Arc-shaped superconducting coil magnetic center offset adjusting method

Abstract

The application provides an arc-shaped superconducting coil magnetic center offset adjusting method, comprising: obtaining an arc-shaped superconducting coil model to be processed, the arc-shaped superconducting coil comprising a plurality of parameters; 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; adjusting the magnetic center of the arc-shaped superconducting coil to an initial target position according to the first parameter target value, the second parameter target value, the third parameter target value and the fourth parameter target value; after adjusting the magnetic center of the arc-shaped superconducting coil to the initial target position, moving the magnetic center to a skeleton geometric center by adjusting the depth of an arc-shaped superconducting coil skeleton slot; wherein the arc-shaped superconducting coil skeleton is used for supporting the arc-shaped superconducting coil.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of superconducting magnet of medical ion therapy accelerator, and particularly relates to a magnetic center offset adjusting method of arc-shaped superconducting coil. BACKGROUND

[0002] In the field of coil dominant superconducting magnet of medical ion therapy accelerator, the coil dominant superconducting magnet is used in medical ion accelerator due to its small size, light weight and multi-pole composite characteristics. However, the arc-shaped structure often causes the magnetic center of the superconducting coil to deviate, that is, the magnetic center of the arc-shaped superconducting coil is often not at the geometric center of the coil section. This will seriously affect the beam operation, therefore, it is urgent to correct the magnetic center of the superconducting coil back through a related method. SUMMARY

[0003] (I) Technical problem to be solved

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

[0005] (II) Technical scheme

[0006] In order to achieve the above purpose, the present application provides a magnetic center offset adjusting method of arc-shaped superconducting coil, comprising: obtaining an arc-shaped superconducting coil model to be processed, the arc-shaped superconducting coil comprising a plurality of parameters; 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; adjusting the magnetic center of the arc-shaped superconducting coil to an initial target position according to the first parameter target value, the second parameter target value, the third parameter target value and the fourth parameter target value; 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 slot 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 scheme, the magnetic center of the arc-shaped superconducting coil is adjusted to the initial target position according to the first parameter target value, the second parameter target value, the third parameter target value and the fourth parameter target value, comprising: based on 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 by adjusting the current distribution of the arc-shaped superconducting coil section.

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

[0009] In the scheme, the magnetic center is moved to the geometric center of the skeleton by adjusting the depth of the skeleton slot of the arc-shaped superconducting coil, comprising: adjusting the depth of the skeleton slot of the arc-shaped superconducting coil, so that the arc-shaped superconducting coil moves the magnetic center of the arc-shaped superconducting coil to the geometric center of the skeleton in the form of overall translation.

[0010] In the scheme, the setting range of the first parameter target value, the second parameter target value, the third parameter target value and the fourth parameter target value is-0.1 V / m~0.1 V / m.

[0011] In the scheme, the first parameter, the second parameter, the third parameter and the fourth parameter are dipole field components, quadrupole field components, sextupole field components and octupole field components respectively.

[0012] In the scheme, the arc-shaped superconducting coil model to be processed is obtained, comprising: based on a preset shape function, adjusting a plurality of parameters of the arc-shaped superconducting coil to determine the arc-shaped superconducting coil model.

[0013] In the scheme, the fifth parameter, the sixth parameter, the seventh parameter and the eighth parameter in the plurality of parameters are determined according to the superconducting magnet design requirements.

[0014] (Three) beneficial effects

[0015] The technical scheme of the embodiment of the application has at least the following beneficial effects:

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

[0017] (2) The method is simple and efficient, and is suitable for various coil dominant superconducting magnets, has strong universality and good practicability. DETAILED DESCRIPTION

[0018] Figure 1 The flowchart of the arc-shaped superconducting coil magnetic center offset adjustment method according to the embodiment of the application is schematically shown;

[0019] Figure 2 The global view of the arc-shaped superconducting coil model according to the embodiment of the application is schematically shown;

[0020] Figure 3 The cross-sectional partial view of the arc-shaped superconducting coil model according to the embodiment of the application is schematically shown;

[0021] Figure 4 The cross-sectional current distribution diagram of the arc-shaped superconducting coil according to the embodiment of the application is schematically shown;

[0022] Figure 5 A schematic diagram showing an arc-shaped superconducting coil placed in a skeleton slot according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0023] To make the objectives, technical solutions and advantages of the present application clearer, further detailed description will be made to the present application in combination with specific embodiments and with reference to the drawings.

[0024] Figure 1 A flow chart of an arc-shaped superconducting coil magnetic center offset adjustment method according to an embodiment of the present application is shown schematically. Figure 2 A global view of an arc-shaped superconducting coil model according to an embodiment of the present application is shown schematically. Figure 3 A cross-sectional partial view of an arc-shaped superconducting coil model according to an embodiment of the present application is shown schematically.

[0025] As shown in Figure 1 , the arc-shaped superconducting coil magnetic center offset adjustment method specifically comprises operations S1-S4.

[0026] In operation S1, an arc-shaped superconducting coil model to be processed is acquired, and the arc-shaped superconducting coil comprises a plurality of parameters.

[0027] According to an embodiment of the present application, in order to perform the first-stage offset adjustment of the magnetic center of the arc-shaped superconducting coil, the structure of the arc-shaped superconducting coil main model and the coil distribution need to be determined first, and then the offset of the magnetic center of the superconducting coil is adjusted by adjusting the coil parameters of the arc-shaped superconducting coil.

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

[0029] It can be understood that the arc-shaped superconducting coil model is determined by a plurality of parameters, for example, can be determined by 8 parameters, wherein the fifth parameter, the sixth parameter, the seventh parameter and the eighth parameter can be the coil layer number, the coil turn number, the coil end length and the coil straight segment length, and the four parameters are all parameters determined according to the superconducting magnet design requirements before the model is established, so that the main structure size of the arc-shaped superconducting coil can be determined.

[0030] Further, 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 sextupole field component and the octupole field component, respectively.

[0031] As shown in Figure 2 and Figure 3 , based on the preset shape function, the arc-shaped superconducting coil model to be processed can be established based on a three-dimensional modeling software according to the above-mentioned 8 parameters, and the coil model is composed of a plurality of coils 5.

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

[0033]

[0034]

[0035] wherein m1~m4, nn, N, L e , L st are determined by a total of 8 parameters, wherein nn, N, L e , L st respectively are the coil layer number, the coil turn number, the coil end length, and the coil straight segment length, which are required to be determined in advance according to the superconducting magnet design requirements (such as the magnetic field value, the effective length, and the deflection angle) before the model is established, so as to determine the main structure size of the DCT superconducting coil. Among them, m1~m4 are respectively the dipole field component, the quadrupole field component, the sextupole field component, and the octupole field component.

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

[0037] In operation S2, based on the preset swarm intelligence algorithm, the first parameter target value, the second parameter target value, the third parameter target value, and the fourth parameter target value are determined respectively.

[0038] In operation S3, 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.

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

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

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

[0042] Figure 4 The arc-shaped superconducting coil cross section current distribution diagram according to the embodiment of the present application is schematically shown.

[0043] It can be understood that, as shown in Figure 4 , the cross section current distribution refers to the conductor distribution class on the coil cross section controlled by a group of shape parameters, so that the current density is cos(mθ) distribution on the coil cross section as shown in Figure 4 , the conductor distribution cannot completely realize the current density according to cos(mθ) distribution due to the limited number of coil turns, and can only be as close as possible by shape parameters. Therefore, by determining the first parameter target value, the second parameter target value, the third parameter target value and the fourth parameter target value, the current distribution of the arc-shaped superconducting coil cross section is adjusted, so that the magnetic center of the arc-shaped superconducting coil is adjusted to the initial target position.

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

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

[0046] Figure 5 The schematic diagram of the arc-shaped superconducting coil placed in the skeleton wire slot according to the embodiment of the present application is shown.

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

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

[0049] In the embodiment of the present application, by adjusting the depth of the arc-shaped superconducting coil skeleton wire slot, the arc-shaped superconducting coil is moved to the skeleton geometric center in the form of whole translation.

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

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

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

[0053] The above specific embodiments further detail the purpose, technical solutions and beneficial effects of the present application, and it should be understood that the above are only specific embodiments of the present application and are not intended to limit the present application, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method of adjusting the magnetic center offset of an arc-shaped superconducting coil, characterized by, The method comprises the following steps: acquiring an arc-shaped superconducting coil model to be processed, the arc-shaped superconducting coil comprising a plurality of parameters; 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 respectively based on a preset swarm intelligence algorithm; adjusting a magnetic center of the arc-shaped superconducting coil to an initial target position according to the first parameter target value, the second parameter target value, the third parameter target value and the fourth parameter target value; after adjusting the magnetic center of the arc-shaped superconducting coil to the initial target position, moving the magnetic center to a skeleton geometric center by adjusting a depth of a skeleton wire slot of the arc-shaped superconducting coil; wherein the skeleton of the arc-shaped superconducting coil is used to support the arc-shaped superconducting coil; the adjusting of the magnetic center of the arc-shaped superconducting coil to the initial target position according to the first parameter target value, the second parameter target value, the third parameter target value and the fourth parameter target value comprises: adjusting the magnetic center of the arc-shaped superconducting coil to the initial target position by adjusting a current distribution of a cross section of the arc-shaped superconducting coil based on the first parameter target value, the second parameter target value, the third parameter target value and the fourth parameter target value; the moving of the magnetic center to the skeleton geometric center by adjusting the depth of the skeleton wire slot of the arc-shaped superconducting coil comprises: adjusting the depth of the skeleton wire slot of the arc-shaped superconducting coil so that the arc-shaped superconducting coil moves the magnetic center of the arc-shaped superconducting coil to the skeleton geometric center in the form of an overall translation.

2. The arc-shaped superconducting coil magnetic center shift adjustment method of claim 1, wherein, The initial target position is within a range of 0.3 mm from a geometric center of the arc-shaped superconducting coil.

3. The arc-shaped superconducting coil magnetic center shift adjustment method of claim 1, wherein, The first parameter target value, the second parameter target value, the third parameter target value and the fourth parameter target value are all set in a range of -0.1 V / m to 0.1 V / m.

4. The arc-shaped superconducting coil magnetic center shift adjustment method of claim 1, wherein, The first parameter, the second parameter, the third parameter and the fourth parameter are respectively a dipole field component, a quadrupole field component, a sextupole field component and an octupole field component.

5. The arc-shaped superconducting coil magnetic center shift adjustment method of claim 1, wherein, The acquiring of the arc-shaped superconducting coil model to be processed comprises: determining the arc-shaped superconducting coil model by adjusting a plurality of parameters of the arc-shaped superconducting coil based on a preset shape function.

6. The arc-shaped superconducting coil magnetic center shift adjustment method of claim 5, wherein, The fifth parameter, the sixth parameter, the seventh parameter and the eighth parameter in the plurality of parameters are all determined according to superconducting magnet design requirements.

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