Magnetic field optimization method of discretized cosine superconducting coil
By normalizing and optimizing the discrete cosine superconducting coil, it is simplified into a two-layer coil structure, using the outermost coil to adjust the current distribution, combining genetic algorithms and particle swarm algorithms, the problems of complexity and low efficiency of magnetic field optimization in miniaturized medical ion accelerators are solved, and efficient optimization of magnetic field uniformity is achieved.
Patent Information
- Application Number
- CN202510719992.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-30
- Publication Date
- 2025-08-08
AI Technical Summary
In the prior art, the magnetic field optimization process of discrete cosine superconducting magnets for miniaturized medical ion accelerators is complex and inefficient, making it difficult to generate a uniform magnetic field within a larger aperture.
By normalizing the discrete cosine superconducting coil, it is simplified into a two-layer coil structure, the outermost coil is used to adjust the current distribution of the coil cross-section, and the magnetic field uniformity is optimized by combining genetic algorithms and particle swarm algorithms to simplify the modeling process and improve optimization efficiency.
Fast and efficient magnetic field optimization is achieved, and the magnetic field uniformity reaches the order of one hundred thousand, improving the magnetic field optimization efficiency.
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Figure CN120449506A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the technical field of superconducting magnets for medical ion therapy accelerators, and in particular to a magnetic field optimization method for a discretized cosine superconducting coil. Background Art
[0002] The discrete cosine superconducting magnets used in miniaturized medical ion accelerators typically require a uniform magnetic field within a large aperture. This necessitates the use of a multi-layered, nested structure of discrete cosine superconducting coils to generate a sufficient magnetic field. This necessitates magnetic field optimization of the discrete cosine superconducting coils. Existing techniques for optimizing magnetic field uniformity typically involve modeling all the multiple layers of coils before optimizing. This approach is complex and slow. Summary of the Invention
[0003] In view of the above problems, an embodiment of the present disclosure provides a magnetic field optimization method for a discretized cosine superconducting coil.
[0004] One aspect of the present disclosure provides a magnetic field optimization method for a discretized cosine superconducting coil, comprising: obtaining a discretized cosine superconducting coil, the discretized cosine superconducting coil comprising an outermost coil and remaining coils, the remaining coils comprising a multi-layer coil; performing a normalization operation on the remaining coils to obtain a normalized coil, the normalized coil representing a coil layer in the multi-layer coil; and performing magnetic field optimization on the normalized discretized cosine superconducting coil based on the outermost coil to obtain a discretized cosine superconducting coil after magnetic field optimization.
[0005] According to an embodiment of the present disclosure, normalizing the remaining layers of coils to obtain a normalized coil includes: removing coils from the remaining layers of coils until only one layer of target coil remains in the remaining layers of coils; and adjusting the current of the target coil according to the magnetic field strength of the discretized cosine superconducting coil to obtain the normalized coil.
[0006] According to an embodiment of the present disclosure, the size of the target coil is equal to an average of sizes of the multi-layer coils.
[0007] According to an embodiment of the present disclosure, performing magnetic field optimization on a normalized discretized cosine superconducting coil based on an outermost coil includes: adjusting a coil cross-sectional current distribution of the discretized cosine superconducting coil based on the outermost coil; and optimizing the magnetic field uniformity of the normalized discretized cosine superconducting coil based on the coil cross-sectional current distribution.
[0008] According to an embodiment of the present disclosure, adjusting the coil cross-sectional current distribution of the discretized cosine superconducting coil according to the outermost coil includes adjusting the coil cross-sectional current distribution of the discretized cosine superconducting coil according to the optimized parameters of the outermost coil.
[0009] According to an embodiment of the present disclosure, the magnetic field uniformity is at the order of one hundred thousandth.
[0010] According to an embodiment of the present disclosure, adjusting the coil cross-sectional current distribution of the discretized cosine superconducting coil includes: adjusting the coil cross-sectional current distribution of the discretized cosine superconducting coil using a genetic algorithm and / or a particle swarm algorithm according to optimization parameters.
[0011] According to an embodiment of the present disclosure, the magnetic field optimization parameters include: multipole field components, the number of turns of the outermost coil, and the end length of the outermost coil.
[0012] According to an embodiment of the present disclosure, the current load rate of the discretized cosine superconducting coil is less than or equal to 70%.
[0013] According to an embodiment of the present disclosure, a discretized cosine superconducting coil is applied to a discretized cosine type medical ion accelerator.
[0014] According to a magnetic field optimization method for a discretized cosine superconducting coil provided in an embodiment of the present disclosure, by simplifying the multi-layer coils and regulating the overall magnetic field quality according to the outermost coil, fast and efficient magnetic field optimization iteration can be achieved, greatly improving the efficiency of magnetic field optimization. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above contents and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:
[0016] Figure 1 A flowchart of a method for optimizing a magnetic field of a discretized cosine superconducting coil according to an embodiment of the present disclosure is schematically shown;
[0017] Figure 2 Schematically shows a structural diagram of a discretized cosine superconducting coil according to an embodiment of the present disclosure;
[0018] Figure 3 The structure of the outermost coil and the remaining coils in the discretized cosine superconducting coil according to an embodiment of the present disclosure is schematically shown.
[0019] [Description of Reference Numerals]
[0020] 1-Length of the straight section of the coil; 2-Length of the end of the coil; 3-Remaining layers of coils; 4-Number of turns of the outermost coil; 5-Direction of current distribution in the coil cross section. DETAILED DESCRIPTION
[0021] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.
[0022] It should be noted that in the drawings or descriptions of the specification, similar or identical parts use the same figure numbers. The technical features in the various embodiments exemplified in the specification can be freely combined to form new solutions without conflict. In addition, each claim can be used as an embodiment alone or the technical features in each claim can be combined as a new embodiment. In the drawings, the shape or thickness of the embodiment can be expanded and simplified or conveniently indicated. Furthermore, the elements or implementations not shown or described in the drawings are forms known to ordinary technicians in the relevant technical field. In addition, although this article may provide demonstrations of parameters containing specific values, it should be understood that the parameters do not need to be exactly equal to the corresponding values, but can be approximated to the corresponding values within an acceptable error tolerance or design constraint.
[0023] Unless there are technical obstacles or contradictions, the above-mentioned various embodiments of the present disclosure can be freely combined to form additional embodiments, and these additional embodiments are all within the protection scope of the present disclosure.
[0024] Although the present disclosure is described in conjunction with the accompanying drawings, the embodiments disclosed in the drawings are intended to illustrate preferred embodiments of the present disclosure and are not to be construed as limiting the present disclosure. The dimensional ratios in the drawings are merely illustrative and are not to be construed as limiting the present disclosure.
[0025] Although some embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined in the claims and their equivalents.
[0026] Figure 1 The flowchart of the magnetic field optimization method of the discretized cosine superconducting coil according to the embodiment of the present disclosure is schematically shown.
[0027] like Figure 1 As shown, an embodiment of the present disclosure provides a magnetic field optimization method for a discretized cosine superconducting coil, including operations S110 to S130.
[0028] In operation S110 , a discretized cosine superconducting coil is obtained, where the discretized cosine superconducting coil includes an outermost coil and remaining coils.
[0029] In some embodiments, the discretized cosine coil of the embodiment of the present disclosure can be applied to a discretized cosine type medical ion accelerator.
[0030] Figure 2 The structure of a discretized cosine superconducting coil according to an embodiment of the present disclosure is schematically shown.
[0031] like Figure 2As shown, for the discretized cosine superconducting coil, its structure can be described by a set of shape functions (1):
[0032] (1)
[0033] in,
[0034] The coil distribution is determined by 10 parameters: m1 to m4, nn, N, N_out, Le, Le_out, and Lst. Here, z represents the independent variable, θ represents the angle variable, i represents an integer index, and N represents a normalization constant. m1 to m4, nn, N, N_out, Le, Le_out, and Lst represent the multipole field component, the number of coil layers, the number of turns in the inner multilayer coil, the number of turns in the outermost coil (4), the coil end length (2), the outermost coil end length (1), and the coil straight segment length (1). The four parameters, namely, the number of coil layers, the number of turns in the inner multilayer coil, the coil end length (2), and the coil straight segment length (1), must be determined in advance based on the superconducting magnet design requirements (such as magnetic field value, effective length, and deflection angle) before model establishment to determine the main structural dimensions of the discretized cosine superconducting coil.
[0035] Furthermore, when discretizing cosine superconducting coil finite element modeling, parameterized 3D modeling can be performed on the outermost coil, including key components such as coil end dimensions and cross-sectional current density distribution. After defining the respective variation ranges, these variations are simultaneously applied during the optimization iteration process, aiming to find the optimal solution within a large parameter space.
[0036] The embodiment of the present disclosure establishes a full-scale model of the coil and adjusts the discretized cosine superconducting coil to meet the design requirements.
[0037] In operation S120 , a normalization operation is performed on the remaining layer coils to obtain normalized coils.
[0038] Figure 3 The structure of the outermost coil and the remaining coils in the discretized cosine superconducting coil according to an embodiment of the present disclosure is schematically shown.
[0039] In some embodiments, coils in the remaining layers of coils may be removed until only one target coil remains in the remaining layers of coils, and then the current of the target coil is adjusted according to the magnetic field strength of the discretized cosine superconducting coil to obtain the normalized coil.
[0040] like Figure 3As shown, in the disclosed embodiment, a multi-layered, nested discretized cosine superconducting coil is selected. Except for the outermost coil, the remaining layers within the coil are simplified into a single target coil. The target coil size can be equal to the average size of the multi-layer coils. The current in the simplified coil is then adjusted to ensure that the main magnetic field value of the simplified discretized cosine superconducting coil remains constant.
[0041] The method of this embodiment can directly simplify a multi-layer coil into two layers of coils (i.e., the outermost coil and the remaining layers of coils), greatly reducing the modeling difficulty and significantly improving the single optimization rate. At the same time, the method of this embodiment can optimize the magnetic field uniformity of the superconducting coil to the order of one hundred thousandth.
[0042] In operation S130 , magnetic field optimization is performed on the discretized cosine superconducting coil after the normalization operation according to the outermost coil to obtain a discretized cosine superconducting coil after magnetic field optimization.
[0043] In some embodiments, the coil cross-sectional current distribution of the discretized cosine superconducting coil can be adjusted based on the outermost coil, and the magnetic field uniformity of the discretized cosine superconducting coil after normalization can be optimized based on the coil cross-sectional current distribution.
[0044] For example, the current distribution across the coil cross section of the discretized cosine superconducting coil can be adjusted based on the optimization parameters of the outermost coil. The optimization parameters include the multipole field component, the number of turns of the outermost coil, and the end length of the outermost coil. The multipole field component can be, for example, a dipole field component, a quadrupole field component, a sextupole field component, or an octupole field component.
[0045] The adjustment range of the optimization parameters is shown in Table (1).
[0046] Table (1)
[0047] parameter illustrate Parameter setting range m1 Dipolar field component -0.1~0.1 m2 quadrupole field components -0.1~0.1 m3 Sextupole field component -0.1~0.1 m4 Octupole field component -0.1~0.1 N_out Number of turns of the outermost coil 18~25 Le_out Length of outermost coil end 100~150
[0048] First, by adjusting the number of turns N_out of the outermost coil and the length Le_out of the outermost coil end, the effective length of the superconducting coil is ensured to meet the design requirements. Among them, the current load rate in the superconducting wire should be kept within 70%.
[0049] Then, keeping the remaining layers of coils unchanged, only the four parameters of the outermost coil, the dipole field component to the octupole field component m1~m4, are optimized by combining various optimization methods such as genetic algorithm and particle swarm algorithm to optimize the magnetic field uniformity of the superconducting coil. Adjusting the parameters of the dipole field component to the octupole field component m1~m4 can change the current distribution in the coil cross section, thereby achieving the optimization of the magnetic field uniformity.
[0050] Please continue reading Figure 3, the coil cross-section current distribution direction 5 refers to the current density being discrete cosine distribution on the coil cross-section by controlling the conductor distribution on the coil cross-section through a set of shape parameters. Due to the limited number of coil turns, the conductor distribution cannot fully realize the current density distribution and can only be as close as possible through the shape parameters.
[0051] In this way, the reliance of complex modeling on high computing power and long time during the magnetic field optimization process is avoided, and the magnetic field performance of the entire discretized cosine superconducting coil is controlled by multiple optimization parameters of the outermost coil, enabling fast and efficient magnetic field optimization iteration.
[0052] It should be understood that the specific order or hierarchy of steps in the disclosed processes is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of the present disclosure. The accompanying method claims present elements of the various steps in an exemplary order and are not intended to be limited to a specific order or hierarchy.
[0053] It should also be noted that directional terms such as "upper," "lower," "front," "back," "left," and "right" mentioned in the embodiments are merely references to the directions in the accompanying drawings and are not intended to limit the scope of protection of this disclosure. Throughout the drawings, identical elements are represented by identical or similar reference numerals. Conventional structures or configurations that may cause confusion in understanding this disclosure will be omitted. Furthermore, the shapes, sizes, and positional relationships of the components in the drawings do not reflect their actual sizes, proportions, or actual positional relationships.
[0054] In the foregoing detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that embodiments of the claimed subject matter require more features than are expressly recited in each claim. On the contrary, as reflected in the appended claims, the disclosure comprises less than all features of any individual disclosed embodiment. The appended claims are therefore hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the disclosure.
[0055] In addition, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present disclosure, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. With respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", as explained in terms of "including" used as a transitional word in the claims. Any term "or" used in the specification of the claims is intended to mean "non-exclusive or".
[0056] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the scope of protection of the present disclosure.
Claims
1. A magnetic field optimization method for a discretized cosine superconducting coil, characterized in that: include: Obtaining a discrete cosine superconducting coil, wherein the discrete cosine superconducting coil includes an outermost coil and remaining coils, wherein the remaining coils include multiple layers of coils; performing a normalization operation on the remaining layers of coils to obtain a normalized coil, wherein the normalized coil represents a layer of coils in the multi-layer coil; The magnetic field of the discretized cosine superconducting coil after the normalization operation is optimized according to the outermost coil to obtain a discretized cosine superconducting coil after the magnetic field optimization.
2. The method according to claim 1, characterized in that The normalizing operation is performed on the remaining layers of coils to obtain normalized coils, comprising: removing coils from the remaining layers of coils until a target coil remains in the remaining layers of coils; The current of the target coil is adjusted according to the magnetic field strength of the discretized cosine superconducting coil to obtain the normalized coil.
3. The method according to claim 2, characterized in that The size of the target coil is equal to an average of sizes of the multi-layer coils.
4. The method according to claim 1, wherein The performing of magnetic field optimization on the discretized cosine superconducting coil after the normalization operation according to the outermost coil includes: adjusting a coil cross-sectional current distribution of the discretized cosine superconducting coil according to the outermost coil; According to the coil cross-sectional current distribution, the magnetic field uniformity of the discretized cosine superconducting coil after the normalization operation is optimized.
5. The method according to claim 4, characterized in that The step of adjusting the coil cross-sectional current distribution of the discretized cosine superconducting coil according to the outermost coil comprises: The coil cross-sectional current distribution of the discretized cosine superconducting coil is adjusted according to the optimized parameters of the outermost coil.
6. The method according to claim 4, characterized in that The magnetic field uniformity is at the order of one part per hundred thousand.
7. The method according to claim 5, characterized in that The adjusting the coil cross-sectional current distribution of the discretized cosine superconducting coil comprises: According to the optimization parameters, a genetic algorithm and / or a particle swarm algorithm is used to adjust the coil cross-sectional current distribution of the discretized cosine superconducting coil.
8. The method according to claim 5, characterized in that The magnetic field optimization parameters include: multipole field components, the number of turns of the outermost coil and the end length of the outermost coil.
9. The method according to claim 1, characterized in that The current load rate of the discrete cosine superconducting coil is less than or equal to 70%.
10. The method according to claim 1, characterized in that The discrete cosine superconducting coil is applied to a discrete cosine type medical ion accelerator.