Radio frequency superconducting cavity inner conductor and outer conductor welding tool and welding method

Abstract

A kind of radio frequency superconducting cavity inner conductor and outer conductor welding tool, including outer weld auxiliary tool, inner weld auxiliary tool;Outer weld auxiliary tool includes limiting pull rod, and first limiting plate, second limiting plate are oppositely arranged;Two ends of limiting pull rod are respectively penetrated first limiting plate, second limiting plate, realize to outer conductor realizes clamping fixed;Inner weld auxiliary tool includes first pressure head, second pressure head and is oppositely arranged;First pressure head, second pressure head are all equipped with exhaust hole, the side of second pressure head towards first pressure head forms the arc structure compatible with outer conductor, and first pressure head and second pressure head between install the fixed rod that inner conductor and outer conductor are assembled into an entity.This application also provides a kind of radio frequency superconducting cavity inner conductor and outer conductor welding method.This application solves the welding problem of outer conductor special structure, guarantees the welding quality;Reduce the thermal deformation of the elliptic surface structure with specific size when welding with inner conductor, guarantee the welding precision.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency superconducting cavities, and in particular to a welding tool and a welding method for an inner conductor and an outer conductor of a radio frequency superconducting cavity. Background Art

[0002] A Spoke-type superconducting cavity typically consists of an end cap, an inner conductor, an outer conductor, a coupling tube, and a flange. Vacuum electron beam welding is used to manufacture a radio frequency superconducting cavity with a specific resonant frequency that meets design requirements. The 648MHzβ=0.4 single-Spoke radio frequency superconducting cavity has essentially the same structure as the original single-Spoke radio frequency superconducting cavity, but with a special physical design structure on the outer conductor. This is primarily due to the presence of an elliptical curved surface of specific dimensions on the outer conductor at the interface where the outer and inner conductors are welded. According to design requirements, the weld seam between the inner and outer conductors must be free of undercuts, holes, and other welding defects after welding. During operation of the radio frequency superconducting cavity, the electric field at the weld is relatively strong, and any resulting welding defects can cause tip discharge, generating free electrons that enter the acceleration gap and affect beam quality. Furthermore, according to design requirements, no R-angles should appear on the internal welds after welding.

[0003] The outer conductor of the 648MHz single-Spoke040 RF superconducting cavity is processed using conventional single-Spoke RF superconducting cavity outer conductor monolithic methods. However, the outer conductor contains an elliptical surface structure of specific dimensions, which cannot be achieved during processing. According to the design requirements of the 648MHz single-Spoke040 RF superconducting cavity, the weld formed after the inner and outer conductors are assembled must not have any internal rounded corners (chamfers or fillets). The weld between the inner and outer conductors must also be free of weld defects such as undercuts and holes. Because the electric field at the weld is strong during RF superconducting cavity operation, weld defects can cause tip discharges, generating free electrons that enter the acceleration gap and affect beam quality. Therefore, the "one-side welding, two-side shaping" method cannot be used. A single weld can only be made using both the inner and outer sides. Furthermore, due to the cylindrical structure of the outer conductor, the obstruction of the components prevents the electron beam welder from completing both the inner and outer sides. Summary of the Invention

[0004] In order to solve the technical problems existing in the above technologies, it is necessary to provide a welding tool for the conductor inside and outside the radio frequency superconducting cavity.

[0005] A welding tool for an inner conductor and an outer conductor of a radio frequency superconducting cavity, comprising an outer welding seam auxiliary tool and an inner welding seam auxiliary tool;

[0006] The external weld auxiliary tooling includes a first limiting plate, a second limiting plate, and a limiting pull rod; the first limiting plate and the second limiting plate are arranged opposite to each other, and the two ends of the limiting pull rod respectively pass through the first limiting plate and the second limiting plate and then fix the first limiting plate and the second limiting plate, so that the first limiting plate and the second limiting plate can clamp the outer conductor to limit the axial displacement and radial displacement of the outer conductor;

[0007] The inner weld auxiliary tooling includes a first pressing head and a second pressing head for pressing the outer conductor at both ends of the inner conductor; the first pressing head and the second pressing head are arranged opposite to each other, and exhaust holes are provided on the first pressing head and the second pressing head; the second pressing head forms an arc structure adapted to the outer conductor on the side facing the first pressing head; a fixing rod is installed between the first pressing head and the second pressing head, so that the first pressing head and the second pressing head assemble the inner conductor and the outer conductor into one.

[0008] Preferably, a surface of the first limiting plate facing the second limiting plate and a surface of the second limiting plate facing the first limiting plate are both provided with limiting columns adapted to the inner diameter of the outer conductor.

[0009] Preferably, a limiting groove concentric with the limiting column is provided on the surface of the first limiting plate facing the second limiting plate and the surface of the second limiting plate facing the first limiting plate, and the inner diameter of the limiting groove is the same as the diameter of the limiting column.

[0010] Preferably, the first limiting plate and the second limiting plate are both provided with corresponding fixing through holes, and a fastening rod which can be inserted into the fixing through holes is installed between the first limiting plate and the second limiting plate to realize the assembly of the first limiting plate and the second limiting plate.

[0011] Preferably, a connecting sleeve for connecting to an electron beam welder is provided on the surface of the first limiting plate away from the second limiting plate; a connecting head for connecting to an electron beam welder is installed on the side of the first pressing head away from the second pressing head.

[0012] A method for welding a radio frequency superconducting cavity conductor and an outer conductor, using the above-mentioned radio frequency superconducting cavity conductor and outer conductor welding tool for welding, comprises the following steps:

[0013] Step S1: Using an external welding seam auxiliary tooling to assemble the inner conductor and the outer conductor into one piece, assembling the two outer conductors at the two ends of the inner conductor, and loading the pieces into the welding chamber of the electron beam welder; after vacuuming to meet the process requirements, welding the outer seams of the outer conductor and the inner conductor using a corresponding welding process; after welding is completed, removing the external welding seam auxiliary tooling;

[0014] Step S2: Using an inner weld auxiliary tool, the outer conductor and the inner conductor, which have been welded to the outer weld, are reassembled into one piece and placed into the welding chamber of the electron beam welder; after vacuuming to meet the process requirements, the inner weld of the outer conductor and the inner conductor is welded using a corresponding welding process; after welding is completed, the inner weld auxiliary tool is removed;

[0015] Step S3: Use the outer weld auxiliary tooling to reassemble the remaining outer conductor and the workpiece welded in step S2 into one piece, so that the remaining outer conductor and the welded outer conductor form a ring structure, and load it into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the welds between adjacent outer conductors; after welding is completed, remove the outer weld auxiliary tooling, and the inner conductor and the outer conductor can be welded as a whole.

[0016] Preferably, in step S1, the outer conductor and the outer weld of the inner conductor are welded in the following manner:

[0017] S11: First, assemble the first limiting plate and the connecting sleeve and tighten them with screws to form a composite tooling;

[0018] S12: After the superconducting cavity conductor and the two outer conductors are assembled, the whole is assembled in conjunction with the composite tooling in step S11, so that the two outer conductors are inserted into the limiting grooves of the first limiting plate, and the inner surfaces are closely attached to the limiting pillar surfaces of the first limiting plate;

[0019] S13: Install the limiting pull rod in the center hole of the inner conductor and the center hole of the first limiting plate, and assemble them in place;

[0020] S14: Install the second limiting plate so that the limiting rod passes through its center hole. The two outer conductors are clamped in the limiting grooves of the second limiting plate, with the inner surfaces tightly fitting against the limiting posts of the second limiting plate. At the same time, the fixing through holes on the second limiting plate and the first limiting plate are aligned with each other.

[0021] S15: After confirming that the two outer conductors are correctly mounted in the limiting grooves of the first limiting plate and the second limiting plate, and that the inner surfaces are tightly fitted on the limiting posts of the first limiting plate and the second limiting plate, fastening rods are installed in the fixing through holes of the first limiting plate and the second limiting plate, and both ends are fastened with nuts. At the same time, nuts are additionally installed on both ends of the limiting pull rod for fastening.

[0022] S16: Place the weldment and the fastener of the tooling horizontally into the welding chamber of the electron beam welder, and fasten the connecting sleeve into the welding machine chuck; after vacuuming to meet the process requirements, use the corresponding welding process to weld the outer welds of the outer conductor and the inner conductor; after welding is completed, remove the outer weld auxiliary tooling.

[0023] Preferably, in step S16, the following method is used when welding the outer weld of the outer conductor and the inner conductor:

[0024] After the vacuum reaches the process requirements, the first spot welding method is used to spot weld the outer weld formed by the first outer conductor and the inner conductor;

[0025] After spot welding is completed, the weldment and the tooling are rotated 180° by the welding machine chuck, and the second outer conductor and the outer weld of the inner conductor are spot welded first, and then the corresponding welding process is used to formally weld this weld;

[0026] After welding is completed, the weldment and the tooling are rotated 180° by the welding machine chuck, and the corresponding welding process is used to formally weld the first outer conductor and the outer weld of the inner conductor.

[0027] Preferably, in step S2, the welding of the outer conductor and the inner weld of the inner conductor is carried out in the following manner:

[0028] S21: Assemble the first pressing head and the connecting sleeve together and fasten them together with a fixing rod to form a composite tool;

[0029] S22: Fitting the outer surface of the first outer conductor of the welded body with the first pressing head in the composite tooling; clamping the second pressing head into the inner conductor at the end of the second outer conductor, while aligning the screw hole on the second pressing head with the screw hole on the first pressing head; then inserting a fixing rod into the screw hole and tightening it with a nut to integrate the weldment with the welding tooling;

[0030] S23: Clamp the connecting sleeve into the chuck in the welding chamber of the electron beam welder. The elevation angle of the welder chuck is 42°. After the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the internal welds of the outer conductor and the inner conductor. After welding is completed, remove the internal weld auxiliary tooling.

[0031] Preferably, in step S23, the following method is used when welding the inner weld of the outer conductor and the inner conductor:

[0032] After the vacuum is exhausted to meet the process requirements, the inner weld of the inner conductor and the first outer conductor is welded according to the welding process. After welding, the inner weld of the inner conductor and the first outer conductor is removed from the furnace after meeting the furnace conditions. The inner weld of the inner conductor and the first outer conductor is completed.

[0033] After rotating the weldment 180°, the end of the second outer conductor is engaged with the first pressing head, and the above steps are repeated to complete the internal weld of the inner conductor and the second outer conductor.

[0034] Compared with the prior art, the welding tooling and welding method for the RF superconducting cavity inner conductor and outer conductor provided by the present invention divides the outer conductor into a plurality of independent parts, wherein the parts to be welded in combination with the inner conductor have an elliptical surface structure of a specific size. The designed outer weld auxiliary tooling and inner weld auxiliary tooling are used to fix and clamp the parts. The inner conductor is first welded to two outer conductor parts with an elliptical surface structure of a specific size to form a welded body. Then, the welded body is assembled with other parts using the welding tooling to weld them into a complete outer conductor. The present invention solves the welding problem of the special structure of the outer conductor, realizes the purpose of coinciding the central axis of the inner conductor with the arc axis of the two pieces of the outer conductor, and ensures the welding quality; reduces the thermal deformation of the elliptical surface structure with a specific size when welded to the inner conductor; forms a method for electron beam welding of the 648MHz single-Spoke type RF superconducting cavity inner conductor and outer conductor assembly, and ensures the welding accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 It is a structural schematic diagram of the external weld auxiliary tooling of the present invention.

[0037] Figure 2 For the present invention Figure 1 Schematic diagram of the structure from another angle.

[0038] Figure 3 This is a schematic structural diagram of the outer weld auxiliary tooling of the present invention when clamping the outer conductor and the inner conductor.

[0039] Figure 4 This is a structural schematic diagram of the internal weld auxiliary tooling of the present invention.

[0040] Figure 5 For the present invention Figure 4 Schematic diagram of the structure from another angle.

[0041] Figure 6 It is a structural schematic diagram of the inner weld auxiliary tooling of the present invention when clamping the outer conductor and the inner conductor.

[0042] Figure 7 This is a schematic diagram of welding an external weld according to the present invention.

[0043] Figure 8 This is a schematic diagram of welding an internal weld according to the present invention.

[0044] Figure 9 It is a structural schematic diagram of the first limiting plate of the present invention.

[0045] In the figure: the first limiting plate 01, the limiting column 11, the limiting groove 12, the fixing through hole 13, the second limiting plate 02, the limiting pull rod 03, the first pressure head 04, the second pressure head 05, the exhaust hole 06, the fixing rod 07, the fastening rod 08, the connecting sleeve 09, the connector 10, the first outer conductor 20, the second outer conductor 30, the inner conductor 40, and the screw hole 50. DETAILED DESCRIPTION

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0047] In the description of the present invention, it should be understood that the terms "upper", "middle", "outer", "inner", "lower" and the like indicating directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific direction, be constructed and operate in a specific direction, and therefore should not be understood as limiting the present invention.

[0048] Please see Figures 1 to 6 , the present invention provides a welding tool for a radio frequency superconducting cavity inner conductor and an outer conductor, comprising an outer welding seam auxiliary tool and an inner welding seam auxiliary tool;

[0049] Among them, the external weld auxiliary tooling includes a first limit plate 01, a second limit plate 02, and a limit rod 03; the first limit plate 01 and the second limit plate 02 are arranged opposite each other, and the two ends of the limit rod 03 pass through the first limit plate 01 and the second limit plate 02 respectively, and then fix the first limit plate 01 and the second limit plate 02, so that the first limit plate 01 and the second limit plate 02 can clamp the outer conductor to limit the axial displacement and radial displacement of the outer conductor. The two ends of the limit rod 03 are correspondingly provided with top holes to facilitate the insertion of the welding machine top. Among them, the fastening rod 08 can adopt a screw with threads at both ends to facilitate the adaptation and fastening of the nut.

[0050] The internal weld auxiliary tooling includes a first pressing head 04 and a second pressing head 05, which are used to press the outer conductor at both ends of the inner conductor 40. The first and second pressing heads 04 and 05 are arranged in opposing positions. Each of the first and second pressing heads 04 and 05 features exhaust holes 06, which allow fumes and air generated during welding to be discharged, while also dissipating some welding heat. The second pressing head 05 has an arc-shaped structure facing the first pressing head 04, which conforms to the outer conductor. This prevents deformation of the elliptical surface of a specific size during assembly of the weldment and prevents thermal deformation caused by welding the inner weld bead. A fixing rod 07 is installed between the first and second pressing heads 04 and 05, allowing the first and second pressing heads 04 and 05 to assemble the inner and outer conductors into a single piece. Both the first and second pressing heads 04 and 05 feature screw holes 50 for the fixing rod 07 to pass through. The fixing rod 07 is threaded at both ends to facilitate fastening with a nut.

[0051] Please see Figure 9 In one embodiment, limiting posts 11 that match the inner diameter of the outer conductor are provided on the surface of the first limiting plate 01 facing the second limiting plate 02, and on the surface of the second limiting plate 02 facing the first limiting plate 01. These limiting posts 11 limit the inner diameter of the weldment and ensure the roundness of the weldment.

[0052] Of course, a center positioning hole is also opened in the middle position of the first limiting plate 01 toward the second limiting plate 02, and the center positioning hole is used to insert the limiting pull rod 03. The center of the center positioning hole is concentric with the circle of the limiting column 11, ultimately ensuring the coaxial accuracy of the center hole of the inner conductor 40 and the intermediate ring.

[0053] Specifically, a concentric limiting groove 12 is formed on the surface of the first limiting plate 01 facing the second limiting plate 02, and on the surface of the second limiting plate 02 facing the first limiting plate 01. The inner diameter of the limiting groove 12 is the same as the diameter of the limiting column 11. The limiting groove 12 is formed by the difference in diameter between the inner and outer concentric circles and a certain depth, and is used to fix and position the outer conductor so that the diameter of the weldment meets the design requirements of the outer conductor.

[0054] Specifically, the first and second limiting plates 01 and 02 are each provided with corresponding fixing holes 13. A fastening rod 08, which can be inserted into the fixing holes 13, is installed between the first and second limiting plates 01 and 02 to facilitate assembly of the first and second limiting plates 01 and 02. By fastening the fastening rod 08 in conjunction with the nut, the weldment assembled between the first and second limiting plates 01 and 02 can be secured securely, thereby increasing welding precision.

[0055] In one embodiment, a connection sleeve 09 for connecting to an electron beam welder is provided on the surface of the first limit plate 01 away from the second limit plate 02. A connector 10 for connecting to an electron beam welder is installed on the side of the first pressure head 04 away from the second pressure head 05.

[0056] In one embodiment, the present invention provides a method for welding a radio frequency superconducting cavity conductor and an outer conductor, which is performed using a radio frequency superconducting cavity conductor and an outer conductor welding tool, comprising the following steps:

[0057] Step S1: Use the outer weld auxiliary tooling to assemble the inner conductor 40 and the outer conductor into one piece, so that the two outer conductors are assembled at the two ends of the inner conductor 40, and then load them into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the outer welds of the outer conductor and the inner conductor 40; after welding is completed, remove the outer weld auxiliary tooling.

[0058] Step S2: Use the inner weld auxiliary tooling to reassemble the outer conductor and the inner conductor 40 after the outer weld is completed, and load them into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the inner weld of the outer conductor and the inner conductor 40; after welding is completed, remove the inner weld auxiliary tooling.

[0059] Step S3: Use the outer weld auxiliary tooling to reassemble the remaining outer conductor and the workpiece welded in step S2 into one piece, so that the remaining outer conductor and the welded outer conductor form a ring structure, and load it into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the welds between adjacent outer conductors; after welding is completed, remove the outer weld auxiliary tooling, and the inner conductor 40 and the outer conductor can be welded as a whole.

[0060] Please see Figure 7 Of course, to be more specific, in step S1, the outer conductor and the inner conductor 40 are welded together in the following manner:

[0061] S11: First, assemble the first limiting plate 01 and the connecting sleeve 09 and fasten them with screws to form a composite tooling.

[0062] S12: After the superconducting cavity conductor 40 is assembled with the two outer conductors, the whole is installed in conjunction with the composite tooling in step S11, so that the two outer conductors are inserted into the limiting groove 12 of the first limiting plate 01, and the inner surface is tightly fitted on the surface of the limiting column 11 of the first limiting plate 01; the purpose is to make the arc curvature of the first outer conductor 20 and the second outer conductor 30 after welding consistent with the design curvature of the outer conductor.

[0063] S13: Install the limiting rod 03 in the center hole of the inner conductor 40 and the center hole of the first limiting plate 01, and assemble them in place; to play a positioning and fixing role, the purpose is to make the center axis of the outer conductor coincide with the center axis of the inner conductor 40 to meet the process requirements.

[0064] S14: Install the second limiting plate 02 so that the limiting rod 03 passes through its center hole. The two outer conductors are clamped in the limiting groove 12 of the second limiting plate 02, and the inner surface is tightly fitted on the surface of the limiting column 11 of the second limiting plate 02. At the same time, the fixing through holes 13 on the second limiting plate 02 and the first limiting plate 01 are facing each other.

[0065] S15: After confirming that the two outer conductors are clamped in the limiting grooves 12 of the first limiting plate 01 and the second limiting plate 02, and that the inner surfaces are tightly fitted in the limiting columns 11 of the first limiting plate 01 and the second limiting plate 02, install the fastening rod 08 into the fixed through holes 13 on the first limiting plate 01 and the second limiting plate 02, and fasten the two ends with nuts. At the same time, install nuts at both ends of the limiting pull rod 03 for fastening. The purpose is to make the weldment and the welding tooling form a rigid whole to prevent the heat generated during electron beam welding from causing deformation of the weldment.

[0066] S16: The weldment and the fastener of the tooling are horizontally loaded into the welding chamber of the electron beam welder, and the connecting sleeve 09 is clamped into the welding machine chuck and fastened; after the vacuum is evacuated to meet the process requirements, the outer weld of the outer conductor and the inner conductor 40 is welded using the corresponding welding process; after the welding is completed, the outer weld auxiliary tooling is removed.

[0067] Please see Figure 8 Of course, to be more specific, in step S16, the following method is used when welding the outer seam of the outer conductor and the inner conductor 40:

[0068] After the vacuum is exhausted to meet the process requirements, the first outer weld formed by the outer conductor 20 and the inner conductor 40 is spot welded.

[0069] After the spot welding is completed, the weldment and the tooling are rotated 180 degrees by the welding machine chuck, and the outer weld of the second outer conductor 30 and the inner conductor 40 is first spot welded, and then the corresponding welding process is used to formally weld this weld;

[0070] After welding is completed, the weldment and the tooling are rotated 180 degrees by the welding machine chuck, and the first outer weld between the outer conductor 20 and the inner conductor 40 is formally welded using the corresponding welding process.

[0071] Of course, to explain in more detail, in step S2, the welding of the outer conductor and the inner weld of the inner conductor 40 is carried out in the following manner:

[0072] S21: Assemble the first pressing head 04 and the connecting sleeve, and fasten them into one body with the fixing rod 07 to form a composite tool.

[0073] S22: The outer surface of the first outer conductor 20 of the welded body with the outer weld completed is fitted together with the first press head 04 in the composite tooling; the second press head 05 is inserted into the end of the inner conductor 40 located at the second outer conductor 30, and the screw hole 50 on the second press head 05 is aligned with the screw hole 50 on the first press head 04; then the fixing rod 07 is installed in the screw hole 50 and fastened with a nut to make the weldment and the welding tooling become one; and the arc-shaped structural surface of the first press head 04 is exactly the same as the structure of the outer conductor, the purpose of which is to protect the elliptical surface structure of a specific size from thermal deformation when the internal weld is formed when welding the inner conductor 40 with the first outer conductor 20 and the second outer conductor 30, so as to ensure accuracy.

[0074] S23: Insert the connector sleeve into the chuck in the welding chamber of the electron beam welder. The chuck is tilted at a 42° angle. This tilt angle ensures that the electron beam generated by the electron beam welder can be unobstructed and continuously strike the internal weld bead while the chuck rotates the workpiece and the tooling 360 degrees during welding, ensuring a continuous and closed weld bead. After vacuuming to meet process requirements, weld the internal weld bead between the outer conductor and the inner conductor 40 using the corresponding welding process. After welding is completed, remove the internal weld auxiliary tooling.

[0075] Of course, to be more specific, in step S23, the following method is used when welding the inner seam of the outer conductor and the inner conductor 40:

[0076] After the vacuum is exhausted to meet the process requirements, the inner weld seam between the inner conductor 40 and the first outer conductor 20 is welded according to the welding process. After the welding is completed, the inner weld seam between the inner conductor 40 and the first outer conductor 20 is removed from the furnace after the furnace conditions are met. The inner weld seam between the inner conductor 40 and the first outer conductor 20 is welded.

[0077] After the weldment is rotated 180°, the end of the second outer conductor 30 is engaged with the first pressing head 04, and the above steps are repeated to complete the welding of the inner conductor 40 and the inner weld of the second outer conductor 30.

[0078] The above disclosure is only a preferred embodiment of the present invention, and it is certainly not intended to limit the scope of the present invention. A person skilled in the art can understand that all or part of the processes of the above embodiment and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A welding tool for a radio frequency superconducting cavity conductor and an outer conductor, characterized by: Including external welding auxiliary tooling and internal welding auxiliary tooling; The external weld auxiliary tooling includes a first limiting plate, a second limiting plate, and a limiting pull rod; the first limiting plate and the second limiting plate are arranged opposite to each other, and the two ends of the limiting pull rod respectively pass through the first limiting plate and the second limiting plate, and then the first limiting plate and the second limiting plate are fixed, so that the first limiting plate and the second limiting plate can clamp the outer conductor to limit the axial displacement and radial displacement of the outer conductor; a center positioning hole is opened in the middle position of the first limiting plate toward the second limiting plate, and the limiting pull rod is installed in the center hole of the inner conductor and the center positioning hole of the first limiting plate; The inner weld auxiliary tooling includes a first pressing head and a second pressing head for pressing the outer conductor at the two ends of the inner conductor; the first pressing head and the second pressing head are arranged opposite to each other, and exhaust holes are provided on the first pressing head and the second pressing head, and the second pressing head forms an arc structure adapted to the outer conductor on the side facing the first pressing head, and a fixing rod is installed between the first pressing head and the second pressing head, so that the first pressing head and the second pressing head assemble the inner conductor and the outer conductor into one; the surface of the first limiting plate facing the second limiting plate and the surface of the second limiting plate facing the first limiting plate are both provided with limiting columns adapted to the inner diameter of the outer conductor; the surface of the first limiting plate facing the second limiting plate and the surface of the second limiting plate facing the first limiting plate are both provided with limiting grooves concentric with the limiting columns, and the inner diameter of the limiting groove is the same as the diameter of the limiting column.

2. The welding tool for the radio frequency superconducting cavity conductor and the outer conductor according to claim 1, characterized in that: The first limiting plate and the second limiting plate are both provided with corresponding fixing through holes, and a fastening rod which can be inserted into the fixing through holes is installed between the first limiting plate and the second limiting plate to realize the assembly of the first limiting plate and the second limiting plate.

3. The welding tool for the radio frequency superconducting cavity conductor and the outer conductor according to claim 2, characterized in that: A connection sleeve for connecting to an electron beam welder is provided on the surface of the first limiting plate on the side away from the second limiting plate; a connection head for connecting to an electron beam welder is installed on the side of the first pressing head away from the second pressing head.

4. A method for welding a radio frequency superconducting cavity conductor and an outer conductor, using the radio frequency superconducting cavity conductor and outer conductor welding tool according to claim 3, characterized in that: The following steps are included: Step S1: Using an external welding seam auxiliary tool, assemble the inner conductor and the outer conductor into one piece, assemble the two outer conductors at the two ends of the inner conductor, and install them into the welding chamber of the electron beam welder; after vacuuming to meet the process requirements, weld the outer welds of the outer conductor and the inner conductor using a corresponding welding process; After welding is completed, remove the external weld auxiliary tooling; Step S2: Using an inner weld auxiliary tool, the outer conductor and the inner conductor, which have been welded to the outer weld, are reassembled into one piece and placed into the welding chamber of the electron beam welder; after vacuuming to meet the process requirements, the inner weld of the outer conductor and the inner conductor is welded using a corresponding welding process; after welding is completed, the inner weld auxiliary tool is removed; Step S3: Use the outer weld auxiliary tooling to reassemble the remaining outer conductor and the workpiece welded in step S2 into one piece, so that the remaining outer conductor and the welded outer conductor form a ring structure, and load it into the welding chamber of the electron beam welder; after the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the welds between adjacent outer conductors; after welding is completed, remove the outer weld auxiliary tooling, and the inner conductor and the outer conductor can be welded as a whole.

5. The method for welding a radio frequency superconducting cavity conductor and an outer conductor according to claim 4, characterized in that: In step S1, the outer conductor and the inner conductor are welded together in the following manner: S11: First, assemble the first limiting plate and the connecting sleeve and tighten them with screws to form a composite tooling; S12: After the superconducting cavity conductor and the two outer conductors are assembled and installed, the whole is assembled in conjunction with the composite tooling in step S11, so that the two outer conductors are inserted into the limiting grooves of the first limiting plate, and the inner surfaces are closely attached to the limiting pillar surfaces of the first limiting plate; S13: Install the limiting pull rod in the center hole of the inner conductor and the center positioning hole of the first limiting plate, and assemble them in place; S14: Install the second limiting plate so that the limiting rod passes through its center hole. The two outer conductors are clamped in the limiting grooves of the second limiting plate, with the inner surfaces tightly fitting against the limiting posts of the second limiting plate. At the same time, the fixing through holes on the second limiting plate and the first limiting plate are aligned with each other. S15: After confirming that the two outer conductors are correctly mounted in the limiting grooves of the first limiting plate and the second limiting plate, and that the inner surfaces are tightly fitted on the limiting posts of the first limiting plate and the second limiting plate, fastening rods are installed in the fixing through holes of the first limiting plate and the second limiting plate, and both ends are fastened with nuts. At the same time, nuts are additionally installed on both ends of the limiting pull rod for fastening. S16: Place the weldment and the fastener of the tooling horizontally into the welding chamber of the electron beam welder, and fasten the connecting sleeve into the welding machine chuck; after vacuuming to meet the process requirements, use the corresponding welding process to weld the outer welds of the outer conductor and the inner conductor; after welding is completed, remove the outer weld auxiliary tooling.

6. The method for welding a radio frequency superconducting cavity conductor and an outer conductor according to claim 5, characterized in that: In step S16, the following method is used when welding the outer weld of the outer conductor and the inner conductor: After the vacuum reaches the process requirements, the first spot welding method is used to spot weld the outer weld formed by the first outer conductor and the inner conductor; After spot welding is completed, the weldment and the tooling are rotated 180° by the welding machine chuck, and the second outer conductor and the outer weld of the inner conductor are spot welded first, and then the corresponding welding process is used to formally weld this weld; After welding is completed, the weldment and the tooling are rotated 180° by the welding machine chuck, and the corresponding welding process is used to formally weld the first outer conductor and the outer weld of the inner conductor.

7. The method for welding a radio frequency superconducting cavity conductor and an outer conductor according to claim 4, characterized in that: In step S2, the welding of the outer conductor and the inner weld of the inner conductor is carried out in the following manner: S21: Assemble the first pressing head and the connecting head together and fasten them together with a fixing rod to form a composite tool; S22: Fitting the outer surface of the first outer conductor of the welded body with the outer weld seam to the first pressing head in the composite tooling; clamping the second pressing head into the end of the inner conductor located at the second outer conductor, while aligning the screw hole on the second pressing head with the screw hole on the first pressing head; then inserting a fixing rod into the screw hole and tightening it with a nut to integrate the weldment with the welding tooling; S23: Clamp the connector into the chuck in the welding chamber of the electron beam welder. The chuck elevation angle of the welder is 42°. After the vacuum is evacuated to meet the process requirements, use the corresponding welding process to weld the internal welds of the outer conductor and the inner conductor. After welding is completed, remove the internal weld auxiliary tooling.

8. The method for welding a radio frequency superconducting cavity conductor and an outer conductor according to claim 7, characterized in that: In step S23, the following method is used when welding the inner seam of the outer conductor and the inner conductor: After the vacuum is exhausted to meet the process requirements, the inner weld of the inner conductor and the first outer conductor is welded according to the welding process. After welding, the inner weld of the inner conductor and the first outer conductor is removed from the furnace after meeting the furnace conditions. The inner weld of the inner conductor and the first outer conductor is completed. After rotating the weldment 180°, the end of the second outer conductor is engaged with the first pressing head, and the above steps are repeated to complete the internal weld of the inner conductor and the second outer conductor.

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