Optical detector potting method and potting tool

Abstract

The invention relates to the technical field of optical detectors, and provides an optical detector potting method and a potting tool. The optical detector potting method comprises the following steps: S110, potting a pretreated glue solution into an annular gap to obtain a first potting assembly, and sealing and buckling an upper half cabin body to a lower half cabin body to obtain a second potting assembly; s120, negative pressure pumping is conducted on the interior of the second filling and sealing assembly till the pressure reaches the first set pressure intensity, and pressure maintaining is conducted for the first set duration according to the pressure intensity; s130, after pressure maintaining is completed, pressure maintaining aftertreatment is conducted; repeating the step S110 to the step S130 for N times until the annular gap is filled with the glue solution; after the first to (N-1) th pressure maintaining is completed, gradually releasing vacuum within a second set time period to gradually recover the interior of the glass ball cabin to the standard atmospheric pressure, and after the Nth pressure maintaining is completed, gradually releasing vacuum within a third set time period to gradually recover the interior of the glass ball cabin to the second set pressure intensity, and maintaining the pressure for a fourth set time period, the pressure intensity of the second set pressure intensity is greater than the first set pressure intensity.

Description

Technical Field

[0001] This invention relates to the field of optical detector technology, and in particular to an optical detector potting method and potting fixture. Background Technology

[0002] In existing technologies, the optical detectors of large deep-sea neutrino telescopes require placing photomultiplier tubes (PMTs) within a borosilicate glass sphere of a set diameter (e.g., 600 mm). High-viscosity two-component optical silicone is then poured into the narrow annular gap (typically only a few millimeters) between the PMT and the glass sphere to achieve refractive index matching. Because a magnetic shielding mesh is placed within the gap, the interface environment is complex, making it prone to bubble formation during silicone potting. This reduces the optical transmittance of the detector, creates scattering centers in the optical path, and leads to signal distortion and a decrease in signal-to-noise ratio. Furthermore, the high viscosity of the silicone makes it difficult to completely wet the metal mesh and glass surface during flow. The mesh structure hinders silicone flow, creating localized air traps. Additionally, the silicone is constrained by the interface during curing, easily generating internal stress gradients, leading to localized refractive index drift and deteriorating refractive index uniformity.

[0003] To address these issues, related technologies, building upon traditional stepped curing and vacuum static degassing, utilize segmented heating to release stress and accelerate bubble rupture through dynamic gas pressure circulation or high-frequency vibration. This shortens degassing time and reduces residual bubbles. However, these technologies still require specialized equipment and are difficult to adapt to mass production needs. Furthermore, silane coupling agent treatment cannot completely overcome delamination problems caused by thermal mismatch at the metal-silicone-glass interface. Summary of the Invention

[0004] This invention provides an optical detector potting method and potting fixture to solve the defects of existing technologies, such as incomplete bubble elimination, poor metal mesh interface wetting, high risk of interface delamination, and low efficiency of large-volume potting processes.

[0005] The present invention provides an optical detector potting method, comprising the following steps.

[0006] S110. The pretreated adhesive is filled into the annular gap between the lower half of the glass sphere and the photomultiplier tube to obtain the first potting assembly. The upper half of the glass sphere is then sealed and fastened to the lower half of the glass sphere to obtain the second potting assembly.

[0007] S120. The inside of the second potting assembly is drawn into negative pressure and held at a first set pressure for a first set time to expel air bubbles from inside the adhesive and at the adhesive interface.

[0008] S130. After the second potting assembly has been pressurized, the second potting assembly is subjected to post-pressurization processing.

[0009] Repeat steps S110 to S130N times until the annular gap is filled with adhesive, where N is a positive integer greater than or equal to 2.

[0010] After the first to N-1 pressure holding cycles are completed, the vacuum is gradually released within a second set time period, allowing the interior of the glass sphere to gradually return to standard atmospheric pressure. After the Nth pressure holding cycle is completed, the vacuum is gradually released within a third set time period, allowing the interior of the glass sphere to gradually return to the second set pressure, and then pressure is maintained for a fourth set time period. The pressure of the second set pressure is greater than the pressure of the first set pressure.

[0011] According to the optical detector potting method provided by the present invention, the first set pressure is -0.1 MPa to -0.08 MPa, and the first set duration is 30 min to 60 min; the second set pressure is -0.05 MPa to -0.04 MPa, and the second set duration is 1 min to 10 min; the third set duration is 30 min to 60 min; and the fourth set duration is greater than or equal to 12 h.

[0012] According to the optical detector potting method provided by the present invention, the first set pressure is -0.08 MPa, the first set duration is 30 min, the second set duration is 1 min, the third set duration is 30 min, and the fourth set duration is 12 h.

[0013] According to the optical detector potting method provided by the present invention, after gradually releasing the vacuum within a third set time period to gradually restore the interior of the glass sphere to a second set pressure and maintaining the pressure for a fourth set time period, the method further includes the following steps.

[0014] The vacuum is gradually released within the fifth set time period, allowing the interior of the glass sphere to gradually return to standard atmospheric pressure.

[0015] According to the optical detector potting method provided by the present invention, after gradually releasing the vacuum within a fifth set time period to gradually restore the interior of the glass sphere to standard atmospheric pressure, the method further includes the following steps.

[0016] The second potting assembly, after potting, should be left to stand for 7 days or more.

[0017] According to the optical detector potting method provided by the present invention, the pretreatment of the adhesive solution includes the following steps.

[0018] The set amounts of silicone A component vinyl silicone oil and B component hydrogen-containing silicone oil are mixed and stirred for the first time to obtain the first mixed adhesive solution.

[0019] The first mixed adhesive solution is mixed and stirred a second time to obtain the second mixed adhesive solution.

[0020] The second mixed adhesive solution is pre-degassed under a vacuum environment with a first set pressure.

[0021] According to the optical detector potting method provided by the present invention, the step of pre-degassing the second mixed adhesive solution under a vacuum environment with a third set pressure includes the following steps.

[0022] The second mixed adhesive solution was held under vacuum at a pressure of -0.1 MPa to -0.06 MPa for 3 minutes or longer.

[0023] Another aspect of the present invention provides an optical detector potting fixture for implementing the optical detector potting method described above, comprising: a support frame, a horizontal support assembly, a disc support, and a gap adjustment assembly.

[0024] The support frame supports the glass dome; the horizontal support assembly includes a fixing ring and multiple scales, the fixing ring being configured horizontally along the upper edge of the lower half of the glass dome, and the multiple scales being circumferentially spaced on the support frame to calibrate the tilt angle of the fixing ring relative to the horizontal plane; the disc bracket is connected to the fixing ring and is configured to be fixedly connected to the Kovar metal disc of the photomultiplier tube; the gap adjustment assembly is connected to the support frame and is used to vertically adjust the annular gap between the lower half of the glass dome and the photomultiplier tube.

[0025] According to the optical detector potting fixture provided by the present invention, the gap adjustment assembly includes a guide rail and a slider, one of the guide rail and the slider being connected to the fixing ring, and the other being connected to the disc support.

[0026] According to the optical detector potting fixture provided by the present invention, the gap adjustment assembly further includes a threaded locking member, which is threadedly connected to the slider to lock the sliding engagement position of the guide rail and the slider.

[0027] The optical detector potting method provided by this invention employs a cyclical strategy of multi-stage adhesive injection, gradient vacuum degassing, and final low-pressure curing. This allows the adhesive to fully wet the metal shielding mesh and glass / PMT interface under low stress, gradually removing deep air bubbles and suppressing microbubble regeneration. Furthermore, the final (Nth) pressure is maintained for an extended period at a second set pressure higher than the first set pressure, prolonging the low viscosity period of the adhesive and releasing curing shrinkage stress. This simultaneously achieves bubble-free adhesive layers and delamination-free interfaces, improving optical coupling reliability and detector lifespan.

[0028] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0030] Figure 1 This is a schematic flowchart of the optical detector potting method provided in an embodiment of the present invention.

[0031] Figure 2 This is a schematic diagram of the operation flow of the optical detector potting method provided in the embodiment of the present invention.

[0032] Figure 3 This is a schematic diagram of the working state of the optical detector potting fixture provided in the embodiment of the present invention.

[0033] Figure 4 This is an exploded view of the optical detector potting fixture provided in the embodiment of the present invention in its working state.

[0034] Figure label: 100. Support frame; 200. Horizontal support assembly; 210. Fixing ring; 220. Scale; 300. Disc bracket; 400. Gap adjustment assembly; 410. Guide rail; 420. Slider; 430. Threaded locking component; 500. Glass sphere; 510. Lower half of the chamber; 520. Upper half of the chamber; 600. Photomultiplier tube; 700. Annular gap; 800. Magnetic shielding mesh. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0036] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention 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. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0037] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention according to the specific circumstances.

[0038] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0039] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0040] The following is combined Figures 1 to 4 This invention describes the optical detector potting method and potting fixture provided by the present invention.

[0041] See Figure 1 and Figure 2 As shown, the optical detector potting method provided in this embodiment of the invention includes the following steps.

[0042] S110. The pretreated adhesive is potted into the annular gap 700 between the lower half of the glass sphere 500 and the photomultiplier tube 600 to obtain the first potting assembly. The upper half of the glass sphere 500 is sealed and fastened to the lower half of the glass sphere 500 to obtain the second potting assembly.

[0043] S120. The inside of the second potting assembly is drawn into negative pressure and held at a first set pressure for a first set time to expel air bubbles from inside the adhesive and at the adhesive interface.

[0044] S130. After the second potting assembly has been pressurized, the second potting assembly is subjected to post-pressurization treatment.

[0045] Repeat steps S110 to S130N times until the annular gap 700 is filled with adhesive, where N is a positive integer greater than or equal to 2.

[0046] After the first N-1 pressure holding cycles are completed, the vacuum is gradually released within a second set time period, allowing the interior of the glass sphere 500 to gradually return to standard atmospheric pressure. After the Nth (final) pressure holding cycle is completed, the vacuum is gradually released within a third set time period, allowing the interior of the glass sphere 500 to gradually return to the second set pressure, and then pressure is maintained for a fourth set time period. The pressure of the second set pressure is greater than that of the first set pressure.

[0047] The optical detector potting method provided by this invention employs a cyclical strategy of multi-stage adhesive injection, gradient vacuum degassing, and final low-pressure curing. This allows the adhesive to fully wet the metal shielding mesh and the glass / photomultiplier tube 600 interface under low stress, gradually removing deep air bubbles and suppressing microbubble regeneration. Furthermore, the final (Nth) pressure is maintained for an extended period at a second set pressure higher than the first set pressure, prolonging the low viscosity period of the adhesive and releasing curing shrinkage stress. This simultaneously achieves a bubble-free adhesive layer and no delamination at the interface, improving optical coupling reliability and detector lifespan.

[0048] Specifically, in step S110, the lower half of the glass spherical chamber 510 can be horizontally positioned using tooling, and then the photomultiplier tube 600 can be coaxially suspended in the cavity to form a uniformly distributed annular gap 700. Subsequently, the pre-treated (e.g., vacuum degassing) adhesive is slowly injected into the annular gap 700 along the chamber wall. After the first filling is completed, the upper half of the spherical chamber is immediately snapped together and sealed to obtain the second potting assembly that can be moved into the vacuum system as a whole.

[0049] In step S120, the second potting assembly is placed entirely into a vacuum environment (such as a vacuum chamber or vacuum barrel), connecting the vacuum environment with the interior of the glass bulb 500. A vacuum is then drawn to a set negative pressure (first set pressure) and maintained. Under this negative pressure, bubbles inside the adhesive and at the interface expand, burst, and float to the surface, significantly reducing the bubble content in the adhesive layer. At the first set pressure, most of the mixed air bubbles and the "flash vaporization" bubbles (manifesting as chain microbubbles) induced by stress concentration at the tips of the metal mesh due to drastic decompression expand and escape from the adhesive surface.

[0050] In step S130, after the first N-1 pressure holding cycles, the pressure is gradually released to atmospheric pressure within the second set time period to complete intermediate curing. After the final (Nth) pressure holding cycle, the pressure is released to a second set pressure higher than the first set pressure within the third set time period, and pressure is maintained for a fourth set time period. This allows the adhesive to fully flow, wet, and slowly complete final curing under low stress, thereby eliminating residual bubbles and inhibiting interfacial delamination. Specifically, maintaining a certain negative pressure environment can further promote the slow rise and discharge of deep micro-bubbles. This significantly extends the holding time of the silicone in a low viscosity (incompletely cured) state (the fourth set time is much longer than the conventional process), allowing the adhesive sufficient time to fully wet the surfaces of the metal mesh, glass, and photomultiplier tube 600 under low stress, greatly improving interfacial bonding. The slow curing process under low negative pressure helps to uniformly release the internal stress caused by the difference in the curing shrinkage and thermal expansion coefficient of the silicone, effectively inhibiting the occurrence of later delamination. After the fourth set time of pressure holding is completed, the vacuum is slowly released again to allow the vacuum level to smoothly return to the standard atmospheric pressure (normal pressure) of the room.

[0051] It should be noted that the number of potting and holding pressure cycles can be flexibly set based on the 700mm volume of the annular gap: the larger the volume, the more stages can be added to ensure that the amount of adhesive injected each time is moderate, the air bubble venting path is short, and the gradient vacuum treatment effect is better; conversely, a smaller volume can reduce the number of stages, balancing efficiency and potting quality. For example, when the potting and holding pressure cycles are twice, after the first holding pressure is completed, the pressure is gradually released to normal pressure within the second set time to achieve initial shaping and stress release; after the second holding pressure is completed, the pressure is released to a second set pressure higher than the first set pressure within the third set time, and the pressure is maintained for a fourth set time to allow the adhesive to complete the final curing in a low-stress environment, ensuring no air bubble residue and effectively preventing interface delamination.

[0052] The first set pressure, the second set pressure, the first set time, the second set time, the third set time, and the fourth set time can all be adaptively adjusted according to the type of adhesive, viscosity, curing characteristics, the size of the annular gap 700, and the complexity of the metal shielding mesh structure to ensure that air bubbles are fully expelled, the adhesive layer is completely filled, and there is no delamination at the interface. No special limitations are imposed on these settings.

[0053] According to some embodiments of the present invention, the first set pressure is -0.1 MPa to -0.08 MPa, and the first set duration is 30 min to 60 min.

[0054] By controlling the first set pressure between -0.1MPa and -0.08MPa and maintaining it for 30 to 60 minutes, sufficient expansion-rupture time can be provided for the bubbles inside the adhesive and at the interface, ensuring that deep bubbles are fully released and providing a uniform adhesive layer with low bubble content for subsequent filling and curing.

[0055] Specifically, within this negative pressure range, the viscosity of the adhesive decreases significantly, the critical size of the bubbles increases, and they are more likely to break through the anchoring effect of the metal mesh and float continuously.

[0056] As an example, the first set pressure can be -0.1 MPa, -0.09 MPa, or -0.08 MPa, with -0.08 MPa being preferred. The first set duration can be 30 min, 40 min, 50 min, or 60 min, with 30 min being preferred.

[0057] According to some embodiments of the present invention, the second set duration is 1 min to 10 min.

[0058] By controlling the second set time between 1 minute and 10 minutes, the vacuum release rate can be kept gradual, avoiding the formation of eddies or bubble backflow on the surface and inside of the adhesive due to sudden changes in pressure difference, ensuring that the discharged gas no longer remains, and the adhesive layer structure can be stably transitioned to the normal pressure state.

[0059] As an example, the second set duration can be 1 minute, 2 minutes, 5 minutes, or 10 minutes, etc.

[0060] According to some embodiments of the present invention, the second set pressure is -0.05MPa to -0.04MPa, the third set duration is 30min to 60min, and the fourth set duration is greater than or equal to 12h.

[0061] By controlling the second set pressure between -0.05MPa and -0.04MPa, and then steadily reducing it to this negative pressure range within a third set time of 30min to 60min, and then maintaining the pressure for at least 12h (12h is much longer than conventional processes), the adhesive can be fully leveled and wetted at the interface between the metal shielding mesh and the glass / photomultiplier tube 600 under low stress and low viscosity conditions. This greatly improves the interface bonding effect, slowly releases the curing shrinkage stress, effectively inhibits microbubble regeneration and interface delamination, and achieves a final curing effect with a dense adhesive layer and stable optical performance.

[0062] As an example, the second set pressure can be -0.05 MPa, -0.5 standard atmospheres (approximately -0.0505 MPa), or -0.04 MPa, etc., preferably -0.5 standard atmospheres. The third set duration can be 30 min, 40 min, or 60 min, etc., preferably 30 min. The fourth set duration can be 12 h, 15 h, or 20 h, etc., preferably 12 h.

[0063] According to some embodiments of the present invention, after gradually releasing the vacuum within a third predetermined time period to gradually restore the interior of the glass sphere chamber 500 to a second predetermined pressure and maintaining the pressure for a fourth predetermined time period, the following steps are also included.

[0064] The vacuum is gradually released within the fifth set time period, allowing the interior of the glass sphere 500 to gradually return to standard atmospheric pressure.

[0065] After the glass sphere 500 is held at the second set pressure for the fourth set time, the vacuum is gradually released within the fifth set time, allowing the interior of the glass sphere 500 to gradually return to the standard atmospheric pressure. This allows the interior of the glass sphere 500 to smoothly rise back to the standard atmospheric pressure, avoiding the collapse of the adhesive layer surface or the reabsorption of air bubbles caused by sudden pressure changes. This ensures that the cured silicone adheres tightly to the interfaces of the glass, metal mesh, and photomultiplier tube 600, ultimately obtaining a dense and defect-free optical coupling adhesive layer.

[0066] As an example, the fifth setting duration can be 1 minute, 2 minutes, 5 minutes or 10 minutes, with 1 minute being preferred.

[0067] According to some embodiments of the present invention, after gradually releasing the vacuum within a fifth predetermined time period to gradually restore the interior of the glass sphere 500 to standard atmospheric pressure, the following steps are also included.

[0068] Allow the second potting assembly to stand for 7 days or more after potting is completed.

[0069] By allowing the second potting assembly, which has undergone vacuum recovery, to stand at standard atmospheric pressure for no less than 7 days, the adhesive can fully complete the post-curing reaction at room temperature, further releasing residual stress and stabilizing the refractive index, ensuring that the optical performance and interfacial bonding strength meet the reliability requirements for long-term deep-sea use.

[0070] As an example, the second potting assembly can be left to stand at standard atmospheric pressure for 7 days, 10 days, or 14 days, preferably 7 days.

[0071] According to some embodiments of the present invention, the pretreatment of the adhesive includes the following steps.

[0072] The set amounts of silicone A component vinyl silicone oil and B component hydrogen-containing silicone oil are mixed and stirred for the first time to obtain the first mixed adhesive solution.

[0073] The first mixed adhesive solution is mixed and stirred a second time to obtain the second mixed adhesive solution.

[0074] The second mixed adhesive solution is pre-degassed under a vacuum environment with a third set pressure.

[0075] By mixing and stirring the silicone components A and B twice in sequence, and then pre-degassing them under a vacuum environment with a third set pressure, it can be ensured that the adhesive is uniform and free of lumps, and the air mixed in can be removed in advance, providing a low-bubble and highly consistent adhesive base for subsequent potting.

[0076] According to some embodiments of the present invention, the second mixed adhesive is pre-degassed in a vacuum environment with a third set pressure, including the following steps.

[0077] The second mixed adhesive solution was held under vacuum at a pressure of -0.1 MPa to -0.06 MPa for 3 minutes or longer.

[0078] By placing the second mixed adhesive solution in a vacuum environment of -0.1MPa to -0.06MPa for at least 3 minutes, the air bubbles trapped inside the adhesive solution can be fully expanded, broken, and escaped, achieving pre-degassing and significantly reducing the initial air content, thus laying a low-bubble base material for subsequent vacuum potting.

[0079] As an example, the third set pressure can be -0.1 MPa, -0.08 MPa or -0.06 MPa, etc., preferably -0.08 MPa, and the pressure holding time can be 3 min, 5 min or 10 min, etc., preferably 3 min.

[0080] The optical detector potting fixture provided by the present invention will be described below. The optical detector potting fixture described below can be referred to in correspondence with the optical detector potting method described above.

[0081] See Figure 3 and Figure 4 As shown, the optical detector potting fixture provided in this embodiment of the invention is used to implement the optical detector potting method described above, and includes: a support frame 100, a horizontal support assembly 200, a disc support 300, and a gap adjustment assembly 400.

[0082] The support frame 100 supports the glass sphere 500; the horizontal support assembly 200 includes a fixing ring 210 and multiple scales 220. The fixing ring 210 is configured to be horizontally positioned on the upper edge of the lower half of the glass sphere 500, and the multiple scales 220 are spaced circumferentially on the support frame 100 to calibrate the tilt angle of the fixing ring 210 relative to the horizontal plane; the disc bracket 300 is connected to the fixing ring 210 and is configured to be fixedly connected to the Kovar metal disc of the photomultiplier tube 600; the gap adjustment assembly 400 is connected to the support frame 100 and is used to vertically adjust the annular gap 700 between the lower half of the glass sphere 500, the lower half of the glass sphere 500, and the photomultiplier tube 600.

[0083] The optical detector potting fixture provided by this invention, through the coordination of the support frame 100, the horizontal support component 200, the disc bracket 300 and the gap adjustment component 400, can achieve coaxial positioning and horizontal calibration of the glass sphere 500 and the photomultiplier tube 600, and can precisely control the width of the annular gap 700 in the vertical direction, ensuring uniform flow of adhesive and smooth discharge of air bubbles during the potting process, thereby improving the potting quality and detector reliability.

[0084] Specifically, the support frame 100 supports the lower half of the glass bulb 500, 510, and, in conjunction with the gap adjustment component 400, precisely adjusts the vertical position of the bulb, ensuring a uniform annular gap 700 and providing a stable geometric basis for subsequent adhesive injection and air bubble removal. The horizontal support component 200 adjusts and locks the upper edge of the lower half of the glass bulb 500, 510, to a horizontal position. The tilt angle is displayed in real time through the cooperation of the fixing ring 210 and the scale 220, ensuring that the annular gap 700 is circumferentially uniform during subsequent photomultiplier tube 600 installation and adhesive injection, avoiding uneven adhesive layer thickness and air bubble retention. The disc bracket 300 is fixedly connected to the Kovar metal disc of the photomultiplier tube 600 and, through a rigid connection with the fixing ring 210, maintains the coaxial position of the photomultiplier tube 600 and the glass bulb 500, preventing the photomultiplier tube 600 from shifting or tilting due to buoyancy or vibration during injection, thereby maintaining the uniformity of the annular gap 700 and the injection accuracy. The gap adjustment component 400 is used to vertically and synchronously raise and lower the lower half of the glass spherical chamber 500 510, precisely adjust and maintain the width of the annular gap 700 between the chamber and the photomultiplier tube 600, and ensure that the gap is uniform throughout the potting process, providing a reliable geometric guarantee for uniform flow of adhesive and smooth discharge of air bubbles.

[0085] See Figure 3 and Figure 4 As shown, according to some embodiments of the present invention, the gap adjustment assembly 400 includes a guide rail 410 and a slider 420, one of which is connected to a retaining ring 210 and the other is connected to a disc support 300.

[0086] By setting the gap adjustment component 400 to include a guide rail 410 and a slider 420, the guide rail 410 can precisely guide the slider 420, so that only a controllable vertical degree of freedom of movement is retained between the glass bulb 500 and the disc support 300, thereby achieving continuous fine adjustment of the annular gap 700. This ensures uniform gap and avoids circumferential offset, improving potting accuracy and operating efficiency.

[0087] Specifically, in this embodiment, there are two guide rails 410 and two sliders 420. The two guide rails 410 are connected to the fixing ring 210 through corresponding potting brackets, and the two sliders 420 are arranged opposite each other on both sides of the disc bracket 300. During adjustment, it is only necessary to control the sliders 420 to move vertically along the guide rails 410. Its structure is simple and easy to operate.

[0088] See Figure 3 and Figure 4 As shown, according to some embodiments of the present invention, the gap adjustment assembly 400 further includes a threaded locking member 430, which is threadedly connected to the slider 420 to lock the sliding engagement position of the guide rail 410 and the slider 420.

[0089] By setting the threaded locking part 430, after the gap adjustment is completed, the position of the slider 420 and the photomultiplier tube 600 can be fixed by the threaded locking part 430, thereby fixing the gap between the photomultiplier tube 600 and the glass sphere 500, preventing displacement due to buoyancy or vibration during the pouring and curing process, ensuring that the annular gap 700 always maintains the preset value, and ensuring uniform adhesive layer thickness and stable potting quality.

[0090] The following is an example illustrating the specific operation process of applying the optical detector potting fixture provided by this invention to the optical detector potting method. (See attached diagram) Figures 1 to 4 As shown.

[0091] (1) Place the glass sphere 500 and the magnetic shielding mesh 800 into DMM (Dimethoxymethane) solvent for ultrasonic cleaning. After cleaning, allow the photomultiplier tube 600 and the magnetic shielding mesh 800 to dry thoroughly.

[0092] (2) Place the lower half of the glass sphere 500, 510, on the support frame 100. Use the cross and horizontal support assembly 200 to adjust the lower half of the glass sphere 500, 510, to a horizontal position. See [reference needed]. Figure 2 As shown in Figure a.

[0093] (3) Place the magnetic shielding mesh 800 into the lower half of the glass sphere 500, 510, and adjust it to be parallel to the edge of the lower half of the glass sphere 500, see [reference]. Figure 2 As shown in Figure a.

[0094] (4) Fix the fixing ring 210 to the valveable metal disc of the photomultiplier tube 600 via the pressure plate, and fix the fixing ring 210 to the slider 420 via the adapter plate. See Figure 2 As shown in b.

[0095] (5) Install a potting support. The scale 220 on the support frame 100 can make the potting support coaxial with the lower half of the glass dome 500 510. See [reference] Figure 2 As shown in c.

[0096] (6) Place the photomultiplier tube 600 into the lower half of the glass sphere 500, with the sliders 420 on both sides slidingly engaged with the guide rails 410 on the potting bracket. Lock the tail of the photomultiplier tube 600 with the disc bracket 300 to prevent deflection, and lift it vertically by 5mm. The gap between the photomultiplier tube 600 and the lower half of the glass sphere 500 is an annular gap 700 (silicone filling channel). See [reference needed]. Figure 2 As shown in d.

[0097] (7) Pretreatment of silicone adhesive: Take the predetermined amounts of silicone components A and B (depending on the volume of the 700mm annular gap), transfer components A and B to a mixing container for the first mixing and stirring for 3 minutes. Transfer the pre-mixed adhesive to another clean container for the second mixing and stirring for 5 minutes to ensure thorough and uniform mixing. Place the mixed adhesive into a vacuum chamber for pre-degassing, achieving a vacuum degree of -0.08MPa, and maintain for 5 minutes. After completion, remove and set aside.

[0098] (8) First potting and deep degassing: The mixed and degassed silicone adhesive is slowly poured into the annular gap 700 between the fixed glass sphere 500 and the photomultiplier tube 600 to obtain the first potting assembly. After potting, the upper half 520 and the lower half 510 of the glass sphere 500 are sealed and fastened to obtain the second potting assembly. The inside of the glass sphere 500 is evacuated to -0.08MPa and held for 30 minutes. Under this vacuum state, most of the mixed air bubbles and the "flash vaporization" bubbles (manifested as a series of microbubbles) induced by stress concentration at the tips of the metal mesh due to the severe decompression will expand and escape from the surface of the adhesive.

[0099] After the pressure holding period, the vacuum is released very slowly (controlling the release rate, approximately 1 minute), allowing the vacuum level to smoothly return to the standard atmospheric pressure (normal pressure). Specifically, as the pressure gradually increases, the flash vaporization bubbles generated by the localized negative pressure in the previous step will dissolve again or collapse and disappear. Observe and confirm that the bubbles in the potting gap have completely disappeared.

[0100] (9) Second potting and deep degassing: Remove the upper half of the glass sphere 500, 520, and slowly pour the mixed and degassed silicone sealant into the component that has been potted for the first time and confirmed to be free of bubbles. Then, evacuate the internal pressure of the glass sphere 500 to -0.08 MPa again. Maintain the pressure for 30 minutes. Ensure that any mixed bubbles and any flash vaporization bubbles that may be generated are fully released. After the pressure holding period, slowly release the vacuum. Do not directly restore to normal pressure; instead, first adjust the vacuum to -0.5 atmospheres (absolute pressure approximately 50 kPa), and maintain the pressure at -0.5 atm for 12 hours.

[0101] During this process, maintaining a certain negative pressure environment can continue to promote the slow rise and expulsion of deep micro-bubbles. This significantly extends the holding time of the silicone in a low-viscosity (incompletely cured) state (12 hours, much longer than conventional processes), allowing the silicone sufficient time to fully wet the surfaces of the metal mesh, glass, and photomultiplier tube 600 under low stress, greatly improving the interfacial bonding. Simultaneously, the slow curing process under low negative pressure also helps to uniformly release the internal stress caused by the difference in the silicone's curing shrinkage and thermal expansion coefficients, effectively inhibiting later delamination. After 12 hours of pressure holding, the vacuum is slowly released again, allowing the vacuum level to smoothly return to the standard atmospheric pressure (normal pressure), and the support is then removed.

[0102] (10) Final curing: Place the potted photomultiplier tube 600 and glass sphere assembly (together with the support) horizontally in a clean environment. Remove them the next day and let them stand for 7 days to allow the silicone to complete a thorough post-curing process, ensuring the final mechanical and optical properties are achieved. After complete curing, subsequent optical performance tests can be performed.

[0103] It should be noted that, Figure 2 The upper half of the glass dome 500 is not shown.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for potting an optical detector, characterized in that, include: S110. The pretreated adhesive is filled into the annular gap between the lower half of the glass sphere and the photomultiplier tube to obtain the first filling assembly. The upper half of the glass sphere is sealed and fastened to the lower half of the glass sphere to obtain the second filling assembly. S120. The inside of the second potting assembly is drawn into negative pressure and held at a first set pressure for a first set time to expel air bubbles from the inside of the adhesive and the adhesive interface. S130. After the pressure holding of the second potting assembly is completed, the second potting assembly is subjected to post-pressure holding processing. Repeat steps S110 to S130N times until the annular gap is filled with adhesive, where N is a positive integer greater than or equal to 2. After the first to N-1 pressure holding cycles are completed, the vacuum is gradually released within a second set time period, allowing the interior of the glass sphere to gradually return to standard atmospheric pressure. After the Nth pressure holding cycle is completed, the vacuum is gradually released within a third set time period, allowing the interior of the glass sphere to gradually return to the second set pressure, and then pressure is maintained for a fourth set time period. The pressure of the second set pressure is greater than the pressure of the first set pressure.

2. The optical detector potting method according to claim 1, characterized in that, The first set pressure is -0.1 MPa to -0.08 MPa, and the first set duration is 30 min to 60 min; The second set pressure is -0.05MPa to -0.04MPa, the second set duration is 1min to 10min, the third set duration is 30min to 60min, and the fourth set duration is greater than or equal to 12h.

3. The optical detector potting method according to claim 2, characterized in that, The first set pressure is -0.08 MPa, and the first set duration is 30 minutes; The second set duration is 1 minute, the third set duration is 30 minutes, and the fourth set duration is 12 hours.

4. The optical detector potting method according to claim 1, characterized in that, After gradually releasing the vacuum within the third predetermined time period, allowing the interior of the glass sphere to gradually return to the second predetermined pressure, and maintaining the pressure for the fourth predetermined time period, the process further includes: The vacuum is gradually released within the fifth set time period, allowing the interior of the glass sphere to gradually return to standard atmospheric pressure.

5. The optical detector potting method according to claim 4, characterized in that, After gradually releasing the vacuum within the fifth predetermined time period, allowing the interior of the glass sphere to gradually return to standard atmospheric pressure, the process further includes: The second potting assembly, after potting, should be left to stand for 7 days or more.

6. The method for potting an optical detector according to any one of claims 1 to 5, characterized in that, The pretreatment of the adhesive includes: The set amounts of silicone A component vinyl silicone oil and B component hydrogen-containing silicone oil were mixed and stirred for the first time to obtain the first mixed adhesive solution; The first mixed adhesive solution is mixed and stirred a second time to obtain the second mixed adhesive solution; The second mixed adhesive solution is pre-degassed under a vacuum environment with a third set pressure.

7. The optical detector potting method according to claim 6, characterized in that, The step of pre-degassing the second mixed adhesive solution under a vacuum environment with a third set pressure includes: The second mixed adhesive solution was held under vacuum at a pressure of -0.1 MPa to -0.06 MPa for 3 minutes or longer.

8. A potting fixture for an optical detector, characterized in that, For implementing the optical detector encapsulation method as described in any one of claims 1 to 7, comprising: Support frame, the support frame being used to support the glass sphere; A horizontal support assembly, comprising a fixing ring and a plurality of scales, wherein the fixing ring is configured to be horizontally positioned on the upper edge of the lower half of the glass dome, and the plurality of scales are spaced circumferentially on the support frame for calibrating the tilt angle of the fixing ring relative to the horizontal plane. A disc support, the disc support being connected to the fixing ring, the disc support being configured to be fixedly connected to the Kovar metal disc of the photomultiplier tube; A gap adjustment assembly, connected to the support frame, is used to vertically adjust the annular gap between the lower half of the glass sphere and the photomultiplier tube.

9. The optical detector potting fixture according to claim 8, characterized in that, The gap adjustment assembly includes a guide rail and a slider, one of which is connected to the fixed ring and the other is connected to the disc support.

10. The optical detector potting fixture according to claim 9, characterized in that, The gap adjustment assembly also includes a threaded locking member, which is threadedly connected to the slider to lock the sliding engagement position of the guide rail and the slider.

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