CN109874222B - Drift tube, drift tube linear accelerator and drift tube processing method - Google Patents

Abstract

The invention provides a drift tube, a drift tube linear accelerator and a drift tube processing method. The drift tube body and the drift tube end cover are in threaded connection, so that the permanent magnet quadrupole magnet can be arranged after the support rod is machined when the drift tube is machined, the overall dimension of the drift tube body is repaired and the permanent magnet quadrupole magnet is assembled by taking the support rod as a reference, the machining difficulty of the drift tube body is reduced, the permanent magnet quadrupole magnet assembly precision is higher, the magnetism measuring times are effectively reduced, the machining of the drift tube is simpler, the cost is lower, the precision is higher, and the reliability of the drift tube and the overall yield of machined parts are improved.

Description

A drift tube, a drift tube linear accelerator, and a method for manufacturing a drift tube

technical field

The invention relates to the technical field of linear accelerators, in particular to a drift tube, a drift tube linear accelerator including the drift tube, and a processing method of the drift tube.

Background technique

In the prior art, the connection between the main body of the drift tube and the end cap is electron beam welding. Due to the structure of the drift tube itself, the welding seam between the main body and the end cap of the drift tube is within the projection range of the support rod. , the electron beam will be blocked by the support rod, which leads to the existing drift tube basically welding the end cap first, and then welding the support rod. The processing difficulty caused by this processing sequence is as follows:

1. The magnet should be installed into the main body of the drift tube before welding the end cap. Due to the reason of the magnet, cutting fluid cannot be used during the machining process, which makes it difficult to process the overall shape of the drift tube, and it is difficult to meet the requirements of smoothness;

2. First install the magnet and fix the main body and end cover of the drift tube by welding, and then process the support rod with the completed assembly as the benchmark. Due to the small size of the alignment benchmark, when using the small benchmark to process distant entities, in order to ensure the size and tolerances, it is necessary to process precision tooling during the processing process, and strictly control the processing parameters, which makes the processing difficult.

Therefore, the overall machining accuracy of the existing drift tube is decreased and the machining cost is increased.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a drift tube with simpler processing, lower cost and higher precision.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical solutions:

The present invention provides a drift tube, comprising: a drift tube body assembly and a drift tube end cap, the drift tube body assembly includes a drift tube body, the drift tube end cap is fixed at one end of the drift tube body, and the drift tube end cap is fixed at one end of the drift tube body. One end of the drift tube main body is threadedly connected with the drift tube end cap.

The drift tube provided in this embodiment includes a drift tube body assembly and a drift tube end cover. The drift tube body assembly includes a cylindrical drift tube body, and the drift tube end cover is fixed at one end of the drift tube body. The shape and size of the end cap of the drift tube are matched with the main body of the drift tube, the outer wall of one end of the main body of the drift tube is provided with an external thread, and the end cap of the drift tube is provided with an inner thread on the inner wall of the end that matches the main body of the drift tube. , The main body of the drift tube and the end cap of the drift tube are connected by threads, so that the main body of the drift tube and the end cap of the drift tube are coaxial and tightly matched.

In this embodiment, the drift tube end cap and the drift tube main body are connected by threads, which eliminates the electron beam welding fixing method between the drift tube main body and the drift tube end cap in the prior art, and simplifies the drift tube processing procedure. The number of magnetic measurements is reduced, and the processing difficulty of the drift tube is greatly reduced. In addition, compared with the prior art, the thread connection processing process in this embodiment is simple and fast, and the deformation is small, which avoids the welding deformation repair process, welding seam area defects and the interference of the internal magnet to the welding process during the welding process, and improves the efficiency of the welding process. The connection reliability and processing efficiency of the drift tube reduce processing costs and improve the overall yield of processed parts.

Optionally, the drift tube further includes a permanent magnet quadrupole magnet, the drift tube main body has a accommodating cavity, the permanent magnet quadrupole magnet is arranged in the accommodating cavity, and a pressure ring is fixed in the accommodating cavity, The pressing ring presses and fixes the permanent magnet quadrupole magnet on the cavity wall at the end of the accommodating cavity away from the end cover of the drift tube.

The main body of the drift tube has a hollow cylindrical accommodating cavity, and a permanent magnet quadrupole magnet is arranged in the accommodating cavity, and the permanent magnet quadrupole magnet is used for focusing the particle beam passing through the drift tube. There is also an annular pressure ring in the main body of the drift tube. The pressure ring is fixed on the cavity wall of the accommodating cavity. Through the pressure ring, the permanent magnet quadrupole magnet (the outer shell of which is provided with a metal magnet skeleton) can be pressed and fixed on the far away drift of the accommodating cavity. The cavity wall at one end of the tube end cover ensures that the permanent magnet quadrupole magnet does not slide in the direction of the central axis of the accommodating cavity.

Compared with the existing permanent magnet quadrupole magnet in the drift tube, the permanent magnet quadrupole magnet is pressed and fixed on the end cover of the drift tube by means of springs and pressing sheets. In this embodiment, a pressing ring is installed in the accommodating cavity, so that the pressing ring locks the magnet. The skeleton is directly fixed in the accommodating cavity, so that the permanent magnet quadrupole magnet is fixed on the main body of the drift tube, so that there is no direct connection between the pressure ring and the end cap of the drift tube, and the thread between the end cap of the drift tube and the main body of the drift tube is avoided. After the connection, the thread of the drift tube end cap is retracted due to the reaction force of the pressure magnet acting on the drift tube end cap, which fully guarantees the reliability of the threaded connection between the drift tube body and the drift tube end cap.

Optionally, the pressure ring is threadedly connected to the cavity wall of the accommodating cavity.

The pressure ring is annular, with an outer thread on the outer wall and an inner thread on the inner wall of the accommodating cavity. The permanent magnet quadrupole magnet is pressed and fixed on the cavity wall at the end of the accommodating cavity away from the end cap of the drift tube.

Optionally, a threaded hole is provided on the pressing ring, and a fastening screw passes through the threaded hole and presses the permanent magnet quadrupole magnet.

A threaded hole is arranged on the pressure ring, and the permanent magnet quadrupole magnet is pressed by the fastening screw after passing through the threaded hole. Specifically, during assembly, the permanent magnet quadrupole magnet is first put into the hollow accommodating cavity in the main body of the drift tube; then the pressure ring is placed in the accommodating cavity, and the outer thread on the outer wall of the pressure ring is connected to the cavity of the accommodating cavity. The inner thread on the inner wall is fixed with each other, and the permanent magnet quadrupole magnet is pressed and fixed on the cavity wall at the end of the accommodating cavity away from the end cover of the drift tube through the pressure ring; finally, the fastening screw passes through the thread on the pressure ring. The hole further locks and fixes the metal magnet skeleton (ie, the permanent magnet quadrupole magnet) in the accommodating cavity of the drift tube main body.

Optionally, the drift tube further includes a support rod, and the support rod and the main assembly of the drift tube are fixed by electron beam welding.

The drift tube of this embodiment further includes a support rod, the support rod is a hollow cylindrical shape, a water separation column is welded on the main body of the drift tube, and the support rod is fixed on the upper end of the water separation column by electron beam welding. Specifically, firstly, the lower end of the water separation column is fixed on the cylindrical outer wall surface of the drift tube main body by electron beam welding, and then the lower end of the support rod and the upper end of the water separation column are connected by electron beam welding, that is, the support rod is located in the water separation column. the upper end, so as to achieve the purpose of fixing the support rod and the main assembly of the drift tube.

The existing drift tubes all need to be aligned with the whole body of the drift tube equipped with the permanent magnet quadrupole magnet and the end cap of the drift tube as the benchmark to process the support rod. At this time, the alignment benchmark size is small, and the tooling requirements are high during the processing process. Processing is difficult. The technical solution provided in this embodiment can weld and fix the support rod before the permanent magnet quadrupole magnet is assembled and the drift tube main body and the drift tube end cover are connected, which can not only avoid the interference of the permanent magnet quadrupole magnet to the welding process, but also can improve the efficiency of the welding process. The large support rod body is aligned to process and assemble the permanent magnet quadrupole magnet, the main body of the drift tube and the end cover of the drift tube, so that the machining accuracy of the support rod, the permanent magnet quadrupole magnet, the main body of the drift tube and the end cover of the drift tube is the same. The assembly precision is improved, and the processing and assembly process is simpler, which is beneficial to reduce the processing cost and improve the processing efficiency.

Optionally, cutting fluid is used in the process of modifying the shapes of the drift tube main body, the support rod, the water jacket and the water separation column before installing the permanent magnet quadrupole magnet.

In this embodiment, before installing the permanent magnet quadrupole magnet, it is necessary to weld and fix the water separation column, the support rod, the water jacket and the main body of the drift tube, and to repair the shape. Cooling and chip removal, so that the central axis of the support rod and the central axis of the water separation column are collinear, and the central axis of the support rod and the central axis of the drift tube main body are perpendicularly intersected; then the central axis of the accommodating cavity in the drift tube main body is aligned with the drift tube. The central axis of the tube body is collinear, so that the central axis of the support rod and the central axis of the accommodating cavity in the drift tube body are perpendicularly intersected.

Compared with the prior art, this embodiment adopts the processing sequence of welding the support rods and then loading the permanent magnet quadrupole magnets, so cutting fluid can be used to better control the welding and repairing processes without magnets. The roughness of the workpiece is reduced, the welding deformation is reduced, the machining accuracy of the drift tube is improved, and the interference of the cutting fluid on the internal magnet is avoided.

The present invention also provides a drift tube linear accelerator comprising the drift tube described above.

The invention provides a drift tube linear accelerator including the above drift tube. By adopting the threaded connection between the drift tube main body and the drift tube end cover, the component structure and processing sequence of the drift tube linear accelerator are improved, so that the permanent magnet quadrupole magnet is used. The mechanical structure of the drift tube linear accelerator is simplified, and the difficulty of processing and assembly is reduced, which fully guarantees the various indicators of the drift tube linear accelerator.

The present invention also provides a method for processing the drift tube, comprising:

1. Preliminarily process the drift tube body and the drift tube end cap, retain the machining allowance, and fix the drift tube body with the water jacket and the water separation column to obtain the drift tube body assembly;

Specifically, firstly, the cylindrical outer circle and the cylindrical inner cavity of the drift tube main body and the drift tube end cover are preliminarily processed, and the machining allowance is reserved; The processing of the first through hole and the second through hole on the far away ends of the drift tube body and the drift tube end cap, the internal thread on the inner side wall of the drift tube end cap and the cylindrical outer wall of the drift tube body. The processing of the installation groove; then, the water jacket is fixed on the inner side wall of the drift tube main body by electron beam welding to form a hollow cylindrical accommodating cavity, and the water separation column is vertically fixed in the installation groove on the drift tube main body by electron beam welding, To preliminarily complete the processing of the drift tube main assembly;

2. Preliminarily process the support rod, retain the machining allowance, and fix the support rod on the water separation column by electron beam welding;

Specifically, the outer shape and inner cavity of the support rod are preliminarily processed, and the machining allowance is reserved; then the support rod is vertically fixed on the upper end of the water separation column by electron beam welding;

3. Repair the support rod, the water separation column, the drift tube body and the water jacket, so that the central axis of the support rod and the central axis of the water separation column are collinear, and the center of the support rod the axis perpendicularly intersects with the central axis of the drift tube main body, and the central axis of the accommodating cavity in the drift tube main body is collinear with the central axis of the drift tube main body;

Specifically, firstly, according to the welding deformation, the shape and inner diameter of the support rod and the water-dividing column are modified so that the central axis of the support rod and the central axis of the water-dividing column are collinear; then, the main body of the drift tube is modified based on the support rod The central axis of the support rod intersects vertically with the central axis of the drift tube main body, that is, the central axis of the support rod and the central axis of the water splitting column are both perpendicularly intersected with the central axis of the drift tube main body;

Then, based on the center axis of the drift tube body, the inner diameter of the water jacket in the drift tube body is modified so that the center axis of the accommodating cavity is collinear with the center axis of the drift tube body, and the center axis of the support rod is aligned with the accommodating cavity. The center axis of the drift tube intersects vertically, so as to ensure that the intersection point of the center axis of the support rod and the center axis of the accommodating cavity falls within the required range of the geometric center coordinates of the drift tube body, and preliminarily achieves the shape and shape of the drift tube body, the water separation column and the support rod. Dimensional and tolerance requirements for inside diameters. The technical solution provided in this embodiment can weld and repair the support rod before the permanent magnet quadrupole magnet is assembled and the drift tube body and the drift tube end cover are connected, which can not only prevent the internal magnet from interfering with the welding process, but also can be used in the process. Cutting fluid is used in the process to better control the roughness of the workpiece, reduce welding deformation, and improve the machining accuracy of the drift tube;

4. Detect the air tightness of the connection structure of the support rod, the water separation column, the drift tube main body and the water jacket, so as to ensure that there is no leakage inside the connection structure and the welding connection area;

Perform vacuum inspection on the connection structure of the completed support rod, water separation column, drift tube main body and water jacket in advance to ensure that the completed connection structure is complete and airtight, improve the overall yield of processed parts, and reduce repair costs;

5. Assembling the permanent magnet quadrupole magnet in the accommodating cavity in the main body of the drift tube;

The permanent magnet quadrupole magnet is pressed and fixed on the cavity wall at the end of the accommodating cavity away from the end cover of the drift tube through the pressure ring. There is no direct connection between the pressure ring and the end cap of the drift tube, which avoids the reaction force of the pressure magnet acting on the end cap of the drift tube after the end cap of the drift tube and the body of the drift tube are threadedly connected. The situation that leads to the thread back of the drift tube end cap fully guarantees the reliability of the threaded connection between the drift tube body and the drift tube end cap; in addition, in this embodiment, the support rod is first machined and then the permanent magnet quadrupole magnet is installed. , to assemble the permanent magnet quadrupole magnet based on the support rod, so that the assembly precision of the permanent magnet quadrupole magnet is higher, and the data error of the magnetic center is reduced;

6. Process external threads on the drift tube main body, and connect the drift tube main body and the drift tube end cap with threads;

The main body of the drift tube and the end cap of the drift tube are threadedly connected with a constant torque, the connection process is simple and fast, and the deformation is small, which simplifies the processing procedure of the drift tube and reduces the processing difficulty of the drift tube;

7. Use a vibrating wire magnetic center measuring device and method for a fixed magnet to measure the magnetic center coordinates of a permanent magnet quadrupole magnet to ensure that the magnetic center coordinates of the permanent magnet quadrupole magnet fall on the geometric center of the drift tube main body The coordinates (referring to the geometric center coordinates measured according to the outer circle of the drift tube main body) are within the required range (that is, the space range of a three-dimensional sphere with the geometric center coordinates of the drift tube main body as the center and the required value as the radius), satisfying Accuracy requirements of magnetic center data;

8. Take the main body of the drift tube and the support rod as the benchmark for comprehensive alignment, refer to the magnetic center data (magnetic center coordinates), and finish machining the support rod and the water separation column in place to ensure that the support rod and the The central axis of the water-dividing column passes through the magnetic center (referring to the central axis of the support rod and the water-dividing column passing through the space range of a three-dimensional sphere with the magnetic center coordinate as the center and the required value as the radius), and the support rod and the water-dividing column The size meets the requirements;

9. Align with the support rod as a reference, and finish machining the drift tube body and the drift tube end cover, so that the drift tube body and the drift tube end cover meet the size and finish requirements.

Specifically, the end faces of the drift tube main body and the drift tube end caps that are far away from each other are processed into tapered surfaces, and aligned with the support rod as a reference, and the drift tube main body and the drift tube end caps are precision machined (for example, the drift tube The outer side wall surface, inclined surface, fillet, first through hole and second through hole of the main body and the drift tube end cover are finished) to ensure the smoothness and improve the machining accuracy of the drift tube.

Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

1. The threaded connection between the main body of the drift tube and the end cap of the drift tube simplifies the processing procedure of the drift tube, reduces the number of magnetic measurements, and reduces the processing difficulty of the drift tube; in addition, the threaded connection process is simple and fast, and the deformation is small. It avoids the welding deformation repair process in the welding process, the defects of the welding seam area and the interference of the internal magnet to the welding process;

2. The permanent magnet quadrupole magnet is stably fixed in the accommodating cavity in the main body of the drift tube by the pressure ring, so that the pressure ring and the end cover are not directly connected, so as to avoid the reaction force of the pressure magnet acting on the end cover of the drift tube and causing its thread Back, improve the reliability of threaded connection;

3. This embodiment provides the processing sequence of welding the support rods first and then loading the permanent magnet quadrupole magnets. Based on the support rods, the dimensions of the drift tube are modified and the permanent magnet quadrupole magnets are assembled, so that the processing difficulty of the drift tube is reduced. The permanent magnet quadrupole magnet has higher assembly accuracy; in addition, there is no magnet in the welding process of the support rod, and cutting fluid can be used to improve the smoothness of the workpiece;

4. The processing method of the drift tube provided in this embodiment only requires one magnetic measurement. Compared with at least 4 magnetic measurement procedures in the prior art, the number of magnetic measurements is effectively reduced, the processing flow is simplified, and the processing efficiency of the drift tube is improved. ;

5. The connection structure can be vacuum tested in advance before the magnet is assembled to ensure that the completed connection structure is complete and airtight, and the yield of processed parts is improved;

6. The drift tube is easy to maintain. It only needs to remove the drift tube end cap to replace the drift tube end cap or magnet.

Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the description, claims and drawings.

Description of drawings

The accompanying drawings are used to provide a further understanding of the technical solutions of the present invention, and constitute a part of the specification. They are used to explain the technical solutions of the present invention together with the embodiments of the present application, and do not limit the technical solutions of the present invention.

1 is a schematic three-dimensional structure diagram of a drift tube according to an embodiment of the present invention;

Fig. 2 is a cross-sectional structural schematic diagram of the drift tube shown in Fig. 1;

FIG. 3 is an enlarged schematic view of the structure of part A of the drift tube shown in FIG. 2;

FIG. 4 is a perspective view of the main body assembly of the drift tube in FIG. 1;

FIG. 5 is a schematic cross-sectional view of the main body assembly of the drift tube in FIG. 4;

Fig. 6 is the three-dimensional structure schematic diagram of the drift tube end cap in Fig. 2;

Fig. 7 is the sectional structure schematic diagram of the drift tube end cap in Fig. 6;

Fig. 8 is the structural representation of the pressure ring in Fig. 2;

FIG. 9 is a schematic cross-sectional structural diagram of the pressure ring in FIG. 8 .

Among them, the relationship between the reference numerals and the component names in Figures 1-9 is:

1 support rod, 2 water separation column, 3 drift tube body, 31 first through hole, 4 drift tube end cap, 41 second through hole, 42 annular flange, 5 water jacket, 6 permanent magnet quadrupole magnet, 7 pressure Ring, 71 threaded holes, 8 set screws, 9 cylindrical pins, 10 blind holes.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, the embodiments in the present application and the features in the embodiments may be arbitrarily combined with each other if there is no conflict.

As shown in FIGS. 1-3 , this embodiment provides a drift tube, including a drift tube body assembly and a drift tube end cover 4 , the drift tube body assembly includes a cylindrical drift tube body 3 , and the drift tube end cover 4 is fixed at one end of the drift tube body 3 . The shape and size of the drift tube end cap 4 are matched with the drift tube body 3 , the outer wall surface of one end of the drift tube body 3 is provided with external threads, and the inner wall surface of one end of the drift tube end cap 4 that matches the drift tube body 3 There are internal threads (as shown in Figures 6 and 7 ), which are fixedly connected through the cooperation of the external threads and the internal threads, so that the drift tube main body 3 and the drift tube end cover 4 are coaxial and tightly fitted.

In this embodiment, the drift tube end cap 4 and the drift tube main body 3 are connected by threads, which eliminates the electron beam welding fixing method between the drift tube main body 3 and the drift tube end cap 4 in the prior art, which simplifies the drift The processing procedure of the tube reduces the number of magnetic measurements and greatly reduces the processing difficulty of the drift tube. In addition, compared with the prior art, the thread connection processing process in this embodiment is simple and fast, and the deformation is small, which avoids the repairing process of welding deformation in the welding process, the defect of the welding seam area and the interference of the internal magnet to the welding process, and improves the performance of the welding process. The connection reliability and processing efficiency of the drift tube are improved, the processing cost is reduced, and the product yield is improved.

As shown in FIG. 3 , the main body 3 of the drift tube has a hollow cylindrical inner cavity, a water jacket 5 is fixed in the inner cavity (for example, fixed by electron beam welding), and a receiving cavity is formed in the water jacket 5 . There are permanent magnet quadrupole magnets 6 for focusing the particle beam passing through the drift tube. An annular water-cooling channel is formed between the inner wall of the drift tube main body 3 and the water jacket 5 for cooling the permanent magnet quadrupole magnet 6 in the accommodating cavity to ensure its working stability.

The main body 3 of the drift tube is also provided with a pressure ring 7. As shown in FIG. 3, the pressure ring 7 is fixed in the accommodating cavity. Through the pressure ring 7, the permanent magnet quadrupole magnet 6 (the outer casing of which is provided with a metal magnet skeleton) can be pressed tightly It is fixed on the cavity wall at the end of the accommodating cavity away from the end cap 4 of the drift tube, that is, the permanent magnet quadrupole magnet 6 is pressed against the end of the water jacket 5 away from the end cap 4 of the drift tube to ensure that the permanent magnet quadrupole magnet 6 is in There is no sliding in the direction of the central axis of the accommodating cavity. Compared with the existing drift tube in which the permanent magnet quadrupole magnet 6 is pressed and fixed on the end cover 4 of the drift tube by means of springs and pressing sheets, in this embodiment, a pressing ring 7 is installed in the accommodating cavity to make the pressing ring. 7. Lock the metal magnet skeleton and fix it directly in the accommodating cavity, thereby realizing the fixing of the permanent magnet quadrupole magnet on the drift tube main body 3, so that there is no direct connection between the pressure ring 7 and the drift tube end cover 4, avoiding drift After the tube end cover 4 is threadedly connected to the drift tube body 3, the thread of the drift tube end cover 4 is retracted due to the reaction force of the pressure magnet 6 acting on the drift tube end cover 4, which fully guarantees the drift tube body 3 and the drift tube body 3. The reliability of the screw connection between the pipe end caps 4.

As shown in Figures 8 and 9, the pressure ring 7 is annular, with an external thread on its outer wall, and an internal thread on the inner wall of the accommodating cavity. The permanent magnet quadrupole magnet 6 is pressed and fixed on the cavity wall at the end of the accommodating cavity away from the end cap 4 of the drift tube.

The pressure ring 7 is provided with a threaded hole 71, and the fastening screw 8 is directly pressed on the metal magnet skeleton after passing through the threaded hole 71, and the permanent magnet quadrupole magnet 6 is locked and fixed, thereby realizing the permanent magnet quadrupole magnet 6 and the drift tube. The main body is 3-phase fixed.

The pressure ring 7 is preferably made of a titanium alloy material, as long as it can meet the use requirements of non-magnetic, good mechanical properties, and high strength, and the specific material is not limited.

Specifically, when assembling, first put the permanent magnet quadrupole magnet 6 into the hollow accommodating cavity in the water jacket 5; The inner thread on the inner wall surface of the sleeve 5 is matched and fixed, and the permanent magnet quadrupole magnet 6 is pressed and fixed on the cavity wall of the end of the accommodating cavity away from the end cover 4 of the drift tube through the pressure ring 7; then, tighten the screw 8. Further lock and fix the metal magnet skeleton (ie, the permanent magnet quadrupole magnet 6 ) in the accommodating cavity of the water jacket 5 through the threaded hole 71 on the pressure ring 7 .

Optionally, the drift tube further includes a support rod 1, and the support rod 1 is in the form of a hollow cylindrical shape and is fixed to the drift tube main body 3 by electron beam welding. As shown in FIG. 4 and FIG. 5 , in this embodiment, a water separation column 2 is fixed on the drift tube main body 3 (for example, fixed by electron beam welding), and the support rod 1 is fixed on the upper end of the water separation column 2 by electron beam welding, thereby realizing It is fixed to the main body 3 of the drift tube. Specifically, firstly, the lower end of the water separation column 2 is fixed on the cylindrical outer wall surface of the drift tube main body 3 by electron beam welding, and then the lower end of the support rod 1 and the upper end of the water separation column 2 are connected by electron beam welding, that is, the support rod 1 is located at the upper end of the water separation column 2, so as to achieve the purpose of fixing the support rod 1 and the main body 3 of the drift tube.

After completing the fixed connection between the drift tube main body 3 and the support rod 1, use the support rod 1 as the benchmark to align, and repair the dimensions of the drift tube main body 3, the water separation column 2 and the support rod 1 to ensure that the support rod 1 is vertical. Straight arrangement, the drift tube main body 3 is arranged horizontally, and the central axis of the support rod 1 vertically intersects with the central axis of the drift tube main body 3 .

Next, the inner diameter of the water jacket 5 in the drift tube body 3 is adjusted based on the center axis of the drift tube body 3, so that the center axis of the accommodating cavity coincides with the center axis of the drift tube body 3, and the center of the support rod 1 is further adjusted. The axis perpendicularly intersects with the central axis of the accommodating cavity, so as to ensure that the intersection of the central axis of the support rod 1 and the central axis of the accommodating cavity falls within the required range of the geometric center coordinates of the drift tube main body 3 .

The existing drift tubes all need to be aligned with the connection body of the drift tube main body 3 equipped with the permanent magnet quadrupole magnet 6 and the drift tube end cover 4 as a benchmark to process the support rod 1. At this time, the alignment benchmark size is small, and the processing process is small. The middle tooling has high requirements and is difficult to process; the technical solution provided in this embodiment can weld and fix the support rod 1 before the permanent magnet quadrupole magnet 6 is assembled and the drift tube main body 3 is connected with the drift tube end cover 4, which not only avoids the need for magnets 6 Interference to the welding process, and can be aligned with the large support rod 1 entity to process and assemble the permanent magnet quadrupole magnet 6, the drift tube main body 3 and the drift tube end cover 4, so that the support rod, the permanent magnet quadrupole The machining accuracy and assembly accuracy of the magnet 6, the drift tube main body 3 and the drift tube end cover 4 are improved, and the machining and assembly process is simpler, which is beneficial to reduce the machining cost and improve the machining efficiency of the drift tube.

The present invention also provides a drift tube linear accelerator including the above-mentioned drift tube. By adopting the threaded connection between the drift tube main body 3 and the drift tube end cover 4, the assembly structure and processing sequence of the drift tube linear accelerator are improved, The mechanical structure of the drift tube linear accelerator using the permanent magnet quadrupole magnet 6 is simplified, the difficulty of processing and assembly is reduced, and various indexes of the drift tube linear accelerator are fully guaranteed.

The processing method of the drift tube provided by the present invention comprises the following steps:

Step 1: Preliminarily process the drift tube body 3 and the drift tube end cap 4, retain the machining allowance, and fix the drift tube body 3 with the water jacket 5 and the water separation column 2 to obtain the drift tube body assembly.

Specifically, first, the cylindrical shape and cylindrical inner cavity of the drift tube main body 3 and the drift tube end cap 4 are preliminarily processed, and the machining allowance is reserved, and a first port is opened at the end of the drift tube main body 3 away from the drift tube end cap 4 respectively. Hole 31, a second through hole 41 is formed on the end surface of the drift tube end cover 4; Specifically, when processing the drift tube end cap 4, in order to ensure the strength of the drift tube end cap 4, an inwardly protruding annular flange 42 is formed on the inner end face of the drift tube end cap 4 to avoid deformation during the processing. The wall thickness of the rest of the drift tube end cap 4 is reduced to reduce weight and material cost; then, internal threads are processed on the inner side wall of the drift tube end cap 4 .

Next, the water separation column 2 is preliminarily processed, and the installation groove of the water separation column 2 is processed on the cylindrical outer wall surface of the drift tube body 3 according to the outer diameter of the lower end of the water separation column 2; as shown in FIG. 3, according to the inner side of the drift tube body 3 The wall size and the outer diameter of the lower end of the water separation column 2, process the water jacket 5, and respectively process two groups of cylindrical pins on the water jacket 5 and the bottom end of the water separation column 2 for fixing the connection between the water separation column 2 and the water jacket 5. Then, fix the water jacket 5 on the inner side wall of the drift tube main body 3 by electron beam welding to form a receiving cavity; then, as shown in Figure 4 and Figure 5, pass the lower end of the water separation column 2 through the drift tube main body 3 The installation groove on the upper part extends downward to match with the water jacket 5, and the relative position between the lower end of the water separation column 2 and the water jacket 5 is pre-fixed by adding a cylindrical pin 9, and then the water separation column 2 is vertically welded and fixed on the main body of the drift tube. 3 on the installation groove to preliminarily complete the processing of the drift tube main assembly. The pre-positioning of the cylindrical pin 9 facilitates the electron beam welding and fixing of the water separation column 2 , improves the vertical welding accuracy of the water separation column 2 on the cylindrical outer side wall of the drift tube main body 3 , and thus ensures the fixing accuracy of the subsequent support rod 1 .

Step 2: further, preliminarily process the support rod, retain the machining allowance, and fix the support rod on the water separation column by electron beam welding.

Specifically, the shape and inner cavity of the support rod are preliminarily processed, the machining allowance is reserved, the support rod 1 is fixedly connected to the upper end of the water separation column 2 by electron beam welding, and the support rod 1 and the water separation column 2 are kept vertical. Thus, one end of the water separation column 2 is vertically fixed on the cylindrical outer side wall of the drift tube main body 3 , and the other end is vertically connected with the bottom end of the support rod 1 , so that the support rod 1 is vertically fixed on the drift tube main body 3 . Cylindrical outer wall.

Step 3: Further, repair the support rod 1, the water separation column 2, the drift tube main body 3 and the water jacket 5, so that the central axis of the support rod 1 and the central axis of the water separation column 2 are collinear, and the central axis of the support rod 1 and the drift The central axis of the tube main body 3 intersects vertically, the central axis of the accommodating cavity in the drift tube main body 3 is collinear with the central axis of the drift tube main body 3, and the central axis of the support rod 1 perpendicularly intersects with the central axis of the accommodating cavity.

Specifically, first, according to the welding deformation, the shape and inner diameter of the drift tube main body 3 and the water separation column 2 are modified so that the central axis of the support rod 1 and the central axis of the water separation column 2 are collinear; The drift tube main body 3 vertically intersects the central axis of the support rod 1 with the central axis of the drift tube main body 3 , that is, the central axis of the support rod 1 and the central axis of the water separation column 2 are perpendicularly intersected with the central axis of the drift tube main body 3 .

Then, the position of the drift tube main body 3 is fixed by a tool, that is, the central axis of the drift tube main body 3 is kept fixed, and the inner diameter of the water jacket 5 in the drift tube main body 3 is adjusted based on the central axis, so that the The central axis coincides with the central axis of the drift tube main body 3, so that the central axis of the support rod 1 and the central axis of the accommodating cavity are perpendicularly intersected, so as to ensure that the intersection of the central axis of the supporting rod 1 and the central axis of the accommodating cavity falls on the drift tube main body 3, and preliminarily meet the dimensions and tolerance requirements of the shape and inner diameter of the drift tube main body 3, the water separation column 2 and the support rod 1. The technical solution provided by this embodiment can weld and repair the support rod 1 before the permanent magnet quadrupole magnet 6 is assembled and the drift tube main body 3 is connected with the drift tube end cover 4 , which can not only prevent the internal magnet 6 from interfering with the welding process, but also , the cutting fluid can be used to cool the workpiece in time and remove chips during the processing, so as to better control the roughness of the workpiece, reduce welding deformation, and improve the machining accuracy of the drift tube.

Step 4: Further, in order to avoid the fact that the support rod 1 is finally connected in place in the prior art, the air tightness cannot be detected by vacuum in the early stage, and the final structure leaks. Vacuum detection is carried out on the connection structure of the supporting rod 1, the water separation column 2, the drift tube main body 3 and the water jacket 5 to ensure that the completed connection structure is complete and has good air tightness, which improves the overall yield of the processed parts and reduces the repair cost.

Step 5: Further, as shown in FIG. 3, the permanent magnet quadrupole magnet 6 (with a metal magnet skeleton on the outer jacket) is loaded into the hollow accommodating cavity in the main body 3 of the drift tube, and then the pressure ring 7 is loaded, but in the Before inserting the pressure ring 7, the inner thread is processed on the inner wall surface of the water jacket 5 (that is, the cavity wall of the accommodating cavity). The pressing ring 7 presses and fixes the permanent magnet quadrupole magnet 6 on the cavity wall at the end of the accommodating cavity away from the end cap 4 of the drift tube. Then, the tightening screw 8 is locked through the threaded hole 71 on the pressure ring 7 to lock the metal magnet skeleton set on the outer surface of the permanent magnet quadrupole magnet 6, thereby fixing the permanent magnet quadrupole magnet 6 in the accommodating cavity.

Since the central axis of the support rod 1 perpendicularly intersects with the central axis of the accommodating cavity in step 2, the central axis of the supporting rod 1 also intersects perpendicularly with the central axis of the permanent magnet quadrupole magnet 6 loaded into the accommodating cavity; The fixation not only makes the magnet 6 uniformly and stably fixed, but also ensures that there is no direct connection between the pressure ring 7 and the drift tube end cover 4, and avoids that after the drift tube end cover 4 and the drift tube main body 3 are threadedly connected, the permanent magnet The reaction force of the pole magnet 6 acts on the drift tube end cap 4, causing the thread of the drift tube end cap 4 to retreat, which fully ensures the reliability of the screw connection between the drift tube main body 3 and the drift tube end cap 4.

In addition, compared with the existing drift tube that first loads the permanent magnet quadrupole magnet 6 and then processes the support rod 1, the processing sequence in this embodiment is to install the permanent magnet quadrupole magnet 6 into the drift tube based on the support rod 1 The tube body 3 makes the assembly precision of the permanent magnet quadrupole magnet 6 higher.

Step 6: Further, an external thread is processed on the outer wall surface of the end of the drift tube main body 3 that is matched with the drift tube end cap 4, and a tool is used to make the external thread on the drift tube main body 3 and the drift tube end cap 4 with a constant torque. The inner thread of the drift tube is matched to realize the threaded connection of the drift tube main body 3 and the drift tube end cover 4, and ensure that the center axis of the first through hole 31 and the center axis of the second through hole 41 are collinear as much as possible.

Step 7: Further, perform magnetism measurement on the above-mentioned assembled whole, that is, use a vibration wire magnetic center measuring device and method of a fixed magnet (for details, please refer to the description part of the patent application number CN201710354648.2) to measure the permanent magnet The magnetic center coordinates of the quadrupole magnet 6 ensure that the measured magnetic center coordinates of the permanent magnet quadrupole magnet 6 fall within the required range of the geometric center coordinates of the drift tube main body 3 and meet the accuracy requirements of the magnetic center data.

According to the magnetic measurement results, if there is a magnetic center offset, the shape and inner diameter of the drift tube main body 3, the water separation column 2 and the support rod 1 can be slightly modified according to the offset to meet the data accuracy requirements of the magnetic center.

Step 8: Further, take the main body 3 of the drift tube and the support rod 1 as the benchmark for comprehensive alignment, refer to the magnetic center data, and modify the shapes of the support rod 1, the water separation column 2, the main body 3 of the drift tube, and the end cap 4 of the drift tube. , and finish the support rod 1 and the water separation column 2 in place to ensure that the central axis of the support rod 1 and the water separation column 2 passes through the magnetic center of the magnet 6, and meets the size requirements of the support rod 1 and the water separation column 2.

After reaching the standard, the keyway and target ball hole on the support rod 1 are processed to complete the processing of all the structures of the support rod 1.

Step 9: Further, aligning the support rod 1 as a reference, and perform final finishing on the drift tube end cap 4 and the drift tube body 3 . Specifically, first, the four blind holes 10 on the cylindrical outer side wall surface of the drift tube main body 3 are processed, as shown in FIG. When machining the tapered surface, the tool squeezes the drift tube body 3 and the drift tube end cover 4 to further tighten the threaded connection between the drift tube body 3 and the drift tube end cover 4; The shape and structure of the tube end cover 4 are finished (for example, the outer side wall surface, the inclined surface, the fillet, the first through hole 31 and the second through hole 41 of the drift tube main body 3 and the drift tube end cover 4 are finished) to ensure Surface finish, improve the machining accuracy of drift tube.

To sum up, the drift tube provided by the above embodiments of the present invention adopts the screw connection between the drift tube main body and the drift tube end cover, and adds a pressure ring to press and fix the permanent magnet four-stage magnet in the drift tube main body. In the cavity, when processing the drift tube, the support rod can be welded first and then the permanent magnet quadrupole magnet can be installed. Based on the support rod, the overall dimensions of the drift tube body can be modified and the permanent magnet quadrupole magnet can be assembled, so that the drift tube body can be machined. The difficulty is reduced, the assembly precision of the permanent magnet quadrupole magnet is higher, and the number of magnetic measurements is effectively reduced, thereby making the processing of the drift tube simpler, lower in cost, and higher in precision, improving the reliability of the drift tube and the overall yield of the processed parts.

Although the embodiments disclosed in the present invention are as above, the described contents are only the embodiments adopted to facilitate the understanding of the present invention, and are not intended to limit the present invention. Any person skilled in the art to which the present invention belongs, without departing from the spirit and scope disclosed by the present invention, can make any modifications and changes in the form and details of the implementation, but the scope of the patent protection of the present invention still needs to be as defined by the appended claims.

Claims (8)

1. A drift tube, comprising: drift tube body subassembly and drift tube end cover, drift tube body subassembly includes the drift tube main part, the drift tube end cover is fixed in one end of drift tube main part, its characterized in that: one end of the drift tube main body is in threaded connection with the drift tube end cover, an external thread is arranged on the outer wall surface of one end of the drift tube main body, and an internal thread matched with the external thread is arranged on the inner wall surface of one end, matched with the drift tube main body, of the drift tube end cover.

2. The drift tube of claim 1, wherein: still include permanent magnetism quadrupole magnet, have in the drift tube main part and hold the chamber, permanent magnetism quadrupole magnet locates hold the intracavity, it has the clamping ring to hold the intracavity, the clamping ring will permanent magnetism quadrupole magnet compresses tightly to be fixed hold keeping away from of chamber on the chamber wall of the one end of drift tube end cover.

3. The drift tube of claim 2, wherein: the pressing ring is in threaded connection with the cavity wall of the accommodating cavity.

4. The drift tube of claim 2, wherein: and the pressing ring is provided with a threaded hole, and a fastening screw passes through the threaded hole and tightly presses the permanent magnet quadrupole magnet.

5. The drift tube of any of claims 1 to 4, wherein: the drift tube comprises a drift tube body assembly and is characterized by further comprising a supporting rod, wherein the supporting rod and the drift tube body assembly are fixed through electron beam welding.

6. A drift tube linear accelerator, characterized by: comprising a drift tube according to any of claims 1 to 5.

7. A method for processing a drift tube is characterized by comprising the following steps:

preliminarily processing a drift tube main body and a drift tube end cover, reserving processing allowance, and fixing the drift tube main body with a water jacket and a water dividing column to obtain a drift tube main body assembly;

preliminarily processing the support rod, reserving processing allowance, and fixing the support rod on the water diversion column through electron beam welding;

the support rod, the water dividing column, the drift tube main body and the water jacket are repaired, so that the central axis of the support rod is collinear with the central axis of the water dividing column, the central axis of the support rod is vertically intersected with the central axis of the drift tube main body, and the central axis of an accommodating cavity in the drift tube main body is collinear with the central axis of the drift tube main body;

detecting the air tightness of a connecting structure of the support rod, the water dividing column, the drift tube main body and the water jacket so as to ensure that no leakage exists in the connecting structure and a welding connecting area;

assembling a permanent magnetic quadrupole magnet in an accommodating cavity in the drift tube main body;

processing external threads on the drift tube main body, and connecting the drift tube main body and the drift tube end cover in a threaded manner;

measuring the magnetic center coordinate of the permanent magnet quadrupole magnet by using a vibrating wire magnetic center measuring device and a vibrating wire magnetic center measuring method for fixing the magnet so as to ensure that the magnetic center coordinate of the permanent magnet quadrupole magnet falls within the required range of the geometric center coordinate of the drift tube main body;

comprehensively aligning by taking the drift tube main body and the support rod as a reference, and finely machining the support rod and the water diversion column in place by referring to magnetic center data to ensure that the central axes of the support rod and the water diversion column cross the magnetic center, and the sizes of the support rod and the water diversion column meet the requirements;

and aligning by taking the support rod as a reference, and finely machining the drift tube main body and the drift tube end cover to ensure that the drift tube main body and the drift tube end cover meet the requirements of size and finish degree.

8. The method of claim 7 wherein a cutting fluid is used during the steps of assembling said drift tube body, said support rods, said water jacket and said water dividing column before installing said permanent magnet quadrupole magnet.

Images