Preparation equipment and preparation process of extremely-small-size antimony ball with lead for dynode type photomultiplier evaporation source

Abstract

The invention relates to the technical field of photomultipliers, in particular to preparation equipment and a preparation process for a dynode type photomultiplier evaporation source extremely-small-size antimony ball with a lead, and the equipment comprises a box body which is internally provided with a first space and a second space which are relatively independent; the atmosphere adjusting system comprises a first gas source used for providing the first atmosphere gas for the first space and a second gas source used for providing the second atmosphere gas for the second space. Through the cooperation of lead stepping transmission, the quantitative powder supply component and the power supply system, the powder feeding-ball melting-moving-out process can be continuously executed, a traditional manual or batch operation mode is replaced, the production efficiency is improved, the high consistency of the antimony balls in size, weight and shape is guaranteed, and the production cost is reduced. High-consistency continuous production of the antimony balls with extremely small sizes is realized, and the performance uniformity and the yield of photomultiplier products are indirectly improved.

Description

Technical Field

[0001] This invention relates to the field of photomultiplier tube technology, and more specifically to the equipment and process for preparing extremely small-sized leaded antimony spheres for evaporation sources of dynamo photomultiplier tubes. Background Technology

[0002] Photomultiplier tubes (PMTs) are electronic vacuum devices that amplify weak light signals and convert them into electrical signals for photoelectric detection. They are widely used in medical analytical instruments, radiation measurement, environmental monitoring, high-energy physics, and oil well logging. A dinoflag photomultiplier tube consists of a photocathode, a multiplication system, and an anode. The photocathode is crucial for the photoelectric conversion process, and its fabrication is the core technology in PMT production. Different alkali metals such as potassium, cesium, and sodium are activated with an antimony evaporation source in a vacuum device, undergoing a specific reaction to ultimately produce the photocathode.

[0003] Due to the structural characteristics of daradox photomultiplier tubes, the antimony evaporation source is usually made into a spherical shape (a spherical evaporation source is beneficial for forming a uniform coating inside the multiplier tube). The antimony sphere is connected to a metal lead wire, and the metal leads at both ends of the antimony evaporation source are usually welded and fixed to two different electrode pins. During the fabrication of the photocathode, current is applied to the electrodes to achieve thermal evaporation of the antimony evaporation source.

[0004] Among these factors, the size and quality of the antimony evaporation source are crucial for achieving consistent performance and process characteristics in photocathodes, such as sensitivity and uniformity. Traditional daradox photomultiplier tubes typically use antimony powder to melt into balls, which are then fused together with leads. This process is largely manual, and the manual melting process makes it difficult to precisely control the amount of antimony powder used. This results in antimony balls that are too large (typically exceeding 0.3 mm in diameter) and exhibit high dispersion, failing to meet the requirements of daradox photomultiplier tubes for extremely small evaporation sources. Consequently, this affects cathode uniformity and activation consistency.

[0005] In addition, the quantitative melting device and method for antimony bead evaporation source disclosed in CN119242932A improves the weight consistency and purity of antimony beads through a vacuum system and quantitative tooling. However, it uses high vacuum and argon protection, has a long vacuuming and cooling time, and the tooling is a fixed volume groove, which is not optimized for antimony balls with extremely small size (≤φ0.3mm), so it cannot achieve continuous automated production. Summary of the Invention

[0006] To address the technical problems existing in existing antimony evaporation sources, the first aspect of this invention proposes a technical solution: a device for preparing extremely small-sized leaded antimony spheres for a dipole-type photomultiplier tube evaporation source, comprising: The enclosure contains a relatively independent first space and a second space. An atmosphere conditioning system includes a first gas source for providing a first atmosphere gas to a first space and a second gas source for providing a second atmosphere gas to a second space; The lead wire transmission component includes a drive unit and a lead wire. The drive unit drives the lead wire to move horizontally in a stepping motion, passing through the first space and into the second space, where it stays for a predetermined time before exiting the second space and returning to the first space. A powder supply component is disposed within the second space and intermittently covers a predetermined amount of antimony powder around the lead wire; A power supply system, comprising a power source and a pair of electrodes; The controller is electrically connected to the atmosphere conditioning system, the lead wire drive component, and the powder supply component; The controller is used to coordinate the actions of the lead wire conduit components, power supply system, atmosphere conditioning system, and powder supply components, which are executed sequentially within one work cycle: - Pause process, pause process, control the power supply to apply current to the lead wire of the section through a pair of electrodes in a predetermined multi-stage sequence, so that the lead wire successively undergoes preheating, antimony powder adhesion, antimony powder melting and finally condensation into spheres. The powder supply component carries a predetermined amount of antimony powder to a specific section of the lead wire in the antimony powder adhesion stage, and carries the remaining antimony powder to separate from the lead wire before the antimony powder melts and finally condenses into spheres. - During the movement process, the conventional lead wire component drives the lead wire to move according to a predetermined step length, so that the formed antimony ball is moved out of the second space and the next section of lead wire to be processed is sent into the second space; The powder supply component includes a support platform, a powder hopper, and a powder supply drive mechanism. During the pause, the support platform with a predetermined size is driven by the powder supply drive mechanism to carry a predetermined amount of antimony powder from the powder hopper and move upward from the lead wire to a target distance from the lead wire, so that the antimony powder comes into contact with the lead wire. After the antimony powder adheres to the surface of the lead wire and before the molten ball, the powder supply drive mechanism drives the support platform back to the powder hopper.

[0007] Preferably, the box body forms a closed space, and an inner box body is also provided inside the box body. The box body is provided with an air inlet and an exhaust outlet. The air inlet, the closed space inside the box body and the exhaust outlet constitute a first space. The inner box body is provided with an air inlet pipe and an exhaust pipe extending to the outside of the inner box body. The air inlet pipe, the inner box body and the exhaust pipe constitute a second space. The inner housing is provided with two wire-passing holes for the lead wire to pass through. The lead wire enters the inner housing through the wire-passing hole on the first side and exits the inner housing through the wire-passing hole on the second side.

[0008] Preferably, the lead wire transmission component includes a first turntable, a second turntable, and a lead wire wound on the first turntable and the second turntable. A first guide wheel and a second guide wheel are respectively provided on both sides of the inner housing, and the cross-sections of the first guide wheel and the second guide wheel coincide with the axes of the two wire passage holes.

[0009] Preferably, the support platform includes a powder scoop, the powder scoop has a support surface, the support surface is an arc surface, and the antimony powder supported by the support surface forms a predetermined shape, the width of which gradually narrows and the length gradually increases from the bottom of the support surface upward.

[0010] Preferably, the diameter of the lead wire is 0.2 mm, the outer diameter of the molten ball on the surface of the lead wire is less than or equal to 0.3 mm, the diameter of the arc surface is 5 mm, and the area of ​​the arc surface is 5.5 mm². 2 During the pause process, the distance between the bottom of the arc surface and the lead wire on the carrier platform is L1, and the depth of the lead wire submerged in antimony powder is L2, where L1 = 0.9~1.1mm and L2 = 0.2~0.4mm.

[0011] Preferably, the powder scoop is configured to have inclined surfaces on both sides of the bearing surface, so that the width of the bearing surface gradually decreases from the bottom to the top.

[0012] Preferably, the support platform further includes a connecting arm and a support rod, the powder scoop is connected to the end of the support rod, and the powder supply drive mechanism is connected to the powder scoop through the connecting arm.

[0013] Preferably, the first atmospheric gas includes nitrogen, the second atmospheric gas includes 93% N2 and 7% H2 by volume, and the flow rate of the second atmospheric gas is 3~3.2 L / min.

[0014] Preferably, during one cycle of the lead wire completing the movement process and the pause process, the controller controls the state of the power supply so that the lead wire sequentially passes through four stages: preheating, melting, ball melting and residual heat. During the preheating phase, the lead wire is paused, and the power supply applies current to the lead wire according to the first parameter to make the lead wire heat up. After the preheating phase is completed, the powder supply component carries a predetermined amount of antimony powder and moves to the target position that contacts the lead wire. During the melting stage, the lead wire is in a paused process, and the power supply applies current to the lead wire according to the second parameter to keep the lead wire in a heat-preserving state. After the melting stage is completed, the powder supply component carries the remaining antimony powder and separates from the lead wire. During the ball-molding stage, the lead wire is in a paused process, and the power supply applies current to the lead wire according to the third parameter to make the lead wire continue to heat up; During the residual heat stage, the lead wire is in a paused process, and the power supply applies current to the lead wire according to the fourth parameter to cool the lead wire.

[0015] Preferably, the first parameter includes a current of 3.55A and a duration of 1.7s, the second parameter includes a current of 3.5A and a duration of 0.5s, the third parameter includes a current of 4A and a duration of 0.6s, and the fourth parameter includes a current of 0A and a duration of 5s.

[0016] Preferably, during the pause process: The controller is used to adjust the magnitude and duration of the current applied to the lead and the flow rate of the second atmospheric gas according to the size of the molten ball on the lead surface, so that the size of the molten ball on the lead surface conforms to the target size.

[0017] The second aspect of this invention proposes a technical solution: a process for preparing a tiny-sized antimony sphere with leads for a dipole photomultiplier tube evaporation source, using the aforementioned preparation equipment, and comprising the following steps: Step S1: Provide high-purity antimony blocks, crush, ball mill, and sieve to obtain antimony powder of a predetermined particle size, and vacuum bake the antimony powder to remove gas before loading it into the powder hopper of the powder supply component. Step S2: Install the lead wire onto the lead wire transmission component and pass it through the first space and the second space in sequence; introduce a first type of atmospheric gas into the first space and a second type of atmospheric gas into the second space through the atmosphere conditioning system; Step S3: Repeat the antimony ball melting cycle, with each cycle corresponding to one step length of the lead wire, including: Pause process: (a) Lead preheating: The power supply applies current to the lead according to the first parameter to make the lead in a heated state; (b) Melting and Separation: After the lead wire is preheated, the powder supply component carries a predetermined amount of antimony powder and moves to the target position that contacts the lead wire. The power supply system applies a current of the second parameter to the lead wire, causing the antimony powder to adhere to the surface of the lead wire and melt and shrink. After melting, the support platform carries the remaining antimony powder and separates it from the lead wire. (c) Molten ball: After the carrier platform is separated, the third stage current is applied to the lead wire through the power system, so that the adhering antimony powder melts and finally condenses to form an antimony ball; (d) Lead wire cooling: The power supply applies current to the lead wire according to the fourth parameter to cool the lead wire. Movement process: (e) Drive the lead wire to move by a predetermined step length, so that the formed antimony ball is moved out of the processing position, and move the next section of the lead wire to be processed to the processing position.

[0018] Preferably, in the ball-melting step of the pause process, the current applied to the lead wire sequentially passes through four stages: preheating, melting, ball-melting, and residual heat. Preheating stage: Apply a current of 3.55A for 1.7s to heat the lead wire to a dark red color; Melting stage: Apply a current of 3.5A for 0.5s to allow antimony powder to adhere to the lead surface; Molten ball stage: Apply a current of 4A for 0.6s to melt and condense the adhering antimony powder into spherical shapes; Residual heat stage: The current is cut off for 5 seconds, allowing the antimony ball to cool naturally under a protective atmosphere.

[0019] Compared with the prior art, the advantages of the present invention are as follows: This application, through the coordinated operation of lead-wire stepper drive, quantitative powder supply component and power system, can continuously execute the powder-ball-removal process, replacing the traditional manual or batch operation mode. This not only improves production efficiency, but also ensures a high degree of consistency in size, weight and shape of each antimony ball, achieving high consistency continuous production of extremely small antimony balls, and indirectly improving the performance uniformity and yield of photomultiplier tube products. In the preparation of the evaporation source, nitrogen gas is introduced into the outer chamber to form basic protection, and a hydrogen-containing mixed gas is introduced into the inner chamber. The hydrogen gas is used to actively reduce the trace oxides and water vapor that may exist in the melting process, thereby obtaining high-purity antimony balls with bright surfaces and no oxide layer under non-high vacuum conditions. Compared with simple high vacuum or inert gas protection, the anti-oxidation effect is more thorough, and the equipment cost and process complexity are lower.

[0020] The antimony ball melting process is designed with four stages: preheating, melting, ball melting, and residual heat. This allows for precise timing management of heat input and a smooth transition of antimony powder from adhesion and melting to forming. It avoids problems such as cracking, internal porosity, or irregular shape of the antimony balls caused by thermal shock. The resulting antimony balls have a dense structure and high mechanical strength, and can withstand vibration and thermal stress in subsequent processes and the operating environment, significantly extending the working life of the photomultiplier tube. Attached Figure Description

[0021] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may 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 equipment for preparing extremely small antimony balls with leads for a photomultiplier tube evaporation source, as shown in this invention. Figure 2This is a front view of the apparatus for preparing extremely small antimony spheres with leads for a photomultiplier tube evaporation source, as shown in this invention. Figure 3 This is a schematic diagram of the structure of the support platform shown in this invention; Figure 4 This is a schematic diagram of the bearing surface of the present invention, with antimony powder mounted below the lead wire; Figure 5 This is a schematic diagram of the bearing surface covered with antimony powder as shown in this invention; Figure 6 This is a schematic diagram showing how the lead wires of this invention cause the surrounding antimony powder to melt and eventually condense into spheres; Figure 7 This invention relates to a method for preparing a tiny leaded antimony ball for an evaporation source of a photomultiplier tube, as shown in an embodiment of the invention. Figure 8 This is a physical image of the antimony ball with leads shown in this invention. Detailed Implementation

[0022] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0023] {Example 1} Combination Figure 1 and Figure 2 As shown, the first aspect of the present invention proposes a technical solution: a device for preparing extremely small antimony balls with leads for a dynamo photomultiplier tube evaporation source, comprising a housing, an atmosphere conditioning system, a lead transmission component, a powder supply component, a power supply system, and a controller.

[0024] The box contains a relatively independent first space and a second space.

[0025] like Figure 1 and Figure 2 As shown, the box body is a closed space consisting of a bottom plate 12 and a transparent sealing plate 11. An inner box body 15 is also provided inside the box body. The inner box body 15 has a similar structure to the box body, including a bottom plate and a transparent sealing plate facing the transparent sealing plate.

[0026] By setting up a transparent plate, it is beneficial to observe the size of the prepared antimony spheres from the outside, and to feed back the observed size of the antimony spheres to the preparation process parameters to ensure that the final antimony spheres meet the size requirements.

[0027] Furthermore, the housing is provided with an air inlet 13 and an exhaust outlet 14, and the air inlet 13, the enclosed space inside the housing and the exhaust outlet 14 constitute a first space. The inner housing 15 is provided with an air inlet pipe 16 and an exhaust pipe 18 extending to the outside of the inner housing 15, and the air inlet pipe 16, the inner housing 15 and the exhaust pipe 18 constitute a second space.

[0028] Preferably, a buffer tank 17 is connected to the air inlet end of the air inlet pipe 16 to ensure a stable input flow rate of the second atmosphere gas, prevent antimony powder from oxidizing and deteriorating during heating, and reduce the impact of gas flow rate changes on the process of melting antimony powder into antimony balls.

[0029] The inner casing 15 is provided with two wire holes for the lead wire 21 to pass through.

[0030] Thus, the lead wire 21 can pass through the wire hole on the first side of the inner housing 15 into the inner housing 15, and then pass through the wire hole on the second side out of the inner housing 15.

[0031] Furthermore, the atmosphere conditioning system includes a first gas source for providing a first type of atmosphere gas to a first space and a second gas source for providing a second type of atmosphere gas to a second space.

[0032] Thus, the atmosphere conditioning system can provide a suitable atmosphere for the molten antimony powder balls during the preparation of the evaporation source, and at the same time provide an inert gas protective atmosphere for the lead 21.

[0033] In an optional embodiment, the first atmosphere gas includes nitrogen, and the second atmosphere gas includes 93% N2 and 7% H2 by volume.

[0034] Thus, the outer casing ensures a basic inert gas atmosphere, while the atmosphere inside the inner casing 15 is 93% N2 + 7% H2. The nitrogen in the inner casing prevents metal oxidation. Even within the nitrogen protective atmosphere, a small amount of oxygen or water vapor is still present. The antimony powder melting process is a high-temperature reaction, during which hydrogen reacts with oxides to form a bright surface, improving the appearance quality of the antimony balls.

[0035] In particular, it can prevent the surface of the antimony ball from cracking. It is important to understand that if the surface of the antimony ball cracks after the photomultiplier tube product is subjected to vibration and impact during transportation and use, a large amount of antimony slag will fall off. If the antimony slag falls into the metal electrodes or other conductive structures inside the photomultiplier tube, it will cause problems such as electrode short circuit, internal discharge, and arcing. By filling with protective gas, the oxidation, deterioration and cracking of antimony powder during the melting process can be prevented.

[0036] Furthermore, in an optional embodiment, the flow rate of the second atmospheric gas is 3~3.2 L / min.

[0037] In this way, the second atmosphere gas can form a stable and uniform airflow curtain in the inner chamber 15, effectively isolating and blowing away trace amounts of oxygen and water vapor that may seep in from the wire holes, ensuring the purity of the molten ball environment, and also providing enough hydrogen to achieve the reduction effect. At the same time, it will not interfere with the stable loading of antimony powder or cause deformation of the molten antimony ball due to excessive flow rate, thus ensuring the stability of the process and the forming quality of the antimony ball.

[0038] Combination Figure 1 and Figure 2 As shown, the lead wire transmission component includes a drive unit and a lead wire 21. The drive unit drives the lead wire 21 to move horizontally in a stepping motion, passing through the first space and entering the second space, where it stays for a predetermined time before exiting the second space and returning to the first space.

[0039] In this way, the lead wire moves through the two spaces in a step-by-step manner, which is conducive to continuous production. Through the cycle of moving-pausing-moving, the removal of the formed antimony ball and the processing of a new section of lead wire can be seamlessly connected.

[0040] In an optional embodiment, the lead wire drive component includes a first turntable 22, a second turntable 25, and a lead wire 21 wound on the first turntable 22 and the second turntable 25. A first guide wheel 23 and a second guide wheel 24 are respectively provided on both sides of the inner housing 15, and the cross-sections of the first guide wheel 23 and the second guide wheel 24 coincide with the axes of the two wire holes.

[0041] Specifically, one of the first turntable 22 and the second turntable 25 is responsible for winding the lead wire 21, and the other is responsible for winding the lead wire 21 after melting the antimony ball. Figure 1 and Figure 2 In the first turntable 22, a lead wire 21 is wound around it, and a second turntable 25 is wound with the lead wire 21 containing an antimony ball. The lead wire 21 between the first guide wheel 23 and the second guide wheel 24 moves from the first guide wheel 23 to the second guide wheel 24. The second turntable 25 can be used as a drive wheel.

[0042] Furthermore, the powder supply component is located in the second space, namely the inner box 15, and intermittently covers a predetermined amount of antimony powder around the lead wire 21.

[0043] Combination Figure 1 as well as Figure 3 As shown, the powder supply component includes a support platform 31, a powder hopper 32, and a powder supply drive mechanism 33. The powder hopper 32 is used to store a certain amount of antimony powder 34, and the powder supply drive mechanism 33 is used to drive the support platform 31 and the powder hopper 32 to move closer to each other, so that the support platform 31 can take a certain amount of antimony powder 34 from the powder hopper 32.

[0044] Optionally, the support platform 31 also includes a connecting arm 311 and a support rod 312, with the powder scoop 313 connected to the end of the support rod 312, and the powder supply drive mechanism 33 connected to the powder scoop 313 via the connecting arm 311.

[0045] In this way, the powder supply component can achieve an integrated automatic execution function of quantitative powder taking, precise powder delivery and safe withdrawal. The powder quantity is initially controlled by the predetermined size of the support platform 31, and the spatial position is precisely moved by the drive mechanism to ensure the consistency of the powder depth of the lead wire 21. Finally, it automatically withdraws after melting the ball to avoid interference with the finished product, which is conducive to the continuous and quantitative preparation of extremely small antimony balls.

[0046] The power supply system includes a power supply and a pair of electrodes 41. The controller is electrically connected to the atmosphere conditioning system, the lead wire drive component, and the powder supply component.

[0047] The electrode 41 is arranged on the moving path of the lead 21, and the contact state with the lead 21 can be controlled by clamping / releasing to control whether current is applied between the two electrodes 21 and the lead 21.

[0048] Furthermore, the controller coordinates the actions of the lead-conducting components, power supply system, atmosphere conditioning system, and powder supply components, executing them sequentially within a work cycle: -During the pause process, the control power supply applies current to the lead wire 21 of the section through a pair of electrodes 41 in a predetermined multi-stage sequence, so that the lead wire 21 undergoes preheating, antimony powder adhesion, antimony powder melting and finally condensation into spheres in sequence. During the antimony powder adhesion stage, the powder supply component carries a predetermined amount of antimony powder 34 and moves to a specific section of the lead wire 21. Before the antimony powder melts and finally condenses into spheres, the remaining antimony powder 34 is separated from the lead wire 21. - During the movement process, the conventional lead wire component drives the lead wire 21 to move according to a predetermined step length, so that the formed antimony ball is moved out of the second space and the next section of lead wire 21 to be processed is sent into the second space.

[0049] As mentioned above, the controller coordinates various components to break down the complex melting process into standardized unit operations that are executed in an orderly alternation and cycle in time and space. This allows the formation process of each antimony ball to be parameterized and standardized, eliminating the uncertainty of human operation. At the same time, the cyclic operation mode makes large-scale, continuous production possible, thereby improving efficiency while greatly ensuring the extremely high consistency of product size, purity and performance.

[0050] Furthermore, during the pause, the carrier platform 31 with a predetermined size is driven by the powder supply drive mechanism 33 to carry a predetermined amount of antimony powder 34 from the powder hopper 32 and move upward from below the lead wire 21 to a target distance from the lead wire 21, so that the antimony powder 34 comes into contact with the lead wire 21. Before the surface of the lead wire 21 begins to melt, the powder supply drive mechanism 33 drives the carrier platform 31 back to the powder hopper 32.

[0051] In this way, the antimony powder 34 moves upward from below the lead wire 21 and comes into contact with the lead wire 21, which ensures that the antimony powder can be stably and controllably wrapped around the lead wire. In particular, the antimony powder 34 naturally gathers and adheres to the lead wire under the action of gravity, avoiding the powder from scattering. In addition, since the distance between the powder and the lead wire 21 is the same each time, that is, the depth of the lead wire 21 into the antimony powder 34 is stably controlled, which is the key to controlling the consistent amount of powder each time.

[0052] In a preferred embodiment, the powder supply drive mechanism 33 carries the antimony powder 34 around the lead wire 21 and immediately descends and separates it before the melting ball is formed (because the melting ball temperature is high, if it is not separated in time, the surrounding antimony powder 34 will be further melted, resulting in an increase in the size of the heat-shrinking antimony ball). This can prevent the high-temperature antimony ball or lead wire 21 from sticking to more antimony powder 34, so as to ensure that the size of the antimony ball meets the requirements.

[0053] In a preferred embodiment, combined with Figure 3 As shown, the support platform 31 includes a powder scoop 313, which has a support surface 313a. The support surface 313a is an arc surface. The antimony powder 34 supported by the support surface 313a forms a predetermined shape. From the bottom of the support surface 313a upwards, its width gradually narrows and its length gradually increases.

[0054] Furthermore, the powder scoop 313 is configured to have inclined surfaces 313b on both sides of the bearing surface 313a, so that the width of the bearing surface 313a gradually decreases from the bottom to the top.

[0055] like Figure 3 As shown, it should be understood that the arc-shaped structure of the bearing surface 313a, combined with the inclined surfaces 313b on both sides, has the structural feature of forming a naturally powder-gathering groove that is thick in the middle and thin on both sides.

[0056] In this application, the powder is supplied to the molten ball by moving the bearing surface 313a upwards towards the lead wire 21. This specific arc surface area and volume limit the maximum theoretical value of powder taken each time, which is the basis for achieving the predetermined amount of powder supply. At the same time, the arc shape makes the antimony powder form a cohesive powder pile, which is not easy to scatter during the movement. Furthermore, when the lead wire 21 is immersed in the antimony powder 34, the inclined structure on both sides allows the antimony powder 34 to wrap and concentrate more smoothly towards the central area of ​​the lead wire 21, which helps to form a round and symmetrical sphere after melting and avoids the formation of irregular spheres.

[0057] In a specific embodiment, the diameter of lead 21 is 0.2 mm, the outer diameter of the molten ball on the surface of lead 21 is less than or equal to 0.3 mm, the diameter of the arc surface is 5 mm, and the area of ​​the arc surface is 5.5 mm². 2 During the pause process, the distance between the support platform 31 and the bottom of the arc surface and the lead wire 21 is L1, and the lead wire 21 is submerged in antimony powder to a depth of L2, where L1 = 0.9mm~1.1mm and L2 = 0.2mm~0.4mm.

[0058] Lead 21 can be selected as a nickel wire or a platinum-coated molybdenum wire.

[0059] Furthermore, in the above embodiment, during one cycle of the lead 21 completing the moving process and the pause process, the controller controls the state of the power supply so that the lead 21 sequentially goes through four stages: preheating, melting, ball melting and residual heat. During the preheating stage, lead 21 is in a paused process, and the power supply applies current to lead 21 according to the first parameter, so that lead 21 is in a heated state. During the melting stage, lead wire 21 is paused. After the preheating stage, the powder supply component, which carries a predetermined amount of antimony powder 34, moves to the target position that contacts lead wire 21. The power supply applies current to lead wire 21 according to the second parameter, so that lead wire 21 is kept in a heat-preserving state. After the melting stage, the powder supply component, which carries the remaining antimony powder 34, separates from lead wire 21. During the ball-molding stage, lead 21 is in a paused process, and the power supply applies current to lead 21 according to the third parameter, so that lead 21 continues to heat up; During the residual heat stage, lead 21 is in a paused process, and the power supply applies current to lead 21 according to the fourth parameter, so that lead 21 is in a cooling state.

[0060] By setting up four stages—preheating, melting, ball melting, and residual heat—precise management of thermal energy during the ball melting process can be achieved.

[0061] Specifically, during the preheating stage, the leads are preheated to the operating temperature (close to 500 degrees Celsius) to provide a uniform thermal field for subsequent instantaneous powder coating, avoiding uneven powder coating caused by cold leads.

[0062] During the melting stage: a current slightly lower than the preheating current is used to soften the antimony powder and make it firmly adhere to the lead wire, rather than melting and dripping it immediately, thus achieving reliable powder transfer.

[0063] In the spherical melting stage: increasing the current causes the adhering antimony powder to melt rapidly, and under the action of surface tension, it condenses into a spherical shape.

[0064] During the residual heat stage: cutting off the current and slowly cooling can effectively release the internal thermal stress of the antimony ball, reduce the formation of microcracks, and improve the mechanical strength and environmental reliability of the antimony ball.

[0065] Preferably, the first parameter includes a current of 3.55A and a duration of 1.7s, the second parameter includes a current of 3.5A and a duration of 0.5s, the third parameter includes a current of 4A and a duration of 0.6s, and the fourth parameter includes a current of 0A and a duration of 5s.

[0066] This ensures that the lead wire can quickly reach and precisely maintain the target temperature range, guaranteeing that the antimony powder fully melts into spheres while minimizing excessive evaporation and oxidation of antimony. This results in the stable production of extremely small antimony spheres with precise dimensions, bright surfaces, and dense structures, achieving very high consistency and yield. Figure 8 As shown.

[0067] In an optional embodiment, during the pause process: The controller is used to adjust the magnitude and duration of the current applied to the lead 21 and the flow rate of the second atmospheric gas according to the size of the molten ball on the surface of the lead 21, so that the size of the molten ball on the surface of the lead 21 conforms to the target size.

[0068] The priority order for adjusting the current magnitude, duration, and flow rate of the second atmospheric gas is: current value > duration > gas flow rate.

[0069] This allows for online fine-tuning of the process based on the dimensions of the molten antimony spheres. When operators detect fluctuations in product dimensions, they can use the above adjustment method to fine-tune the process and quickly restore process stability.

[0070] {Example 2} Combination Figures 4 to 6 As shown, the second aspect of the present invention proposes a technical solution, a process for preparing a tiny antimony ball with leads for a photomultiplier tube evaporation source, using the above-mentioned preparation equipment, including the following steps: Step S1: Provide high-purity antimony blocks, crush, ball mill, and sieve to obtain antimony powder 34 with a predetermined particle size, and after vacuum baking and degassing the antimony powder 34, load it into the powder hopper 32 of the powder supply component. Optionally, the antimony powder is screened using 200-mesh and 250-mesh sieves and mixed in a 1:1 ratio.

[0071] Optionally, the vacuum degree of vacuum baking and degassing is better than 1×10⁻ 5 Pa, baking temperature is 300℃, duration is 2 hours.

[0072] Step S2: Install lead wire 21 onto lead wire transmission component and pass it through first space and second space in sequence; introduce first atmospheric gas into first space and second atmospheric gas into second space through atmosphere conditioning system; Optionally, the first atmospheric gas is nitrogen, and the second atmospheric gas is a mixture of 93% N2 and 7% H2 by volume, and the flow rate of the second atmospheric gas is controlled to be 3~3.2 L / min.

[0073] Step S3: Repeat the antimony ball melting cycle, with each cycle corresponding to one step length of lead 21, including: Pause process: (a) Preheating of lead 21: The power supply applies current to lead 21 according to the first parameter (current 3.55A, duration 1.7s) to make lead 21 heat up. (b) Melting and Separation: After the lead wire 21 is preheated, the powder supply component carries a predetermined amount of antimony powder 34 and moves to the target position that contacts the lead wire 21. The power supply system applies a current with the second parameter (current 3.5A, duration 0.5s) to the lead wire 21, causing the antimony powder 34 to adhere to the surface of the lead wire 21 and melt and shrink. After the melting stage is completed, the support platform 31 carries the remaining antimony powder 34 and separates from the lead wire 21. (c) Molten ball: After the support platform 31 is separated, the third stage current (current 4A, duration 0.6s) is applied to the lead wire 21 through the power system, so that the adsorbed antimony powder melts and finally condenses to form an antimony ball; (d) Cooling of lead 21: The power supply applies current to lead 21 according to the fourth parameter, so that lead 21 is in a cooling state; Movement process: (e) Drive the lead wire 21 to move by a predetermined step length, so that the formed antimony ball is moved out of the processing position, and move the next section of lead wire 21 to be processed to the processing position.

[0074] Optionally, the predetermined step length is 40mm, and the step length is determined according to the length of lead 21.

[0075] Optionally, the current applied to lead 21 passes through four stages in sequence: preheating, melting, molten ball formation, and residual heat. Preheating stage: Apply a current of 3.55A for 1.7s to heat lead 21 to a dark red color; Melting stage: After this stage, the powder scoop 313 containing antimony powder 34 is moved to the position of contact with the lead wire 21, so that the lead wire initially adheres to the powder. A current of 3.5A is applied for 0.5s, so that the antimony powder 34 continues to adhere to the surface of the lead wire 21. When this stage is over, the powder scoop 313 carrying the remaining antimony powder 34 separates from the lead wire 21 and returns to the powder hopper. Molten ball stage: Apply current of 4A for 0.6s to melt and condense the adhering antimony powder 34 into spheres; Residual heat stage: The current is cut off for 5 seconds, allowing the antimony ball to cool naturally under a protective atmosphere.

[0076] Furthermore, the above preparation method also includes step S4, quality feedback and adjustment: The size and apparent quality of the formed antimony spheres were tested. If the size of the antimony ball does not meet the target of ≤φ0.3mm, the process parameters are corrected by adjusting the current value by ±0.02A and / or adjusting the current duration by ±0.1s.

[0077] Specifically, the magnitude and duration of the current applied to the lead 21 and the flow rate of the second atmospheric gas are adjusted according to the size of the molten ball on the surface of the lead 21 so that the size of the molten ball on the surface of the lead 21 conforms to the target size.

[0078] The priority order for adjusting the current magnitude, duration, and flow rate of the second atmospheric gas is: current value > duration > gas flow rate.

[0079] This allows for online fine-tuning of the process based on the dimensions of the molten antimony spheres. When operators detect fluctuations in product dimensions, they can use the above adjustment method to fine-tune the process and quickly restore process stability.

[0080] Combination Figures 4 to 6 as well as Figure 7 As shown in the specific embodiment, the preparation method of using an antimony ball no larger than 0.3 mm on the surface of a 0.2 mm lead as an evaporation source is as follows: Preparation of S1-antimony powder: Antimony blocks with a purity of 6N were selected, crushed, and then ball-milled for 60-80 minutes. The antimony powder was then screened using 250-mesh and 200-mesh sieves and mixed in a 1:1 ratio. The antimony powder was then subjected to vacuum high-temperature baking to remove gas, with a vacuum degree better than 1×10⁻⁶. -5 Baking temperature 300℃ for 2 hours, then storing in a drying cabinet.

[0081] S2 - Lead wire installation: Wind all φ0.2mm nickel wire / platinum-coated molybdenum wire leads onto the first turntable 22, pull out one end of the lead wire, pass it through the two guide wheels of the lead wire transmission mechanism in sequence, and finally wind it onto the second turntable 25.

[0082] S3 - Add antimony powder and introduce gas: Install the powder scoop 313 on the powder supply drive mechanism 33, put the antimony powder prepared in step S1 into the powder hopper 32, introduce the second atmosphere gas (gas A) into the inner box 15, adjust the valve to control the flow rate of the second atmosphere gas to 3L / min~3.2L / min, and introduce the first atmosphere gas (gas B) into the box.

[0083] S4 - Feeding to the lead wire area: The powder supply drive mechanism 33 drives the powder scoop 313 to scoop antimony powder 34 to the position below the lead wire 21, and the antimony powder 34 does not contact the lead wire 21.

[0084] The S5-ball-forming process consists of four stages: preheating stage, melting stage, ball-forming stage, and residual heat stage.

[0085] S6 - Lead preheating: After clamping lead 21 with the clamping clamp (electrode), preheat lead 21 by energizing it. The preheating current is 3.55A and the preheating time is 1.7s.

[0086] S7 - Antimony Powder Melting: After preheating, the powder supply drive mechanism 33 immediately moves the powder scoop 313 containing antimony powder 34 to the position of the lead wire 21, ensuring that the antimony powder 34 is in contact with the lead wire 21, and the depth of the lead wire 21 submerging the antimony powder is within the range of 0.2mm to 0.4mm. The metal wire is energized with a melting current of 3.5A, and the melting time is 0.5s, resulting in the lead wire being coated with an appropriate amount of antimony powder.

[0087] S8-Antimony Powder Melting Ball: The powder supply drive mechanism 33 moves the powder spoon 313 downward to the initial position and continues to energize the lead wire 21. The melting ball current is 4A and the melting ball time is 0.6s.

[0088] S9-Antimony Ball Heat Dissipation: Release the fixing clamp (electrode not in contact with lead wire), adjust the current to 0A, and control the residual heat time of the antimony ball to 5s.

[0089] S10 - Antimony ball movement: Drive the first turntable 22 and the second turntable 25 to move the melted antimony ball and lead wire 40mm to the right.

[0090] S11 - Size and Quality Adjustment: Confirm the size (≤φ0.3mm) and apparent quality of the antimony ball from the above steps, and make corrections by appropriately adjusting the current value and time in steps S6-S9 according to the units of ±0.02A and ±0.1s.

[0091] S12 - Repeat the operation: Follow steps S4-S11 to complete the next round of melting process.

[0092] 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 device for preparing a small size evaporation source antimony ball with a lead wire for a dynode type photomultiplier tube, characterized in that, The application relates to a device for manufacturing a soldering tin ball, which comprises the following parts: a box, in which a first space and a second space are arranged independently; an atmosphere adjusting system, which comprises a first gas source for providing a first atmosphere gas to the first space and a second gas source for providing a second atmosphere gas to the second space; a lead driving part, which comprises a driving unit and a lead (21), the driving unit drives the lead (21) to move in a step-by-step mode along a horizontal direction through the first space into the second space, stays in the second space for a predetermined time length, and then moves out of the second space back into the first space; a powder supplying part, which is arranged in the second space and intermittently covers a predetermined amount of tin powder around the lead (21); a power supply system, which comprises a power supply and a pair of electrodes (41); a controller, which is electrically connected with the atmosphere adjusting system, the lead driving part and the powder supplying part; wherein the controller is used for coordinating the actions of the lead driving part, the power supply system, the atmosphere adjusting system and the powder supplying part, and sequentially executing the following processes in a working cycle: a pause process, the power supply controls the pair of electrodes (41) to apply current to the lead (21) in the section according to a predetermined multi-stage time sequence, so that the lead (21) sequentially experiences preheating, tin powder adhesion, tin powder melting and finally polycondensation into a ball, the powder supplying part carries a predetermined amount of tin powder (34) to move to a specific section of the lead (21) in the tin powder adhesion stage, and separates the remaining tin powder (34) from the lead (21) before the tin powder melts and finally polycondenses into a ball; a moving process, the lead driving part drives the lead (21) to move according to a predetermined step length, so that the formed tin ball moves out of the second space, and the next section of the lead (21) to be processed is sent into the second space; wherein the powder supplying part comprises a carrying table (31), a powder bin (32) and a powder supplying driving mechanism (33), in the pause process, the carrying table (31) with a predetermined size is driven by the powder supplying driving mechanism (33) to carry a predetermined amount of tin powder (34) from the powder bin (32) to move upwards from the lower part of the lead (21) to a target distance from the lead (21), and make the tin powder (34) contact with the lead (21), when the lead (21) surface adheres to the tin powder, the powder supplying driving mechanism (33) drives the carrying table (31) to return to the powder bin (32) again.

2. The preparation equipment for evaporating source electrode small size antimony balls with lead wire of photomultiplier tube of puncher type according to claim 1, characterized in that, The box constitutes a closed space, an inner box (15) is further arranged in the box, an air inlet (13) and an air outlet (14) are arranged on the box, the first space is formed by the air inlet (13), the closed space in the box and the air outlet (14), the inner box (15) is provided with an air inlet pipeline (16) and an air outlet pipeline (18) which extend to the outside of the inner box (15), and the second space is formed by the air inlet pipeline (16), the inner box (15) and the air outlet pipeline (18); two lead passing holes are arranged on the inner box (15) for the lead (21) to pass through, the lead (21) passes into the inner box (15) through the lead passing hole on the first side of the inner box (15), and then passes out of the inner box (15) through the lead passing hole on the second side.

3. The apparatus for preparing small size lead-wired antimony balls of an evaporation source electrode of a dynode-type photomultiplier tube according to claim 2, characterized by, The lead transmission component comprises a first rotating disc (22), a second rotating disc (25) and a lead wire (21) arranged around the first rotating disc (22) and the second rotating disc (25), and a first guide wheel (23) and a second guide wheel (24) are arranged on both sides of the inner box (15), and the cross section of the first guide wheel (23) and the second guide wheel (24) coincides with the axis of the two wire passing holes.

4. The apparatus for preparing small size lead-wired antimony spheres of an evaporation source of a dynode-type photomultiplier tube according to claim 1, wherein The carrying table (31) comprises a powder spoon (313), and the powder spoon (313) is provided with a carrying surface (313a), the carrying surface (313a) is a curved surface, and the powder spoon (313) is configured to be provided with an inclined surface (313b) on both sides of the carrying surface (313a), so that the carrying surface (313a) gradually decreases in width from the bottom upwards, and the antimony powder (34) carried by the carrying surface (313a) forms a predetermined shape, and gradually narrows in width and gradually lengthens upwards from the bottom of the carrying surface (313a).

5. The apparatus for preparing small size lead-wired antimony balls of an evaporation source electrode of a dynode-type photomultiplier tube according to claim 4, characterized by, The diameter of the lead wire (21) is 0.2mm, the outer diameter of the melt ball on the surface of the lead wire (21) is less than or equal to 0.3mm, the diameter of the arc surface is 5mm, and the area of the arc surface is 5.5mm 2 During the pause process, the distance between the bottom of the arc surface and the lead wire (21) on the bearing table (31) is L1, and the depth of the lead wire (21) in the antimony powder is L2, wherein L1=0.9~1.1mm, and L2=0.2~0.4mm.

6. The apparatus for preparing small size lead-wired antimony balls of an evaporation source for a dynode-type photomultiplier tube according to claim 1, wherein The first kind of atmosphere gas comprises nitrogen, and the second kind of atmosphere gas comprises 93% nitrogen and 7% hydrogen in volume ratio, and the gas flow of the second kind of atmosphere gas is 3-3.2 L / min.

7. The apparatus for preparing small size lead-wired antimony balls of an evaporation source for a dynode-type photomultiplier tube according to claim 1, wherein In a cycle of the moving process and the pause process of the lead wire (21), the controller controls the state of the power supply, so that the lead wire (21) sequentially passes through the preheating, melting, molten ball and residual heat four stages; In the preheating stage, the lead wire (21) is in the pause process, the power supply applies current to the lead wire (21) according to the first parameter, so that the lead wire (21) is in the heating state, and after the preheating stage ends, the powder supply component carrying a predetermined amount of antimony powder (34) moves to the target position in contact with the lead wire (21); In the melting stage, the lead wire (21) is in the pause process, the power supply applies current to the lead wire (21) according to the second parameter, so that the lead wire (21) is in the holding state, and after the melting stage ends, the powder supply component carrying the remaining antimony powder (34) is separated from the lead wire (21); In the molten ball stage, the lead wire (21) is in the pause process, the power supply applies current to the lead wire (21) according to the third parameter, so that the lead wire (21) continues to heat up; In the residual heat stage, the lead wire (21) is in the pause process, the power supply applies current to the lead wire (21) according to the fourth parameter, so that the lead wire (21) is in the cooling state.

8. The apparatus for preparing small size lead-wired antimony spheres from an evaporation source of a photomultiplier tube of the pin-type according to claim 1, wherein, The first parameter comprises a current of 3.55 A and a duration of 1.7 s, the second parameter comprises a current of 3.5 A and a duration of 0.5 s, the third parameter comprises a current of 4 A and a duration of 0.6 s, and the fourth parameter comprises a current of 0 A and a duration of 5 s.

9. The apparatus for producing small size lead-wired antimony spheres for evaporation sources of photomultiplier tubes of the dynode type according to any one of claims 1-8, characterized in that, In the pause process: The controller is used for adjusting the current applied to the lead wire (21), the duration and the flow of the second kind of atmosphere gas according to the size of the molten ball on the surface of the lead wire (21), so that the size of the molten ball on the surface of the lead wire (21) meets the target size.

10. A process for preparing small size lead-wired antimony spheres from an evaporation source of dynode type photomultiplier tubes, characterized in that, The preparation device of any one of claims 1-9 comprises the following steps: Step S1, providing high-purity antimony block, crushing, ball milling, and screening to obtain antimony powder (34) with a predetermined particle size, and vacuum baking and degassing the antimony powder (34) before loading into the powder bin (32) of the powder feeding component; Step S2, installing the lead wire (21) on the lead wire driving component and sequentially passing through the first space and the second space; introducing the first atmosphere gas into the first space and the second atmosphere gas into the second space through the atmosphere adjusting system; Step S3, cyclically performing the antimony ball melting cycle, each cycle corresponding to a step length of the lead wire (21), including: pause process: (a) lead wire (21) preheating: the power supply applies current to the lead wire (21) according to the first parameter, so that the lead wire (21) is in a heating state; (b) melting and separation: after the lead wire (21) preheating is completed, the powder feeding component carrying a predetermined amount of antimony powder (34) moves to the target position in contact with the lead wire (21), and the power supply system applies current to the lead wire (21) according to the second parameter, so that the lead wire (21) surface adheres to the antimony powder (34) and shrinks, and after the melting is completed, the carrying table (31) carries the remaining antimony powder (34) and separates from the lead wire (21); (c) melt ball: after the carrying table (31) is separated, the power supply system applies current to the lead wire (21) according to the third parameter, so that the adhered antimony powder is melted and finally shrinks to form an antimony ball; (d) lead wire (21) cooling: the power supply applies current to the lead wire (21) according to the fourth parameter, so that the lead wire (21) is in a cooling state; moving process: (e) driving the lead wire (21) to move a predetermined step length, so that the formed antimony ball moves out of the processing position, and the next section of the lead wire (21) to be processed is moved to the processing position.

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