Method for adjusting deviation of magnetic center of arc-shaped superconducting coil

Abstract

The invention provides an arc-shaped superconducting coil magnetic center offset adjusting method comprising the following steps: obtaining a to-be-processed arc-shaped superconducting coil model, the arc-shaped superconducting coil comprising a plurality of parameters; respectively determining a first parameter target value, a second parameter target value, a third parameter target value and a fourth parameter target value in the plurality of parameters based on a preset swarm intelligence algorithm; according to the first parameter target value, the second parameter target value, the third parameter target value and the fourth parameter target value, the magnetic center of the arc-shaped superconducting coil is adjusted to the initial target position; after the magnetic center of the arc-shaped superconducting coil is adjusted to the initial target position, the magnetic center is moved to the geometric center of the framework by adjusting the depth of the framework wire slot of the arc-shaped superconducting coil; wherein the arc-shaped superconducting coil framework is used for supporting the arc-shaped superconducting coil.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting magnets for medical ion therapy accelerators, and particularly to a method for adjusting the magnetic center offset of an arc-shaped superconducting coil. Background Art

[0002] In the current field of coil-dominated superconducting magnets for medical ion therapy accelerators, coil-dominated superconducting magnets are often used in medical ion accelerators due to their small volume, light weight, and ability to achieve multi-pole compounding. However, the arc-shaped structure often causes the magnetic center of the superconducting coil to shift, that is, the magnetic center of the arc-shaped superconducting coil is often not at the geometric center of the coil cross-section. This situation will seriously affect the beam operation. Therefore, it is urgent to correct the magnetic center of the superconducting coil through relevant methods. Summary of the Invention

[0003] (I) Technical Problems to be Solved

[0004] In view of the above deficiencies, the main object of the present invention is to provide a method for adjusting the magnetic center offset of an arc-shaped superconducting coil, which solves the problem of the magnetic center offset of the superconducting coil caused by the arc-shaped structure and eliminates the serious interference to the beam operation in the multi-pole compound magnetic field.

[0005] (II) Technical Solutions

[0006] To achieve the above object, the present invention provides a method for adjusting the magnetic center offset of an arc-shaped superconducting coil, including: obtaining an arc-shaped superconducting coil model to be processed, where the arc-shaped superconducting coil includes multiple parameters; based on a preset swarm intelligence algorithm, respectively determining the target values of the first parameter, the second parameter, the third parameter, and the fourth parameter among the multiple parameters; according to the target values of the first parameter, the second parameter, the third parameter, and the fourth parameter, adjusting the magnetic center of the arc-shaped superconducting coil to the initial target position; after adjusting the magnetic center of the arc-shaped superconducting coil to the initial target position, moving the magnetic center to the geometric center of the skeleton by adjusting the depth of the skeleton wire groove of the arc-shaped superconducting coil; wherein, the arc-shaped superconducting coil skeleton is used to support the arc-shaped superconducting coil.

[0007] In the above solution, according to the target values of the first parameter, the second parameter, the third parameter, and the fourth parameter, adjusting the magnetic center of the arc-shaped superconducting coil to the initial target position includes: based on the target values of the first parameter, the second parameter, the third parameter, and the fourth parameter, adjusting the magnetic center of the arc-shaped superconducting coil to the initial target position by adjusting the current distribution of the arc-shaped superconducting coil cross-section.

[0008] In the above solution, the initial target position is within 0.3 mm from the geometric center of the arc-shaped superconducting coil.

[0009] In the above solution, by adjusting the depth of the groove of the arc-shaped superconducting coil skeleton, the magnetic center is moved to the geometric center of the skeleton, including: by adjusting the depth of the groove of the arc-shaped superconducting coil skeleton, the magnetic center of the arc-shaped superconducting coil is moved to the geometric center of the skeleton in the form of overall translation.

[0010] In the above solution, the setting ranges of the first parameter target value, the second parameter target value, the third parameter target value, and the fourth parameter target value are all -0.1 V / m to 0.1 V / m.

[0011] In the above solution, the first parameter, the second parameter, the third parameter, and the fourth parameter are the dipole field component, the quadrupole field component, the hexapole field component, and the octupole field component respectively.

[0012] In the above solution, obtaining the arc-shaped superconducting coil model to be processed includes: based on a preset shape function, determining the arc-shaped superconducting coil model by adjusting multiple parameters of the arc-shaped superconducting coil.

[0013] In the above solution, the fifth parameter, the sixth parameter, the seventh parameter, and the eighth parameter among the multiple parameters are all determined according to the design requirements of the superconducting magnet.

[0014] (III) Beneficial Effects

[0015] The technical solution of the embodiment of the present invention has at least the following beneficial effects:

[0016] (1) This method realizes the adjustment of the magnetic center of the arc-shaped superconducting coil to the geometric center of the magnet cross-section by combining coil adjustment and mechanical adjustment, solves the problem of the magnetic center offset of the superconducting coil caused by the arc-shaped structure, and eliminates the serious interference to the beam operation in the multipole composite magnetic field.

[0017] (2) This method is simple and efficient, and is applicable to various coil-dominated superconducting magnets at the same time, with strong versatility and good practicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematically shows a flowchart of a method for adjusting the magnetic center offset of an arc-shaped superconducting coil according to an embodiment of the present invention;

[0019] Figure 2 Schematically shows an overall view of an arc-shaped superconducting coil model according to an embodiment of the present invention;

[0020] Figure 3 Schematically shows a partial cross-sectional view of an arc-shaped superconducting coil model according to an embodiment of the present invention;

[0021] Figure 4 Schematically shows a cross-sectional current distribution diagram of an arc-shaped superconducting coil according to an embodiment of the present invention;

[0022] Figure 5 Schematic diagram showing an arc-shaped superconducting coil placed in a skeleton wire groove according to an embodiment of the present invention. Detailed implementation manners

[0023] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to specific embodiments and the accompanying drawings.

[0024] Figure 1 Schematic flowchart showing a method for adjusting the magnetic center offset of an arc-shaped superconducting coil according to an embodiment of the present invention. Figure 2 Schematic global view of an arc-shaped superconducting coil model according to an embodiment of the present invention. Figure 3 Schematic partial cross-sectional view of an arc-shaped superconducting coil model according to an embodiment of the present invention.

[0025] As Figure 1 shown, the method for adjusting the magnetic center offset of an arc-shaped superconducting coil specifically includes operations S1 to S4.

[0026] In operation S1, an arc-shaped superconducting coil model to be processed is obtained, and the arc-shaped superconducting coil includes multiple parameters.

[0027] According to an embodiment of the present invention, in order to perform the offset adjustment of the magnetic center in the first stage of the arc-shaped superconducting coil, it is first necessary to determine the structure and coil distribution of the main body model of the arc-shaped superconducting coil, and then adjust the offset of the magnetic center of the superconducting coil by adjusting the coil parameters of the arc-shaped superconducting coil.

[0028] In an embodiment of the present invention, based on a preset shape function, by adjusting multiple parameters of the arc-shaped superconducting coil, an arc-shaped superconducting coil model is determined.

[0029] It can be understood that the arc-shaped superconducting coil model is determined by multiple parameters. For example, it can be determined by 8 parameters. Among them, the fifth parameter, the sixth parameter, the seventh parameter, and the eighth parameter can be the number of coil layers, the number of coil turns, the length of the coil end, and the length of the straight section of the coil respectively. These four parameters are all parameters determined according to the design requirements of the superconducting magnet before establishing the model, so that the main structure size of the arc-shaped superconducting coil can be determined.

[0030] Furthermore, the first parameter, the second parameter, the third parameter, and the fourth parameter are all coil parameters, and can be the dipole field component, the quadrupole field component, the hexapole field component, and the octupole field component respectively.

[0031] As Figure 2 and Figure 3 shown, based on a preset shape function, according to the above 8 parameters, the establishment of the arc-shaped superconducting coil model to be processed can be completed based on 3D modeling software, and the coil model is composed of multiple coils 5.

[0032] Exemplarily, taking a DCT type superconducting coil as an example, its coil distribution can be expressed by a set of shape functions:

[0033]

[0034]

[0035] Among them, the coil distribution is determined by a total of 8 parameters including m1~m4, nn, N, L e , L st A total of 8 parameters determine the coil distribution, among which nn, N, L e , L st The four parameters of the number of coil layers, the number of coil turns, the length of the coil end, and the length of the straight section of the coil need to be determined in advance according to the design requirements of the superconducting magnet (such as magnetic field value, effective length, deflection angle) before establishing the model to determine the main structure size of the DCT superconducting coil. Among them, m1~m4 are the dipole field component, quadrupole field component, hexapole field component, and octupole field component respectively.

[0036] It should be noted that in the embodiments of the present invention, it is not only applicable to DCT (discrete-cosine-theta) type superconducting coils, but also applicable to arc-shaped CCT (canted-cosine-theata), arc-shaped serpentine coils, and arc-shaped costine-theta coils.

[0037] In operation S2, based on a preset swarm intelligence algorithm, the target values of the first parameter, the second parameter, the third parameter, and the fourth parameter among multiple parameters are determined respectively.

[0038] In operation S3, according to the target values of the first parameter, the second parameter, the third parameter, and the fourth parameter, the magnetic center of the arc-shaped superconducting coil is adjusted to the initial target position.

[0039] In the embodiments of the present invention, for example, by combining swarm intelligence optimization algorithms such as genetic algorithms and particle swarm algorithms, the optimal values of the first parameter, the second parameter, the third parameter, and the fourth parameter can be determined, that is, the target values of the first parameter, the second parameter, the third parameter, and the fourth parameter are determined.

[0040] In the embodiments of the present invention, the setting ranges of the target values of the first parameter, the second parameter, the third parameter, and the fourth parameter are all -0.1 V / m ~ 0.1 V / m. That is, for the DCT type superconducting coil according to the above embodiments, the corresponding target values are determined for the coil parameters m1~m4 based on the genetic algorithm, and the setting ranges of the target values are all set at -0.1 V / m ~ 0.1 V / m.

[0041] Further, after determining the target values of the first parameter, the second parameter, the third parameter, and the fourth parameter, the magnetic center of the arc-shaped superconducting coil is adjusted to the initial target position by adjusting the current distribution of the cross-section of the arc-shaped superconducting coil.

[0042] Figure 4 Schematically shows the current distribution diagram of the cross-section of the arc-shaped superconducting coil according to an embodiment of the present invention.

[0043] It can be understood that, as Figure 4 shown, the cross-section current distribution refers to the type of conductor distribution on the cross-section of the coil controlled by a set of shape parameters, so that the current density is distributed as cos(mθ) on the cross-section of the coil as shown in the coil interface distribution 1 in Figure 4 . Limited by the limited number of coil turns, the conductor distribution cannot fully achieve the current density distribution according to cos(mθ), and can only approach it as much as possible through the shape parameters. Therefore, by determining the target values of the first parameter, the second parameter, the third parameter, and the fourth parameter, the current distribution of the cross-section of the arc-shaped superconducting coil is adjusted, so that the magnetic center of the arc-shaped superconducting coil is adjusted to the initial target position.

[0044] In an embodiment of the present invention, the initial target position is within 0.3 mm from the geometric center of the arc-shaped superconducting coil.

[0045] Based on the above embodiment, the first-stage offset adjustment of the magnetic center of the arc-shaped superconducting coil is completed, and the magnetic center of the arc-shaped superconducting coil is adjusted to within 0.3 mm from the geometric center of the arc-shaped superconducting coil.

[0046] Figure 5 Shows a schematic diagram of the arc-shaped superconducting coil placed in the skeleton wire groove according to an embodiment of the present invention.

[0047] As Figure 5 shown, after completing the above first-stage offset adjustment, the arc-shaped superconducting coil 5 entity is placed on the arc-shaped superconducting coil skeleton 3. The arc-shaped superconducting coil skeleton is used to support the arc-shaped superconducting coil, and the coil is arranged in the wire groove 4 on the skeleton.

[0048] In operation S4, after adjusting the magnetic center of the arc-shaped superconducting coil to the initial target position, the magnetic center is moved to the geometric center of the skeleton by adjusting the depth of the wire groove of the arc-shaped superconducting coil skeleton.

[0049] In an embodiment of the present invention, by adjusting the depth of the wire groove of the arc-shaped superconducting coil skeleton, the magnetic center of the arc-shaped superconducting coil is moved to the geometric center of the skeleton in the form of overall translation of the arc-shaped superconducting coil.

[0050] It can be understood that by adjusting the depth of the arc-shaped superconducting coil skeleton wire groove 4, the magnetic center is moved to the geometric center of the skeleton 3 in the form of the overall translation of the coil conductor, that is, the magnetic center of the superconducting coil is corrected back to the geometric center of the skeleton by mechanical adjustment means.

[0051] Based on the above embodiments, the offset adjustment in the second stage is completed. Through the embodiments of the present application, the magnetic center of the arc-shaped superconducting coil is adjusted to the geometric center of the magnet cross-section by combining coil adjustment and mechanical adjustment, solving the problem of the magnetic center offset of the superconducting coil caused by the arc-shaped structure and eliminating the serious interference to the beam operation in the multi-pole composite magnetic field.

[0052] Those skilled in the art can understand that although the present invention has been shown and described with reference to specific exemplary embodiments of the present invention, those skilled in the art should understand that various changes in form and details can be made to the present invention without departing from the spirit and scope of the present invention defined by the appended claims and their equivalents. Therefore, the scope of the present invention should not be limited to the above embodiments, but should be determined not only by the appended claims but also by the equivalents of the appended claims.

[0053] In the above specific embodiments, the purpose, technical solution and beneficial effects of the present invention are further described in detail. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for adjusting the magnetic center offset of an arc-shaped superconducting coil, characterized in that, Including: Obtain an arc-shaped superconducting coil model to be processed, where the arc-shaped superconducting coil includes multiple parameters; Based on a preset swarm intelligence algorithm, respectively determine the target value of the first parameter, the target value of the second parameter, the target value of the third parameter, and the target value of the fourth parameter among the multiple parameters; According to the target value of the first parameter, the target value of the second parameter, the target value of the third parameter, and the target value of the fourth parameter, adjust the magnetic center of the arc-shaped superconducting coil to the initial target position; After adjusting the magnetic center of the arc-shaped superconducting coil to the initial target position, move the magnetic center to the geometric center of the skeleton by adjusting the depth of the skeleton wire groove of the arc-shaped superconducting coil; Wherein, the arc-shaped superconducting coil skeleton is used to support the arc-shaped superconducting coil.

2. The method for adjusting the magnetic center offset of the arc-shaped superconducting coil according to claim 1, wherein The adjusting the magnetic center of the arc-shaped superconducting coil to the initial target position according to the target value of the first parameter, the target value of the second parameter, the target value of the third parameter, and the target value of the fourth parameter includes: Based on the target value of the first parameter, the target value of the second parameter, the target value of the third parameter, and the target value of the fourth parameter, adjust the magnetic center of the arc-shaped superconducting coil to the initial target position by adjusting the current distribution of the cross-section of the arc-shaped superconducting coil.

3. The method for adjusting the magnetic center offset of the arc-shaped superconducting coil according to claim 2, characterized in that The initial target position is within 0.3 mm from the geometric center of the arc-shaped superconducting coil.

4. The method for adjusting the magnetic center offset of the arc superconducting coil according to claim 1, characterized in that The moving the magnetic center to the geometric center of the skeleton by adjusting the depth of the skeleton wire groove of the arc-shaped superconducting coil includes: By adjusting the depth of the skeleton wire groove of the arc-shaped superconducting coil, the magnetic center of the arc-shaped superconducting coil is moved to the geometric center of the skeleton in the form of overall translation.

5. The method for adjusting the magnetic center offset of the arc-shaped superconducting coil according to claim 1, characterized in that The setting ranges of the target value of the first parameter, the target value of the second parameter, the target value of the third parameter, and the target value of the fourth parameter are all -0.1 V / m to 0.1 V / m.

6. The method for adjusting the magnetic center offset of the arc-shaped superconducting coil according to claim 1, characterized in that The first parameter, the second parameter, the third parameter, and the fourth parameter are respectively the dipole field component, the quadrupole field component, the hexapole field component, and the octupole field component.

7. The method for adjusting the magnetic center offset of the arc superconducting coil according to claim 1, characterized in that The obtaining the arc-shaped superconducting coil model to be processed includes: Based on a preset shape function, determine the arc-shaped superconducting coil model by adjusting multiple parameters of the arc-shaped superconducting coil.

8. The method for adjusting the magnetic center offset of the arc-shaped superconducting coil according to claim 7, characterized in that The fifth parameter, the sixth parameter, the seventh parameter, and the eighth parameter among the multiple parameters are all determined according to the design requirements of the superconducting magnet.

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