Cathode assembly, X-ray tube, CT equipment and X-ray focus adjusting method

Abstract

The invention relates to a cathode assembly, an X-ray tube, CT equipment and an X-ray focus adjusting method. The cathode assembly comprises a flat cathode and a focusing electrode. The flat cathode comprises a plurality of cathode sheets, the plurality of cathode sheets are circumferentially arranged around the center of the flat cathode, and the included angle between the plurality of cathode sheets and the central axis of the flat cathode is an acute angle; each cathode plate can independently emit an electron beam; the focusing electrode is arranged on the periphery of the flat cathode in a surrounding manner; the focusing electrode is provided with a focusing surface, the included angle between the focusing surface and the central axis of the plate cathode is an acute angle, and the focusing electrode is used for focusing electron beams emitted by the plate cathode. The flat cathode comprises a plurality of cathode plates capable of independently emitting the electron beams, so that the cathode plates with different positions and numbers can be selectively selected to emit the electron beams, and the focus size and the focus position of the electron beams can be flexibly adjusted. And the whole plate cathode is similar to a Pearls structure electron beam, and is relatively good in laminar flow property and relatively good in uniformity.

Description

Technical Field

[0001] The present application relates to the field of X-ray technology, and in particular to a cathode assembly, an X-ray tube, a CT device, and an X-ray focus adjustment method. Background Art

[0002] X-ray technology is widely used in life, such as industrial non-destructive testing, safety inspection, medical diagnosis and treatment. However, the commonly used electric focusing structure of existing X-ray tubes often introduces nonlinear forces, which deteriorates the laminarity of the electron beam, thereby causing the electron beam spot on the target disk to deteriorate in uniformity, reducing the power of the X-ray tube and shortening the life of the target disk. In addition, in order to enhance the adjustment capability of the focal beam spot, existing X-ray tubes often introduce multiple focusing elements, which not only increases the cost of the X-ray tube but also increases the size of the X-ray tube. Summary of the invention

[0003] Based on this, it is necessary to provide an X-ray tube to address the problems of poor beam spot uniformity and insufficient beam spot size adjustment capability of the existing X-ray tube.

[0004] A cathode assembly comprising:

[0005] A flat cathode, the flat cathode comprising a plurality of cathode plates, the plurality of cathode plates being arranged circumferentially around the center of the flat cathode, the plurality of cathode plates being arranged at an acute angle to the central axis of the flat cathode; each of the cathode plates being capable of emitting an electron beam individually;

[0006] A focusing electrode is arranged around the outer periphery of the flat cathode; the focusing electrode has a focusing surface, the angle between the focusing surface and the central axis of the flat cathode is an acute angle, and the focusing electrode is used to focus the electron beam emitted by the flat cathode.

[0007] In one embodiment, the angle θ between the flat cathode and the central axis of the flat cathode is 1 Requirements:

[0008] 45°≤θ 1 ≤86°.

[0009] In one embodiment, the cathode assembly further comprises a base for mounting the flat cathode, the mounting surface shape of the base corresponds to the shape of the flat cathode, and the surface on the base for mounting the corresponding cathode sheet is parallel to the surface of the corresponding cathode sheet.

[0010] In one of the embodiments, a gap is provided between the flat cathode and the base.

[0011] In one embodiment, the shapes and sizes of the plurality of cathode plates are equal, and the plurality of cathode plates are arranged at equal angles along the circumference of the flat cathode.

[0012] In one embodiment, the angles between the plurality of cathode plates and the central axis of the flat cathode are all equal.

[0013] In one embodiment, a fixing area is provided between the plurality of cathode sheets, and the fixing area is used to fix and separate the cathode sheets.

[0014] In one embodiment, the fixed area is provided with current input bits and current output bits, the number of the current input bits and the current output bits are respectively equal to the number of the cathode sheets, and the current input bits and the current output bits are used to control the electron beam emission of the cathode sheet.

[0015] In one of the embodiments, the cathode assembly includes a grid, the grid and the focusing electrode are spaced apart along the central axis of the flat cathode, and the grid is used to adjust the intensity of the electron beam passing through the focusing electrode.

[0016] The present application also provides an X-ray tube that can solve at least one of the above technical problems.

[0017] The present application provides an X-ray tube, which includes the cathode assembly described in any one of the above embodiments, and also includes a magnetic focusing assembly, the magnetic focusing assembly includes at least one magnetic focusing device, and the magnetic focusing device includes a solenoid, a quadrupole magnet or a guide magnet.

[0018] In one of the embodiments, the X-ray tube includes a vacuum-enclosed shell, the vacuum-enclosed shell is configured with a beam channel, the beam channel is used to be arranged between the cathode assembly and the anode target plate, a magnetic focusing device is arranged outside the beam channel, and the length of the beam channel matches one of the magnetic focusing devices.

[0019] The present application also provides a CT device that can solve at least one of the above technical problems.

[0020] The present application provides a CT device, which includes the X-ray tube described in any one of the above embodiments.

[0021] The present application also provides an X-ray focus adjustment method, which can solve at least one of the above technical problems.

[0022] The present application provides an X-ray focus adjustment method, which uses the X-ray tube described in any one of the above embodiments; the X-ray focus adjustment method comprises:

[0023] Obtaining an operating mode of the X-ray tube;

[0024] Applying a preset current to the flat cathode according to the working mode to control one or more of the plurality of cathode plates of the flat cathode to selectively conduct and emit electron beams;

[0025] The working modes include a small focus mode in which a single cathode piece emits an electron beam and a large focus mode in which at least two cathode pieces emit an electron beam.

[0026] The cathode assembly, X-ray tube, CT device and X-ray focus adjustment method described above, since the flat cathode includes multiple cathode plates, and the multiple cathode plates can emit electron beams separately, the user can selectively select cathode plates of different positions and numbers to emit electron beams according to actual needs, thereby making the adjustment of the focus size and position of the electron beam more flexible, so that the treatment accuracy of the electron beam is higher and the treatment effect is better. At the same time, since the multiple cathode plates in the flat cathode of the present application are arranged at an acute angle with the central axis of the flat cathode, the entire flat cathode is similar to a Pierce structure, so that the laminarity and uniformity of the electron beam are better, and the electron beam is not easy to hit the outer wall of the tube during transmission, so that the tube wall of the tube is not easy to be damaged, and the service life of the tube and the entire X-ray tube is longer. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a cathode assembly provided by an embodiment of the present application being installed on an X-ray tube.

[0028] Figure 2 for Figure 1 A schematic diagram of a flat cathode of a cathode assembly in an X-ray tube is shown.

[0029] Figure 3 for Figure 1 Schematic diagram of the flat cathode, base and focusing electrode in the X-ray tube shown.

[0030] Figure 4 For power on Figure 2 The diagram is a schematic diagram of the first experimental result of a simulation experiment on the first cathode sheet in the cathode assembly shown.

[0031] Figure 5 For power on Figure 2 The diagram is a schematic diagram of the second experimental result of a simulation experiment on the first cathode plate and the third cathode plate of the cathode assembly.

[0032] Figure 6 For power on Figure 2 The third experimental result schematic diagram of the simulation experiment of the first cathode sheet, the second cathode sheet and the third cathode sheet in the cathode assembly is shown.

[0033] Figure 7 For power on Figure 2 The fourth experimental result schematic diagram of the simulation experiment of the first cathode sheet, the second cathode sheet, the third cathode sheet and the fourth cathode sheet in the cathode assembly is shown.

[0034] Figure numerals: 100-flat cathode; 110-cathode plate; 111-first cathode plate; 112-second cathode plate; 113-third cathode plate; 114-fourth cathode plate; 120-fixed area; 121-current input position; 122-current output position; 123-fixed position; 130-base; 131-mounting surface; 132-gap; 140-electron beam; 200-focusing electrode; 210-focusing surface; 300-magnetic focusing device; 400-vacuum closed shell; 410-beam channel; 500-anode target disk; 510-target disk edge; 520-rotation axis; 600-X-ray beam. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0036] In the description of the present application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application.

[0037] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0038] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0039] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0040] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only implementation method.

[0041] See also Figure 1-Figure 3 , Figure 1 A schematic diagram showing a cathode assembly provided by an embodiment of the present application being installed on an X-ray tube is shown. Figure 2 Shows Figure 1 A schematic diagram of a flat cathode 100 of a cathode assembly in an X-ray tube is shown. Figure 3 Shows Figure 1A schematic diagram of a flat cathode 100, a base 130 and a focusing electrode 200 in an X-ray tube is shown. A cathode assembly provided in an embodiment of the present application includes a flat cathode 100 and a focusing electrode 200. The flat cathode 100 includes a plurality of cathode sheets 110, which are arranged circumferentially around the center of the flat cathode 100, and the angles between the plurality of cathode sheets 110 and the central axis p of the flat cathode 100 are acute; each cathode sheet 110 can emit an electron beam 140 separately; the focusing electrode 200 is arranged around the periphery of the flat cathode 100; the focusing electrode 200 has a focusing plane 210, and the angle between the focusing plane 210 and the central axis p of the flat cathode 100 is acute, and the focusing electrode 200 is used to focus the electron beam 140 emitted by the flat cathode 100.

[0042] In the cathode assembly provided in the embodiment of the present application, since the flat cathode 100 includes a plurality of cathode sheets 110, and the plurality of cathode sheets 110 can emit electron beams 140 separately, the user can selectively select cathode sheets 110 of different positions and numbers to emit electron beams 140 according to actual needs, thereby making the adjustment of the focal size and position of the electron beam 140 more flexible, for example Figure 4-Figure 7 As shown, the beam spot size and beam spot position formed by the electron beam 140 emitted by the cathode pieces 110 at different positions and numbers are all different, so that the treatment accuracy of the electron beam 140 is higher and the treatment effect is better. At the same time, because the multiple cathode pieces 110 in the flat cathode 100 of the present application are arranged at an acute angle with the central axis p of the flat cathode 100, the entire flat cathode 100 is similar to a Pierce structure, so that the laminar flow of the electron beam 140 is better and the uniformity is better. The electron beam 140 is not easy to hit the outer wall of the tube during transmission, so that the tube wall of the tube is not easy to be damaged, and the service life of the tube and the entire X-ray tube is longer.

[0043] See also Figure 3 In one specific embodiment, the flat cathode 100 includes four cathode sheets 110, each cathode sheet 110 is fan-shaped, and the angle between the center circumference of the flat cathode 100 and each cathode sheet 110 is 90°. In another specific embodiment, the flat cathode 100 may also include three cathode sheets 110, five cathode sheets 110, or six cathode sheets 110, etc., without any special limitation.

[0044] The structure of the cathode assembly is described in detail below.

[0045] See also Figure 3 , the angle θ between the flat cathode 100 of the cathode assembly provided in some embodiments of the present application and the central axis p of the flat cathode 100 1 Satisfy the conditions: 45°≤θ 1≤86°. By setting θ 1 The angle is set to be greater than or equal to 45° and less than or equal to 86°, so that the entire flat cathode 100 forms a spherical structure, and the entire cathode assembly is a Pierce cathode gun that is approximately spherical, so that the focal spot uniformity of the electron beam 140 is better, thereby improving the life of the X-ray tube target disk.

[0046] In one specific embodiment, the angle θ between the flat cathode 100 and the central axis p of the flat cathode 100 is 1 is 45°.

[0047] In another specific embodiment, the angle θ between the flat cathode 100 and the central axis p of the flat cathode 100 is 1 It is 86°.

[0048] In another specific embodiment, the angle θ between the flat cathode 100 and the central axis p of the flat cathode 100 is 1 is 50°.

[0049] In yet another specific embodiment, the angle θ between the flat cathode 100 and the central axis p of the flat cathode 100 is 1 is 70°.

[0050] In some embodiments, the angle θ between the flat cathode 100 of the cathode assembly and the central axis p of the flat cathode 100 is 1 Satisfy the conditions: 60°≤θ 1 ≤80°. By setting θ 1 The angle is set to be greater than or equal to 60° and less than or equal to 80°, so that the entire flat cathode 100 forms a spherical structure, and the entire cathode assembly is a Pierce cathode gun that is approximately spherical, so that the focal spot uniformity of the electron beam 140 is better, thereby improving the life of the X-ray tube target disk.

[0051] In one specific embodiment, the angle θ between the flat cathode 100 and the central axis p of the flat cathode 100 is 1 is 60°.

[0052] In another specific embodiment, the angle θ between the flat cathode 100 and the central axis p of the flat cathode 100 is 1 is 80°.

[0053] In another specific embodiment, the angle θ between the flat cathode 100 and the central axis p of the flat cathode 100 is 1 is 65°.

[0054] In yet another specific embodiment, the angle θ between the flat cathode 100 and the central axis p of the flat cathode 100 is1 is 75°.

[0055] See also Figure 3 The cathode assembly provided in one embodiment of the present application further includes a base 130, and the base 130 is used to mount the flat cathode 100. The shape of the mounting surface 131 of the base 130 corresponds to the shape of the flat cathode 100, and the surface of the base 130 for mounting the corresponding cathode sheet 110 is parallel to the corresponding cathode sheet 110. By making the surface of the base 130 for mounting the corresponding cathode sheet 110 parallel to the surface of the corresponding cathode sheet 110, for example, when the surface of the cathode sheet 110 is a curved surface, the surface of the base 130 for mounting the corresponding cathode sheet 110 is also a curved surface. When the surface of the cathode sheet 110 is a plane, the surface of the base 130 for mounting the corresponding cathode sheet 110 is also a plane. Moreover, the shape of the mounting surface 131 of the base 130 corresponds to the shape of the flat cathode 100, so that the installation and fixation of each cathode plate 110 to the base 130 is relatively convenient, and at the same time, the installation angle of the cathode plate 110 relative to the central axis p of the flat cathode 100 can be effectively guaranteed, so that the installation error between the multiple cathode plates 110 is relatively small, thereby making the accuracy of the electron beam 140 finally emitted by the flat cathode 100 higher.

[0056] See also Figure 3 In one embodiment of the cathode assembly provided by the present application, a gap 132 is provided between the flat cathode 100 and the base 130. By providing the gap 132 between the flat cathode 100 and the base 130, the flat cathode 100 is easy to dissipate heat.

[0057] See also Figure 2 The cathode assembly provided in one embodiment of the present application has multiple cathode sheets 110 of equal size and shape, and the multiple cathode sheets 110 are arranged at equal angles along the circumference of the flat cathode 100. The multiple cathode sheets 110 are arranged to be equal in size and size, so that the electron beam 140 emitted by each cathode sheet 110 has the same size and shape, which makes it easier to accurately control the beam spot size and beam spot position of the emitted electron beam 140; at the same time, it can also make the structure of the entire flat cathode 100 more compact; and the processing and forming of the cathode sheet 110 is also more convenient. For details, please refer to Figure 3 In one embodiment, the flat cathode 100 includes four cathode plates 110 , each cathode plate 110 is disposed at an angle of 90° along the circumference of the flat cathode 100 .

[0058] In one embodiment, the angles between the plurality of cathode sheets 110 and the central axis p of the flat cathode 100 are all equal. By making the angles between the plurality of cathode sheets 110 and the central axis p of the flat cathode 100 all equal, the spherical structure of the flat cathode 100 formed by the plurality of cathode sheets 110 being arranged together is improved, and the entire cathode assembly is more likely to become a spherical Pierce cathode gun, so that the focal spot uniformity of the electron beam 140 is better, thereby improving the life of the target disk of the X-ray tube.

[0059] See also Figure 2 A fixing area 120 is provided between the multiple cathode sheets 110 of the cathode assembly provided in an embodiment of the present application, and the fixing area 120 is used to fix and separate the cathode sheets 110. By providing the fixing area 120, the cathode sheets 110 adjacent to each other can be separated and isolated, so that when a single cathode sheet 110 conducts current and emits an electron beam 140 independently, it is not easy for each other to affect each other.

[0060] See also Figure 2 The fixed area 120 of the cathode assembly provided in one embodiment of the present application is provided with a current input position 121 and a current output position 122, the number of which is equal to the number of the cathode sheets 110, and the current input position 121 and the current output position 122 are used to control the emission of the electron beam 140 of the cathode sheet 110. When the cathode sheet 110 is required to emit the electron beam 140, the current input position 121 and the current output position 122 are connected to an external power source, so that the external power source supplies power to the cathode sheet 110, so that the cathode sheet 110 emits the electron beam 140.

[0061] See also Figure 2 In one embodiment of the present application, a fixing position 123 is further provided on the fixing area 120 of the cathode assembly, and the fixing position 123 is used to fix the cathode sheet 110 on the fixing area 120 .

[0062] In one embodiment, the cathode assembly includes a grid, which is spaced apart from the focusing electrode 200 along the central axis p of the flat cathode 100, and the grid is used to adjust the intensity of the electron beam 140 passing through the focusing electrode 200. The intensity of the electron beam 140 is adjusted by the grid, so that the intensity of the electron beam 140 can meet the requirements of different usage conditions.

[0063] In one specific embodiment, a plane perpendicular to the central axis p of the planar cathode 100 is taken as a preset plane, and the orthographic projection of the focusing electrode 200 on the preset plane coincides with the orthographic projection of the gate on the preset plane.

[0064] See also Figure 2The cathode sheet 110 of the cathode assembly provided in one embodiment of the present application is in the shape of a sector, and the flat cathode 100 is in the shape of a circle. By setting the cathode sheet 110 in the shape of a sector, the flat cathode 100 formed by arranging a plurality of cathode sheets 110 in the circumferential direction around the center of the flat cathode 100 is a circular structure, and the entire flat cathode 100 forms a spherical structure, and the entire cathode assembly is a Pierce cathode gun that is approximately spherical, so that the focal spot uniformity of the electron beam 140 is better, so as to improve the life of the target disk of the X-ray tube.

[0065] See also Figure 1 The X-ray tube provided in one embodiment of the present application includes the cathode assembly described in any of the above embodiments, and also includes a magnetic focusing assembly, the magnetic focusing assembly includes at least one magnetic focusing device 300, and the magnetic focusing device 300 includes a solenoid, a quadrupole magnet, or a guide magnet. After the cathode assembly of the X-ray tube provided in the embodiment of the present application emits an electron beam 140, the magnetic focusing assembly can focus the electron beam 140, thereby making the laminar uniformity of the electron beam 140 that finally hits the anode target plate 500 better.

[0066] In one specific embodiment, the magnetic focusing component is a quadrupole magnet. In another specific embodiment, the magnetic focusing component is a solenoid. In another specific embodiment, the magnetic focusing component is a guide magnet. In yet another specific embodiment, the magnetic focusing component is a solenoid and a quadrupole magnet. It should be noted that the magnetic focusing component specifically includes one or more magnetic focusing devices 300, and whether the magnetic focusing device 300 is a solenoid, a quadrupole magnet or a guide magnet is not particularly limited, and it can be selected according to actual usage requirements.

[0067] It should be noted that in actual use, different focal spot sizes often correspond to different X-ray tube powers, large focal spots are matched with high power, and small focal spots are matched with low power. When a flat cathode 100 needs to meet both high power and low power, the flat cathode 100 temperature corresponding to the high power is higher, which will affect the service life of the flat cathode 100. Since the flat cathode 100 of the cathode assembly of the X-ray tube of the present application has multiple cathode pieces 110, and each cathode piece 110 can emit an electron beam 140 separately, it is possible to switch between multiple focal spot sizes in cooperation with the magnetic focusing device 300. When a large focal spot electron beam 140 is required, multiple cathode pieces 110 can be selected to simultaneously emit the electron beam 140, and when a small focal spot electron beam 140 is required, a single or a few cathode pieces 110 can be selected to emit the electron beam 140. This method can effectively ensure that the temperature of each cathode piece 110 is relatively low, thereby improving the service life of the flat cathode 100. Moreover, since the angles between the multiple cathode pieces 110 and the central axis p of the flat cathode 100 are arranged at an acute angle, the structure of the flat cathode 100 of the present X-ray tube is more compact, the adaptability to the focal spot size is stronger, and the function is more powerful.

[0068] See also Figure 1-Figure 3 The cathode assembly of an X-ray tube provided in an embodiment of the present application includes a flat cathode 100 and a focusing electrode 200. The flat cathode 100 includes a plurality of cathode plates 110, which are arranged circumferentially around the center of the flat cathode 100, and the angles between the plurality of cathode plates 110 and the central axis p of the flat cathode 100 are acute; each cathode plate 110 can emit an electron beam 140 separately; the focusing electrode 200 is arranged around the periphery of the flat cathode 100; the focusing electrode 200 has a focusing surface 210, and the angle between the focusing surface 210 and the central axis p of the flat cathode 100 is acute, and the focusing electrode 200 is used to focus the electron beam 140 emitted by the flat cathode 100.

[0069] Since the flat cathode 100 includes a plurality of cathode sheets 110, and the plurality of cathode sheets 110 can emit the electron beam 140 separately, the user can selectively select cathode sheets 110 of different positions and numbers to emit the electron beam 140 according to actual needs, thereby making the adjustment of the focal size and position of the electron beam 140 more flexible, for example Figure 4-Figure 7As shown, the beam spot size and beam spot position formed by the electron beam 140 emitted by the cathode pieces 110 at different positions and numbers are all different, so that the treatment accuracy of the electron beam 140 is higher and the treatment effect is better. At the same time, because the multiple cathode pieces 110 in the flat cathode 100 of the X-ray tube of the present application are arranged at an acute angle with the central axis p of the flat cathode 100, the entire flat cathode 100 is similar to a Pierce structure, so that the laminar flow of the electron beam 140 is better and the uniformity is better. The electron beam 140 is not easy to hit the outer wall of the tube during transmission, so that the tube wall of the tube is not easy to be damaged, and the service life of the tube and the entire X-ray tube is longer.

[0070] See also Figure 3 In one specific embodiment, the flat cathode 100 of the X-ray tube includes four cathode pieces 110, each cathode piece 110 is fan-shaped, and the angle between the center circumference of the flat cathode 100 and each cathode piece 110 is 90°. In another specific embodiment, the flat cathode 100 may also include three cathode pieces 110, five cathode pieces 110, or six cathode pieces 110, etc., which are not particularly limited.

[0071] See also Figure 3 , the angle θ between the flat cathode 100 of the cathode assembly of the X-ray tube provided in some embodiments of the present application and the central axis p of the flat cathode 100 1 Satisfy the conditions: 45°≤θ 1 ≤86°. By setting θ 1 It is set within a range of greater than or equal to 45° and less than or equal to 86°, so that the flat cathode 100 of the entire X-ray tube forms a spherical structure, and the entire cathode assembly is a Pierce cathode gun that is approximately spherical, so that the focal spot uniformity of the electron beam 140 is better, thereby increasing the life of the X-ray tube target disk.

[0072] In one specific embodiment, the angle θ1 between the flat cathode 100 of the X-ray tube and the central axis p of the flat cathode 100 is 45°. In another specific embodiment, the angle θ1 between the flat cathode 100 of the X-ray tube and the central axis p of the flat cathode 100 is 86°. In another specific embodiment, the angle θ1 between the flat cathode 100 of the X-ray tube and the central axis p of the flat cathode 100 is 50°. In yet another specific embodiment, the angle θ1 between the flat cathode 100 of the X-ray tube and the central axis p of the flat cathode 100 is 70°.

[0073] In some embodiments, the angle θ1 between the flat cathode 100 of the cathode assembly of the X-ray tube and the central axis p of the flat cathode 100 satisfies the condition: 60°≤θ1≤80°. By setting θ1 to be greater than or equal to 60° and less than or equal to 80°, the flat cathode 100 of the entire X-ray tube forms a spherical structure, and the entire cathode assembly is a Pierce cathode gun that is approximately spherical, so that the focal spot uniformity of the electron beam 140 is better, thereby improving the life of the X-ray tube target disk.

[0074] In one specific embodiment, the angle θ1 between the flat cathode 100 of the X-ray tube and the central axis p of the flat cathode 100 is 60°. In another specific embodiment, the angle θ1 between the flat cathode 100 of the X-ray tube and the central axis p of the flat cathode 100 is 80°. In another specific embodiment, the angle θ1 between the flat cathode 100 of the X-ray tube and the central axis p of the flat cathode 100 is 65°. In yet another specific embodiment, the angle θ1 between the flat cathode 100 of the X-ray tube and the central axis p of the flat cathode 100 is 75°.

[0075] See also Figure 3 The cathode assembly of the X-ray tube provided in one embodiment of the present application further includes a base 130, and the base 130 is used to install the flat cathode 100. The shape of the installation surface 131 of the base 130 corresponds to the shape of the flat cathode 100, and the surface of the base 130 for installing the corresponding cathode plate 110 is parallel to the corresponding cathode plate 110. By making the surface of the base 130 for installing the corresponding cathode plate 110 parallel to the surface of the corresponding cathode plate 110, for example, when the surface of the cathode plate 110 is a curved surface, the surface of the base 130 for installing the corresponding cathode plate 110 is also a curved surface. When the surface of the cathode plate 110 is a plane, the surface of the base 130 for installing the corresponding cathode plate 110 is also a plane. Moreover, the shape of the mounting surface 131 of the base 130 corresponds to the shape of the flat cathode 100, so that the installation and fixation of each cathode plate 110 to the base 130 is relatively convenient, and at the same time, the installation angle of the cathode plate 110 relative to the central axis p of the flat cathode 100 can be effectively guaranteed, so that the installation error between the multiple cathode plates 110 is relatively small, thereby making the accuracy of the electron beam 140 finally emitted by the flat cathode 100 higher.

[0076] See also Figure 3 In one embodiment of the present application, a gap 132 is provided between the flat cathode 100 and the base 130 of the cathode assembly of the X-ray tube. By providing the gap 132 between the flat cathode 100 and the base 130, the flat cathode 100 is easy to dissipate heat.

[0077] See also Figure 2 In one embodiment of the present application, the cathode plates 110 of the cathode assembly of the X-ray tube are all of equal size and shape, and the cathode plates 110 are arranged at equal angles along the circumference of the flat cathode 100. The shapes and sizes of the cathode plates 110 are set to be equal, so that the electron beams 140 emitted by each cathode plate 110 have the same size and shape, making it easier to accurately control the beam spot size and beam spot position of the emitted electron beam 140; at the same time, the structure of the entire flat cathode 100 can be more compact; and the processing and forming of the cathode plates 110 is also more convenient. For details, please refer to Figure 3 In one embodiment, the flat cathode 100 includes four cathode plates 110 , each cathode plate 110 is disposed at an angle of 90° along the circumference of the flat cathode 100 .

[0078] In one embodiment, the angles between the plurality of cathode sheets 110 and the central axis p of the flat cathode 100 are all equal. By making the angles between the plurality of cathode sheets 110 and the central axis p of the flat cathode 100 all equal, the spherical structure of the flat cathode 100 formed by the plurality of cathode sheets 110 being arranged together is improved, and the entire cathode assembly is more likely to become a spherical Pierce cathode gun, so that the focal spot uniformity of the electron beam 140 is better, thereby improving the life of the target disk of the X-ray tube.

[0079] See also Figure 2 A fixing area 120 is provided between the multiple cathode plates 110 of the cathode assembly of the X-ray tube provided in an embodiment of the present application, and the fixing area 120 is used to fix and separate the cathode plates 110. By providing the fixing area 120, the cathode plates 110 adjacent to each other can be separated and isolated, so that when the single cathode plates 110 conduct current and emit electron beams 140 separately, they are not easily affected by each other.

[0080] See also Figure 2 The fixing area 120 of the cathode assembly of the X-ray tube provided in one embodiment of the present application is provided with a current input position 121 and a current output position 122, the number of which is equal to the number of the cathode pieces 110, and the current input position 121 and the current output position 122 are used to control the emission of the electron beam 140 of the cathode piece 110. When the cathode piece 110 is required to emit the electron beam 140, the current input position 121 and the current output position 122 are connected to an external power source, so that the external power source supplies power to the cathode piece 110, so that the cathode piece 110 emits the electron beam 140.

[0081] See also Figure 2 In one embodiment of the present application, a fixing position 123 is further provided on the fixing area 120 of the cathode assembly of the X-ray tube. The fixing position 123 is used to fix the cathode plate 110 on the fixing area 120 .

[0082] In one embodiment, the cathode assembly of the X-ray tube includes a grid, which is spaced apart from the focusing electrode 200 along the central axis p of the flat cathode 100, and the grid is used to adjust the intensity of the electron beam 140 passing through the focusing electrode 200. The intensity of the electron beam 140 is adjusted by the grid, so that the intensity of the electron beam 140 can meet the requirements of different usage conditions.

[0083] In one specific embodiment, a plane perpendicular to the central axis p of the planar cathode 100 is taken as a preset plane, and the orthographic projection of the focusing electrode 200 on the preset plane coincides with the orthographic projection of the gate on the preset plane.

[0084] See also Figure 2 The cathode sheet 110 of the cathode assembly of the X-ray tube provided in an embodiment of the present application is in the shape of a sector, and the flat cathode 100 is in the shape of a circle. By setting the cathode sheet 110 in the shape of a sector, the flat cathode 100 formed by arranging a plurality of cathode sheets 110 in the circumferential direction around the center of the flat cathode 100 is a circular structure, and then the entire flat cathode 100 forms a spherical structure, and the entire cathode assembly is a Pierce cathode gun that is approximately spherical, so that the focal spot uniformity of the electron beam 140 is better, so as to improve the life of the target disk of the X-ray tube.

[0085] See also Figure 1 An X-ray tube provided in one embodiment of the present application includes an anode target plate 500, which is arranged on one side of the beam output direction of the flat cathode 100 along the central axis p direction of the flat cathode 100, and the electron beam 140 is used to bombard the target plate edge 510 of the anode target plate 500 and generate an X-ray beam 600.

[0086] See also Figure 1 The X-ray tube provided in one embodiment of the present application further includes a rotating shaft 520 , one end of the rotating shaft 520 is connected to the driving member, and the other end is connected to the anode target plate 500 , and the rotating shaft 520 can drive the anode target plate 500 to rotate around the axis p of the rotating shaft 520 .

[0087] See also Figure 1 The X-ray tube provided in one embodiment of the present application includes a vacuum enclosure 400, the vacuum enclosure 400 is configured with a beam channel 410, the beam channel 410 is arranged between the cathode assembly and the anode target plate 500, a magnetic focusing device 300 is arranged outside the beam channel 410, and the length of the beam channel 410 matches that of a magnetic focusing device 300. By setting the length of the beam channel 410 to match that of a magnetic focusing device 300, the beam channel 410 of the X-ray tube is shorter, and the structure of the entire X-ray tube is more compact.

[0088] It should be noted that, since the cathode assembly provided in the present application forms a spherical structure similar to Pierce, the electron beam 140 emitted by the cathode assembly has certain focusing characteristics. Therefore, the X-ray tube provided in the present embodiment only needs to use one magnetic focusing device 300 to meet the final focusing requirements of the electron beam 140, so that the structure of the X-ray tube provided in the present application is relatively compact.

[0089] The present application also provides a CT device, which includes the X-ray tube described in any one of the above embodiments and can achieve at least one of the above technical effects.

[0090] The present application also provides an X-ray focus adjustment method, which adopts the X-ray tube described in any of the above embodiments; the X-ray focus adjustment method includes: obtaining the working mode of the X-ray tube; applying a preset current to the flat cathode 100 according to the working mode to control one or more of the multiple cathode plates 110 of the flat cathode 100 to be selectively turned on and emit an electron beam 140; wherein the working mode includes a small focus mode in which a single cathode plate 110 emits an electron beam 140 and a large focus mode in which at least two or more cathode plates 110 emit an electron beam 140.

[0091] According to the obtained working mode of the X-ray tube, a preset current is applied to the flat cathode 100, thereby controlling one or more selectable conduction of the plurality of cathode plates 110 of the flat cathode 100, so that the X-ray tube can be as follows: Figure 4 The single cathode plate 110 emits the electron beam 140 in a small focus mode, which can also be as shown in FIG. Figure 5-Figure 7 At least two cathode plates 110 are shown emitting electron beams 140 in a large focal pattern.

[0092] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0093] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A cathode assembly, characterized in that: The cathode assembly comprises: A flat cathode (100), the flat cathode (100) comprising a plurality of cathode sheets (110), the plurality of cathode sheets (110) being arranged circumferentially around the center of the flat cathode (100), the plurality of cathode sheets (110) being arranged at an acute angle to the central axis of the flat cathode (100); each cathode sheet (110) being capable of emitting an electron beam (140) individually; A focusing electrode (200) is arranged around the periphery of the flat cathode (100); the focusing electrode (200) has a focusing surface (210), the angle between the focusing surface (210) and the central axis of the flat cathode (100) is an acute angle, and the focusing electrode (200) is used to focus the electron beam (140) emitted by the flat cathode (100).

2. The cathode assembly according to claim 1, characterized in that The included angle θ1 between the flat cathode (100) and the central axis of the flat cathode (100) satisfies the condition: 45°≤θ1≤86°.

3. The cathode assembly according to claim 2, characterized in that The cathode assembly further comprises a base (130) for mounting the flat cathode (100); the shape of a mounting surface (131) of the base (130) corresponds to the shape of the flat cathode (100); and the surface of the base (130) for mounting the corresponding cathode sheet (110) is parallel to the surface of the corresponding cathode sheet (110).

4. The cathode assembly according to claim 3, characterized in that A gap (132) is provided between the flat cathode (100) and the base (130).

5. The cathode assembly according to claim 1, characterized in that The shapes and sizes of the plurality of cathode sheets (110) are all equal, and the plurality of cathode sheets (110) are arranged at equal angles along the circumference of the flat cathode (100).

6. The cathode assembly according to claim 1, characterized in that The included angles between the plurality of cathode sheets (110) and the central axis of the flat cathode (100) are all equal.

7. The cathode assembly according to claim 1, characterized in that A fixing area (120) is provided between the plurality of cathode sheets (110), and the fixing area (120) is used to fix and separate the cathode sheets (110).

8. The cathode assembly according to claim 7, characterized in that The fixed area (120) is provided with a current input position (121) and a current output position (122), the number of the current input position (121) and the current output position (122) being respectively equal to the number of the cathode plates (110), and the current input position (121) and the current output position (122) are used to control the emission of the electron beam (140) of the cathode plate (110).

9. The cathode assembly according to claim 1, characterized in that The cathode assembly comprises a grid electrode, which is spaced apart from the focusing electrode (200) along the central axis of the flat cathode (100), and is used to adjust the intensity of an electron beam passing through the focusing electrode (200).

10. An X-ray tube, characterized in that: The cathode assembly comprises the cathode assembly as claimed in any one of claims 1 to 9, and further comprises a magnetic focusing assembly, wherein the magnetic focusing assembly comprises at least one magnetic focusing device (300), and the magnetic focusing device (300) comprises a solenoid, a quadrupole magnet or a guide magnet.

11. The X-ray tube according to claim 10, characterized in that The X-ray tube comprises a vacuum-enclosed shell (400), the vacuum-enclosed shell (400) is configured with a beam channel (410), the beam channel (410) is used to be arranged between the cathode assembly and the anode target plate (500), a magnetic focusing device (300) is arranged outside the beam channel (410), and the length of the beam channel (410) matches that of the magnetic focusing device (300).

12. A CT device, characterized in that: Includes the X-ray tube according to claim 10 or claim 11.

13. An X-ray focus adjustment method, characterized in that: Using the X-ray tube according to claim 10 or claim 11; The X-ray focus adjustment method comprises: Obtaining an operating mode of the X-ray tube; Applying a preset current to the flat cathode (100) according to the working mode to control one or more of the plurality of cathode sheets (110) of the flat cathode (100) to selectively conduct and emit an electron beam (140); The working modes include a small focus mode in which a single cathode plate (110) emits an electron beam (140) and a large focus mode in which at least two cathode plates (110) emit an electron beam (140).

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