Plasma electromagnetic excitation circuit of multi-acceleration unit type superconducting cavity

Abstract

The utility model discloses a kind of multi-acceleration unit type superconducting cavity plasma electromagnetic excitation circuit, and circuit includes: first radio frequency signal source and second radio frequency signal source are connected to power combiner, then sequentially connect power amplifier, circulator, directional coupler and the power coupler of superconducting cavity, the isolated port of circulator connects matching load, the coupling end of directional coupler connects first power meter, the isolated end of directional coupler connects second power meter.The signal provided by first radio frequency signal source aims at establishing the highest value of electric field in some unit of multi-acceleration unit type superconducting cavity and its symmetric unit, and the signal provided by second radio frequency signal source makes some unit and its symmetric unit produce 10% electric field amplitude difference, so that only one unit is at the highest value of electric field.The utility model can make each acceleration unit of multi-acceleration unit type superconducting cavity sequentially at the highest value of electric field excitation plasma, so that plasma effectively washes each acceleration unit.

Description

Technical Field

[0001] This invention belongs to the technical field of superconducting cavity plasma cleaning, specifically relating to a multi-acceleration unit type superconducting cavity plasma electromagnetic excitation circuit. Background Technology

[0002] Superconducting accelerators, due to their high efficiency and low power consumption, have become the preferred type of large-scale scientific accelerator facilities under construction internationally. However, long-term operational data of superconducting accelerators indicate that field emission is the main factor leading to the online performance degradation of superconducting cavities, and the most effective cutting-edge technology for eliminating field emission online is online plasma cleaning of superconducting cavities.

[0003] The basic working principle of online plasma cleaning of superconducting cavities is that a specific ratio of inert gas and oxygen dissociates into plasma in the electromagnetic field environment inside the superconducting cavity. The plasma then undergoes a chemical and physical reaction with contaminants or defects on the walls of the superconducting cavity, thereby effectively eliminating the field emission effect.

[0004] Multi-accelerator unit superconducting cavities are a common cavity type in the high-energy acceleration section of superconducting accelerators. Due to the geometric symmetry of their structure, multi-accelerator unit superconducting cavities utilize conventional TM... 010 When a single mode in the passband excites an electromagnetic field, the electric field amplitudes of multiple acceleration units are theoretically the same. However, in practice, due to the manufacturing error of the cavity, the electric field amplitude in a certain acceleration unit will inevitably be relatively higher, but this cannot be known. This characteristic makes it difficult to determine which acceleration unit the plasma was ignited in during online plasma cleaning of the superconducting cavity. This also means that it is impossible to guarantee that each acceleration unit can be cleaned by plasma.

[0005] In summary, the electromagnetic field distribution characteristics of multi-accelerator unit superconducting cavities largely limit the effectiveness that plasma cleaning can achieve. Therefore, an unconventional electromagnetic field excitation method is needed for multi-accelerator unit superconducting cavities to avoid symmetrical distribution of the electromagnetic field within the cavity, so that each acceleration unit is sequentially at the highest electric field value to ignite the plasma, thereby ensuring that the plasma effectively cleans each acceleration unit. Utility Model Content

[0006] The main purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a circuit and implementation method for plasma cleaning of a multi-acceleration unit type superconducting cavity. Through this invention, plasma can be sequentially excited in each acceleration unit of the multi-acceleration unit type superconducting cavity and effectively cleaned.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a multi-acceleration unit type superconducting cavity plasma electromagnetic excitation circuit, comprising:

[0009] A first radio frequency signal source and a second radio frequency signal source, wherein the output terminals of the first radio frequency signal source and the second radio frequency signal source are connected to the input terminal of the power combiner;

[0010] A power amplifier, the input of which is connected to the output of the power combiner;

[0011] The circulator has a first port connected to the output of the power amplifier, a second port connected to the input of the directional coupler, and an isolation port connected to the matched load.

[0012] A superconducting cavity power coupler, the input of which is connected to the output of the directional coupler;

[0013] The coupling end of the directional coupler is connected to a first power meter for measuring the incident power coupling value; the isolation end of the directional coupler is connected to a second power meter for measuring the reflected power coupling value.

[0014] The first radio frequency signal source is used to output a frequency signal of a preset mode in the primary mode passband of the multi-acceleration unit type superconducting cavity to establish an equal-amplitude electric field in the target acceleration unit and its symmetrical unit; the second radio frequency signal source is used to output a tuned frequency signal to generate an electric field amplitude difference of more than 10% between the target acceleration unit and its symmetrical unit, so that the target acceleration unit is at the highest electric field value.

[0015] As a preferred technical solution, the preset mode is the 5π / 6 mode, 2π / 6 mode or π / 6 mode in the primary mode passband, which corresponds to the equal amplitude electric field of the 1st, 2nd, 5th or 3rd / 4th symmetrical acceleration unit pairs in the superconducting cavity.

[0016] As a preferred technical solution, the tuning frequency signal output by the second radio frequency signal source is: a 647.94MHz or 648.06MHz signal generated by offsetting the π-mode center frequency by ±0.06MHz, with the π-mode center frequency being 648MHz; or a 645.75MHz or 645.87MHz signal generated by offsetting the 4π / 6-mode center frequency by ±0.06MHz, with the 4π / 6-mode center frequency being 645.81MHz.

[0017] As a preferred technical solution, the multi-acceleration unit type superconducting cavity includes, but is not limited to, a 6-acceleration unit type superconducting cavity.

[0018] Compared with the prior art, this utility model has the following advantages and beneficial effects:

[0019] This invention configures a mixture of inert gas and oxygen within a superconducting cavity to a preset pressure. The incident power required for plasma excitation is calibrated using the π-mode center frequency signal output from a radio frequency signal source. Based on the relationship between peak electric field strength and incident power, the incident power required to excite plasma in each acceleration unit under different operating modes (5π / 6, 2π / 6, π / 6) is calculated. Through the coordinated control of dual radio frequency signal sources, a specific frequency combination signal is injected into the multi-acceleration unit superconducting cavity. A step increase in reflected power is used as a criterion to sequentially trigger independent plasma excitation and cleaning of the 1st to 6th acceleration units. Each acceleration unit is kept cleaned with plasma for 10 minutes to ensure efficient removal of contaminants from the cavity surface. This invention uses a dual-mode superposition method and artificially adjusts the frequency detuning of the second mode to generate field asymmetry, ensuring that each acceleration unit is sequentially excited with the highest electric field value, thus demonstrating that the plasma effectively cleans each acceleration unit. By superimposing two modes and artificially tuning the second mode to break the symmetrical distribution of the electric field, this method successfully solves the problem that the superconducting cavity of the multi-acceleration unit theoretically has a symmetrical distribution of the electric field, but the electric field distribution of the symmetrical unit is different due to the processing error, so the plasma is only excited in one of the symmetrical units. This method eliminates the plasma cleaning blind zone and significantly improves the cleaning quality. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a structural diagram of a superconducting cavity plasma electromagnetic excitation circuit based on a 6-acceleration unit type according to an embodiment of the present invention;

[0022] Figure 2 This is a diagram showing the electric field intensity distribution of six modes in the fundamental mode passband of the superconducting cavity of the acceleration unit type in Embodiment 6 of this utility model (the negative sign only represents the different phases);

[0023] Figure 3 The electric field distribution diagrams for the π mode of the superconducting cavity of the acceleration unit type in Embodiment 6 of this utility model are obtained by negative tuning (0.06MHz) and positive tuning (0.06MHz) at its central resonant frequency.

[0024] Figure 4 The electric field distribution diagram is shown for the 5π / 6 mode of this utility model with the π mode center resonant frequency negatively tuned to 0.06MHz (647.94MHz) and the π mode center resonant frequency positively tuned to 0.06MHz (648.06MHz) superimposed on it.

[0025] Figure 5 The electric field distribution diagram is shown for the superimposed π-mode center resonant frequency of 0.06MHz (647.94MHz) and the π-mode center resonant frequency of 0.06MHz (648.06MHz) in the π / 6 mode of this utility model embodiment.

[0026] Figure 6 The electric field distribution diagrams for the 4π / 6 mode of the accelerating unit type superconducting cavity in Embodiment 6 of this utility model, after negative tuning of 0.06MHz and positive tuning of 0.06MHz at its center resonant frequency, are shown.

[0027] Figure 7 The electric field distribution diagrams are shown for the negative tuning of the 4π / 6 mode center resonant frequency to 0.06MHz (645.75MHz) and the positive tuning of the 4π / 6 mode center resonant frequency to 0.06MHz (645.87MHz) superimposed on the π / 6 mode of this utility model embodiment. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative effort are within the scope of protection of the present application.

[0029] In this application, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this application can be combined with other embodiments.

[0030] like Figure 1 As shown, this embodiment provides a multi-acceleration unit type superconducting cavity plasma electromagnetic excitation circuit, including a first radio frequency signal source ( Figure 1 Radio frequency signal source 1), second radio frequency signal source ( Figure 1 The components include: radio frequency signal source 2), power combiner, power amplifier, circulator, directional coupler, and first power meter. Figure 1 Power meter 1), second power meter ( Figure 1The system includes a power meter 2) and a power coupler for the superconducting cavity; the first and second radio frequency signal sources are connected to the power combiner, and then connected in sequence to the power amplifier, circulator, directional coupler and the power coupler for the superconducting cavity. The coupling end of the directional coupler is connected to the first power meter, and the isolation end is connected to the second power meter. All instruments are connected by a 50-ohm coaxial radio frequency transmission line.

[0031] More specifically, the output terminals of the first and second radio frequency signal sources are respectively connected to the input terminals of the power combiner; the input terminal of the power amplifier is connected to the output terminal of the power combiner; the first port of the circulator is connected to the output terminal of the power amplifier, the second port is connected to the input terminal of the directional coupler, and the isolation port is connected to a 50-ohm matching load; the input terminal of the superconducting cavity power coupler is connected to the output terminal of the directional coupler; the coupling terminal of the directional coupler is connected to a first power meter for measuring the incident power coupling value; the isolation terminal of the directional coupler is connected to a second power meter for measuring the reflected power coupling value; the first radio frequency signal source is used to output a frequency signal of a preset mode in the fundamental mode passband of the multi-acceleration unit type superconducting cavity to establish an equal-amplitude electric field in the target acceleration unit and its symmetrical unit; the second radio frequency signal source is used to output a tuning frequency signal to generate an electric field amplitude difference of more than 10% between the target acceleration unit and its symmetrical unit, so that the single acceleration unit is at the highest electric field value.

[0032] The following example, a 648MHz 6-acceleration-unit superconducting cavity, will be used to illustrate the theoretical basis and implementation method of this invention. It is worth noting that the aforementioned 6-acceleration-unit superconducting cavity does not constitute a limitation on the superconducting cavity of this patent; other types, such as 9-acceleration-unit superconducting cavities, are also applicable to the technical solutions of this patent.

[0033] The preset mode is the 5π / 6 mode, 2π / 6 mode or π / 6 mode in the primary mode passband, which corresponds to the equal amplitude electric field of the 1st, 2nd, 5th or 3rd / 4th symmetric acceleration unit pairs in the superconducting cavity.

[0034] The electric field distributions of the six modes in the fundamental mode passband of the six-acceleration unit superconducting cavity within the six acceleration units are as follows: Figure 1 As shown in parts (a) to (f), Figure 1 In the diagram, the horizontal axis represents the acceleration unit number, and the vertical axis represents the electric field amplitude (the negative sign only indicates a different phase). Figure 1 Parts (a) through (f) are respectively the 1π / 6 mode, 2π / 6 mode, 3π / 6 mode, 4π / 6 mode, 5π / 6 mode and π mode.

[0035] By analyzing these 6 modes, the following information can be obtained: the 5π / 6 mode can establish the highest electric field value in the 1st acceleration unit and its symmetric unit, i.e., the 6th acceleration unit; the 2π / 6 mode can establish the highest electric field value in the 2nd acceleration unit and its symmetric unit, i.e., the 5th acceleration unit; and the π / 6 mode can establish the highest electric field value in the 3rd acceleration unit and its symmetric unit, i.e., the 4th acceleration unit.

[0036] Based on the three modes mentioned above—5π / 6, 2π / 6, and π / 6—an additional field distribution is superimposed to artificially create an electric field amplitude difference of more than 10% between each accelerating unit and its symmetrical unit. This allows each accelerating unit to sequentially reach its highest electric field value to excite the plasma, thus demonstrating that the plasma effectively cleans each accelerating unit. Negative tuning of the π mode from its central resonant frequency of 648MHz to 647.94MHz can produce... Figure 3 The electric field distribution shown in section (a) is such that, by positively tuning the π mode from its central resonant frequency of 648 MHz by 0.06 MHz to 648.06 MHz, the following can be produced: Figure 3 The electric field distribution is shown in (b).

[0037] Therefore, a field distribution of 647.94 MHz is superimposed on the 5π / 6 mode, such as Figure 4 As shown in section (a), the first unit can be placed at the highest electric field value, thus only this unit can excite the plasma; while a field distribution of 648.06 MHz is superimposed on the 5π / 6 mode, as shown in section (a). Figure 4 As shown in section (b), the sixth unit can be brought to the highest electric field value, so that only this unit can generate plasma.

[0038] A field distribution of 647.94 MHz was superimposed on the 2π / 6 mode, such as Figure 5 As shown in section (a), the second unit can be brought to the highest electric field value, thus only this unit can excite the plasma; and a field distribution of 648.06 MHz is superimposed on the 2π / 6 mode, as shown in section (a). Figure 5 As shown in section (b), the fifth unit can be brought to the highest electric field value, so that only this unit can generate plasma.

[0039] By negatively tuning the 4π / 6 mode from its center resonant frequency of 645.81MHz by 0.06MHz to 645.75MHz, the following can be produced: Figure 6 The electric field distribution shown in (a) is such that, by positively tuning the 4π / 6 mode from its central resonant frequency of 645.81MHz to 645.87MHz by 0.06MHz, the following can be produced: Figure 6 The electric field distribution is shown in section (b).

[0040] Therefore, a field distribution of 645.75 MHz is superimposed on the π / 6 mode, such as Figure 7 As shown in section (a), the third unit can be brought to the highest electric field value, thus only this unit can excite the plasma; and a field distribution of 645.87 MHz is superimposed on the π / 6 mode, as shown in section (a). Figure 7 As shown in section (b), the fourth unit can be brought to the highest electric field value, so that only this unit can generate plasma.

[0041] In practical use, the first radio frequency signal source is responsible for outputting a frequency signal of one of the 5π / 6, 2π / 6 and π / 6 modes to establish almost equal maximum electric field values ​​in a certain unit and its symmetrical unit of the 6-acceleration unit superconducting cavity, and gradually increasing the signal output of the first radio frequency signal source so that the maximum electric field value in the cavity is close to the electric field value required for plasma excitation; the second radio frequency signal source is responsible for outputting a superimposed field so that a certain unit and its symmetrical unit generate an electric field amplitude difference of more than 10% and finally excite the plasma.

[0042] Another embodiment of this utility model provides a method for implementing a multi-acceleration unit type superconducting cavity plasma electromagnetic excitation circuit, comprising the following steps:

[0043] (1) The gas ratio and pressure inside the superconducting cavity have met the requirements for superconducting cavity plasma cleaning;

[0044] (2) Using a 648MHz frequency signal output from a first RF signal source, the initial output power is set to -30dBm. The power output of the first RF signal source is increased in 1dBm increments. Simultaneously, the reflected power coupling value measured by the second power meter is observed. The reflected power coupling value first increases slowly in sync with the slow increase of the output power of the first RF signal source, and then experiences a significant step increase. At this point, the increase of the power output of the first RF signal source is stopped, and the incident power coupling value P measured by the first power meter is recorded. f-DC Turn off the power output of the first radio frequency signal source and change the output power setting back to -30dBm. Calculate the incident power of the superconducting cavity using formula (1), where C in formula (1) is the coupling degree of the directional coupler, which is 40dB in this example:

[0045]

[0046] (3) Calculate the peak electric field intensity E required to excite the plasma using formula (2). peak Where the coefficient F is the incident power value P of the π mode. f With peak electric field E peak The proportionality constant of the square:

[0047] P f-π =F π *E peak2 (2)

[0048] (4) Using the peak electric field intensity E calculated in step (3) peak The incident power required to excite the plasma in the 5π / 6 mode, 2π / 6 mode, and π / 6 mode is calculated using formulas (3), (4), and (5), respectively. The F in the formulas... 5π / 6 F 2π / 6 F π / 6 The incident power values ​​P for the 5π / 6 mode, 2π / 6 mode, and π / 6 mode are respectively. f-5π / 6 P f-2π / 6 and P f-π / 6 With peak electric field intensity E peak The proportionality constant of the square:

[0049]

[0050]

[0051]

[0052] (5) Using formulas (6), (7) and (8), and substituting them into the P calculated in step (4), f- 5 π / 6 P f-2π / 6 and P f-π / 6 Calculate P' f-5π / 6-DC ,P' f-2π / 6-DC and P' f-π / 6-DC :

[0053]

[0054]

[0055]

[0056] (6) The first radio frequency signal source outputs a signal with a 5π / 6 mode frequency of 647.39MHz. The power output of the first radio frequency signal source is slowly increased in steps of 1dBm, while the incident power coupling value measured by the first power meter is observed until it reaches P'. f-5π / 6-DC Then, stop increasing the power output of the first radio frequency signal source.

[0057] (7) The initial output power of the second radio frequency signal source is set to -30dBm, and the output frequency is 647.94MHz. The power output of the second radio frequency signal source is slowly increased in 1dBm increments. At the same time, the reflected power coupling value measured by the second power meter is observed to first increase slowly in sync with the slow increase in the power output of the second radio frequency signal source, and then increase significantly in a step. At this moment, the plasma is excited in the first acceleration unit. After maintaining plasma cleaning for about 10 minutes, the power output of the first radio frequency signal source is turned off and the output power setting is changed back to -30dBm. At the same time, the power output of the second radio frequency signal source is turned off and the output power setting is changed back to -30dBm.

[0058] (8) The first RF signal source outputs a 5π / 6 mode signal at a frequency of 647.39MHz. The power output of the first RF signal source is slowly increased in steps of 1dBm, while the incident power coupling value measured by the first power meter is observed to reach P'. f-5π / 6-DC Then, stop increasing the power output of the first radio frequency signal source.

[0059] (9) The second radio frequency signal source outputs a signal with a frequency of 648.06MHz. The power output of the second radio frequency signal source is slowly increased in steps of 1dBm. At the same time, the reflected power coupling value measured by the second power meter is observed to first increase slowly in sync with the slow increase in the power output of the second radio frequency signal source, and then increase significantly in a step. At this moment, the plasma is excited in the 6th acceleration unit. After maintaining plasma cleaning for about 10 minutes, the power output of the first radio frequency signal source is turned off and the output power setting value is changed back to -30dBm. At the same time, the power output of the second radio frequency signal source is turned off and the output power setting value is changed back to -30dBm.

[0060] (10) The first radio frequency signal source outputs a signal with a 2π / 6 mode frequency of 641.48MHz. The power output of the first radio frequency signal source is slowly increased in steps of 1dBm. At the same time, the incident power coupling value measured by the first power meter is observed to reach P'. f-2π / 6-DC Then, stop increasing the power output of the first radio frequency signal source.

[0061] (11) The second radio frequency signal source outputs a signal with a frequency of 647.94MHz. The power output of the second radio frequency signal source is slowly increased in steps of 1dBm. At the same time, the reflected power coupling value measured by the second power meter is observed to first increase slowly in sync with the slow increase in the power output of the second radio frequency signal source, and then increase significantly in a step. At this moment, the plasma is excited in the second acceleration unit. After maintaining plasma cleaning for about 10 minutes, the power output of the first radio frequency signal source is turned off and the output power setting value is changed back to -30dBm. At the same time, the power output of the second radio frequency signal source is turned off and the output power setting value is changed back to -30dBm.

[0062] (12) The first radio frequency signal source outputs a signal with a 2π / 6 mode frequency of 641.48MHz. The power output of the first radio frequency signal source is slowly increased in steps of 1dBm. At the same time, the incident power coupling value measured by the first power meter is observed to reach P'. f-2π / 6-DC Then, stop increasing the power output of the first radio frequency signal source.

[0063] (13) The second radio frequency signal source outputs a signal with a frequency of 648.06MHz. The power output of the second radio frequency signal source is slowly increased in steps of 1dBm. At the same time, the reflected power coupling value measured by the second power meter is observed to first increase slowly in sync with the slow increase in the power output of the second radio frequency signal source, and then increase significantly in a step. At this moment, the plasma is excited in the 5th acceleration unit. After maintaining plasma cleaning for about 10 minutes, the power output of the first radio frequency signal source is turned off and the output power setting value is changed back to -30dBm. At the same time, the power output of the second radio frequency signal source is turned off and the output power setting value is changed back to -30dBm.

[0064] (14) The first radio frequency signal source outputs a signal with a π / 6 mode frequency of 639.86MHz. The power output of the first radio frequency signal source is slowly increased in steps of 1dBm. At the same time, the incident power coupling value measured by the first power meter is observed to reach P'. f-π / 6-DC Then, stop increasing the power output of the first radio frequency signal source.

[0065] (15) The second radio frequency signal source outputs a signal with a frequency of 645.75MHz. The power output of the second radio frequency signal source is slowly increased in steps of 1dBm. At the same time, the reflected power coupling value measured by the second power meter is observed to first increase slowly in sync with the slow increase in the power output of the second radio frequency signal source, and then increase significantly in a step. At this moment, the plasma is excited in the third acceleration unit. After maintaining plasma cleaning for about 10 minutes, the power output of the first radio frequency signal source is turned off and the output power setting value is changed back to -30dBm. At the same time, the power output of the second radio frequency signal source is turned off and the output power setting value is changed back to -30dBm.

[0066] (16) The first radio frequency signal source outputs a signal with a π / 6 mode frequency of 639.86MHz. The power output of the first radio frequency signal source is slowly increased in steps of 1dBm. At the same time, the incident power coupling value measured by the first power meter is observed to reach P'. f-π / 6-DC Then, stop increasing the power output of the first radio frequency signal source.

[0067] (17) The second radio frequency signal source outputs a signal with a frequency of 645.87 MHz. The power output of the second radio frequency signal source is slowly increased in steps of 1 dBm. At the same time, the reflected power coupling value measured by the second power meter is observed to first increase slowly in sync with the slow increase in the power output of the second radio frequency signal source, and then increase significantly in a step. At this moment, the plasma is excited in the fourth acceleration unit. After maintaining plasma cleaning for about 10 minutes, the power output of the first radio frequency signal source is turned off and the output power setting value is changed back to -30 dBm. At the same time, the power output of the second radio frequency signal source is turned off and the output power setting value is changed back to -30 dBm. Thus, each acceleration unit of the superconducting cavity of the 6 acceleration units has completed plasma excitation and cleaning.

[0068] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above embodiments are preferred embodiments of the present utility model, but the embodiments of the present utility model are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present utility model shall be considered equivalent substitutions and shall be included within the protection scope of the present utility model.

Claims

1. A multi-acceleration-unit superconducting cavity plasma electromagnetic excitation circuit, characterized by, include: A first radio frequency signal source and a second radio frequency signal source, wherein the output terminals of the first radio frequency signal source and the second radio frequency signal source are connected to the input terminal of the power combiner; A power amplifier, the input of which is connected to the output of the power combiner; The circulator has a first port connected to the output of the power amplifier, a second port connected to the input of the directional coupler, and an isolation port connected to the matched load. A superconducting cavity power coupler, the input of which is connected to the output of the directional coupler; The coupling end of the directional coupler is connected to a first power meter for measuring the incident power coupling value; the isolation end of the directional coupler is connected to a second power meter for measuring the reflected power coupling value. The first radio frequency signal source is used to output a frequency signal of a preset mode in the fundamental mode passband of the multi-acceleration unit type superconducting cavity, so as to establish an equal amplitude electric field in the target acceleration unit and its symmetrical unit; The second radio frequency signal source is used to output a tuning frequency signal, so that the target acceleration unit and its symmetrical unit generate an electric field amplitude difference of more than 10%, so that the target acceleration unit is at the highest electric field value.

2. The multi-acceleration-unit type superconducting cavity plasma electromagnetic excitation circuit according to claim 1, characterized by, The preset mode is the 5π / 6 mode, 2π / 6 mode or π / 6 mode in the primary mode passband, which corresponds to the equal amplitude electric field of the 1st, 2nd, 5th or 3rd / 4th symmetric acceleration unit pairs in the superconducting cavity.

3. The multi-acceleration-unit type superconducting cavity plasma electromagnetic excitation circuit according to claim 1, characterized by, The tuning frequency signal output by the second radio frequency signal source is either a 647.94MHz or 648.06MHz signal generated by offsetting the center frequency of the π mode by ±0.06MHz, with the center frequency of the π mode being 648MHz, or a 645.75MHz or 645.87MHz signal generated by offsetting the center frequency of the 4π / 6 mode by ±0.06MHz, with the center frequency of the 4π / 6 mode being 645.81MHz.

4. The multi-acceleration-unit type superconducting cavity plasma electromagnetic excitation circuit according to claim 1, characterized by The multi-acceleration unit type superconducting cavity includes, but is not limited to, a 6-acceleration unit type superconducting cavity.

Images