photomultiplier tubes based on laser sealing according to any one of claims 1-9 includes the following steps: Step S1: Install the light window assembly (100) onto the second loading component (34), install the die assembly (200) onto the first loading component (25), install the alkali source (46) onto the ceramic seat, and extend the quartz glass rod to be in close contact with the surface of the light window assembly (100); Step S2: Evacuate the vacuum chamber (10) and maintain it at the preset vacuum level. Use the temperature control system (11) to bake and degas the light window assembly (100), the core assembly (200) and the alkali source (46). Step S3: After baking, the temperature is lowered to the preset temperature. The alkali source (46) and the second shield (44) are moved from the seventh position to the eighth position. The second loading component (34) is moved from the fourth position to the fifth position and contacts the upper end of the second shield (44). The first shield (24) is moved from the first position to the second position and the third position in sequence and contacts the lower end of the second shield (44), so that the positions of the light window assembly (100) and the die assembly (200) are aligned and form the alkali source activation chamber (102). Step S4: The power system applies a predetermined voltage to the second electrode (451) to evaporate the alkali source (46) and form an alkali vapor of a predetermined concentration in the alkali source activation chamber (102). The light window assembly (100) and the die assembly (200) in the alkali source activation chamber (102) are coated simultaneously. During this process, the reflectivity of the cathode of the light window assembly (100) is monitored in real time through the reflectivity monitoring optical path formed by the reflectivity monitoring element and the quartz glass rod (62). The visible light source (61) is turned on, and the photocurrent from the cathode of the light window assembly (100) to the dynode of the die assembly (200) is monitored by the photocurrent monitoring component. When the reflectivity and photocurrent meet the preset range, the power system is turned off, and the alkali source activation is completed. Step S5: After the alkaline source activation is completed, the first shield (24) moves from the third position to the first position, the alkaline source (46) and the second shield (44) move from the eighth position to the seventh position, and the second loading component (34) moves from the fifth position to the sixth position, so that the light window assembly (100) presses against the core assembly (200). Step S6: The laser welding component (50) emits a laser and irradiates the joint between the light window assembly (100) and the die assembly (200). The second driving structure (33) synchronously drives the second loading component (34) to rotate around the first direction. The laser spot melts the metal shell of the light window assembly (100) to achieve the sealing of the light window assembly (100) and the die assembly (200).

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