Electron gun
By adopting a planar spiral structure of filament and a reasonably designed gate structure and focus cylinder, the problem of poor uniformity of the electronic source on the microchannel plate surface is solved, and a large area of MCP electronic brushing effect is achieved.
Patent Information
- Application Number
- CN202422477347.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-11
- Publication Date
- 2025-08-08
- Estimated Expiration
- 2034-10-11
AI Technical Summary
In the prior art, the surface electron source uniformity of the microchannel plate is poor, making it difficult to achieve large-area MCP electronic cleaning.
A filament with a planar spiral structure is adopted, combined with a cylindrical gate structure, an insulating ring and a focusing cylinder, and the electron divergence and focus are achieved by adjusting the voltage of each structure to form a uniform surface electron source.
A larger area and a more uniform surface electron source is achieved, improving the electronic brushing effect of MCP.
Smart Images
Figure CN223206216U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of microchannel plate degassing treatment, in particular to an electron gun. Background Art
[0002] In order to thoroughly degas the microchannel plate, it is necessary to design a surface electron source with good uniformity and sufficiently large output electron flow to achieve large-area MCP (Microchannel Plate) electronic cleaning.
[0003] like Figure 1 As shown, a V-shaped electron gun structure is currently used, capable of cleaning a Φ30mm MCP. The electron gun has an outer diameter of Φ35mm and an adjustable cleaning current. The principle behind this filament structure can be summarized as follows: When the filament is energized to reach its emission temperature, it emits electrons in all directions. Horizontally emitted electrons are absorbed by the cathode shield due to electrostatic equilibrium. Electron beams at an angle to the horizontal are emitted from the cathode shield aperture and deflected by the accelerating electric field. Of the vertically emitted electrons, only the electron beam with a Φ4mm aperture moves toward the MCP under the influence of the accelerating electric field; the remaining electrons are absorbed by the shield, achieving a beam-limiting effect. By determining the shield aperture and the distance between the filament and the MCP, and by controlling the relative potential between the shield and the MCP, the desired amount of electrons reaching the MCP surface can be controlled, enabling an adjustable cleaning current. However, the uniformity of the surface electron source produced by this structure is poor. Utility Model Content
[0004] The purpose of the utility model is to provide an electron gun capable of generating a larger and more uniform surface electron source.
[0005] To achieve the above objectives, the present invention provides the following technical solutions:
[0006] The utility model provides an electron gun, comprising a filament, a grid structure, an insulating ring and a focusing cylinder;
[0007] The gate structure is cylindrical, has a first opening at one end and a second opening at the other end, and the inner diameter of the gate structure gradually increases along the direction from the first opening to the second opening;
[0008] One end of the insulating ring is connected to the second opening of the grid structure, and the other end is connected to the focusing cylinder;
[0009] The filament is bent into a planar spiral structure, and the filament is arranged in the grid structure.
[0010] Furthermore, the axis of the planar spiral structure is perpendicular to the first opening and the second opening;
[0011] The diameter of the planar spiral structure is 7.5-8.5 mm;
[0012] The distance between the planar spiral structure and the first opening along its own axis is 9.1-9.3 mm.
[0013] Furthermore, a surface of the filament facing the second opening is an emitting surface, and a cross section of the filament is a rectangle.
[0014] Furthermore, the spacing between each turn of the filament is 0.07-0.09 mm.
[0015] Furthermore, the length of the gate structure along its own axis is 31-33 mm;
[0016] The inner diameter of the first opening is 9-11 mm, and the outer diameter of the first opening is 13-15 mm;
[0017] The inner diameter of the second opening is 35-36 mm, and the outer diameter of the second opening is 37-38 mm.
[0018] Furthermore, the length of the focusing tube along its own axis is 26-28 mm;
[0019] The inner diameter of the focusing tube is 35-36 mm, and the outer diameter of the focusing tube is 37-38 mm.
[0020] Furthermore, a circular ring is provided at one end of the focusing cylinder away from the grid structure, and the inner diameter of the circular ring is smaller than the inner diameter of the focusing cylinder.
[0021] Furthermore, the inner diameter of the ring is 32-34 mm, and the outer diameter of the ring is 37-38 mm.
[0022] Furthermore, it also includes an anode receiving surface, the distance between the anode receiving surface and the second opening is 119-121 mm, and the diameter of the anode receiving surface is 37-38.
[0023] Furthermore, the voltage applied to the gate structure is 100-300V;
[0024] The voltage applied to the filament is 400-600V;
[0025] The voltage applied to the focusing cylinder is 150-350V;
[0026] The voltage applied to the anode receiving surface is 300-500V.
[0027] The electron gun provided by the utility model can produce the following beneficial effects:
[0028] When the electron gun provided by this utility model is in use, a voltage is applied to both ends of the filament, causing the filament to begin heating. Once the temperature reaches a certain level, electrons overflow, placing the electron input surface of the MCP at a high potential relative to the filament. The electrons then pass through the grid structure, which disperses the electrons emitted by the filament. The electrons then enter a focusing cylinder, which focuses them and ultimately moves them to the input surface of the MCP. During this process, the insulating ring insulates the grid structure from the focusing cylinder.
[0029] Compared with the prior art, the filament in the electron gun provided by the present invention adopts a planar spiral structure. The boundary of the planar spiral filament varies greatly, but the temperature in the middle is very uniform, so the surface uniformity is very good. Compared with the "V"-shaped filament, it can produce a larger and more uniform surface electron source. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0031] Figure 1 It is a structural diagram of an electron gun in the prior art;
[0032] Figure 2 A schematic structural diagram of an electron gun provided in an embodiment of the present utility model;
[0033] Figure 3 A schematic diagram of electron emission simulation of an electron gun provided in an embodiment of the present utility model;
[0034] Figure 4 A perspective view of a three-dimensional structure of a filament provided in an embodiment of the utility model;
[0035] Figure 5 This is a top view of a filament provided in an embodiment of the present utility model.
[0036] Icons: 1-filament; 11-emitting surface; 2-grid structure; 21-first opening; 22-second opening; 3-insulating ring; 4-focusing tube; 5-circular ring; 6-anode receiving surface. DETAILED DESCRIPTION
[0037] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.
[0038] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or relationships, are based on the positions or relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0039] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.
[0040] The following is a detailed description of the specific embodiments of the present invention in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.
[0041] This embodiment provides an electron gun, such as Figure 2 As shown, it includes a filament 1, a grid structure 2, an insulating ring 3 and a focusing tube 4;
[0042] The gate structure 2 is cylindrical, with a first opening 21 at one end and a second opening 22 at the other end. The inner diameter of the gate structure 2 gradually increases along the direction from the first opening 21 to the second opening 22.
[0043] One end of the insulating ring 3 is connected to the second opening 22 of the grid structure 2, and the other end is connected to the focusing cylinder 4;
[0044] The filament 1 is bent into a planar spiral structure and is disposed in the grid structure 2 .
[0045] like Figure 2 and Figure 3As shown, when the electron gun provided in this embodiment is in use, a voltage is applied to both ends of the filament 1, the filament 1 begins to heat up, and when the filament 1 reaches a certain temperature, electrons will overflow, so that the electron input surface of the MCP is at a high potential relative to the filament. Then, the electrons emitted by the filament 1 pass through the gate structure 2, and the gate structure 2 has a divergent effect on the electrons emitted by the filament 1. Then, the electrons enter the focusing tube 4, and the focusing tube 4 focuses the electrons, and finally the electrons move to the input surface of the MCP.
[0046] In the above process, since the voltages applied to the grid structure 2 and the focusing cylinder 4 are different, the insulating ring 3 serves to insulate the grid structure 2 from the focusing cylinder 4 .
[0047] It should be noted that the principle of electron overflow after the above-mentioned filament 1 reaches a certain temperature is that the speed of a large number of free electrons inside the metal is Fermi-Dirac distribution. Since the energy of the electrons is lower than the surface potential barrier of the electrons, the electrons are usually bound in the metal and require a certain amount of energy to cross the potential barrier. The minimum value of this energy is the work function of the metal. In the above embodiment, by heating the filament 1, the electrons therein obtain energy that can overcome the surface potential barrier, thereby overflowing the surface of the filament 1.
[0048] Compared with the prior art, the filament 1 in the electron gun provided in this embodiment adopts a planar spiral structure. The boundary of the planar spiral filament 1 varies greatly, but the temperature in the middle is very uniform, so the surface uniformity is very good. Compared with the "V"-shaped filament, it can produce a larger and more uniform surface electron source.
[0049] The filament 1 is described in detail below:
[0050] In an optional embodiment, the axis of the planar spiral structure is perpendicular to the first opening 21 and the second opening 22 to ensure that the electrons overflowing from the filament 1 are as parallel to the axes of the first opening 21 and the second opening as possible.
[0051] In a preferred embodiment, the axis of the planar spiral structure, the axis of the first opening 21 and the axis of the second opening 22 coincide with each other, ensuring that the filament 1 can be located at the center of the grid structure 2 in the radial direction of the first opening 21 and the second opening 22 .
[0052] In an optional embodiment, the diameter of the planar spiral structure is 7.5-8.5 mm, specifically 7.5 mm, 8 mm or 8.5 mm.
[0053] In a preferred embodiment, the diameter of the planar helical structure is 8 mm.
[0054] In an optional embodiment, the distance between the planar spiral structure and the first opening 21 along its own axial direction is 9.1-9.3 mm, specifically 9.1 mm, 9.2 mm or 9.3 mm.
[0055] In a preferred embodiment, the distance between the planar spiral structure and the first opening 21 along its own axial direction is 9.2 mm.
[0056] In an optional embodiment, the surface of the filament 1 facing the second opening 22 is the emission surface 11 , and the material of the filament 1 is tungsten.
[0057] After the filament 1 is pressurized and reaches a certain temperature, the electrons emitted from the emission surface 11 will first pass through the gate structure 2, which can achieve electron divergence.
[0058] Specifically, the cross section of a single filament 1 is rectangular, such as Figure 4 and Figure 5 As shown, the planar spiral structure can be considered to be formed by gradually winding a single filament 1 around an axis.
[0059] In an optional embodiment, the long side of the rectangle may be 0.4-0.6 mm, and the short side of the rectangle may be 0.11-0.13 mm.
[0060] In a preferred embodiment, the long side of the rectangle is 0.5 mm, and the short side of the rectangle is 0.12 mm.
[0061] It can be understood that the side surface of the filament 1 corresponding to one of the short sides of the rectangle forms the emission surface 11 , and the side surfaces of the filament 1 corresponding to the long sides of the rectangle are arranged around the axis of the planar spiral structure.
[0062] In an optional embodiment, each turn of the filament 1 is wound at equal intervals, and the spacing between each turn of the filament 1 is 0.07-0.09 mm, specifically 0.07 mm, 0.08 mm or 0.09 mm.
[0063] In a preferred embodiment, the spacing between each turn of the filament 1 is 0.08 mm.
[0064] The gate structure 2 is described in detail below:
[0065] In an optional embodiment, the length of the gate structure 2 along its own axial direction may be 31-33 mm, specifically 31 mm, 32 mm or 33 mm.
[0066] In a preferred embodiment, the length of the gate structure 2 along its own axial direction is 32 mm.
[0067] like Figure 2As shown, the gate structure 2 can be approximately regarded as a trumpet shape.
[0068] In an optional embodiment, the inner diameter of the first opening 21 may be 9-11 mm, and the outer diameter of the first opening 21 may be 13-15 mm.
[0069] In a preferred embodiment, the inner diameter of the first opening 21 is 10 mm, and the outer diameter of the first opening 21 is 14 mm, that is, the wall thickness of the gate structure 2 at the first opening 21 is 4 mm.
[0070] In an optional embodiment, the inner diameter of the second opening 22 may be 35-36 mm, and the outer diameter of the second opening 22 may be 37-38 mm.
[0071] In a preferred embodiment, the inner diameter of the second opening 22 is 35.745 mm, and the outer diameter of the second opening 22 is 37.644 mm, that is, the wall thickness of the gate structure 2 at the second opening 22 is 1.899 mm.
[0072] The insulating ring 3 is described in detail below:
[0073] In an optional embodiment, the thickness of the insulating ring 3 along its own axial direction is 0.9-1.1 mm, specifically 0.9 mm, 1 mm or 1.1 mm.
[0074] In a preferred embodiment, the thickness of the insulating ring 3 along its own axial direction is 1 mm.
[0075] The insulating ring 3 is made of insulating material, such as ceramic.
[0076] The focusing tube 4 is described in detail below:
[0077] In an optional embodiment, the length of the focusing tube 4 along its own axial direction may be 26-28 mm, specifically 26 mm, 27 mm or 28 mm.
[0078] In a preferred embodiment, the length of the focusing tube 4 along its own axis is 27 mm, that is, the length of the focusing tube 4 can be slightly shorter than the gate structure 2, and the focusing tube 4 plays a role in focusing electrons.
[0079] like Figure 2 As shown, the focusing tube 4 can adopt a cylindrical tube structure, and the inner diameter is equal at all points along its axial direction.
[0080] In an optional embodiment, the inner diameter of the focusing tube 4 may be 35-36 mm, and the outer diameter of the focusing tube 4 may be 37-38 mm.
[0081] In a preferred embodiment, the inner diameter of the focusing tube 4 is 35.644 mm, and the outer diameter of the focusing tube 4 is 37.644 mm, that is, the wall thickness of the focusing tube 4 is 2 mm.
[0082] In an optional embodiment, if Figure 2 As shown, a circular ring 5 may be further provided at one end of the focusing tube 4 away from the grid structure 2 . The inner diameter of the circular ring 5 is smaller than the inner diameter of the focusing tube 4 . The circular ring 5 can constrain the emitted electrons at the edge portion.
[0083] In an optional embodiment, the inner diameter of the ring 5 may be 32-34 mm, and the outer diameter of the ring 5 may be 37-38 mm.
[0084] In a preferred embodiment, the inner diameter of the ring 5 is 33 mm, the outer diameter of the ring 5 is 37.644 mm, and the thickness of the ring 5 along its own axis is 0.01 mm.
[0085] In an optional embodiment, the electron gun may further include an anode receiving surface 6 .
[0086] Specifically, the distance between the anode receiving surface 6 and the second opening 22 is 119-121 mm, and the diameter of the anode receiving surface 6 is 37-38 mm.
[0087] In a preferred embodiment, the distance between the anode receiving surface 6 and the second opening 22 is 120 mm, and the diameter of the anode receiving surface 6 is 37.644 mm, so as to be able to fully receive electrons.
[0088] The following specifically describes the magnitudes of the voltages applied to the filament 1, the grid structure 2, the insulating ring 3, and the focusing tube 4:
[0089] When in use, the size of the electron beam spot incident on the MCP input surface can be changed by adjusting the voltage of each structure.
[0090] In an optional embodiment, the voltage applied to the filament 1 is 400-600V, specifically 400V, 450V, 500V, 550V or 600V.
[0091] In a preferred embodiment, the voltage applied to the filament 1 is 500V.
[0092] In an optional embodiment, the voltage applied to the gate structure 2 is 100-300V, specifically 100V, 150V, 200V, 250V or 300V.
[0093] In a preferred embodiment, the voltage applied to the gate structure 2 is 200V.
[0094] In an optional embodiment, the voltage applied to the focusing cylinder 4 is 150-350V, specifically 150V, 200V, 250V, 300V or 350V.
[0095] In a preferred embodiment, the voltage applied to the focusing cylinder 4 is 250V.
[0096] In an optional embodiment, the voltage applied to the anode receiving surface 6 is 300-500V, specifically 300V, 350V, 400V, 450V or 500V.
[0097] In a preferred embodiment, the voltage applied to the anode receiving surface 6 is 400V.
[0098] The above voltage enables the electron gun to finally obtain a uniform electron beam distribution with a diameter greater than 30 mm.
[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. An electron gun, characterized in that It comprises a filament (1), a grid structure (2), an insulating ring (3) and a focusing tube (4); The gate structure (2) is cylindrical, one end of the gate structure (2) has a first opening (21), the other end has a second opening (22), and the inner diameter of the gate structure (2) gradually increases along the direction from the first opening (21) to the second opening (22); One end of the insulating ring (3) is connected to the second opening (22) of the grid structure (2), and the other end is connected to the focusing cylinder (4); The filament (1) is bent into a planar spiral structure, and the filament (1) is arranged in the grid structure (2).
2. The electron gun according to claim 1, wherein The axis of the planar helical structure is perpendicular to the first opening (21) and the second opening (22); The diameter of the planar spiral structure is 7.5-8.5 mm; The distance between the planar spiral structure and the first opening (21) along its own axial direction is 9.1-9.3 mm.
3. The electron gun according to claim 1, wherein The surface of the filament (1) facing the second opening (22) is an emission surface (11), and the cross section of the filament (1) is a rectangle.
4. The electron gun according to claim 1, wherein The spacing between each turn of the filament (1) is 0.07-0.09 mm.
5. The electron gun according to claim 1, wherein The length of the gate structure (2) along its own axial direction is 31-33 mm; The inner diameter of the first opening (21) is 9-11 mm, and the outer diameter of the first opening (21) is 13-15 mm; The inner diameter of the second opening (22) is 35-36 mm, and the outer diameter of the second opening (22) is 37-38 mm.
6. The electron gun according to claim 1, wherein The focusing tube (4) has an axial length of 26-28 mm. The inner diameter of the focusing tube (4) is 35-36 mm, and the outer diameter of the focusing tube (4) is 37-38 mm.
7. The electron gun according to claim 1, wherein A circular ring (5) is provided at one end of the focusing cylinder (4) facing away from the grid structure (2); the inner diameter of the circular ring (5) is smaller than the inner diameter of the focusing cylinder (4).
8. The electron gun according to claim 7, wherein The inner diameter of the ring (5) is 32-34 mm, and the outer diameter of the ring (5) is 37-38 mm.
9. The electron gun according to any one of claims 1 to 8, characterized in that: It also includes an anode receiving surface (6), the distance between the anode receiving surface (6) and the second opening (22) is 119-121 mm, and the diameter of the anode receiving surface (6) is 37-38 mm.
10. The electron gun according to claim 9, characterized in that The voltage applied to the gate structure (2) is 100-300V; The voltage applied to the filament (1) is 400-600V; The voltage applied to the focusing cylinder (4) is 150-350V; The voltage applied to the anode receiving surface (6) is 300-500V.