Phase switch of standing wave accelerator

Abstract

The utility model relates to the field of standing wave accelerators, and provides a phase switch of a standing wave accelerator, which comprises a bridging coupling part and a conventional coupling part, the bridging coupling part and the conventional coupling part are arranged on two sides of a beam direction, and the beam is an electron beam in the standing wave accelerator; the bridging coupling part comprises at least three acceleration cavities and a bridging coupling cavity, and the bridging coupling cavity is communicated with two acceleration cavities which are not adjacent to each other; the conventional coupling part comprises acceleration cavities and conventional coupling cavities, and the number of the acceleration cavities of the conventional coupling part corresponds to that of the acceleration cavities of the bridging coupling part. The phase switch of the standing wave accelerator is used for overcoming the defects that a phase switch of an existing standing wave accelerator is not high in stability during operation and difficult to process and deploy, the energy of an output electron beam group can be flexibly changed by arranging a bridging coupling cavity and adjusting the coupling degree of the bridging coupling cavity and an accelerating cavity, and the phase switch is simple in structure and easy to implement.

Description

Technical Field

[0001] The utility model relates to the technical field of standing wave accelerators, in particular to a phase switch of a standing wave accelerator. Background Art

[0002] Standing wave accelerators are widely used in industrial inspection, medical diagnosis and treatment due to their high acceleration efficiency and compact structure. In industrial inspection, dual-energy electron beams can distinguish different materials in the object being inspected. In medical diagnosis and treatment, various treatment methods targeting adaptive radiotherapy (ART) are constantly developing, among which image-guided radiotherapy (IGRT) requires the kV electron beam for diagnosis and the MV electron beam for treatment to be integrated in the same device. Therefore, the realization of multi-energy and kV-MV electron beams has raised a major issue and direction for the development of accelerators.

[0003] The above-mentioned linear accelerator can generally be regarded as consisting of a capture section and an energy boost section. The capture section mainly realizes the capture of the electron beam generated by the electron gun and accelerates it to near the speed of light so as to effectively obtain energy gain in the energy boost section. At the same time, the capture efficiency is sensitive to changes in the input RF power. Due to the large energy adjustment range of multi-energy and kV-MV electron beams, if only the input power is adjusted, it will cause a huge change in the capture efficiency of the capture section, which is not conducive to the stable operation of the linear accelerator. Therefore, if the energy gain of the energy boost section can be adjusted independently, the output energy of the linear accelerator can be greatly changed without changing the capture efficiency. This adjustment device is also called an energy switch.

[0004] However, the phase switch of the existing standing wave accelerator has low stability during operation and is difficult to process and adjust. Utility Model Content

[0005] The utility model provides a phase switch of a standing wave accelerator, which is used to solve the defects of low stability during operation and difficult processing and adjustment of the phase switch of the existing standing wave accelerator. By setting a cross-coupling cavity and adjusting the coupling degree between the cross-coupling cavity and the accelerating cavity, the energy of the output electron bunch can be flexibly changed, and the structure is simple and easy to implement.

[0006] The utility model provides a phase switch of a standing wave accelerator, comprising a jumper coupling part and a conventional coupling part, wherein the jumper coupling part and the conventional coupling part are arranged on both sides of a beam direction, and the beam is an electron beam in the standing wave accelerator;

[0007] The cross-coupling part includes at least three accelerating chambers and one cross-coupling chamber, and the cross-coupling chamber is connected with two non-adjacent accelerating chambers;

[0008] The conventional coupling part comprises an accelerating cavity and a conventional coupling cavity, and the number of the accelerating cavities of the conventional coupling part corresponds to the number of the accelerating cavities of the cross-coupling part.

[0009] According to the phase switch of the standing wave accelerator provided by the utility model, the accelerating cavity of the cross-coupling part includes a first accelerating cavity, a second accelerating cavity and a third accelerating cavity, and the cross-coupling cavity is connected with the first accelerating cavity and the third accelerating cavity.

[0010] According to the phase switch of the standing wave accelerator provided by the utility model, the cross-coupling cavity crosses the multiple accelerating cavities of the cross-coupling part.

[0011] According to the phase switch of the standing wave accelerator provided by the utility model, the cross-coupling cavity is provided with a cross-coupling detuning mechanism, and the conventional coupling cavity is provided with a conventional detuning mechanism.

[0012] According to the phase switch of the standing wave accelerator provided by the utility model, when the phase switch is working, the conventional detuning mechanism is inserted into the conventional coupling cavity, and the cross-connection detuning mechanism is withdrawn from the cross-connection coupling cavity;

[0013] When the phase switch is not working, the conventional detuning mechanism withdraws from the conventional coupling cavity, and the cross-connection detuning mechanism is inserted into the cross-connection coupling cavity.

[0014] According to the phase switch of the standing wave accelerator provided by the utility model, when the phase switch is working, the cross-coupled cavity and the connected accelerating cavity form a double-period π / 2 mode, and the field phases in the two accelerating cavities connected by the cross-coupled cavity are opposite;

[0015] When the phase switch is not working, the conventional coupling cavity and the accelerating cavity of the conventional coupling part form a double-period π / 2 mode, and the field phases in the two accelerating cavities connected by the cross-coupling part are the same.

[0016] According to the phase switch of the standing wave accelerator provided by the utility model, when the phase switch is working, the field phases of the first accelerating cavity and the third accelerating cavity are opposite;

[0017] When the phase switch is not working, the field phases of the first accelerating cavity and the third accelerating cavity are the same, and the field phase of the second accelerating cavity is opposite.

[0018] According to the phase switch of the standing wave accelerator provided by the utility model, when the phase switch is working, there is no electric field in the second accelerating cavity.

[0019] According to the phase switch of the standing wave accelerator provided by the utility model, the beam includes transverse magnetic waves and transverse electromagnetic waves.

[0020] According to the phase switch of the standing wave accelerator provided by the utility model, the conventional coupling cavity and the cross-coupling cavity are detuned respectively, so that the field phase in the accelerating cavity is reversed.

[0021] The phase switch of the standing wave accelerator provided by the present application adopts the solution of bridging the side-coupled cavity. Under normal working conditions, it is completely consistent with the general side-coupled accelerating tube, and there is no need to consider adjusting the working parameters of input power and coupling degree; when the phase switch is activated, the phase of the subsequent cavity chain is reversed. At the same time, the two accelerating cavities bridged and the accelerating cavity between them cannot be effectively coupled, so there is actually no field in the cavity. When the beam passes through, although the field will be excited in this cavity, it is different from the working mode and frequency of the front and rear cavity chains, and will not produce effective coupling, nor will it affect the stable operation of the accelerator. In addition, the structure of the cross-connected side-coupled cavity is simple, and there is almost no difference in the processing and deployment of the traditional side-coupled cavity, and it is easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 This is one of the structural schematic diagrams of the phase switch provided by the embodiment of the utility model;

[0024] Figure 2 This is the second structural schematic diagram of the phase switch provided by the embodiment of the utility model;

[0025] Figure 3 It is one of the schematic diagrams of electric field distribution provided by the embodiment of the utility model;

[0026] Figure 4 This is the second schematic diagram of the electric field distribution provided by the embodiment of the utility model.

[0027] in:

[0028] 101-first accelerating chamber; 102-second accelerating chamber; 103-third accelerating chamber;

[0029] 104-cross-coupling cavity; 105-first conventional coupling cavity; 106-second conventional coupling cavity;

[0030] 107-a first conventional detuning mechanism; 108-a second conventional detuning mechanism;

[0031] 109-Bridge detuning mechanism. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described clearly and completely in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] The phase switch is composed of a set of conventional side-coupled cavity chains and a side-coupled cavity (hereinafter referred to as the cross-side coupled cavity) that is connected across two adjacent odd or even accelerating cavities. When the conventional side-coupled cavity is detuned, the cross-side coupled cavity and the adjacent accelerating cavity form a double-periodic π / 2 mode, and the field phases in the two accelerating cavities are opposite. When the cross-side coupled cavity is detuned, the conventional side-coupled cavity and the accelerating cavity form a double-periodic π / 2 mode, and the field phases in the two adjacent accelerating cavities of the cross-side coupled cavity are the same. In this way, when the conventional side-coupled cavity and the cross-side coupled cavity are detuned respectively, the field phase of the downstream cavity chain of the cross-side coupled cavity can be reversed, thereby changing the energy of the electron bunch finally output.

[0034] There are some patents related to phase switches in the prior art, but the energy switches based on side-coupled cavities currently all adopt the scheme of adjusting the side-coupled cavity on the adjacent accelerating cavity. Most of the phase switches use the scheme of a single side-coupled cavity. By changing the frequency of the side-coupled cavity, the amplitude and phase of the field in the rear cavity chain can be changed, but the field inversion cannot be achieved, so the energy tuning range is limited. In addition, there are some phase switches in the prior art that use a three-cavity system and a separate single-coupled cavity. When the three-cavity system is detuned, the phase shift between adjacent accelerating cavities is π, which is a normal working mode. When the single-coupled cavity is detuned, the RF power is transmitted to the adjacent accelerating cavity through the three-cavity system, and the phase change between adjacent accelerating cavities is 0, which is an energy switch mode. The three-cavity system has the opposite effect to the single-cavity system. At this time, the single cavity plays the role of an energy switch. Regardless of the working mode, the three-cavity system will work in the π / 2 mode, so there must be a field in the side-pass accelerating cavity. Since the cavity has a low no-load quality factor and large loss, it will affect the working parameters of the accelerator on the one hand and the stability of the accelerator on the other. In addition, there are three side-coupled cavities in the three-cavity system, which are not only coupled with each other but also coupled with the main cavity chain, making processing and adjustment very difficult.

[0035] Based on this, the solution of the present application provides a phase switch of a standing wave accelerator, and the specific solution is as follows.

[0036] Figure 1 This is one of the structural schematic diagrams of the phase switch provided in the embodiment of the utility model.

[0037] Figure 2 This is the second structural schematic diagram of the phase switch provided in the embodiment of the utility model.

[0038] like Figure 1 and Figure 2 As shown, this embodiment provides a phase switch of a standing wave accelerator, comprising a jumper coupling portion and a conventional coupling portion, wherein the jumper coupling portion and the conventional coupling portion are arranged on both sides of a beam direction, and the beam is an electron beam in the standing wave accelerator;

[0039] The cross-coupling part includes at least three accelerating chambers and one cross-coupling chamber 104, and the cross-coupling chamber 104 is connected with two non-adjacent accelerating chambers;

[0040] The conventional coupling part comprises an accelerating cavity and a conventional coupling cavity, and the number of the accelerating cavities of the conventional coupling part corresponds to the number of the accelerating cavities of the cross-coupling part.

[0041] In practical applications, the cross-coupling cavity 104 can be connected across two adjacent odd-numbered or even-numbered accelerating cavities.

[0042] In implementation, such as Figure 1 and Figure 2 As shown, the number of conventional coupling cavities may be two, and each conventional coupling cavity in the chain is respectively a first conventional coupling cavity 105 and a second conventional coupling cavity 106 .

[0043] The phase switch of the standing wave accelerator provided in this embodiment adopts the solution of bridging the side-coupled cavity. Under normal working conditions, it is completely consistent with the general side-coupled accelerating tube, and there is no need to consider adjusting the working parameters of input power and coupling degree; when the phase switch is activated, the phase of the subsequent cavity chain is reversed. At the same time, the two accelerating cavities that are bridged and the accelerating cavity between them cannot be effectively coupled, so there is actually no field in the cavity. When the beam passes through, although the field will be excited in this cavity, it is different from the working mode and frequency of the front and rear cavity chains, and will not produce effective coupling, nor will it affect the stable operation of the accelerator. In addition, the structure of the cross-connected side-coupled cavity is simple, and there is almost no difference in processing and deployment from the traditional side-coupled cavity, and it is easy to implement.

[0044] In an exemplary embodiment, the accelerating chamber of the cross-coupling portion includes a first accelerating chamber 101 , a second accelerating chamber 102 , and a third accelerating chamber 103 , and the cross-coupling chamber 104 is in communication with the first accelerating chamber 101 and the third accelerating chamber 103 .

[0045] In an exemplary embodiment, the cross-coupling cavity 104 crosses multiple accelerating cavities of the cross-coupling portion.

[0046] In an exemplary embodiment, the cross-coupling cavity 104 is provided with a cross-coupling detuning mechanism 109 , and the conventional coupling cavity is provided with a conventional detuning mechanism.

[0047] In actual applications, a through hole that cooperates with the cross-detuning mechanism 109 is provided in the cross-coupling cavity 104. When the cross-detuning mechanism 109 is inserted into the through hole of the cross-coupling cavity 104, the cross-coupling cavity 104 is detuned; a through hole that cooperates with the conventional detuning mechanism is also provided in the conventional coupling cavity. When the conventional detuning mechanism is inserted into the through hole of the conventional coupling cavity, the conventional coupling cavity is detuned.

[0048] In implementation, when the number of conventional coupling cavities is two, the conventional detuning mechanism corresponding to the first conventional coupling cavity 105 is the first conventional detuning mechanism 107 , and the conventional detuning mechanism corresponding to the second conventional coupling cavity 106 is the first second conventional detuning mechanism 108 .

[0049] In an exemplary embodiment, when the phase switch is operating, the conventional detuning mechanism is inserted into the conventional coupling cavity, and the cross-connection detuning mechanism 109 is withdrawn from the cross-connection coupling cavity 104;

[0050] When the phase switch is not working, the conventional detuning mechanism withdraws from the conventional coupling cavity, and the cross-connection detuning mechanism 109 is inserted into the cross-connection coupling cavity 104 .

[0051] In an exemplary embodiment, when the phase switch is in operation, the cross-coupling cavity 104 forms a double-periodic π / 2 mode with the connected accelerating cavity, and the field phases in the two accelerating cavities connected by the cross-coupling cavity 104 are opposite;

[0052] When the phase switch is not working, the conventional coupling cavity and the accelerating cavity of the conventional coupling part form a double-period π / 2 mode, and the field phases in the two accelerating cavities connected by the cross-coupling part are the same.

[0053] In an exemplary embodiment, when the phase switch is operating, the field phases of the first accelerating cavity 101 and the third accelerating cavity 103 are opposite;

[0054] When the phase switch is not working, the field phases of the first accelerating cavity 101 and the third accelerating cavity 103 are the same, and the field phase of the second accelerating cavity 102 is opposite.

[0055] In an exemplary embodiment, when the phase switch is operating, there is no electric field in the second accelerating cavity 102 .

[0056] In practical applications, the present application also provides a schematic diagram of the electric field distribution when the phase switch is working and not working, where Figure 3 A schematic diagram of the electric field distribution when the phase switch provided in the embodiment of the present application is working, Figure 4 A schematic diagram of the electric field distribution when the phase switch provided in the embodiment of the present application is not working, wherein Figure 3 and Figure 4 The examples are all based on the case where the number of acceleration cavities is three.

[0057] like Figure 3As shown, when the phase switch is working, the electric fields of the first accelerating cavity 101 and the third accelerating cavity 103 correspond to the electric fields of the upper and lower bands respectively, and the electric field of the second accelerating cavity 102 corresponds to the middle part without electric field. This also means that when the phase switch is working, there are electric fields in the first accelerating cavity 101 and the third accelerating cavity 103, and the field phases are opposite, and there is no electric field in the second accelerating cavity 102.

[0058] like Figure 4 As shown, when the phase switch is not working, the electric fields of the first accelerating cavity 101 and the third accelerating cavity 103 correspond to the electric fields of the two bands below the axis, and the electric field of the second accelerating cavity 102 corresponds to the electric field of the band above the axis. This also means that when the phase switch is not working, there are electric fields in the first accelerating cavity 101, the second accelerating cavity 102 and the third accelerating cavity 103, and the electric fields of the first accelerating cavity 101 and the third accelerating cavity 103 are in the same phase, which is opposite to the electric field of the second accelerating cavity 102.

[0059] In an exemplary embodiment, the beam includes a transverse magnetic wave and a transverse electromagnetic wave.

[0060] In practical applications, electromagnetic waves transmitted in a certain direction in a waveguide can be divided into TM mode and TEM mode according to the directional relationship between the electric field component and the magnetic field component and the wave vector. The TM mode refers to an electromagnetic wave with an electric field component but no magnetic field component in the propagation direction, which is called a transverse magnetic wave, also called a p-wave, and is a fast wave; the TEM mode refers to an electromagnetic wave with no electric field and magnetic field components in the propagation direction, also called a transverse electromagnetic wave.

[0061] In an exemplary embodiment, the conventional coupling cavity and the cross-coupling cavity 104 are detuned respectively so as to accelerate the reversal of the field phase in the cavity.

[0062] In practical applications, when the conventional side-coupled cavity is detuned, the cross-side coupled cavity and the adjacent accelerating cavity form a double-periodic π / 2 mode, and the field phases in the two accelerating cavities are opposite. When the cross-side coupled cavity is detuned, the conventional side-coupled cavity and the accelerating cavity form a double-periodic π / 2 mode, and the field phases in the two accelerating cavities adjacent to the cross-side coupled cavity are the same. In this way, when the conventional side-coupled cavity and the cross-side coupled cavity are detuned respectively, the field phase of the downstream cavity chain of the cross-side coupled cavity can be reversed, thereby changing the energy of the electron bunch outputted in the end.

[0063] The device embodiments described above are merely illustrative. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A phase switch of a standing wave accelerator, characterized in that: It comprises a cross-coupling part and a conventional coupling part, wherein the cross-coupling part and the conventional coupling part are arranged on both sides of a beam direction, and the beam is an electron beam in the standing wave accelerator; The cross-coupling portion includes at least three accelerating chambers and one cross-coupling chamber, and the cross-coupling chamber is connected to two non-adjacent accelerating chambers; The conventional coupling part comprises an accelerating cavity and a conventional coupling cavity, and the number of the accelerating cavities of the conventional coupling part corresponds to the number of the accelerating cavities of the cross-coupling part.

2. The phase switch of the standing wave accelerator according to claim 1, characterized in that: The acceleration chamber of the cross-coupling portion includes a first acceleration chamber, a second acceleration chamber and a third acceleration chamber, and the cross-coupling chamber is connected to the first acceleration chamber and the third acceleration chamber.

3. The phase switch of the standing wave accelerator according to claim 1, characterized in that: The cross-coupling cavity crosses over the multiple accelerating cavities of the cross-coupling portion.

4. The phase switch of the standing wave accelerator according to claim 1, characterized in that: The cross-coupling cavity is provided with a cross-coupling detuning mechanism, and the conventional coupling cavity is provided with a conventional detuning mechanism.

5. The phase switch of the standing wave accelerator according to claim 4, characterized in that: When the phase switch is working, the conventional detuning mechanism is inserted into the conventional coupling cavity, and the cross-connection detuning mechanism is withdrawn from the cross-connection coupling cavity; When the phase switch is not working, the conventional detuning mechanism exits the conventional coupling cavity, and the cross-coupling detuning mechanism is inserted into the cross-coupling cavity.

6. The phase switch of the standing wave accelerator according to claim 4, characterized in that: When the phase switch is working, the cross-coupled cavity and the connected accelerating cavity form a double-period π / 2 mode, and the field phases in the two accelerating cavities connected by the cross-coupled cavity are opposite; When the phase switch is not working, the conventional coupling cavity and the accelerating cavity of the conventional coupling part form a double-period π / 2 mode, and the field phases in the two accelerating cavities connected by the cross-coupling part are the same.

7. The phase switch of the standing wave accelerator according to claim 2, characterized in that: When the phase switch is in operation, the field phases of the first accelerating cavity and the third accelerating cavity are opposite; When the phase switch is not working, the field phases of the first accelerating cavity and the third accelerating cavity are the same, and the field phase of the second accelerating cavity is opposite.

8. The phase switch of the standing wave accelerator according to claim 7, characterized in that: When the phase switch is working, there is no electric field in the second accelerating cavity.

9. The phase switch of the standing wave accelerator according to claim 1, characterized in that: The beam includes transverse magnetic waves and transverse electromagnetic waves.

Images