Electron beam accelerating tube and electron beam accelerator

Abstract

The invention discloses an electron beam accelerating tube and an electron beam accelerator, and relates to the technical field of electron beam accelerators. The electron beam accelerating tube comprises a first cavity and a suppression cavity, a first electromagnetic field can be generated in the first cavity, the first cavity is used for accelerating an electron beam emitted by an electron gun through the first electromagnetic field, and a leakage field is formed in the first electromagnetic field; the suppression cavity is arranged between the first cavity and the electron gun, a second electromagnetic field is built in the suppression cavity through the leakage field, the intensity of the second electromagnetic field is higher than that of the leakage field, and the second electromagnetic field is used for suppressing electrons in the electron beam from moving towards the electron gun. By applying the electron beam accelerating tube disclosed by the invention, the back bombardment phenomenon of electrons to the electron gun can be reduced, and the use performance and the service life of the electron gun are improved.

Description

Technical Field

[0001] The present application relates to but is not limited to the technical field of electron beam accelerators, and in particular to an electron beam accelerating tube and an electron beam accelerator. Background Art

[0002] In a microwave electron gun, the interaction between the electron beam and the microwave field may cause some electrons to be reflected back to the cathode of the electron gun, resulting in electron back-bombardment, which can damage and evaporate the cathode material of the electron gun, seriously affecting the performance and life of the electron gun.

[0003] In the prior art, the beam bounce problem is improved by optimizing the structure of the first cavity of the accelerating tube. However, the bounced electron beam hitting the nose cone of the first cavity for a long time will still change the internal structure of the nose cone, affecting the acceleration field shape established by the first cavity, thereby adversely affecting the acceleration of the electron beam. Summary of the invention

[0004] In order to solve the above problems, the electron beam accelerating tube provided in the present application can reduce the electron bombardment phenomenon of the electron gun and improve the performance and life of the electron gun.

[0005] In a first aspect, the present application provides an electron beam accelerating tube, which includes a first cavity and a suppression cavity. A first electromagnetic field can be generated inside the first cavity, and the first cavity is used to accelerate an electron beam emitted by an electron gun through the first electromagnetic field, and the first electromagnetic field forms a leakage field; the suppression cavity is arranged between the first cavity and the electron gun, and the suppression cavity establishes a second electromagnetic field inside it through the leakage field, and the intensity of the second electromagnetic field is higher than the intensity of the leakage field, and the second electromagnetic field is used to suppress the electrons in the electron beam from moving toward the electron gun.

[0006] The electron beam accelerating tube provided in the present application can generate a first electromagnetic field inside the first cavity for accelerating the electron beam emitted by the electron gun. Due to the physical structure of the first cavity, material properties, and the distribution of the electric field itself, the first electromagnetic field in the first cavity will leak. The first electromagnetic field may "leak" from the inside of the first cavity to the outside of the first cavity to form a leakage field, so that some electrons in the electron beam are subjected to a force in the direction of the electron gun, and there is a risk of being bombarded back to the electron gun. Since the suppression cavity is arranged between the first cavity and the electron gun, the suppression cavity can use the leakage field to establish a second electromagnetic field in the suppression cavity. The direction of the second electromagnetic field is opposite to the direction of the leakage field toward the electron gun, which can provide a force in the opposite direction for the electrons in the electron beam that are bombarded back, and the intensity of the second electromagnetic field is higher than the intensity of the leakage field. Therefore, the second electromagnetic field can offset and overcome the force of the leakage field on the electrons, thereby suppressing the movement of electrons toward the electron gun and reducing the phenomenon of electrons bombarding the electron gun.

[0007] In a possible implementation of the present application, the suppression cavity uses a high dielectric constant material to suppress thermal deformation of the suppression cavity.

[0008] In a possible implementation of the present application, the radial dimension of the suppression cavity is smaller than the radial dimension of the first cavity; and the axial dimension of the suppression cavity is smaller than the axial dimension of the first cavity.

[0009] In a possible implementation of the present application, the suppression cavity includes a first beam hole and a second beam hole, the first beam hole is connected to the electron gun, the second beam hole is connected to the first cavity, and the radial size of the second beam hole is greater than the radial size of the first beam hole.

[0010] In a possible implementation of the present application, the first cavity includes a third beam hole, the third beam hole is coupled to the second beam hole, and the third beam hole has the same size as the second beam hole.

[0011] In a possible implementation of the present application, the suppression cavity includes a first nose cone and a second nose cone; the first nose cone is arranged circumferentially around the first beam hole, and the second nose cone is arranged circumferentially around the second beam hole; the first nose cone and the second nose cone are both recessed toward the interior of the suppression cavity so that the inner surfaces of the first nose cone and the second nose cone are close to each other.

[0012] In a possible implementation of the present application, the first nose cone has a first bottom surface along the radial direction of the first beam hole, the second nose cone has a second bottom surface along the radial direction of the second beam hole, and the area of ​​the first bottom surface is greater than that of the second bottom surface.

[0013] In a possible implementation of the present application, the edges of the first nose cone, the second nose cone, and the suppression cavity are all rounded transitions.

[0014] In a possible implementation of the present application, the electron beam accelerating tube further includes a coupling cavity and an accelerating cavity, and the first cavity, the coupling cavity and the accelerating cavity are connected through a coupling hole; the coupling hole is eccentrically arranged relative to the central axis of the first cavity; the accelerating cavity is used to accelerate the electron beam.

[0015] In a second aspect, the present application provides an electron beam accelerator, which includes an electron gun and any one of the electron beam accelerating tubes described above, wherein a suppression chamber of the electron beam accelerating tube is connected to the electron gun.

[0016] The electron beam accelerator provided in the present application comprises any one of the electron beam accelerating tubes described above, and therefore has the same technical effect as the electron beam accelerating tubes described above, namely, it can reduce the electron bombardment phenomenon on the electron gun and improve the performance and life of the electron gun. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the structure of an electron beam accelerator provided in an embodiment of the present application;

[0018] Figure 2 A schematic diagram of the partial structure of an electron beam accelerating tube provided in an embodiment of the present application;

[0019] Figure 3 A front view of the suppression chamber of the electron beam accelerating tube provided in an embodiment of the present application;

[0020] Figure 4 A rear view of the suppression chamber of the electron beam accelerating tube provided in an embodiment of the present application;

[0021] Figure 5 Provided in the embodiments of this application Figure 4 Cutaway view from medium AA perspective;

[0022] Figure 6 A schematic diagram of the internal structure of the first cavity of the electron beam accelerating tube provided in an embodiment of the present application.

[0023] Reference numerals:

[0024] 1-electron beam accelerating tube; 11-first cavity; 111-third beam hole; 112-fourth beam hole; 12-suppression cavity; 121-first beam hole; 122-second beam hole; 123-first nose cone; 1231-first bottom surface; 124-second nose cone; 1241-second bottom surface; 13-coupling cavity; 14-accelerating cavity; 15-coupling hole; 2-electron gun; 21-cathode; 3-waveguide. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the specific technical solution of the present application will be further described in detail below in conjunction with the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application, but are not used to limit the scope of the present application.

[0026] In the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more.

[0027] In addition, in the embodiments of the present application, directional terms such as "up", "down", "left" and "right" are defined relative to the orientation of the components in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they may change accordingly according to the changes in the orientation of the components in the drawings.

[0028] In the embodiments of the present application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0029] In the embodiments of the present application, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0030] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0031] The working principle of microwave electron beam accelerator is based on the interaction between microwaves and electrons. The microwave power source generates microwave energy and transmits the microwave energy to the electron beam accelerator tube through the waveguide system. In the electron beam accelerator tube, the microwave electromagnetic field accelerates the electrons on the one hand, so that the electrons obtain high energy, and on the other hand, it is used to constrain and focus the electron beam so that the electrons can move along a predetermined trajectory.

[0032] Microwave electron beam accelerators generally include microwave power source, waveguide system, acceleration cavity, magnet system and electron gun, etc. Among them, microwave power source is used to generate microwave energy; waveguide system is used to transmit microwave energy from microwave power source to acceleration cavity, which is helpful for efficient energy transfer; electron beam acceleration tube is the main area of ​​electron acceleration, and electron gun is used to emit electrons, which is the starting part of microwave electron beam accelerator.

[0033] Reference Figure 1 An embodiment of the present application provides an electron beam accelerator, which includes an electron gun 2 and an electron beam accelerating tube 1 , wherein a suppression cavity 12 of the electron beam accelerating tube 1 is connected to the electron gun 2 .

[0034] In the embodiment of the present application, the cathode 21 of the electron gun 2 is used to generate a high energy density electron beam. The cathode 21 of the electron gun 2 is usually made of a high melting point metal (such as tungsten) and is heated to emit electrons.

[0035] In the microwave electron gun 2, the interaction between the electron beam and the microwave electromagnetic field may cause part of the electrons to be reflected back to the cathode 21 of the electron gun 2, resulting in electron back-bombardment. This back-bombardment phenomenon may damage and evaporate the material of the cathode 21 of the electron gun 2, seriously affecting the performance and life of the electron gun 2.

[0036] In the prior art, the first cavity 11 of the accelerating tube is optimized to a certain extent, the lower side of the first cavity beam has no nose cone, the interior of the downstream side is a smooth surface, the center of the downstream side of the first cavity is connected to the downstream beam channel of the first cavity, and the other end of the downstream beam channel of the first cavity is connected to the upstream side of the second cavity. This structure can make the reverse electron beam disperse when it moves in the upstream channel of the first cavity beam, and hit the nose cone and the beam hole gradient section, which better improves the problem of beam back-bombardment. However, the electron beam back-bombarded by this scheme hits the nose cone of the first cavity 11 for a long time, which will change the internal structure of the nose cone, thereby affecting the acceleration field shape established by the first cavity 11, and having a certain impact on the acceleration of the electron beam.

[0037] Reference Figure 1 and Figure 2 The embodiment of the present application provides an electron beam accelerating tube 1, which includes a first cavity 11 and a suppression cavity 12. A first electromagnetic field can be generated inside the first cavity 11. The first cavity 11 is used to accelerate the electron beam emitted by the electron gun 2 through the first electromagnetic field, and the first electromagnetic field forms a leakage field; the suppression cavity 12 is arranged between the first cavity 11 and the electron gun 2, and the suppression cavity 12 establishes a second electromagnetic field inside it through the leakage field, and the intensity of the second electromagnetic field is higher than the intensity of the leakage field, and the second electromagnetic field is used to suppress the electrons in the electron beam from moving toward the electron gun 2.

[0038] In the embodiment of the present application, microwave power is fed into the electron beam accelerating tube 1 through the input waveguide 3 , and is continuously reflected in the electron beam accelerating tube 1 , and finally forms a first electromagnetic field in the first cavity 11 .

[0039] In the embodiment of the present application, the shape, size and material of the first cavity 11 can be adjusted according to the requirements, and the present application does not limit this. For example, in the embodiment provided by the present application, the shape of the first cavity 11 is a cylindrical cavity with a short axial dimension, and the circumferential surface is arc-processed, and the material of the first cavity 11 is generally metal copper.

[0040] In an embodiment of the present application, the suppression cavity 12 uses a high dielectric constant material, which may include perovskite structured ceramic materials such as barium titanate (BaTiO3) and lead titanate (PbTiO3), and complex oxide ceramics such as potassium sodium niobate (KNN), which is not limited in the present application.

[0041] The electron beam accelerating tube 1 of the embodiment of the present application can generate a first electromagnetic field inside the first cavity 11 for accelerating the electron beam emitted by the electron gun 2. Due to the physical structure, material properties and distribution of the electric field of the first cavity 11, the first electromagnetic field in the first cavity 11 may "leak". The first electromagnetic field may "leak" from the inside of the first cavity 11 to the outside of the first cavity 11, thereby forming a leakage field, causing some electrons in the electron beam to be subjected to a force in the direction of the electron gun 2, and there is a risk of being bombarded back to the electron gun 2.

[0042] Since the suppression cavity 12 is disposed between the first cavity 11 and the electron gun 2, the suppression cavity 12 can use the leakage field to establish a second electromagnetic field in the suppression cavity 12. The direction of the second electromagnetic field is opposite to the direction of the leakage field toward the electron gun 2, and can provide a force in the opposite direction for the electrons in the electron beam that are bombarded back. Furthermore, because the intensity of the second electromagnetic field is higher than the intensity of the leakage field, the second electromagnetic field can offset and overcome the force of the leakage field on the electrons, thereby suppressing the movement of the electrons toward the electron gun 2 and reducing the phenomenon of electron bombardment on the electron gun 2.

[0043] In some possible embodiments of the present application, the suppression cavity is made of a high dielectric constant material to suppress thermal deformation of the suppression cavity.

[0044] Materials with high dielectric constants have a lower quality factor (Quality Factor, Q), that is, a lower Q value, and a higher attenuation coefficient, which helps to improve the heat resistance and stability of the suppression cavity 12, making the suppression cavity 12 better in heat resistance than the metal copper cavity, and can effectively suppress the thermal deformation caused by the electron bombardment on the cavity wall, thereby better maintaining the field shape of the second electromagnetic field in the suppression cavity 12 and enhancing the stability of the electron beam transmission process.

[0045] Reference Figure 1 and Figure 2 In some possible embodiments of the present application, the radial dimension of the suppression cavity 12 is smaller than the radial dimension of the first cavity 11 .

[0046] In the embodiment of the present application, because the suppression cavity 12 is made of a high dielectric constant material, reducing the size of the suppression cavity 12 can make the eigenfrequency of the suppression cavity 12 consistent with that of the first cavity 11, thereby improving the working stability.

[0047] In the embodiment of the present application, the radial dimension of the suppression cavity 12 is smaller than the radial dimension of the first cavity 11. Specifically, the present application does not limit the difference in radial dimension between the suppression cavity 12 and the first cavity 11, and it can be adjusted according to different requirements.

[0048] In the embodiment of the present application, since the suppression cavity 12 is disposed between the electron gun 2 and the first cavity 11, after the electron beam is emitted from the electron gun 2, it first enters the suppression cavity 12 and then enters the first cavity 11, that is, the electron beam line passes through the second electromagnetic field and then is transmitted to the first electromagnetic field. In this way, the second electromagnetic field can first optimize the transmission of the electron beam and reduce the phenomenon of electron back bombardment.

[0049] Furthermore, the electrons bombarded back from the first cavity 11 (i.e., the first electromagnetic field) to the electron gun 2 will move in the direction from the first cavity 11 to the electron gun 2, and when the electrons move into the suppression cavity 12, under the action of the axial and radial forces of the second electromagnetic field in the suppression cavity 12, the electrons accelerated along the axial direction of the suppression cavity 12 are defocused laterally (i.e., along the axial direction of the suppression cavity 12), and then hit the cavity wall of the suppression cavity 12 on the side close to the electron gun 2, thereby reducing the number of reverse bombardment electrons (i.e., electrons moving in the direction of the electron gun 2); the energy of the electrons decelerated along the radial direction of the suppression cavity 12 is reduced, thereby reducing the energy of the reverse bombardment particles, thereby suppressing the electron reverse bombardment in both the axial and radial directions of the suppression cavity 12.

[0050] In the electron beam accelerating tube 1 of the embodiment of the present application, the radial dimension of the suppression cavity 12 is smaller than that of the first cavity 11, which makes the distribution of the second electromagnetic field (i.e., the electromagnetic field in the suppression cavity 12) more compact than that of the first electromagnetic field (i.e., the electromagnetic field in the first cavity 11). As a result, the phase velocity of the electromagnetic wave propagating in the suppression cavity 12 is closer to the velocity of electrons emitted by the electron gun 2. This closeness of the phase velocity to the electron velocity helps to optimize the performance of the electron beam, reduce the scattering and energy loss of the electron beam in the suppression cavity 12, and improve the stability and focusing of the electron beam.

[0051] Reference Figure 1 and Figure 2 In some possible embodiments of the present application, the axial dimension of the suppression cavity 12 is smaller than the axial dimension of the first cavity 11 .

[0052] In the embodiment of the present application, the axial dimension of the suppression cavity 12 depends on the energy of the electrons emitted by the electron gun 2 . The greater the energy of the electrons emitted by the electron gun 2 , the longer the axial dimension of the suppression cavity 12 .

[0053] In the electron beam accelerating tube 1 of the embodiment of the present application, the axial dimension of the suppression cavity 12 is smaller than the axial dimension of the first cavity 11. It can be understood that the transmission path of the electron beam in the suppression cavity 12 is shorter than the transmission path in the first cavity 11, which helps to reduce the diffusion and energy loss of the electron beam during the transmission process, thereby improving the focusing performance of the electron beam.

[0054] Reference Figure 3 , Figure 4 and Figure 5In some possible embodiments of the present application, the suppression cavity 12 includes a first beam hole 121 and a second beam hole 122. The first beam hole 121 is connected to the electron gun 2, and the second beam hole 122 is connected to the first cavity 11. The radial dimension of the second beam hole 122 is greater than the radial dimension of the first beam hole 121.

[0055] In the embodiment of the present application, the first beam hole 121 and the second beam hole 122 are coaxially arranged with the suppression cavity 12, and are arranged on two opposite sides of the suppression cavity 12 in the axial direction. The present application does not limit the specific sizes of the first beam hole 121 and the second beam hole 122, which can be adjusted according to needs.

[0056] In the embodiment of the present application, the first beam hole 121 is connected to the electron gun 2 through a drift section, which reduces the radial size of the first beam hole 121 and effectively reduces the electromagnetic field propagating from the suppression cavity 12 toward the electron gun 2, thereby reducing the interference to the electrons of the electron gun 2 after being drawn out from the anode and enhancing the stability of the beam transmission.

[0057] In the embodiment of the present application, the second beam hole 122 is used to connect with the first cavity 11, and the accelerating cavities 14 are usually coupled and connected through the coupling hole 15. However, since the radial dimension of the suppression cavity 12 is relatively small, the opening position of the coupling hole 15 of the first cavity 11 connected to the suppression cavity 12 is limited. Therefore, the coupling mode is changed from magnetic coupling using the edge coupling hole 15 to electrical coupling of the beam hole coupling. Therefore, the size of the second beam hole 122 is larger than that of the first beam hole 121, which can reduce the power loss of the coupling when the second beam hole 122 and the first cavity 11 are connected.

[0058] The electron beam accelerating tube 1 of the embodiment of the present application can reduce the second electromagnetic field introduced into the electron gun 2 from the first beam hole 121, thereby reducing interference with electrons inside the electron gun 2, reducing fluctuations and deviations of the electron beam, and helping to maintain the stability of the electron beam during transmission.

[0059] Reference Figure 3 , Figure 4 , Figure 5 and Figure 6 In some possible embodiments of the present application, the first cavity 11 includes a third beam hole 111 , the third beam hole 111 is coupled to the second beam hole 122 , and the third beam hole 111 has the same size as the second beam hole 122 .

[0060] In the embodiment of the present application, the third beam hole 111 of the first cavity 11 is connected to the second beam hole 122 of the suppression cavity 12. The electron beam is transmitted from the second beam hole 122 of the suppression cavity 12 to the third beam hole 111 of the first cavity 11. After being accelerated by the first electromagnetic field in the first cavity 11, the electron beam passes through the fourth beam hole 112 of the first cavity 11 to reach the next cavity.

[0061] In the embodiment of the present application, the first cavity 11 further includes a fourth beam hole 112 arranged opposite to the third beam hole 111 , the radial dimension of the fourth beam hole 112 is smaller than the radial dimension of the third beam hole 111 , and the fourth beam hole 112 is used to connect with the next cavity.

[0062] In the electron beam accelerating tube 1 of the embodiment of the present application, since the third beam hole 111 and the second beam hole 122 have the same size, the electron beam can maintain a relatively consistent beam diameter when it is transmitted from the suppression cavity 12 to the first cavity 11, thereby reducing the electron beam diffusion and energy loss caused by the change in the beam hole size. At the same time, the third beam hole 111 and the second beam hole 122 with the same size enable better matching and coupling between the suppression cavity 12 and the first cavity 11, thereby enhancing the stability between the suppression cavity 12 and the first cavity 11.

[0063] Reference Figure 3 , Figure 4 and Figure 5 In some possible embodiments of the present application, the suppression cavity 12 includes a first nose cone 123 and a second nose cone 124; the first nose cone 123 is circumferentially arranged around the first beam hole 121, and the second nose cone 124 is circumferentially arranged around the second beam hole 122; the first nose cone 123 and the second nose cone 124 are both recessed toward the interior of the suppression cavity 12 so that the inner surfaces of the first nose cone 123 and the second nose cone 124 are close to each other.

[0064] In the embodiment of the present application, the first nose cone 123 is arranged around the first beam hole 121. The first nose cone 123 can focus the electron beam so that the electron beam can stably pass through the first beam hole 121 and reduce energy loss during transmission. The first nose cone 123 can also withstand reverse accelerated electrons and reduce the outflow of electrons from the first beam hole 121. The inner surfaces of the first nose cone 123 and the second nose cone 124 are close to each other, which can optimize the shape of the accelerating electric field established in the suppression cavity 12.

[0065] In the embodiment of the present application, the first nose cone 123 and the second nose cone 124 are both recessed toward the inside of the suppression cavity 12. The recessed shape may be a cone or a similar shape. The recessed structure may optimize the field shape of the second point magnetic field in the suppression cavity 12, so that the forward accelerated electrons (i.e., the electrons accelerated by the electron gun 2 toward the first cavity 11) are focused, and the reverse accelerated electrons (i.e., the electrons bombarded back from the first cavity 11 toward the electron gun 2) are defocused. The reverse electrons will eventually hit the first nose cone 123 and be intercepted by the first nose cone 123, thereby achieving the effect of suppressing the electron back bombardment.

[0066] Reference Figure 3 , Figure 4 and Figure 5In some possible embodiments of the present application, the first nose cone 123 has a first bottom surface 1231 along the radial direction of the first beam hole 121, and the second nose cone 124 has a second bottom surface 1241 along the radial direction of the second beam hole 122, and the area of ​​the first bottom surface 1231 is greater than the area of ​​the second bottom surface 1241.

[0067] In the embodiment of the present application, since the first nose cone 123 and the second nose cone 124 are both formed by being recessed toward the inside of the suppression chamber 12, the first nose cone 123 and the second nose cone 124 have two surfaces arranged opposite to each other inside the suppression chamber 12, the first bottom surface 1231 can be understood as the inner surface of the first nose cone 123 facing the second nose cone 124, and the second bottom surface 1241 can be understood as the inner surface of the second nose cone 124 facing the first nose cone 123. The first bottom surface 1231 and the second bottom surface 1241 can form a focusing electric field, reduce the scattering of electrons, and stably transmit the electron beam from the second beam hole to the next section of the acceleration chamber.

[0068] In the embodiment of the present application, since the first nose cone 123 is circumferentially arranged around the first beam hole 121, the first beam hole 121 is connected to the electron gun 2. When the area of ​​the first bottom surface 1231 of the first nose cone 123 is larger, it can withstand more reverse accelerated electrons (that is, electrons bombarded back from the first cavity 11 toward the electron gun 2), thereby reducing the outflow of electrons from the first beam hole 121.

[0069] In the embodiment of the present application, since the second nose cone 124 is circumferentially arranged around the second beam hole 122, the second beam hole 122 is connected to the first cavity 11. When the area of ​​the second bottom surface 1241 of the second nose cone 124 is small, the scattering of electrons can be reduced, so that the electron beam can be stably transmitted from the second beam hole 122 to the next acceleration cavity 14.

[0070] Reference Figure 3 , Figure 4 and Figure 5 In some possible embodiments of the present application, the edges of the first nose cone 123 , the second nose cone 124 , and the suppression cavity 12 are all rounded transitions.

[0071] In the embodiment of the present application, the size and shape of the fillet can be determined according to the specific requirements of the device and the working environment. The design of the fillet transition is coordinated with the shapes and sizes of other components to improve the overall performance and stability of the electron beam accelerating tube 1.

[0072] In the embodiment of the present application, the edges of the first nose cone 123, the second nose cone 124 and the suppression cavity 12 refer to the edges of the transition between the first nose cone 123, the second nose cone 124 and the gas inner wall of the suppression cavity 12 inside the suppression cavity 12. These edges are rounded transitions that can optimize the streamlines of the inner wall of the suppression cavity 12 and suppress the electrical breakdown caused by the tip effect.

[0073] In the embodiment of the present application, when there are sharp edges between the first nose cone 123, the second nose cone 124 and the suppression cavity 12, the electron beam may be affected by the uneven electric field or magnetic field, causing the trajectory of the electron beam to deviate. Compared with before, the rounded transition can provide a smooth transition area, allowing the electron beam to pass more stably and reduce scattering.

[0074] In the electron beam accelerating tube 1 of the embodiment of the present application, the edges of the first nose cone 123, the second nose cone 124 and the suppression cavity 12 are all rounded transitions, which can suppress the electrical breakdown caused by the tip effect, thereby providing a more stable acceleration environment and facilitating the stable transmission of the electron beam.

[0075] Reference Figure 5 and Figure 6 In some possible embodiments of the present application, the electron beam accelerating tube 1 further includes a coupling cavity 13 and an accelerating cavity 14; the first cavity 11, the coupling cavity 13 and the accelerating cavity 14 are connected via a coupling hole 15; the coupling hole 15 is eccentrically arranged relative to the central axis of the first cavity 11; the accelerating cavity 14 is used to accelerate the electron beam.

[0076] In the embodiment of the present application, the first cavity 11 and the coupling cavity 13 form a whole. Since the working mode of the standing wave accelerator is mainly the π / 2 mode, the electric field distribution in the accelerating tube has a specific periodicity under the π / 2 mode. The electric field phases in two adjacent accelerating cavities 14 differ by π / 2, that is, half a period. This electric field distribution enables electrons to obtain stable acceleration when passing through the accelerating cavity 14. Therefore, the electric field is excited in the first cavity 11, and under the π / 2 mode, the electric field is mainly distributed in the first cavity 11, providing the energy required for acceleration of the beam. The magnetic field is mainly distributed near the coupling hole 15, which is used to realize the power coupling between the first cavity 11, the coupling cavity 13 and the accelerating cavity 14. This distribution pattern helps to achieve efficient beam acceleration and power transmission.

[0077] In the embodiment of the present application, the coupling hole 15 is eccentrically arranged relative to the central axis of the first cavity 11, that is, the coupling hole 15 and the first cavity 11 are not coaxial, and the coupling hole 15 is arranged in a region away from the axis of the first cavity 11, and the coupling hole 15 can couple the power between cavities through a magnetic field. The coupling hole 15 couples power from a first cavity 11 to the accelerating cavity 14 through a magnetic field, which helps to maintain the stability and efficiency of the electron beam accelerating tube 1. Through the coupling hole 15, energy can be efficiently transferred between the first cavity 11 and the accelerating cavity 14, thereby achieving continuous acceleration of the electron beam.

[0078] In the embodiment of the present application, the strength and efficiency of the coupling between the first cavity 11 and the acceleration cavity 14 depend on multiple factors, including the size, shape, and position of the coupling hole 15 and the relative position and distance between the cavities.

[0079] The electron beam accelerating tube 1 of the embodiment of the present application realizes efficient coupling of power between cavities, which not only improves the stable acceleration of electrons when passing through the accelerating cavity 14, but also optimizes the power transfer efficiency between the first cavity 11 and the accelerating cavity 14 through the eccentrically arranged coupling hole 15.

[0080] The serial numbers of the embodiments of the present application are only for description and do not represent the advantages and disadvantages of the embodiments. The above are only preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An electron beam accelerating tube, characterized in that: include: A first cavity, in which a first electromagnetic field can be generated, the first cavity is used to accelerate the electron beam emitted by the electron gun through the first electromagnetic field, and the first electromagnetic field forms a leakage field; A suppression cavity is arranged between the first cavity and the electron gun. The suppression cavity establishes a second electromagnetic field inside the suppression cavity through the leakage field. The intensity of the second electromagnetic field is higher than that of the leakage field. The second electromagnetic field is used to suppress the electrons in the electron beam from moving toward the electron gun.

2. The electron beam accelerating tube according to claim 1, characterized in that: The suppression cavity is made of a high dielectric constant material to suppress thermal deformation of the suppression cavity.

3. The electron beam accelerating tube according to claim 2, characterized in that: The radial dimension of the suppression cavity is smaller than the radial dimension of the first cavity; and the axial dimension of the suppression cavity is smaller than the axial dimension of the first cavity.

4. The electron beam accelerating tube according to any one of claims 1 to 3, characterized in that: The suppression cavity comprises a first beam hole and a second beam hole, wherein the first beam hole is connected to the electron gun, the second beam hole is connected to the primary cavity, and a radial dimension of the second beam hole is greater than a radial dimension of the first beam hole.

5. The electron beam accelerating tube according to claim 4, characterized in that: The first cavity includes a third beam hole, the third beam hole is coupled to the second beam hole, and the third beam hole has the same size as the second beam hole.

6. The electron beam accelerating tube according to claim 4, characterized in that: The suppression cavity includes a first nose cone and a second nose cone; the first nose cone is arranged circumferentially around the first beam hole, and the second nose cone is arranged circumferentially around the second beam hole; the first nose cone and the second nose cone are both recessed toward the interior of the suppression cavity so that the inner surfaces of the first nose cone and the second nose cone are close to each other.

7. The electron beam accelerating tube according to claim 6, characterized in that: The first nose cone has a first bottom surface along the radial direction of the first beam hole, and the second nose cone has a second bottom surface along the radial direction of the second beam hole. The area of ​​the first bottom surface is greater than that of the second bottom surface.

8. The electron beam accelerating tube according to claim 6, characterized in that: The edges of the first nose cone, the second nose cone and the suppression cavity are all rounded transitions.

9. The electron beam accelerating tube according to claim 1, characterized in that: It also includes a coupling cavity and an accelerating cavity. The first cavity, the coupling cavity and the accelerating cavity are connected through a coupling hole. The coupling hole is eccentrically arranged relative to the central axis of the first cavity. The accelerating cavity is used to accelerate the electron beam.

10. An electron beam accelerator, characterized in that: An electron gun for generating an electron beam; The electron beam accelerating tube according to any one of claims 1 to 9, wherein the suppression chamber of the electron beam accelerating tube is connected to the electron gun.

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