Frequency adjustable acceleration device, accelerator including the same and adjustment method thereof

Abstract

The present invention provides a frequency-adjustable acceleration device, comprising: an acceleration tube, configured to establish an acceleration electromagnetic field by receiving microwaves and accelerate an electron beam entering the acceleration tube; and a tuner, coupled to the acceleration tube through a first coupling hole, configured to adjust the operating frequency of the acceleration tube. The present invention focuses on solving the frequency drift problem of the coupler in the design and production of the acceleration tube, avoiding repeated testing and repair of the coupler, reducing the tuning time, improving the yield rate of the acceleration tube, and improving the work efficiency.

Description

Technical Field

[0001] The present invention relates to microwave-related fields, and in particular to a frequency-adjustable acceleration device, an accelerator comprising the same, and an adjustment method thereof. Background Art

[0002] As an X-ray source, accelerators are widely used in medical radiotherapy, industrial non-destructive testing, radiation imaging and other fields. They are composed of electron guns, modulators, power sources, microwave transmission systems, accelerating tubes, focusing systems, vacuum systems, etc. The accelerating tube is one of the core components of the accelerator.

[0003] The basic working principle of the accelerator: the modulator generates a high-voltage pulse and a delayed pulse. The high-voltage pulse excites the power source, and the output high-power radio frequency pulse passes through the microwave transmission system and enters the accelerating tube to establish a radio frequency acceleration electromagnetic field; the other delayed pulse is provided to the electron gun to draw out the electron beam, which is injected into the accelerating tube and accelerated by the accelerating electromagnetic field, thereby generating a high-energy electron beam or an electron beam hitting a heavy metal target to produce X-rays.

[0004] The external power is fed into the accelerating tube through the coupling hole of the coupler. The coupler is a special and key cavity type in the accelerating tube, such as Figure 1 As shown in the figure, it is based on the accelerating cavity, with a coupling hole opened laterally to connect with the waveguide. The opening of the accelerating cavity will inevitably cause the frequency drift of the cavity. The stable operation of the accelerating tube requires that the resonant frequencies of the various cavity types (accelerating cavity, coupler and coupling cavity) that make up the accelerating tube need to be consistent. Ensuring the consistency of the frequencies of various cavity types is a major difficulty in the design and production of accelerating tubes, which places high demands on the accuracy of accelerating tube simulation and the reliability of processing technology.

[0005] The standard for whether the resonant frequency is consistent is to measure the field distribution curve of the accelerating tube. A qualified accelerating tube should have an electric field in the accelerating cavity and a very small electric field value in the coupling cavity, basically lower than 5% of the electric field value in the accelerating cavity.

[0006] Usually, in order to ensure that the working frequency of the coupler is at the resonant frequency, the process production parameters are generally required to reach the simulation design values ​​when processing the coupler components. This requires very high accuracy of the simulation and reliability of the processing technology. Another method is to process the key dimensions that affect the coupler frequency (such as Figure 1 A certain margin is left for the dimension D) shown, and the resonant frequency of the coupler is made consistent with the resonant frequency of the remaining cavity chains through repeated tests and adjustments.

[0007] The existing methods for ensuring the resonant frequency of the coupler have very high requirements on simulation accuracy and reliability of the processing technology. On the other hand, the method of multiple repairs will increase the time cost and processing cost and have low efficiency.

[0008] Another point worth noting is that the production process of the accelerating tube involves a process in which, after tuning is completed, the entire tube needs to be welded at high temperature (550°C) and annealed to remove stress and gas impurities. This will cause the accelerating tube to undergo a certain degree of plastic deformation, resulting in inconsistent frequencies in the various cavities of the accelerating tube. However, the accelerating tube has already been welded into a whole tube and the key dimensions cannot be adjusted.

[0009] Once the resonance fails, a certain degree of electric field will appear in the coupling cavity, which will slow down the particles.

[0010] Often at this time, in order to achieve the design goals of the accelerating tube (a certain energy and dose rate), it is only possible to sacrifice the power source power. However, looking at the domestic power source market, increasing the peak power of the power source is also a technical challenge.

[0011] The contents of the background technology section are merely the technologies known to the public and do not necessarily represent the existing technologies in the field. Summary of the invention

[0012] In view of at least one defect of the prior art, the present invention provides a frequency-adjustable acceleration device, which can solve the problem of frequency inconsistency between a coupler and an adjacent acceleration cavity caused by frequency drift of a coupler in the design and production of an accelerating tube, and aims to provide a flexible and adjustable design scheme for the design and production of an accelerating tube, thereby reducing production costs and reducing the sacrifice of power source power.

[0013] The present invention provides a frequency-adjustable acceleration device, comprising: an accelerating tube, configured to establish an accelerating electromagnetic field by receiving microwaves and accelerate an electron beam entering the accelerating tube; and a tuner, coupled to the accelerating tube through a first coupling hole, configured to adjust the operating frequency of the accelerating tube.

[0014] According to one aspect of the present invention, the accelerating tube comprises: a plurality of accelerating cavities configured to establish an accelerating electromagnetic field and accelerate the electron beam, wherein the first coupling hole is located on the cavity wall of one of the accelerating cavities; and a coupling cavity arranged between adjacent accelerating cavities, configured to couple the microwaves.

[0015] According to one aspect of the present invention, the tuner comprises: a tuner housing, wherein the tuner housing has a resonant cavity inside, and the resonant cavity is connected to one of the accelerating cavities of the accelerating tube through a first coupling hole; a tuning rod, which enters the resonant cavity through a through hole and is configured to adjust the operating frequency of the accelerating tube by adjusting the depth of the tuning rod entering the resonant cavity.

[0016] According to one aspect of the present invention, the tuner and one of the acceleration cavities form a radial cavity chain. When the depth of the tuning rod entering the resonant cavity increases, the frequency of the radial cavity chain decreases; when the depth of the tuning rod entering the resonant cavity decreases, the frequency of the radial cavity chain increases.

[0017] According to one aspect of the present invention, the resonant cavity has an I-shaped structure, a spherical structure, an ellipsoidal structure or a cylindrical structure.

[0018] According to one aspect of the present invention, the tuner housing further includes: a choke structure, disposed on a side of the through hole close to the resonant cavity, configured to prevent microwave leakage; and an airtight device, disposed on a side of the through hole away from the resonant cavity, configured to prevent air from entering the resonant cavity.

[0019] According to one aspect of the present invention, the acceleration device comprises a plurality of replaceable tuners, each tuner being sized to correspond to microwaves of different frequencies.

[0020] According to one aspect of the present invention, the acceleration device also includes a waveguide system, which includes: a waveguide window configured to receive the microwaves and isolate the air; and a waveguide coupled between the waveguide window and the acceleration tube, connected to the acceleration tube through a second coupling hole, and configured to transmit the microwaves.

[0021] According to one aspect of the present invention, the radial cavity chain further comprises the waveguide, and the waveguide and the tuner are both coupled to one of the accelerating cavities of the accelerating tube, and the frequency of the radial cavity chain is adjusted by the tuner to achieve adjustable operating frequency of the accelerating tube.

[0022] According to one aspect of the present invention, the accelerating device comprises a plurality of tuners, and the plurality of tuners are coupled to one or more accelerating cavities of the accelerating tube through a plurality of first coupling holes.

[0023] The present invention also provides an accelerator, comprising: a power source configured to emit microwaves; an electron gun configured to emit electron beams; and the above-mentioned acceleration device, wherein the acceleration device is coupled to the power source and the electron gun, configured to receive the microwaves to establish an accelerating electromagnetic field, receive the electron beam and accelerate it through the accelerating electromagnetic field, wherein the operating frequency of the acceleration device is adjustable.

[0024] According to one aspect of the present invention, the electron gun is coupled to the first cavity of the accelerating tube, and the accelerator also includes a target structure or a window structure coupled to the last cavity of the accelerating tube, the target structure is configured to receive the electron beam accelerated by the accelerating tube and generate X-rays, and the window structure is configured to extract the electron beam accelerated by the accelerating tube.

[0025] The present invention also provides a method for adjusting the operating frequency of the acceleration device as described above, comprising: adjusting the tuner to adjust the operating frequency.

[0026] The features and advantages described in the specification are not exhaustive, and in particular, many additional features and advantages will be apparent to those of ordinary skill in the art in conjunction with the drawings and the specification. In addition, it should be noted that the terms used in this specification are selected primarily for readability and guidance purposes, and may not be selected to describe or limit the inventive technical solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure. In the drawings:

[0028] Figure 1 A three-dimensional mechanical cross-section of an accelerating tube and a waveguide is shown;

[0029] Figure 2A An oblique view of a three-dimensional mechanical model of an accelerating device according to an embodiment of the present invention is shown;

[0030] Figure 2B Shows Figure 2A A forward cross-sectional view of a three-dimensional mechanical model;

[0031] Figure 3A A front cross-sectional view of a tuner is shown;

[0032] Figure 3B An oblique cutaway view of a tuner is shown;

[0033] Figure 3C shows a top view of the tuner;

[0034] Figure 3D A schematic diagram of a 3D model of a tuner is shown;

[0035] Figure 4 A schematic diagram showing the depth of the tuning rod of the tuner inserted into the resonant cavity and the change in the axial cavity chain frequency;

[0036] Figure 5A A simulation diagram of an acceleration device without a waveguide connected according to an embodiment of the present invention is shown;

[0037] Figure 5B A simulation diagram of an acceleration device with open coupling holes connected to waveguides according to an embodiment of the present invention is shown;

[0038] Figure 5C A simulation diagram of an acceleration device after adjusting a tuning rod according to an embodiment of the present invention is shown; and

[0039] Figure 6 A schematic diagram of an accelerator of the present invention is shown. DETAILED DESCRIPTION

[0040] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0041] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0042] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0043] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is lower in level than the second feature.

[0044] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can be aware of the application of other processes and / or the use of other materials.

[0045] The present invention designs an accelerating device with a tuner connected to an accelerating tube, and adjusts the operating frequency of the accelerating tube by adjusting the tuner. The invention focuses on solving the problem of inconsistent frequency between the coupler and the adjacent accelerating cavity caused by coupler frequency drift in the design and production of accelerating tubes, and aims to provide a flexible and adjustable design scheme for the design and production of accelerating tubes, reduce production costs and reduce the sacrifice of power source power.

[0046] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0047] The present invention provides a frequency-adjustable acceleration device 100, such as Figure 2A As shown, it includes an accelerating tube 1001 and a tuner 1002, wherein the accelerating tube 1001 establishes an accelerating electromagnetic field by receiving microwaves and accelerates the electron beam entering the accelerating tube 1001; the tuner 1002 is connected to the accelerating tube 1001 through a first coupling hole H1 (see Figure 2B ) is coupled to the accelerating tube 1001 and is configured to adjust the operating frequency of the accelerating tube 1001.

[0048] like Figure 2BAs shown, the accelerating tube 1001 includes a plurality of accelerating cavities 1001-1, a plurality of coupling cavities 1001-2 and a coupler 1001-3. The accelerating cavity 1001-1 is configured to establish an accelerating electromagnetic field and accelerate the electron beam, the coupling cavity 1001-2 is configured to couple microwaves, the coupler 1001-3 is a type of accelerating cavity, and the external power is fed into the accelerating tube 1001 through the coupler 1001-3 to generate an accelerating electromagnetic field. The first coupling hole H1 is located on the coupler 1001-3 and is a lateral opening.

[0049] Figure 3A The front cross-sectional view of a tuner 1002 according to an embodiment of the present invention is shown, and the tuner 1002 includes a tuner housing 1002-1, a resonant cavity 1002-2, and a tuning rod 1002-3. The tuner housing 1002-1 has a resonant cavity 1002-2 inside, and the resonant cavity 1002-2 is connected to the coupler 1001-3 of the accelerating tube 1001 through a first coupling hole H1; the tuning rod 1002-3 enters the resonant cavity 1002-2 through a through hole, and is configured to adjust the operating frequency of the accelerating tube 1001 by adjusting the depth of the tuning rod 1002-3 entering the resonant cavity 1002-2.

[0050] Specifically, in the axial direction of the accelerating tube 1001, each cavity type together constitutes an axial cavity chain, and adjusting the frequency of the axial cavity chain is to adjust the operating frequency of the accelerating tube 1001. The resonant cavity 1002-2 in the tuner 1002 and the coupler 1001-3 constitute a radial cavity chain. When the depth of the tuning rod 1002-3 entering the resonant cavity 1002-2 increases, the frequency of the radial cavity chain decreases; when the depth of the tuning rod 1002-3 entering the resonant cavity 1002-2 decreases, the frequency of the radial cavity chain increases. Adjusting the frequency of the radial cavity chain can indirectly adjust the frequency of the axial cavity chain, that is, adjust the operating frequency of the accelerating tube 1001.

[0051] like Figure 3A As shown, the front cross-sectional view of the resonant cavity 1002-2 of the tuner 1002 is an "I"-shaped structure. For the S band (resonant frequency 2998MHz), the dimensions of the tuner 1002 are that the resonant cavity 1002-2 has an outer diameter D1 = Φ46.58mm, an inner diameter D2 = Φ20mm, a depth L = 10mm, and a through hole D3 = Φ5mm in the middle, which matches the Φ5 metal tuning rod 1002-3. Figure 3B An oblique cross-sectional view of tuner 1002 is shown.

[0052] Figure 3C shows a top view of the tuner, Figure 3DAs shown in the figure, the resonant cavity 1002-2 of the tuner 1002 is connected to the coupler 1001-3 through the first coupling hole H1. Preferably, the first coupling hole H1 is an oblong hole with a size of L1*L2=30mm*9mm. The three-dimensional mechanical model of the first coupling hole H1 assembled with the accelerating tube 1001 is as shown in FIG. Figure 2B The first coupling hole may also adopt other shapes, and the size needs to be determined by simulation results.

[0053] According to a preferred embodiment of the present invention, the resonant cavity 1002-2 may also adopt a spherical structure, an ellipsoidal structure or a cylindrical structure.

[0054] The size of the tuner 1002 of an embodiment of the S band is described above. Correspondingly, for the C band (5712 MHz) and the X band (9300 MHz), changing the corresponding mechanical size is also applicable. According to a preferred embodiment of the present invention, the acceleration device 100 may include a plurality of replaceable tuners 1002, and the size of each tuner 1002 is set to correspond to microwaves of different frequencies. Each tuner can complete the frequency adjustment function, and different tuners 1002 can be replaced according to actual frequency requirements.

[0055] According to a preferred embodiment of the present invention, the tuner housing 1002-1 further includes a choke structure and an airtight device, which are not shown in the figure. The choke structure is arranged on the side of the through hole close to the resonant cavity 1002-2, and is configured to prevent microwave leakage; the airtight device is arranged on the side of the through hole away from the resonant cavity 1002-2, and is configured to prevent air from entering the resonant cavity 1002-2. Those skilled in the art can understand that the choke structure and the airtight device can also be in other forms, as long as they can prevent microwave leakage and prevent air from entering, they are all within the protection scope of the present invention.

[0056] According to a preferred embodiment of the present invention, Figure 2A As shown, the acceleration device 100 further includes a waveguide system 1003, such as Figure 2B As shown, the waveguide system 1003 includes a waveguide window 1003-1 and a waveguide 1003-2. The waveguide window 1003-1 is configured to receive microwaves and isolate air; the waveguide 1003-2 is coupled between the waveguide window 1003-1 and the accelerating tube 1001, and is connected to the coupler 1001-3 of the accelerating tube 1001 through the second coupling hole H2, and is configured to transmit microwaves. Opening a hole in the coupler will inevitably cause the frequency drift of the cavity, which is also a problem to be solved in an embodiment of the present invention.

[0057] When the accelerating tube 1001 is connected to the waveguide 1003-2, the radial cavity chain includes the resonant cavity 1002-2, the coupler 1001-3 and the waveguide 1003-2, and the resonant cavity 1002-2 and the waveguide 1003-2 are coupled to the coupler 1001-3. By adjusting the depth of the tuning rod 1002-3 entering the resonant cavity 1002-2, the frequency of the radial cavity chain can be adjusted, that is, the frequency of the axial cavity chain can be indirectly adjusted, thereby achieving the adjustment of the operating frequency of the accelerating tube 1001. The solution of this embodiment can solve the frequency drift problem caused by the opening of the coupler, avoid repeated testing and repair of the coupler, reduce the tuning time, and improve the yield rate of the accelerating tube.

[0058] According to a preferred embodiment of the present invention, in order to increase the range of adjusting frequency, the acceleration device 100 may further include a plurality of tuners 1002, and the plurality of tuners 1002 are coupled to the coupler 1001-3 of the accelerating tube 1001 through a plurality of first coupling holes H1. Furthermore, if it is necessary to adjust the frequency of other accelerating cavities 1001-1, the plurality of tuners 1002 may also be coupled to one or more accelerating cavities 1001-1.

[0059] The above describes the structure of the acceleration device 100. The following uses simulation results to verify the rationality and feasibility of the acceleration device 100.

[0060] Through simulation experiments, it is found that the influence of the insertion depth of the tuning rod 1002-3 on the axial cavity chain frequency of the accelerating tube 1001 is as follows: Figure 4 As shown in the figure, there are 5 marked points, corresponding to a set of values ​​with the horizontal axis being length and the vertical axis being frequency, showing the relationship between depth and frequency. It can be seen that the tolerance of frequency adjustment is objective, and a change of about 5 wires will cause a frequency change of 12MHz.

[0061] In actual use, tuning rods 1002 - 3 of different lengths can be processed to match the length required for tuning.

[0062] An embodiment of the present invention is based on simulation verification. A simulation experiment is performed based on the acceleration device 100 of FIG. 2. The simulation results are as follows: Figure 5A , 5B and the field distribution diagram and air cavity model diagram shown in 5C.

[0063] Figure 5AThis is a simulation diagram of the accelerating device 100 when the accelerating tube 1001 does not have the second coupling hole H2 connected to the waveguide 1003-2. The accelerating device 100 includes the accelerating tube 1001 and the tuner 1002. The right figure is an air cavity model diagram; the left figure is a field distribution diagram, and the height of the curve represents the strength of the electric field. It can be seen that when each cavity is in resonance, the field of the coupling cavity 1001-2 is much smaller than the field in the accelerating cavity 1001-1, which is exactly what is needed for the actual operation of the accelerating tube 1001, that is, the smaller the electric field of the coupling cavity 1001-2 is or tends to be non-existent, the stronger the energy applied to the electron beam by the accelerating cavity 1001-1.

[0064] Figure 5B is Figure 5A After a hole is opened at the second coupling hole H2 of the coupler 1001-3 to connect the waveguide 1003-2, its air cavity model is shown in the right figure, and the acceleration device 100 includes an accelerating tube 1001, a tuner 1002 and a waveguide 1003-2. At this time, the coupler 1001-3 produces frequency drift, and the axial cavity chain frequency is inconsistent, as shown in the electric field distribution diagram on the left, and the electric field in the coupling cavity 1001-2 becomes stronger (see the waveform in the dotted circle), and accordingly, the energy obtained by the electron beam becomes smaller.

[0065] Figure 5C is Figure 5B Based on the above, a tuning rod 1002-3 is added. Its air cavity model is shown in the right figure. When the resonant cavity 1002-2 is enlarged, it can be seen that there is a bulge on the left side of the "I"-shaped waist, which is used to simulate the change in the volume of the air cavity caused by the insertion of the tuning rod 1002-3 into the resonant cavity 1002-2. Through simulation, it can be seen that adding an air cylinder with a length of 1mm and a diameter of 5mm (this value is for the S band) can reduce the electric field in the coupling cavity 1001-2 and accelerate the electric field recovery in the cavity 1001-1 to 5A. Figure 1 This indicates that in tuner 1002, the frequency drift of coupler 1001-3 can be compensated by changing the depth of the tuning rod 1002-3 inserted into the resonant cavity 1002-2.

[0066] It is worth mentioning that if the accelerator 100 is welded into a whole tube, the frequency drift of the coupler 1001-3 will cause Figure 5B The electric field of the coupling cavity 1001-2 becomes larger. In practice, the electric field of the coupling cavity 1001-2 cannot be adjusted down, and the only way is to sacrifice the precious power source power. When the power source power cannot meet the requirements, the accelerating tube 1001 will be classified as a defective tube. After installing the tuner designed by the present invention, even if the accelerating tube 1001 has been welded into a whole tube, it can be tuned again, so that the accelerating tube 1001 reaches the design value (a certain energy and dosage) under the condition that the original power source power remains unchanged, that is, the accelerating tube yield rate is improved.

[0067] Therefore, the accuracy and practicality of an embodiment of the present invention are verified by the above simulation results.

[0068] The present invention also provides an accelerator 10, such as Figure 6 As shown, including:

[0069] A power source 101 configured to emit microwaves;

[0070] an electron gun 102 configured to emit an electron beam; and

[0071] As described above, the acceleration device 100 is coupled to a power source 101 and an electron gun 102, and is configured to receive microwaves to establish an accelerating electromagnetic field, receive an electron beam and accelerate it through the accelerating electromagnetic field, wherein the operating frequency of the acceleration device 100 is adjustable.

[0072] According to a preferred embodiment of the present invention, the electron gun 102 is coupled to the first cavity of the accelerating tube 1001, and the accelerator 10 also includes a target structure or a window structure 103 coupled to the last cavity of the accelerating tube 1001, wherein the target structure is configured to receive the electron beam accelerated by the accelerating tube 1001 and generate X-rays, and the window structure is configured to lead out the electron beam accelerated by the accelerating tube 1001.

[0073] The present invention further provides a method for adjusting the operating frequency of the acceleration device 100 as described above, comprising: adjusting the tuner 1002 to adjust the operating frequency.

[0074] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, 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 frequency-adjustable acceleration device, comprising: An accelerating tube, configured to establish an accelerating electromagnetic field by receiving microwaves and accelerate an electron beam entering the accelerating tube; A tuner, coupled to the accelerating tube through a first coupling hole, configured to adjust the operating frequency of the accelerating tube; and A waveguide system, the waveguide system comprising: a waveguide, connected to the accelerating tube through a second coupling hole, configured to transmit the microwave, The accelerating tube comprises: A plurality of accelerating cavities, configured to establish an accelerating electromagnetic field and accelerate the electron beam, wherein the first coupling hole is located on a cavity wall of one of the accelerating cavities; and a coupling cavity arranged between adjacent accelerating cavities, configured to couple the microwaves, The tuner comprises: A tuner housing, wherein a resonant cavity is provided inside the tuner housing, and the resonant cavity is connected to one of the accelerating cavities of the accelerating tube through a first coupling hole; A tuning rod enters the resonant cavity through a through hole, and is configured to adjust the operating frequency of the accelerating tube by adjusting the depth of the tuning rod entering the resonant cavity. The tuner and one of the accelerating cavities form a radial cavity chain. When the depth of the tuning rod entering the resonant cavity increases, the frequency of the radial cavity chain decreases; when the depth of the tuning rod entering the resonant cavity decreases, the frequency of the radial cavity chain increases. The radial cavity chain also includes the waveguide. The waveguide and the tuner are both coupled to one of the accelerating cavities of the accelerating tube. The frequency of the radial cavity chain is adjusted by the tuner to achieve adjustable operating frequency of the accelerating tube. The acceleration device includes a plurality of replaceable tuners, and the size of each tuner is set to correspond to microwaves of different frequencies.

2. The acceleration device as claimed in claim 1, wherein the resonant cavity has an I-shaped structure, a spherical structure, an ellipsoidal structure or a cylindrical structure.

3. The acceleration device of claim 2, wherein the tuner housing further comprises: a choke structure, disposed on a side of the through hole close to the resonant cavity, configured to prevent microwave leakage; and The airtight device is arranged on a side of the through hole away from the resonant cavity and is configured to prevent air from entering the resonant cavity.

4. The acceleration device of claim 1, wherein the waveguide system further comprises: a waveguide window configured to receive the microwave and isolate air; The waveguide is coupled between the waveguide window and the accelerating tube.

5. The accelerating device according to any one of claims 1 to 3, wherein the accelerating device comprises a plurality of tuners, and the plurality of tuners are coupled to one or more accelerating cavities of the accelerating tube through a plurality of first coupling holes.

6. An accelerator, comprising: a power source configured to emit microwaves; an electron gun configured to emit an electron beam; and The acceleration device according to any one of claims 1 to 5, wherein the acceleration device is coupled to the power source and the electron gun, and is configured to receive the microwave to establish an accelerating electromagnetic field, receive the electron beam and accelerate it through the accelerating electromagnetic field, wherein the operating frequency of the acceleration device is adjustable.

7. The accelerator of claim 6, wherein the electron gun is coupled to a first cavity of the accelerating tube, and the accelerator further comprises a target structure or a window structure coupled to a last cavity of the accelerating tube, the target structure being configured to receive the electron beam accelerated by the accelerating tube and generate X-rays, and the window structure being configured to extract the electron beam accelerated by the accelerating tube.

8. A method for adjusting the operating frequency of an acceleration device according to any one of claims 1 to 5, comprising: The tuner is adjusted to adjust the operating frequency.

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