Vacuum tube batch coating device for particle accelerator and use method thereof

Abstract

The present invention discloses a vacuum tube batch coating device for a particle accelerator and a method for using the same. The coating device comprises an upper cavity, a lower cavity, a vacuum tube to be coated, an upper connecting mechanism, a weight mechanism, a solenoid electromagnet and a magnet mounting base. A plurality of vacuum tubes to be coated are arranged between the upper cavity and the lower cavity. The upper and lower ends of each vacuum tube to be coated are connected to the upper and lower cavities respectively through the upper connecting mechanism and the weight mechanism. A solenoid electromagnet is arranged on the periphery of the plurality of vacuum tubes to be coated, and the bottom of the solenoid electromagnet is arranged in the magnet mounting base. The method for using the device is to first install each vacuum tube to be coated one by one, and perform leak detection and vacuuming to form an integrated multi-coating channel mechanism, and then hoist the vacuum tube in the solenoid electromagnet by a crane to form an integrated vacuum tube batch coating device, and then perform leak detection and vacuuming as a whole. The present invention can realize batch coating of a plurality of vacuum tubes, and realize efficient and stable NEG coating treatment of vacuum tubes.

Description

Technical Field

[0001] The present invention relates to the technical field of particle accelerators, and in particular to a vacuum tube batch coating device for particle accelerators and a use method thereof. Background Art

[0002] The vacuum system is the basic engineering of the particle accelerator. Only when the beam runs in a vacuum environment can it maintain a sufficient lifespan and be continuously accumulated and accelerated to reach the designed energy and flux. Since the interaction between the accelerated particles and the residual gas in the vacuum will cause the beam lifetime to decrease and cause beam instability and detector background, the main goal of the vacuum system design is to obtain and maintain a reasonable vacuum degree to ensure the stable operation of the beam. When the high-energy particles in the storage ring move in the vacuum chamber, they will be lost due to the interaction with the residual gas such as Coulomb scattering, nuclear scattering and Bremsstrahlung. Therefore, in order to maintain a long beam lifetime, the highest requirement for the vacuum degree is usually required to reach 10 -7 ~10 - 8 Pa.

[0003] One of the difficulties in designing a storage ring vacuum system is how to achieve the dynamic vacuum requirement when a beam is present. In a storage ring vacuum system, the reason for the pressure rise is not only the thermal degassing of vacuum materials, but also the photon desorption caused by the synchrotron radiation hitting the inner surface of the vacuum tube. In a high-current electron storage ring, electrons generate synchrotron radiation along the tangential direction when they are bending. High-energy photons hitting the vacuum tube and the photon absorber will cause the temperature and pressure to rise. The gas load caused by synchrotron radiation is 1 to 2 orders of magnitude larger than the general material thermal degassing load. In order to reduce the gas load, the cleanliness of the inner wall of the vacuum tube must be improved to reduce the degassing caused by the photoelectron bombardment wall. At the same time, a special vacuum structure design is adopted, and a distributed or centralized pumping method is used to improve the pumping efficiency of the vacuum system to meet the vacuum requirements of the beam life.

[0004] The acquisition and maintenance of ultra-high vacuum is mainly achieved through discretely distributed vacuum pumps (such as sputtering ion pumps, titanium sublimation pumps, non-evaporable getter pumps, etc.). There is a certain longitudinal gradient in the pressure distribution inside the vacuum tube, that is, the vacuum degree near the vacuum pump is better, while the vacuum degree farther away from the vacuum pump is poorer. The engineering scale of particle accelerators is usually large, but due to the limitation of actual installation space, the number of vacuum pumps needs to be minimized, that is, the spacing between vacuum pumps is often large; in addition, the vacuum chamber used in the accelerator is usually a slender pipe with small flow conductance, so its pressure gradient is often high, which will affect the life and stability of the beam in severe cases. Therefore, NEG film (i.e. zirconium-vanadium-titanium alloy film) is usually plated on the inner wall of the vacuum tube. Experiments have shown that the vacuum degree of the vacuum tube with NEG film plated on the inner wall is 1 to 2 orders of magnitude better than that of the vacuum tube without coating.

[0005] NEG film is plated on the inner wall of the vacuum tube, and the residual gas in the vacuum chamber is adsorbed by the NEG film to achieve distributed exhaust, so that the vacuum chamber is changed from a gas outgassing source to a "vacuum pump" with exhaust capability. In addition, NEG film can also reduce the outgassing rate of the inner surface of the vacuum chamber; reduce the secondary electron yield (SEY) on the inner surface of the vacuum chamber, etc. However, NEG film cannot extract inert gases and CH4, so ion pumps are generally installed at both ends of the plated vacuum chamber to assist exhaust in order to achieve a high vacuum. It can be seen that whether a high-quality NEG film can be obtained is a key factor in whether a slender vacuum tube can achieve a good vacuum effect.

[0006] The NEG coating system uses a reasonable coating method and builds a corresponding experimental platform to coat the inner wall of the vacuum tube with a high-quality air-absorbing film, thereby obtaining a good vacuum distribution. The vacuum tube is generally coated by magnetron sputtering. The magnetic field is generated by a circular electromagnet. The cathode target wire is located in the center of the vacuum chamber. The cathode wire is energized. In an argon or krypton atmosphere, the vacuum chamber is coated with a NEG film of about 1 micron by magnetron sputtering. The traditional coating method is an experimental behavior and can only be coated one by one. However, in the practice of particle accelerator engineering, a fourth-generation light source accelerator storage ring vacuum system usually contains more than 1,000 copper vacuum chambers with a length of less than 1.5 meters. According to the needs of the project, more than 1,000 vacuum chambers need to be coated in 6 months or less. Therefore, how to coat in batches, efficiently and with high quality is one of the key difficulties of current NEG coating. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a vacuum tube batch coating device for a particle accelerator, which can simultaneously perform batch coating on the inner walls of multiple vacuum tubes to achieve efficient and stable vacuum tube NEG coating processing.

[0008] Another object of the present invention is to provide a method for using the vacuum tube batch coating device for the above-mentioned particle accelerator.

[0009] The technical solution of the present invention is: a vacuum tube batch coating device for a particle accelerator, comprising an upper cavity, a lower cavity, vacuum tubes to be coated, an upper connecting mechanism, a weight mechanism, a solenoid electromagnet and a magnet mounting base, a plurality of vacuum tubes to be coated are arranged between the upper cavity and the lower cavity, the upper end of each vacuum tube to be coated is connected to the upper cavity through the upper connecting mechanism, the lower end of each vacuum tube to be coated is connected to the lower cavity through the weight mechanism, a solenoid electromagnet is arranged on the periphery of the plurality of vacuum tubes to be coated, and the bottom of the solenoid electromagnet is arranged in the magnet mounting base. Among them, the upper and lower ends of each vacuum tube to be coated are respectively installed and connected with the upper cavity and the lower cavity through the upper connecting mechanism and the heavy hammer mechanism, so that each vacuum tube to be coated can form an independent channel, which is convenient for leak detection and preliminary vacuuming of each vacuum tube to be coated separately. The upper and lower cavities are respectively connected to the gas supply system and the vacuuming system, which is convenient for leak detection and vacuuming of the entire vacuum tube batch coating device, and coating of multiple vacuum tubes to be coated at the same time. In addition to being used to connect the vacuum tube to be coated and the lower cavity, the heavy hammer mechanism can also ensure that the cathode target wire in the vacuum tube to be coated is always located at the center of the vacuum tube to be coated, preventing the cathode target wire from deviating from the center of the vacuum tube to be coated due to softening or deformation during the coating process.

[0010] An upper support frame is provided below the upper cavity, and a lower support frame is provided below the lower cavity, and a central profile is connected between the upper support frame and the lower support frame; multiple vacuum tubes to be coated are distributed along the periphery of the upper support frame and the lower support frame, and each vacuum tube to be coated is arranged parallel to the central profile; a magnet support frame is also provided below the upper cavity, and the top of the solenoid electromagnet support frame is connected to the magnet support frame. The upper support frame, the lower support frame and the central profile form an auxiliary support structure, which can effectively improve the stability of multiple vacuum tubes to be coated after installation and during coating.

[0011] The central profile is also provided with a number of middle auxiliary support plates, and the outer periphery of each middle auxiliary support plate is provided with a guide wheel. When the vacuum tube batch coating device is installed, each guide wheel contacts the inner wall of the solenoid electromagnet. When the multi-coating channel mechanism formed after the vacuum tubes to be coated are installed is hoisted into the solenoid electromagnet, the setting of the middle auxiliary support plate and the guide wheel can, on the one hand, play a guiding role to ensure the stability of the hoisting process, and on the other hand, the guide wheel contacts the inner wall of the solenoid magnet, which is conducive to quickly and smoothly installing the multi-coating channel mechanism into the solenoid electromagnet and plays a centering role.

[0012] The central profile is a square support tube, the upper end of the central profile is fixedly connected to the upper support frame, the lower end of the central profile is fixedly connected to the lower support frame, and a plurality of central auxiliary support plates are distributed on the periphery of the middle part of the central profile. The main body of each central auxiliary support plate is square, and the four corners of the central auxiliary support plate extend outward to form a guide wheel support part, and a guide wheel is arranged at the end of the guide wheel support part; the vacuum tube to be coated is located between two adjacent guide wheel support parts.

[0013] The upper connecting mechanism includes an upper bellows, an electrode fixing head, an upper fixed cavity and an upper sample mounting frame which are arranged in sequence from top to bottom. The top of the upper bellows is connected to the upper cavity, and the bottom of the upper sample mounting frame is connected to the vacuum tube to be coated. The inner cavity of the upper cavity is connected to the inner cavities of the upper bellows, the electrode fixing head, the upper fixed cavity and the upper sample mounting frame in sequence. An electrode is provided on one side of the electrode fixing head, and a cathode target wire is connected to one end of the electrode. The cathode target wire passes through the inner cavities of the electrode fixing head, the upper fixed cavity and the upper sample mounting frame and then extends into the inner cavity of the vacuum tube to be coated.

[0014] In the electrode fixing head, a ceramic shielding tube is also provided on the periphery of the cathode target wire; and a thin film gauge is also provided on the outer side of the electrode fixing head.

[0015] Among them, the electrode adopts CF16 vacuum electrode, one end of which is connected to the cathode target wire by setting an electrode head. The part of the electrode head located in the inner cavity of the electrode fixing head (i.e., in the vacuum cavity) is completely shielded by a ceramic shielding tube to prevent internal discharge of the electrode. The cathode target wire and the electrode head are fixed by a top screw or a thread (this installation method is a conventional installation method), and the cathode target wire is ensured to be in the center of the vacuum tube to be coated.

[0016] The weight mechanism comprises a lower bellows, a weight installation part, a lower fixed cavity and a lower sample mounting frame which are arranged in sequence from bottom to top, a weight is arranged in the weight installation part, a target wire fixing head is arranged at the connection between the lower fixed cavity and the weight installation part, the lower end of the target wire fixing head is fixedly connected to the weight, an end ceramic plate is arranged at the lower end of the weight, the end ceramic plate and the weight are locked and fixed by ceramic screws, the bottom of the lower bellows is connected to the lower cavity, the top of the lower sample mounting frame is connected to the vacuum tube to be coated, the inner cavity of the lower cavity is connected to the inner cavities of the lower bellows, the weight installation part, the lower fixed cavity and the lower sample mounting frame in sequence, and the cathode target wire in the vacuum tube to be coated passes through the inner cavity of the lower sample mounting frame and the lower fixed cavity and is fixedly mounted on the target wire fixing head.

[0017] In the target wire fixing head, a ceramic shielding tube is also provided at the periphery of the cathode target wire; in the weight installation part, an outer ceramic tube is also provided at the periphery of the weight; and a film gauge is also provided at the outer side of the weight installation part.

[0018] Among them, the weight is located at the center of the weight installation part, and an outer ceramic tube is arranged to insulate it from the inner cavity (i.e., the vacuum chamber) of the weight installation part. The lower end of the cathode target wire and the target wire fixing head are fixed by a top wire (this installation method is a conventional installation method). The outer ceramic tube and the end ceramic plate at the lower end of the weight are tightly matched to prevent the weight from discharging.

[0019] The top of the upper cavity and the bottom of the lower cavity are respectively provided with ion pumps, the upper cavity is also provided with an air inlet flange, and the lower cavity is also provided with an air extraction port. The air inlet flange is connected to an external air supply system, and the air extraction port is connected to an external molecular pump system for air extraction. The ion pumps on the upper and lower cavities can effectively ensure the vacuum degree in each vacuum tube to be coated.

[0020] The method for using the vacuum tube batch coating device for the particle accelerator of the present invention comprises the following steps:

[0021] (1) Each vacuum tube to be coated is installed one by one between the upper cavity and the lower cavity. The upper end of the vacuum tube to be coated is installed on the upper cavity through an upper connecting mechanism, and the lower end of the vacuum tube to be coated is installed on the lower cavity through a heavy hammer mechanism. An independent channel is formed in each vacuum tube to be coated. After installation, a leak test is performed first. After the leak test is completed, the vacuum tube to be coated is evacuated, and then vacuum-packaged and stored to form an integrated multi-coating channel mechanism;

[0022] (2) The multi-coating channel mechanism obtained in step (1) is lifted by a crane and installed in a solenoid electromagnet to form an integrated vacuum tube batch coating device, and the upper end of the vacuum tube batch coating device is connected to the air supply system, and the lower end is connected to the molecular pump system. Under a vacuum state, the vacuum tube batch coating device is leak-checked and evacuated as a whole, and then used for coating after completion.

[0023] Among them, when each vacuum tube to be coated is coated, the coating principle is the same as the NEG coating principle of a traditional single vacuum tube, that is: the coating method of the NEG film is DC magnetron sputtering coating, and its basic principle is to use a magnetic field to change the direction of electron movement, bind and extend the movement trajectory of electrons, thereby increasing the probability of electron ionization of the working gas and effectively utilizing the energy of electrons. Therefore, the sputtering of the target material caused by the bombardment of the target material by positive ions in the abnormal glow discharge that forms a high-density plasma is more effective. At the same time, the electrons bound by the orthogonal electromagnetic field can only be deposited on the substrate (i.e., the inner wall of the vacuum tube to be coated) when their energy is about to be exhausted. Magnetron sputtering has the mechanism of "low temperature" and "high speed". By controlling parameters such as the magnetic field and the discharge current, high-quality films with good adhesion and controllable quality can be plated. NEG coating system is generally composed of vacuum tube to be coated, cathode target wire, solenoid electromagnet and power supply, turbomolecular pump unit, vacuum gauge, residual gas analyzer, discharge power supply, gas flow controller and cooling device. The cathode target wire is composed of Ti, Zr, V alloy wire and fixed in the center of the vacuum tube to be coated. The coil of the solenoid electromagnet is axially sleeved outside the vacuum tube to form an orthogonal electromagnetic field with the cathode voltage to provide gas glow discharge conditions. High-purity discharge gas Kr is filled into the vacuum tube to be coated through the flow controller. The film is coated on the vacuum tube and then pumped away with a molecular pump unit. The discharge gas Kr is ionized under the action of the electromagnetic field. The Kr ions hit the cathode target wire and cause the getter material Ti-Zr-V to be sputtered. The sputtered material hits the inner wall of the vacuum tube to be coated to form a getter film. By adjusting the cathode voltage, the magnetic field of the solenoid electromagnet and the pressure of the Kr gas, the deposition rate of the getter film can be changed and the performance and quality of the film can be improved. After the vacuum tube to be coated is coated, the pumping speed, limit vacuum and activation life tests must be carried out to verify the reliability of the getter film.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The vacuum tube batch coating device for particle accelerator and the method for using the device can realize batch coating of the inner wall of multiple vacuum tubes at the same time, and realize efficient and stable NEG coating of vacuum tubes. In the coating device, multiple vacuum tubes to be coated with independent channels are arranged between the upper and lower cavities, and the upper and lower ends of each vacuum tube to be coated are respectively installed and fixed by independent upper connecting mechanisms (i.e., electrode fixing mechanisms) and heavy hammer mechanisms. The structure is stable and the NEG coating efficiency is high, which can greatly save the time required for vacuum tube coating, thereby reducing the engineering construction cost of the particle accelerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall structure of the vacuum tube batch coating device.

[0027] Figure 2 for Figure 1 AA direction section view.

[0028] Figure 3 for Figure 1 B direction view.

[0029] Figure 4 for Figure 3 CC direction cross-sectional view.

[0030] Figure 5 This is a schematic diagram of the structure of the vacuum tube batch coating device after removing the solenoid electromagnet and the magnet mounting base.

[0031] Figure 6 for Figure 5 D direction view.

[0032] Figure 7 for Figure 5 E direction view.

[0033] Figure 8 for Figure 7 FF direction cross-sectional view.

[0034] Fig. 9 for Figure 7 GG direction cross-sectional view.

[0035] Fig.10 This is a schematic diagram of a single vacuum tube to be coated and its installation structure.

[0036] Fig.11 for Fig.10 H direction view.

[0037] Fig.12 for Fig.10 Sectional view in direction II.

[0038] Fig.13 for Fig.12 Partial view of J.

[0039] Fig.14 for Fig.12 K partial views.

[0040] In the above figures, the components indicated by the reference numerals are as follows: 1 is an upper cavity, 2 is a lower cavity, 3 is a vacuum tube to be coated, 4 is an upper connecting mechanism, 5 is a heavy hammer mechanism, 6 is a solenoid electromagnet, 7 is a magnet mounting base, 8 is an upper support frame, 9 is a lower support frame, 10 is a central profile, 11 is a magnet support frame, 12 is a middle auxiliary support plate, 13 is a guide wheel, 14 is an ion pump, 15 is an air inlet flange, and 16 is an air extraction port;

[0041] 4-1 is the upper bellows, 4-2 is the electrode fixing head, 4-3 is the upper fixing cavity, 4-4 is the upper sample mounting frame, 4-5 is the electrode, 4-6 is the cathode target wire, 4-7 is the ceramic shielding tube, 4-8 is the film gauge, and 4-9 is the electrode head;

[0042] 5-1 is the lower bellows, 5-2 is the weight installation part, 5-3 is the lower fixed cavity, 5-4 is the lower sample mounting frame, 5-5 is the weight, 5-6 is the target wire fixing head, 5-7 is the end ceramic plate, 5-8 is the ceramic screw, and 5-9 is the outer ceramic tube. DETAILED DESCRIPTION

[0043] The present invention will be further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0044] Example

[0045] This embodiment provides a vacuum tube batch coating device for a particle accelerator and a method for using the same.

[0046] like Figure 1 , Figure 2 , Figures 5 to 8 As shown, the vacuum tube batch coating device includes an upper cavity 1, a lower cavity 2, a vacuum tube to be coated 3, an upper connecting mechanism 4, a weight mechanism 5, a solenoid electromagnet 6 and a magnet mounting base 7. A plurality of vacuum tubes to be coated are arranged between the upper cavity and the lower cavity. The upper end of each vacuum tube to be coated is connected to the upper cavity through the upper connecting mechanism, and the lower end of each vacuum tube to be coated is connected to the lower cavity through the weight mechanism. A solenoid electromagnet is arranged on the periphery of the plurality of vacuum tubes to be coated, and the bottom of the solenoid electromagnet is arranged in the magnet mounting base. The upper and lower ends of each vacuum tube to be coated are respectively installed and connected with the upper cavity and the lower cavity through the upper connecting mechanism and the weight mechanism, so that each vacuum tube to be coated can form an independent channel, which is convenient for leak detection and preliminary vacuuming of each vacuum tube to be coated separately. The upper and lower cavities are respectively connected to the gas supply system and the vacuuming system, which is convenient for leak detection and vacuuming of the entire vacuum tube batch coating device, and coating of a plurality of vacuum tubes to be coated at the same time. In addition to being used to connect the vacuum tube to be coated and the lower cavity, the weight mechanism can also ensure that the cathode target wire in the vacuum tube to be coated is always located at the center of the vacuum tube to be coated, thereby preventing the cathode target wire from deviating from the center of the vacuum tube to be coated due to softening or deformation during the coating process.

[0047] like Figure 5 or Figure 8 , Fig. 9As shown, an upper support frame 8 is provided under the upper cavity, a lower support frame 9 is provided under the lower cavity, and a central profile 10 is connected between the upper support frame and the lower support frame; a plurality of vacuum tubes to be coated are distributed along the periphery of the upper support frame and the lower support frame, and each vacuum tube to be coated is arranged parallel to the central profile; a magnet support frame 11 is also provided under the upper cavity, and the top of the solenoid electromagnet support frame is connected to the magnet support frame. The upper support frame, the lower support frame and the central profile form an auxiliary support structure, which can effectively improve the stability of the plurality of vacuum tubes to be coated after installation and during the coating process. A number of middle auxiliary support plates 12 are also distributed on the central profile, and a guide wheel 13 is installed on the periphery of each middle auxiliary support plate. When the vacuum tube batch coating device is installed, each guide wheel contacts the inner wall of the solenoid electromagnet (such as Figure 4 As shown). When the multi-coating channel mechanism formed after the vacuum tubes to be coated are installed is hoisted into the solenoid electromagnet, the setting of the middle auxiliary support plate and the guide wheel can play a guiding role on the one hand to ensure the stability of the lifting process. On the other hand, the guide wheel is in contact with the inner wall of the solenoid magnet, which is conducive to the rapid and smooth installation of the multi-coating channel mechanism into the solenoid electromagnet and plays a centering role. The central profile is a square support tube, the upper end of the central profile is fixedly connected to the upper support frame, the lower end of the central profile is fixedly connected to the lower support frame, and a plurality of central auxiliary support plates are distributed on the periphery of the middle of the central profile. The main body of each central auxiliary support plate is square, and the four corners of the central auxiliary support plate extend outward to form a guide wheel support portion, and a guide wheel is set at the end of the guide wheel support portion; the vacuum tube to be coated is located between two adjacent guide wheel support portions.

[0048] Among them, a single vacuum tube to be coated and its installation structure are as follows Figure 10 to Figure 14 shown.

[0049] like Fig.13As shown, the upper connection mechanism includes an upper bellows 4-1, an electrode fixing head 4-2, an upper fixed cavity 4-3 and an upper sample mounting frame 4-4 which are arranged in sequence from top to bottom. The top of the upper bellows is connected to the upper cavity, the bottom of the upper sample mounting frame is connected to the vacuum tube to be coated, and the inner cavity of the upper cavity is connected to the inner cavities of the upper bellows, the electrode fixing head, the upper fixed cavity and the upper sample mounting frame in sequence. An electrode 4-5 is provided on one side of the electrode fixing head, and a cathode target wire 4-6 is connected to one end of the electrode. The cathode target wire passes through the inner cavities of the electrode fixing head, the upper fixed cavity and the upper sample mounting frame and then extends into the inner cavity of the vacuum tube to be coated. In the electrode fixing head, a ceramic shielding tube 4-7 is also provided on the periphery of the cathode target wire; and a thin film gauge 4-8 is also provided on the outer side of the electrode fixing head. Among them, the electrode adopts CF16 vacuum electrode, one end of which is connected to the cathode target wire by setting an electrode head 4-9. The part of the electrode head located in the inner cavity of the electrode fixing head (i.e., in the vacuum cavity) is completely shielded by a ceramic shielding tube to prevent internal discharge of the electrode. The cathode target wire and the electrode head are fixed by a top screw or a thread (this installation method is a conventional installation method), and the cathode target wire is ensured to be in the center of the vacuum tube to be coated.

[0050] like Fig.14 As shown, the weight mechanism includes a lower bellows 5-1, a weight mounting part 5-2, a lower fixed cavity 5-3 and a lower sample mounting frame 5-4 which are arranged in sequence from bottom to top, a weight 5-5 is arranged in the weight mounting part, a target wire fixing head 5-6 is arranged at the connection between the lower fixed cavity and the weight mounting part, the lower end of the target wire fixing head is fixedly connected to the weight, an end ceramic plate 5-7 is arranged at the lower end of the weight, the end ceramic plate and the weight are locked and fixed by a ceramic screw 5-8, the bottom of the lower bellows is connected to the lower cavity, the top of the lower sample mounting frame is connected to the vacuum tube to be coated, the inner cavity of the lower cavity is connected to the inner cavities of the lower bellows, the weight mounting part, the lower fixed cavity and the lower sample mounting frame in sequence, and the cathode target wire 4-6 in the vacuum tube to be coated passes through the inner cavities of the lower sample mounting frame and the lower fixed cavity and is fixedly mounted on the target wire fixing head. In the target wire fixing head, a ceramic shielding tube is also provided on the periphery of the cathode target wire; in the weight hammer installation part, an outer ceramic tube 5-9 is also provided on the periphery of the weight hammer; and a thin film gauge is also provided on the outer side of the weight hammer installation part. The weight hammer is located at the center of the weight hammer installation part, and is insulated from the inner cavity (i.e., the vacuum chamber) of the weight hammer installation part by providing an outer ceramic tube. The lower end of the cathode target wire is fixedly installed with the target wire fixing head by a top wire (this installation method is a conventional installation method), and the outer ceramic tube is tightly matched with the end ceramic plate at the lower end of the weight hammer to prevent the weight hammer from discharging.

[0051] like Figures 5 to 8As shown, an ion pump 14 is provided at the top of the upper cavity and the bottom of the lower cavity respectively, an air inlet flange 15 is provided on the upper cavity, and an air extraction port 16 is provided on the lower cavity. The air inlet flange is connected to an external air supply system, and the air extraction port is connected to an external molecular pump system for air extraction. The arrangement of the ion pumps on the upper and lower cavities can effectively ensure the vacuum degree in each vacuum tube to be coated.

[0052] The method for using the above-mentioned vacuum tube batch coating device for particle accelerator comprises the following steps:

[0053] (1) Each vacuum tube to be coated is installed one by one between the upper cavity and the lower cavity. The upper end of the vacuum tube to be coated is installed on the upper cavity through an upper connecting mechanism, and the lower end of the vacuum tube to be coated is installed on the lower cavity through a heavy hammer mechanism. An independent channel is formed in each vacuum tube to be coated. After installation, a leak test is performed first. After the leak test is completed, the vacuum tube to be coated is evacuated, and then vacuum-packaged and stored to form an integrated multi-coating channel mechanism;

[0054] (2) The multi-coating channel mechanism obtained in step (1) is lifted by a crane and installed in a solenoid electromagnet to form an integrated vacuum tube batch coating device, and the upper end of the vacuum tube batch coating device is connected to the air supply system, and the lower end is connected to the molecular pump system. Under a vacuum state, the vacuum tube batch coating device is leak-checked and evacuated as a whole, and then used for coating after completion.

[0055] Among them, when each vacuum tube to be coated is coated, the coating principle is the same as the NEG coating principle of a traditional single vacuum tube, that is: the coating method of the NEG film is DC magnetron sputtering coating, and its basic principle is to use a magnetic field to change the direction of electron movement, bind and extend the movement trajectory of electrons, thereby increasing the probability of electron ionization of the working gas and effectively utilizing the energy of electrons. Therefore, the sputtering of the target material caused by the bombardment of the target material by positive ions in the abnormal glow discharge that forms a high-density plasma is more effective. At the same time, the electrons bound by the orthogonal electromagnetic field can only be deposited on the substrate (i.e., the inner wall of the vacuum tube to be coated) when their energy is about to be exhausted. Magnetron sputtering has the mechanism of "low temperature" and "high speed". By controlling parameters such as the magnetic field and the discharge current, high-quality films with good adhesion and controllable quality can be plated. NEG coating system is generally composed of vacuum tube to be coated, cathode target wire, solenoid electromagnet and power supply, turbomolecular pump unit, vacuum gauge, residual gas analyzer, discharge power supply, gas flow controller and cooling device. The cathode target wire is composed of Ti, Zr, V alloy wire and fixed in the center of the vacuum tube to be coated. The coil of the solenoid electromagnet is axially sleeved outside the vacuum tube to form an orthogonal electromagnetic field with the cathode voltage to provide gas glow discharge conditions. High-purity discharge gas Kr is filled into the vacuum tube to be coated through the flow controller. The film is coated on the vacuum tube and then pumped away with a molecular pump unit. The discharge gas Kr is ionized under the action of the electromagnetic field. The Kr ions hit the cathode target wire and cause the getter material Ti-Zr-V to be sputtered. The sputtered material hits the inner wall of the vacuum tube to be coated to form a getter film. By adjusting the cathode voltage, the magnetic field of the solenoid electromagnet and the pressure of the Kr gas, the deposition rate of the getter film can be changed and the performance and quality of the film can be improved. After the vacuum tube to be coated is coated, the pumping speed, limit vacuum and activation life tests must be carried out to verify the reliability of the getter film.

[0056] As described above, the present invention can be better implemented. The above embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention; that is, all equivalent changes and modifications made according to the content of the present invention are covered by the scope of protection required by the claims of the present invention.

Claims

1. A vacuum tube batch coating device for a particle accelerator, characterized in that: It includes an upper cavity, a lower cavity, a vacuum tube to be coated, an upper connecting mechanism, a weight mechanism, a solenoid electromagnet and a magnet mounting base. A plurality of vacuum tubes to be coated are arranged between the upper cavity and the lower cavity. The upper end of each vacuum tube to be coated is connected to the upper cavity through the upper connecting mechanism, and the lower end of each vacuum tube to be coated is connected to the lower cavity through the weight mechanism. A solenoid electromagnet is arranged on the periphery of the plurality of vacuum tubes to be coated, and the bottom of the solenoid electromagnet is arranged in the magnet mounting base. An upper support frame is provided below the upper cavity, and a lower support frame is provided below the lower cavity, and a central profile is connected between the upper support frame and the lower support frame; a plurality of vacuum tubes to be coated are distributed along the periphery of the upper support frame and the lower support frame, and each vacuum tube to be coated is arranged parallel to the central profile; a magnet support frame is also provided below the upper cavity, and the top of the solenoid electromagnet support frame is connected to the magnet support frame; A plurality of middle auxiliary support plates are also distributed on the central profile, and a guide wheel is installed on the periphery of each middle auxiliary support plate. When the vacuum tube batch coating device is installed, each guide wheel contacts the inner wall of the solenoid electromagnet; The central profile is a square support pipe, the upper end of the central profile is fixedly connected to the upper support frame, the lower end of the central profile is fixedly connected to the lower support frame, and a plurality of central auxiliary support plates are distributed on the periphery of the central part of the central profile, the main body of each central auxiliary support plate is square, and the four corners of the central auxiliary support plate extend outward to form a guide wheel support portion, and a guide wheel is arranged at the end of the guide wheel support portion; The vacuum tube to be coated is located between two adjacent guide wheel support parts.

2. The vacuum tube batch coating device for a particle accelerator according to claim 1, characterized in that: The upper connecting mechanism includes an upper bellows, an electrode fixing head, an upper fixed cavity and an upper sample mounting frame which are arranged in sequence from top to bottom. The top of the upper bellows is connected to the upper cavity, and the bottom of the upper sample mounting frame is connected to the vacuum tube to be coated. The inner cavity of the upper cavity is connected to the inner cavities of the upper bellows, the electrode fixing head, the upper fixed cavity and the upper sample mounting frame in sequence. An electrode is provided on one side of the electrode fixing head, and a cathode target wire is connected to one end of the electrode. The cathode target wire passes through the inner cavities of the electrode fixing head, the upper fixed cavity and the upper sample mounting frame and then extends into the inner cavity of the vacuum tube to be coated.

3. The vacuum tube batch coating device for a particle accelerator according to claim 2, characterized in that: In the electrode fixing head, a ceramic shielding tube is also provided on the periphery of the cathode target wire; and a thin film gauge is also provided on the outer side of the electrode fixing head.

4. The vacuum tube batch coating device for a particle accelerator according to claim 2, characterized in that: The weight mechanism comprises a lower bellows, a weight installation part, a lower fixed cavity and a lower sample mounting frame which are arranged in sequence from bottom to top, a weight is arranged in the weight installation part, a target wire fixing head is arranged at the connection between the lower fixed cavity and the weight installation part, the lower end of the target wire fixing head is fixedly connected to the weight, an end ceramic plate is arranged at the lower end of the weight, the end ceramic plate and the weight are locked and fixed by ceramic screws, the bottom of the lower bellows is connected to the lower cavity, the top of the lower sample mounting frame is connected to the vacuum tube to be coated, the inner cavity of the lower cavity is connected to the inner cavities of the lower bellows, the weight installation part, the lower fixed cavity and the lower sample mounting frame in sequence, and the cathode target wire in the vacuum tube to be coated passes through the inner cavity of the lower sample mounting frame and the lower fixed cavity and is fixedly mounted on the target wire fixing head.

5. The vacuum tube batch coating device for a particle accelerator according to claim 4, characterized in that: In the target wire fixing head, a ceramic shielding tube is also provided at the periphery of the cathode target wire; in the weight installation part, an outer ceramic tube is also provided at the periphery of the weight; and a film gauge is also provided at the outer side of the weight installation part.

6. The vacuum tube batch coating device for a particle accelerator according to claim 1, characterized in that: The top of the upper cavity and the bottom of the lower cavity are respectively provided with ion pumps, the upper cavity is also provided with an air inlet flange, and the lower cavity is also provided with an air extraction port.

7. A method for using the vacuum tube batch coating device for a particle accelerator according to any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Each vacuum tube to be coated is installed one by one between the upper cavity and the lower cavity. The upper end of the vacuum tube to be coated is installed on the upper cavity through an upper connecting mechanism, and the lower end of the vacuum tube to be coated is installed on the lower cavity through a heavy hammer mechanism. An independent channel is formed in each vacuum tube to be coated. After installation, a leak test is performed first. After the leak test is completed, the vacuum tube to be coated is evacuated, and then vacuum-packaged and stored to form an integrated multi-coating channel mechanism; (2) The multi-coating channel mechanism obtained in step (1) is lifted by a crane and installed in a solenoid electromagnet to form an integrated vacuum tube batch coating device, and the upper end of the vacuum tube batch coating device is connected to the air supply system, and the lower end is connected to the molecular pump system. Under a vacuum state, the vacuum tube batch coating device is leak-checked and evacuated as a whole, and then used for coating after completion.

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