Cathode control electron gun structure for klystron

Abstract

The invention discloses a cathode control electron gun structure for a klystron, which comprises a shell, and a cathode assembly and a focusing electrode which are arranged in the shell, the focusing electrode is connected with the cathode assembly through a sleeve, a Kovar part is arranged in the shell, and an adjusting mechanism for applying pressure to the Kovar part is arranged on the shell. The kovar part is arranged to deform after being subjected to pressure applied by the adjusting mechanism, so that the positions of the cathode assembly and the focusing electrode relative to the shell are changed. According to the cathode control electron gun structure for the klystron, the adjusting mechanism is arranged to be matched with the Kovar part, the Kovar part can flexibly adjust deformation in four directions, and in an electron optical system of the klystron, the distance, the incident angle and the like of an electron beam relative to an anode and a channel are changed; the method has the advantage that the electron circulation rate can be dynamically adjusted.

Description

Technical Field

[0001] The present invention belongs to the technical field of microwave electro-vacuum devices, and particularly relates to a cathode-controlled electron gun structure for a klystron. Background Art

[0002] Klystrons are applied in multiple scientific fields such as radar navigation, microwave communication, meteorological research, television broadcasting, microwave remote sensing, space technology, plasma heating, microwave heating, microwave weapons, accelerators, etc. due to their advantages of high power, high gain, and high reliability.

[0003] For the klystron electron gun, to ensure the long life of the electron gun and improve the working stability, it is first necessary to be strongly guaranteed from the selection of the cathode. The cathode is selected with an extremely low working current density to ensure the emission ability within the cathode life time, and at the same time, it can reduce the working temperature of the cathode, greatly extend the service life of the cathode, and improve the reliability of the klystron.

[0004] The permanent magnet uniform magnetic field adopted by the klystron is different from that of the general traveling wave tube in adjusting the electron circulation rate. The general traveling wave tube adjusts the electron circulation rate by adjusting the magnetic system, while the general klystron adjusts the circulation rate by adjusting the electron gun. Therefore, it is very meaningful to design an electron gun with high structural strength and adjustable electron circulation rate.

[0005] For example, the patent document with the publication number CN109494141A discloses a suspended grid-controlled multi-beam klystron electron gun structure, which consists of a cathode cylinder assembly composed of multiple single cathodes arranged in parallel and vertically. Above the cathode cylinder assembly, a thinned and perforated control grid is suspended parallel to the surface of the assembly, and a porous anode is at the top. The technical solution disclosed in this patent document also cannot solve the above-mentioned technical problems. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a cathode-controlled electron gun structure for a klystron, aiming to meet the requirements of long life, stable and reliable operation, and adjustable electron circulation rate of the klystron.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a cathode-controlled electron gun structure for a klystron, including a housing and a cathode assembly and a focusing electrode arranged in the housing. The focusing electrode is connected to the cathode assembly through a sleeve. A kovar part is arranged inside the housing, and an adjusting mechanism for applying pressure to the kovar part is arranged on the housing. The kovar part is configured to deform after receiving the pressure applied by the adjusting mechanism, so that the relative positions of the cathode assembly and the focusing electrode with respect to the housing change.

[0008] The adjusting mechanism includes a first disk, a second disk arranged opposite to the first disk, and adjusting bolts connecting the first disk and the second disk, and the adjusting bolts are in contact with the kovar part.

[0009] A plurality of the adjusting bolts are provided, and all the adjusting bolts are evenly distributed in the circumferential direction.

[0010] Four adjusting bolts are provided, and all the adjusting bolts are evenly distributed in the circumferential direction.

[0011] The sleeve is made of cupronickel, and the sleeve, the focusing electrode and the cathode assembly are connected and fixed together by laser welding.

[0012] The cathode assembly adopts a 10mm reserve type barium tungsten cathode, and the emission current density during the operation of the cathode assembly is 1.2A / cm 2 。

[0013] The front end of the housing is welded to the slow-wave end cap by argon arc welding, and the electrode lead is led out through the insulating terminal assembly at the rear end of the sleeve, and the insulating terminal assembly is hermetically welded to the sleeve by argon arc welding.

[0014] The focusing electrode is made of oxygen-free copper material.

[0015] The kovar part is U-shaped, and the kovar part is processed by spinning.

[0016] For the cathode-controlled electron gun structure of the klystron of the present invention, by setting the cooperation of the adjusting mechanism and the kovar part, the kovar part can flexibly adjust the deformation in four directions. In the electron optical system of the klystron, it will cause changes in the distance between the electron beam and the anode and the channel, the incident angle, etc., and has the advantage of dynamically adjusting the electron flow rate, and is suitable for single-beam klystrons. Description of the Drawings

[0017] This specification includes the following drawings, and the shown contents are respectively:

[0018] Figure 1 is a cross-sectional view of the cathode-controlled electron gun structure of the present invention;

[0019] Figure 2 is a front view of the cathode-controlled electron gun structure of the present invention;

[0020] The marks in the figure are: 1. Cathode assembly; 2. Focusing electrode; 3. Laser welding position; 4. Sleeve; 5. Housing; 6. Insulating terminal assembly; 7. Electrode lead; 8. First disk; 9. Second disk; 10. Adjusting bolt; 501. Kovar part; 502. Induction heating welding and sealing position; 503. Electrode lead argon arc welding and sealing position. Detailed Embodiments

[0021] The following will, with reference to the accompanying drawings, further elaborate on the specific implementation manners of the present invention through the description of embodiments, aiming to help those skilled in the art have a more complete, accurate, and in-depth understanding of the concept and technical solutions of the present invention and facilitate its implementation.

[0022] It should be noted that in the following embodiments, the "first" and "second" do not represent an absolute distinction relationship in terms of structure and / or function, nor do they represent the execution order of precedence, but are merely for the convenience of description.

[0023] As Figure 1 and Figure 2 shown, the present invention provides a cathode-controlled electron gun structure for a klystron, including a housing 5, a cathode assembly 1 and a focusing electrode 2 disposed within the housing 5. The focusing electrode 2 and the cathode assembly 1 are connected by a sleeve 4. A kovar part 501 is disposed inside the housing 5, and an adjusting mechanism for applying pressure to the kovar part 501 is provided on the housing 5. The kovar part 501 is made of kovar material and has flexibility. The kovar part 501 is configured to deform after being subjected to the pressure applied by the adjusting mechanism, causing a change in the relative positions of the cathode assembly 1 and the focusing electrode 2 with respect to the housing 5.

[0024] Specifically, as Figure 1 shown, the focusing electrode 2 has a stepped structure. The sleeve 4 is made of cupronickel, and the sleeve 4, the focusing electrode 2, and the cathode assembly 1 are connected and fixed together by laser welding. The cathode assembly 1 is located inside the focusing electrode 2, and the cathode assembly 1 is connected to an electrode lead 7, and the electrode lead 7 passes through the sleeve 4.

[0025] As Figure 1 shown, the housing 5 is formed by coaxial stacking of kovar flanges, ceramics, and kovar flanges through welding in a hydrogen furnace. The welding seam of the housing 5 has vacuum tightness. The housing 5 has a structure of ceramic-kovar welding, ensuring the reliability of welding, vacuum tightness, and high-voltage insulation performance.

[0026] As Figure 1 and Figure 2As shown in the figure, the adjusting mechanism includes a first disc 8, a second disc 9, and an adjusting bolt 10 connecting the first disc 8 and the second disc 9. The adjusting bolt 10 is in contact with the kovar part 501. A plurality of adjusting bolts 10 are provided, and all the adjusting bolts 10 are evenly distributed circumferentially with the axis of the first disc 8 and the second disc 9 as the center line. The adjusting bolt 10 is threadedly connected to the first disc 8 and the second disc 9. The first disc 8, the second disc 9, the outer shell 5, and the sleeve are coaxially arranged. The kovar part 501 receives the pressure applied by the adjusting bolt 10, and each adjusting bolt 10 can apply pressure to the kovar part 501 at different positions of the kovar part 501. The sleeve 4 passes through the first disc 8 and the second disc 9 in sequence, and the sleeve 4 extends to the outside of the outer shell 5. The first disc 8 is fixedly connected to the end of the outer shell 5, and the second disc 9 is fixedly connected to the sleeve.

[0027] By turning the adjusting bolt 10 on the disc on the rear gun shell of the cathode assembly 1, the displacement of the cathode assembly 1 relative to the outer shell 5 can be adjusted. In the klystron electron optical system, it will cause changes in the distance between the electron beam and the anode and the channel, the incident angle, etc.

[0028] In this embodiment, four adjusting bolts 10 are provided, and all the adjusting bolts 10 are evenly distributed circumferentially. The kovar part 501 is arranged on the outer shell 5 by brazing. The kovar part 501 is located between the first disc 8 and the second disc 9. By rotating the four adjusting bolts 10, the distance between the first disc 8 and the second disc 9 can be changed in four directions. The relative position between the front end of the outer shell 5 and the first disc 8 is fixed, and the relative position between the cathode assembly 1 and the second disc 9 is fixed. When the distance between the first disc 8 and the second disc 9 changes, even if the distance between the cathode assembly 1 and the front end of the outer shell 6 changes. By adjusting the different distances in four directions by the four adjusting bolts 10, the distance, included angle and other position relationships between the cathode assembly 1 and the front end of the outer shell 5 can be finely adjusted as needed. In the klystron electron optical system, it will cause changes in the distance between the electron beam emitted by the electron gun and the anode and the channel, the incident angle, etc., so as to realize the dynamic adjustment of the electron circulation rate.

[0029] Preferably, the materials of the first disc 8 and the second disc 9 are stainless steel, and the first disc 8 and the second disc 9 have better structural strength and can well support the torque of the bolt turning.

[0030] Preferably, the cathode assembly 1 adopts a 10mm reserve type barium tungsten cathode, and the emission current density during operation is low. The emission current density of the cathode assembly 1 during operation is 1.2A / cm 2 .

[0031] Preferably, the front end of the outer shell 5 is welded to the slow-wave end cap by argon arc welding. The rear end of the sleeve 4 leads out the electrode lead 7 through the insulating terminal assembly 6. The insulating terminal assembly 6 is hermetically welded to the sleeve 4 by argon arc welding. The electrode lead 7 passes through the sleeve 4 and the insulating terminal assembly 6 in sequence. The insulating terminal assembly 6 is made by welding kovar and ceramics to ensure vacuum tightness and insulation performance.

[0032] Preferably, the focusing electrode 2 is made of oxygen-free copper material.

[0033] Preferably, the kovar part 501 is U-shaped. The kovar part 501 is processed by spinning to ensure excellent vacuum tightness and anti-bending fatigue toughness.

[0034] For the above-mentioned cathode-controlled electron gun structure, the reserve-type barium tungsten cathode is adopted. During operation, the emission current density is low, so the electron gun can be excited for a longer time and has the advantage of a long service life. The electron gun has a simple structure. The ceramic parts have higher anti-vibration ability, have the advantage of high reliability, and have the advantage of being able to dynamically adjust the electron flow rate, and are suitable for klystron products.

[0035] The assembly process of the above-mentioned cathode-controlled electron gun structure is as follows:

[0036] 1) Position the cathode assembly 1 and the focusing electrode 2 through a tooling and install them on the sleeve 4. By using the method of laser welding, the cathode assembly 1 and the focusing electrode 2 are sequentially welded and fixed to the sleeve 4, and the electrode lead 7 between the cathode assembly 1 and the filament is welded well to form the first assembly.

[0037] 2) Install the first assembly obtained in the previous step into the outer shell 5. Install the medium-low temperature solder wire at the induction heating welding and sealing position. According to the position requirements of the focusing electrode 2 and the outer shell 5 by assembling to the tooling, put the assembled component into the induction heating equipment, heat the induction heating welding and sealing position to melt the solder, and ensure vacuum tight welding to form the second assembly.

[0038] 3) Put the second assembly obtained above into the argon arc welding furnace and weld the position by argon arc welding to ensure a vacuum tight weld.

[0039] 4) Install the second disc 9 on the step at the tail end of the outer shell 5 and connect the second disc 9 and the first disc 8 together with the adjusting bolt 10.

[0040] 5) The welded electron gun can be connected to the klystron through the kovar flange at the front end of the outer shell 5 and vacuum sealed by argon arc welding.

[0041] The present invention has been described by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited by the above methods. As long as various non-substantive improvements are made by adopting the method concept and technical solution of the present invention; or without improvement, the above concept and technical solution of the present invention are directly applied to other occasions, they are all within the protection scope of the present invention.

Claims

1. The cathode-controlled electron gun structure for a klystron, including a housing, is characterized in that: It further includes a cathode assembly and a focusing electrode disposed within the housing. The focusing electrode is connected to the cathode assembly through a sleeve. A kovar part is provided inside the housing, and an adjusting mechanism for applying pressure to the kovar part is provided on the housing. The kovar part is configured to deform when subjected to the pressure applied by the adjusting mechanism, causing a change in the relative positions of the cathode assembly and the focusing electrode with respect to the housing.

2. The cathode-controlled electron gun structure for a klystron according to claim 1, characterized in that: The adjusting mechanism includes a first disc, a second disc disposed opposite to the first disc, and an adjusting bolt connecting the first disc and the second disc. The adjusting bolt is in contact with the kovar part.

3. The cathode-controlled electron gun structure for a klystron according to claim 2, characterized in that: A plurality of the adjusting bolts are provided, and all the adjusting bolts are evenly distributed circumferentially.

4. The cathode-controlled electron gun structure for a klystron according to claim 2, wherein: Four adjusting bolts are provided, and all the adjusting bolts are evenly distributed circumferentially.

5. The cathode-controlled electron gun structure for a klystron according to any one of claims 1 to 4, characterized in that: The sleeve is made of cupronickel, and the sleeve, the focusing electrode and the cathode assembly are fixedly connected together by laser welding.

6. The cathode-controlled electron gun structure for a klystron according to any one of claims 1 to 4, characterized in that: The cathode assembly uses a 10-mm reserve-type barium-tungsten cathode, and the emission current density during the operation of the cathode assembly is 1.2 A / cm 2 .

7. The cathode-controlled electron gun structure for a klystron according to any one of claims 1 to 4, characterized in that: The front end of the housing is welded to the slow-wave end cover by argon arc welding. The rear end of the sleeve leads out an electrode lead through an insulating terminal assembly, and the insulating terminal assembly is hermetically welded to the sleeve by argon arc welding.

8. The cathode-controlled electron gun structure for a klystron according to any one of claims 1 to 4, characterized in that: The focusing electrode is made of oxygen-free copper material.

9. The cathode-controlled electron gun structure for a klystron according to any one of claims 1 to 4, characterized in that: The kovar part is U-shaped and is processed by a spinning method.

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