Collimation structure and collimation method of superconducting acceleration unit

Abstract

This invention relates to the field of low-temperature superconductivity and particle accelerator technology, and particularly to a collimation structure and collimation method for a superconducting accelerator unit. The collimation structure includes: a vacuum chamber with a cavity for providing an adiabatic vacuum environment; a cold mass string disposed within the cavity of the vacuum chamber; a cold support frame for supporting the cold mass string; and a support member disposed between the vacuum chamber and the cold support frame to reduce heat transfer. The vacuum chamber includes a base plate, and the support member engages with the base plate and the cold support frame in three dimensions according to a Cartesian coordinate system to decouple the positioning of the cold mass string within the vacuum chamber. In this invention, by decoupling the positioning of the cold mass string, it is unnecessary to perform collimation measurements and adjustments on each cold mass element, thus reducing on-site integration workload and improving the acceleration and focusing efficiency of the accelerator beam, thereby enhancing beam quality.

Description

Technical Field

[0001] This invention relates to the field of low-temperature superconductivity and particle accelerator technology, and in particular to a collimation structure and collimation method for a superconducting accelerator unit. Background Technology

[0002] As the most important component of a superconducting linear accelerator, the superconducting acceleration unit provides the 2K / 4K cryogenic environment and adiabatic vacuum environment required for the operation of cold mass components, including superconducting cavities and superconducting solenoids, and ensures that they meet certain beam collimation characteristics.

[0003] The cold mass string, consisting of multiple superconducting cavities and superconducting solenoids, is located above the bottom plate of the vacuum chamber and is supported and connected by thermal insulation components. The positional accuracy of the cold mass element is affected by two factors: the deformation of the bottom plate and the shrinkage deformation of the material at low temperature. The positional accuracy of the superconducting cavity in the cold mass element will affect the particle acceleration efficiency in the beam channel, and the positional accuracy of the superconducting solenoid will affect the particle focusing efficiency in the beam channel.

[0004] Currently, superconducting linear accelerator units mainly rely on collimation measurement and three-dimensional adjustment of cold mass elements at room temperature to improve the positional accuracy of the elements. In the field integration operation, it is necessary to collimate each cold mass in each superconducting accelerator unit and adjust it in three dimensions, which consumes a lot of time and resources. Moreover, the three-dimensional adjustment mechanism has poor stability and limited adjustment accuracy, which is not conducive to the mass production and industrial application of superconducting accelerator units.

[0005] To address this, a collimation structure and collimation method for a superconducting accelerator unit are proposed. By designing the process flow, the positional accuracy of the cold mass element is ensured, thus eliminating the need for collimation measurement and adjustment of each cold mass element. This reduces the workload of on-site integration while improving the acceleration and focusing efficiency of the accelerator beam and enhancing beam quality. Summary of the Invention

[0006] This invention aims to solve the technical problems existing in related technologies. To this end, this invention proposes a collimation structure and collimation method for a superconducting accelerator unit, so as to decouple the positioning of the cold mass element in the superconducting accelerator unit, thereby ensuring the positioning accuracy of the cold mass element and improving the acceleration efficiency and focusing efficiency of the accelerator beam.

[0007] In a first aspect, the present invention provides a collimation structure for a superconducting acceleration unit, comprising:

[0008] A vacuum chamber is provided with a containment cavity for providing an adiabatic vacuum environment;

[0009] A cold mass string is disposed within the containment cavity of the vacuum chamber;

[0010] A cold support, configured as a frame structure to support the cold mass string;

[0011] A support member is disposed between the vacuum chamber and the cooling support to reduce heat transfer;

[0012] The vacuum chamber includes a base plate, and the support member cooperates with the base plate and the cold support in three dimensions according to the Cartesian coordinate system, so as to decouple the cold mass string from the positioning within the vacuum chamber.

[0013] According to the present invention, a collimation structure for a superconducting acceleration unit is provided, wherein a finely machined small plane is provided on the upper surface of the base plate, the support member is connected to the finely machined small plane, and the XZ plane of the Cartesian coordinate system coincides with the finely machined small plane, so as to enable the cold mass string to be accurately positioned in the XZ plane.

[0014] According to the present invention, a collimation structure for a superconducting acceleration unit is provided, wherein the cold support includes a top surface and a bottom surface of the support that are parallel to each other, and the support member includes an upper support end surface and a lower support end surface that are parallel to each other.

[0015] The height between the top surface and the bottom surface of the bracket, and the height between the upper support end face and the lower support end face, are all subject to negative tolerances. This is to ensure that the cumulative height of the cold bracket and the support member in the Y-axis direction perpendicular to the XZ plane is less than the theoretical value.

[0016] The collimation structure of a superconducting acceleration unit provided by the present invention further includes a compensation shim disposed between the cold support and the support member, for increasing the actual height of the cold mass relative to the finished small plane in the Y-axis direction of the Cartesian coordinate system to the theoretical height.

[0017] According to the collimation structure of a superconducting acceleration unit provided by the present invention, the base plate is provided with an assembly hole in the area of ​​the precision-machined small plane, and the lower support end face of the support member is in contact with the precision-machined small plane and is precisely positioned through the assembly hole.

[0018] According to the present invention, a collimation structure for a superconducting acceleration unit is provided, wherein the cold mass string includes a superconducting cavity and a superconducting solenoid, the superconducting cavity is provided with four supporting lugs, the superconducting solenoid is provided with two supporting lugs, and the lower surface of the supporting lugs is parallel to the centerline of the beam channel of the cold mass string.

[0019] Secondly, the present invention provides a collimation method for a superconducting acceleration unit, applicable to the collimation structure of any of the superconducting acceleration units described above.

[0020] According to the collimation method of a superconducting acceleration unit provided by the present invention, S1, a finely machined small plane is set on the bottom plate of the vacuum chamber, and the finely machined small plane is used as the XZ plane of the Cartesian coordinate system, with the direction perpendicular to the XZ plane upward as the positive direction of the Y axis, and the direction of the beam forward in the cold mass train as the positive direction of the Z axis.

[0021] S2. According to the machining requirements of negative tolerance dimensions for height, the upper and lower support end faces of the support component, as well as the top and bottom surfaces of the cold bracket, are precision machined.

[0022] S3. Pre-assemble at room temperature, install the support, cold bracket and cold mass string into the vacuum chamber in sequence, install compensation shims between the support and the cold bracket, and adjust the actual height of the beam channel in the cold mass string in the Y-axis direction to the theoretical height.

[0023] According to the collimation method of a superconducting acceleration unit provided by the present invention, the height dimension of the compensation shim is equal to the vector sum of the first parameter, the second parameter and the third parameter;

[0024] The first parameter is the difference between the theoretical height of the beam channel and the actual assembly dimensions of the support and cold support. The second parameter is the deformation of the vacuum chamber floor plate under adiabatic conditions. The third parameter is the amount of shrinkage deformation of each component in the support and cold mass string in the Y-axis direction.

[0025] According to the collimation method of a superconducting acceleration unit provided by the present invention, four pin holes are provided on the bottom plate of the vacuum chamber, the geometric center of the bottom plate is determined by the four pin holes, and the origin of the Cartesian coordinate system is set to coincide with the geometric center of the bottom plate.

[0026] The above-described one or more technical solutions of this invention have at least one of the following technical effects:

[0027] The collimation structure decomposes the mounting reference of the cold mass element in the superconducting accelerator unit in three dimensions of the Cartesian coordinate system, decoupling the positioning reference in the Y direction from the positioning reference in the X and Z directions. This reduces the workload of on-site assembly and ensures the positioning accuracy of the cold mass element in the superconducting accelerator unit, thereby improving the acceleration efficiency and focusing efficiency of the accelerator particle beam.

[0028] In the collimation structure, the height parameters of the support and cold bracket are designed with negative tolerance dimensions. The total height after assembly with the vacuum chamber floor is lower than the theoretical dimension. This height difference is compensated and adjusted during pre-assembly by setting compensation shims.

[0029] In addition to the technical problems solved by the present invention, the technical features of the technical solutions constituted by the present invention, and the advantages brought about by the technical features of these technical solutions as described above, other technical features of the present invention and the advantages brought about by these technical features will be further explained in conjunction with the accompanying drawings, or will be learned through the practice of the present invention. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the collimation structure of the superconducting acceleration unit provided in an embodiment of the present invention.

[0032] Figure 2 A flowchart of the collimation method for a superconducting acceleration unit provided in an embodiment of the present invention.

[0033] Figure label:

[0034] 1. Vacuum chamber; 11. Base plate; 2. Support component; 3. Cold support; 4. Cold mass string; 41. Superconducting cavity; 42. Superconducting solenoid. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0036] In an embodiment of the present invention, a collimation structure for a superconducting acceleration unit is described.

[0037] like Figure 1 As shown, the collimation structure mainly includes a vacuum chamber 1, a cold mass string 4, a cold support 3, and a support component 2.

[0038] Vacuum chamber 1 is provided with a receiving cavity for providing an adiabatic vacuum environment. The cold mass string 4 is disposed within the receiving cavity of vacuum chamber 1. The cold support 3 is configured as a frame structure for supporting the cold mass string 4.

[0039] The support 2 is positioned between the vacuum chamber 1 and the cold support 3 to reduce heat transfer.

[0040] Vacuum chamber 1 includes a base plate 11. Support member 2 engages with base plate 11 and cold support 3 in three dimensions according to the Cartesian coordinate system, and is used to decouple the positioning of cold mass string 4 within vacuum chamber 1.

[0041] The cold mass string 4 includes a superconducting solenoid 42 that functions as a focusing element and a superconducting cavity 41 that functions as an acceleration element. Specifically, the cold mass string 4 is composed of several superconducting solenoids 42 and several superconducting cavities 41 connected in series. Furthermore, different arrangements and combinations are used according to different acceleration requirements to obtain accelerated particle beams with different energies.

[0042] The upper surface of the bottom plate 11 of vacuum chamber 1 serves as the XZ plane of the Cartesian coordinate system. The positive Z-axis is the direction of beam propagation in the cold mass string 4, the positive Y-axis is perpendicular to the XZ plane and upward, and the positive X-axis can be determined by the right-hand rule.

[0043] Furthermore, the upper surface of the base plate 11 is provided with a finely machined small flat surface.

[0044] Support 2 is connected to the precision-machined small plane, and the XZ plane of the Cartesian coordinate system coincides with the precision-machined small plane, which is used to accurately position the cold mass string 4 in the XZ plane.

[0045] Meanwhile, areas outside the precision-machined small plane are not precision-machined, which shortens the processing cycle of the base plate 11 on the one hand, and reduces the stress and strain of the base plate 11 during the processing on the other hand, thereby improving the flatness of the precision-machined small plane.

[0046] The base plate 11 has assembly holes in the area of ​​the precision-machined small plane. The lower support end face of the support member 2 fits into the precision-machined small plane. Furthermore, the support member 2 is precisely positioned on the base plate 11 of the vacuum chamber 1 through the assembly holes, so that the cold mass string 4 can be adjusted on the XZ plane during the pre-assembly stage. In the on-site integration and assembly operation, there is no need to perform collimation measurement, which optimizes the integration and assembly process of the superconducting accelerator unit, reduces the cost of mass production of the superconducting accelerator unit, and improves the efficiency of the integration and assembly operation.

[0047] Furthermore, the cold mass string 4 includes a superconducting cavity 41 and a superconducting solenoid 42. The superconducting cavity 41 is provided with four supporting lugs, and the superconducting solenoid 42 is provided with two supporting lugs. The lower surface of the supporting lugs is parallel to the center line of the beam channel of the cold mass string 4.

[0048] In this embodiment, the mounting reference of the cold mass element in the superconducting acceleration unit is decomposed in three dimensions of the Cartesian coordinate system, and the positioning reference in the Y direction is decoupled from the positioning reference in the X and Z directions. This reduces the workload of on-site assembly and ensures the positioning accuracy of the cold mass element in the superconducting acceleration unit, thereby improving the acceleration efficiency and focusing efficiency of the accelerator particle beam.

[0049] Based on the above embodiments, another embodiment of the present invention introduces a collimation structure for a superconducting acceleration unit.

[0050] The cold support bracket 3 includes a top surface and a bottom surface that are parallel to each other. The support member 2 includes an upper support end surface and a lower support end surface that are parallel to each other. The top surface, bottom surface, upper support end surface, and lower support end surface of the bracket are all parallel to the precision-machined small plane and are used to adjust the height of the cold mass string 4 in the Y-axis direction perpendicular to the XZ plane.

[0051] Specifically, the height between the top and bottom surfaces of the support bracket adopts a negative tolerance dimension. The height between the upper and lower support end faces also adopts a negative tolerance dimension.

[0052] Several finely machined small planes coinciding with the XZ plane are provided on the base plate 11 of the vacuum chamber 1. When the cold support 3 and the support member 2 are assembled into the vacuum chamber 1, the upper support end face is in close contact with the bottom surface of the support, and the lower support end face is in close contact with the finely machined small planes. The cumulative height of the cold support 3 and the support member 2 in the Y-axis direction perpendicular to the XZ plane is less than the theoretical value, so that the actual height of the beam channel of the cold mass string 4 is less than the theoretical size.

[0053] In addition, the collimation structure also includes compensation shims. The compensation shims are disposed between the cold support 3 and the support 2, and are used to increase the actual height of the cold mass string 4 relative to the machined small plane in the Y-axis direction of the Cartesian coordinate system to the theoretical height.

[0054] In this embodiment, the height parameters of the support member 2 and the cold bracket 3 are designed to have negative tolerance dimensions. The total height after assembly with the vacuum chamber 1 base plate 11 is lower than the theoretical dimension. This height difference is compensated and adjusted during pre-assembly by setting compensation shims.

[0055] Furthermore, in another embodiment of the present invention, a collimation method for a superconducting accelerator unit is described. This collimation method is applied to the collimation structure of the superconducting accelerator unit in any of the above embodiments.

[0056] like Figure 2 As shown, the collimation method includes the following steps:

[0057] S1. A finely machined small plane is set on the bottom plate 11 of the vacuum chamber 1. The finely machined small plane is used as the XZ plane of the Cartesian coordinate system. The direction perpendicular to the XZ plane and upward is the positive direction of the Y axis, and the direction of the beam in the cold mass string 4 is the positive direction of the Z axis.

[0058] Preferably, mounting holes are provided within the area of ​​the precision-machined small facet. Then, the support member 2 is positioned on the XZ plane through the mounting holes.

[0059] S2. According to the machining requirements of negative tolerance for height, the upper and lower support end faces of support member 2, as well as the top and bottom surfaces of cold bracket 3, are precision machined.

[0060] S3. Pre-assemble at room temperature, install the support 2, cold bracket 3 and cold mass string 4 into the vacuum chamber 1 in sequence, install compensation shims between the support 2 and the cold bracket 3, and adjust the actual height of the beam channel in the cold mass string 4 in the Y-axis direction to the theoretical height.

[0061] In this method, by precision machining the support 2 and the key dimensions of the cold-formed components, the height difference requirement of the beam center of each component in the cold mass string 4 in the Y direction is ensured, and the beam channel of the cold mass string 4 is parallel to the XZ plane. Then, assembly holes are set in the precision-machined small plane to accurately position the cold mass string 4 in the XZ plane. In terms of process, the positioning accuracy of the cold mass string 4 in the superconducting acceleration unit is guaranteed, thereby improving the acceleration efficiency of the accelerator particle beam.

[0062] Furthermore, the height dimension of the compensation shim is equal to the vector sum of the first parameter, the second parameter, and the third parameter.

[0063] The first parameter is the difference between the theoretical height of the beam channel and the actual assembly dimensions of the support component 2 and the cold support 3. The second parameter is the deformation of the base plate 11 of the vacuum chamber 1 under adiabatic conditions. The third parameter is the amount of shrinkage deformation of each component in the support component 2 and the cold mass string 4 in the Y-axis direction.

[0064] Furthermore, four pin holes are provided on the base plate 11 of the vacuum chamber 1 to determine the geometric center of the base plate 11, and the origin of the Cartesian coordinate system is set to coincide with the geometric center of the base plate 11.

[0065] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0066] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0067] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0068] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms are not limited to the same embodiments or examples. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A collimation structure of a superconducting acceleration unit, characterized in that, include: The vacuum chamber (1) is provided with a containment cavity for providing an adiabatic vacuum environment; A cold mass string (4) is disposed within the containment cavity of the vacuum chamber (1); The cold support (3) is configured as a frame structure to support the cold mass string (4); A support member (2) is disposed between the vacuum chamber (1) and the cold support (3) to reduce heat transfer; The vacuum chamber (1) includes a base plate (11), and the support member (2) cooperates with the base plate (11) and the cold support (3) in three dimensions according to the Cartesian coordinate system, respectively, to decouple the positioning of the cold mass string (4) in the vacuum chamber (1); The upper surface of the base plate (11) is provided with a finely machined small plane. The support member (2) is connected to the finely machined small plane. The XZ plane of the Cartesian coordinate system coincides with the finely machined small plane, which is used to make the cold mass string (4) accurately positioned in the XZ plane.

2. The collimation structure of a superconducting acceleration unit according to claim 1, characterized in that The cold support (3) includes a support top surface and a support bottom surface that are parallel to each other, and the support member (2) includes an upper support end surface and a lower support end surface that are parallel to each other. The height between the top surface of the bracket and the bottom surface of the bracket, and the height between the upper support end face and the lower support end face, are all negative tolerance dimensions, which are used to ensure that the cumulative height of the cold bracket (3) and the support member (2) in the Y-axis direction perpendicular to the XZ plane is less than the theoretical value.

3. The collimation structure of a superconducting acceleration unit according to claim 2, characterized in that It also includes a compensation shim disposed between the cold support (3) and the support member (2) for increasing the actual height of the cold mass string (4) relative to the finishing plane in the Y-axis direction of the Cartesian coordinate system to the theoretical height.

4. The collimation structure of a superconducting acceleration unit according to claim 3, characterized in that The base plate (11) has an assembly hole in the area of ​​the precision-machined small plane, and the lower support end face of the support member (2) is attached to the precision-machined small plane and is precisely positioned through the assembly hole.

5. The collimation structure of a superconducting acceleration unit according to claim 4, characterized in that The cold mass string (4) includes a superconducting cavity (41) and a superconducting solenoid (42). The superconducting cavity (41) is provided with four supporting lugs, and the superconducting solenoid (42) is provided with two supporting lugs. The lower surface of the supporting lugs is parallel to the center line of the beam channel of the cold mass string (4).

6. A collimation method of a superconducting accelerating unit, characterized by, Collimation structure applied to the superconducting acceleration unit as described in any one of claims 1 to 5; Collimation methods include: S1. Set a fine-machining small plane on the bottom plate (11) of the vacuum chamber (1), and take the fine-machining small plane as the XZ plane of the Cartesian coordinate system, take the direction perpendicular to the XZ plane upward as the positive direction of the Y axis, and take the direction of the beam in the cold mass string (4) as the positive direction of the Z axis. S2. According to the machining requirements of the height value being a negative tolerance dimension, the upper support end face and lower support end face of the support member (2), as well as the top surface and bottom surface of the cold bracket (3) are precision machined. S3. Pre-assemble at room temperature, install the support (2), cold bracket (3) and cold mass string (4) into the vacuum chamber (1) in sequence, install compensation shims between the support (2) and the cold bracket (3), and adjust the actual height of the beam channel in the cold mass string (4) in the Y-axis direction to the theoretical height.

7. The method of collimation of a superconducting acceleration unit according to claim 6, characterized in that, The height dimension of the compensation gasket is equal to the vector sum of the first parameter, the second parameter and the third parameter; The first parameter is the difference between the theoretical height value of the beam channel and the actual assembly size of the support (2) and the cold support (3), the second parameter is the deformation amount of the bottom plate (11) of the vacuum chamber (1) in the adiabatic environment, and the third parameter is the cold shrinkage deformation amount of each element in the Y-axis direction in the support (2) and the cold mass string (4).

8. The collimation method of a superconducting acceleration unit according to claim 7, characterized in that, Four pin holes are arranged on the bottom plate (11) of the vacuum chamber (1), the geometric center of the bottom plate (11) is determined through the four pin holes, and the origin of the Cartesian coordinate system is arranged to coincide with the geometric center of the bottom plate (11).

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