X-ray tube, X-ray source and irradiation device

Abstract

The utility model provides an X-ray tube, an X-ray source and an irradiation device, the X-ray tube comprises a ray tube body, a cathode structure extending along a set surface and an anode target arranged at an interval with a cathode are arranged in a vacuum cavity formed by the ray tube body; the heat dissipation structure comprises a liquid cooling pipeline and is arranged on the side, away from the cathode structure, of the anode target, the heat dissipation structure is welded to the ray tube body, and the part, welded to the heat dissipation structure, of the ray tube body is of a metal structure; and the focus control electrode pair is arranged between the cathode structure and the anode target and is used for controlling the motion path of the electrons emitted from the cathode structure through voltage applied between the focus control electrode pair, so that the focus range formed by focusing the electrons emitted from the cathode structure on the anode target is controlled not to exceed the effective heat dissipation range on the anode target. According to the utility model, the X-ray tube with stronger heat dissipation capability can be prepared, so that the high-power and long-time continuous work of the X-ray tube can be realized.

Description

Technical Field

[0001] The utility model relates to the technical field of irradiation, in particular to an X-ray tube, an X-ray source and an irradiation device. Background Art

[0002] Irradiation technology is a treatment method that uses the interaction between high-energy rays and matter to achieve sterilization, preservation, and material modification. High-energy rays commonly used in industry include gamma rays produced during the decay of radioactive isotopes, high-energy electron beams produced by electron accelerators, and X-rays produced by X-ray tubes. Compared with other high-energy rays, X-ray tubes are easier to protect.

[0003] Traditional fixed anode X-ray tubes are mainly used in intermittent work such as imaging or low-dose irradiation scenarios such as blood irradiation due to the requirements of imaging focus and the limitation of anode heat dissipation capacity. They are difficult to meet the irradiation requirements of high-dose continuous operation of radiation sources such as sterilization and modification. Improving the heat dissipation structure and increasing the focus area of ​​electrons on the anode are two ways to improve the heat dissipation capacity of the anode and thus realize continuous high-power operation of the X-ray source.

[0004] Existing X-ray tubes are often made of materials such as ceramics or glass to form a heat dissipation structure by reserving axial concentric pipes in the metal anode head connected to the back of the anode target. When the X-ray tube is in use, external cooling liquid can flow in from the central pipe and then flow out from the peripheral pipe. However, due to the large difference in thermal expansion coefficients between metal and ceramic or glass, in order to ensure the airtightness of the sealing interface between the two after the anode temperature rises, the size of the sealing interface of the X-ray tube is often small, so the complexity of the heat dissipation structure is limited, and it is difficult to use a large flow and complex pipe design to improve the heat dissipation capacity of the anode.

[0005] Furthermore, although the current X-ray tubes using rotating anodes can increase the actual focal area formed by the emitted electrons, thereby reducing the local heat dissipation pressure, the target material rotates at a high speed, which significantly increases the manufacturing cost and is not suitable for irradiation purposes that do not require the size of the focal spot.

[0006] Therefore, it is urgent to prepare an X-ray tube with strong heat dissipation capability to achieve high-power and long-term continuous operation. Utility Model Content

[0007] In view of this, the embodiments of the utility model provide an X-ray tube, an X-ray source and an irradiation device, which can improve the heat dissipation capacity of the anode by improving the heat dissipation structure and increasing the electron focus area to achieve continuous high-power operation of the device.

[0008] One aspect of the utility model provides an X-ray tube, comprising:

[0009] A ray tube body, the ray tube body is used to form a closed vacuum cavity, and a cathode structure extending along a set surface and an anode target spaced apart from the cathode are arranged inside the cavity formed by the ray tube body;

[0010] A heat dissipation structure, comprising a liquid cooling pipe, the heat dissipation structure is in direct or indirect contact with the anode target and is arranged on a side of the anode target away from the cathode structure, and the heat dissipation structure is welded to the ray tube body, and the portion of the ray tube body welded to the heat dissipation structure is a metal structure;

[0011] A focus control electrode pair is arranged between the cathode structure and the anode target, and is used to control the movement path of electrons emitted from the cathode structure by applying a voltage between the focus control electrode pair, thereby controlling the focus range formed by the electrons emitted from the cathode structure focusing on the anode target to not exceed the effective heat dissipation range on the anode target.

[0012] In some embodiments of the present invention, the heat dissipation structure further includes a heat dissipation substrate, which is used to cover the liquid cooling pipe and is in direct contact with the anode target to dissipate heat from the anode target.

[0013] In some embodiments of the present invention, a temperature sensor is disposed inside or outside the heat dissipation substrate.

[0014] In some embodiments of the present invention, the cathode structure includes one electron emitter or multiple electron emitters connected in parallel, each electron emitter is in the shape of a wire, a rod or a sheet, wherein the wire-shaped electron emitter is in the shape of a straight line or a spiral line.

[0015] In some embodiments of the present invention, the cathode structure further includes an elastic stretching structure connected between one end of the electron emitter and an extraction electrode of the electron emitter, for stabilizing the position of the electron emitter by stretching.

[0016] In some embodiments of the present invention, the anode target is a plane or a curved surface, and the arrangement size of the electron emitter in each direction of the set surface is smaller than the size of the anode target in the corresponding direction.

[0017] In some embodiments of the present invention, the X-ray tube further comprises: a grid, the grid being disposed between the cathode structure and the anode target; and / or

[0018] The electron shielding structure is placed on the side of the cathode structure facing away from the anode target.

[0019] In some embodiments of the present invention, the liquid cooling pipeline adopts a single-tube circuitous arrangement or a multi-tube shunt arrangement to form a heat dissipation surface that fits the anode target.

[0020] Another aspect of the present invention provides an X-ray source, the X-ray source comprising:

[0021] The X-ray tube according to any one of the above embodiments; and

[0022] The additional tube body is connected to one end of the lead-out electrode with a cathode structure of the ray tube body. The additional tube body is provided with an insulator close to the side of the ray tube body and a negative high-voltage plug located on the side away from the ray tube body.

[0023] Another aspect of the present invention provides an X-ray irradiation device, comprising:

[0024] The X-ray source described in the above embodiment includes a support structure for fixing the X-ray source, an irradiation table located in the irradiation area of ​​the X-ray source, and a shielding box.

[0025] The X-ray tube, X-ray source and irradiation device proposed in the utility model can fix the heat dissipation structure and the X-ray tube body in the form of all-metal welding, reducing the possibility of X-ray tube leakage due to temperature changes at the interface between the heat dissipation structure and the tube body, thereby improving the heat dissipation capacity of the X-ray tube from the perspective of improving the heat dissipation structure; moreover, the application matches the effective heat dissipation range formed by the electron focus range and the liquid cooling pipeline through the focus control electrode pair, which can effectively reduce the target surface temperature from the perspective of increasing the electron focus area. Based on the above-mentioned improvement angle, the application can prepare an X-ray tube with strong heat dissipation capacity, so that the X-ray tube can work continuously at a higher power.

[0026] Additional advantages, purposes, and features of the present invention will be partially described in the following description, and will become partially apparent to those skilled in the art after studying the following, or may be learned from the practice of the present invention. The purposes and other advantages of the present invention can be achieved and obtained by the structures specifically pointed out in the specification and the drawings.

[0027] Those skilled in the art will understand that the purposes and advantages that can be achieved by the present invention are not limited to the above specific description, and the above and other purposes that can be achieved by the present invention will be more clearly understood based on the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of the present application, and do not constitute a limitation of the present invention. The components in the drawings are not drawn to scale, but are only for the purpose of illustrating the principles of the present invention. In order to facilitate the illustration and description of some parts of the present invention, the corresponding parts in the drawings may be enlarged, that is, they may become larger relative to other components in the exemplary device actually manufactured according to the present invention. In the drawings:

[0029] Figure 1It is a schematic diagram of the structure of an X-ray tube in one embodiment of the utility model.

[0030] Figure 2 It is a schematic diagram of the structure of the liquid cooling pipeline in one embodiment of the utility model.

[0031] Figure 3 Schematic diagram of the structure of a focus control electrode pair in one embodiment of the utility model.

[0032] Figure 4 Schematic diagram of the cathode structure in one embodiment of the utility model.

[0033] Figure 5 It is a schematic diagram of a cathode structure in another embodiment of the present invention.

[0034] Figure 6 This is an electron probability density distribution diagram obtained by simulating a specific electron emission structure in one embodiment of the present invention.

[0035] Figure 7 This is a temperature distribution diagram simulated in a thermal equilibrium state of an X-ray tube in an embodiment of the present invention.

[0036] Figure 8 It is a schematic diagram of an X-ray irradiation device in one embodiment of the utility model.

[0037] Description of Figure Numbers:

[0038] X-ray tube body 110; X-ray window 113; heat dissipation structure 130; liquid cooling pipe 131; heat dissipation substrate 133; cathode structure 150; electron emitter 151; extraction electrode 153; anode target 170; focus control electrode pair 190; metal structure 111; grid 120; electron shielding structure 140; additional tube body 210; negative high voltage plug 250; insulator 230 DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in combination with the implementation mode and the accompanying drawings. Here, the schematic implementation mode of the utility model and its description are used to explain the utility model, but are not used as a limitation of the utility model.

[0040] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme according to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0041] It should be emphasized that the term “include / comprises” when used herein refers to the presence of features, elements, steps or components, but does not exclude the presence or addition of one or more other features, elements, steps or components.

[0042] It should also be noted that, unless otherwise specified, the term “connection” herein may refer not only to a direct connection but also to an indirect connection involving an intermediate.

[0043] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0044] Limited by the principle and preparation process, the X-ray tube in the prior art has a low ultimate heat dissipation capacity, which makes it difficult to meet the irradiation requirements of high-dose rate continuous operation in the fields of sterilization, preservation and material improvement, and the prior art has limited improvements to the heat dissipation structure, making it difficult to effectively improve the anode heat dissipation efficiency while controlling costs. Based on this, the present application adopts an all-metal welding method to fix the heat dissipation structure and the X-ray tube body, so that a large-flow and complex pipeline design can be used later to improve the heat dissipation capacity of the anode target, and the present application controls the focal area formed by the electron flow at the anode through the focus control electrode pair, so that the electrons are uniformly emitted to the anode target. The present application makes improvements from two dimensions: the heat dissipation structure and increasing the electron focal area, which effectively improves the heat dissipation capacity of the X-ray tube to achieve continuous high-power operation of the X-ray source.

[0045] The X-ray tube in this application is a vacuum diode working under high voltage, which at least includes a cathode, an anode and a vacuum chamber. When working, the electrons emitted by the cathode bombard the anode under the acceleration of the electric field, and most of the energy of the high-energy electrons remains in the anode in the form of heat energy, and a small part of the energy is emitted in the form of X-rays. Figure 1 FIG. 1 is a schematic diagram of an X-ray tube in one embodiment of the present invention. Figure 1 As shown, the X-ray tube proposed in this application includes:

[0046] The ray tube body 110 is used to form a closed vacuum cavity, and a cathode structure 150 extending along a set surface and an anode target 170 (or an anode target structure 170) spaced apart from the cathode are arranged inside the cavity formed by the ray tube body 110;

[0047] a heat dissipation structure 130, which includes a liquid cooling pipe 131, the heat dissipation structure 130 is in direct or indirect contact with the anode target 170 and is disposed on a side of the anode target 170 away from the cathode structure 150, and the heat dissipation structure 130 is welded to the ray tube body 110, and the portion of the ray tube body 110 welded to the heat dissipation structure 130 is a metal structure 111 (for example, the heat dissipation structure at the welded portion may also be made of a metal material);

[0048] The focus control electrode pair 190 (including a first focus control electrode 191 and a second focus control electrode 193) is arranged between the cathode structure 150 and the anode target 170, and is used to control the movement path of electrons emitted from the cathode structure 150 in the X-ray tube by applying a voltage between the focus control electrode pair 190, so as to control the electron beam emitted from the cathode structure 150 to be focused on the anode target 170, and the focus range formed by the electrons emitted from the cathode structure 150 being focused on the anode target 170 does not exceed the effective heat dissipation range on the anode target 170.

[0049] Since a high voltage needs to be applied to the X-ray tube during use, the tube body 110 is usually de-energized to ensure safety, for example, the tube body 110 is grounded. In addition, an X-ray window 113 for transmitting the X-rays generated by the anode target structure 170 is provided on the tube body 110. The portion where the tube body and the heat dissipation structure 130 are welded is a metal structure 111, which can be made of the same metal material as the heat dissipation structure at the welding location, or the metal structure 111 can be made of a metal material with good welding compatibility with the heat dissipation structure at the welding location; the X-ray window 113 can be made of a metal with high ray transmittance (such as aluminum, beryllium, and titanium), an alloy material, or glass to reduce the absorption of X-rays by the tube body; except for the portion of the tube body including the metal structure 111 and the X-ray window 113, the other portions of the tube body 110 can be made of no metal material (for example, ceramics, glass, aluminum, beryllium, titanium, and alloys made of aluminum, beryllium, and titanium are selected as the preparation materials) due to the low heat generation. The junctions of different materials on the ray tube body 110 can be connected by vacuum brazing or other methods, so that the ray tube body 110 forms a closed vacuum cavity.

[0050] In order to ensure that the X-ray tube can meet the high-power heat dissipation requirements, the heat dissipation power and thermal resistance of the heat dissipation structure 130 need to be considered. Generally speaking, increasing the coolant flow rate and heat exchange area of ​​the heat dissipation structure 130 can improve the heat dissipation power of the heat dissipation structure 130; and, when the product of the coolant flow rate and the heat exchange area is fixed, increasing the heat exchange area (in this case, the coolant flow rate needs to be reduced) can reduce the convection heat transfer thermal resistance, thereby reducing the surface temperature of the anode target 170. Therefore, the heat dissipation capacity of the heat dissipation structure 130 can be enhanced by increasing the heat exchange area between the heat dissipation structure 130 and the anode target 170. In the present application, the size of the effective heat dissipation range on the anode target 170 can be used to represent the size of the heat exchange area between the heat dissipation structure 130 and the anode target 170. The size of the effective heat dissipation range is determined by the arrangement boundary of the liquid cooling pipe 131 in the heat dissipation structure 130, and the area formed by the projection of the arrangement boundary of the liquid cooling pipe 131 in each direction on the anode target 170 is the effective heat dissipation range.

[0051] In some embodiments of the present invention, the liquid cooling pipe 131 may be arranged in a single-pipe circuitous manner (eg Figure 2 (a)) or multi-pipe flow distribution arrangement (such as Figure 2 (b) and (c) in the figure) form a heat dissipation surface that fits the anode target 170, thereby increasing the area of ​​the liquid cooling pipe 131. For example, the ratio of the effective heat exchange area of ​​the liquid cooling pipe 131 to the cross-sectional area of ​​the liquid cooling pipe 131 (which may refer to the cross-sectional area of ​​the liquid cooling pipe inlet) can be set to be greater than 20. Figure 2 As shown, the liquid cooling pipe 131 is bent to increase the complexity of the liquid cooling pipe 131 , effectively increase the heat exchange area, and improve the heat dissipation capacity of the anode target structure 170 . Figure 2 The liquid cooling pipes in (a) are arranged in series, and the coolant can enter from one end and flow along a single pipe until it flows out; Figure 2 (b) in the figure adopts a parallel pipeline structure, and the coolant can flow in from one end and continue to flow along different pipelines; Figure 2 (c) in the figure adopts a serial-parallel pipeline structure, that is, the pipeline is divided into multiple paths in certain sections of the serial pipeline. The serial structure is easy to keep the flow cross-section basically the same, so the local resistance and erosion are small, which is suitable for use with a large flow external cooling system; the parallel structure is easy to increase the effective heat dissipation area through designs such as multi-channel fins, which is suitable for situations with small flow and small anode target area; the serial-parallel structure is between the two.

[0052] In addition, the heat exchange area of ​​the coolant may be increased by changing the shape of the liquid cooling tube. For example, the liquid cooling tube may include a round tube, a square tube, a star tube, or a fin tube.

[0053] The liquid cooling pipe 131 includes at least one inlet and one outlet, which are used to ensure the normal flow of the cooling liquid.

[0054] In some embodiments of the present invention, the heat dissipation structure 130 further includes a heat dissipation substrate 133 , which is used to cover the liquid cooling pipe 131 and directly contact the anode target 170 to dissipate heat for the anode target 170 .

[0055] If the heat dissipation structure 130 only includes the liquid cooling pipe 131, the liquid cooling pipe 131 is welded to the metal structure 111, and the liquid cooling pipe 131 is in contact with the anode target 170 for heat dissipation; if the heat dissipation structure 130 includes the liquid cooling pipe 131 and the heat dissipation substrate 133, the heat dissipation substrate 133 is welded to the metal structure 111 (it may also include the situation where the liquid cooling pipe 131 is welded to the metal structure 111), and the anode target structure 170 is in contact with the heat dissipation substrate 133 for heat dissipation (in this case, the liquid cooling pipe 131 is in indirect contact with the anode target 170).

[0056] As an example, the heat dissipation substrate 133 can be prepared by a metal material with good thermal conductivity. For example, the preparation material of the heat dissipation substrate includes at least one of the following materials: tantalum, iron, copper and aluminum. In addition, in order to improve the airtightness of the radiation source, metal materials with a difference in metal thermal expansion coefficient of no more than 10% can be used to prepare the part of the heat dissipation structure 130 that is welded to the metal structure 111, and the metal structure 111. That is, the present application adopts the form of full metal sealing to fix the heat dissipation structure 130 through the metal structure 111 to form a closed tube radiation source, thereby reducing the possibility of air leakage after the welding interface is heated and extending the service life of the X-ray tube.

[0057] Furthermore, when the heat dissipation base 133 is used to increase the heat exchange area, a liquid cooling pipe can be directly prepared on the heat dissipation base 133 by drilling, die casting or milling, or the liquid cooling pipe 131 can be arranged inside the hollow heat dissipation base 133 by inlaying or composite welding. In addition, the liquid cooling pipe 131 can be fixed inside the heat dissipation base 133 so that it is not easy to move.

[0058] In some embodiments of the present invention, a temperature sensor is provided inside or outside the heat dissipation substrate 133, and the temperature sensor can be used to measure the temperature of the surface of the anode target structure 170 facing the heat dissipation structure 130 or the temperature of the surface (inner or outer surface) of the liquid cooling pipe 131. For example, the temperature sensor can be provided inside the heat dissipation substrate 133 near the anode target structure 170.

[0059] The cathode structure 150 and the anode target 170 are located inside the ray tube body 110, but to avoid discharge, the cathode structure 150 and the anode target 170 cannot be too close to the ray tube body 110. Figure 1 As shown, the cathode structure 150 and the anode target 170 may be suspended and disposed parallel to each other.

[0060] The above-mentioned arrangement of the cathode structure 150 and the anode target 170 is only an example, and the electrons emitted by the cathode structure 150 can be located within the effective heat dissipation range of the anode target 170 .

[0061] Considering the relative positions of the cathode structure 150, the anode target 170 and the heat dissipation structure 130 in the X-ray tube, and to improve the heat dissipation efficiency, the present application adopts a reflective target as the anode target 170. The anode target 170 is arranged opposite to the X-ray window 113, and is used to generate X-rays and emit them through the X-ray window 113.

[0062] As an example, in order to improve the heat dissipation capability of the anode target 170, the effective heat dissipation range on the anode target 170 is not less than the focus range formed on the anode target 170 by the electron beam emitted by the cathode structure 150. Figure 3As shown, the anode target structure 170 may be a planar structure or a curved structure that is arched toward the cathode structure 150 .

[0063] As an example, the overall height of the heat dissipation structure 130 may be greater than 1 cm, and the thickness of the anode target structure 170 may be greater than 1 mm.

[0064] In some embodiments of the present invention, the shortest distance between the anode target 170 and one side of the tube body including the metal structure 111 is greater than 1 cm, and the minimum distance between the boundary of the metal structure 111 and the center of the liquid cooling pipe 131 at the welding point is 3 cm.

[0065] The anode target 170 may be in direct contact with the heat dissipation structure 130 to reduce thermal resistance, or an intermediate welding layer or solder may be added between the heat dissipation structure 130 and the anode target structure 170 so that the heat dissipation structure 130 and the anode target 170 are in indirect contact, thereby reducing welding stress caused by the mismatch of thermal expansion coefficients between the target material and the heat dissipation structure material. The intermediate welding layer or solder may be a metal or alloy having an alloy phase with the preparation material of the anode target 170 and the heat dissipation substrate 133 (or liquid cooling pipe 131), such as titanium, rhenium, molybdenum, copper, gold or silver. The anode target 170 may be made of one or more of the following materials: tungsten, molybdenum, chromium, rhodium, niobium, tantalum and rhenium.

[0066] The cathode structure 150 can be applied with a voltage to emit electrons, and keep a distance from the grounded tube body 110 to avoid discharge. In addition, when the focus control electrode pair and the cathode structure remain unchanged, the farther the distance between the cathode structure 150 and the anode target 170, the smaller the spatial angle of the cathode structure relative to the target surface, and the smaller the proportion of X-ray attenuation caused by the cathode structure shielding.

[0067] In terms of cathode structure improvement, US Patent No. 7346147B2 discloses a transmission type X-ray source using a linear cathode, which reduces the heat dissipation pressure of a single point on the anode. Chinese invention patent application CN 115954250 A introduces a straight cooling pipe at the back of the anode based on the linear cathode structure, thereby increasing the continuous use power. In this application, the utilization rate of the cathode structure can be improved by setting parallel cathodes.

[0068] In some embodiments of the present invention, Figure 4 As shown, the cathode structure 150 may include one electron emitter 151, or the cathode structure 150 may also include a plurality of electron emitters 151 connected in parallel. The electron emitter 151 is in the shape of a wire, a rod or a sheet, and the wire-shaped electron emitter is in the shape of a line or a spiral.

[0069] The shape of the electron emitter 151 is merely an example, and the present invention is not limited thereto.

[0070] As an example, the electron emitter 151 in the present application may be a thermal emission filament, which is made of one or more of the following materials: tungsten, molybdenum, iridium, osmium, carbon, yttrium oxide, barium oxide, aluminum oxide, scandium oxide, calcium oxide, lanthanum hexaboride, and samarium hexaboride. In addition, although the collimation requirement for electron emission in the X-ray tube of the present application is relatively low, the cathode structure 150 may also be a cold cathode.

[0071] In some embodiments of the present invention, when the electron emitter 151 is a thermal emission filament, since the filament will stretch due to the increase in temperature during operation, it is very easy to cause the focal range to shift. The electron emitter 151 can be kept in a stable position in the X-ray tube with the help of an elastic stretching structure (such as a stretching spring, etc.). That is, the cathode structure 150 can also include an elastic stretching structure connected between one end of the electron emitter 151 and the extraction electrode 153 of the electron emitter 151, which is used to stabilize the position of the electron emitter by stretching. For example, if the cathode structure 150 is an electron emitter connected in parallel, the elastic stretching structure can be as follows: Figure 5 Settings shown.

[0072] In some embodiments of the present invention, the arrangement size of the electron emitter 151 in each direction of the set surface is smaller than the size of the anode target 170 in the corresponding direction.

[0073] In order to fully utilize the heat dissipation capacity of the coolant inside the heat dissipation structure 130, the electrons should be more evenly hit on the anode target 170. The present application adjusts the focus range of the electrons on the anode target 170 by setting a focus control electrode pair 190 between the cathode structure 150 and the anode target 170. The focus control electrode pair 190 may include: Figure 3 The structures shown are symmetrically arranged along the cathode structure 150. The potential of the focus control electrode with negative voltage applied is not higher than the cathode potential (for example, the potential of the focus control electrode pair 190 relative to the cathode structure 150 can be -100V, and the lower the potential on the focus control electrode pair 190, the smaller the electron emission angle, and the smaller the focus range formed by the electrons focusing on the anode target 170), and the potential of the focus control electrode with positive voltage applied is higher than the cathode potential.

[0074] As an example, take Figure 6 The electron emission structure shown in (a) in FIG. 1 is assumed to be a single electron emitter 151 ( Figure 4 The cathode structure shown in (a) is 5 cm away from the planar anode target 170, the tube voltage is 80 kV, and the focus control electrode is 500 V lower than the electron emitter 151. If the electron bombardment position is simulated by the Monte Carlo method, the probability density distribution of the electrons is as follows: Figure 6 As shown in (b) in . Figure 6It can be seen that based on the aforementioned tube-related parameters, combined with the shape and position of the focus control electrode pair 190, it is possible to achieve the effect of bombarding the anode target more evenly while ensuring that all electrons fall within the anode range.

[0075] In some embodiments of the present invention, the X-ray tube further includes: a grid 120, which may be disposed between the cathode structure 150 and the anode target 170; and / or

[0076] The electron shielding structure 140 is disposed on a side of the cathode structure 150 facing away from the anode target 170 .

[0077] More specifically, the grid 120 is arranged between the cathode structure 150 and the anode target 170 to achieve the effect of controlling the electron focus range. When the grid 120 is arranged at a position close to the cathode structure 150, it can not only control the electron focus range, but also limit the ability of the cathode structure 150 to emit electrons in other directions, so as to ensure that as many electrons generated by the cathode structure 150 as possible hit the anode target 170. The grid 120 can be used to control the magnitude of the electron current emitted by the cathode structure 150 and avoid direct sparking between the cathode structure 150 and the anode target 170 to damage the cathode; the electron shielding structure 140 can intercept the electrons emitted by the cathode structure 150 in the direction away from the anode target 170, so as to avoid the electrons directly bombarding the grounded tube body with the same potential as the anode.

[0078] As an example, the corresponding parameters can be set so that the X-ray tube of the present application can work normally and continuously at high power. Assume that the coolant flow rate is 18L / min, the heat dissipation substrate is made of brass (and the liquid cooling pipe is directly prepared on the heat dissipation substrate by drilling, etc.), the diameter of the liquid cooling pipe is 15mm, the thickness of the tungsten target is 5mm, and the heated area of ​​the tungsten target surface is 2cm×10cm, and the coolant in the liquid cooling pipe is water, and the inlet temperature is 20°C. Based on the above parameters, this application uses COMSOL software to simulate the temperature conditions of the X-ray tube when it is working, and the phase change effect caused by excessive water temperature is not considered during the simulation process.

[0079] The present application simulates the maximum temperature that the tungsten target can reach when the X-ray source works at different powers in COMSOL software, and the results are shown in Table 1. Furthermore, the present application simulates the thermal equilibrium state through COMSOL software. At a power of 5 kW (i.e., the electron beam power of the X-ray source), the tungsten target and the heat dissipation substrate made of brass can reach thermal equilibrium within 1 minute, and its temperature distribution is shown in Table 1. Figure 7 In the thermal equilibrium state, the maximum temperature of the heat dissipation substrate is lower than 200°C, the surface temperature of the tungsten target close to the cathode structure is lower than 250°C, and the constant creep strain rate of the heat dissipation substrate is lower than 10 -10 / s, which can effectively avoid the risk of tungsten target falling off from the heat dissipation substrate during long-term use.

[0080] Table 1 Simulated maximum temperature of each structure at different powers (temperature unit: K)

[0081]

[0082] The X-ray tube proposed by the utility model has the following advantages:

[0083] 1. A more complex liquid cooling pipeline structure can be used, and a heat dissipation substrate is provided to increase the heat exchange area between the heat dissipation structure and the anode target structure, so that the heat dissipation capacity of the X-ray tube is stronger, suitable for higher power continuous work, and the total processing speed of a single radiation source is improved.

[0084] 2. The heat dissipation structure and the tube body are welded with all-metal, which reduces the possibility of air leakage after the interface is heated and prolongs the service life of the X-ray tube.

[0085] 3. By adjusting the potential on the focus control electrode pair to change the electron emission angle, the focus range of the electrons on the anode target structure is matched with the effective heat dissipation range formed by the liquid cooling pipeline, effectively reducing the local heat dissipation pressure of the target material.

[0086] In some embodiments of the present invention, Figure 1 As shown, the present application provides an X-ray source on the other hand, the X-ray source comprising: an X-ray tube as described in any of the above embodiments, an additional tube body 210 connected to one end of the extraction electrode having the cathode structure 150 of the tube body 110 of the ray tube, and a negative high-voltage plug 250 disposed inside the additional tube body 210 and located on a side away from the tube body of the ray tube and an insulator 230 disposed on a side close to the tube body of the ray tube; wherein the negative high-voltage plug 250 is used to be applied with a voltage to drive the cathode structure 150 to emit electrons; and the insulator 230 is used to suspend and fix the cathode structure 150 and the focus control electrode pair 190. In addition, the additional tube body 210 is filled with insulating oil, which can be used to ensure the insulation of the additional tube body 210.

[0087] More specifically, when the X-ray tube is used, the tube body 110 and the anode target 170 are grounded, and the external negative high voltage power supply supplies power to the cathode structure 150 through the negative high voltage plug 250, so that the cathode structure 150 emits electrons, bombarding the anode target 170 to generate X-rays. In this process, the coolant flows in and out of the liquid cooling pipe 131 in the heat dissipation structure 130 through the external pump group, takes away the heat on the anode target 170, and cools the outflowing coolant through the external device.

[0088] In a specific embodiment of the utility model, the corresponding parameters can be set to obtain an X-ray source that can work normally and continuously at a power of nearly 5kW. For example, the main parameters of the X-ray tube in this application can be that the electron beam power of the ray source is nearly 5kW, the tube voltage is 160kV, the tube current is 30mA, the cathode-anode distance is 5cm, the electron emission angle formed by the focus control electrode pair and the cathode structure is 160 degrees, the cooling water flow rate is 18L / min, the preparation material of the heat dissipation substrate is brass, the diameter of the liquid cooling pipe is 14mm, and the thickness of the tungsten target is 3mm. And after long-term continuous operation, the temperature of the anode target structure near the heat dissipation substrate is lower than 300 degrees Celsius.

[0089] Another aspect of the present invention provides an X-ray irradiation device, comprising:

[0090] The X-ray source described in the above embodiment includes a bracket structure for supporting and fixing the X-ray source, an irradiation table (for placing the irradiated object) located in the irradiation area of ​​the X-ray source, and a shielding box for preventing X-rays from leaking.

[0091] More specifically, if Figure 8 As shown in the figure, the tube body of the X-ray tube is cylindrical, the bracket structure fixes the relative position of the radiation source and the irradiation platform, and the shielding box is used to prevent X-rays from leaking outside the irradiation device. In addition, since the X-ray dose rate is related to the electron emission angle in addition to the focal distance, the irradiation platform can adopt an arc irradiation platform to ensure that the X-ray dose rate at each position is consistent. The coolant pipeline and negative high-voltage power supply are placed outside the shielding box and are not shown in the figure. Figure 8 Shown in.

[0092] The X-ray irradiation device is suitable for irradiating items including: fresh food, pre-prepared dishes, Chinese herbal medicine and other thin solids, bottled wine and other independently packaged liquids, as well as tea, spices, coffee beans and other small-volume items packed in arc-shaped containers or small packages that match the irradiation table. In order to improve the utilization rate of X-rays, the device is suitable for processing more irradiated samples at one time, rather than a small number of samples.

[0093] The utility model does not limit the shape of the ray tube body, for example, the cross section can be circular or square. In addition, the utility model does not limit the relative positions of the X-ray source, the support structure and the irradiation table in the X-ray irradiation device.

[0094] It should be clear that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of simplicity, a detailed description of the known methods is omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown, and those skilled in the art can make various changes, modifications and additions, or change the order between the steps after understanding the spirit of the present invention.

[0095] In the present invention, features described and / or illustrated for one embodiment may be used in the same manner or in a similar manner in one or more other embodiments, and / or combined with features of other embodiments or replace features of other embodiments.

[0096] The above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. For those skilled in the art, the embodiments of the utility model may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. An X-ray tube, characterized in that: include: A ray tube body, the ray tube body is used to form a closed vacuum cavity, and a cathode structure extending along a set surface and an anode target spaced apart from the cathode are arranged inside the cavity formed by the ray tube body; a heat dissipation structure, comprising a liquid cooling pipe, the heat dissipation structure being in direct or indirect contact with the anode target and being arranged on a side of the anode target away from the cathode structure, and the heat dissipation structure being welded to the ray tube body, and a portion of the ray tube body welded to the heat dissipation structure being a metal structure; A focus control electrode pair is arranged between the cathode structure and the anode target, and is used to control the movement path of electrons emitted from the cathode structure by applying a voltage between the focus control electrode pair, thereby controlling the focus range formed by the electrons emitted from the cathode structure focusing on the anode target to not exceed the effective heat dissipation range on the anode target.

2. The X-ray tube according to claim 1, characterized in that The heat dissipation structure also includes a heat dissipation substrate, which is used to cover the liquid cooling pipe and is in direct contact with the anode target to dissipate heat for the anode target.

3. The X-ray tube according to claim 2, characterized in that A temperature sensor is arranged inside or outside the heat dissipation substrate.

4. The X-ray tube according to claim 1, characterized in that The cathode structure includes one electron emitter or a plurality of electron emitters connected in parallel, each electron emitter is in the shape of a wire, a rod or a sheet, wherein the wire-shaped electron emitter is in the shape of a straight line or a spiral line.

5. The X-ray tube according to claim 4, characterized in that The cathode structure also includes an elastic stretching structure connected between one end of the electron emitter and an extraction electrode of the electron emitter, and is used for stabilizing the position of the electron emitter by stretching.

6. The X-ray tube according to claim 4, characterized in that The anode target is a plane or a curved surface, and the arrangement size of the electron emitter in each direction of the set surface is smaller than the size of the anode target in the corresponding direction.

7. The X-ray tube according to claim 1, characterized in that The X-ray tube further comprises: a grid, the grid being disposed between the cathode structure and the anode target; and / or The electron shielding structure is placed on the side of the cathode structure facing away from the anode target.

8. The X-ray tube according to claim 1, characterized in that The liquid cooling pipeline adopts a single-tube circuitous arrangement or a multi-tube shunt arrangement to form a heat dissipation surface that fits the anode target.

9. An X-ray source, characterized in that: The X-ray source comprises: An X-ray tube as claimed in any one of claims 1 to 8; and The additional tube body is connected to one end of the lead-out electrode with a cathode structure of the ray tube body, and an insulator close to the side of the ray tube body and a negative high-voltage plug located on the side away from the ray tube body are arranged inside the additional tube body.

10. An irradiation device, characterized in that: include: The X-ray source as claimed in claim 9, a support structure for fixing the X-ray source, an irradiation table located in the irradiation area of ​​the X-ray source, and a shielding box.

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