Electron gun for traveling wave tube and traveling wave tube

Abstract

The invention provides an electron gun for a traveling wave tube and the traveling wave tube. The electron gun comprises an anode piece; the focusing electrode piece is positioned in the anode piece; the insulating support piece is positioned between the anode piece and the focusing pole piece; the cathode piece is positioned in the focusing electrode piece; the inner insulating support is positioned between the cathode piece and the focusing pole piece and is used for relatively fixing the cathode piece and the focusing pole piece; the focusing pole piece comprises a radially-reduced inward-retracting structure; and the insulating supporting piece is fixed between the inner receiving structure and the anode piece, so that the electron gun can meet the requirement that a traveling wave tube with the working frequency range of more than 0.1 THz is more than 17kV in withstand voltage.

Description

Technical Field

[0001] The present invention relates to the field of microwave vacuum electronic technology, and more specifically to an electron gun for a traveling wave tube and a traveling wave tube. Background Art

[0002] Traveling wave tubes have the advantages of high frequency, high power, high efficiency, wide bandwidth and high gain, and are widely used in radars, satellites, electronic countermeasures, etc. For potential applications such as confidential communications and high-speed communications, higher-frequency traveling wave tubes are needed as technical support. The electron gun is a key component of this type of device, which is used to form an electron beam that meets the requirements of use. With the increasing number of types of traveling wave tubes, the existing electron gun structure has been unable to meet the use requirements of different types of traveling wave tubes. Summary of the invention

[0003] In view of the above problems, the present invention provides an electron gun for a traveling wave tube to solve the problem that the existing electron gun is difficult to meet the use requirements of different types of traveling wave tubes.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The present invention provides an electron gun for a traveling wave tube, comprising:

[0006] Anode parts;

[0007] a focusing pole piece located inside the anode piece;

[0008] an insulating support member located between the anode member and the focusing pole member;

[0009] a cathode member located inside the focusing pole member;

[0010] and an inner insulating support located between the cathode piece and the focusing pole piece for fixing the cathode piece and the focusing pole piece relatively;

[0011] The focusing pole piece includes a radially reduced inward structure;

[0012] The insulating support member is fixed between the retracted structure and the anode member so that the electron gun can meet the withstand voltage requirement of more than 17 kV for a traveling wave tube with an operating frequency range of more than 0.1 THz.

[0013] The preferred solution is that the cathode component includes a cathode head for accommodating the thermal subassembly and a reduced diameter portion radially reduced relative to the cathode head; the reduced diameter portion is connected to the cathode head and corresponds to the inward structural position of the focusing pole piece;

[0014] The focusing pole piece also includes a first structural part for accommodating the cathode head; the retracted structure is connected to the first structural part.

[0015] A preferred solution is that the inner side wall surface of the inner insulating support is fixed around the outer side wall surface of the reduced diameter portion, and the outer side wall surface of the inner insulating support is combined and fixed with the inner side wall surface of the retracted structure.

[0016] A preferred solution is that the inner side wall surface of the insulating support member is fixed around the outer side wall surface of the retracted structure, and the outer side wall surface of the insulating support member is combined and fixed with the inner side wall surface of the anode member.

[0017] Preferably, the outer diameter of the anode member ranges from 13.5 to 33.5 mm.

[0018] A preferred solution is that the insulating support is in the shape of a circular ring, with a ring width ranging from 3 to 10 mm and a thickness ranging from 3 to 10 mm.

[0019] A preferred solution is that the difference between the outer radius of the first structural portion and the outer radius of the retracted structure is in the range of 0.5-3 mm.

[0020] A preferred solution is that the focusing pole piece and the cathode piece are coaxially arranged, and the distance between the inner side wall of the focusing pole piece and the outer side wall of the cathode piece is 0.5-1.5 mm.

[0021] The present invention also provides a traveling wave tube, which comprises the electron gun as described above.

[0022] A preferred solution is that the operating frequency range of the traveling wave tube is above 0.1 THz, and the traveling wave tube also includes a slow-wave circuit, a collector, a uniform permanent magnet focusing system and a titanium pump. The electron gun, the slow-wave circuit, the collector and the titanium pump are arranged in sequence along the axial direction of the uniform permanent magnet focusing system, and the uniform permanent magnet focusing system is arranged around the electron gun, the slow-wave circuit and the outer side of the collector; the inner diameter size range of the uniform permanent magnet focusing system is 15-35 mm.

[0023] The beneficial effects of the present invention are:

[0024] The present invention can ensure that the outer diameter of the electron gun is smaller than the inner diameter of the uniform permanent magnet focusing system so that the electron gun can be well assembled into the uniform permanent magnet focusing system, while enabling the electron gun to have sufficient withstand voltage performance to meet the withstand voltage requirements of a traveling wave tube with an operating frequency band of more than 0.1 THz. Specifically, by forming a radially reduced inward structure on the focusing pole piece, and fixing the insulating support piece between the anode piece and the inward structure, the insulating support piece can have a sufficient size to improve the withstand voltage level of the electron gun without changing the magnetic field structure and magnetic field strength of the uniform permanent magnet focusing system of the traveling wave tube. Under the condition of the same outer diameter of the electron gun, compared with the existing electron gun, the withstand voltage value of the electron gun of the present invention can be increased by more than 2 times, thereby being able to meet the use requirements of the traveling wave tube with an operating frequency band of more than 0.1 THz for electron gun assembly and withstand voltage performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The specific implementation modes of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0026] Figure 1 It is a schematic diagram of the overall structure of an existing electron gun.

[0027] Figure 2 It is a schematic diagram of the overall structure of the electron gun of the present invention.

[0028] Figure 3 It is a schematic diagram of the coordination between the cathode component and the focusing electrode component of the present invention.

[0029] Figure 4 It is a schematic diagram of the structure of the traveling wave tube of the present invention. DETAILED DESCRIPTION

[0030] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0031] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0032] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.

[0033] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0034] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0035] For traveling wave tubes with a frequency band above 0.1THz, the transmission of high current density electron beams is very difficult due to the small electron beam channel. The use of a uniform permanent magnet focusing system can effectively constrain the electron beam, increase the flow rate of the electron beam, and ensure efficient transmission of the electron beam in the traveling wave tube. At this time, the electron gun needs to be placed in a uniform permanent magnet focusing magnetic field as a whole. In order to meet actual application requirements, control the weight of the magnet 4, and obtain a sufficiently large magnetic induction intensity (6000GS-9600GS), the inner diameter A of the magnet 4 needs to be maintained in the range of 15mm-35mm. Figure 1As shown, the existing electron gun includes an anode 101, a focusing pole 102, a cathode 103, a first insulating support 104 and a second insulating support 105. However, the existing electron gun is difficult to be directly placed in the uniform permanent magnetic focusing magnetic field due to the large outer diameter of the anode (usually larger than A). Although the simple overall reduction of the size of the electron gun can meet the coordination with the uniform permanent magnetic focusing magnetic field, it will cause the withstand voltage level of the electron gun to decrease and fail to meet the design requirements of the traveling wave tube with an operating frequency of more than 0.1 THz. More specifically, if an electron gun of existing size is selected, the inner diameter of the magnetic steel 4 needs to be correspondingly increased to adapt to the electron gun of existing size, which will cause the magnetic induction intensity obtained by the magnetic focusing system of the same weight to be weakened by 2000-3000 GS. Such magnetic induction intensity is more difficult for the electron beam of the traveling wave tube with an operating frequency of more than 0.1 THz. If the inner diameter of the magnetic steel 4 is increased, the weight of the magnetic focusing system that meets the magnetic induction intensity requirement will exceed the use requirement, or the magnetic induction intensity of the magnetic steel 4 that meets the weight requirement cannot meet the design requirement, so the inner diameter of the magnetic steel 4 is not allowed to be changed. Then at this time, the size of the electron gun must be changed as a whole, and the outer diameter of the electron gun must be reduced to a range smaller than the inner diameter A of the magnetic steel 4. However, there is a problem at this time. Since the electron gun is proportionally reduced as a whole, the size of the insulating support of the electron gun will be relatively small and does not meet the design requirements. This results in the electron gun's voltage resistance level being unable to meet the voltage resistance requirement of 17kV for traveling wave tubes with an operating frequency band above 0.1THz. Therefore, it is necessary to change the structure of the cathode assembly to ensure the size of the insulating support and thus ensure that the voltage resistance performance of the electron gun meets the requirements.

[0036] Based on the above description, the present invention provides an electron gun for a traveling wave tube, Figures 1 to 4As shown, the electron gun suitable for the traveling wave tube specifically comprises: an anode member 11, a focusing pole member 12 located inside the anode member 11, an insulating support member 13 located between the anode member 11 and the focusing pole member 12, a cathode member 14 located inside the focusing pole member 12, and an inner insulating support 15 located between the cathode member 14 and the focusing pole member 12 for relatively fixing the cathode member 14 and the focusing pole member 12. The focusing pole member 12 comprises a radially reduced inward structure 121, and the insulating support member 13 is fixed between the inward structure 121 and the anode member 11 so that the electron gun can meet the withstand voltage requirement of more than 17 kV for the traveling wave tube with an operating frequency range of more than 0.1 THz. It should be noted that the operating voltage of the traveling wave tube in the frequency band above 0.1THz is above 17kV, that is, the voltage of the cathode piece 14 is above 17kV; the voltage difference between the focusing pole piece 12 and the cathode piece 14 is above 0.3kV; the voltage difference between the anode piece 11 and the focusing pole piece 12 is also above 17kV. According to the above parameters, the electron gun structure of the present invention is designed. Specifically, when the outer diameter of the electron gun is determined based on the size of the uniform permanent magnet focusing magnetic field, the purpose of the present invention is to maintain the radial size of the insulating support 13, thereby only improving the structure of the cathode piece 14 and the focusing pole piece 12, and the size of the insulating support 13 is maintained to ensure that the withstand voltage level between the focusing pole piece 12 and the anode piece 11 meets the requirements, that is, the withstand voltage of the electron gun of the present invention is greater than 17kV.

[0037] In the above embodiment, the cathode piece 14 includes a reduced diameter portion 141 corresponding to the retracted structure 121 of the focusing pole piece 12; the reduced diameter portion 141 is radially reduced relative to the cathode head 142; the reduced diameter portion 141 is connected to the cathode head 142 and corresponds to the position of the retracted structure 121 of the focusing pole piece 12; the inner side wall surface of the inner insulating support 15 is fixed around the outer side wall surface of the reduced diameter portion 141, and the outer side wall surface of the inner insulating support 15 is combined and fixed with the inner side wall surface of the retracted structure 121.

[0038] Further, the inner wall surface of the insulating support member 13 is fixed around the outer wall surface of the retracted structure 121, and the outer wall surface of the insulating support member 13 is fixedly combined with the inner wall surface of the anode member 11. In order to be assembled with the uniform permanent magnet focusing system, the outer diameter of the anode member 11 ranges from 13.5 mm to 33.5 mm, which is smaller than the inner diameter A of the uniform permanent magnet focusing system.

[0039] To ensure the voltage withstand requirement for the operation of the traveling wave tube, the insulating support member 13 is in a circular ring shape, with the ring width B dimension ranging from 3 to 10 mm and the thickness E dimension in the vertical direction ranging from 3 to 10 mm. Generally, the voltage withstand level of the insulating support member in a vacuum environment is 10 kV / mm. In actual operation, the voltage difference between the focusing electrode member 12 and the anode member 11 is above 17 kV. Since the ring width of the insulating support member 13 is the key factor determining the voltage withstand level of the electron gun, the ring width of the insulating support member 13 needs to be maintained within 3 mm - 10 mm. If the ring width becomes smaller, the voltage withstand level of the electron gun will be reduced to 8 - 10 kV, no longer meeting the working voltage requirements of the traveling wave tube above 0.1 THz.

[0040] The cathode member 14 includes a cathode head 142 for accommodating the heater sub - assembly 18; the reduced - diameter portion 141 is in communication with the cathode head 142; the reduced - diameter portion 141 and the cathode head 142 are welded by laser welding in cooperation with the corresponding stepped portion 16. The focusing electrode member 12 further includes a first structural portion 122 for accommodating the cathode head 142; the inward - converging structure 121 is in communication with the first structural portion 122. The inward - converging structure 121 and the first structural portion 122 are welded by laser welding in cooperation with the corresponding stepped portion 16. During the actual tube manufacturing process, due to the requirements of the heater and related processes and dimensions for the operation and heat generation of the cathode member 14, the dimensions of the cathode member 14 for accommodating this part cannot be changed arbitrarily. At the same time, to ensure that the ring width dimension of the insulating support member 13 remains unchanged, the lower part of the cathode member 14 together with the lower part of the focusing electrode member 12 needs to be reduced in size synchronously. The purpose of such a setting is to ensure the normal operation of the cathode member 14 while also meeting the required voltage withstand level between the focusing electrode member 12 and the anode member 11.

[0041] It can be understood that reducing the cathode member 14 and the focusing electrode member 12 has no impact on other performance of the electron gun. However, due to the existence of the heater sub - assembly 18, the cathode member 14 cannot be directly reduced proportionally as a whole. The size of the cathode head 142 needs to be kept fixed. The present invention solves this problem by reducing the lower - part structure of the cathode member 14 and the focusing electrode member 12. That is to say, to ensure that the outer diameter of the electron gun is within the range of 13.5 - 33.5 mm and at the same time ensure that the insulating support member 13 has sufficient voltage withstand, and the size of the heater sub - assembly 18 inside the cathode member 14 corresponds to the overall size of the electron gun and cannot be changed independently. Then the length C and width D of the cathode head 142 are certain, 10 mm ≤ C ≤ 15 mm, 4 mm < D < 8 mm. Therefore, an improved diameter - reduction type is made for the part of the cathode member 14 below the length C of the cathode member 14 to form a reduced - diameter portion 141, and a corresponding inward - converging structure 121 is formed on the focusing electrode member 12. For the convenience of assembly, the two parts of the cathode member 14 and the focusing electrode member 12 with unequal upper and lower diameters are separated and finally welded and fixed respectively by laser welding.

[0042] In order to match the size of the insulating support 13 , the difference F between the outer radius of the first structure portion 122 and the outer radius of the retracted structure 121 is in the range of 0.5-3 mm.

[0043] In order to ensure that there is enough pressure difference between the focusing pole piece 12 and the cathode piece 14 in the vacuum atmosphere, the focusing pole piece 12 and the cathode piece 14 are coaxially arranged, and the distance G between the inner wall of the focusing pole piece 12 and the outer wall of the cathode piece 14 is 0.5-1.5mm. An assembly step 17 is formed on the inner wall surface of the anode piece 11 to match the outer wall surface of the insulating support piece 13 and is connected by brazing, which has strong versatility.

[0044] The present invention also provides a traveling wave tube, which comprises the electron gun 1 as described above.

[0045] Further, the operating frequency range of the traveling wave tube is above 0.1 THz, and the traveling wave tube also includes a slow wave circuit 2, a collector 3, a uniform permanent magnet focusing system and a titanium pump 5. The electron gun 1, the slow wave circuit 2, the collector 3 and the titanium pump 5 are arranged in sequence along the axial direction of the uniform permanent magnet focusing system, and the uniform permanent magnet focusing system is arranged around the electron gun 1, the slow wave circuit 2 and the outer side of the collector 3. It can be understood that the function of the titanium pump 5 is to maintain the vacuum atmosphere of the traveling wave tube. The uniform permanent magnet focusing system includes an annular magnetic steel 4, and the inner diameter A of the annular magnetic steel 4 ranges from 15 mm to 35 mm.

[0046] Compared with the existing technical solutions, the technical solution of the present invention reduces the outer diameter of the electron gun to be smaller than the inner diameter A of the magnet 4 of the uniform permanent magnetic focusing system, which can ensure that the uniform permanent magnetic focusing system can be matched with the electron gun without changing the weight and magnetic induction intensity. In order for the electron gun to meet the required voltage resistance level of the design, the size of the insulating support 13 must be guaranteed. In the case where the outer diameter of the electron gun is determined to be reduced, if the sizes of the three electrodes are proportionally reduced, it is bound to lead to a reduction in the ring width B of the insulating support 13. However, B is a key factor in determining the voltage resistance level of the electron gun and a key factor in the normal operation of the traveling wave tube. Therefore, it is necessary to keep B unchanged, and then it is necessary to change the structural features of the cathode member 14 and the focusing pole member 12. The present invention reduces the diameter of the lower structure of the cathode member 14 and the focusing pole member 12 so that there is enough space between the anode member 11 and the focusing pole member 12 to ensure that the ring width B does not decrease as the outer diameter of the electron gun decreases. The electron gun structure can meet all traveling wave tubes that need to adopt a uniform permanent magnetic focusing system, and can be extended to all traveling wave tubes that need miniaturized electron guns. The measured withstand voltage level of the electron gun provided by the present invention is greater than 30 kV, which can well meet the actual application requirements of the traveling wave tube.

[0047] In summary, the present invention can ensure that the outer diameter of the electron gun is smaller than the inner diameter of the uniform permanent magnet focusing system to achieve good assembly of the electron gun into the uniform permanent magnet focusing system, while enabling the electron gun to have sufficient pressure resistance to meet the pressure resistance requirements of a traveling wave tube with an operating frequency band of more than 0.1 THz. Specifically, by reducing the diameter of part of the focusing pole piece to form an inward structure thereon, and fixing the insulating support piece between the anode piece and the inward structure, the insulating support piece can have a sufficient ring width to improve the pressure resistance level of the electron gun without changing the magnetic field structure and magnetic induction intensity of the uniform permanent magnet focusing system of the traveling wave tube. Under the condition of the same outer diameter size of the electron gun, compared with the existing electron gun, the pressure resistance value of the present invention can be increased by more than 2 times, thereby being able to meet the use requirements of the traveling wave tube with an operating frequency band of more than 0.1 THz for electron gun assembly and pressure resistance.

[0048] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. An electron gun for a traveling wave tube, characterized in that: include: Anode parts; a focusing pole piece located inside the anode piece; an insulating support member located between the anode member and the focusing pole member; a cathode member located inside the focusing pole member; and an inner insulating support located between the cathode piece and the focusing pole piece for fixing the cathode piece and the focusing pole piece relatively; The focusing pole piece includes a radially reduced inward structure; The insulating support member is fixed between the retracted structure and the anode member so that the electron gun can meet the withstand voltage requirement of more than 17 kV for a traveling wave tube with an operating frequency range of more than 0.1 THz.

2. The electron gun for a traveling wave tube according to claim 1, characterized in that: The cathode component includes a cathode head for accommodating the thermal subassembly and a reduced diameter portion radially reduced relative to the cathode head; the reduced diameter portion is connected to the cathode head and corresponds to the inward structural position of the focusing pole piece; The focusing pole piece also includes a first structural part for accommodating the cathode head; the retracted structure is connected to the first structural part.

3. The electron gun for a traveling wave tube according to claim 2, characterized in that: The inner side wall surface of the inner insulating support is fixed around the outer side wall surface of the reduced diameter portion, and the outer side wall surface of the inner insulating support is combined and fixed with the inner side wall surface of the retracted structure.

4. The electron gun for a traveling wave tube according to claim 1, characterized in that: The inner side wall surface of the insulating support member is fixed around the outer side wall surface of the retracted structure, and the outer side wall surface of the insulating support member is combined and fixed with the inner side wall surface of the anode member.

5. The electron gun for a traveling wave tube according to claim 1, characterized in that: The outer diameter of the anode member ranges from 13.5 to 33.5 mm.

6. The electron gun for a traveling wave tube according to claim 1, characterized in that: The insulating support is in the shape of a circular ring, with a ring width ranging from 3 to 10 mm and a thickness ranging from 3 to 10 mm.

7. The electron gun for a traveling wave tube according to claim 2, characterized in that: The difference between the outer radius of the first structure portion and the outer radius of the retracted structure is in the range of 0.5-3 mm.

8. The electron gun for a traveling wave tube according to claim 1, characterized in that: The focusing pole piece and the cathode piece are coaxially arranged, and the distance between the inner side wall of the focusing pole piece and the outer side wall of the cathode piece is 0.5-1.5 mm.

9. A traveling wave tube, characterized in that: The traveling wave tube comprises the electron gun as claimed in any one of claims 1-8.

10. The traveling wave tube according to claim 9, characterized in that: The operating frequency range of the traveling wave tube is above 0.1 THz. The traveling wave tube also includes a slow-wave circuit, a collector, a uniform permanent magnet focusing system and a titanium pump. The electron gun, the slow-wave circuit, the collector and the titanium pump are arranged in sequence along the axial direction of the uniform permanent magnet focusing system. The uniform permanent magnet focusing system is arranged around the electron gun, the slow-wave circuit and the outer side of the collector; the inner diameter size range of the uniform permanent magnet focusing system is 15-35 mm.

Images