An electron gun comprising segmented insulating ceramic

Abstract

The application relates to an electron gun containing segmented insulating ceramics, which comprises an anode, segmented insulating ceramics, a cathode support, a cathode cylinder, a cathode and a focusing electrode, the segmented insulating ceramics comprises a plurality of ceramic segments, a suspended electrode is arranged between adjacent ceramic segments, the suspended electrode and the ceramic segments are alternately stacked, the upper-to-lower direction is along the direction in which the anode points to the cathode support, the inner-to-outer direction is along the direction in which the cathode cylinder points to the segmented insulating ceramics, a shielding ring is arranged on the lower end surface of the anode and the inner side of each suspended electrode, and an anti-corona ring is arranged on the outer side of each suspended electrode. Compared with the prior art, the segmented insulating ceramic structure containing ceramic segments with different lengths and the shielding ring with the function of shielding the cathode cylinder to emit electron bombardment on the ceramics are designed, the uniformity of the electric field on the ceramic surface of the electron gun is improved, the peak electric field strength on the ceramic surface is reduced, the insulation capacity of the electron gun shell is improved, and the application has the advantage of high insulation capacity.

Description

Technical Field

[0001] The invention belongs to the field of vacuum electronics technology, relates to a solution to the problem of surface insulation of a magnetic ring of an electron gun, and in particular to an electron gun comprising segmented insulating ceramics. Background Art

[0002] Vacuum electronic devices such as klystrons and traveling wave tubes (TWTs) utilize the interaction of electrons with electromagnetic waves in the specialized vacuum environment to achieve energy conversion, and are widely used in high-power, high-frequency applications. The electron gun in a vacuum electronic device generates an electron beam of a specific shape and energy. Voltages between the cathode and anode typically range from several thousand to several hundred kilovolts. The ceramic ring is a ring-shaped ceramic structure within the electron gun housing, located between the cathode support and the anode (the cathode support is connected to the cathode via a cathode tube and has the same potential as the cathode), providing support and insulation. Surface flashover is a corona discharge phenomenon that forms on the surface of the magnetic ring. Surface flashover indicates insulation failure in the vacuum electronic device, jeopardizing proper operation and, in severe cases, even directly damaging the magnetic ring. The voltage required for surface flashover in the magnetic ring is much lower than the voltage required to break down a vacuum gap of the same size or to break down the ceramic body. Therefore, surface flashover is a significant factor limiting the insulation strength of the electron gun housing. As vacuum electronic devices advance toward higher power and smaller sizes, the electric field strength within the electron gun continues to increase, making surface flashover on the insulating ceramic surface more susceptible to such conditions, a crucial consideration during design. .

[0003] Conventional electron guns utilize a single, long ceramic ring. Excessive field strength and electron bombardment are generally considered the primary triggers for surface flashovers on insulating ceramics. To overcome this issue, previous studies have typically employed anti-corona rings to reduce the field strength at the intersection of the ceramic, vacuum, and metal. However, this still presents challenges, such as uneven field distribution on the ceramic surface, resulting in high peak field strengths. Furthermore, the rings are unable to shield the ceramic surface from high-energy electrons emitted from the cathode tube, limiting their insulation capabilities. Summary of the Invention

[0004] An object of the present invention is to provide an electron gun comprising segmented insulating ceramics capable of improving the insulation capability of the electron gun.

[0005] The purpose of the present invention can be achieved by the following technical solutions:

[0006] An electron gun including segmented insulating ceramics includes an anode, segmented insulating ceramics, a cathode support, a cathode tube, a cathode, and a focusing electrode. The anode, segmented insulating ceramics, and cathode support are sequentially connected to form a gun shell of the electron gun, realizing the function of a vacuum sealed chamber. The cathode tube, cathode, and focusing electrode are located in the vacuum sealed chamber. The cathode tube is mounted on the cathode support, and the cathode and focusing electrode are mounted on the cathode tube.

[0007] The segmented insulating ceramic comprises a plurality of ceramic segments, and a suspension electrode is arranged between adjacent ceramic segments, and the suspension electrode and the ceramic segment are alternately stacked,

[0008] In a direction from the anode to the cathode support, an upper-to-lower direction, and in a direction from the cathode cylinder to the segmented insulating ceramic, an inner-to-outer direction, a lower end surface of the anode and an inner side of each of the suspension electrodes are provided with a shielding ring, and an outer side of each of the suspension electrodes is provided with a corona-preventing ring.

[0009] Further, a pressure in the vacuum sealed cavity is less than or equal to 10 -5 Pa.

[0010] Further, an axial length of each of the ceramic segments is non-uniform, so that the suspension electrodes are arranged at non-uniform intervals.

[0011] Further, in the direction from the anode to the cathode support, an axial length of a first ceramic segment is the longest, an axial length of a second ceramic segment is the second longest, and axial lengths of the remaining ceramic segments are shorter.

[0012] Further, the axial lengths of the remaining ceramic segments are the same.

[0013] Further, a thickness of the shielding ring near the anode is smaller than a thickness of the shielding ring away from the anode, and the thinner part is closer to the ceramic segment.

[0014] Further, among the shielding rings connected to the suspension electrodes, an upper end surface of the shielding ring near the anode is higher than an upper end surface of the suspension electrode connected thereto.

[0015] Further, all the corners of each of the shielding rings are rounded.

[0016] Further, there is a gap between the corona-preventing ring and the segmented insulating ceramic.

[0017] Further, an end of the corona-preventing ring is in a smooth arc structure.

[0018] Compared with the prior art, the present application has the following beneficial effects:

[0019] 1. By optimizing the shell structure of the electron gun, the present application designs the segmented insulating ceramic separated by the suspension electrode, and designs the shielding ring structure on the suspension electrode, thereby improving the uniformity of the electric field on the surface of the electron gun ceramic, reducing the peak electric field strength on the surface of the ceramic, solving the problem that the electric field is concentrated in the traditional shielding ring design, causing the ceramic to easily flash along the surface, effectively improving the insulation capacity, and having the advantages of strong insulation capacity, etc., which is of great significance to increase the power capacity and reliability of the microwave device.

[0020] 2、The length of each ceramic segment of the segmented insulating ceramic is not the same. Since the potential difference between the focusing electrode outside the cathode and the cathode is not large, and the distance between the focusing electrode and the anode is usually small, the position of the strongest electric field in the electron gun is usually between the focusing electrode and the anode. The two segments near the anode of the segmented insulating ceramic are longer, and the corresponding shield ring is also longer. Due to the influence of the focusing electrode and the anode, the electric field near the shield ring near the anode is stronger than that of the shield ring far from the anode, and under the condition that the distance between the shield rings is not different, this will cause the potential difference between the shield rings closer to the anode to be larger. The potential difference between the upper and lower ends of the magnetic ring is the same as the potential difference between the shield rings connected to the upper and lower ends of the magnetic ring, so the potential difference between the upper and lower ends of the magnetic ring near the anode is higher. Under this condition, if the length of each magnetic ring is the same, the electric field on the surface of the magnetic ring near the anode will be stronger. The present application increases the length of the magnetic ring near the anode, which can reduce the electric field strength on the surface of the corresponding magnetic ring, thereby forming a more uniform electric field distribution on the surface of the entire segmented insulating ceramic and reducing the peak electric field.

[0021] 3、The main function of the shield ring designed in the present application is to shield the high-energy electron emitted by the cathode cylinder from hitting the ceramic to avoid breakdown. Each corner of the shield ring is rounded to form a smooth arc surface, avoiding the concentration of electric field caused by sharp corners and preventing the electric field at the end of the shield ring from being too large.

[0022] 4、The corona shield ring of the present application is arranged outside the lower end of the anode and the upper end of the cathode support, and is used to reduce the electric field strength at the position of the three combination points of ceramic, vacuum and metal. In addition, the upper part of the corona shield ring is also located near the three combination points of ceramic, vacuum and metal, which also plays a role in reducing the electric field strength at the position of the three combination points. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a perspective view of the electron gun of the present application;

[0024] Figure 2 is an axial sectional view of the electron gun of the present application;

[0025] Figure 3 is an enlarged view of A in Figure 2 ; is an enlarged view of B in

[0026] Figure 4 is an enlarged view of B in Figure 2 ; is an enlarged view of B in

[0027] Figure 5 is a simulation diagram of the electric field strength on the inner surface of the insulating ceramic;

[0028] BRIEF DESCRIPTION OF DRAWINGS

[0029] 1. Electron gun; 2. Anode; 3. Segmented insulating ceramic; 31. Ceramic segment; 32. Suspended electrode; 33. Shielding ring; 331. First ring segment; 332. Second ring segment; 34. Anti-corona ring; 4. Cathode; 5. Cathode support; 6. Cathode tube; 7. Focusing electrode. DETAILED DESCRIPTION

[0030] With reference to the accompanying drawings, schematic diagrams of the electron gun disclosed in the present invention are described in detail. While the drawings are provided to illustrate some embodiments of the present invention, they are not necessarily drawn to the scale of the specific embodiments, and certain features may be enlarged, removed, or partially cut away to better illustrate and explain the disclosure. Some components in the drawings may be repositioned as needed without affecting the technical effect. The phrase "in the drawings" or similar terms appearing in this specification do not necessarily refer to all figures or examples.

[0031] Certain directional terms used in the following description of the drawings, such as "inner," "outer," "above," "below," and other directional terms, should be understood to have their normal meanings and refer to those directions when the drawings are normally viewed. Unless otherwise indicated, the directional terms used in this specification are generally in accordance with conventional directions understood by those skilled in the art.

[0032] The terms "first", "first", "second", "second" and similar terms used in the present invention do not indicate any order, quantity or importance, but are used to distinguish one component from other components.

[0033] like Figure 1 and Figure 2 As shown, this embodiment provides an electron gun 1 including segmented insulating ceramics, including an anode 2, a segmented insulating ceramic 3, a cathode support 5, a cathode tube 6, a cathode 4, and a focusing electrode 7. The anode 2, the segmented insulating ceramic 3, and the cathode support 5 are sequentially connected to form a vacuum sealed chamber for accommodating other components of the electron gun. The cathode tube 6, which has the cathode 4 and the focusing electrode 7 connected to its upper end, serves as the gun housing of the electron gun. The cathode tube 6 is mounted on the cathode support 5 and is located in the vacuum sealed chamber. The pressure in the vacuum sealed chamber is less than or equal to 10 -5 In this embodiment, the segmented insulating ceramic 3 is made of alumina ceramic.

[0034] In this embodiment, the direction from the anode 2 to the cathode support 5 is taken as the top-to-bottom direction, and the segmented insulating ceramic 3 has two upper and lower end faces. The anode 2 has a lower end face welded to the upper end face of the segmented insulating ceramic 3, and the cathode support 5 has an upper end face welded to the lower end face of the segmented insulating ceramic 3.

[0035] The segmented insulating ceramic 3 is in a cylindrical shape, and includes a plurality of ceramic segments 31, and a metal floating electrode 32 is arranged between adjacent ceramic segments 31. The floating electrode 32 and the ceramic segments 31 are alternately stacked, and the lengths of the ceramic segments are not completely the same, so that the uniformity of the electric field intensity on the surface of the insulating ceramic can be improved. Figure 5 A comparison of the electric field intensity on the surface of the ceramic in the case of the non-uniform segmented insulating ceramic, the uniform segmented insulating ceramic, the floating electrode without the shielding ring, and the shielding ring is shown. The non-uniform segmented insulating ceramic can improve the uniformity of the electric field intensity on the surface of the insulating ceramic.

[0036] In this embodiment, five non-uniform floating electrodes 32 are arranged, and each floating electrode has two end faces and two surfaces. The lengths of the ceramic segments in the axial direction are non-uniform, and the floating electrodes 32 are arranged at non-uniform intervals. In this embodiment, the length of the first ceramic segment in the axial direction is the longest, the length of the second ceramic segment is the second longest, and the lengths of the remaining ceramic segments are relatively short. In this embodiment, the lengths of the remaining ceramic segments are the same.

[0037] In this embodiment, the direction from the cathode cylinder to the segmented insulating ceramic is the inner-to-outer direction, the lower end face of the anode 2 and the inner side of each floating electrode 32 are provided with a shielding ring 33, the shielding ring 33 is designed to have a gradient structure and a rounded end, and the part close to the anode is thin and close to the ceramic, and the part far from the anode is thick and far from the ceramic. On the one hand, it is used to shield the high-energy electrons emitted by the cathode from bombarding the ceramic, and on the other hand, it is used to reduce the electric field intensity of the nearby three junctions. Figure 4 An enlarged view of the structure of the shielding ring according to this embodiment is shown. As shown in Figure 4 The shielding ring 33 includes a first ring section 331 and a second ring section 332 connected in the radial direction of the electron gun 1. The first ring section is thin and close to the ceramic segment 31, and the second ring section 332 is thick and far from the ceramic segment 31. The end of the shielding ring 33 is rounded to prevent stress concentration and high electric field intensity.

[0038] In this embodiment, the shielding ring 33 is provided with six shielding rings. The first shielding ring is welded to the lower end face of the anode 2, and the second to the sixth shielding rings are welded to the lower end faces of the floating electrodes 32, respectively. Among the shielding rings 33 connected to the floating electrodes 32, the upper end face of the shielding ring 33 close to the anode 2 is slightly higher than the upper end face of the floating electrode 32 connected thereto, which effectively increases the effect of the shielding ring.

[0039] As shown in Figure 2As shown, the embodiment is provided with 6 ceramic segments. The first shielding segment has the largest axial length, the axial length of the second shielding ring is smaller than the axial distance of the first shielding ring, the axial lengths of the third shielding ring to the sixth shielding ring are the same and are smaller than the axial lengths of the first shielding ring and the second shielding ring. Meanwhile, in order to avoid the field intensity being too high at the end of the first shielding ring and the second shielding ring, the distance between the first shielding ring, the second shielding ring and the inner surface of the segmented insulating ceramic 3 is increased.

[0040] Figure 3 An enlarged view of the structure of the anti-corona ring according to the embodiment is shown. The anti-corona ring 34 is welded to the outer surface of the suspension electrode 32, the outer side of the upper end surface of the cathode support 5 and the outer side of the lower end surface of the anode 2. There is a gap between the anti-corona ring 34 and the ceramic segment 31. The upper and lower end surfaces of the anti-corona ring 34 are treated with a circular arc to avoid the field intensity being too high at the end surfaces.

[0041] Figure 3 An enlarged view of the structure of the suspension electrode according to the embodiment is shown. The outer surface of the suspension electrode 32 is welded to the inner surface of the anti-corona ring 34. The inner surface of the suspension electrode 32 is welded to the shielding ring 33. The lower end of the upper shielding ring and the upper end of the lower shielding ring just coincide in the axial direction, thereby avoiding the phenomenon that the high-energy electrons emitted by the cathode cylinder 6 bombard the ceramic segment 31.

[0042] The electronic gun provided by the embodiment and containing the segmented insulating ceramic can effectively avoid the situation that the field intensity at the surface of the insulating ceramic and the three intersection points is high and can shield the bombardment of the electrons emitted by the cathode cylinder to the ceramic.

[0043] The above embodiments only illustrate the technical idea of the present application and cannot limit the protection scope of the present application. Any modification made on the basis of the technical idea of the present application and the technical scheme falls within the protection scope of the present application.

Claims

1. An electron gun comprising segmented insulating ceramics, characterized in that: The invention comprises an anode (2), a segmented insulating ceramic (3), a cathode support (5), a cathode cylinder (6), a cathode (4) and a focusing electrode (7); the anode (2), the segmented insulating ceramic (3) and the cathode support (5) are connected in sequence to form a gun shell of an electron gun, realizing the function of a vacuum sealed chamber; the cathode cylinder (6), the cathode (4) and the focusing electrode (7) are located in the vacuum sealed chamber; the cathode cylinder (6) is mounted on the cathode support (5); the cathode (4) and the focusing electrode (7) are mounted on the cathode cylinder (6); wherein, The segmented insulating ceramic (3) comprises a plurality of ceramic segments (31), wherein suspending electrodes (32) are provided between adjacent ceramic segments (31), and the suspending electrodes (32) and the ceramic segments (31) are alternately stacked. With the direction from the anode (2) pointing toward the cathode support (5) as the top-to-bottom direction, and the direction from the cathode tube (6) pointing toward the segmented insulating ceramic (3) as the inside-to-outside direction, a shielding ring (33) is provided on the lower end surface of the anode (2) and the inner side of each of the suspension electrodes (32), and an anti-corona ring (34) is provided on the outer side of each of the suspension electrodes (32).

2. The electron gun comprising segmented insulating ceramic according to claim 1, wherein: The pressure in the vacuum sealed chamber is less than or equal to 10 -5 Pa.

3. The electron gun comprising segmented insulating ceramic according to claim 1, wherein: The axial lengths of the ceramic segments are non-uniform, so that the suspension electrodes (32) are arranged at non-uniform intervals.

4. The electron gun comprising segmented insulating ceramic according to claim 3, wherein: Along the direction from the anode (2) to the cathode support (5), the axial length of the first ceramic segment is the longest, the second is the second, and the remaining ceramic segments are shorter.

5. The electron gun comprising segmented insulating ceramic according to claim 4, wherein: The remaining ceramic segments have the same axial length.

6. The electron gun comprising segmented insulating ceramic according to claim 1, wherein: The thickness of the shielding ring (33) close to the anode (2) is smaller than the thickness of the portion away from the anode (2), and the portion with the thinner thickness is closer to the ceramic segment (31).

7. The electron gun comprising segmented insulating ceramic according to claim 1, wherein: In the shielding ring (33) connected to each suspension electrode (32), the upper end surface of the shielding ring (33) close to the anode (2) is higher than the upper end surface of the suspension electrode (32) connected thereto.

8. The electron gun comprising segmented insulating ceramic according to claim 1, wherein: All corners of each shielding ring (33) are rounded.

9. The electron gun comprising segmented insulating ceramic according to claim 1, wherein: There is a gap between the anti-corona ring (34) and the segmented insulating ceramic (3).

10. The electron gun comprising segmented insulating ceramic according to claim 1, wherein: The end of the anti-corona ring (34) is in a smooth arc shape.

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