Octagonal radio frequency quadrupole acceleration cavity single-section cavity, welding device and welding method

Abstract

The invention provides an octagonal radio frequency quadrupole acceleration cavity single-section cavity, a welding device and a welding method, and relates to the technical field of accelerators. The single-section cavity adopts a four-block design, namely, the single-section cavity is configured to be composed of a first vertical electrode, a first horizontal electrode, a second vertical electrode and a second horizontal electrode; the first vertical electrode and the second vertical electrode are each provided with a protruding structure in the direction facing the interior of the cavity, in other words, the protruding structures are designed to be W-shaped, and the protruding structures are configured to serve as geometric symmetry references to ensure that in the machining process, the machining precision is improved. The degree of symmetry of the first vertical electrode and the second vertical electrode relative to the first horizontal electrode and the second horizontal electrode meets a preset condition; and one of any two contacted electrodes of the first vertical electrode, the first horizontal electrode, the second vertical electrode and the second horizontal electrode is provided with a solder groove for filling solder. Compared with a traditional eight-block type design, the single-section cavity has the advantage that the machining precision of the cavity is greatly improved.

Description

Technical Field

[0001] This disclosure relates to the field of accelerator technology, and more specifically, to an octagonal radio frequency quadrupole accelerator cavity single-segment cavity, a welding device, and a welding method. Background Technology

[0002] The Radio Frequency Quadrupole (RFQ) is the core component of a linear accelerator. Its core working principle utilizes a radio frequency electric field to generate an alternating electric field gradient within a quadrupole symmetrical electrode structure, achieving longitudinal acceleration and lateral focusing of a charged particle beam. Due to its compact structure, small size, ability to accelerate both positive and negative ions, and high acceleration efficiency, the RFQ is widely used in fields such as nuclear physics, mechanical engineering, metallurgy, medicine, and food processing.

[0003] In the production process of RFQ cavities, the welding of the cavities is crucial. Currently, the existing welding methods have the following problems: (1) Solder is prone to seepage into the cavity, which will affect the frequency of the cavity and cause high-voltage arcing during cavity operation. (2) Welding deformation exists, which directly affects the acceleration efficiency and beam acceleration quality of the cavity. (3) Failure to weld the cavity can easily lead to vacuum leakage, which directly renders the cavity unusable.

[0004] Therefore, there is an urgent need to design a new welding technology to solve the core problems of seepage welding, deformation, and vacuum leakage in the welding of octagonal RFQ cavities. Summary of the Invention

[0005] In view of this, the present disclosure provides an octagonal radio frequency quadrupole accelerating cavity single-segment cavity, a welding device, and a welding method.

[0006] One aspect of this disclosure provides an octagonal radio frequency quadrupole accelerating cavity single-segment cavity, the single-segment cavity being configured to consist of a first vertical electrode, a first horizontal electrode, a second vertical electrode, and a second horizontal electrode; wherein the first vertical electrode and the second vertical electrode are respectively provided with protrusion structures in the direction of the cavity interior, the protrusion structures being configured to serve as geometric symmetry references to ensure that the symmetry of the first vertical electrode and the second vertical electrode relative to the first horizontal electrode and the second horizontal electrode meets preset conditions during the processing; wherein, among any two contacting electrodes of the first vertical electrode, the first horizontal electrode, the second vertical electrode, and the second horizontal electrode, one of them is respectively provided with a solder groove for filling solder.

[0007] According to an embodiment of the present disclosure, the solder bath includes: an annular solder bath arrayed on the contact surface; and a straight solder bath located at the periphery of the annular solder bath.

[0008] According to embodiments of this disclosure, the solder used is a silver-copper alloy solder with a diameter of 0.8 mm to 1 mm.

[0009] According to embodiments of this disclosure, the width of the solder bath is 1 mm to 1.05 mm, and the depth of the solder bath is 1 mm to 1.5 mm.

[0010] According to embodiments of this disclosure, the solder bath is a sealed structure.

[0011] Another aspect of this disclosure provides a welding apparatus for a single segment of an octagonal radio frequency quadrupole accelerating cavity, comprising: a welding base plate for supporting the single segment cavity; side electrode adjustment plates disposed on both sides of the single segment cavity for adjusting the single segment cavity from a side position to align the side positions of the single segment cavity; end electrode adjustment plates disposed at both ends of the single segment cavity for adjusting the single segment cavity from an end face position to align the end face positions of the single segment cavity; and a lifting member disposed on the welding base plate for adjusting the distance gap between the contact surfaces of the single segment cavity.

[0012] According to embodiments of this disclosure, adjusting bolts are provided on the side electrode adjusting plate and the end electrode adjusting plate, wherein the positions of the side electrode adjusting plate and the end electrode adjusting plate can be controlled by adjusting the adjusting bolts.

[0013] According to an embodiment of this disclosure, the lifting component includes: a cavity tensioning rod disposed on a welded base plate; a top pressure plate connected to the cavity tensioning rod; and a disc spring sleeved on the cavity tensioning rod, wherein the position of the top pressure plate can be adjusted by controlling the deformation of the disc spring.

[0014] According to embodiments of this disclosure, the welding apparatus is made of 304 stainless steel.

[0015] Another aspect of this disclosure provides a method for welding a single-segment cavity of an octagonal radio frequency quadrupole accelerating cavity, comprising: hoisting the single-segment cavity assembled using a welding device into the homogenization zone of a hydrogen furnace; preheating the single-segment cavity, wherein, in the preheating stage, the preheating time is 2 hours and the heating rate is 2℃ / min; rapidly heating the preheated single-segment cavity, wherein, in the rapid heating stage, the rapid heating time is 1 hour and the heating rate is 3℃ / min, until the temperature uniformly rises to 780℃; and performing a first heat preservation treatment on the rapidly heated single-segment cavity, wherein, in the first heat preservation stage, the heat preservation... The process takes 1 hour. The single-section cavity after the first heat preservation treatment undergoes a slow heating process, with a heating rate of 1℃ / min for 1 hour, until the temperature uniformly rises to 840℃. The single-section cavity after the slow heating treatment undergoes a second heat preservation treatment, with a holding time of 0.2 hours. The single-section cavity after the second heat preservation treatment undergoes a cooling process, with a rapid cooling rate of 5℃ / min until the temperature uniformly drops to 600℃, followed by a 0.5-hour heat preservation period before cooling with the furnace to room temperature.

[0016] Compared with the prior art, the octagonal radio frequency quadrupole accelerating cavity single-segment cavity, welding device and welding method provided in this disclosure have at least the following beneficial effects:

[0017] (1) The octagonal radio frequency quadrupole accelerating cavity single-segment cavity provided in this disclosure adopts a four-block design, that is, it is divided into two vertical electrodes and two horizontal electrodes. Among them, the two vertical electrodes adopt a "W-shaped" structure design to ensure the symmetry of their electrode heads relative to the two wings. Compared with the traditional eight-block design, it greatly improves the assembly accuracy and assembly efficiency of the cavity.

[0018] (2) The octagonal radio frequency quadrupole accelerator cavity single-segment cavity provided in this disclosure has a solder groove designed on the horizontal contact surface and adopts a sealed design, which effectively prevents solder leakage and avoids high-voltage arcing during cavity operation.

[0019] (3) The octagonal radio frequency quadrupole accelerating cavity single-segment cavity welding device provided in this disclosure can be reused, thus effectively improving assembly efficiency with a small production cost. Attached Figure Description

[0020] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0021] Figure 1 A schematic cross-sectional view of a single segment of an octagonal radio frequency quadrupole accelerating cavity according to an embodiment of the present disclosure is shown.

[0022] Figure 2 A schematic diagram of a solder bath according to an embodiment of the present disclosure is shown.

[0023] Figure 3 A schematic diagram of a single-segment cavity welding apparatus for an octagonal radio frequency quadrupole accelerating cavity according to an embodiment of the present disclosure is shown.

[0024] Figure 4 The diagram schematically illustrates the effect of an assembled single-segment cavity according to an embodiment of the present disclosure.

[0025] Figure label:

[0026] 1-Welding base plate; 2-Side electrode adjusting plate; 3-End electrode adjusting plate; 4-Lifting component; 41-Cavity tension rod; 42-Top pressure plate; 43-Disc spring; 44-Fixing nut; 5-Adjusting bolt; 6-Fixing bolt. Detailed Implementation

[0027] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0029] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0030] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0031] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0032] Figure 1 A schematic cross-sectional view of a single segment of an octagonal radio frequency quadrupole accelerating cavity according to an embodiment of the present disclosure is shown.

[0033] like Figure 1 As shown, the single-segment cavity in this embodiment adopts a four-block design, specifically, it is configured to consist of a first vertical electrode, a first horizontal electrode, a second vertical electrode, and a second horizontal electrode.

[0034] from Figure 1 From the directions shown, the first vertical electrode is the upper vertical electrode, the second vertical electrode is the lower vertical electrode, the first horizontal electrode is the left horizontal electrode, and the second horizontal electrode is the right horizontal electrode.

[0035] The first vertical electrode and the second vertical electrode are respectively provided with protruding structures in the direction of the cavity interior. The protruding structures are configured to serve as geometric symmetry references to ensure that the symmetry of the first vertical electrode and the second vertical electrode relative to the first horizontal electrode and the second horizontal electrode meets preset conditions during the processing.

[0036] For example, in an embodiment of this disclosure, the first vertical electrode and the second vertical electrode are designed as a "W-shaped" structure with a raised structure.

[0037] The W-shaped structure design gives the upper and lower vertical electrodes a built-in geometric symmetry reference, making it easier to ensure the symmetrical position and consistent contour of the electrode head during processing, thereby guaranteeing the accuracy of the geometry of the entire RFQ cavity.

[0038] Of the first vertical electrode, the first horizontal electrode, the second vertical electrode, and the second horizontal electrode, one of any two electrodes in contact is provided with a solder trough for filling solder.

[0039] For example, in embodiments of this disclosure, from Figure 1 From the indicated direction, the solder trough can be positioned on the contact surface with the lower vertical electrode facing upwards, as well as on the contact surfaces with the left and right horizontal electrodes facing upwards. If the single-segment cavity is flipped upside down, the position of the solder trough also needs to be changed to the opposite side accordingly. In summary, in this embodiment of the present disclosure, when the single-segment cavity is placed horizontally, the solder trough is always positioned with the contact surface facing upwards to ensure easy solder assembly and prevent solder from flowing out.

[0040] The octagonal radio frequency quadrupole accelerating cavity single-segment cavity disclosed herein adopts a four-block design, namely, it is divided into two vertical electrodes and two horizontal electrodes. Among them, the two vertical electrodes adopt a "W-shaped" structure design to ensure the symmetry of their electrode heads relative to the two wings. Compared with the traditional eight-block design, it greatly improves the assembly accuracy and assembly efficiency of the cavity.

[0041] In this embodiment of the disclosure, the solder bath includes: an annular solder bath and a straight solder bath.

[0042] The annular solder groove array is distributed on the contact surface, and the straight solder groove is located on the periphery of the annular solder groove, as detailed below. Figure 2 As shown.

[0043] Figure 2 A schematic diagram of a solder bath according to an embodiment of the present disclosure is shown.

[0044] like Figure 2 As shown, the solder bath in this embodiment is divided into annular solder bath and straight solder bath. The annular solder bath is distributed around the bolt connection hole, and the straight solder bath forms a "surrounding ring" around the annular solder bath.

[0045] In this embodiment of the disclosure, the solder used is a silver-copper alloy solder with a diameter of 0.8 mm to 1 mm. For example, during pre-soldering assembly, AgCu28 solder with a diameter of φ=1 mm can be filled into the solder bath.

[0046] In this embodiment, the width of the solder bath is 1mm to 1.05mm, and the depth of the solder bath is 1mm to 1.5mm. For example, preferably, the width of the solder bath can be designed to be 1.04mm, and the depth can be designed to be 1.3mm.

[0047] The total volume after the solder filling must meet the solder requirements of the welding surface. The design of the annular solder groove can ensure the vacuum sealing around the bolt holes after welding.

[0048] In addition, to ensure welding results, all solder tanks are sealed and the welding surfaces are placed horizontally, which ensures that the solder does not fall out and reduces assembly difficulty.

[0049] The octagonal radio frequency quadrupole accelerating cavity single-segment cavity disclosed herein has a solder groove designed on the horizontal contact surface and adopts a sealed design, which effectively prevents solder leakage and avoids high-voltage arcing during cavity operation.

[0050] This disclosure also provides an octagonal radio frequency quadrupole accelerating cavity single-segment cavity welding device, see details below. Figure 3 As shown.

[0051] Figure 3The schematic diagram illustrates the structure of an octagonal radio frequency quadrupole accelerating cavity single-segment cavity welding apparatus according to an embodiment of the present disclosure.

[0052] like Figure 3 As shown, the welding apparatus of this embodiment may include, for example, a welding base plate 1, a side electrode adjusting plate 2, an end electrode adjusting plate 3, and a lifting component 4.

[0053] The welding base plate 1 is used to support the single-section cavity.

[0054] The side electrode adjustment plate 2 is located on both sides of the single-segment cavity and is used to adjust the single-segment cavity from the side position so that the side positions of the single-segment cavity can be aligned. For example, a single electrode can be adjusted from both sides to align the two sides of the single-segment cavity.

[0055] The end electrode adjustment plate 3 is located at both ends of the single-segment cavity and is used to adjust the single-segment cavity from its end face position so that the end face positions of the single-segment cavity can be aligned. For example, a single electrode can be adjusted from both ends to align the two ends of the single-segment cavity.

[0056] The lifting component 4 is mounted on the welding base plate 1 and is used to adjust the distance gap between the contact surfaces of the single-section cavity.

[0057] In this embodiment, the side electrode adjusting plate 2 and the end electrode adjusting plate 3 are respectively provided with adjusting bolts 5, wherein the positions of the side electrode adjusting plate 2 and the end electrode adjusting plate 3 can be controlled by adjusting the adjusting bolts 5. In addition, the side electrode adjusting plate 2 is also provided with fixing bolts 6 for fixing the electrode.

[0058] In this embodiment, the lifting member 4 may further include: a cavity tensioning rod 41, a top pressure plate 42, and a disc spring 43.

[0059] The tensioning rod 42 of the cavity is located on the welding base plate 1.

[0060] The top pressure plate 42 is connected to the cavity tension rod 41.

[0061] The disc spring 43 is sleeved on the cavity tension rod 41. The clamping force of the top pressure plate 42 can be adjusted by controlling the deformation of the disc spring 43.

[0062] For example, in this embodiment of the disclosure, the deformation of the disc spring 43 can be controlled by fitting a fixing nut 44 onto the disc spring 43, thereby adjusting the clamping force of the top pressure plate 42.

[0063] In this embodiment of the disclosure, all structures in the welding apparatus are made of 304 stainless steel.

[0064] Based on this welding device, the pre-assembly process for a single-section cavity is as follows:

[0065] First, place the lower vertical electrode on the welding base plate 1, then hoist and place the left and right horizontal electrodes, and finally hoist and place the upper vertical electrode.

[0066] After the electrodes are placed, install the side electrode adjustment plate 2, the end electrode adjustment plate 3, the cavity tension rod 41, and the disc spring 43 respectively.

[0067] The horizontal electrodes are finely adjusted using the adjusting bolts on the side electrode adjusting plate 2, and the end faces of the four electrodes are aligned using the adjusting bolts on the end electrode adjusting plate 3. The gap at the electrode welding surfaces is controlled to be below 0.03mm using the cavity tension rod 41, disc spring 43, top pressure plate 42, and fixing nut 44. During pre-assembly, an articulated arm measuring instrument can be used to measure the internal cavity dimensions and electrode head symmetry in real time. If the required dimensions cannot be achieved, the cause of the error is analyzed, and individual electrodes are fine-tuned before reassembly and testing are repeated until the electrode head symmetry and internal cavity dimensions meet the physical design requirements.

[0068] After the cavity is pre-rotated, the electrode connecting bolts are installed and tightened, and the entire assembly is hoisted. The conical pin holes are then fitted and the conical pins are installed. Finally, the cavity is disassembled and the electrodes are cleaned. This welding device is reusable, effectively improving assembly efficiency with minimal production cost.

[0069] The pre-welding assembly process for a single-section cavity is as follows:

[0070] Perform a visual inspection on the cleaned electrodes to ensure that the welding surfaces and electrode tips are free from dents and scratches. Fill the solder tank with φ1mm AgCu28 solder. Place the lower vertical electrode on the welding base plate 1, followed by the left and right horizontal electrodes and the upper vertical electrode in sequence. Reset the electrodes using the conical pins and tighten the electrode connecting screws (which mate with the electrode connecting bolts). Install the cavity tension rod 41, disc spring 43, top pressure plate 42, and fixing nut 44. Re-measure the internal cavity dimensions, electrode tip symmetry, and welding surface gap. The cavity is placed horizontally during welding. See details below. Figure 4 As shown.

[0071] Figure 4 The diagram schematically illustrates the effect of an assembled single-segment cavity according to an embodiment of the present disclosure.

[0072] like Figure 4 As shown, the assembled single-section cavity is placed horizontally. Due to the sealed design of the solder bath and the horizontal placement of the welding surface, it can be ensured that no solder seeps out of the RFQ cavity.

[0073] During assembly, it is important to note that the connection between the welding base plate 1 and the cavity tension rod 41, as well as the surface of the disc spring 43, must be coated with boron nitride to prevent adhesion after welding and ensure that the welding fixture can be reused. During welding, the top pressure plate 42, in conjunction with the disc spring 43, can achieve a welding surface gap of less than 0.03mm. In addition, the use of the disc spring 43 can avoid rigid electrode connection and reduce welding deformation.

[0074] This disclosure also provides a method for welding a single segment of an octagonal radio frequency quadrupole accelerating cavity, which may include, for example:

[0075] S1, the single-section cavity assembled using the welding device is hoisted into the homogenization zone of the hydrogen furnace.

[0076] S2, preheating treatment of the single-section cavity, wherein the preheating time is 2 hours and the heating rate is 2℃ / min.

[0077] S3 involves rapidly heating the preheated single-section cavity. During the rapid heating phase, the heating time is 1 hour and the heating rate is 3℃ / min, until the temperature rises uniformly to 780℃.

[0078] S4, the single-section cavity after rapid heating is subjected to the first heat preservation treatment, wherein the heat preservation time in the first heat preservation stage is 1 hour.

[0079] S5. The single-section cavity after the first heat preservation treatment is slowly heated. During the slow heating stage, the slow heating time is 1 hour and the heating rate is 1℃ / min until the temperature rises uniformly to 840℃.

[0080] S6, the single-section cavity after slow heating is subjected to a second heat preservation treatment, wherein the heat preservation time in the second heat preservation stage is 0.2 hours.

[0081] S7. The single-section cavity after the second heat preservation treatment is cooled down. In the cooling stage, rapid cooling is first performed at a rate of 5℃ / min until the temperature drops uniformly to 600℃. Then, it is kept at the heat for 0.5 hours and then cooled down with the furnace until room temperature.

[0082] In this embodiment of the disclosure, the cavity welding process includes six stages: preheating, rapid heating, first heat preservation, slow heating, second heat preservation, and cooling. For example:

[0083] Before welding, assemble all the required single-section cavities and then hoist them as a whole into the hydrogen furnace for welding. The welding assembly must be placed in the welding homogenization zone of the hydrogen furnace. Temperature probes are fixed at both ends and in the middle of the cavity for real-time monitoring of the welding temperature.

[0084] The six stages—preheating, rapid heating, first heat preservation, slow heating, second heat preservation, and cooling—are as follows:

[0085] Preheating stage: The heating time is controlled within 2 hours, and the heating rate is controlled at 2℃ / min; Rapid heating stage: From the 2nd to the 5th hour, the heating rate is controlled at 3℃ / min until the temperature rises uniformly to 780℃; First holding stage: In this stage, the temperature is maintained for 1 hour; Slow heating stage: From the 6th to the 7th hour, the heating rate is controlled at 1℃ / min until the temperature rises uniformly to 840℃; Second holding stage: In this stage, the temperature is maintained for 0.2 hours; Cooling stage: First, the temperature is rapidly reduced at a rate of 5℃ / min until the temperature drops uniformly to 600℃, and then held for 0.5 hours before cooling with the furnace to room temperature.

[0086] During the above welding process, the heating and cooling rates must be uniform, and the temperature of different parts of the cavity must be monitored throughout the process for flexible adjustments. Furthermore, the welded parts must be allowed to cool to room temperature before being removed from the furnace to prevent oxidation of the cavity and its impact on weld quality. Using this welding method effectively ensures weld quality and improves the success rate of cavity welding.

[0087] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions. Those skilled in the art will understand that the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways, even if such combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments of this disclosure may be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0088] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. An octagonal radio frequency quadrupole accelerating cavity single-segment cavity, characterized in that, The single-segment cavity is configured to consist of a first vertical electrode, a first horizontal electrode, a second vertical electrode, and a second horizontal electrode. The first vertical electrode and the second vertical electrode are respectively provided with protruding structures in the direction of the cavity interior. The protruding structures are configured to serve as geometric symmetry references to ensure that the symmetry of the first vertical electrode and the second vertical electrode relative to the first horizontal electrode and the second horizontal electrode meets preset conditions during the processing. Among the first vertical electrode, the first horizontal electrode, the second vertical electrode, and the second horizontal electrode, one of any two electrodes in contact is provided with a solder trough for filling solder.

2. The single-segment cavity according to claim 1, characterized in that, The solder bath includes: An annular solder groove is arrayed on the contact surface; A straight solder trough is located at the outer periphery of the annular solder trough.

3. The single-segment cavity according to claim 2, characterized in that, The solder used is a silver-copper alloy solder with a diameter of 0.8 mm to 1 mm.

4. The single-segment cavity according to claim 2, characterized in that, The width of the solder trough is 1mm to 1.05mm, and the depth of the solder trough is 1mm to 1.5mm.

5. The single-segment cavity according to claim 2, characterized in that, The solder bath is a sealed structure.

6. An octagonal radio frequency quadrupole accelerating cavity single-segment cavity welding device, applied to the single-segment cavity as described in any one of claims 1 to 5, characterized in that, The welding apparatus includes: A welded base plate is used to support the single-section cavity; Side electrode adjustment plates are disposed on both sides of the single-segment cavity and are used to adjust the single-segment cavity from the side position so that the side positions of the single-segment cavity can be aligned. An end electrode adjustment plate is disposed at both ends of the single-segment cavity and is used to adjust the single-segment cavity from the end face position so that the end face positions of the single-segment cavity can be aligned. A lifting component, located on the welding base plate, is used to adjust the distance gap between the contact surfaces of the single-segment cavity.

7. The welding apparatus according to claim 6, characterized in that, The side electrode adjusting plate and the end electrode adjusting plate are respectively provided with adjusting bolts, wherein the positions of the side electrode adjusting plate and the end electrode adjusting plate can be controlled by adjusting the adjusting bolts.

8. The welding apparatus according to claim 6, characterized in that, The lifting component includes: A cavity tensioning rod is provided on the welding base plate; The top pressure plate is connected to the cavity tension rod; A disc spring is sleeved on the tension rod of the cavity, wherein the disc spring is controlled by... The deformation of the spring can adjust the position of the top pressure plate.

9. The welding apparatus according to claim 6, characterized in that, The welding device is made of 304 stainless steel.

10. A method for welding a single-segment cavity of an octagonal radio frequency quadrupole accelerating cavity, applied to the welding apparatus as described in any one of claims 6 to 9, characterized in that, The welding method includes: The single-section cavity assembled using the welding device is hoisted into the homogenization zone of the hydrogen furnace. The single-section cavity is preheated, wherein the preheating time is 2 hours and the heating rate is 2℃ / min. The preheated single-section cavity is subjected to rapid heating treatment. During the rapid heating stage, the rapid heating time is 1 hour and the heating rate is 3℃ / min until the temperature rises uniformly to 780℃. The single-section cavity after rapid heating is subjected to a first heat preservation treatment, wherein the heat preservation time in the first heat preservation stage is 1 hour; The single-section cavity after the first heat preservation treatment is subjected to slow heating treatment. During the slow heating stage, the slow heating time is 1 hour and the heating rate is 1℃ / min until the temperature rises uniformly to 840℃. The single-section cavity after slow heating is subjected to a second heat preservation treatment, wherein the heat preservation time in the second heat preservation stage is 0.2 hours; The single-section cavity after the second heat preservation treatment is subjected to a cooling treatment. In the cooling stage, rapid cooling is first performed at a rate of 5℃ / min until the temperature drops uniformly to 600℃. Then, it is kept at the heat for 0.5 hours and then cooled with the furnace until room temperature.

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