Method for assembling a dual-energy electron gun for an accelerator tube

Abstract

This invention discloses an accelerated assembly method for a dual-energy electron gun. The method utilizes a sealing fixture to seal the gun housing to obtain a ceramic gun housing sealing assembly; an argon arc welding fixture is used to perform argon arc welding on the ceramic gun housing sealing assembly and the anode transition assembly to obtain a welded electron gun housing assembly; a cathode component welding fixture is used to position and weld the cathode assembly and the connecting sleeve to obtain a cathode component; and a cathode positioning fixture is used to weld the cathode component to the welded electron gun housing assembly to obtain the dual-energy electron gun. By utilizing various fixtures, the assembly process of the dual-energy electron gun is standardized into a welding assembly flow, breaking down the overall welding process into the welding of individual small components. This facilitates step-by-step welding and reduces personnel training costs. Individual small components are inspected and qualified before proceeding to the next process, improving the yield rate and reducing the operational difficulty of the precision requirements of each step. The method also prevents changes in the installation dimensions of parts due to stress during the welding process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of accelerators, and particularly relates to a double-energy electron gun assembling method for an acceleration tube. BACKGROUND

[0002] An electron linear accelerator is mainly composed of an electron gun, a cavity chain and a target. The electron gun generates an electron beam with certain energy, shape and current density. Then, the alternating electric field formed by the cavity chain accelerates the electrons along the beam path, and finally, the accelerated electrons hit the target to generate corresponding high-energy X-rays. In the electron linear accelerator tube, the electron gun is the core component of the accelerator, and the parameters such as the electron injection range, the beam waist radius and the emission current of the electron gun have specific requirements. The electron gun is mainly composed of a cathode, an anode, a focusing electrode and a ceramic gun shell. When working, the filament heats the cathode to a specific working temperature, and the required high voltage is applied to the focusing electrode and the anode. A specific acceleration electric field is formed near the surface of the cathode, which can accelerate the electrons emitted by the cathode to the required initial velocity of the electron beam and converge into a specific electron beam shape.

[0003] The assembly size precision of the cathode, the focusing electrode and the anode of the electron gun directly affects the distribution of the acceleration electric field. Therefore, the assembly of the electron gun is a critical link in the production process of the acceleration tube.

[0004] The cathode assembly of the electron gun has a small size and high relative size requirements (the tolerance size needs to be controlled within 0.03 mm). In the assembly process, it is difficult to ensure that the assembly is in place by hand assembly, and welding-related processes are also used. The thermal stress of the welding position is large, and the size deviation after welding is large. Finally, it will lead to assembly failure, repeated rework, low production yield, and even cause the cathode assembly to be scrapped, resulting in great economic losses. Therefore, reducing the assembly difficulty of the electron gun and improving the assembly precision can bring high economic benefits to the enterprise and greatly promote the development of the acceleration tube. SUMMARY

[0005] To overcome the aforementioned shortcomings, the inventors of this invention, through long-term exploration, experimentation, and continuous reform and innovation, have proposed an accelerated assembly method for dual-energy electron guns. This method utilizes various tooling fixtures to standardize the assembly process of the dual-energy electron gun, breaking down the overall welding process into the welding of individual components. This standardized production process, with designated personnel performing specific welding procedures, significantly reduces personnel training costs and facilitates step-by-step welding. Individual components are inspected and approved before proceeding to the next process, improving yield. The use of tooling fixtures reduces the operational difficulty of achieving high-precision welding at each step. Forced locking within the tooling ensures that stress during welding does not cause changes in the component's installation dimensions, making welding of the product simple.

[0006] To achieve the above objectives, the technical solution adopted by this invention is: to provide a method for assembling an accelerated tube dual-energy electron gun. The assembly steps are as follows:

[0007] S1, Gun casing sealing: The sealing plate position is defined by the sealing tool, thereby sealing the gun casing of the electron gun to obtain a ceramic gun casing sealing assembly.

[0008] S2, Anode transition assembly sealing: The anode transition ring and the argon arc weld edge are sealed together, and then the anode transition ring is installed on the anode mounting plate using the mating stop at the lower end of the anode transition ring for positioning, thus obtaining the anode transition assembly;

[0009] S3, Gun casing TIG welding: 3.1) Assemble the anode transition assembly onto the TIG welding fixture and tighten it with the bottom locking screw;

[0010] 3.2) Position the ceramic gun shell sealing assembly and the anode transition assembly by fitting the argon arc welding fixture into the inner hole of the intermediate sealing plate. Then, use the mounting block and the top locking screw at the upper end of the argon arc welding fixture to lock the anode transition assembly from the upper end of the gun shell. Then perform argon arc welding to obtain the welded electron gun shell assembly.

[0011] S4, Cathode heat shield cylinder welding: The upper and lower ends of the inner wall in contact with the cathode and the heat shield cylinder are fixed by spot welding to form a cathode assembly;

[0012] S5, Cathode component welding: S5.1 Fix the cathode assembly using the cathode component welding fixture; S5.2 Lock the connecting sleeve onto the cathode component welding fixture using screws, use a dial indicator to test the parallelism between the connecting sleeve and the cathode assembly, and after the test is qualified, laser weld the cathode component to obtain the cathode component, then remove the cathode component welding fixture, measure the distance between the cathode component and the preset value, and wipe the laser weld point;

[0013] S6, electron gun assembly: S6.1, install the negative control part into the cathode positioning tool, then detect the parallelism of the gun shell surface, and confirm that it is installed in place; S6.2, install the negative control part installed in the cathode positioning tool on the upper end of the welded electron gun shell assembly for locking, at this time the welded electron gun shell assembly is placed upside down and located in the gun shell, and is pressed tightly by using the weight of the cathode positioning tool itself; S6.3, after checking that the cooperation is in place, laser welding is performed, and the installed size and cold resistance are re-measured.

[0014] S7, argon arc welding: install the electron gun cover plate, and perform argon arc welding on the whole electron gun.

[0015] According to the double-energy electron gun assembly method for the accelerating tube, in the further preferred technical solution of the step S1, the sealing tool includes a center positioning column a and an edge limiting fence, the center positioning column a is a three-section cylindrical structure, the lower section is a disc for receiving the gun shell, the middle section is a cylinder with a diameter matched with the diameter of the middle hole of the lower sealing plate, and the upper section is a cylinder with a diameter matched with the diameter of the middle sealing plate; the upper section is matched with the middle hole of the assembly block a to realize the concentricity of the center positioning column a and the gun shell; the assembly block a is provided with a step matched with the size of the upper end of the gun shell to realize positioning; the edge limiting fence is attached to the middle part of the gun shell, and the lower end of the edge limiting fence is attached to the upper surface of the disc to serve as a reference surface; a limiting groove is arranged on the inner side of the edge limiting fence, and the height and depth of the limiting groove are used to control the height of each sealing plate and / or the coaxiality with the gun shell.

[0016] According to the double-energy electron gun assembly method for the accelerating tube, in the further preferred technical solution, the diameter of the inner circle of the upper sealing plate is greater than the diameter of the upper section, and the upper sealing plate completely controls the height and the coaxiality with the gun shell by using the edge limiting fence; the hole in the middle of the middle sealing plate is embedded with the upper section of the center positioning column a to control the coaxiality with the gun shell, and the height is controlled by using the edge limiting fence; the height and the coaxiality with the gun shell are controlled by using the edge limiting fence, and the coaxiality with the gun shell is further adjusted by embedding the hole in the lower sealing plate with the center positioning column a.

[0017] According to the double-energy electron gun assembly method for the accelerating tube, in the further preferred technical solution of the step S3, the argon arc welding tool includes a center positioning column b, an assembly block b, a bottom locking screw and a top locking screw, the center positioning column b is a two-section cylindrical structure, the lower end is a mounting seat, and the upper end is a positioning section; a step is arranged on the mounting seat to cooperate with the internal step of the anode transition ring to realize installation and positioning; the anode transition ring is fixed on the center positioning column b by the bottom locking screw; the assembly block b is used to install the top locking screw from the upper end of the gun shell; the top locking screw is connected to the mounting hole of the center positioning column b on the upper end through the assembly block b.

[0018] According to the present invention, a further preferred technical solution of the assembly method of a dual-energy electron gun for an accelerator tube is as follows: In step S5, the cathode component welding fixture includes a base a and a positioning pin. The base a is provided with a boss for engaging with the inner groove on the cathode assembly to fix and position the cathode assembly. The lower end of the connecting sleeve is fitted onto the outer edge of the cathode assembly for positioning. The base a is provided with a mounting hole for screws to fix the connecting sleeve on the base a. A pin hole is provided at the center of the boss on the base a. The positioning pin passes through the central hole of the focusing electrode to install and position the focusing electrode on the base a.

[0019] According to the present invention, a further preferred technical solution of the assembly method of a dual-energy electron gun for an accelerator tube is as follows: In step S6, the cathode positioning fixture includes a base b, mounting screws, and positioning screws. The cathode control component is installed on the base b through the process hole on the connecting sleeve using mounting screws. The base b is provided with a step for positioning in conjunction with the anode transition ring. The base b is installed on the anode transition ring by positioning screws, and the cathode positioning fixture is inverted and pressed by the weight of the base b itself.

[0020] A further preferred embodiment of the method for assembling a dual-energy electron gun for an accelerator tube according to the present invention is as follows: in the laser steps S5.2 and S6.4, the laser solder joints must be wiped with a silk cloth and the spattered solder slag must be cleaned.

[0021] A further preferred technical solution of the assembly method of a dual-energy electron gun for an accelerator tube according to the present invention is that the parallelism accuracy requirement in steps S5.2 and S6.3 is ±0.01mm-±0.04mm.

[0022] A further preferred technical solution of the dual-energy electron gun assembly method for accelerating tubes according to the present invention is: in step S6.3, the retest mounting frame size standard is kept consistent, and the cold resistance requirement is less than the threshold.

[0023] A further preferred embodiment of the method for assembling a dual-energy electron gun for an accelerator tube according to the present invention is as follows: process holes are provided in the anode transition ring and the connecting sleeve for bolt installation and positioning with the argon arc welding fixture, the cathode control component welding fixture, and the cathode positioning fixture.

[0024] Compared with the prior art, the technical solution of the present invention has the following advantages / benefits:

[0025] 1. By utilizing various tooling fixtures, the assembly process of the dual-energy electron gun is standardized into a welding assembly process. The overall welding process can be broken down into the welding of individual small parts, forming a standardized production process. During assembly, it is only necessary to put the parts into the tooling fixtures and tighten the corresponding screws, which reduces the difficulty of operation. After simple training, operators can operate the equipment. Fixed personnel perform the prescribed welding procedures, which significantly reduces personnel training costs. This is conducive to step-by-step welding, and each small part is inspected and qualified before entering the next process, thereby improving the yield rate.

[0026] 2. By utilizing various tooling fixtures, the operational difficulty of each step with high precision requirements is reduced. High-precision welding can be achieved simply by using the tooling fixtures for assembly, reducing operational difficulty. The forced locking in the tooling fixtures ensures that the installation dimensions of the parts will not change due to stress during the welding process, making the product easy to weld.

[0027] 3. This invention enables controllable and measurable key dimensions of the electron gun during assembly, reducing human error and ensuring assembly accuracy. The invention employs high-precision fixtures that allow adjustment of the distance and concentricity tolerances between the cathode, control electrode, and anode, ensuring that tolerances are controlled within design requirements during and after welding. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the dual-energy electron gun structure of the accelerator tube assembly method of the present invention.

[0030] Figure 2 This is a cross-sectional structural diagram of the dual-energy electron gun in the assembly method of the dual-energy electron gun for accelerating tubes according to the present invention.

[0031] Figure 3 This is a schematic diagram of the anode transition assembly structure of a dual-energy electron gun in an accelerator tube assembly method according to the present invention.

[0032] Figure 4 This is a cross-sectional view along the line of symmetry of the anode transition assembly of the dual-energy electron gun in the present invention, which is a method for assembling a dual-energy electron gun for accelerating tubes.

[0033] Figure 5 This is a schematic diagram of the sealing fixture used in the assembly method of a dual-energy electron gun for accelerating tubes according to the present invention.

[0034] Figure 6 This is a schematic diagram of the structure cut open during use of the sealing tooling for the assembly method of a dual-energy electron gun for accelerating tubes according to the present invention.

[0035] Figure 7 This is a schematic diagram of the argon arc welding fixture used in the assembly method of the dual-energy electron gun for accelerating tubes according to the present invention.

[0036] Figure 8 This is a schematic diagram of the cross-section of the welding fixture for the cathode component in the assembly method of the dual-energy electron gun for accelerating tubes according to the present invention.

[0037] Figure 9 This is a schematic diagram of the cathode positioning fixture used in the assembly method of the dual-energy electron gun for accelerating tubes according to the present invention.

[0038] The markings in the diagram are as follows: 1. Electron gun; 11. Ceramic gun housing sealing assembly; 111. Gun housing; 112. Upper sealing plate; 113. Middle sealing plate; 114. Lower sealing plate; 12. Anode transition assembly; 121. Anode transition ring; 122. Argon arc welding edge; 123. Anode mounting plate; 13. Cathode control component; 131. Cathode assembly; 1311. Cathode lead; 1312. Heat shield cylinder; 132. Connecting sleeve.

[0039] 2. Sealing fixture 21. Center positioning post a 22. Edge limiting barrier 221. Limiting groove 23. Assembly block a

[0040] 3. Argon arc welding fixture 31. Center positioning post b 311. Mounting base 312. Positioning section 32. Assembly block b 33. Bottom locking screw 34. Top locking screw

[0041] 4. Welding fixture for female control components 41. Base a 411. Boss 412. Mounting hole 42. Locating pin

[0042] 5. Cathode positioning fixture 51. Base b 52. Mounting screws 53. Positioning screws Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of this invention, not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. Therefore, the detailed description of the embodiments of this invention provided below is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Example

[0045] like Figure 1 The diagram shows a method for assembling a dual-energy electron gun for an accelerator tube. The assembly steps are as follows:

[0046] S1, gun casing sealing: The sealing tool 2 is used to limit the position of the sealing plate, thereby sealing the gun casing 111 of the electron gun 1 to obtain the ceramic gun casing sealing assembly 11.

[0047] S2, Anode transition assembly sealing: The anode transition ring 121 and the argon arc welding edge 122 are sealed together, and then the anode transition ring 121 is installed on the anode mounting plate 123 using the mating stop at the lower end of the anode transition ring 121 for positioning, thus obtaining the anode transition assembly 12;

[0048] S3, Gun casing argon arc welding: 3.1) Assemble the anode transition assembly 12 onto the argon arc welding fixture 3 and lock it with the bottom locking screw 33.

[0049] 3.2) The argon arc welding fixture 3 is positioned by fitting into the inner hole of the intermediate sealing plate 113, thereby assembling the ceramic gun shell sealing assembly 11 and the anode transition assembly 12. Then, the upper end of the argon arc welding fixture 3 is locked from the upper end of the gun shell 111 by the mounting block and the top locking screw 34, so that the argon arc welding edge 122 contacts the lower sealing plate 114, and argon arc welding is performed on the contact position to obtain the welded electron gun shell assembly 111. The argon arc welding edge 122 is an L-shaped cylinder, and the two adjacent inner walls contact the anode transition ring 121 and the lower sealing plate 114 respectively to achieve installation. After welding, there is a certain gap between the lower end of the gun shell 111 and the anode transition ring 121.

[0050] S4, Cathode heat shield cylinder welding: The upper and lower ends of the inner wall in contact with the cathode and the heat shield cylinder 1312 are fixed by spot welding to form the cathode assembly 131;

[0051] S5, Cathode component welding: S5.1 Fix the cathode assembly 131 using the cathode component welding fixture 4; S5.2 Lock the connecting sleeve 132 onto the cathode component welding fixture 4 using screws, use a dial indicator to test the parallelism between the connecting sleeve 132 and the cathode assembly 131, and after the test is qualified, laser weld the cathode component 13 to be fixed, then remove the cathode component welding fixture 4, measure the distance of the cathode component 13 to reach the preset value, and wipe the laser weld point;

[0052] S6, Electron Gun Assembly: S6.1 Install the cathode control component 13 into the cathode positioning fixture 5. This step uses three M3X16 screws for tightening. Then, use a dial indicator to check the parallelism of the gun housing 111 surface to confirm that the installation is in place. S6.2 Invert the cathode control component 13 installed in the cathode positioning fixture 5 and install it on the upper end of the welded electron gun housing assembly 111 for tightening. At this time, the welded electron gun housing assembly 111 is placed upside down and located inside the gun housing 111. The cathode positioning fixture 5 is pressed down and tightened by its own weight. S6.3 After checking that the fit is in place, laser weld it in place and re-measure the mounting dimensions and cold resistance.

[0053] S7, Argon Arc Welding: Install the electron gun cover plate and perform argon arc welding on the entire electron gun. Additionally, this invention involves the installation and disassembly of tooling. The tooling can be disassembled after welding has cooled (or when the temperature drops to a threshold). This can be easily determined based on actual use; simply remove it after ensuring the welding is secure, without affecting subsequent processing.

[0054] Before welding, various tooling can be used to ensure that the assembly dimensions, concentricity and flatness are in place. The dimensions are fixed by tightening screws. Before welding, the assembly can be checked by dial indicator. If the requirements are not met, the screws can be adjusted multiple times until the requirements are met, thus ensuring the concentricity and dimensions of the assembly.

[0055] In step S1, the sealing fixture 2 includes a central positioning post a21 and an edge limiting barrier 22. The central positioning post a21 is a three-section cylindrical structure. The lower section is a disc for receiving the gun housing 111. The middle section is a cylinder with a diameter matching the diameter of the middle hole of the lower sealing plate 114. The upper section is a cylinder with a diameter matching the diameter of the middle sealing plate 113. The upper section cooperates with the middle hole of the assembly block a23 to achieve the concentricity of the central positioning post a21 and the gun housing 111. The assembly block a is provided with a step that matches the size of the upper end of the gun housing 111 for positioning. The edge limiting barrier 22 is attached to the middle of the gun housing 111, and the lower end of the edge limiting barrier 22 is attached to the upper surface of the disc as a reference plane. A limiting groove 221 is provided on the inner side of the edge limiting barrier 22. The height and depth of the limiting groove 221 are used to control the height of each sealing plate and / or the coaxiality with the gun housing 111.

[0056] The inner diameter of the upper sealing plate 112 is larger than the diameter of the upper section. The upper sealing plate 112 fully utilizes the edge limiting barrier 22 to control its height and coaxiality with the gun housing 111. The middle hole of the middle sealing plate 113 engages with the upper section of the central positioning post a21 to control its coaxiality with the gun housing 111, and its height is controlled by the edge limiting barrier 22. The lower sealing plate 114 uses the edge limiting barrier 22 to control its height and coaxiality with the gun housing 111, and further adjusts its coaxiality with the gun housing 111 by engaging with the central positioning post a21 through the middle hole of the lower sealing plate 114.

[0057] In step S3, the argon arc welding fixture 3 includes a central positioning post b31, an assembly block b32, a bottom locking screw 33, and a top locking screw 34. The central positioning post b31 is a two-section cylindrical structure, with a mounting base 311 at the lower end and a positioning section 312 at the upper end. A step is provided on the mounting base 311 to cooperate with the internal step of the anode transition ring 121 to achieve installation and positioning. The anode transition ring 121 is fixed to the central positioning post b31 by the bottom locking screw. The assembly block b32 is used to install the top locking screw 34 from the upper end of the gun shell 111. The top locking screw 34 passes through the assembly block b32 and connects to the mounting hole 412 located on the centerline at the upper end of the central positioning post b31. This also serves as a central positioning function. That is, the assembly block b is both a receiving structure and a positioning structure.

[0058] In step S5, the cathode control component welding fixture 4 includes a base a41 and a positioning pin 42. The base a41 is provided with a boss 411 for engaging with the inner groove on the cathode assembly 131 to fix and position the cathode assembly 131. The lower end of the connecting sleeve 132 is fitted onto the outer edge of the cathode assembly 131 for positioning. The base a41 is provided with a mounting hole 412 for fixing the connecting sleeve 132 to the base a41 with screws. A pin hole is provided in the center of the boss 411 on the base a41. The positioning pin 42 passes through the central hole of the focusing electrode to install and position the focusing electrode on the base a41. The installation method using the positioning pin 42 can also conveniently determine the position of the cathode lead 1311 and prevent its deviation.

[0059] In step S6, the cathode positioning fixture 5 includes a base b51, mounting screws 52, and positioning screws 53. The cathode control component 13 is installed on the base b51 through the process hole on the connecting sleeve 132 using mounting screws 52. The base b51 is provided with a step for positioning in conjunction with the anode transition ring. The base b51 is installed on the anode transition ring by positioning screws 53, and the cathode positioning fixture 5 is inverted and pressed down by the weight of the base b51 itself.

[0060] In steps S5.2 and S6.3, the parallelism accuracy requirement is ±0.01mm-±0.04mm. In step S6.3, the remeasured mounting dimensions should maintain consistency, the cold resistance requirement should be less than the threshold, and preferably the accuracy requirement in step S5.2 should be higher than that in step S6.3. This ensures better adaptability for subsequent steps in step S5.2, preventing situations where the required accuracy is difficult to meet.

[0061] In laser steps S5.2 and S6.4, the laser weld joints must be wiped with a silk cloth and the spattered welding slag must be cleaned to ensure that the surface of the weld joints is smooth and free of welding slag residue, so as to avoid affecting subsequent processing and product quality.

[0062] In step S5.2, the parallelism requirement is ±0.02mm; in step S6.3, the parallelism requirement is ±0.03mm.

[0063] Process holes are provided in the anode transition ring 121 and the connecting sleeve 132 for bolt installation and positioning with the argon arc welding fixture 3, the cathode control component welding fixture 4, and the cathode positioning fixture 5. Of course, the position, size, and number of process holes can be set according to actual needs, as long as it does not affect product quality.

[0064] This invention utilizes multiple tooling fixtures for positioning. The specific location of the solder joints is not directly described, but the solder joints are basically the same as those of existing dual-energy electron guns (the design principle is the same, and the structure has only minor differences, so the location of the solder joints will not be described). The invention focuses on using tooling to break down the welding steps into a step-by-step welding method, which simplifies the operation, optimizes the process, and reduces the difficulty of training.

[0065] Operating instructions: When installing the sealing fixture 2, argon arc welding fixture 3, cathode control component welding fixture 4, and cathode positioning fixture 5, it is required that there be no gap between them and the contact parts.

[0066] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0067] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0068] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0069] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. For those skilled in the art, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for assembling a dual-energy electron gun for accelerating tubes, characterized in that, The assembly steps are as follows: S1, Gun casing sealing: The sealing plate position is defined by the sealing tool, thereby sealing the gun casing of the electron gun to obtain a ceramic gun casing sealing assembly. S2, Anode transition assembly sealing: The anode transition ring and the argon arc weld edge are sealed together, and then the anode transition ring is installed on the anode mounting plate using the mating stop at the lower end of the anode transition ring for positioning, thus obtaining the anode transition assembly; S3, Gun casing TIG welding: 3.1) Assemble the anode transition assembly onto the TIG welding fixture and tighten it with the bottom locking screw; 3.2) Position the ceramic gun shell sealing assembly and the anode transition assembly by fitting the argon arc welding fixture into the inner hole of the intermediate sealing plate. Then, use the mounting block and the top locking screw at the upper end of the argon arc welding fixture to lock the anode transition assembly from the upper end of the gun shell, so that the argon arc welding edge contacts the lower sealing plate, and perform argon arc welding at the contact position to obtain the welded electron gun shell assembly. S4, Cathode heat shield cylinder welding: The upper and lower ends of the inner wall in contact with the cathode and the heat shield cylinder are fixed by spot welding to form a cathode assembly; S5, Cathode component welding: S5.1 Fix the cathode assembly using the cathode component welding fixture; S5.2 Lock the connecting sleeve onto the cathode component welding fixture using screws, use a dial indicator to test the parallelism between the connecting sleeve and the cathode assembly, and after the test is qualified, laser weld the connecting sleeve and the cathode assembly to obtain the cathode component, then remove the cathode component welding fixture, measure the distance between the cathode component and the preset value, and wipe the laser weld point; S6, Electron Gun Assembly: S6.1 Install the cathode control component into the cathode positioning fixture, then use a dial indicator to check the parallelism of the gun housing surface to confirm proper installation; S6.2 Invert the cathode control component installed on the cathode positioning fixture and install it on the upper end of the welded electron gun housing assembly for locking. At this time, the welded electron gun housing assembly is placed upside down, using the weight of the cathode positioning fixture itself to press and tighten it; S6.3 After checking that the fit is in place, the welded electron gun housing assembly and cathode control component are fixed by laser welding, and the mounting dimensions and cold resistance are re-measured; S7, Argon Arc Welding: Install the electron gun cover plate and perform argon arc welding on the entire electron gun.

2. The method for assembling a dual-energy electron gun for an accelerator tube according to claim 1, characterized in that, In step S1, the sealing fixture includes a central positioning post a and an edge limiting barrier. The central positioning post a is a three-section cylindrical structure. The lower section is a disc for receiving the gun shell; the middle section is a cylinder with a diameter matching the diameter of the middle hole of the lower sealing plate; and the upper section is a cylinder with a diameter matching the diameter of the middle sealing plate. The upper section cooperates with the middle hole of the assembly block a to ensure the concentricity of the central positioning post a and the gun shell. The assembly block a is provided with a step that matches the size of the upper end of the gun shell for positioning. The edge limiting barrier is attached to the middle of the gun shell, and the lower end of the edge limiting barrier is attached to the upper surface of the disc as a reference plane. A limiting groove is provided on the inner side of the edge limiting barrier. The height and depth of the limiting groove are used to control the height of each sealing plate and / or the coaxiality with the gun shell.

3. The method for assembling a dual-energy electron gun for an accelerator tube according to claim 2, characterized in that, The inner diameter of the upper sealing plate is larger than the diameter of the upper section. The upper sealing plate fully utilizes the edge limiting barrier to control its height and coaxiality with the gun casing. The hole in the middle of the middle sealing plate engages with the upper section of the central positioning post a to control its coaxiality with the gun casing, and its height is controlled by the edge limiting barrier. The lower sealing plate uses the edge limiting barrier to control its height and coaxiality with the gun casing, and further adjusts its coaxiality with the gun casing by engaging with the central positioning post a through the hole in the middle of the lower sealing plate.

4. The method for assembling a dual-energy electron gun for an accelerator tube according to claim 1, characterized in that, In step S3, the argon arc welding fixture includes a central positioning post b, an assembly block b, a bottom locking screw, and a top locking screw. The central positioning post b is a two-section cylindrical structure, with a mounting base at the lower end and a positioning section at the upper end. A step is provided on the mounting base to cooperate with the internal step of the anode transition ring to achieve installation and positioning. The anode transition ring is fixed to the central positioning post b by the bottom locking screw. The assembly block b is used to install the top locking screw from the upper end of the gun shell. The top locking screw passes through the assembly block b and connects to the mounting hole located at the centerline at the upper end of the central positioning post b.

5. The method for assembling a dual-energy electron gun for an accelerator tube according to claim 1, characterized in that, In step S5, the cathode component welding fixture includes a base a and a positioning pin. The base a has a boss for engaging with the inner groove on the cathode assembly to fix and position the cathode assembly. The lower end of the connecting sleeve is fitted onto the outer edge of the cathode assembly for positioning. The base a has a mounting hole for screws to fix the connecting sleeve on the base a. A pin hole is provided in the center of the boss on the base a. The positioning pin passes through the central hole of the focusing electrode to install and position the focusing electrode on the base a.

6. The method for assembling a dual-energy electron gun for an accelerator tube according to claim 1, characterized in that, In step S6, the cathode positioning fixture includes a base b, mounting screws, and positioning screws. The cathode control component is installed on the base b using mounting screws through the process holes on the connecting sleeve. The base b is provided with a step for positioning in conjunction with the anode transition ring. The base b is installed on the anode transition ring by positioning screws, and the welded electron gun housing assembly is inverted and pressed down by the weight of the base b itself.

7. The method for assembling a dual-energy electron gun for an accelerator tube according to claim 1, characterized in that, In steps S5.2 and S6.3, the laser solder joints must be wiped with a silk cloth and the spattered solder slag must be cleaned.

8. The method for assembling a dual-energy electron gun for an accelerator tube according to claim 1, characterized in that, The parallelism accuracy requirement in steps S5.2 and S6.3 is 0.01mm-0.04mm.

9. The method for assembling a dual-energy electron gun for an accelerator tube according to claim 8, characterized in that, In step S6.3, the dimensions of the retested mounting bracket must remain consistent, and the cold resistance must be less than the threshold value.

10. The method for assembling a dual-energy electron gun for an accelerator tube according to claim 1, characterized in that, Process holes are provided in the anode transition ring and connecting sleeve for bolt installation and positioning with argon arc welding fixtures, cathode control component welding fixtures, and cathode positioning fixtures.

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