Electron beam generator

Abstract

To provide an electron beam generator capable of suppressing deterioration of the quality of an electron beam.SOLUTION: An electron beam generator 100 includes a cathode 1, an anode 2 disposed opposite the cathode 1, a container 3 electrically connected to the anode 2, an electron-emitting material 4 disposed between the cathode 1 and the anode 2, an insulator 5 connecting the cathode 1 and the container 3, and an auxiliary member 6 for fixing the electron-emitting material 4 to the cathode 1. The cathode 1 includes a surface 1a facing the anode 2. The auxiliary member 6 is configured to fix the electron-emitting material 4 to the surface 1a of the cathode 1.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to electron beam generating devices. [Background technology]

[0002] In an electron beam generator that generates an electron beam by applying a high voltage of several tens of kV or more between electrodes, an electron-emitting material is generally disposed on the surface of the cathode to improve the quality of the electron beam. For example, in an electromagnetic field generator (electron beam generator) described in JP 2023-4882 A (Patent Document 1), an electron-emitting material (electron-emitting material) is disposed on the surface of the cathode electrode (negative electrode). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-4882 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, an adhesive is used to fix the electron-emitting material to the surface of the cathode. This adhesive is applied to all bonding surfaces between the electron-emitting material and the cathode. However, when a large current flows through the adhesive, plasma is generated by the adhesive, generating positive and negative ions from the adhesive. These positive and negative ions travel in random directions from the point of generation, affecting the divergence and contraction of the electron beam. This deteriorates the quality of the electron beam.

[0005] The present disclosure has been made in view of the above-mentioned problems, and its purpose is to provide an electron beam generating device that can suppress deterioration in the quality of the electron beam. [Means for solving the problem]

[0006] The electron beam generator of the present disclosure includes a cathode, an anode disposed opposite the cathode, a container electrically connected to the anode, an electron-emitting material disposed between the cathode and the anode, an insulator connecting the cathode and the container, and an auxiliary member for fixing the electron-emitting material to the cathode. The cathode includes a surface facing the anode. The auxiliary member is configured to fix the electron-emitting material to the surface of the cathode. [Effects of the Invention]

[0007] According to the electron beam generating device of the present disclosure, deterioration of the quality of the electron beam can be suppressed. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically showing the structure of an electron beam generating device according to a first embodiment. [Figure 2] FIG. 10 is a cross-sectional view schematically showing the structure of a modified example of the electron beam generator according to the first embodiment. [Figure 3] FIG. 10 is a cross-sectional view schematically illustrating the structure of an electron beam generating device of a comparative example. [Figure 4] FIG. 10 is an enlarged cross-sectional view schematically showing the periphery of a cathode of an electron beam generator according to a second embodiment. [Figure 5] FIG. 11 is an enlarged cross-sectional view schematically showing the periphery of a cathode of an electron beam generating device according to a third embodiment. [Figure 6] FIG. 10 is a cross-sectional view schematically showing the structure of an electron beam generating device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. In the following, the same or corresponding parts will be denoted by the same reference numerals, and overlapping descriptions will not be repeated.

[0010] Embodiment 1 The structure of an electron beam generator 100 according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view schematically showing the structure of the electron beam generator 100 according to the first embodiment.

[0011] The electron beam generator 100 according to the first embodiment includes a cathode 1, an anode 2, a container 3, an electron-emitting material 4, an insulator 5, and an auxiliary member 6. The electron beam generator 100 according to the first embodiment also includes a high-voltage generating unit 10.

[0012] The cathode 1 is connected to the container 3 via an insulator 5. The cathode 1 includes a surface 1a facing the anode 2. The material of the cathode 1 is generally a conductive material (electrical resistivity of 1 kΩ·m or less). Materials with low electrical resistivity, such as aluminum, copper, stainless steel (SUS), and brass, are used for the material of the cathode 1. However, conductive materials other than those exemplified above can also be used for the material of the cathode 1.

[0013] The anode 2 is disposed opposite the cathode 1. The anode 2 is connected to a container 3. The material of the anode 2 is basically a conductive material (electrical resistivity of 1 kΩ·m or less). Examples of materials that can be used for the anode 2 include aluminum, copper, stainless steel (SUS), brass, as well as metals with a melting point of 500°C or higher, such as tungsten and molybdenum. The shape of the anode can be flexibly changed depending on the device, such as a flat plate, a curved surface, or a metal mesh.

[0014] The container 3 is connected to the cathode 1. The container 3 is electrically connected to the cathode 1. The container 3 is connected to the anode 2. Using a conductive material for the container 3 has the advantage of allowing the device to be constructed simply. For this reason, a highly conductive metal container is generally used for the container 3, but it does not necessarily have to be conductive. In that case, it is necessary to prepare a separate conductive member and wire it to a power source.

[0015] The electron-emitting material 4 is placed between the cathode 1 and the anode 2. The electron-emitting material 4 has a higher electron emission capacity than the cathode 1. The electron-emitting material 4 is mainly made of conductive and non-conductive materials. Carbon fiber is a typical conductive material. Non-conductive materials include cloth and polymers made of organic substances. In addition, there are conductive and non-conductive materials coated with radioactive substances.

[0016] The insulator 5 connects the cathode 1 and the container 3. The insulator 5 is used to insulate the high voltage applied to the cathode 1 and the anode 2. The insulator 5 is made of a material with high electrical resistivity (electrical resistivity of 10 Ω·m or more). The insulator 5 may have a wavy structure to increase the creeping distance in order to suppress creeping discharge.

[0017] The auxiliary member 6 secures the electron-emitting material 4 to the cathode 1. The auxiliary member 6 is configured to secure the electron-emitting material 4 to the surface 1a of the cathode 1. The auxiliary member 6 holds the electron-emitting material 4 between the cathode 1 and the anode 2. The cathode 1 and the electron-emitting material 4 are connected via the auxiliary member 6. The auxiliary member 6 can be made of either a conductive or non-conductive material. If the auxiliary member 6 is made of a non-conductive material, the auxiliary member 6 will have a different potential from the cathode 1, allowing the electric field between the cathode 1 and the anode 2 to be designed using only the cathode 1. This simplifies the design. However, the auxiliary member itself may become plasma, potentially degrading the quality of the electron beam. To avoid this, additional measures, such as modifying the shape or using a high-melting-point material, may be necessary. However, compared to the use of conventional adhesives, the effect on the electron beam is minimal. A conductive material has the advantage of being less likely to become plasma because it has the same potential as the cathode 1 and low resistance. However, it has the disadvantage of complicating the electric field design.

[0018] The high voltage generating unit 10 is configured to apply a high voltage pulse to the cathode 1. When the high voltage generating unit 10 applies a high voltage pulse to the cathode 1, electrons are emitted from the cathode 1 toward the anode 2 by field emission, forming an electron beam.

[0019] Next, a modified example of the electron beam generator 100 according to the first embodiment will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view schematically showing the structure of the modified example of the electron beam generator according to the first embodiment.

[0020] In the modified example of the electron beam generator 100 according to the first embodiment, the auxiliary member 6 has a shape slightly larger than the cathode 1. The auxiliary member 6 fixes the electron-emitting material 4 to the cathode 1 by fitting with the cathode 1 and the electron-emitting material 4.

[0021] Next, the effects of the electron beam generator 100 according to the first embodiment will be described in comparison with a comparative example.

[0022] The structure of the electron beam generator 100 of the comparative example will be described with reference to Fig. 3. Fig. 3 is a cross-sectional view that schematically shows the structure of the electron beam generator 100 of the comparative example.

[0023] In the electron beam generator 100 of the comparative example, an adhesive 8 is used to fix the electron-emitting material 4 to the surface 1a of the cathode 1. The adhesive 8 is applied to the entire bonding surface between the electron-emitting material 4 and the cathode 1.

[0024] In the electron beam generator 100 of the comparative example, when a large current flows through the adhesive 8, plasma is generated by the adhesive 8, generating positive and negative ions caused by the adhesive. These positive and negative ions travel in random directions from the point of generation, affecting the divergence and contraction of the electron beam, which deteriorates the quality of the electron beam.

[0025] In the electron beam generator 100 according to the first embodiment, the auxiliary member 6 is configured to fix the electron-emitting material 4 to the surface 1a of the cathode 1. Therefore, by introducing the auxiliary member 6, rather than applying adhesive 8 to the entire bonding surface between the electron-emitting material 4 and the cathode 1 as in the comparative example, it is possible to fix the electron-emitting material 4 to the surface 1a of the cathode 1 without using adhesive 8 or by reducing the amount of adhesive 8 used. This reduces the effect of plasma due to the adhesive 8, thereby reducing the effect of positive and negative ions caused by the adhesive on the divergence and contraction of the electron beam. This prevents deterioration of the quality of the electron beam.

[0026] Embodiment 2 Unless otherwise specified, embodiment 2 has the same configuration and effects as embodiment 1. Therefore, the same components as embodiment 1 are denoted by the same reference numerals, and description thereof will not be repeated.

[0027] The structure of the electron beam generator 100 according to the second embodiment will be described with reference to Fig. 4. Fig. 4 is an enlarged cross-sectional view schematically showing the periphery of the cathode 1 of the electron beam generator 100 according to the second embodiment.

[0028] The electron beam generator 100 according to the second embodiment is different from the electron beam generator 100 according to the first embodiment shown in FIG. 1 in that a connector 7 is added. The electron beam generator 100 according to the second embodiment further includes the connector 7. The connector 7 is configured to connect the auxiliary member 6 to the cathode 1. The shape of the connector 7 can be, for example, a screw shape or a rod shape, as long as it serves to fix the cathode 1 and the auxiliary member 6 together. The material of the connector 7 may be conductive or non-conductive. Furthermore, in FIG. 4, the connector 7 is embedded in the cathode 1 and the auxiliary member 6 as an example, but the shape of the connector 7 is not limited as long as it has the function of connecting the cathode 1 and the auxiliary member 6 together.

[0029] Next, the effects of the electron beam generator 100 according to the second embodiment will be described.

[0030] In the electron beam generator 100 according to the second embodiment, the connector 7 is configured to connect the auxiliary member 6 to the cathode 1. Therefore, by fixing the auxiliary member 6 using the connector 7, it becomes possible to fix the electron emitting material 4 without using any adhesive.

[0031] Moreover, by sandwiching the electron-emitting material 4 between the cathode 1 and the auxiliary member 6, the electron-emitting material 4 can also be held at the same time.

[0032] Embodiment 3 Unless otherwise specified, embodiment 3 has the same configuration and effects as embodiment 1. Therefore, the same components as embodiment 1 are denoted by the same reference numerals, and description thereof will not be repeated.

[0033] The structure of the electron beam generator 100 according to the third embodiment will be described with reference to Fig. 5. Fig. 5 is an enlarged cross-sectional view schematically showing the periphery of the cathode 1 of the electron beam generator 100 according to the third embodiment.

[0034] The electron beam generator 100 according to the third embodiment differs from the electron beam generator 100 according to the first embodiment shown in FIG. 1 in the shapes of the cathode 1 and the auxiliary member 6. The cathode 1 includes a recess 1b provided on the surface 1a. The auxiliary member 6 includes a protrusion 6a protruding toward the cathode 1. The protrusion 6a of the auxiliary member 6 engages with the recess 1b of the cathode 1, thereby fixing the auxiliary member 6 to the cathode 1. This structure allows the auxiliary member 6 to have a holding function for the cathode 1.

[0035] Next, the effects of the electron beam generator 100 according to the third embodiment will be described.

[0036] In the electron beam generator 100 according to the third embodiment, the auxiliary member 6 is fixed to the cathode 1 by engaging the protrusion 6a of the auxiliary member 6 with the recess 1b of the cathode 1. Therefore, the structure of the auxiliary member 6 itself enables connection to the cathode 1. Therefore, it is possible to fix the electron-emitting material 4 without using any adhesive. Furthermore, the connector 7 of the electron beam generator 100 according to the second embodiment shown in FIG. 4 is not required, which has the advantage of reducing the number of parts.

[0037] Moreover, similarly to the second embodiment, by sandwiching the electron-emitting material 4 between the cathode 1 and the auxiliary member 6, the electron-emitting material 4 can also be held at the same time.

[0038] Embodiment 4 Unless otherwise specified, embodiment 4 has the same configuration and effects as embodiment 1. Therefore, the same components as embodiment 1 are denoted by the same reference numerals, and description thereof will not be repeated.

[0039] The structure of the electron beam generator 100 according to the fourth embodiment will be described with reference to Fig. 6. Fig. 6 is a cross-sectional view schematically showing the structure of the electron beam generator 100 according to the fourth embodiment.

[0040] The electron beam generator 100 according to the fourth embodiment differs from the electron beam generator 100 according to the first embodiment shown in Fig. 1 in the positional relationship of the auxiliary member 6. In the electron beam generator 100 according to the fourth embodiment, the auxiliary member 6 includes a facing surface 6b facing the anode 2. The surface 1a of the cathode 1 and the facing surface 6b of the auxiliary member 6 are arranged on the same plane. In other words, the anode-side surfaces of the cathode 1 and the auxiliary member 6 are arranged on the same plane.

[0041] Next, the effects of the electron beam generator 100 according to the fourth embodiment will be described.

[0042] In the electron beam generator 100 according to the fourth embodiment, the surface 1a of the cathode 1 and the opposing surface 6b of the auxiliary member 6 are arranged on the same plane. Therefore, the electric field distribution between the cathode 1 and the anode 2 becomes more uniform.

[0043] Furthermore, the above embodiments can be combined as appropriate.

[0044] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0045] 1 cathode, 1a surface, 1b recess, 2 anode, 3 container, 4 electron-emitting material, 5 insulator, 6 auxiliary member, 6a protrusion, 6b opposing surface, 7 connector, 8 adhesive, 10 high-voltage generating unit, 100 electron beam generating device.

Claims

1. A cathode; an anode disposed opposite the cathode; a container electrically connected to the anode; an electron-emitting material disposed between the cathode and the anode; an insulator connecting the cathode and the container; an auxiliary member for fixing the electron-emitting material to the cathode; the cathode includes a surface facing the anode; The electron beam generating device, wherein the auxiliary member is configured to fix the electron-emitting material to the surface of the cathode.

2. Further provided with a connector, The electron beam generating device according to claim 1 , wherein the connector is configured to connect the auxiliary member to the cathode.

3. The cathode includes a recess provided on the surface. the auxiliary member includes a protrusion protruding toward the cathode, 2. The electron beam generating apparatus according to claim 1, wherein the auxiliary member is fixed to the cathode by engaging the protrusion of the auxiliary member with the recess of the cathode.

4. the auxiliary member includes an opposing surface facing the anode, 2. The electron beam generating apparatus according to claim 1, wherein the surface of the cathode and the opposing surface of the auxiliary member are arranged on the same plane.

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