A method for realizing a high-efficiency compact klystron based on a hybrid mode resonant cavity

Abstract

This invention discloses a method for realizing a high-efficiency compact klystron based on a hybrid-mode resonator. The method includes: using the clustered center stabilization method (CSM), employing three combinations of hybrid-mode resonators, and optimizing the klystron's performance using large-signal computer software. This method reduces the required number of resonators to five when introducing one higher harmonic cavity or six when introducing two higher harmonic cavities. The three combinations of hybrid-mode resonators include the fundamental frequency f operating in TM mode. 010 Mode, second harmonic 2f operating in TM 020 Coaxial resonant cavity of mode; fundamental frequency f operates in TM 010 Mode, third harmonic 3f operating in TM 030 Coaxial resonant cavity in TM mode; second harmonic 2f operates in TM mode. 020 Mode, third harmonic 3f operating in TM 030 A coaxial resonant cavity in a specific mode. This invention is highly advantageous for reducing the weight and length of beam-wave interaction.

Description

Technical Field

[0001] This invention relates to the field of klystron technology, and more specifically to a method for realizing a high-efficiency compact klystron based on a hybrid mode resonant cavity. Background Technology

[0002] A klystron is an electronic vacuum device that converts the energy of an electron beam into microwave energy based on the principle of velocity modulation. It belongs to microwave power amplification equipment and has wide applications in military fields and daily life. A klystron consists of an electron gun, a high-frequency interaction section, a focusing magnet, and a collecting electrode, with the high-frequency interaction section accounting for most of the volume and weight of the entire klystron.

[0003] In medical accelerators, besides improving efficiency and reducing costs, a more important development trend is miniaturization. This is because medical accelerators often require rotating radiation sources, and the power source also needs to rotate. If the klystron is too large and heavy, it cannot fit into the rotating gantry. Therefore, with the advancement of klystron technology, its size and weight are gradually decreasing. If the klystron can be made sufficiently compact and lightweight, the entire accelerator system will be more compact, while simultaneously providing higher energy microwave power to the medical accelerator, thus improving equipment performance.

[0004] To achieve high efficiency while reducing the size of the klystron, the Center-Stabilized Motion (CSM) method was proposed. CSM refers to the use of higher harmonic cavities (second or third harmonic cavities) in the moiré zone to accelerate the collection of peripheral electrons over a shorter distance, quickly achieving electron beam saturation and moiré. In multi-beam klystron designs, a second harmonic cavity is often introduced into the moiré zone, causing the electron beam to form two smaller sub-clusters within a high-frequency cycle. These sub-clusters reduce the space charge force acting on the peripheral electrons, thus allowing for better collection of peripheral electrons far from the moiré center. While CSM can achieve high efficiency with a shorter beam-wave interaction length, it requires the introduction of new higher harmonic cavities. Furthermore, efficiency gradually increases and tends to saturate with the increase in the number of resonant cavities, and the length of the high-frequency interaction zone also increases linearly with the number of cavities and tends to saturate. Therefore, in common high-frequency interaction zone designs, introducing one higher harmonic cavity requires approximately seven resonant cavities, while introducing two higher harmonic cavities requires approximately eight resonant cavities.

[0005] In view of the above, this application is hereby submitted. Summary of the Invention

[0006] The technical problem to be solved by this invention is that conventional clustered center stabilization method (CSM) uses conventional single-mode resonators, and in the design scheme of common high-frequency interaction section, the introduction of high-order harmonic cavities requires at least 7 or more resonators, and the weight and length of the beam interaction are relatively large. The purpose of this invention is to provide a method for realizing a high-efficiency compact klystron based on a hybrid-mode resonator. This invention employs a hybrid-mode resonator in the design of a CSM high-efficiency klystron. The hybrid-mode resonator can replace two resonators operating in a single mode. Three combination methods are used according to requirements: a first hybrid mode (fundamental-second harmonic hybrid mode, f-2f), a second hybrid mode (fundamental-third harmonic hybrid mode, f-3f), and a third hybrid mode (second harmonic hybrid mode-third harmonic hybrid mode, 2f-3f). This allows for the use of only 5 resonators when introducing one higher harmonic cavity, or only 6 resonators when introducing two higher harmonic cavities. This is highly beneficial for reducing the weight and length of the beam-wave interaction.

[0007] This invention is achieved through the following technical solution:

[0008] A method for realizing a high-efficiency compact klystron based on a hybrid-mode resonant cavity, the method comprising:

[0009] Based on the cluster center stabilization method (CSM), three combinations of hybrid mode resonators are used to optimize the klystron performance through large-signal computer software design. This method requires only 5 resonators when introducing one higher harmonic cavity or only 6 resonators when introducing two higher harmonic cavities.

[0010] Furthermore, the three combinations of hybrid-mode resonators include a first hybrid-mode resonator, a second hybrid-mode resonator, and a third hybrid-mode resonator, wherein:

[0011] The first hybrid mode resonant cavity refers to a cavity where the fundamental frequency f operates at TM. 010 Mode, second harmonic 2f operating in TM 020 The first type is a coaxial resonant cavity with a specific mode; the second type is a hybrid mode resonant cavity referring to a cavity where the fundamental frequency f operates in the TM mode. 010 Mode, third harmonic 3f operating in TM 030 The third type of hybrid mode resonator refers to the coaxial resonator operating at the TM mode. 020 Mode, third harmonic 3f operating in TM 030 Coaxial resonant cavity of mode.

[0012] Furthermore, by employing three combinations of hybrid-mode resonant cavities, the klystron's operating performance was optimized using large-signal computer software design, including:

[0013] Five resonant cavities are used: the first resonant cavity is used as the input cavity, the fifth resonant cavity is used as the output cavity, and the three middle resonant cavities are all cluster cavities. One of the cluster cavities operates in the first hybrid mode, and the remaining resonant cavities operate in a single mode with the fundamental frequency f. Based on the field distribution of the input cavity, cluster cavity, and output cavity, the cavity frequency, cavity position, and external quality factor of the input and output cavities are optimized in large-signal computer software to obtain the working performance of the first klystron.

[0014] Furthermore, the operating performance of the first klystron includes: L-band, peak power of 11.48 MW, gain of 47.59 dB, electron beam efficiency of 62.1%, and total high-frequency interaction length < 480 mm.

[0015] Furthermore, by employing three combinations of hybrid-mode resonant cavities, the klystron's operating performance was optimized using large-signal computer software design, including:

[0016] Six resonant cavities are used: the first resonant cavity is used as the input cavity, the sixth resonant cavity is used as the output cavity, and the four middle resonant cavities are all cluster cavities. Among them, two cluster cavities operate in the first hybrid mode and the second hybrid mode, respectively. The remaining resonant cavities operate in a single mode with the fundamental frequency f. Based on the field distribution of the input cavity, cluster cavities, and output cavity, the cavity frequency, cavity position, and external quality factor of the input and output cavities are optimized in large-signal computer software to obtain the working performance of the second klystron.

[0017] Furthermore, the operating performance of the second klystron includes: L-band, peak power of 12.26 MW, gain of 47.87 dB, electron beam efficiency of 66.34%, and total high-frequency interaction length < 600 mm.

[0018] Furthermore, by employing three combinations of hybrid-mode resonant cavities, the klystron's operating performance was optimized using large-signal computer software design, including:

[0019] Six resonant cavities are used: the first resonant cavity is used as the input cavity, the sixth resonant cavity is used as the output cavity, and the four middle resonant cavities are all cluster cavities. Among them, two cluster cavities operate in the first hybrid mode and the third hybrid mode, respectively. The remaining resonant cavities operate in a single mode with the fundamental frequency f. Based on the field distribution of the input cavity, cluster cavities, and output cavity, the cavity frequency, cavity position, and external quality factor of the input and output cavities are optimized in large-signal computer software to obtain the working performance of the third klystron.

[0020] Furthermore, the operating performance of the third klystron includes: L-band, peak power of 12.09MW, gain of 47.81dB, electron beam efficiency of 65.42%, and total high-frequency interaction length <600mm.

[0021] Furthermore, the methods for obtaining the three combination modes of the hybrid-mode resonant cavity are as follows:

[0022] Based on the standard cylindrical resonant cavity in TM nip The resonant frequency expression of the mode is used to obtain the relationship between the resonant frequencies of the fundamental wave in the three modes; the three modes include TM. 010 Pattern, TM 020 Pattern, TM 030 model;

[0023] Based on the relationship between the resonant frequencies of the three modes, the resonant cavity is optimized to obtain resonant cavities for the first hybrid mode, the second hybrid mode, and the third hybrid mode.

[0024] The relationship between the resonant frequencies of the three modes includes the second harmonic 2f operating in TM. 020 Mode and fundamental frequency f operating in TM 010 The ratio of the resonant frequencies of the modes, the third harmonic 3f operating in TM 030 Mode and fundamental frequency f operating in TM 010 The ratio of the resonant frequencies of the modes, the third harmonic 3f operating in TM 030 Mode and second harmonic 2f operating in TM 020 The ratio of the resonant frequencies of the modes.

[0025] Furthermore, the standard cylindrical resonant cavity in TM nip The expression for the resonant frequency of the mode is:

[0026]

[0027] In the formula, c is the speed of light, n, i, and p are subscripts in the corresponding modes, l is the length of the resonant cavity, a is the radius of the resonant cavity, and p ni Let be the i-th root of the n-th Bessel function.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] 1. This invention discloses a method for realizing a high-efficiency compact klystron based on a hybrid-mode resonator. This invention designs three schemes using a hybrid-mode resonator: all three schemes adopt the clustered center stabilization method (CSM) and respectively employ three combinations of hybrid-mode resonators (f-2f, f-3f, 2f-3f). The klystron performance obtained by large-signal computer software design optimization confirms the feasibility of using a hybrid-mode resonator in the design of a high-efficiency CSM klystron.

[0030] 2. The present invention provides a method for realizing a high-efficiency compact klystron based on a hybrid mode resonant cavity. Compared with conventional CSM, the first / second / third schemes of the present invention reduce the number of resonant cavities by 1 to 2 while maintaining high efficiency, and also reduce the weight while shortening the length. (1) The klystron structure operating in a hybrid mode resonant cavity has higher efficiency and peak power, as well as shorter length and lighter weight, which is very beneficial to the miniaturization design of the klystron; (2) The structure of the hybrid mode resonant cavity is simple, making the processing and assembly relatively simple; (3) The use of a hybrid mode resonant cavity reduces the total number of resonant cavities and lowers the cost of the klystron. Attached Figure Description

[0031] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0032] Figure 1 This invention TM 010 Schematic diagram;

[0033] Figure 2 This invention TM 020 Schematic diagram;

[0034] Figure 3 This invention TM 030 Schematic diagram;

[0035] Figure 4 In the first embodiment of this invention, the fundamental frequency of 1.3 GHz operates in TM. 010 Mode and second harmonic 2.6GHz operation in TM 020 Schematic diagram;

[0036] Figure 5 The curves showing the variation of current harmonics and average electron velocity with longitudinal position at different radius positions in the first scheme of the present invention (the dashed lines represent the positions of the resonant cavity, and the third dashed line is where the first hybrid mode resonant cavity is used).

[0037] Figure 6This is an electron phase trajectory diagram in the first embodiment of the present invention;

[0038] Figure 7 In the second embodiment of the present invention, the fundamental frequency of 1.3 GHz operates in TM. 010 Schematic diagram of the mode and the third harmonic 3.9GHz operating in TM030 mode;

[0039] Figure 8 The curves showing the variation of current harmonics and average electron velocity with longitudinal position at different radius positions in the second scheme of the present invention (the dashed lines represent the positions of the resonant cavity, where the third dashed line is the first hybrid mode resonant cavity and the fourth dashed line is the second hybrid mode resonant cavity).

[0040] Figure 9 This is the electron phase trajectory diagram in the second embodiment of the present invention;

[0041] Figure 10 In the third embodiment of this invention, the second harmonic 2.6GHz operates at TM. 020 Mode and third harmonic 3.9GHz operation in TM 030 model;

[0042] Figure 11 The curves showing the variation of current harmonics and average electron velocity with longitudinal position at different radius positions in the third scheme of the present invention (the dashed lines represent the positions of the resonant cavity, where the third dashed line is the first hybrid mode resonant cavity and the fourth dashed line is the third hybrid mode resonant cavity).

[0043] Figure 12 This is the electron phase trajectory diagram in the third embodiment of the present invention. Detailed Implementation

[0044] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0045] The conventional cluster center stabilization method (CSM) uses a conventional single-mode resonator. In common high-frequency interaction section designs, introducing higher-order harmonic cavities requires at least seven or more resonators, resulting in relatively large weight and length of beam-wave interaction.

[0046] Therefore, in order to further reduce the weight and length of the beam-wave interaction, this invention designs a method for realizing a high-efficiency compact klystron based on a hybrid mode resonant cavity. This invention adopts a method of using a resonant cavity operating in hybrid modes in the CSM high-efficiency klystron design method. A hybrid-mode resonator can replace two resonators operating in a single mode. Three combination methods of resonators can be used depending on requirements: the first hybrid mode (fundamental-second harmonic hybrid mode, f-2f), the second hybrid mode (fundamental-third harmonic hybrid mode, f-3f), and the third hybrid mode (second harmonic hybrid mode-third harmonic hybrid mode, 2f-3f). The first hybrid mode can operate at both the fundamental and second harmonic frequencies, the second hybrid mode can operate at both the fundamental and third harmonic frequencies, and the third hybrid mode can operate at both the second and third harmonic frequencies. This means that only five resonators are needed when introducing one higher harmonic cavity, or only six resonators are needed when introducing two higher harmonic cavities. This is highly beneficial for reducing the weight and length of the beam-wave interaction.

[0047] Specifically, this invention takes into account the standard cylindrical resonant cavity in TM nip When operating in mode, its resonant frequency f0 is expressed as:

[0048]

[0049] In the formula, c is the speed of light, n, i, and p are subscripts in the corresponding modes, l is the length of the resonant cavity, a is the radius of the resonant cavity, and p ni Let be the i-th root of the n-th Bessel function.

[0050] From this, we can initially conclude that... and The relationship between them:

[0051]

[0052] Based on this relationship, the resonant cavity is optimized to obtain the first hybrid mode resonant cavity (the fundamental frequency f operates at TM). 010 Mode, second harmonic 2f operating in TM 020 The first type is a coaxial resonator with a single mode, and the second type is a hybrid mode resonator (the fundamental frequency f operates in TM mode). 010 Mode, third harmonic 3f operating in TM 030 (a coaxial resonator of the first mode) or a third hybrid mode resonator (the second harmonic 2f operates in TM mode). 020 Mode, third harmonic 3f operating in TM 030 (Coaxial resonant cavity of the mode).

[0053] Based on this, three hybrid mode resonant cavities (f-2f, f-3f, 2f-3f) operating in any band are designed. Then, according to the technical specifications of the klystron, such as operating voltage, operating current, bead waist radius, number of beads, etc., the cavity frequency, cavity position and external quality factors of the input and output cavities are optimized to obtain the working performance of the klystron, such as efficiency, gain, peak power, etc.

[0054] Therefore, this invention designs three schemes using hybrid-mode resonators: all three schemes adopt the clustered center stabilization method (CSM) and respectively employ three combinations of hybrid-mode resonators (f-2f, f-3f, 2f-3f). The klystron performance obtained by design optimization in the large-signal computer software KlyC confirms the feasibility of using the hybrid-mode resonator method in the design of high-efficiency CSM klystrons.

[0055] Example

[0056] like Figures 1 to 12 As shown, the present invention discloses a method for realizing a high-efficiency compact klystron based on a hybrid-mode resonant cavity, the method comprising:

[0057] Based on the cluster center stabilization method (CSM), three combinations of hybrid mode resonators are used to design and optimize the klystron performance using the large-signal computer software KlyC. This method requires only 5 resonators when introducing one higher harmonic cavity or only 6 resonators when introducing two higher harmonic cavities.

[0058] As a further implementation, the three combinations of hybrid mode resonators include a first hybrid mode resonator, a second hybrid mode resonator, and a third hybrid mode resonator; specifically, a first hybrid mode (fundamental-second harmonic hybrid mode, f-2f) resonator, a second hybrid mode (fundamental-third harmonic hybrid mode, f-3f) resonator, and a third hybrid mode (second harmonic hybrid mode-third harmonic hybrid mode, 2f-3f) resonator; wherein, the first hybrid mode can operate at both the fundamental frequency and the second harmonic frequency, the second hybrid mode can operate at both the fundamental frequency and the third harmonic frequency, and the third hybrid mode can operate at both the second harmonic frequency and the third harmonic frequency.

[0059] In this embodiment, the first hybrid mode resonant cavity refers to the fundamental frequency f operating in TM mode. 010 Mode, second harmonic 2f operating in TM 020 The first type is a coaxial resonant cavity with a specific mode; the second type is a hybrid mode resonant cavity referring to a cavity where the fundamental frequency f operates in the TM mode. 010 Mode, third harmonic 3f operating in TM 030The third type of hybrid mode resonator refers to the coaxial resonator operating at the TM mode. 020 Mode, third harmonic 3f operating in TM 030 Coaxial resonant cavity of mode.

[0060] in, Figure 1 For TM 010 model, Figure 2 For TM 020 model, Figure 3 For TM 030 model.

[0061] As a further implementation, the methods for obtaining the three combinations of the hybrid mode resonator are as follows:

[0062] Based on the standard cylindrical resonant cavity in TM nip The expression for the resonant frequency of the mode is used to obtain the relationship between the resonant frequencies of the fundamental wave in the three modes.

[0063] Based on the relationship between the resonant frequencies of the fundamental wave in the three modes, the resonant cavity is optimized to obtain the resonant cavity of the first hybrid mode, the resonant cavity of the second hybrid mode, and the resonant cavity of the third hybrid mode.

[0064] The relationship between the resonant frequencies of the three modes includes the second harmonic 2f operating in TM. 020 Mode and fundamental frequency f operating in TM 010 The ratio of the resonant frequencies of the modes, the third harmonic 3f operating in TM 030 Mode and fundamental frequency f operating in TM 010 The ratio of the resonant frequencies of the modes, the third harmonic 3f operating in TM 030 Mode and second harmonic 2f operating in TM 020 The ratio of the resonant frequencies of the modes.

[0065] In this embodiment, the resonant cavity is optimized, specifically as follows:

[0066] By adjusting the inner diameter D-IN of the coaxial resonant cavity to reduce the difference in the multiple relationship between the fundamental wave and higher harmonics, and then changing the outer diameter a of the resonant cavity and the diameter D-gap of the resonant cavity gap, the desired frequency can be obtained, that is, the resonant cavity of the first mixed mode, the resonant cavity of the second mixed mode, and the resonant cavity of the third mixed mode are obtained.

[0067] As a further implementation, the standard cylindrical resonant cavity in TM nip The expression for the resonant frequency of the mode is:

[0068]

[0069] In the formula, c is the speed of light, n, i, and p are subscripts in the corresponding modes, l is the length of the resonant cavity, a is the radius of the resonant cavity, and p ni Let be the i-th root of the n-th Bessel function.

[0070] In practical implementation, the technical specifications of the multi-beam klystron are as follows: operating in the L-band (operating frequency 1.3GHz), incorporating 6 electron beams, each beam operating voltage 110KV, each beam operating current 28A, and beam waist radius 6.5mm. Using the cluster center stabilization method (CSM method), three coaxial resonator schemes operating in hybrid mode were designed.

[0071] It should be noted that the main component of the high-frequency interaction system of a multi-beam klystron is the high-frequency resonant cavity. When selecting the operating mode of the resonant cavity, the electric field at the cavity gap of that mode needs to be considered. The larger the component of the electric field at the gap along the z-direction (i.e., the direction of electron beam motion), the higher the energy exchange efficiency between the electric field and the electron beam, which enables the klystron to achieve higher efficiency.

[0072] 1. The first option (ff f-2f ff): such as Figure 4 As shown, five resonant cavities are used. The first resonant cavity serves as the input cavity, the fifth resonant cavity as the output cavity, and the three middle resonant cavities are all cluster cavities. The third resonant cavity operates in the first hybrid mode (fundamental frequency f-TM). 010 and second harmonic 2f-TM 020 The remaining resonant cavities all use the fundamental frequency f operating in a single mode (fundamental frequency f-TM). 010 Based on the field distribution of the input cavity, cluster cavity, and output cavity, the cavity frequency, cavity position, and external quality factors of the input and output cavities were optimized in the large-signal computer software KlyC to obtain the working performance of the first klystron: L-band, peak power of 11.48MW, gain of 47.59dB, electron beam efficiency of 62.1%, and total high-frequency interaction length <480mm.

[0073] The first type of hybrid resonant cavity refers to a coaxial resonant cavity where the fundamental frequency f operates in TM010 mode and the second harmonic 2f operates in TM020 mode; for example... Figure 4 As shown, Figure 4 It operates in TM010 mode for the fundamental frequency of 1.3 GHz and in TM020 mode for the second harmonic frequency of 2.6 GHz.

[0074] In the first option, Figure 5 The figures show the curves of current harmonics and average electron velocity as a function of longitudinal position z at different radius positions (the dashed line represents the position of the resonant cavity). Figure 5 (a) shows the curves of current harmonics versus longitudinal position at different radius positions (dashed lines represent the positions of the resonant cavity). Figure 5 In (a), the horizontal axis represents the distribution of the high-frequency structure of the klystron along the longitudinal direction z, and the vertical axis represents the first-order current harmonics. Figure 5 (b) Curves showing the variation of the average electron velocity with longitudinal position at different radii (the dashed line represents the position of the resonant cavity). Figure 5 (b) The horizontal axis represents the distribution of the high-frequency structure of the klystron along the longitudinal direction z, and the vertical axis represents the ratio of the average electron velocity ve to the speed of light c. Figure 5 The third dashed line in the middle uses the first hybrid mode resonant cavity.

[0075] Figure 6 This is an electron phase trajectory diagram. Figure 6 The horizontal axis represents the distribution of the high-frequency structure of the klystron along the longitudinal direction z, and the vertical axis represents the electronic phase.

[0076] Specifically, based on the field distribution of the input cavity, cluster cavity, and output cavity, the cavity frequency, cavity position, and external quality factors of the input and output cavities are optimized in the large-signal computer software KlyC to obtain the operating performance of the first klystron, including:

[0077] In klystron design, the cavity frequency, cavity position, and external quality factors of the input and output cavities are initially set based on the field distribution of the input cavity, cluster cavity, and output cavity. Then, staggered tuning is performed, which optimizes the cavity frequency, cavity position, and external quality factors of the input and output cavities to obtain a more efficient design.

[0078] In the electromagnetic simulation software CST, a resonant cavity model is established and solved using the CST eigenmode solver. The solved electric fields are then sequentially imported into the large-signal computer software KlyC for staggered tuning. After obtaining preliminary results, the optimization algorithm of the large-signal computer software KlyC is used for optimization to achieve higher efficiency.

[0079] It should be noted that the large-signal computer software KlyC is a software for quickly calculating klystrons. After testing, the simulation results of KlyC are in good agreement with those of AJDisk, MAGIC and CST.

[0080] 2. Second scheme (ff f-2f f-3f ff): This scheme uses six resonant cavities. The first resonant cavity serves as the input cavity, the sixth resonant cavity as the output cavity, and the four middle resonant cavities are all cluster cavities. The third resonant cavity operates in the first hybrid mode, the fourth resonant cavity operates in the second hybrid mode, and the remaining resonant cavities all use the fundamental frequency f operating in a single mode TM. 010The resonant cavity was designed, and based on the field distribution of the input cavity, cluster cavity, and output cavity, the cavity frequency, cavity position, and external quality factors of the input and output cavities were optimized in the large-signal computer software KlyC. The operating performance of the second klystron was obtained as follows: L-band, peak power of 12.26MW, gain of 47.87dB, electron beam efficiency of 66.34%, and total high-frequency interaction length <600mm.

[0081] The first hybrid mode resonant cavity refers to the fundamental frequency f operating in TM mode. 010 Mode, second harmonic 2f operating in TM 020 The first type is a coaxial resonant cavity with a specific mode; the second type is a hybrid mode resonant cavity referring to a cavity where the fundamental frequency f operates in the TM mode. 010 Mode, third harmonic 3f operating in TM 030 A coaxial resonant cavity in a specific mode; Figure 7 Operating at 1.3 GHz for the fundamental frequency in TM 010 Mode and third harmonic 3.9GHz operation in TM 030 model.

[0082] In the second option, Figure 8 The figures show the curves of current harmonics and average electron velocity as a function of longitudinal position z at different radius positions (the dashed line represents the position of the resonant cavity). Figure 8 (a) shows the curves of current harmonics versus longitudinal position at different radius positions (dashed lines represent the positions of the resonant cavity). Figure 8 In (a), the horizontal axis represents the distribution of the high-frequency structure of the klystron along the longitudinal direction z, and the vertical axis represents the first-order current harmonics. Figure 8 (b) Curves showing the variation of the average electron velocity with longitudinal position at different radii (the dashed line represents the position of the resonant cavity). Figure 8 (b) The horizontal axis represents the distribution of the high-frequency structure of the klystron along the longitudinal direction z, and the vertical axis represents the ratio of the average electron velocity ve to the speed of light c. Figure 8 The third dashed line in the middle uses the first hybrid mode resonator, and the fourth dashed line uses the second hybrid mode resonator.

[0083] Figure 9 This is an electron phase trajectory diagram. Figure 9 The horizontal axis represents the distribution of the high-frequency structure of the klystron along the longitudinal direction z, and the vertical axis represents the electronic phase.

[0084] 3. The third scheme (ff f-2f 2f-3f ff): uses 6 resonant cavities. The first resonant cavity is used as the input cavity, the sixth resonant cavity is used as the output cavity, and the four middle resonant cavities are all cluster cavities. Among them, the third resonant cavity operates in the first hybrid mode, the fourth resonant cavity operates in the third hybrid mode, and the remaining resonant cavities all use the fundamental frequency f operating in a single mode TM. 010The resonant cavity was designed, and based on the field distribution of the input cavity, cluster cavity, and output cavity, the cavity frequency, cavity position, and external quality factors of the input and output cavities were optimized in the large-signal computer software KlyC. The operating performance of the third klystron was obtained as follows: L-band, peak power of 12.09MW, gain of 47.81dB, electron beam efficiency of 65.42%, and total high-frequency interaction length <600mm.

[0085] The first hybrid mode resonant cavity refers to the fundamental frequency f operating in TM mode. 010 Mode, second harmonic 2f operating in TM 020 The third type of hybrid mode resonator refers to the coaxial resonator operating at the TM mode. 020 Mode, third harmonic 3f operating in TM 030 Coaxial resonant cavity of mode. Figure 10 For second harmonic 2.6GHz operation in TM 020 Mode and third harmonic 3.9GHz operation in TM 030 model.

[0086] In the third option Figure 11 The figures show the curves of current harmonics and average electron velocity as a function of longitudinal position z at different radius positions (the dashed line represents the position of the resonant cavity). Figure 11 (a) shows the curves of current harmonics versus longitudinal position at different radius positions (dashed lines represent the positions of the resonant cavity). Figure 11 In (a), the horizontal axis represents the distribution of the high-frequency structure of the klystron along the longitudinal direction z, and the vertical axis represents the first-order current harmonics. Figure 11 (b) Curves showing the variation of the average electron velocity with longitudinal position at different radii (the dashed line represents the position of the resonant cavity). Figure 11 (b) The horizontal axis represents the distribution of the high-frequency structure of the klystron along the longitudinal direction z, and the vertical axis represents the ratio of the average electron velocity ve to the speed of light c. Figure 11 The third dashed line in the middle uses the second hybrid mode resonator, and the fourth dashed line uses the third hybrid mode resonator.

[0087] Figure 12 This is an electron phase trajectory diagram. Figure 12 The horizontal axis represents the distribution of the high-frequency structure of the klystron along the longitudinal direction z, and the vertical axis represents the electronic phase.

[0088] As can be seen from the above three schemes, compared with conventional CSM, the first / second / third schemes of this invention reduce the number of resonant cavities by 1-2 while maintaining efficiency, shortening the length and reducing weight. The resonant cavity operating in hybrid mode proposed in this invention has the following beneficial effects:

[0089] (1) The structure of the klystron operating in the hybrid mode resonant cavity has high efficiency and peak power, as well as shorter length and lighter weight, which is very beneficial to the miniaturization design of the klystron.

[0090] (2) The structure of the hybrid mode resonator is simple, making the processing and assembly relatively simple;

[0091] (3) The use of a resonant cavity operating in a hybrid mode reduces the total number of resonant cavities and lowers the cost of the klystron.

[0092] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for realizing a high-efficiency compact klystron based on a hybrid-mode resonant cavity, characterized in that, The method includes: Based on the cluster center stabilization method (CSM), three combinations of hybrid mode resonators are used to optimize the klystron performance through large-signal computer software design. This method requires only 5 resonators when introducing one higher harmonic cavity or only 6 resonators when introducing two higher harmonic cavities. The three combinations of hybrid-mode resonators include a first-mode resonator, a second-mode resonator, and a third-mode resonator, wherein: The first hybrid mode resonant cavity refers to a cavity where the fundamental frequency f operates at TM. 010 Mode, second harmonic 2f operating in TM 020 The first type is a coaxial resonant cavity with a specific mode; the second type is a hybrid mode resonant cavity referring to a cavity where the fundamental frequency f operates in the TM mode. 010 Mode, third harmonic 3f operating in TM 030 The third type of hybrid mode resonator refers to the coaxial resonator operating at the second harmonic 2f mode. 020 Mode, third harmonic 3f operating in TM 030 A coaxial resonant cavity in a specific mode; The klystron's performance was obtained through three combinations of hybrid-mode resonant cavities, optimized using large-signal computer software design, including: First klystron: It uses 5 resonant cavities. The first resonant cavity is used as the input cavity, the fifth resonant cavity is used as the output cavity, and the three middle resonant cavities are all used as cluster cavities. One of the cluster cavities is a resonant cavity that operates in the first mixed mode, and the remaining resonant cavities are resonant cavities that operate in a single mode with the fundamental frequency f. The second klystron uses six resonant cavities: the first resonant cavity is used as the input cavity, the sixth resonant cavity is used as the output cavity, and the four middle resonant cavities are all used as cluster cavities. Two of the cluster cavities are resonant cavities operating in the first hybrid mode and resonant cavities operating in the second hybrid mode, respectively. The remaining resonant cavities are resonant cavities operating in a single mode with the fundamental frequency f. The third klystron employs six resonant cavities: the first resonant cavity serves as the input cavity, the sixth resonant cavity as the output cavity, and the four middle resonant cavities serve as cluster cavities. Two of these cluster cavities operate in the first hybrid mode and the third hybrid mode, respectively. The remaining resonant cavities operate in a single mode with the fundamental frequency f.

2. The method for realizing a high-efficiency compact klystron based on a hybrid-mode resonant cavity according to claim 1, characterized in that, The klystron's performance is obtained through three combinations of hybrid-mode resonant cavities, optimized using large-signal computer software design. Other methods include: The first klystron's operating performance is obtained by optimizing the cavity frequency, cavity position, and external quality factors of the input and output cavities in large-signal computer software based on the field distribution of the input cavity, cluster cavity, and output cavity. The second klystron's operating performance is obtained by optimizing the cavity frequency, cavity position, and external quality factors of the input and output cavities in large-signal computer software based on the field distribution of the input cavity, cluster cavity, and output cavity. The third klystron's performance is obtained by optimizing the cavity frequency, cavity position, and external quality factors of the input and output cavities in large-signal computer software based on the field distribution of the input cavity, cluster cavity, and output cavity.

3. The method for realizing a high-efficiency compact klystron based on a hybrid-mode resonant cavity according to claim 2, characterized in that, The operating performance of the first klystron includes: L-band, peak power of 11.48MW, gain of 47.59dB, electron beam efficiency of 62.1%, and total high-frequency interaction length <480mm.

4. The method for realizing a high-efficiency compact klystron based on a hybrid-mode resonant cavity according to claim 2, characterized in that, The operating performance of the second klystron includes: L-band, peak power of 12.26MW, gain of 47.87dB, electron beam efficiency of 66.34%, and total high-frequency interaction length <600mm.

5. The method for realizing a high-efficiency compact klystron based on a hybrid-mode resonant cavity according to claim 2, characterized in that, The operating performance of the third klystron includes: L-band, peak power of 12.09MW, gain of 47.81dB, electron beam efficiency of 65.42%, and total high-frequency interaction length <600mm.

6. The method for realizing a high-efficiency compact klystron based on a hybrid-mode resonant cavity according to claim 1, characterized in that, The methods for obtaining the three combinations of hybrid-mode resonant cavities are as follows: Based on the standard cylindrical resonant cavity The resonant frequency expression of the mode is obtained to obtain TM. 010 Pattern, TM 020 Pattern, TM 030 The relationship between the resonant frequencies of the modes; Based on the relationship between the resonant frequencies of the three modes, the resonant cavity is optimized to obtain the resonant cavity of the first hybrid mode, the resonant cavity of the second hybrid mode, and the resonant cavity of the third hybrid mode. The relationship between the resonant frequencies of the three modes includes the second harmonic 2f operating in TM. 020 Mode and fundamental frequency f operating in TM 010 The ratio of the resonant frequencies of the modes, the third harmonic 3f operating in TM 030 Mode and fundamental frequency f operating in TM 010 The ratio of the resonant frequencies of the modes, the third harmonic 3f operating in TM 030 Mode and second harmonic 2f operating in TM 020 The ratio of the resonant frequencies of the modes.

7. The method for realizing a high-efficiency compact klystron based on a hybrid-mode resonant cavity according to claim 6, characterized in that, A standard cylindrical resonant cavity in The expression for the resonant frequency of the mode is: ； In the formula, c is the speed of light, n, i, and p are subscripts in the corresponding modes, l is the length of the resonant cavity, a is the radius of the resonant cavity, and p ni Let be the i-th root of the n-th Bessel function.

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