Gyrotron cathode structure and its method for suppressing secondary electron emission in non-emission regions

Abstract

This invention discloses a gyrotron cathode structure and a method for suppressing secondary electron emission in its non-emission region. The method includes: cleaning the cathode heat shield component; sintering the cathode heat shield component; and coating the outer surface of the cathode heat shield component with a thin film material to form a thin film layer. When used, this method overcomes the problem in existing technologies where the presence of extra electrons alters the space charge distribution during gyrotron operation, leading to a decrease in the electron beam quality and interference with the normal interaction between the high-frequency field and the electron beam. More seriously, this could excite unwanted oscillation modes or cause a decrease in the gyrotron's output power.

Description

Technical Field

[0001] This invention relates to the field of vacuum device manufacturing technology, specifically to a gyrotube cathode structure and a method for suppressing secondary electron emission in its non-emission region. Background Technology

[0002] Thermonuclear fusion power generation is one of humanity's "ultimate dreams" for energy. Currently, it is at a critical stage, moving from scientific feasibility verification to engineering feasibility verification. For example, my country's fully superconducting tokamak nuclear fusion experimental device has repeatedly set world records in plasma confinement and heating. Plasma heating utilizes microwave heating methods, and the microwave source is a megawatt-class gyrotron tube.

[0003] A gyrotron is a vacuum device, and the cathode, as the electron emission source of the vacuum device, is usually a hot cathode, with the cathode typically operating at a temperature of 950°C. C~1050 Within the range of S. At such high temperatures, the cathode emitter evaporates onto the thermal shield of the non-emitting region of the cathode. When the gyrotron is in operation, this causes electron emission on the thermal shield of the non-emitting region. On the other hand, the gyrotron electron gun is a magnetron-injected electron gun. Due to the presence of an external magnetic field, there is a possibility of electron backfire from the cathode. This causes secondary electron emission from the thermal shield of the non-emitting region. The presence of all these extra electrons will change the space charge distribution, causing a decrease in the electron beam mass of the gyrotron. This will interfere with the normal interaction process between the high-frequency field and the electron beam. More seriously, it may excite unwanted oscillation modes or cause a decrease in the output power of the gyrotron.

[0004] Therefore, the present invention urgently needs to solve the problem of providing a gyro cathode structure that can solve the above problems and a method for suppressing secondary electron emission in the non-emission region. Summary of the Invention

[0005] To address the aforementioned technical problems, the purpose of this invention is to overcome the problem that in the prior art, when a gyroscope is in operation, the presence of additional electrons alters the space charge distribution, causing a decrease in the electron beam quality of the gyroscope, which in turn interferes with the normal interaction process between the high-frequency field and the electron beam. More seriously, it may excite unwanted oscillation modes or lead to a decrease in the output power of the gyroscope. Therefore, this invention provides a gyroscope cathode structure that can solve the above problems and a method for suppressing secondary electron emission in the non-emission region.

[0006] To achieve the above objectives, the present invention provides a gyrotube cathode structure, the structure comprising: a cathode heat shield component, a cathode emitter, and a hot wire assembly lead; the surface of the cathode heat shield component is coated with a thin film layer of thin film material having a low secondary electron emission coefficient.

[0007] Preferably, the material of the thin film layer is hafnium metal.

[0008] Preferably, the thickness of the thin film layer is 8~9 μm.

[0009] The present invention also provides a method for suppressing secondary electron emission in the non-emission region of a gyrotube cathode, characterized in that the method comprises: The cathode heat shield components are cleaned. The cathode heat shield component is subjected to sintering treatment; A thin film material coating operation is performed on the outer surface of the cathode heat shield component.

[0010] Preferably, the cleaning process for the cathode heat shield components includes the following steps: The surface of the cathode heat shield component is degreased using ultrasonic waves; The oxide layer on the surface of the cathode heat shield components is removed by cleaning with an acid solution.

[0011] Preferably, the sintering process for the cathode heat shield component includes the following steps: The cathode heat shield parts are annealed and sintered in a high-temperature sintering furnace.

[0012] Preferably, during the sintering process of the cathode heat shield component, The annealing temperature should be controlled within the range of 950℃~1100℃; The annealing time should be controlled within the range of 30 min to 35 min.

[0013] Preferably, the high-temperature sintering furnace is a vacuum furnace or a hydrogen furnace.

[0014] Preferably, the thin film material coating operation on the outer surface of the cathode heat shield component includes the following steps: Thin film materials are deposited on the outer surface of the cathode heat shield component using magnetron sputtering or electron beam evaporation; among which... The thickness of the thin film material coating is 8~9 μm; Evaporation time: 45 min to 90 min.

[0015] Preferably, after applying a thin film material coating to the outer surface of the cathode heat shield component, the method further includes: Assembled to form a gyrotube cathode; The cathode of the gyrotube was tested.

[0016] According to the above technical solution, the beneficial effects of the gyro cathode structure and the method for suppressing secondary electron emission in the non-emission region provided by the present invention are as follows: a thin film material with a low secondary electron emission coefficient is coated on the surface of the thermal shield in the non-emission region of the cathode. This thin film material has a strong adsorption effect on electrons and can suppress the emission of low-energy secondary electrons. The coating is carried out by magnetron sputtering or electron beam evaporation, which is simple to operate and easy to master.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description section; and all parts not covered in the present invention are the same as or can be implemented using the prior art. Attached Figure Description

[0018] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of a gyrotube cathode structure provided in a preferred embodiment of the present invention; Figure 2 This is a flowchart of a method for suppressing secondary electron emission in the non-emission region of a gyrotube cathode, provided in a preferred embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures 1. Cathode heat shield components 2. Hot wire assembly leads 3. Cathode emitter 4. Thin film layer Detailed Implementation The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0020] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "inner," and "outer" in the terminology represent only the orientation of the term in its normal use or are common terms understood by those skilled in the art, and should not be regarded as limitations on the term.

[0021] Example 1: like Figure 1 As shown, the present invention provides a gyrotube cathode structure, the structure comprising: a cathode heat shield component 1, a cathode emitter 3, and a hot wire assembly lead 2; the surface of the cathode heat shield component 1 is coated with a thin film layer with a low secondary electron emission coefficient.

[0022] The material of the thin film layer is hafnium metal; the thickness of the thin film layer 4 is 8~9 μm.

[0023] In the above scheme, the thin film layer 4 can have a strong adsorption effect on electrons, which can suppress the emission of low-energy secondary electrons.

[0024] Example 2: like Figure 2 As shown, the present invention provides a method for suppressing secondary electron emission in the non-emission region of a gyrotube cathode, characterized in that the method includes: Step S101: Clean the cathode heat shield component 1; Step S102: The cathode heat shield component 1 is subjected to sintering treatment; Step S103: Apply a thin film material coating to the outer surface of the cathode heat shield component 1 to form a thin film layer 4.

[0025] In the above scheme, the surface of the cathode heat shield component is cleaned before coating with a thin film material to ensure its cleanliness and prevent impurities from affecting the inhibition effect of the thin film material. The sintering process further cleans the component surface. Coating with a thin film material can suppress secondary electron emission in the non-emission area of ​​the cathode, improve the electron beam emission quality of the cathode, and facilitate the normal operation of the gyrotron device.

[0026] In a preferred embodiment of the present invention, the cleaning process for the cathode heat shield components includes the following steps: The surface of the cathode heat shield component is degreased using ultrasonic waves; The oxide layer on the surface of the cathode heat shield components is removed by cleaning with an acid solution.

[0027] In a preferred embodiment of the present invention, the sintering process of the cathode heat shield component includes the following steps: The cathode heat shield parts are annealed and sintered in a high-temperature sintering furnace.

[0028] In a preferred embodiment of the present invention, during the sintering process of the cathode heat shield component... The annealing temperature should be controlled within the range of 950℃~1100℃; The annealing time should be controlled within the range of 30 min to 35 min.

[0029] In a preferred embodiment of the present invention, the high-temperature sintering furnace is a vacuum furnace or a hydrogen furnace.

[0030] In a preferred embodiment of the present invention, the thin film material coating operation on the outer surface of the cathode thermal shield component includes the following steps: Thin film materials are deposited on the outer surface of the cathode heat shield component using magnetron sputtering or electron beam evaporation; among which... The thickness of the thin film layer coated with the thin film material is 8~9 μm; Evaporation time: 45 min to 90 min.

[0031] In a preferred embodiment of the present invention, after coating the outer surface of the cathode thermal shield component with a thin film material, the method further includes: Step S104: Assemble to form a gyrotube cathode; Step S105: Test the cathode of the gyrotube.

[0032] In the above scheme, according to Figure 1 The structure involves assembling the cathode heat shield component 1 coated with a thin film layer 4, the cathode emitter 3, and the hot wire assembly 2 to complete the cathode assembly. Afterward, the gyrotube cathode is installed on the cathode testing equipment for emission testing to determine its qualification. Qualified gyrotube cathode assemblies have been selected. In summary, the gyrotron cathode structure and its method for suppressing secondary electron emission in the non-emission region provided by this invention are simple to operate and easy to master. By using magnetron sputtering or electron beam evaporation to coat a thin film material with a low secondary electron emission coefficient, the purpose of suppressing secondary electron emission in the non-emission region of the cathode is achieved, thereby improving the quality of cathode electron beam emission and facilitating the normal operation of the gyrotron device.

[0033] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0034] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0035] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A gyrotube cathode structure, the structure comprising: A cathode heat shield component, a cathode emitter, and a hot wire assembly lead; characterized in that the surface of the cathode heat shield component is coated with a thin film layer having a low secondary electron emission coefficient.

2. The gyrotube cathode structure according to claim 1, characterized in that, The material of the thin film layer is hafnium metal.

3. The gyrotube cathode structure according to claim 1, characterized in that, The thickness of the thin film layer is 8~9 μm.

4. A method for suppressing secondary electron emission in the non-emission region of a gyrotube cathode according to any one of claims 1-3, characterized in that, The method includes: The cathode heat shield components are cleaned. The cathode heat shield component is subjected to sintering treatment; A thin film material coating operation is performed on the outer surface of the cathode heat shield component to form a thin film layer.

5. The method for suppressing secondary electron emission in the non-emission region of a gyrotube cathode according to claim 4, characterized in that, The cleaning process for the cathode heat shield components includes the following steps: The surface of the cathode heat shield component is degreased using ultrasonic waves; The oxide layer on the surface of the cathode heat shield components is removed by cleaning with an acid solution.

6. The method for suppressing secondary electron emission in the non-emission region of a gyrotube cathode according to claim 4, characterized in that, The sintering process for the cathode heat shield components includes the following steps: The cathode heat shield parts are annealed and sintered in a high-temperature sintering furnace.

7. The method for suppressing secondary electron emission in the non-emission region of a gyrotube cathode according to claim 4, characterized in that, During the sintering process of cathode heat shield components The annealing temperature should be controlled within the range of 950℃~1100℃; The annealing time should be controlled within the range of 30 min to 35 min.

8. The method for suppressing secondary electron emission in the non-emission region of a gyrotube cathode according to claim 6, characterized in that, The high-temperature sintering furnace is a vacuum furnace or a hydrogen furnace.

9. The method for suppressing secondary electron emission in the non-emission region of a gyrotube cathode according to claim 6, characterized in that, The process of coating the outer surface of the cathode heat shield component with a thin film material includes the following steps: A thin film layer is formed by depositing a thin film material on the outer surface of a cathode thermal shield component using magnetron sputtering or electron beam evaporation; wherein... The thickness of the thin film layer is 8~9 μm; The vapor deposition time for the thin film layer is 45 min to 90 min.

10. The method for suppressing secondary electron emission in the non-emission region of a gyrotube cathode according to claim 4, characterized in that, After applying a thin film material coating to the outer surface of the cathode thermal shield component, the method further includes: Assembled to form a gyrotube cathode; The cathode of the gyrotube was tested.

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