A modular method and device for an all-permanent-magnet electron cyclotron resonance ion source

Abstract

The present invention relates to a modular method and device for an all-permanent-magnet electron cyclotron resonance ion source, which includes: an ion source magnet composed of a first axial magnet, a second axial magnet, and a radial magnet, with the overall inner radius of the ion source being R0; the first axial magnet and the second axial magnet have opposite magnetization directions, and the first axial magnet and the second axial magnet are composed of magnetic rings with different radii, different axial thicknesses, and capable of providing an axial magnetic field; the first axial magnet and the second axial magnet are divided into multiple groups according to the axial thickness; the first axial magnet and the second axial magnet are divided into multiple groups according to the radial thickness; the radial magnet adopts a HALBACH structure with three numbers of circumferential magnetic blocks and is divided into multiple groups according to the axial thickness; the radial magnet, the first axial magnet, and the second axial magnet are all divided into n times 12 magnetic blocks along the angular direction; according to the performance requirements of the ion source, the first axial magnet, the second axial magnet, and the radial magnet with three numbers of circumferential magnetic blocks are arranged and combined according to n times the axial thickness d and the radial thickness r to form a complete ion source magnet.

Description

Technical Field

[0001] The present invention relates to the technical field of ion source of ion accelerators, and particularly to a modular method and device for a fully permanent magnet electron cyclotron resonance ion source. Background Art

[0002] When developing a traditional fully permanent magnet ion source, it is necessary to design a corresponding magnetic field according to the performance, then design the corresponding mechanical specifications of the magnetic ring according to the required magnetic field, and then carry out subsequent procurement, production and processing steps according to the mechanical drawings. Although the required performance ion source can be successfully developed using this traditional R & D idea, the R & D of each ion source requires re-designing and calculating manufacturing, which also causes waste of R & D resources. If the ion source can be decomposed into different types of modules, only the modules are produced during production, and then different specifications of modules are assembled into a complete ion source magnet according to the performance requirements of the required ion source, the time cost and economic cost from R & D production to finished product will be greatly reduced. Summary of the Invention

[0003] Aiming at the above problems, the purpose of the present invention is to provide a modular method and device for a fully permanent magnet electron cyclotron resonance ion source, which solves the problem of "one design for one ion source and one specification for one ion source" in the R & D and manufacturing process of the fully permanent magnet electron cyclotron resonance ion source and reduces the cost.

[0004] To achieve the above purpose, the present invention adopts the following technical solutions: A modular method for a fully permanent magnet electron cyclotron resonance ion source, which includes: an ion source magnet is composed of a first axial magnet, a second axial magnet and a radial magnet, and the radial magnet is located between the first axial magnet and the second axial magnet, and the overall inner radius of the ion source is R0; the first axial magnet and the second axial magnet have opposite magnetization directions, and the first axial magnet and the second axial magnet are composed of a combination of magnetic rings with different radii, different axial thicknesses and capable of providing axial magnetic fields; the first axial magnet and the second axial magnet are divided into multiple groups according to the axial thickness, and the number of divided groups is n times the axial thickness d, where n is an integer; the radial magnet adopts a HALBACH structure with three circumferential magnet block numbers and is divided into multiple groups according to the axial thickness, and the number of divided groups is n times the axial thickness d; the radial magnet, the first axial magnet and the second axial magnet are all divided into 12n magnetic blocks along the angular direction; according to the performance requirements of the ion source, the first axial magnet, the second axial magnet and the radial magnet are arranged and combined according to n times the axial thickness d to form a complete ion source magnet.

[0005] Further, the first axial magnet a and the second axial magnet b are respectively set according to the radius; the corresponding radii of the first axial magnet a and the second axial magnet b are R0 + r, R0 + 2r and R0 + 3r respectively, and r is the radial thickness of the magnetic ring.

[0006] Furthermore, the three circumferential magnet blocks used in the radial magnet c are 12 pieces, 24 pieces, or 36 pieces respectively.

[0007] Furthermore, the magnetic ring providing the axial magnetic field is segmented according to an axial thickness d ≤ 50 mm, and the axial thickness of the axial magnet is a multiple of d.

[0008] Furthermore, the magnetic ring providing the axial magnetic field is segmented according to a radial thickness r ≤ 50 mm, and the radial thickness of the axial magnet is a multiple of r.

[0009] Furthermore, the overall inner radius of the ion source is: 50 mm ≥ R0 ≥ 20 mm.

[0010] Furthermore, for light ions and multi-ions with low charge states, the outer diameter of the magnet is R0 + 50 mm; for ions from light ions to heavier ions and ions with medium and high charge states, the outer diameter of the magnet is selected as R0 + 50 + 50 mm; for high charge state ions of heavy ions, the outer diameter of the magnet is selected as R0 + 50 + 50 + 50 mm.

[0011] A modular device of a fully permanent magnet electron cyclotron resonance ion source, which includes: a first axial magnet, a second axial magnet, and a radial magnet; the ion source magnet is composed of the first axial magnet, the second axial magnet, and the radial magnet, and the radial magnet is located between the first axial magnet and the second axial magnet; the first axial magnet and the second axial magnet have opposite magnetization directions, and the first axial magnet and the second axial magnet are composed of a combination of magnetic rings with different radii, different axial thicknesses, and capable of providing an axial magnetic field; the first axial magnet and the second axial magnet are segmented into multiple groups according to the axial thickness, and the number of segmented groups is n times the axial thickness d, where n is an integer; the radial magnet adopts a HALBACH structure with three circumferential magnet block numbers and is segmented into multiple groups according to the axial thickness, and the number of segmented groups is n times the axial thickness d; the radial magnet, the first axial magnet, and the second axial magnet are all segmented into 12n magnetic blocks along the angular direction; according to the performance requirements of the ion source, the first axial magnet, the second axial magnet, and the radial magnet are arranged and combined according to n times the axial thickness d to form a complete ion source magnet.

[0012] Furthermore, the magnetic ring providing the axial magnetic field is segmented according to an axial thickness d ≤ 50 mm, and the axial thickness of the axial magnet is a multiple of d.

[0013] Furthermore, the magnetic ring providing the axial magnetic field is segmented according to a radial thickness r ≤ 50 mm, and the radial thickness of the axial magnet is a multiple of r.

[0014] Due to the above technical solutions adopted by the present invention, it has the following advantages:

[0015] 1. The present invention can simplify the design process of ion sources with different performances. The magnets of ion sources with different performances are divided into standard modules, and a complete ion source magnet can be formed through the arrangement and combination of the modules.

[0016] 2. The modular design adopted by the present invention is particularly suitable for commercial mass production. Only standard modules and sub-modules need to be produced, which can greatly reduce the R & D cost.

[0017] 3. The ion source fabricated by the present invention is applicable to all-permanent-magnet electron cyclotron resonance ion sources from 2.45 GHz to 18 GHz, and is applicable to most ion accelerators such as ion beam cancer therapy and material irradiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic structural diagram of an ion source in an embodiment of the present invention;

[0019] Figure 2a is a schematic diagram of the radial arrangement of a single group of the first axial magnet in an embodiment of the present invention;

[0020] Figure 2b is a schematic diagram of the axial cross-section of a single group of the first axial magnet in an embodiment of the present invention;

[0021] Figure 3 is a schematic diagram of the radial arrangement of a single group of the second axial magnet in an embodiment of the present invention;

[0022] Figure 4a is a schematic diagram of the radial double-group arrangement of the first axial magnet in an embodiment of the present invention;

[0023] Figure 4b is a schematic cross-sectional diagram of the axial single-group and radial double-group arrangement of the first axial magnet in an embodiment of the present invention;

[0024] Figure 4c is a schematic cross-sectional diagram of the axial double-group and radial double-group arrangement of the first axial magnet in an embodiment of the present invention;

[0025] Figure 5 is a schematic diagram of the radial double-group arrangement of the second axial magnet in an embodiment of the present invention;

[0026] Figure 6a is a schematic diagram of the radial triple-group arrangement of the first axial magnet in an embodiment of the present invention;

[0027] Figure 6b is a schematic cross-sectional diagram of the axial single-group and radial triple-group arrangement of the first axial magnet in an embodiment of the present invention;

[0028] Figure 6c is a schematic cross-sectional diagram of the axial double-group and radial triple-group arrangement of the first axial magnet in an embodiment of the present invention;

[0029] Figure 6d It is a schematic cross-sectional view of the arrangement of three groups axially and three groups radially of the first axial magnet in an embodiment of the present invention;

[0030] Figure 7 It is a schematic diagram of the radial arrangement of three groups of the second axial magnet in an embodiment of the present invention. The second axial magnet can be combined in the form of Figure 6b , 6c , 6d;

[0031] Figure 8a It is a schematic cross-sectional view of the axial arrangement of three groups of the radial magnet in an embodiment of the present invention;

[0032] Figure 8b It is a schematic diagram of the radial arrangement of the radial magnet in an embodiment of the present invention. Detailed implementation manners

[0033] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0034] It should be noted that the terms used herein are only for describing the specific implementation manners and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of the described features, steps, operations, devices, components and / or their combinations.

[0035] In order to solve the problem of "one design for one ion source and one specification for one ion source" in the research, development and manufacturing of all-permanent-magnet electron cyclotron resonance ion sources, the modular all-permanent-magnet electron cyclotron resonance ion source provided by the present invention decomposes the traditional all-permanent-magnet electron cyclotron resonance ion sources with low charge states, medium charge states and higher charge states into several modules. By combining different forms of modules, a complete ion source magnet suitable for generating low charge states, medium charge states and high charge states can be formed. The magnetic field of the electron cyclotron resonance ion source is generated by an axial magnetic field and a radial multipole magnetic field. According to the materials used to generate the magnetic field, the ion source magnet can be divided into electromagnetic coils and permanent magnet rings. Whether it is the axial magnetic field or the radial magnetic field, whether it is a wire coil or a permanent magnet ring, a larger wire coil or permanent magnet ring can always be decomposed into a form composed of two or more wire coils or permanent magnet rings combined. The present invention decomposes the all-permanent-magnet electron cyclotron resonance ion source in the form of modules. During manufacturing, only a large number of modules need to be produced, and then assembled into different ion source finished products according to the required ion source performance requirements.

[0036] In one embodiment of the present invention, a modular method for an all-permanent-magnet electron cyclotron resonance ion source is provided.

[0037] In this embodiment, the method includes the following steps:

[0038] 1) Divide the ion source magnet into two categories: axial magnets and radial magnets; the ion source magnet is composed of a first axial magnet a, a second axial magnet b and a radial magnet c, and the radial magnet c is located between the first axial magnet a and the second axial magnet b. The overall inner radius of the ion source is R0, as Figure 1 shown;

[0039] 2) Classification of axial magnet modules. The first axial magnet a and the second axial magnet b have opposite magnetization directions. The first axial magnet a is composed of a combination of magnetic rings with three different radii and three different axial thicknesses and capable of providing an axial magnetic field, and the second axial magnet b is the same; the magnetization direction of the first axial magnet a can be rotated by 180 degrees. Similarly, the second axial magnet b is also rotated by 180 degrees accordingly and has the opposite magnetization direction to the first axial magnet a;

[0040] 3) Divide the first axial magnet a and the second axial magnet b into multiple groups according to the axial thickness. The number of divided groups is n times the axial thickness d, where n is an integer; preferably, 1≤n≤3;

[0041] 4) The radial magnet c adopts a HALBACH structure with three numbers of circumferential magnetic blocks and is divided into multiple groups according to the axial thickness. The number of divided groups is n times the axial thickness d;

[0042] 5) Divide the radial magnet c, the first axial magnet a and the second axial magnet b into 12n magnetic blocks along the angular direction;

[0043] 6) According to the performance requirements of the ion source, the first axial magnet a, the second axial magnet b, and the radial magnet c are arranged and combined according to n times the axial thickness d to form a complete ion source magnet.

[0044] In the above step 2), for the first axial magnet a and the second axial magnet b, they can be divided into three magnet ring specifications of 1a, 2a, and 3a according to their radii, and there are corresponding three magnet ring specifications of 1b, 2b, and 3b, with the corresponding radii being R0 + r, R0 + 2r, and R0 + 3r respectively, where r is the radial thickness of the magnet ring, as Figures 2a to 7 shown.

[0045] The division methods of various specifications of magnet rings include but are not limited to dividing them according to their axial thickness with the magnetization direction vertically upward or downward.

[0046] In the above step 4), as Figure 8a , Figure 8b shown, the three numbers of circumferential magnetic blocks used for the radial magnet c are 12, 24, or 36 respectively. Preferably, the radial magnet c uses a radial hexapole magnetic field.

[0047] In the above embodiments, the magnet rings providing the axial magnetic field are divided according to the axial thickness d ≤ 50 mm, and the axial thickness of the axial magnet is a multiple of d.

[0048] In the above embodiments, the magnet rings providing the axial magnetic field are divided according to the radial thickness r ≤ 50 mm, and the radial thickness of the axial magnet is a multiple of r. Generally, for an ion source with a working frequency of 2.45 GHz - 18 GHz, the maximum radial thickness of its axial magnet does not exceed 250 mm, that is, the superposition of 5 radial modules.

[0049] In the above step 5), for the axial magnet, it is divided into 12, 24, or 36 magnetic blocks along the angular direction; for the radial magnet, it is divided into n times 12 magnetic blocks along the angular direction.

[0050] In the above embodiments, the inner radius of the whole ion source is: 50 mm ≥ R0 ≥ 20 mm. For light ions and multi - ions with low charge states, the outer diameter of the magnet is R0 + 50 mm; for ions from light ions to heavier ions and ions with medium and higher charge states, the outer diameter of the magnet is selected as R0 + 50 + 50 mm; for high - charge - state ions of heavy ions, the outer diameter of the magnet is selected as R0 + 50 + 50 + 50 mm. Through the modular ring - shaped division of the present invention, magnet rings not exceeding 3r can be nested in the radial direction according to the required performance of the ion source.

[0051] In the above embodiments, according to the specifications of magnetic materials produced by existing magnetizers and permanent magnetic material suppliers in the current market, the axial magnetic ring can be divided axially with the axial thickness not greater than 50 mm. For those with an axial thickness ≤ 50 mm, no axial cutting is required; for 50 mm ≤ axial thickness ≤ 100 mm, it can be axially divided into a form of two groups of magnetic rings stacked; for those with an axial thickness > 100 mm, axial division is carried out in multiples of d ≤ 50 mm. Generally, for ion sources with a frequency range of 2.45 GHz - 18 GHz, the axial thickness of the axial permanent magnet does not exceed 150 mm. In this way, for light ions and low-charge-state ion sources with relatively low requirements for axial magnetic field performance, a module with an axial thickness of d can meet the requirements; similarly, the superposition of 2d axial modules represents ion sources with medium and higher charge states from light ions to heavier ions, while the superposition of 3d axial modules represents high-charge-state ion sources of heavier ions.

[0052] In summary, the permanent magnet electron cyclotron resonance ion source magnet manufactured by using the present invention can greatly save costs and streamline the production process, and is especially suitable for commercial ion accelerators, such as ion beam cancer treatment, material irradiation, etc.

[0053] In an embodiment of the present invention, a modular device for a permanent magnet electron cyclotron resonance ion source is provided, which includes: a first axial magnet, a second axial magnet, and a radial magnet;

[0054] The ion source magnet is composed of the first axial magnet, the second axial magnet, and the radial magnet, and the radial magnet is located between the first axial magnet and the second axial magnet;

[0055] The first axial magnet and the second axial magnet have opposite magnetization directions, and the first axial magnet and the second axial magnet are each composed of a combination of magnetic rings with different radii, different axial thicknesses, and capable of providing an axial magnetic field;

[0056] The first axial magnet and the second axial magnet are divided into multiple groups according to the axial thickness, and the number of divided groups is n times the axial thickness d, where n is an integer;

[0057] The radial magnet adopts a HALBACH structure with three numbers of circumferential magnetic blocks and is divided into multiple groups according to the axial thickness, and the number of divided groups is n times the axial thickness d;

[0058] The radial magnet, the first axial magnet, and the second axial magnet are all divided into 12n magnetic blocks along the angular direction;

[0059] According to the performance requirements of the ion source, the first axial magnet, the second axial magnet, and the radial magnet are arranged and combined according to n times the axial thickness d to form a complete ion source magnet.

[0060] In the above embodiments, the magnetic ring providing the axial magnetic field is divided according to an axial thickness d ≤ 50 mm, and the axial thickness of the axial magnet is a multiple of d.

[0061] In the above embodiments, the magnetic ring providing the axial magnetic field is divided according to a radial thickness r ≤ 50 mm, and the radial thickness of the axial magnet is a multiple of r.

[0062] The device provided in this embodiment is based on the above method embodiments. For the specific process and detailed content, please refer to the above embodiments and will not be elaborated here.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. However, such modifications or replacements 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 modular method for a fully permanent magnet electron cyclotron resonance ion source, characterized in that, Including: An ion source magnet is composed of a first axial magnet, a second axial magnet and a radial magnet, and the radial magnet is located between the first axial magnet and the second axial magnet. The overall inner radius of the ion source is R0. The first axial magnet and the second axial magnet have opposite magnetization directions. The first axial magnet and the second axial magnet are composed of combinations of magnetic rings with different radii, different axial thicknesses and capable of providing axial magnetic fields. The first axial magnet and the second axial magnet are divided into multiple groups according to the axial thickness. The number of divided groups is n times the axial thickness d, where n is an integer. The radial magnet adopts a HALBACH structure with three numbers of circumferential magnetic blocks and is divided into multiple groups according to the axial thickness. The number of divided groups is n times the axial thickness d. The radial magnet, the first axial magnet and the second axial magnet are all divided into 12n magnetic blocks along the angular direction. According to the performance requirements of the ion source, the first axial magnet, the second axial magnet and the radial magnet are arranged and combined according to n times the axial thickness d to form a complete ion source magnet.

2. The modular method of the all-permanent-magnet electron cyclotron resonance ion source according to claim 1, characterized in that The first axial magnet a and the second axial magnet b are set according to the radius respectively. The corresponding radii of the first axial magnet a and the second axial magnet b are R0 + r, R0 + 2r and R0 + 3r respectively, where r is the radial thickness of the magnetic ring.

3. The modular method of the all-permanent-magnet electron cyclotron resonance ion source according to claim 1, wherein The three numbers of circumferential magnetic blocks adopted by the radial magnet c are 12, 24 or 36 respectively.

4. The modular method of the all-permanent-magnet electron cyclotron resonance ion source according to claim 1, characterized in that, The magnetic rings providing axial magnetic fields are divided according to the axial thickness d ≤ 50 mm, and the axial thickness of the axial magnet is a multiple of d.

5. The modular method of the all-permanent-magnet electron cyclotron resonance ion source according to claim 1, characterized in that, The magnetic rings providing axial magnetic fields are divided according to the radial thickness r ≤ 50 mm, and the radial thickness of the axial magnet is a multiple of r.

6. The modular method of the all-permanent-magnet electron cyclotron resonance ion source as described in claim 1, wherein The overall inner radius of the ion source is: 50 mm ≥ R0 ≥ 20 mm.

7. The modular method of the all-permanent-magnet electron cyclotron resonance ion source according to claim 6, characterized in that, For light ions and multi-ions with low charge states, the outer diameter of the magnet is R0 + 50 mm; for ions from light ions to heavier ions and medium and higher charge state ions, the outer diameter of the magnet is selected as R0 + 50 + 50 mm; for high charge state ions of heavy ions, the outer diameter of the magnet is selected as R0 + 50 + 50 + 50 mm.

8. A modular device for an all-permanent-magnet electron cyclotron resonance ion source, characterized in that Including: A first axial magnet, a second axial magnet and a radial magnet; An ion source magnet is composed of a first axial magnet, a second axial magnet and a radial magnet, and the radial magnet is located between the first axial magnet and the second axial magnet. The first axial magnet and the second axial magnet have opposite magnetization directions. The first axial magnet and the second axial magnet are composed of combinations of magnetic rings with different radii, different axial thicknesses and capable of providing axial magnetic fields. The first axial magnet and the second axial magnet are divided into multiple groups according to the axial thickness. The number of divided groups is n times the axial thickness d, where n is an integer. The radial magnet adopts a HALBACH structure with three numbers of circumferential magnetic blocks and is divided into multiple groups according to the axial thickness. The number of divided groups is n times the axial thickness d. The radial magnet, the first axial magnet and the second axial magnet are all divided into 12n magnetic blocks along the angular direction. According to the performance requirements of the ion source, the first axial magnet, the second axial magnet and the radial magnet are arranged and combined according to n times the axial thickness d to form a complete ion source magnet.

9. The modular device of the all-permanent-magnet electron cyclotron resonance ion source according to claim 8, characterized in that, The magnetic ring providing an axial magnetic field is segmented according to an axial thickness d ≤ 50 mm, and the axial thickness of the axial magnet is a multiple of d.

10. The modular device of the all-permanent-magnet electron cyclotron resonance ion source according to claim 8, characterized in that, The magnetic ring providing an axial magnetic field is segmented according to a radial thickness r ≤ 50 mm, and the radial thickness of the axial magnet is a multiple of r.

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