A film coating tool for a photomultiplier tube part

Abstract

The utility model relates to a kind of photomultiplier tube parts coating tool, belong to photomultiplier tube preparation technical field, multiple first limiting grooves for limiting first dynode are provided on the circular substrate, multiple second limiting grooves for limiting final stage dynode, multiple first limiting parts for limiting second dynode and multiple second limiting parts for limiting cathode are provided on the circular substrate. The present application is accurate in positioning and has significant anti-pollution effect. The first limiting groove and the second limiting groove are accurately fitted with the first dynode and the final stage dynode respectively. The first limiting part and the second limiting part fix the planar part through the baffle or the limiting column. The flexible sealing strip is used to block the gap, and the device performance is guaranteed.

Description

Technical Field

[0001] This utility model belongs to the field of photomultiplier tube manufacturing technology, and particularly relates to a coating tooling for photomultiplier tube parts. Background Technology

[0002] A photomultiplier tube (PMT) is a vacuum electronic device that converts weak light signals into electrical signals and amplifies them. It is a key component determining the performance of optical measuring instruments and spectroscopic analysis instruments, and is widely used in many sectors of the national economy. The core performance advantage of a PMT lies in its extremely high gain (typically reaching 10⁻⁶). 6 These characteristics enable it to detect extremely weak light signals, even at the single-photon level. Furthermore, photomultiplier tubes (PMTs) have a fast response speed and a wide dynamic range, making them suitable for broadband detection from the ultraviolet to the near-infrared band. This property makes them an indispensable key component in fields such as spectral analysis, particle physics experiments, and nuclear detection.

[0003] To ensure a stable, high-vacuum operating environment can be established and maintained inside a photomultiplier tube, a coating layer must be pre-deposited on the surfaces of its internal components before encapsulation. This coating layer is crucial for achieving efficient photoelectric conversion and stable secondary electron emission. During this coating process, the various electrode components inside the photomultiplier tube need to be precisely fixed, ensuring that only specific surfaces are exposed to the coating material. However, existing coating fixtures lack an effective back-side protection structure, resulting in contamination of the non-working surfaces of the components by the coating material.

[0004] These problems seriously affect the performance stability and production efficiency of photomultiplier tubes. Therefore, there is an urgent need to develop a special coating fixture that can provide effective fixation and comprehensive back protection for parts of different shapes. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is: a coating fixture for a photomultiplier tube component, comprising: a circular substrate, wherein the circular substrate is provided with a plurality of first limiting grooves for limiting the first dynode, a plurality of second limiting grooves for limiting the final dynode, a plurality of first limiting portions for limiting the second dynode, and a plurality of second limiting portions for limiting the cathode.

[0006] Furthermore, a plurality of first limiting grooves, a plurality of second limiting grooves, a plurality of first limiting portions and a plurality of second limiting portions are arranged in a circumferential array on the circular substrate.

[0007] Furthermore, the first limiting part and the second limiting part have the same structure.

[0008] Furthermore, the circular substrate is provided with a second limiting part, a second limiting groove, a first limiting part, and a first limiting groove arranged sequentially from the center outwards.

[0009] Furthermore, the first limiting part includes two first baffles disposed on the circular substrate, the first baffles being positioned between the two side rods of the second multiplier end part or between the two side rods of the cathode end part.

[0010] Furthermore, the arc-shaped end of the first multiplier electrode is fitted with the inner wall of the first limiting groove, and the arc-shaped end of the final multiplier electrode is fitted with the inner wall of the second limiting groove.

[0011] Furthermore, a circular through hole is provided at the center of the circular substrate.

[0012] Furthermore, the first limiting groove and the second limiting groove are respectively detachably mounted on the circular substrate via a base.

[0013] Furthermore, the first limiting part and the second limiting part are detachably mounted on the circular substrate.

[0014] Furthermore, the first limiting part includes four limiting posts for limiting the four side rods at both ends of the second multiplier electrode or the four side rods at the cathode end, and a flexible sealing strip for sealing the end of the second multiplier electrode or the cathode end is provided on the circular substrate.

[0015] The beneficial effects of this utility model are: This application features precise positioning and significant anti-contamination effect. The first and second limiting grooves are precisely fitted to the first and final multiplier electrodes, respectively. The first and second limiting parts fix the planar parts with baffles or limiting posts, and cooperate with flexible sealing strips to seal gaps and ensure device performance.

[0016] This application is highly versatile and efficient in production. Each limiting component is detachable and replaceable, making it compatible with different types of parts. The circumferential array layout of the circular substrate can simultaneously load multiple sets of parts. It is well-suited for magnetron sputtering equipment, rotates stably, significantly improves batch coating efficiency, and reduces production costs. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the base position of this utility model; Figure 3 This is a schematic diagram of the position of the limiting post of this utility model; Figure 4 This is a schematic diagram showing the position of the first baffle of this utility model; Figure 5 This is a schematic diagram of the first multiplier structure of this utility model; Figure 6 This is a schematic diagram of the second multiplier structure of this utility model; Figure 7 This is a schematic diagram of the final stage multiplier structure of this utility model; Figure 8 This is a schematic diagram of the cathode structure of this utility model.

[0018] Reference numerals in the attached drawings: 1. Circular substrate; 2. First limiting groove; 3. Second limiting groove; 4. First limiting part; 5. Second limiting part; 6. Circular through hole; 7. Substrate; 41. First baffle; 42. Limiting post; 43. Flexible sealing strip; 100. First multiplier electrode; 200. Second multiplier electrode; 300. Final multiplier electrode; 400. Detailed Implementation

[0019] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0020] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] The present invention will be further described below with reference to embodiments and accompanying drawings: A coating fixture for a photomultiplier tube component includes: a circular substrate 1, on which a plurality of first limiting grooves 2 for limiting a first dynode 100, a plurality of second limiting grooves 3 for limiting a final dynode 300, a plurality of first limiting portions 4 for limiting a second dynode 200, and a plurality of second limiting portions 5 for limiting a cathode 400 are provided. The plurality of first limiting grooves 2, the plurality of second limiting grooves 3, the plurality of first limiting portions 4, and the plurality of second limiting portions 5 are arranged in a circumferential array on the circular substrate 1. The first limiting portions 4 and the second limiting portions 5 have the same structure. The circular substrate 1 is arranged sequentially from the center outwards with the second limiting portions 5, the second limiting grooves 3, the first limiting portions 4, and the first limiting grooves 2. The first limiting part 4 includes two first baffles 41 disposed on the circular substrate 1. The first baffles 41 are positioned between the two side rods at the end of the second multiplier 200 or between the two side rods at the end of the cathode 400. The arc-shaped end of the first multiplier 100 is fitted with the inner wall of the first limiting groove 2, and the arc-shaped end of the final multiplier 300 is fitted with the inner wall of the second limiting groove 3. A circular through hole 6 is provided at the center of the circular substrate 1. The first limiting groove 2 and the second limiting groove 3 are detachably mounted on the circular substrate 1 via the base 7. The first limiting part 4 and the second limiting part 5 are detachably mounted on the circular substrate 1. The first limiting part 4 includes four limiting posts 42 for limiting the four side rods at both ends of the second multiplier 200 or the four side rods at the end of the cathode 400. A flexible sealing strip 43 is provided on the circular substrate 1 for sealing the end of the second multiplier 200 or the end of the cathode 400.

[0022] Among them, the circular substrate 1 serves as the core support and installation base of the tooling and is the assembly carrier for all functional components. The circular through hole 6 set in the center of the circular substrate 1 is specifically used to adapt to the voltage device of the magnetron coating machine, ensuring precise connection between the tooling and the equipment circuit system, avoiding process fluctuations caused by poor circuit contact during the coating process, and providing installation space for the equipment rotation mechanism, ensuring stable rotation of the tooling during coating, and providing a foundation for film uniformity.

[0023] The circular substrate 1 is made of 304 stainless steel with a surface roughness controlled to Ra≤0.8μm and undergoes oxidation treatment, giving it excellent corrosion resistance and mechanical strength. Its outer diameter is designed to be 245mm and its thickness to be 20mm, ensuring sufficient structural strength to support the weight of multiple component mounting units and the pressure during the coating process. This also avoids equipment compatibility issues caused by excessive substrate thickness, allowing it to withstand various media corrosion in the vacuum coating environment and extending the tooling's service life.

[0024] The circular substrate 1 employs a circumferential array to arrange various limiting components, with the second limiting part 5, the second limiting groove 3, the first limiting part 4, and the first limiting groove 2 arranged sequentially from the center outwards. This layout optimizes space utilization efficiency, enabling a single fixture to simultaneously fix multiple photomultiplier tube components, significantly improving production efficiency. Simultaneously, the partitioned layout avoids mutual interference between different types of components during the coating process, ensuring that the sputtered particle stream uniformly covers the surface to be coated on each component. It also provides ample operating space for component loading and unloading, enhancing operational convenience. Furthermore, the circular structure itself perfectly matches the rotational trajectory of the magnetron sputtering machine, reducing the impact of centrifugal force during rotation and preventing component displacement during high-speed rotation, further ensuring positioning accuracy.

[0025] Arc-shaped part limiting components: The first limiting groove 2 and the second limiting groove 3 are dedicated limiting components designed for the arc-shaped structure of the first multiplier and the last multiplier. They correspond to the fixing requirements of the first multiplier 100 and the last multiplier 300, respectively. Their core function is to achieve precise positioning of the arc-shaped part and back-side anti-contamination protection.

[0026] The core design feature of the first limiting groove 2 lies in its precise structural matching with the first dynode 100. The arc-shaped end of the first dynode 100 fits snugly against the inner wall of the first limiting groove 2. The groove width can be 8.2 mm and the depth can be 10 mm. Through the tight fit between the inner wall and the arc-shaped end of the part, the displacement of the first dynode 100 can be restricted in both circumferential and radial dimensions. This prevents the part from loosening due to tooling rotation or particle flow impact during the coating process, ensuring that the front side of the part to be coated is always kept within the preset sputtering area, thus guaranteeing the accuracy of film deposition. At the same time, the groove depth of approximately 10 mm ensures that after the part is placed in the groove, the back and side edges are completely shielded by the inner wall of the groove, with only the front side fully exposed to the sputtering particle flow. This completely solves the problem of non-working surface contamination caused by the lack of back protection in traditional tooling. Tests have shown that the back contamination rate of the part can be reduced from 15% to below 1% after adopting this structure, effectively protecting the cleanliness of the non-working surface of the part and preventing the back coating from affecting the vacuum performance and electron emission efficiency of the photomultiplier tube.

[0027] The second limiting groove 3 is designed for the final stage derrick 300. Its working principle is the same as that of the first limiting groove 2, but its dimensional parameters are precisely matched to those of the final stage derrick 300. The groove width can be 8.0 mm and the depth can be 10 mm. Precise positioning is achieved through the tight fit between the arc-shaped end and the inner wall of the groove. In terms of anti-contamination effect, the second limiting groove 3 also completely blocks the back and side edges of the final stage derrick 300 through its depth design, leaving only the front side for coating. This completely blocks the contact between the sputtered particle stream and the non-working surface of the part, ensuring that the secondary electron emission performance of the final stage derrick 300 is not affected by contamination. In addition, both the second limiting groove 3 and the first limiting groove 2 are detachably mounted on the circular substrate 1 via the base 7. When it is necessary to adapt to different models of first multiplier or final multiplier, the corresponding groove assembly can be directly replaced without replacing the entire tooling, which greatly improves the versatility and flexibility of the tooling, reduces production costs, and facilitates the maintenance and replacement of the grooves. When the inner wall of the groove is worn or contaminated due to long-term use, it can be quickly disassembled for cleaning or replacement, ensuring the stability of the limiting accuracy and anti-contamination effect.

[0028] Planar part limiting components: The first limiting part 4 and the second limiting part 5 are specifically used to fix the planar parts of the cathode and the second dynode. They have the same structure and respectively undertake the limiting function of the second dynode 200 and the cathode 400. Their core function is to achieve stable clamping of the planar parts, while blocking the non-working surface to prevent coating contamination.

[0029] The first limiting part 4 has two structural forms to adapt to the fixing requirements of planar parts in different scenarios. Both structures are designed around the core goal of "precise positioning + back protection". The first structure consists of two opposing first baffles 41, with a height and thickness of 2mm, forming a precise clamping space. The first baffles 41 are placed between the two side rods at the end of the second dynode 200 or the two side rods at the end of the cathode 400. The clamping force of the two side baffles achieves axial and radial positioning of the part. This not only firmly fixes the planar part and avoids displacement caused by the rotation of the tooling during the coating process, but also prevents the front side of the part from being coated due to excessive height or thickness of the baffles. The 2mm height design just covers the non-working area of ​​the edge of the part, and the 2mm thickness ensures structural strength while minimizing obstruction of the sputtered particle stream, ensuring that the front side of the part can fully receive the coating material and ensuring the uniformity of the film layer.

[0030] More importantly, the shielding effect of the first baffle 41 directly solves the problem of back-side contamination of planar parts. By shielding the ends of the second dynode and cathode 400, sputtered particle streams can be prevented from penetrating from the edge of the part to the back side. At the same time, the area where the part is attached to the surface of the circular substrate 1 is also protected from back-side contamination by the substrate itself, forming a dual protection structure of "baffle + substrate". This effectively prevents the non-working surface from being contaminated by the coating material, ensuring that the photoelectric conversion efficiency of the cathode and the secondary electron emission performance of the second dynode are not affected.

[0031] The second structure uses four limiting posts 42 in conjunction with a flexible sealing strip 43. This design optimizes the end-edge limiting requirements of planar parts, further improving positioning accuracy and anti-contamination effect. The four limiting posts 42 correspond to the four edge rods at the ends of the second derrick 200 or cathode 400, achieving omnidirectional fixation of the part through precise point-to-point limiting. Compared to the baffle structure, the limiting posts 42 have a smaller contact area, less impact on the sputtered particle flow, and higher limiting accuracy, effectively preventing minor displacement of the part during clamping. The flexible sealing strip 43 on the circular substrate 1 is specifically used to seal the ends of the second derrick 200 or cathode 400. This design further enhances the anti-contamination function: the flexible sealing strip 43 can tightly fit the gaps at the ends of the part, completely blocking the penetration path of the sputtered particle flow, solving the gap-induced plating problem that may exist in the baffle structure, and minimizing the risk of back-side contamination. At the same time, the choice of flexible material avoids scratches on the part surface, ensuring the original precision of the part, which is crucial for the production of high-precision devices such as photomultiplier tubes.

[0032] The second limiting part 5 has the same structure as the first limiting part 4 and is specifically used to limit the cathode 400. Its function is synergistic with that of the first limiting part 4, jointly achieving comprehensive fixation and protection of the planar part. In terms of layout, the second limiting part 5 is located in the area closest to the center of the circular substrate 1. As the core component of the photomultiplier tube, the cathode 400 has extremely high coating precision requirements. The linear velocity of the position near the center is relatively stable when the tooling rotates, which can reduce the influence of centrifugal force on the positioning of the part, while ensuring a more uniform distribution of sputtered particle flow on the cathode surface and improving the film quality.

[0033] The two structural forms of the second limiting part 5 are also adapted to the fixing requirements of the cathode 400: for cathodes of standard size, two first baffles 41 are used to form a clamping space to achieve rapid positioning and basic protection; for cathodes with high precision requirements, a structure of four limiting posts 42 combined with flexible sealing strips 43 is used to achieve point-to-point precise limiting and gap sealing, ensuring the uniformity of the coating on the cathode surface and the cleanliness of the back side. In addition, the second limiting part 5 adopts a detachable design, which can quickly replace the limiting components according to the size requirements of different cathode models, improve the versatility of the tooling, and facilitate maintenance and replacement, ensuring positioning accuracy and anti-contamination effect during long-term use.

[0034] The substrate 7, serving as the mounting carrier for the first limiting groove 2 and the second limiting groove 3, is the core component for realizing the detachable function of the grooves. Its effectiveness lies in the versatility of the tooling, ease of maintenance, and structural stability. By detachably connecting the first limiting groove 2 and the second limiting groove 3 to the circular substrate 1 through the substrate 7, when it is necessary to replace the grooves of different specifications to adapt to the new model of the first dynode 100 or the final dynode 300, it is not necessary to replace the entire tooling. Only the substrate 7 needs to be disassembled to replace the groove assembly, which greatly reduces the manufacturing and usage costs of the tooling, while improving production flexibility and enabling rapid response to the production needs of different customers or different products.

[0035] The connection method of the substrate 7 meets the requirements of the vacuum coating environment, ensuring that the first limiting groove 2 and the second limiting groove 3 will not loosen or shift during the high-speed rotation and high-temperature baking of the tooling. The substrate 7 and the circular substrate 1 adopt a high-precision assembly process, which is tight and firm, and can withstand the mechanical stress and temperature changes during the coating process, ensuring the fitting accuracy of the grooves and parts, and avoiding positioning deviations and anti-contamination failures caused by loose connections. In addition, the substrate 7 is made of 304 stainless steel, consistent with the circular substrate 1, to ensure the corrosion resistance and vacuum performance of the overall structure, avoiding chemical reactions or contamination caused by material differences. At the same time, its surface treatment standard meets the requirement of Ra≤0.8μm, reducing the impact on the coating environment.

[0036] The flexible sealing strip 43 is an important auxiliary component of the first limiting part 4 and the second limiting part 5. It is specifically used to seal the end of the second dynode 200 or the end of the cathode 400. Its function is to strengthen the anti-pollution protection of the planar parts and fill the gaps and loopholes in the limiting structure.

[0037] The flexible sealing strip 43 possesses excellent compatibility and protection: its soft material will not scratch or deform the ends of parts, ensuring the original precision of the parts, which is especially important for components like the cathode 400 that have extremely high surface quality requirements; its high temperature and vacuum resistance can withstand the 220℃ baking temperature and high vacuum environment during the coating process, without deforming, aging, or releasing harmful substances due to process conditions, ensuring the safety and stability of the coating process. Furthermore, the flexible sealing strip 43 features a detachable design for easy replacement and cleaning. When wear or contamination occurs after long-term use, it can be quickly disassembled and replaced to maintain its sealing and protective effect, extending the overall service life of the tooling.

[0038] Work process: First, a circular substrate 1 is fixed to the rotating tray of the magnetron sputtering coating equipment. Its central circular through-hole 6 is adapted to the equipment's voltage device, ensuring circuit connection and stable rotation. Then, the cleaned and degassed parts are sorted and installed: the first dynode 100 is embedded in the first limiting groove 2, with its arc-shaped end fitting against the inner wall of the groove; the final dynode 300 is placed in the second limiting groove 3, precisely positioned using its specific dimensions. For planar parts, the second dynode 200 is fixed by the first limiting part 4, which can be held by double first baffles 41 or positioned by four limiting posts 42; the cathode 400 is fixed by the second limiting part 5, with a flexible sealing strip 43 sealing the end gaps. After all parts are installed, the equipment is started by setting the baking temperature to 220℃ for 30 minutes and the film thickness parameters. The fixture rotates with the rotating mechanism, and the sputtered particle stream evenly covers the exposed front of the parts. The grooves, baffles, and sealing strips form multiple layers of protection, preventing contamination of the back and side edges, ultimately completing the simultaneous and precise coating of multiple sets of parts.

[0039] The embodiments of this utility model have been described in detail above, but the content described is only a preferred embodiment of this utility model and should not be considered as limiting the scope of implementation of this utility model. All equivalent changes and improvements made in accordance with the claims of this utility model should still fall within the patent coverage of this utility model.

Claims

1. A coating fixture for photomultiplier tube components, characterized in that, include: A circular substrate (1) is provided with a plurality of first limiting grooves (2) for limiting the first multiplier (100), a plurality of second limiting grooves (3) for limiting the final multiplier (300), a plurality of first limiting portions (4) for limiting the second multiplier (200), and a plurality of second limiting portions (5) for limiting the cathode (400).

2. The photomultiplier tube component coating fixture according to claim 1, characterized in that, Multiple first limiting grooves (2), multiple second limiting grooves (3), multiple first limiting parts (4) and multiple second limiting parts (5) are arranged in a circumferential array on the circular substrate (1).

3. The photomultiplier tube component coating fixture according to claim 1, characterized in that, The first limiting part (4) and the second limiting part (5) have the same structure.

4. The photomultiplier tube component coating fixture according to claim 2, characterized in that, The circular substrate (1) is provided with a second limiting part (5), a second limiting groove (3), a first limiting part (4), and a first limiting groove (2) arranged sequentially from the center outwards.

5. The photomultiplier tube component coating fixture according to claim 4, characterized in that, The first limiting part (4) includes two first baffles (41) disposed on the circular substrate (1). The first baffles (41) are positioned between the two side rods at the end of the second multiplier (200) or between the two side rods at the end of the cathode (400).

6. The photomultiplier tube component coating fixture according to claim 1, characterized in that, The arc-shaped end of the first multiplier (100) is in contact with the inner wall of the first limiting groove (2), and the arc-shaped end of the last multiplier (300) is in contact with the inner wall of the second limiting groove (3).

7. The photomultiplier tube component coating fixture according to claim 1, characterized in that, A circular through hole (6) is provided at the center of the circular substrate (1).

8. The photomultiplier tube component coating fixture according to claim 1, characterized in that, The first limiting groove (2) and the second limiting groove (3) are respectively detachably mounted on the circular substrate (1) via the base (7).

9. The photomultiplier tube component coating fixture according to claim 1, characterized in that, The first limiting part (4) and the second limiting part (5) are detachably mounted on the circular substrate (1).

10. The photomultiplier tube component coating fixture according to claim 3, characterized in that, The first limiting part (4) includes four limiting posts (42) for limiting the four side rods at both ends of the second multiplier (200) or the four side rods at the end of the cathode (400). The circular substrate (1) is provided with a flexible sealing strip (43) for sealing the end of the second multiplier (200) or the end of the cathode (400).

Images