Cathode assembly of X-ray tube
By designing the conductive ring body and arc-shaped slope in the cathode assembly of the X-ray tube, combined with the insulated isolation member, the problems of high cathode field strength and poor electronic focus performance are solved, and the reduction of electron escape and the improvement of focus performance are achieved.
Patent Information
- Application Number
- CN202411854838.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-03-28
AI Technical Summary
The cathode assembly of existing X-ray tubes is prone to cause electron dissipation at high voltages, damage the devices in the tube, and poor electronic focusing performance.
A cathode assembly of an X-ray tube is designed, including a cathode seat and a conductive ring body. The conductive ring body is sleeved outside the cathode seat. By setting an arcuate slope and an insulating isolation member, the cathode field strength is reduced, electron dissipation is reduced, and electron focus performance is improved.
It effectively reduces the cathode field strength, reduces the escape of electrons, improves the electron focusing performance, and extends the service life of the X-ray tube.
Smart Images
Figure CN119725053A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of X-ray tube manufacturing, and in particular to a cathode assembly of an X-ray tube. Background Art
[0002] Medical X-ray diagnostic equipment, such as computed tomography (CT), uses an X-ray tube assembly for X-ray photography. The X-ray tube assembly includes a housing and an X-ray tube. The X-ray tube is housed in the housing and radiates X-rays. The housing is provided with an X-ray radiation window for X-rays to pass through, and lead plates are adhered to other parts of the inner wall of the housing to shield X-rays.
[0003] An X-ray tube consists of a cathode, an anode target, and a vacuum envelope. The cathode and anode target face each other and are offset relative to the anode's axis of rotation. Within the vacuum created by the envelope, when a high voltage is applied between the cathode and anode target, the cathode emits electrons, which are accelerated to the anode and collide with the target surface. The anode target then radiates X-rays, which are then emitted through a window in the envelope.
[0004] As an electron emission device, the cathode system provides and maintains a stable tube current, which is one of the key technologies. The escape of electrons and secondary electrons will cause damage to the devices inside the tube. Summary of the Invention
[0005] To overcome the above-mentioned deficiencies of the prior art, the present invention provides a cathode assembly for an X-ray tube, which is beneficial for reducing cathode field strength, reducing electron dispersion, and improving electron focusing performance.
[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions: A cathode assembly of an X-ray tube, comprising: A cathode seat, wherein a filament slot is provided on the front side of the cathode seat, and a filament is provided in the filament slot; The conductive ring body is sleeved outside the cathode seat, the cathode seat is arranged in the inner circle of the conductive ring body, the height difference between the front end of the conductive ring body and the front end of the cathode seat is less than or equal to 3mm, and the conductive ring body is connected to the cathode seat.
[0007] It should be noted that, in this application, the end of the cathode assembly facing the anode target disk is defined as the front end, that is, the direction in which the filament emits electrons is the forward direction.
[0008] Furthermore, in an X-ray tube cathode assembly according to the present application, the width of the conductive ring is in the range of 2-10 mm, and the outer edge contour of the cathode base is adapted to the inner ring shape of the conductive ring, that is, the outer edge contour of the cathode base is circular. Therefore, the outer diameter of the conductive ring is 4-20 mm larger than the diameter of the cathode base. As a preferred embodiment of the present application, this embodiment can ensure the effect of reducing the cathode field strength.
[0009] Furthermore, in the cathode assembly of an X-ray tube in the present application, the material of the conductive ring includes at least one of iron-nickel alloy, iron-cobalt-nickel alloy, molybdenum and molybdenum alloy.
[0010] Furthermore, in the present application, a cathode assembly of an X-ray tube is provided with a first curved slope on the conductive ring body, the first curved slope being arranged at the front outer edge of the conductive ring body and being a circular curved surface. As a preferred embodiment of the present application, based on the above structure, the cathode field strength can be effectively reduced.
[0011] Furthermore, in the cathode assembly of an X-ray tube in the present application, a second arc-shaped slope is provided on the conductive ring body, and the second arc-shaped slope is arranged at the outer edge of the rear end of the conductive ring body, and the second arc-shaped slope is a circular curved surface.
[0012] Furthermore, in the cathode assembly of an X-ray tube disclosed herein, a pair of baffles are provided at both ends of the filament extending within the filament slot. The baffles are connected to the cathode holder, and the filament is disposed behind the front end of the baffles. A pair of protrusions extend from the front end of the cathode holder, and the baffle and filament slot are disposed between the pair of protrusions. As a preferred embodiment of the present invention, this structure facilitates the focusing of emitted electrons.
[0013] Furthermore, in the cathode assembly of an X-ray tube in the present application, the filament slot passes through the cathode seat in the extension direction, the filament slot is formed by wire cutting, and after the filament slot is processed, the baffle is connected to the cathode seat by welding or riveting. As a preferred embodiment of the present application, if the baffle and the cathode seat are integrally processed, the filament slot can only be set between a pair of baffles, and only tool cutting can be used during processing, which will have the following negative effects: on the one hand, the roughness of the filament slot after processing is difficult to guarantee; on the other hand, burrs are easily generated on the edge of the filament slot or the edge is chamfered, which will increase the risk of sparks or affect the size of the focus during use. In the present application, the above-mentioned process is adopted to avoid the negative effects caused by tool cutting.
[0014] Furthermore, in an X-ray tube cathode assembly of the present application, the height difference between the front end of the baffle and the front end of the filament ranges from 0.2 to 5 mm, and the distance between the end of the filament and the inner wall of the baffle adjacent thereto in the direction in which the filament slot extends is less than or equal to 5 mm. This is a preferred embodiment of the present application to optimize the focusing effect of electrons.
[0015] Furthermore, in the cathode assembly of an X-ray tube in the present application, an insulating spacer is connected to the cathode base; The number of filaments is 2, and a pair of pins is provided on the filament, wherein the pair of pins includes a first pin electrically connected to the cathode seat and a second pin insulated from the cathode seat. The insulating spacer is used for insulating and isolating the cathode base and the pair of second pins.
[0016] It can be seen from the above technical solution that the present invention has the following beneficial effects: 1. The present invention provides a cathode assembly for an X-ray tube. A conductive ring is provided on the periphery of the cathode base, which is beneficial for reducing the cathode field strength, reducing electron dispersion, and improving electron focusing performance.
[0017] 2. The present invention provides a cathode assembly for an X-ray tube, in which a baffle and a convex portion are arranged in front of a filament slot, which is beneficial to focusing the emitted electrons.
[0018] 3. The present invention provides a cathode assembly for an X-ray tube, in which the second pins of two filaments share a common insulating spacer. Compared with the traditional method of providing an insulating spacer for each second pin, this can withstand higher thermal stress, reduce the risk of cracking, and improve space compactness. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 Schematic diagram of the three-dimensional structure of a cathode assembly of an X-ray tube in an embodiment of the present application; Figure 2 is a cross-sectional view of a cathode assembly of an X-ray tube in an embodiment of the present application; Figure 3 is a schematic diagram of a conductive ring in an embodiment of the present application; Figure 4 Schematic diagram of the rear side structure of a cathode assembly of an X-ray tube in an embodiment of the present application.
[0020] In the figure: 1- cathode seat; 11- filament slot; 12- protrusion; 2- filament; 3- conductive ring; 31- first arc-shaped slope; 32- second arc-shaped slope; 4- baffle; 51- first pin; 52- second pin; 6- insulating spacer; DETAILED DESCRIPTION
[0021] Example 1 Combine Figures 1 to 3 As shown, this embodiment provides a cathode assembly of an X-ray tube, including: A cathode base 1 is provided with a filament slot 11 on the front side of the cathode base 1, and a filament 2 is provided in the filament slot 11; The conductive ring body 3 is sleeved on the outside of the cathode seat 1, and the cathode seat 1 is arranged in the inner circle of the conductive ring body 3. The height difference between the front end of the conductive ring body 3 and the front end of the cathode seat 1 is less than or equal to 3mm, and the conductive ring body 3 is connected to the cathode seat 1.
[0022] Based on the above structure, during operation, filament 2 is heated and emits electrons. A voltage is applied between cathode holder 1 and anode target (not shown) to accelerate the electrons. The provision of conductive ring 3 helps reduce cathode field strength, minimize electron escape, and improve electron focusing performance. Specifically, conductive ring 3 can be threaded or welded to cathode holder 1.
[0023] In this embodiment, the width of the conductive ring 3 is in the range of 2-10 mm, and the outer edge contour of the cathode base 1 is adapted to the inner ring shape of the conductive ring 3, that is, the outer edge contour of the cathode base 1 is circular. Therefore, the outer diameter of the conductive ring 3 is 4-20 mm larger than the diameter of the cathode base 1, which can ensure the effect of reducing the cathode field strength.
[0024] In this embodiment, the material of the conductive ring body 3 includes at least one of iron-nickel alloy, iron-cobalt-nickel alloy, molybdenum and molybdenum alloy.
[0025] In this embodiment, a first curved slope 31 is provided on the conductive ring body 3, and the first curved slope 31 is arranged at the front outer edge of the conductive ring body 3, and the first curved slope 31 is a circular curved surface. In this embodiment, the busbar corresponding to the first curved slope 31 is in the shape of a circular arc with a radius greater than 2 mm. That is, in this embodiment, the first curved slope 31 is a fillet with a radius greater than 2 mm. In other embodiments, the first curved slope 31 can be a curved surface with a non-standard fillet. In this embodiment, a second curved slope 32 is provided on the conductive ring body 3, and the second curved slope 32 is arranged at the rear outer edge of the conductive ring body 3, and the second curved slope 32 is a circular curved surface; the busbar corresponding to the second curved slope 32 is in the shape of a circular arc with a radius greater than 1.5 mm. The above-mentioned size and shape limitations are all optimized designs for the conductive ring body 3 to effectively reduce the cathode field strength.
[0026] Example 2 In this embodiment, based on Example 1, a pair of baffles 4 are provided at both ends of the filament 2 extending within the filament slot 11. The baffles 4 are connected to the cathode holder 1, and the filament 2 is disposed behind the front end of the baffles 4. A pair of protrusions 12 extend from the front end of the cathode holder 1, with the baffles 4 and the filament slot 11 disposed between the pair of protrusions 12. This structure facilitates the focusing of emitted electrons. It should be noted that the protrusions 12 are located at the front end of the cathode holder 1, and the front end of the protrusions 12 corresponds to the front end of the cathode holder 1.
[0027] In this embodiment, the filament slot 11 extends through the cathode holder 1 in the extension direction. The filament slot 11 is formed by wire cutting. After the filament slot 11 is processed, the baffle 4 is connected to the cathode holder 1 by welding or riveting. If the baffle 4 and the cathode holder 1 are integrally formed, the filament slot 11 can only be set between a pair of baffles 4, and can only be processed by tool cutting, which will have the following negative effects: on the one hand, the roughness of the filament slot 11 after processing is difficult to guarantee; on the other hand, the edge of the filament slot 11 is prone to burrs or chamfers, which will increase the risk of sparks or affect the size of the focus during use. In this application, the above process is adopted to avoid the negative effects caused by tool cutting.
[0028] In this embodiment, the height difference between the front end of the baffle 4 and the front end of the filament 2 ranges from 0.2 to 5 mm. The distance between the end of the filament 2 and the adjacent inner wall of the baffle 4 in the direction of extension of the filament slot 11 is less than or equal to 5 mm. It should be noted that the above situation includes both the case where the end of the filament 2 is on the inside and outside of the inner wall of the baffle 4, to optimize the electron focusing effect.
[0029] Example 3 Combine Figure 1 、 Figure 2 and Figure 4 As shown, based on Example 2, in this embodiment, An insulating spacer 6 is connected to the cathode seat 1; the number of filaments 2 is 2, and a pair of pins is provided on the filament 2, the pair of pins including a first pin 51 electrically connected to the cathode seat 1 and a second pin 52 insulated and isolated from the cathode seat 1, and the insulating spacer 6 is used to insulate and isolate the cathode seat 1 and the pair of second pins 52. Specifically, the pin is provided through the cathode seat 1 and extends from the rear end of the cathode seat 1, the insulating spacer 6 is provided between the cathode seat 1 and the second pin 52, and the pair of second pins 52 is provided through the insulating spacer 6. Compared with the traditional method of providing an insulating spacer 6 for each second pin 52, the use of an integral insulating spacer 6 can withstand higher thermal stress, reduce the risk of cracking, and improve the compactness of the space. Specifically, the insulating spacer 6 is made of ceramic, and the first pin 51 and the cathode seat 1, and the second pin 52 and the insulating spacer 6 are connected by welding.
[0030] The technical principles of the present invention have been described above in conjunction with specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will be able to conceive of other specific embodiments of the present invention without inventive effort, and such embodiments will fall within the scope of protection of the present invention.
Claims
1. A cathode assembly of an X-ray tube, characterized in that: include: A cathode seat (1), wherein a filament groove (11) is provided on the front side of the cathode seat (1), and a filament (2) is provided in the filament groove (11); A conductive ring body (3), the conductive ring body (3) is sleeved outside the cathode seat (1), the cathode seat (1) is arranged in the inner ring of the conductive ring body (3), the height difference between the front end of the conductive ring body (3) and the front end of the cathode seat (1) is less than or equal to 3 mm, and the conductive ring body (3) is connected to the cathode seat (1).
2. The cathode assembly of an X-ray tube according to claim 1, characterized in that: The width of the conductive ring body (3) is in the range of 2-10 mm, and the outer edge profile of the cathode seat (1) is adapted to the inner ring shape of the conductive ring body (3).
3. The cathode assembly of an X-ray tube according to claim 1, characterized in that: The material of the conductive ring body (3) comprises at least one of an iron-nickel alloy, an iron-cobalt-nickel alloy, molybdenum and a molybdenum alloy.
4. The cathode assembly of an X-ray tube according to claim 1, characterized in that: The conductive ring body (3) is provided with a first arc-shaped slope surface (31), the first arc-shaped slope surface (31) is arranged at the front end outer edge of the conductive ring body (3), and the first arc-shaped slope surface (31) is a circular curved surface.
5. The cathode assembly of an X-ray tube according to claim 4, characterized in that: The generatrix corresponding to the first arc-shaped slope surface (31) is in the shape of an arc with a radius greater than 2 mm.
6. The cathode assembly of an X-ray tube according to claim 4, characterized in that: The conductive ring body (3) is provided with a second arc-shaped slope surface (32), the second arc-shaped slope surface (32) being arranged at the outer edge of the rear end of the conductive ring body (3), the second arc-shaped slope surface (32) being a circular curved surface; the busbar corresponding to the second arc-shaped slope surface (32) being in the shape of an arc with a radius greater than 1.5 mm.
7. The cathode assembly of an X-ray tube according to claim 1, characterized in that: The filament (2) is provided with a pair of baffles (4) at both ends of the extension direction in the filament slot (11); the baffles (4) are connected to the cathode seat (1); the filament (2) is arranged at the rear side of the front end of the baffle (4); a pair of convex portions (12) extend from the front side of the cathode seat (1); the baffles (4) and the filament slot (11) are arranged between the pair of convex portions (12).
8. The cathode assembly of an X-ray tube according to claim 7, characterized in that: The filament slot (11) passes through the cathode seat (1) in the extension direction. The filament slot (11) is formed by wire cutting. After the filament slot (11) is processed, the baffle (4) is connected to the cathode seat (1) by welding or riveting.
9. The cathode assembly of an X-ray tube according to claim 7, characterized in that: The height difference between the front end of the baffle (4) and the front end of the filament (2) is in the range of 0.2-5 mm; the distance between the end of the filament (2) and the inner wall of the baffle (4) on the adjacent side in the extension direction of the filament slot (11) is less than or equal to 5 mm.
10. The cathode assembly of an X-ray tube according to claim 1, characterized in that: An insulating spacer (6) is connected to the cathode seat (1); The number of the filaments (2) is 2, and the filaments (2) are provided with a pair of pins, the pair of pins comprising a first pin (51) electrically connected to the cathode seat (1) and a second pin (52) insulated and isolated from the cathode seat (1). The insulating spacer (6) is used to insulate and isolate the cathode seat (1) and the pair of second pins (52).