Patent Application
20180190465
This application is based upon and claims priority to Chinese Patent Application No. 201611246012.8, filed on Dec. 29, 2016, the entire contents thereof are incorporated herein by reference.
The present disclosure relates to a cathode assembly, an X-ray source and a CT device having the cathode assembly.
X-ray is widely used in the fields of industrial non-destructive test, safety inspection, medical diagnosis and treatment. In particular, X-ray radiographic imaging devices owing to the high penetration performance of X-rays play an important role in all aspects of people's daily life. These devices were presented as film-based planar fluoroscopic imaging devices previously. At present, these devices with advanced technology are regarded as stereoscopic imaging devices with digital, multi-view; and high-resolution, for example computed tomography (CT), which may acquire high-resolution 3D stereoscopic image or slicing image as an advanced high-end application.
In the existing CT device, the X-ray generating device moves on the slip ring. In order to improve inspecting speed, moving speed of the X-ray generating device is usually quite fast, and thereby decreases reliability and stability throughout the device. In addition, due to limitation of the moving speed, the inspecting speed of the CT is also limited, so that inspection efficiency is lower. Furthermore, the X-ray sources of such devices move on the slip ring to cause focus of the equivalent X-ray sources larger such that the imaged pictures have motion artifacts and poor in the imaged images, poor resolution, and there is a possibility of missing inspection for some smaller contrabands. Besides, such devices may only inspect stationary (or slow-moving) objects but almost cannot form a three-dimensional image for the moving object.
Hot cathodes serve as electronic emission units and are arranged in array. The voltage between the hot cathode grids is used to control emission of electrons so as to control each cathode to emit electrons in sequence and to bombard target points on the anodes in the corresponding sequence, to establish an arranged X-ray source. By using an electronic switch instead of mechanical rotation of a spiral CT, the X-ray source may be rapidly generated from many views to rapidly image in different angles. This method may greatly improve inspection efficiency and enhance sharpness of the images. And, this scheme structure is simple, the system is stable and the reliability is higher.
In order to improve imaging quality of arranged light sources, it is generally required that light sources from the arranged light source are determined in a range of several tens to hundreds (as required), which means that a large amount of cathodes are required. The current design scheme is provided such that the cathode, a beam control electrode (grid), a compensation focus electrode is integrated together, if one of the cathodes (or cathode assembly) malfunctions, detaching and replacing are very complicated. Thus, the current design scheme is very inconvenient in terms of maintenance and replacement of an equipment.
The contents as above disclosed in this background are only employed to enhance understanding the technical background of this disclosure, thereby the existing knowledge that are not well-known for those skilled in the art may be included in this disclosure.
Additional aspects and advantages of this disclosure will be set forth in part in the description and will be obvious in part from the description, or may be learned by implementation of this disclosure.
According to one aspect of this disclosure, a cathode assembly includes a ceramic plug and a ceramic socket. The ceramic plug has a first end portion and a second end portion arranged opposite to each other, wherein four wiring terminals are provided on an outer end surface of the first end portion, and a protruding positioning part is provided on a periphery surface of the first end portion; an internal cavity is formed in the ceramic plug, the internal cavity has an opening positioned at the second end portion; a cathode is provided in the internal cavity; the cathode has a filament with an positive electrode lead and a negative electrode lead; a grid is provided on an end surface of the second end portion and has a grid voltage signal line, the cathode has a cathode surface lead and the positive electrode lead, the negative electrode lead, the grid voltage signal line and the cathode surface lead are electrically connected to one of the wiring terminals, respectively. The ceramic socket has four wiring tubes, wherein the ceramic socket may be in contact with the first end portion of the ceramic plug, and the four wiring tubes may be electrically connected with the four wiring terminals.
According to another aspect of this disclosure, an X-ray source includes a vacuum chamber, an anode target provided in the vacuum chamber, a mounting plate provided in the vacuum chamber and separately provided with the anode target, and a plurality of mounting holes are provided on the mounting plate, a focus electrode, provided between the anode target and the mounting plate, wherein a plurality of focus through holes through which the electrons pass and which are in coincidence with the mounting holes are provided on the focus electrode, a compensation electrode provided between the focus electrode and the mounting plate, wherein a plurality of compensation through holes through which the electrons pass are provided on the compensation electrode, and the compensation through hole is in coincidence with the focus through holes such that the electrons may pass through the compensation through hole and the focus through hole orderly; and a plurality of the cathode assemblies of present disclosure detachably connected to the mounting hole, wherein the positioning part of the ceramic plug of the cathode assembly is matched with the mounting hole to position the cathode assembly.
According to another aspect of this disclosure, a CT device includes the present X-ray source.
The foregoing features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings.
In the drawings, 1. ceramic plug; 10. positioning part; 11. wiring terminal; 12. grid; 13. groove; 14. grid voltage signal line; 15. counter bore 17. internal cavity; 18. cathode; 181. filament; 182. positive electrode lead; 183. negative electrode lead; 184. support leg; 185. ceramic insulating ring; 186. metal fixing ring; 187. snapping part; 19. positioning hole; 2. ceramic socket; 21. wiring tube; 22. air hole; 23. annular flange; 3. vacuum chamber; 4. anode target; 5. mounting plate; 51. mounting hole; 6. focus electrode; 61. focus through hole; 7. compensation electrode; 71. compensation through-hole; 81. first cartridge; 82. second cartridge; 83. pressure plate; 84. fixing screw; 91. high-voltage connection device; 92. high-voltage connection device; 93. high-voltage power supply; 94. compensation focus power supply; 100. cathode assembly.
Exemplary embodiments will be completely described with reference to the drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure is thorough and complete, and will fully convey the scope of this disclosure to those skilled in the art. The same reference hers will be used throughout the drawings to refer to the same or like parts, thereby the detailed description thereof will be omitted.
Referring to to
As shown in
The grid 12 is used to control whether the cathode 18 emits electrons. The cathode 18 is switched off and thereby does not emit the electrons when the grid 12 is under a negative bias voltage, and the cathode 18 may emit electrons when the grid 12 is under a positive bias voltage.
Furthermore, as shown in
As shown in
As shown in
As shown in
Further, in this embodiment, the metal fixing ring 186 is welded in the counter bore 15. During welding, the inner wall of the counter bore 15 is firstly metalized, and then the metal fixing ring 186 is welded to the counter bore 15. The metal fixing ring 186 of this embodiment may further be an elastic ring with an opening. A snapping part 187 bent outward is further disposed on the metal fixing ring 186, while an annular slot is disposed in the interior of the counter bore 15. The metal fixing ring 186, after being inserted into the counter bore 15, may be expanded under its own elastic force so that the snapping part 187 of the metal fixing ring engages with the annular slot, and then the welding of the metal fixing ring 186 may be completed, consequently the metal fixing ring is fixed more reliably. In this way, the metal fixing ring 186 will be remained in the counter bore 15 even if the welding portion of the metal fixing ring 186 loses effectiveness due to high temperature melting, to ensure system reliability.
Referring to
It should be understood by the person skilled in the art that the way by which the cathode 18 is connected to the ceramic plug 1 is not limited, and also may not have the support leg 184.
The cathode assembly 100 of this disclosure has a simple and compact structure, if maintenance and replacement are required, it is more convenient to only disassemble the cathode assembly but without disassembling the compensation electrode and the focus electrode of the X-ray source. Significantly, the cost for maintenance and replacement may be reduced, convenience for the maintenance is improved, and the service life of the device may be prolonged.
The anode target 4, the cathode assembly 100, the mounting plate 5, the focus electrode 6 and the compensation electrode 7 are all disposed in the vacuum chamber 3. The anode target 4 and the mounting plate 5 are substantially parallel to each other. The mounting plate 5 and the anode target 4 are arranged at intervals. The focus electrode 6 is located between the mounting plate 5 and the anode target 4 while the compensation electrode 7 is located between the focus electrode 6 and the mounting plate 5. The distance between the anode 4, the focus electrode 6, the compensation electrode 7, and the mounting plate 5 may be adjusted according to the requirements. A ceramic pressure plate may be provided between the compensation electrode 7 and focus electrode 6 to achieve positioning the compensation electrode 7 and focus electrode 6. The anode target 4 is connected to the high-voltage power supply 93 outside the vacuum chamber 3 through a high-voltage connection device 91, whereas the focus electrode 6 and the compensation electrode 7 are connected to the compensation focus power supply 94 outside the vacuum chamber 3 via the high-voltage connection device 92.
A plurality of mounting holes 51 are provided on the mounting plate 5. A plurality of focus through holes 61, through which electrons pass, are provided on the focus electrode 6. The center lines of the focus through holes 61 and the mounting holes 51 are collinear respectively. A plurality of compensation through holes 71, through which the electrons pass, are provided on the compensation electrode 7. The center lines of the compensation through holes 71 and the focus through holes 61 are collinear respectively, such that the electrons orderly pass through the compensation through holes 71 and the focus through holes 61.
The cathode assembly 100 is detachably connected to the mounting hole 51. When the cathode assembly 100 is connected, the positioning part 10 on the ceramic plug 1 of the cathode assembly 100 is matched with the mounting hole 51 for a purpose of positioning the cathode assembly 100. It should be understood by the person skilled in the art that the ways for connecting the cathode assembly 100 to the mounting hole 51 is not limited. In this embodiment, the mounting plate 5 is provided with a locking device for locking the cathode assembly 100. The locking device includes a first cartridge 81, a second cartridge 82, and a pressure plate 83.
The first cartridge 81 and the second cartridge 82 are fixedly mounted on the mounting plate 5 by the fixing screws 84 and are respectively located on both sides of the mounting hole 51. The pressure plate 83 has one end pivotally connected to the first cartridge 81, and the pressure plate 83 may be in a locked state and an unlocked state. When the pressure plate 83 is in the locked state, the other end of the pressure plate 83 may be engaged with the second cartridge 82, at the moment, the pressure plate 83 may press against the ceramic socket 2 of the cathode assembly 100 such that the cathode assembly 100 is fixedly connected onto the mounting plate 5. When the pressure plate 83 is in the unlocked state, the pressure plate 83 is separated from the second cartridge 82 and away from the ceramic socket 2, as a result, the cathode assembly 100 may be removed from the mounting plate 5.
Furthermore, in this embodiment, the pressure plate 83 is a frame-type structure, and the ceramic socket 2 has an annular flange 23, and the pressure plate 83 may be sleeved on the ceramic socket 2 and press against the annular flange 23.
When the X-ray source according to the embodiment of this discourse is in use, the cathode 18 is at a ground potential, while the grid 12, the focus electrode 6 and the compensation electrode 7 are at a low positive pressure. An appropriate voltage is applied on the compensation electrode 7 for adjusting the electric field strength on both ends of the grid 12, to ensure that the electron has the smallest increase of the emittance after passing through the grid 12, thereby focusing of the beam current becomes easier. The voltage of the compensation electrode 7 is properly raised to reduce rate of the electrons captured by the grid 12 so as to improve the electron utilization rate. Voltage of the focus electrode may be adjusted to focus the beam current to a right dimension. The electrons emitted by the cathode 18 orderly pass through the grid 12, the compensation through hole 71 on the compensation electrode 7, and the focus through hole 61 on the focus electrode 6, and finally reach the anode target 4. The anode target 4 is at a positive high pressure, and the electron energy is thereby converted to X-ray at the anode target 4.
If it is required to replace the cathode assembly 100, what only need to do is to unlock the pressure plate 83 of the locking device, at the moment, the cathode assembly 100 is removed from the mounting plate 5, and then is replaced with a new cathode assembly. During this replacement action is not required for the focus electrode and the compensation electrode, and thereby the replacement is quick and easy, which reduces labor cost as desired for installation and replacement and also facilitates maintenance and replacement of the device.
This disclosure also discloses a CT device, which includes an X-ray source according to an embodiment of present disclosure.
The cathode assembly of this disclosure may be assembled by plugging the ceramic plug into the ceramic socket, and may be removed directly from the X-ray source when the cathode assembly is required to be replaced, without performing any operation to the focus electrode and the compensation electrode of the X-ray source, as a result, the installation and replacement are convenient and quick, labor cost as required for installation and replacement may be reduced, and maintenance and replacement of the device become easier.
While the present disclosure has been described in detail in connection with the exemplary embodiments, it should be readily understood that the present disclosure is not limited to such disclosed embodiments. Rather, various alternations and equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201611246012.8 | Dec 2016 | CN | national |
