Uniform permanent magnetic focusing system and multi-beam vacuum electron device

Abstract

This application discloses a uniform permanent magnet focusing system and a multi-electron-beam vacuum electronic device, relating to the field of multi-electron-beam vacuum electronic device technology. The vacuum electronic device has a first channel extending along a first direction through which the electron beam passes. The uniform permanent magnet focusing system includes a permanent magnet assembly and a pole shoe assembly. The permanent magnet assembly includes a first permanent magnet and a second permanent magnet. The pole shoe assembly includes a first pole shoe and a second pole shoe, respectively disposed at both ends of the permanent magnet assembly. Both the first and second pole shoes have main through holes extending along the first direction and communicating with the magnetic field space. A magnetic permeable portion is provided at one end of each main through hole near the permanent magnet assembly. The magnetic permeable portion has a pole shoe through hole and a magnetic permeability weakening structure. The pole shoe through hole extends radially along the main through hole, and the magnetic permeability weakening structure is used to weaken the magnetic field component perpendicular to the first direction within the pole shoe through hole. This uniform permanent magnet focusing system aims to improve the transmission flow rate of the electron beam in a multi-electron-beam vacuum electronic device.

Description

Technical Field

[0001] This application relates to the field of multi-electron-beam vacuum electronic devices, and in particular to a uniform permanent magnet focusing system and a multi-electron-beam vacuum electronic device. Background Technology

[0002] With the rapid development of high-frequency microwave and terahertz technologies, multi-electron-beam vacuum electronic devices have demonstrated irreplaceable advantages in terms of high power, high efficiency, and wide bandwidth operation. However, as the operating frequency of devices continues to increase and the demand for output power continues to grow, a single electron beam can no longer meet the power capacity requirements of modern devices, prompting multi-electron-beam parallel amplification technology to become an effective way to improve power capability. Among existing technologies, uniform permanent magnet focusing structures have been widely used in the focusing and transmission of single electron beams due to their simple structure, lack of external power supply, and high operational stability.

[0003] However, when traditional uniform permanent magnet focusing structures are directly applied to multi-electron-beam arrays, it is often difficult to obtain a stable focusing effect, resulting in low electron beam transmission efficiency in multi-electron-beam vacuum electronic devices. Summary of the Invention

[0004] The main objective of this application is to propose a uniform permanent magnet focusing system and a multi-electron-beam vacuum electronic device, which are intended to be applied to multi-electron-beam vacuum electronic devices to improve the transmission efficiency of electron beams in multi-electron-beam vacuum electronic devices.

[0005] To achieve the above objectives, the uniform permanent magnet focusing system proposed in this application is applied to a multi-electron-beam vacuum electronic device, wherein the multi-electron-beam vacuum electronic device has a first channel through which the electron beam passes and extends along a first direction, and the uniform permanent magnet focusing system includes:

[0006] A permanent magnet assembly is used to be disposed in the multi-electron-beam vacuum electronic device, including a first permanent magnet and a second permanent magnet. The first permanent magnet and the second permanent magnet are spaced apart along a second direction to form a magnetic field space between the first permanent magnet and the second permanent magnet. The first permanent magnet and the second permanent magnet have the same magnetization direction along the first direction.

[0007] The pole shoe assembly includes a first pole shoe and a second pole shoe. The first permanent magnet and the second permanent magnet each have a first end and a second end disposed opposite to each other along a first direction. The first pole shoe is disposed at the first end of the first permanent magnet and the second permanent magnet, and the second pole shoe is disposed at the second end of the first permanent magnet and the second permanent magnet. The first pole shoe and the second pole shoe each have a main through hole extending along the first direction and communicating with the magnetic field space. The main through hole of the first pole shoe, the magnetic field space, and the main through hole of the second pole shoe are distributed in the first channel.

[0008] Each of the two main through holes has a magnetic permeable portion near one end of the permanent magnet assembly. The magnetic permeable portion has a pole shoe through hole and a magnetic permeability weakening structure. The pole shoe through hole extends through the magnetic permeable portion along a first direction and extends radially along the main through hole. The magnetic permeability weakening structure is located on one side of the pole shoe through hole and is used to weaken the magnetic field component perpendicular to the first direction in the pole shoe through hole.

[0009] In one embodiment, the first permanent magnet and the second permanent magnet are cuboids, and both the first permanent magnet and the second permanent magnet have a first side surface and a second side surface that are spaced apart and opposite to each other along the second direction;

[0010] The first side of the first permanent magnet and the second side of the second permanent magnet are arranged facing each other and parallel to each other, so as to define the magnetic field space between the first side of the first permanent magnet and the second side of the second permanent magnet; wherein the second direction is perpendicular to the first direction.

[0011] In one embodiment, each of the magnetic permeable portions has two pole shoe through holes, and the two pole shoe through holes are arranged at intervals along the second direction;

[0012] Each of the magnetic permeable parts has at least two magnetic permeability weakening structures, wherein at least one of the magnetic permeability weakening structures is disposed corresponding to one of the two pole shoe through holes, and at least one of the magnetic permeability weakening structures is disposed corresponding to the other of the two pole shoe through holes.

[0013] In one embodiment, the magnetic permeability weakening structure is a through hole formed on the magnetic permeability portion; or, the magnetic permeability weakening structure is a non-magnetic material filled in the through hole formed on the magnetic permeability portion.

[0014] In one embodiment, the cross-sectional shape of the magnetic permeability weakening structure is one of a strip, an ellipse, or a circle.

[0015] In one embodiment, the two pole shoe through holes on the magnetic permeable part of the first pole shoe and the two pole shoe through holes on the magnetic permeable part of the second pole shoe are aligned one-to-one along the first direction.

[0016] At least two magnetic permeability weakening structures on the magnetic permeability portion of the first pole shoe and at least two magnetic permeability weakening structures on the magnetic permeability portion of the second pole shoe are aligned one-to-one along the first direction.

[0017] In one embodiment, both the pole shoe via and the magnetic permeability weakening structure are elongated, with the length of the magnetic permeability weakening structure being greater than the length of the pole shoe via, and / or the width of the magnetic permeability weakening structure being greater than the width of the pole shoe via.

[0018] In one embodiment, the magnetic permeable portion within the main through-hole of the first pole shoe is integrally disposed with the first pole shoe; and,

[0019] The magnetic permeable portion inside the main through hole of the second pole shoe is integrally formed with the second pole shoe.

[0020] In one embodiment, the cross-section of the main through hole of the first pole shoe and the second pole shoe is circular, and the cross-section of the magnetic permeable part is circular;

[0021] The magnetic permeable portion inside the first pole shoe faces the surface of the magnetic field space and is flush with the surface of the first pole shoe facing the magnetic field space.

[0022] The magnetic permeable portion inside the second pole shoe faces the surface of the magnetic field space and is flush with the surface of the second pole shoe facing the magnetic field space.

[0023] This application also provides a multi-electron-beam vacuum electronic device, the multi-electron-beam vacuum electronic device comprising:

[0024] The main body has a first channel through which electrons are injected and which extends in a first direction;

[0025] An electron gun, disposed on the main body, is used to emit the electron beam; and

[0026] As described above, the uniform permanent magnet focusing system is located on the main body and its position corresponds to the first channel, and it is used to magnetically focus the electron beam transmitted along the first channel.

[0027] As can be seen from the above, the uniform permanent magnet focusing system and multi-electron-beam vacuum electronic device provided in this application include a permanent magnet assembly, a pole shoe assembly, and a magnetic permeation section, wherein the magnetic permeation section has a magnetic permeation weakening structure, which is used to weaken the magnetic field component perpendicular to the first direction, thereby reducing the lateral deflection of the electron beam in the pole shoe region. It has the advantages of effectively suppressing the lateral magnetic field component and improving the transmission flow rate of the multi-electron-beam. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 A schematic diagram of a structure of an embodiment of the uniform permanent magnet focusing system provided in this application;

[0030] Figure 2A schematic diagram of another embodiment of the uniform permanent magnet focusing system provided in this application;

[0031] Figure 3 A schematic diagram of an embodiment of the pole shoe assembly provided in this application;

[0032] Figure 4 A comparison of the axial magnetic field component Bz distribution curves along the z-axis at the center of the electron beam in one embodiment before and after introducing a magnetic permeability weakening structure into the multi-electron-beam vacuum electronic device provided in this application.

[0033] Figure 5 A comparison of the distribution curves of the transverse magnetic field component Bx along the z-axis at the center of the electron beam in one embodiment before and after introducing a magnetic permeability weakening structure into the multi-electron-beam vacuum electronic device provided in this application;

[0034] Figure 6 A comparison of the By distribution curves of the transverse magnetic field component along the z-axis at the center of the electron beam in one embodiment before and after introducing a magnetic permeability weakening structure into the multi-electron-beam vacuum electronic device provided in this application.

[0035] Figure 7 A comparison diagram of the current variation with transmission distance before and after introducing a magnetic permeability weakening structure into the multi-electron-beam vacuum electronic device provided in this application;

[0036] Figure 8 A comparative schematic diagram of an embodiment showing the distribution of electron beams in the xy cross section before and after introducing a magnetic permeability weakening structure into the multi-electron-beam vacuum electronic device provided in this application;

[0037] Figure 9 After introducing a magnetic permeability weakening structure into the multi-electron-beam vacuum electronic device provided in this application, an electron envelope diagram of the electron beam in the xz and yz planes of one embodiment is shown.

[0038] Explanation of icon numbers:

[0039] 10. Uniform permanent magnet focusing system; 100. Permanent magnet assembly; 110. First permanent magnet; 120. Second permanent magnet; 200. Pole shoe assembly; 210. First pole shoe; 220. Second pole shoe; 300. Magnetic guide section; 310. Pole shoe through hole; 320. Magnetic guide weakening structure; 400. Main through hole; 500. Magnetic field space.

[0040] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0041] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0042] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution that simultaneously satisfies A and B. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0043] With the rapid development of high-frequency microwave and terahertz technologies, multi-electron-beam vacuum electronic devices have demonstrated irreplaceable advantages in terms of high power, high efficiency, and wide bandwidth operation. However, as the operating frequency of these devices continues to increase and the demand for output power grows, a single electron beam can no longer meet the power capacity requirements of modern devices, prompting multi-electron-beam parallel amplification technology to become an effective way to improve power capability. Among existing technologies, uniform permanent magnet focusing systems have been widely used for focusing and transmitting strip-shaped single-channel electron beams due to their simple structure, lack of external power supply, and high operating flux.

[0044] However, when the aforementioned uniform permanent magnet focusing system is directly applied to multi-electron-beam arrays, it is often difficult to obtain a stable and ideal focusing effect. The fundamental reason is that the multiple electron beams are arrayed in the transverse space, and some of these beams inevitably deviate from the central axis region of the uniform permanent magnet focusing system. For these electron beams deviating from the central axis, the transverse magnetic field components perpendicular to the electron beam propagation direction generated by the upper and lower permanent magnets at corresponding positions cannot cancel each other out. During the electron's propagation along the first direction, it is subjected to the transverse magnetic field, thus generating a transverse magnetic field component. This component exerts an "additional Lorentz force" on the electron, introducing a continuous transverse deflection, which in turn leads to electron beam interception and deviation from its trajectory. This deflection can accumulate throughout the propagation process, eventually causing the electron beam to be intercepted by the channel wall, reducing the electron beam throughput in multi-electron-beam vacuum electronic devices. This adverse effect is particularly pronounced when the electron beam passes through the pole shoe aperture. Changes in the magnetic circuit geometry and material permeability at the pole shoe cause a redistribution of magnetic flux in that region, deflecting the magnetic field lines from their original axial direction and forming a significant edge magnetic field. In the pole shoe via region, the transverse magnetic field experienced by the electron beam near the pole shoe reaches its peak. For electron beams deviating from the central axis, the additional Lorentz force generated by the transverse magnetic field component is greatest at this point, making their trajectory most prone to deflection or even direct interception. Therefore, the pole shoe via region becomes the most sensitive and easily unstable critical location in the focusing and stable propagation of multiple electron beams. Thus, how to effectively suppress the transverse magnetic field component experienced by the array electron beam in the critical region while maintaining the axial focusing capability of a uniform permanent magnet focusing system, and achieve stable focusing and efficient propagation of multiple electron beams, has become a crucial technical challenge that urgently needs to be addressed in this field.

[0045] Therefore, when traditional uniform permanent magnet focusing systems are directly applied to multi-electron-beam arrays, it is often difficult to obtain a stable focusing effect, resulting in low electron beam transmission efficiency in multi-electron-beam vacuum electronic devices.

[0046] To improve the electron beam transmission efficiency in multi-electron-beam vacuum electronic devices, and to achieve the aforementioned objective, this application proposes a uniform permanent magnet focusing system 10, such as... Figure 1 and Figure 2 As shown, the uniform permanent magnet focusing system 10 includes a permanent magnet assembly 100 and a pole shoe assembly 200.

[0047] The uniform permanent magnet focusing system 10 is applied to a multi-electron-beam vacuum electronic device, which has a first channel through which electrons are passed and which extends along a first direction.

[0048] The uniform permanent magnet focusing system 10 of this embodiment is applicable to multi-electron-beam vacuum electronic devices, including but not limited to traveling wave tubes, klystrons, and backward wave tubes that use strip-shaped or circular electron beams. This magnetic focusing structure is positioned between the electron gun and the collecting stage along the electron beam propagation direction. During the propagation of the electron beams after they are emitted from the electron gun and along the slow-wave circuit region, a stable magnetic field is applied to constrain the multiple electron beams, thereby achieving stable focusing and efficient propagation of the electron beams.

[0049] In this embodiment, as Figure 1 As shown, the permanent magnet assembly 100 is used to be disposed in a multi-electron-beam vacuum electronic device, including a first permanent magnet 110 and a second permanent magnet 120. The first permanent magnet 110 and the second permanent magnet 120 are spaced apart along a second direction to form a magnetic field space 500 between the first permanent magnet 110 and the second permanent magnet 120. The first permanent magnet 110 and the second permanent magnet 120 have the same magnetization direction along the first direction.

[0050] In this embodiment, as Figure 1 As shown, the pole shoe assembly 200 includes a first pole shoe 210 and a second pole shoe 220. The first permanent magnet 110 and the second permanent magnet 120 each have a first end and a second end that are arranged opposite to each other along a first direction. The first pole shoe 210 is disposed at the first end of the first permanent magnet 110 and the second permanent magnet 120, and the second pole shoe 220 is disposed at the second end of the first permanent magnet 110 and the second permanent magnet 120. The first pole shoe 210 and the second pole shoe 220 each have a main through hole 400 that extends along the first direction and communicates with the magnetic field space 500. The main through hole 400 of the first pole shoe 210, the magnetic field space 500, and the main through hole 400 of the second pole shoe 220 are distributed in the first channel.

[0051] Understandable, Figure 1 The diagram shown is a partial cross-sectional view, which means that the outer contour of the entire uniform permanent magnet focusing system 10 is square, and the missing corner part in the figure is the cut surface used to show the internal structure.

[0052] In this embodiment, a magnetic permeable portion 300 is provided at one end of each of the two main through holes 400 near the permanent magnet assembly 100. The magnetic permeable portion 300 has a pole shoe through hole 310 and a magnetic permeability weakening structure 320. The pole shoe through hole 310 extends through the magnetic permeable portion 300 along a first direction and is arranged radially along the main through hole 400. The magnetic permeability weakening structure 320 is located on one side of the pole shoe through hole 310 and is used to weaken the magnetic field component perpendicular to the first direction in the pole shoe through hole 310.

[0053] The uniform permanent magnet focusing system 10 is used to focus and transmit the electron beam. This system is typically used in multi-electron-beam vacuum electronic devices to ensure the stability of the electron beam during transmission. Optionally, multi-electron-beam vacuum electronic devices include, but are not limited to, high-frequency microwave or terahertz power amplifiers such as multi-beam traveling-wave tubes, multi-beam klystrons, or multi-beam returning-wave tubes, which employ multiple parallel strip or circular electron beam arrays to collaboratively amplify high-frequency electromagnetic signals. The uniform permanent magnet focusing system 10 provides these parallel electron beam channels with a highly consistent axial magnetic field and minimal edge distortion, effectively suppressing radial divergence of the multi-electron beam during long-distance transmission.

[0054] The permanent magnet assembly 100 is the magnetic field generating unit of the uniform permanent magnet focusing system 10. It forms a stable magnetic field distribution in a specific region through the inherent magnetism of the permanent magnet material. The configuration of the uniform permanent magnet focusing system 10 affects the strength and direction of the generated magnetic field.

[0055] The pole shoe assembly 200 is a component used to guide magnetic field lines and electron beams, and can be made of a high-permeability material. Through its geometry and material properties, the pole shoe assembly 200 shapes the magnetic field generated by the permanent magnet, enabling it to form the desired focusing field along the electron beam transmission path.

[0056] The magnetic permeable section 300 is a structure disposed within the main through-hole 400 near one end of the permanent magnet assembly 100, and its main function is to further optimize the magnetic field distribution in this region. The magnetic permeable section 300 can be made of a high-permeability material, capable of guiding magnetic field lines passing through it.

[0057] The pole shoe through-hole 310 is a through-hole on the magnetic permeability section 300, which penetrates the magnetic permeability section 300. That is, the pole shoe through-hole 310 is connected to the main through-hole 400, and the penetration direction of the pole shoe through-hole 310 on the magnetic permeability section 300 can be parallel to the axial direction of the main through-hole 400. The pole shoe through-hole 310 is elongated, and its length extends radially along the main through-hole 400. In other words, viewed from the axial direction of the main through-hole 400, the pole shoe through-hole 310 appears as an elongated through-hole. The pole shoe through-hole 310 alters the magnetic circuit inside the magnetic permeability section 300, thereby affecting the magnetic field distribution in that region, especially the magnetic field component perpendicular to the electron beam transmission direction.

[0058] The magnetic permeability weakening structure 320 is a special structure located on one side of the pole shoe through-hole 310. Its design purpose is to weaken the magnetic field component perpendicular to the first direction within the pole shoe through-hole 310. By introducing this structure, the additional Lorentz force (the Lorentz force generated by the transverse magnetic field component) experienced by the electron beam when passing through the pole shoe region can be reduced.

[0059] It is understood that the permanent magnet assembly 100 is disposed within the multi-electron-beam vacuum electronic device, and its configuration may include a first permanent magnet 110 and a second permanent magnet 120. The first permanent magnet 110 and the second permanent magnet 120 are spaced apart along a second direction, thereby forming a magnetic field space 500 between the first permanent magnet 110 and the second permanent magnet 120. The magnetization directions of the first permanent magnet 110 and the second permanent magnet 120 along the first direction are set to be the same, so as to generate a magnetic field component along the first direction within the magnetic field space 500. As one implementation, the first permanent magnet 110 and the second permanent magnet 120 may be made into a block structure and placed parallel to each other at a certain interval, and their magnetization directions may be preset. The pole shoe assembly 200 includes a first pole shoe 210 and a second pole shoe 220. The first permanent magnet 110 and the second permanent magnet 120 each have a first end and a second end disposed opposite to each other along the first direction. The first pole piece 210 is disposed at the first end of the first permanent magnet 110 and the second permanent magnet 120, while the second pole piece 220 is disposed at the second end of the first permanent magnet 110 and the second permanent magnet 120. Both the first pole piece 210 and the second pole piece 220 have main through holes 400 extending along the first direction, and these main through holes 400 communicate with the magnetic field space 500. The main through holes 400 of the first pole piece 210, the magnetic field space 500, and the main through holes 400 of the second pole piece 220 are distributed within the first channel to guide the electron beam through. Alternatively, the first pole piece 210 and the second pole piece 220 can be constructed from a flat plate structure made of a high-permeability material, with circular or rectangular through holes for the electron beam to pass through.

[0060] like Figure 1As shown, each of the two main through holes 400 has a magnetic permeable portion 300 near one end of the permanent magnet assembly 100. In one implementation, the magnetic permeable portion 300 can be a ring-shaped, columnar, or sheet-like structure made of a high-permeability material. It can be part of the first pole shoe 210 or the second pole shoe 220, i.e., integrally formed with the first pole shoe 210 and the second pole shoe 220, or it can be an independent component separate from the first pole shoe 210 or the second pole shoe 220, embedded or fixed to the inner wall of the main through hole 400. It should be noted that the magnetic permeable portion 300 has a pole shoe through hole 310 and a magnetic permeability weakening structure 320. The pole shoe through hole 310 extends radially along the main through hole 400. The arrangement of the pole shoe through hole 310 alters the magnetic circuit inside the magnetic permeable portion 300, thereby affecting the magnetic field distribution in that region. In another implementation, the pole shoe through hole 310 can be a circular, elliptical, or elongated hole that radially penetrates the magnetic permeable portion 300. The magnetic permeability weakening structure 320 is located on one side of the pole shoe through-hole 310, and its function is to weaken the magnetic field component perpendicular to the first direction within the pole shoe through-hole 310. In this way, the transverse magnetic field encountered by the electron beam when passing through the region of the pole shoe through-hole 310 can be initially suppressed.

[0061] The main through-holes 400 on the first pole piece 210 and the second pole piece 220 are used to match and install the electron gun and the collector of the multi-electron-beam vacuum electronic device, respectively. During the operation of the multi-electron-beam vacuum electronic device, the electron beam is emitted by the electron gun, first passing through the main through-hole 400 of the first pole piece 210 and entering the magnetic field space 500. After being constrained and focused by the uniform permanent magnet focusing system 10 in the magnetic field space 500, it is then emitted from the main through-hole 400 of the second pole piece 220 at the other end, and finally enters the collector for electron recovery.

[0062] It is understood that the uniform permanent magnet focusing system 10 of this embodiment, by providing a magnetic permeable portion 300 with a pole shoe through-hole 310 and a magnetic permeability weakening structure 320 within the main through-hole 400, utilizes the high magnetic reluctance shunting effect of the magnetic permeability weakening structure 320 to weaken the magnetic field component perpendicular to the electron beam transmission direction within the pole shoe through-hole 310 region. This ensures stable passage of the electron beam through the pole shoe through-hole 310, reducing the additional Lorentz force (Lorentz force generated by the transverse magnetic field component) experienced by electron beams deviating from the central axis in the multi-electron beam array when passing through the pole shoe through-hole 310 region. This suppresses the risk of electron beam trajectory deflection and interception by the channel wall, thereby improving the transmission throughput and operational stability of the multi-electron beam system.

[0063] In one feasible embodiment, the magnetic permeability weakening structure 320 can be a through hole formed on the magnetic permeability portion 300, or a non-magnetic material filler filling the through hole. Specifically, the magnetic permeability weakening structure 320 extends along a first direction (i.e., the electron beam transmission direction) and is located radially outward (i.e., peripherally) of the pole shoe through hole 310. By introducing this high magnetic reluctance region (the magnetic reluctance of air or non-magnetic materials is much higher than that of magnetic materials) to the side of the pole shoe through hole 310, the transverse magnetic field lines that originally attempted to pass through the edge of the pole shoe through hole 310 are forced to bend and detour, thereby effectively diverting the transverse magnetic flux within the pole shoe through hole 310. The position, shape, and size of the magnetic permeability weakening structure 320 can be adjusted according to the array arrangement and offset of the electron beam to achieve fine local adjustment of the magnetic field.

[0064] Among them, such as Figure 2 As shown, the magnetization directions of the first permanent magnet 110 and the second permanent magnet 120 along the first direction are set to be the same. During the magnetization manufacturing process, the magnetic moments of the first permanent magnet 110 and the second permanent magnet 120 can be controlled to be parallel to the first direction, and their polarity directions are consistent. For example, the N poles of both point to the same side of the first direction. As a result, the magnetic fields generated by the first permanent magnet 110 and the second permanent magnet 120 in the magnetic field space 500 are superimposed, thereby forming a highly uniform axial focusing magnetic field in the central region between the two permanent magnets. This axial magnetic field can effectively constrain the electron beam to propagate stably along the first path.

[0065] It is understandable that the first pole piece 210 is located at the first end of the first permanent magnet 110 and the second permanent magnet 120, while the second pole piece 220 is located at the second end of the first permanent magnet 110 and the second permanent magnet 120. Since all four are cuboids, the first permanent magnet 110 and the second permanent magnet 120 have the same shape, and the first pole piece 210 and the second pole piece 220 have the same shape. Their arrangement can be understood as a large hollow cuboid frame structure. Specifically, the first permanent magnet 110 and the second permanent magnet 120 serve as the upper and lower "cover plates" of this frame, while the first pole piece 210 and the second pole piece 220 serve as the front and rear "end caps" of the frame. The four form a physically closed annular structure through close contact, but a magnetic field space 500 for electron beams to pass through is defined at the center of this annular structure.

[0066] In summary, this application effectively solves the problem of unstable multi-electron beam transmission by setting a specially designed magnetic permeable portion 300 within the main through-hole 400 of the pole shoe assembly 200. The magnetic permeable portion 300 has a pole shoe via 310 for the electron beam to pass through, and a magnetic permeability weakening structure 320 is provided around the pole shoe via 310. This magnetic permeability weakening structure 320 introduces a high magnetic resistance region beside the pole shoe via 310, forcing the transverse magnetic field lines perpendicular to the first direction, which would normally cause electron beam deflection, to bend and shun, thereby weakening the transverse magnetic field component within the pole shoe via 310 region. This reduces the additional Lorentz force (Lorentz force generated by the transverse magnetic field component) experienced by the electron beam deviating from the central axis when traversing the pole shoe region, suppressing electron beam trajectory deflection and divergence, and thus improving the throughput of parallel multi-electron beam transmission in multi-electron beam vacuum electronic devices.

[0067] In one embodiment, such as Figure 1 As shown, the first permanent magnet 110 and the second permanent magnet 120 are cuboids. Both the first permanent magnet 110 and the second permanent magnet 120 have a first side and a second side that are spaced apart and opposite to each other along a second direction. The first side of the first permanent magnet 110 and the second side of the second permanent magnet 120 are facing each other and parallel to each other, so as to define a magnetic field space 500 between the first side of the first permanent magnet 110 and the second side of the second permanent magnet 120. The second direction is perpendicular to the first direction.

[0068] Specifically, designing the first permanent magnet 110 and the second permanent magnet 120 as cuboids offers advantages such as simple manufacturing, ease of processing and forming, high dimensional accuracy, and convenient assembly and positioning. Compared to other irregular shapes or permanent magnets such as circles and ellipses, cuboid permanent magnets can more easily achieve precise magnetic field distribution control and are beneficial for compact layout within a limited space.

[0069] Both the first permanent magnet 110 and the second permanent magnet 120 have a first side and a second side that are spaced apart and opposite to each other along a second direction. For a cuboid permanent magnet, its side surface generally refers to a plane perpendicular to a principal axis. Here, the first side and the second side that are spaced apart and opposite to each other along the second direction refer to two opposing surfaces of the cuboid permanent magnet in the second direction. The first side surface of the first permanent magnet 110 and the second side surface of the second permanent magnet 120 are arranged facing each other and parallel to each other, so as to define a magnetic field space 500 between the first side surface of the first permanent magnet 110 and the second side surface of the second permanent magnet 120. This arrangement ensures that a magnetic field space 500 with a well-defined boundary and a relatively uniform magnetic field distribution is formed between the two cuboid permanent magnets. Optionally, by making specific sides of the two permanent magnets parallel and opposite to each other, the direction and density of magnetic field lines can be effectively controlled, thereby generating the desired focused magnetic field within the magnetic field space 500. This parallel and opposite arrangement makes the magnetic field distribution within the magnetic field space 500 more predictable and stable.

[0070] The second direction is perpendicular to the first direction. The first direction is the extension direction of the first channel through which the electron beam passes, and is the axis of the multi-electron-beam vacuum electronic device. The second direction is the direction in which the first permanent magnet 110 and the second permanent magnet 120 are spaced apart. The fact that the second direction is perpendicular to the first direction means that the permanent magnet assembly 100 applies a magnetic field to the electron beam perpendicular to the electron beam transmission direction.

[0071] In one embodiment, such as Figure 3 As shown, each magnetic permeation section 300 has two pole shoe through holes 310, which are arranged at intervals along the second direction; each magnetic permeation section 300 has at least two magnetic permeation weakening structures 320, wherein at least one magnetic permeation weakening structure 320 is correspondingly disposed with one of the two pole shoe through holes 310, and at least one magnetic permeation weakening structure 320 is correspondingly disposed with the other of the two pole shoe through holes 310.

[0072] In one embodiment, the magnetic permeability weakening structure 320 is a through hole formed on the magnetic permeability portion 300; or, the magnetic permeability weakening structure 320 is a non-magnetic material filled in the through hole formed on the magnetic permeability portion 300.

[0073] The through hole is a hole that completely penetrates the magnetic permeable part 300 along the first direction (i.e., the direction of electron beam transmission), which can provide the maximum magnetic resistance over the entire axial length of the region, thereby producing a magnetic shunting effect.

[0074] The non-magnetic materials include, but are not limited to, oxygen-free copper, aluminum, austenitic stainless steel, or ceramic materials, which have low relative permeability close to that of a vacuum. Thus, while maintaining the high magnetoresistance characteristics of the permeability-reducing structure 320 (i.e., maintaining its function of changing the magnetic circuit direction and weakening the transverse magnetic field), the filler material serves as a structural support, preventing mechanical deformation or processing collapse caused by excessively thin partition walls between the pole shoe through-hole 310 and the permeability-reducing structure 320.

[0075] Since the magnetic permeability weakening structure 320 is only set in a local area of ​​the pole shoe and does not change the magnetization mode and main magnetic circuit configuration of the permanent magnet assembly 100, the magnetic field in the pole shoe through hole 310 area is still dominated by the axial magnetic field component before and after the introduction of the magnetic permeability weakening structure 320, and its overall magnetic field distribution remains basically unchanged.

[0076] In one embodiment, such as Figure 3 As shown, the cross-sectional shape of the magnetic permeability weakening structure 320 is one of a strip, an ellipse, or a circle.

[0077] It is understood that the cross-sectional shape of the via is one of a strip, an ellipse, or a circle. Alternatively, if the magnetic permeability weakening structure 320 is made of a non-magnetic material, the non-magnetic material is one of a strip, an ellipse, or a circle. Of course, in other embodiments, the specific selection of the magnetic permeability weakening structure 320 can also be other shapes, which are not limited here.

[0078] In one embodiment, such as Figure 1 As shown, the two pole shoe through holes 310 on the magnetic permeability part 300 of the first pole shoe 210 and the two pole shoe through holes 310 on the magnetic permeability part 300 of the second pole shoe 220 are aligned one by one along the first direction; at least two magnetic permeability weakening structures 320 on the magnetic permeability part 300 of the first pole shoe 210 and at least two magnetic permeability weakening structures 320 on the magnetic permeability part 300 of the second pole shoe 220 are aligned one by one along the first direction.

[0079] The phrase "the two pole shoe through holes 310 on the magnetic permeable part 300 of the first pole shoe 210 and the two pole shoe through holes 310 on the magnetic permeable part 300 of the second pole shoe 220 are one-to-one corresponding and coaxially arranged along the first direction" means that in the uniform permanent magnet focusing system 10, the two pole shoe through holes 310 respectively opened in the magnetic permeable parts 300 of the first pole shoe 210 and the second pole shoe 220 for the electron beam to pass through are precisely aligned in space. This alignment ensures that when the electron beam passes through the entire focusing system along the first direction (i.e., the transmission axis of the electron beam), it can smoothly and unobstructedly pass through one pole shoe through hole 310 on the magnetic permeable part 300 of the first pole shoe 210, enter the magnetic field space 500, and then pass through the corresponding other pole shoe through hole 310 on the magnetic permeable part 300 of the second pole shoe 220. This precise axial coaxial alignment is crucial for maintaining the transmission trajectory of the electron beam, avoiding electron beam deflection, collision, or distortion caused by misalignment of the pole shoe through holes 310. Achieving this alignment typically requires high-precision machining processes, such as CNC machining, as well as positioning using precision fixtures during assembly, or calibration through methods such as optical measurement and magnetic field mapping.

[0080] The phrase "at least two magnetic permeability weakening structures 320 on the magnetic permeability portion 300 of the first pole shoe 210 and at least two magnetic permeability weakening structures 320 on the magnetic permeability portion 300 of the second pole shoe 220 are one-to-one corresponding and coaxially arranged along the first direction" means that the magnetic permeability weakening structures 320 adjacent to the pole shoe through-hole 310 also maintain precise axial alignment between the first pole shoe 210 and the second pole shoe 220. The function of the magnetic permeability weakening structures 320 is to weaken the magnetic field component perpendicular to the first direction within the pole shoe through-hole 310, thereby optimizing the magnetic field distribution and making it closer to an ideal axially uniform field. When these magnetic permeability weakening structures 320 are coaxially arranged along the first direction, it means that the magnetic field weakening effect experienced by the electron beam at the first pole shoe 210 and the second pole shoe 220 as it passes through the entire focusing system is spatially continuous and symmetrical. This helps to form a more uniform and ideal axial magnetic field distribution, reducing the interference of the transverse magnetic field component perpendicular to the first direction on the electron beam, thereby improving focusing accuracy and stability. Achieving this alignment also relies on high-precision manufacturing and assembly techniques to ensure the precise axial alignment of these magnetically weakened structures 320.

[0081] In summary, this application ensures that the magnetic field environment experienced by the electron beam as it passes through the entire uniform permanent magnet focusing system 10 is highly continuous, symmetrical, and uniform.

[0082] In an optional embodiment, each magnetic permeability section 300 has two pole shoe through holes 310 and two magnetic permeability weakening structures 320 (specifically, magnetic weakening through holes). Each magnetic weakening through hole is located on the side of its corresponding pole shoe through hole 310 opposite to the other pole shoe through hole 310 (i.e., the two pole shoe through holes 310 are located on the inner side, and the two magnetic weakening through holes are located on the outermost side); and the major axes of the two pole shoe through holes 310 and the two magnetic weakening through holes extend radially along the main through hole 400 and are arranged parallel to each other.

[0083] In one embodiment, such as Figure 3 As shown, both the pole shoe via 310 and the magnetic permeability weakening structure 320 are elongated strips. The length of the magnetic permeability weakening structure 320 is greater than the length of the pole shoe via 310, and / or the width of the magnetic permeability weakening structure 320 is greater than the width of the pole shoe via 310.

[0084] Designing both the pole shoe via 310 and the magnetic weakening via as elongated vias means that the cross-sectional shape of these vias has one dimension significantly longer than the other, such as a rectangle. This elongated design allows for more precise control over the area and direction of magnetic field weakening, enabling targeted adjustments to the magnetic field distribution to suit different focusing requirements. Compared to circular or other symmetrical vias, the elongated pole shoe via 310 and magnetic weakening via provide an asymmetric magnetoresistance distribution in a specific direction, which helps to form a more uniform or specific gradient magnetic field that better conforms to the characteristics of multi-electron beam alignment.

[0085] Furthermore, the length of the magnetically weakening through-hole is greater than the length of the pole shoe through-hole 310, and / or the width of the magnetically weakening through-hole is greater than the width of the pole shoe through-hole 310. This means that the magnetically weakening through-hole is larger than the pole shoe through-hole 310 in at least one dimension (length or width, or both). When the length or width of the magnetically weakening through-hole increases, the volume of the high-permeability material occupied by it in the magnetic permeability portion 300 decreases accordingly, thereby increasing the magnetic reluctance of the region more significantly over a larger area. This dimensional difference design allows the magnetically weakening through-hole to more effectively weaken the magnetic field component perpendicular to the first direction within the pole shoe through-hole 310. By adjusting the size of the magnetically weakening through-hole relative to the pole shoe through-hole 310, the degree and range of magnetic field weakening can be precisely controlled to achieve optimal magnetic field uniformity. For example, if magnetic field weakening is required over a longer region, the length of the magnetically weakening through-hole can be increased; if the degree of transverse magnetic field weakening is required to be increased, the width of the magnetic permeability weakening structure can be increased. This flexible dimensional design provides greater freedom for magnetic field control.

[0086] Understandably, the specific configuration parameters of the magnetic permeability weakening structure 320 can be highly customized according to the actual physical requirements of multi-electron-beam vacuum electronic devices. First, the number of electron beams directly determines the configuration base of the magnetic permeability weakening structure 320, usually adopting a one-to-one or grouped distribution strategy to ensure that each electron beam has a corresponding magnetic field correction mechanism around it. Second, the offset of the electron beam relative to the central axis of the magnetic field is a key factor in determining the correction strength. Since the transverse magnetic field component of the uniform permanent magnet focusing system 10 usually increases with the radial distance, for electron beams with a large offset (i.e., far from the central axis), it is necessary to design a larger magnetic permeability weakening structure 320 (e.g., longer in length or wider in width), or adjust its distribution position to be closer to the edge of the pole shoe via 310 to generate a stronger magnetic shunting effect to counteract the strong transverse distortion field at that location. Finally, the size of the electron beam channel limits the physical spatial range of the magnetic field effect, and the geometric span of the magnetic permeability weakening structure 320 must match it to cover the effective cross-section through which the electron beam passes. By comprehensively adjusting the above parameters, the focusing system of this application can flexibly adapt to various complex electron beam arrangements, including single-column linear arrays, double-column side-by-side arrays, or multi-column matrices, ensuring that each electron beam in different spatial positions in the array can obtain a highly consistent and stable focusing effect.

[0087] In one embodiment, such as Figure 1 As shown, the magnetic permeable portion 300 in the main through hole 400 of the first pole shoe 210 is integrally disposed with the first pole shoe 210; and the magnetic permeable portion 300 in the main through hole 400 of the second pole shoe 220 is integrally disposed with the second pole shoe 220.

[0088] The magnetic permeable portion 300 within the main through-hole 400 of the first pole shoe 210 is integrally formed with the first pole shoe 210. This integral forming process, such as integral casting, forging, sintering, additive manufacturing, or precision machining methods like wire cutting, allows the magnetic permeable portion 300 and the first pole shoe 210 to be continuous in the magnetically conductive material and seamlessly connected in structure. This integrally formed structure eliminates the physical and magnetic circuit connection interfaces between components, avoiding sudden changes in magnetic reluctance and performance degradation caused by loose connectors, assembly gaps, deformation, or material mismatch.

[0089] Optionally, the magnetic permeable part 300 can be a block, sheet, column, or ring structure. The outer contour shape of the magnetic permeable part 300 matches the inner wall shape of the main through hole 400, so as to be tightly embedded in the main through hole 400 or integrally formed therewith.

[0090] In one embodiment, such as Figure 1As shown, the cross-section of the main through hole 400 of the first pole shoe 210 and the second pole shoe 220 is circular, and the cross-section of the magnetic permeable part 300 is circular; the magnetic permeable part 300 in the first pole shoe 210 faces the surface of the magnetic field space 500 and is flush with the surface of the first pole shoe 210 facing the magnetic field space 500; the magnetic permeable part 300 in the second pole shoe 220 faces the surface of the magnetic field space 500 and is flush with the surface of the second pole shoe 220 facing the magnetic field space 500.

[0091] Specifically, a circular cross-section has significant advantages for electron beam transmission. It ensures that the electron beam is subjected to an axisymmetric radial magnetic field when passing through the channel, thereby avoiding astigmatism caused by an asymmetric magnetic field and guaranteeing the focusing quality and transmission flow rate of the electron beam.

[0092] In this design, the magnetic permeable portion 300 inside the first pole piece 210 is flush with the surface of the first pole piece 210 facing the magnetic field space 500. When the electron beam enters the magnetic field space 500 from the main through-hole 400, if there is a height difference (i.e., a step) between the surface of the magnetic permeable portion 300 and the surface of the pole piece, a sudden change in the magnetic field or a local magnetic field gradient will occur at the interface, causing the electron beam to be subjected to additional non-uniform forces, thus affecting its trajectory. By flushing the surface, the flatness of the magnetic field boundary conditions can be maintained to the maximum extent, reducing magnetic field discontinuities and ensuring that the magnetic field lines transition smoothly from the pole piece to the magnetic field space 500. Similarly, this application also adopts a flush design between the magnetic permeable portion 300 inside the second pole piece 220 and the surface of the second pole piece 220 facing the magnetic field space 500. This symmetrical flush design also plays a crucial role when the electron beam leaves the magnetic field space 500. It ensures that the magnetic field environment remains stable when the electron beam leaves the main focusing magnetic field region, avoiding unnecessary magnetic field disturbances at the exit end.

[0093] In one feasible embodiment, the uniform permanent magnet focusing system 10 includes a first permanent magnet 110 and a second permanent magnet 120 spaced apart along a second direction, and a pole piece assembly 200 (including a first pole piece 210 and a second pole piece 220) respectively disposed at and connected to both ends (i.e., the first end and the second end) of the permanent magnet assembly 100. The magnetization directions of the first permanent magnet 110 and the second permanent magnet 120 are both arranged along the first direction and are in the same direction. Together with the pole piece assembly 200, they form a closed magnetic circuit system. With the electron beam transmission direction as the axis (i.e., the first direction), the closed magnetic circuit forms an approximately uniform focusing magnetic field in the magnetic field space 500, with the magnetic field component in the first direction being dominant and the transverse magnetic field component perpendicular to the first direction being smaller. This is used to effectively constrain the transverse divergence of the electron beam during its transmission along the first path. Magnetic permeable portions 300 are provided within the main through-holes 400 of the first pole shoe 210 and the second pole shoe 220. Each magnetic permeable portion 300 has two pole shoe through-holes 310 spaced apart along the second direction, each allowing electron beams to pass through. The pole shoe through-holes 310 penetrate the magnetic permeable portion 300 along the first direction, and have a cross-sectional dimension of 12mm × 1mm. Because the two pole shoe through-holes 310 are located at different heights in the second direction (i.e., offset relative to the central axis of the magnetic field space 500), their relative spatial positions with the first permanent magnet 110 or the second permanent magnet 120 differ, causing local changes in the magnetic flux distribution near the pole shoe through-holes 310. On the side of the magnetic permeable portion 300 near the permanent magnet assembly 100, some magnetic lines of force will be deflected, thereby introducing a certain transverse magnetic field component perpendicular to the first direction into the region of the pole shoe through-holes 310. For electron beams deviating from the central axis of the uniform permanent magnet focusing system 10, the transverse magnetic field component will generate a transverse Lorentz force, which can easily cause electron beam trajectory deflection, becoming a local problem that needs to be suppressed during the stable focusing and efficient transmission of multiple electron beams. To solve the above problem, without changing the magnetization method and overall magnetic circuit configuration of the permanent magnet assembly 100, this embodiment introduces a magnetic permeability weakening structure 320 in a local area of ​​the magnetic permeability section 300 to finely control the magnetic flux distribution near the pole shoe through-hole 310. The magnetic permeability weakening structure 320 is preferably an elongated magnetic weakening through-hole disposed on the magnetic permeability section 300, but other configurations with equivalent magnetic permeability weakening effects can also be used. The magnetic weakening through-hole extends along the first direction and has a size of 13mm × 1.7mm. This structure is disposed in the peripheral adjacent region of the pole shoe through-hole 310 and on the side of the pole shoe through-hole 310 away from the other pole shoe through-hole 310 (i.e., closer to the corresponding permanent magnet). By locally reducing the equivalent permeability of the magnetic permeability portion 300 in this region, it forces part of the magnetic flux to bypass the region near the pole shoe through-hole 310, thereby weakening the transverse magnetic field component perpendicular to the first direction within the pole shoe through-hole 310. The magnetic permeability weakening structure 320 can be a through-hole that remains as a cavity, or it can be a composite structure filled with non-magnetic material.

[0094] The following simulation verification is given:

[0095] It should be noted that, in Figures 4 to 6 The changes in the two electron beams before and after the introduction of the magnetic permeability weakening structure 320 are shown. These two electron beams will be referred to as electron beam 1 and electron beam 2. The center coordinates of electron beam 1 are (0.7 mm, 1.5 mm), and the center coordinates of electron beam 2 are (…). 0.7mm, 1.5mm).

[0096] like Figure 4 As shown, the axial magnetic field Bz at the center positions of electron beams 1 and 2 along the first direction (i.e., the electron beam propagation direction, corresponding to the z-axis in the figure) is shown before and after the introduction of the magnetic permeability weakening structure 320. Figure 4 The horizontal axis represents the transmission distance z (in mm) along the first direction, and the vertical axis represents the magnitude of the axial magnetic field Bz (in T). The center coordinates of electron beam 1 and electron beam 2 are (0.7 mm, 1.5 mm) and ( (0.7mm, 1.5mm). Simulation results show that at the above locations, the distribution curves of the axial magnetic field Bz before and after the introduction of the magnetic permeability weakening structure 320 are almost completely coincident, indicating that the structure will not destroy the main axial focusing magnetic field.

[0097] like Figure 5 , Figure 6 As shown, the variations of the transverse magnetic field components Bx and By along the first direction (z-axis) at the center positions of electron beam 1 and electron beam 2 before and after the introduction of the magnetic permeability weakening structure 320 are presented. Among them, Figure 5 and Figure 6 The horizontal axis represents the transmission distance z (in mm) along the first direction, and the vertical axis represents the magnitudes (in Gauss) of the transverse magnetic field components Bx and By, respectively. Since electron beam 1 and electron beam 2 are symmetrical about the central axis at x=0 and are both located in the y>0 region, their Bx components have equal amplitudes but opposite directions, while their By components have the same direction and consistent amplitude. Simulation results show that in the region near the pole shoe via, before the introduction of the magnetic permeability weakening structure, the dominant transverse magnetic field is the By component (e.g., ...). Figure 6 As shown, its peak value is close to 80 Gauss, while the Bx component is extremely small (as shown). Figure 5As shown, the peak value is only about 2.5 Gauss. After introducing the magnetic permeability weakening structure, the peak amplitude of the dominant By component drops sharply and is suppressed to about 10 Gauss. At the same time, although the amplitude of the Bx component increases slightly (the peak value is about 5 Gauss), its absolute value is still extremely small and has a negligible impact on the overall electron beam trajectory. It can be seen that this application achieves effective suppression of the transverse deflection force on the electron beam by significantly weakening the most important transverse magnetic field component (By component) without affecting the axial magnetic field Bz.

[0098] Under the aforementioned magnetic field conditions, particle trajectory simulation analysis was performed on a 2×2 four-channel electron beam system. Simulation results show that, as Figure 7 In the current comparison results shown (where the horizontal axis represents the transmission distance z along the first direction, in mm; the vertical axis represents the current of a single electron beam, in A, with negative values ​​indicating the direction of electron flow), for the traditional magnetic focusing system without the introduction of the magnetic permeability weakening structure 320, the electron beam is severely deflected and completely intercepted by the channel wall after transmitting about 5 mm, with the flux dropping to 0, and the electron beam cannot achieve effective transmission; however, after introducing the magnetic permeability weakening structure 320, the four electron beams can maintain stable transmission throughout the entire magnetic field space of about 60 mm within the 500 region, and the electron beam flux remains stably maintained at the initial full load state (shown in the figure -0.6 A), that is, the transmission flux is improved.

[0099] Further analysis of the motion behavior of the electron beam during its passage through the pole shoe aperture 310 reveals that the introduction of the magnetic permeability weakening structure 320 significantly reduces the transverse magnetic field effect on the electron beam, significantly decreases its transverse deflection, and significantly reduces the phenomenon of the electron beam being intercepted by the channel wall, thereby effectively improving the focusing and transmission flow rate of the multi-electron beam system.

[0100] like Figure 8 As shown, the distribution comparison results of the electron beam in the xy cross section perpendicular to the first direction are presented at z=5.3mm (i.e., the sensitive region near the pole shoe via 310). Figure 8 The x and y coordinates represent the radial geometric positions within the cross-section (unit: mm), and the solid rectangular boxes in the figure represent the channel walls for electron beam transmission. It can be seen that after introducing the magnetic permeability weakening structure 320 (such as...), Figure 8 As shown on the left), the cross-sectional shape of the electron beam remained well-preserved, all centered within the channel, without significant deformation or displacement; while under traditional structural conditions (such as... Figure 8 As shown on the right), the electron beam undergoes significant deformation and deflection, with its edges already touching or even being intercepted by the channel wall.

[0101] In addition, such as Figure 9As shown, the electron trajectory distribution of two symmetrical electron beams (electron beam 1 and electron beam 2) in the xz and yz planes is illustrated under magnetic focusing conditions after the introduction of the magnetic permeability weakening structure 320. The horizontal axis represents the transmission distance z (in mm) along the first direction, and the vertical axis represents the position coordinates (in mm) in the radial x and y directions, respectively. The horizontal dashed line represents the physical boundary of the channel wall. It can be seen that the electron beams can achieve stable transmission within a transmission distance of approximately 60 mm. The electron wave trajectory is effectively constrained within the channel wall range, the overall trajectory is smooth, there is no obvious lateral deflection or defocusing, and no channel wall interception occurs throughout the entire process.

[0102] This application also provides a multi-electron-beam vacuum electronic device, which includes a main body, an electron gun, and a uniform permanent magnet focusing system 10. The main body has a first channel through which the electron beam passes and extends along a first direction; the electron gun is disposed on the main body for emitting the electron beam; the uniform permanent magnet focusing system 10 is disposed on the main body and positioned corresponding to the first channel for magnetically focusing the electron beam transmitted along the first channel.

[0103] It should be noted that the multi-electron-beam vacuum electronic device includes the uniform permanent magnet focusing system 10 in the above embodiments. Therefore, the multi-electron-beam vacuum electronic device can at least achieve all the beneficial effects brought by the uniform permanent magnet focusing system 10 in the above embodiments, which will not be described in detail here.

[0104] The main body is the core structure of the multi-electron-beam vacuum electronic device. Its main function is to provide a stable vacuum environment and serve as a supporting framework for all internal components. Inside the main body, there is a first channel extending along a first direction through which the electron beam passes. The geometry and dimensions of this first channel are carefully designed to ensure smooth passage of the electron beam while minimizing interaction with the channel walls.

[0105] The electron gun is a key component in multi-electron-beam vacuum electronic devices used to generate and accelerate electron beams. An electron gun typically includes a cathode for emitting electrons; one or more grids for controlling the amount of electrons emitted; and one or more anodes for accelerating the electrons to form an electron beam with specific energy and direction. The electron gun is precisely mounted inside the main body, and the emitted electron beam can accurately enter the first channel.

[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no technical conflict, the various technical features mentioned in the various embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A uniform permanent magnet focusing system, characterized in that, A uniform permanent magnet focusing system is applied to a multi-electron-beam vacuum electronic device, wherein the multi-electron-beam vacuum electronic device has a first channel through which an electron beam passes and extends along a first direction, and the uniform permanent magnet focusing system includes: A permanent magnet assembly is used to be disposed in the multi-electron-beam vacuum electronic device, including a first permanent magnet and a second permanent magnet. The first permanent magnet and the second permanent magnet are spaced apart along a second direction to form a magnetic field space between the first permanent magnet and the second permanent magnet. The first permanent magnet and the second permanent magnet have the same magnetization direction along the first direction. The pole shoe assembly includes a first pole shoe and a second pole shoe. The first permanent magnet and the second permanent magnet each have a first end and a second end disposed opposite to each other along a first direction. The first pole shoe is disposed at the first end of the first permanent magnet and the second permanent magnet, and the second pole shoe is disposed at the second end of the first permanent magnet and the second permanent magnet. The first pole shoe and the second pole shoe each have a main through hole extending along the first direction and communicating with the magnetic field space. The main through hole of the first pole shoe, the magnetic field space, and the main through hole of the second pole shoe are distributed in the first channel. Each of the two main through holes has a magnetic permeable portion near one end of the permanent magnet assembly. The magnetic permeable portion has a pole shoe through hole and a magnetic permeability weakening structure. The pole shoe through hole extends through the magnetic permeable portion along a first direction and extends radially along the main through hole. The magnetic permeability weakening structure is located on one side of the pole shoe through hole and is used to weaken the magnetic field component perpendicular to the first direction in the pole shoe through hole.

2. The uniform permanent magnet focusing system as described in claim 1, characterized in that, The first permanent magnet and the second permanent magnet are cuboids, and both the first permanent magnet and the second permanent magnet have a first side surface and a second side surface that are spaced apart and opposite to each other along the second direction; The first side of the first permanent magnet and the second side of the second permanent magnet are arranged facing each other and parallel to each other, so as to define the magnetic field space between the first side of the first permanent magnet and the second side of the second permanent magnet; wherein the second direction is perpendicular to the first direction.

3. The uniform permanent magnet focusing system as described in claim 1, characterized in that, Each of the magnetic permeable parts has two pole shoe through holes, and the two pole shoe through holes are arranged at intervals along the second direction; Each of the magnetic permeable parts has at least two magnetic permeability weakening structures, wherein at least one of the magnetic permeability weakening structures is disposed corresponding to one of the two pole shoe through holes, and at least one of the magnetic permeability weakening structures is disposed corresponding to the other of the two pole shoe through holes.

4. The uniform permanent magnet focusing system as described in claim 3, characterized in that, The magnetic permeability weakening structure is a through hole formed on the magnetic permeability part; or, the magnetic permeability weakening structure is a non-magnetic material filled in the through hole formed on the magnetic permeability part.

5. The uniform permanent magnet focusing system as described in claim 4, characterized in that, The cross-sectional shape of the magnetic permeability weakening structure is one of the following: elongated, elliptical, or circular.

6. The uniform permanent magnet focusing system as described in claim 3, characterized in that, The two pole shoe through holes on the magnetic permeable part of the first pole shoe and the two pole shoe through holes on the magnetic permeable part of the second pole shoe are aligned one by one along the first direction; At least two magnetic permeability weakening structures on the magnetic permeability portion of the first pole shoe and at least two magnetic permeability weakening structures on the magnetic permeability portion of the second pole shoe are aligned one-to-one along the first direction.

7. The uniform permanent magnet focusing system as described in claim 6, characterized in that, Both the pole shoe via and the magnetic permeability weakening structure are elongated, with the length of the magnetic permeability weakening structure being greater than the length of the pole shoe via, and / or the width of the magnetic permeability weakening structure being greater than the width of the pole shoe via.

8. The uniform permanent magnet focusing system as described in claim 1, characterized in that, The magnetic permeable portion within the main through-hole of the first pole shoe is integrally formed with the first pole shoe; and... The magnetic permeable portion inside the main through hole of the second pole shoe is integrally formed with the second pole shoe.

9. The uniform permanent magnet focusing system according to any one of claims 1 to 8, characterized in that, The cross-section of the main through hole of the first and second pole shoes is circular, and the cross-section of the magnetic permeable part is circular; The magnetic permeable portion inside the first pole shoe faces the surface of the magnetic field space and is flush with the surface of the first pole shoe facing the magnetic field space. The magnetic permeable portion inside the second pole shoe faces the surface of the magnetic field space and is flush with the surface of the second pole shoe facing the magnetic field space.

10. A multi-electron-beam vacuum electronic device, characterized in that, The multi-electron-beam vacuum electronic device includes: The main body has a first channel through which electrons are injected and which extends in a first direction; An electron gun, disposed on the main body, is used to emit the electron beam; and The uniform permanent magnet focusing system as described in any one of claims 1 to 9, wherein the uniform permanent magnet focusing system is disposed on the main body and the position corresponds to the first channel, for magnetic focusing of the electron beam transmitted along the first channel.

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