Scanning liquid-cooled X-ray transmission conversion target, electron accelerator and electronic equipment

Abstract

This invention discloses a scanning liquid-cooled X-ray transmission conversion target, an electron accelerator, and electronic equipment, relating to the field of electron accelerator technology. The key technical features include: a scanning coil, a scanning vacuum chamber, and a liquid-cooled target; the scanning coil, sleeved at the rear end of the electron beam exit window of the accelerator connected to the scanning vacuum chamber, is used to achieve two-dimensional deflection scanning of the electron beam on the target; the liquid-cooled target, installed at the front end of the scanning vacuum chamber, is used to convert the energy of the electron beam bombarding the target into X-rays; wherein, the liquid-cooled target is composed of multiple target units spliced ​​together, and the cooling channels in the target units are equipped with guides for adjusting the flow rate of the coolant in the cooling channels. This invention employs a combination of electron beam scanning and liquid cooling, reducing the temperature of the electron beam bombardment area, while simultaneously reducing the scanning frequency and the design difficulty of the scanning magnet, improving the performance of the X-ray target, and avoiding target ablation damage caused by high-power electron beam bombardment.

Description

Technical Field

[0001] This invention relates to the field of electron accelerator technology, and more specifically, to scanning liquid-cooled X-ray transmission conversion targets, electron accelerators, and electronic equipment. Background Technology

[0002] An electron accelerator is a device used to generate X-rays and is one of the most important devices in applications such as industrial irradiation, radiotherapy, security imaging, and seed breeding. Electron accelerators accelerate electrons to a target energy level (0.6–25 MeV) through methods such as radio frequency acceleration and linear induction acceleration. Electrons at the target energy bombard the target material, and through bremsstrahlung, a portion of the electron energy is converted into X-rays. The performance of the X-ray target determines the X-ray conversion efficiency, energy spectrum, and power tolerance.

[0003] Currently, X-ray conversion targets used in electron accelerators are generally fixed. Applications such as seed breeding require a high X-ray dose per unit time, with uniform irradiation of the entire seed area in a single pass. This necessitates that the X-ray target withstand high-power electron beam bombardment and ensure uniform scanning of the target area by the electron beam focus. High electron beam power can cause a rapid increase in target surface temperature, leading to ablation or even defects, thus disrupting the accelerator's vacuum state. Therefore, the accelerator's power is severely limited by target performance. Conventional scanning targets simply increase the scanning frequency to cope with the increased electron beam power; however, higher scanning frequencies place greater demands on the design and production of the scanning magnets, significantly increasing the development and production costs of the target system.

[0004] Therefore, how to research and design a scanning liquid-cooled X-ray transmission conversion target, electron accelerator, and electronic equipment that can overcome the above-mentioned defects is a problem that we urgently need to solve. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a scanning liquid-cooled X-ray transmission conversion target, an electron accelerator, and electronic equipment. By combining electron beam scanning with liquid cooling, the temperature of the electron beam bombardment zone is significantly reduced, while the scanning frequency and the design difficulty of the scanning magnet are also reduced, greatly improving the performance of the X-ray target and avoiding target ablation damage caused by high-power electron beam bombardment.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0007] In the first aspect, a scanning liquid-cooled X-ray transmission conversion target is provided, including a scanning coil, a scanning vacuum cavity and a liquid-cooled target;

[0008] The scanning coil is sleeved on the rear end corresponding to the electron beam exit window of the accelerator connected outside the scanning vacuum cavity, and is used to realize two-dimensional deflection scanning of the electron beam on the target;

[0009] The liquid-cooled target is installed at the front end of the scanning vacuum cavity and is used to convert the energy of the electron beam bombarding the target into X-rays.

[0010] The liquid-cooled target is composed of multiple target units connected to a common coolant supply end, and the cooling channel in the target unit is equipped with a guide for adjusting the flow rate of coolant in the cooling channel.

[0011] Furthermore, the guide component is a guide plate with a through hole in the middle, and the outer wall of the guide plate is sealed to the inner wall of the cooling channel.

[0012] The diameter of the through hole in the guide plate is determined by thermal and fluid simulation analysis based on the position of the target unit where the guide plate is located. The thermal and fluid simulation analysis ensures that the temperature fluctuation between each target unit does not exceed the preset value when the electron beam power changes within the preset power range and during the scanning process.

[0013] Furthermore, the end of the guide plate near the liquid inlet copper pipe in the cooling channel is flat.

[0014] Furthermore, the end of the guide plate near the target inlet end in the cooling channel has an inner conical surface.

[0015] Furthermore, the flow guide includes an inlet limiting ring, an outlet limiting ring, and a movable plate. The inlet limiting ring and the outlet limiting ring are installed alternately inside the cooling channel, and the movable plate is located between the inlet limiting ring and the outlet limiting ring.

[0016] The outlet limiting ring is embedded with a honeycomb grid, and the grid holes in the honeycomb grid are movably connected to a movable rod arranged along the axis of the cooling channel. One end of the movable rod is fixedly connected to the movable plate.

[0017] The movable rod is fitted with a spring, one end of which is fixedly connected to the movable plate, and the other end of which is fixedly connected to the honeycomb grid.

[0018] Furthermore, the scanning vacuum chamber is equipped with a water-cooling pipe.

[0019] Furthermore, the water-cooling tube is arranged in a folded manner inside the scanning vacuum chamber, with the inlet end of the water-cooling tube extending from the front side of the scanning vacuum chamber and the outlet end of the water-cooling tube extending from the rear side of the scanning vacuum chamber.

[0020] Furthermore, the scanning vacuum cavity is either horn-shaped with a rounded rear and a large front, or a triangular trapezoid with a smaller rear and a larger front.

[0021] In a second aspect, an electron accelerator is provided, comprising an accelerator that emits an electron beam and a scanning liquid-cooled X-ray transmission conversion target as described in the first aspect.

[0022] Thirdly, an electronic device is provided, comprising at least one electron accelerator as described in the second aspect.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The scanning liquid-cooled X-ray transmission conversion target proposed in this invention adopts a combination of electron beam scanning and liquid cooling, which greatly reduces the temperature of the electron beam bombardment area, while reducing the scanning frequency and the design difficulty of the scanning magnet, greatly improving the performance of the X-ray target and avoiding the ablation damage to the conversion target caused by high-power electron beam bombardment.

[0025] 2. Through thermal and fluid simulation analysis, this invention flexibly designs through holes of appropriate diameter for the guide plates in the target units at different locations. This ensures that when the electron beam power varies within a preset power range and the temperature fluctuation between each target unit during the scanning process does not exceed the preset value, thus enhancing the stability and reliability of X-ray transmission conversion target applications. At the same time, it can be applied to electron beams with a wider range of power and can be adjusted according to the electron beam status on site, thus having a certain degree of versatility.

[0026] 3. In this invention, the end of the guide plate near the liquid inlet end of the target in the cooling channel is an inner conical surface, which can reduce the generation of air cannons and effectively prevent the situation where bubbles cannot be discharged.

[0027] 4. The present invention also achieves the adjustment of the size of the pores in the cooling channel that allow coolant to flow by balancing the coolant pressure and elasticity in the cooling channel, which is more flexible, versatile and adaptable. Attached Figure Description

[0028] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0029] Figure 1 This is a schematic diagram of the overall structure of the conversion target in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the internal structure of the conversion target in an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of a flow guide component in one embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of another structure of the flow guide in an embodiment of the present invention;

[0033] The attached diagram shows the markings and corresponding component names:

[0034] 1. Scanning coil; 2. Scanning vacuum chamber; 3. Liquid-cooled target; 4. Target unit; 5. Cooling channel; 6. Water-cooled pipe; 7. Vacuum extraction port; 8. Liquid inlet copper pipe; 9. Target liquid inlet end; 10. Guide plate; 11. Inlet limiting ring; 12. Outlet limiting ring; 13. Movable plate; 14. Movable rod; 15. Spring; 16. Honeycomb grid. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0036] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly or indirectly attached to that other component. When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to that other component.

[0037] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0038] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0039] Example: Scanning liquid-cooled X-ray transmission conversion target, such as Figure 1 and Figure 2As shown, the system includes a scanning coil 1, a scanning vacuum chamber 2, and a liquid-cooled target 3. The scanning coil 1 is fitted onto the rear end of the electron beam exit window of the accelerator connected to the scanning vacuum chamber 2, and is used to achieve two-dimensional deflection scanning of the electron beam on the target. The liquid-cooled target 3 is installed at the front end of the scanning vacuum chamber 2, and is used to convert the energy of the electron beam bombarding the target into X-rays. The liquid-cooled target 3 is composed of multiple target units 4 connected to a common coolant supply end. The cooling channels 5 in the target units 4 are equipped with guides for adjusting the flow rate of the coolant in the cooling channels 5.

[0040] This invention employs a combination of electron beam scanning and liquid cooling, which significantly reduces the temperature of the electron beam bombardment zone, while also reducing the scanning frequency and the design complexity of the scanning magnet. This greatly improves the performance of the X-ray target and avoids target ablation damage caused by high-power electron beam bombardment.

[0041] In this embodiment, a water-cooled pipe 6 is disposed inside the scanning vacuum chamber 2. The water-cooled pipe 6 is arranged in a folded manner inside the scanning vacuum chamber 2, with its inlet end extending from the front side of the scanning vacuum chamber 2 and its outlet end extending from the rear side of the scanning vacuum chamber 2. Furthermore, the scanning vacuum chamber 2 is either a trumpet shape with a rounded rear and a large front, or a triangular trapezoid with a smaller rear and a larger front.

[0042] A high-energy electron beam (A) enters the target cavity through scanning coil 1 or deflecting magnet, and performs two-dimensional scanning on the liquid-cooled target 3 under the action of scanning coil 1 or deflecting magnet. The generated X-rays exit through the window into the working area. Part of the heat deposited on the target is absorbed and dissipated through thermal radiation in the cavity, and the other part is conducted to the coolant through heat sinks and cavity walls.

[0043] It should be noted that the working target material includes, but is not limited to, tungsten, tantalum, molybdenum, and alloy materials, such as leylene tungsten alloy. The interaction between the electron beam and the target atoms results in part of the energy being converted into photons (X-rays) and transmitted, while the other part is converted into heat energy and dissipated. The bottom of the working target is a cooling device, consisting of a cooling channel 5, a flow guide, and a main body. The coolant is typically deionized water, but other liquids with good flowability and thermal conductivity, such as silicone oil, can also be used. The flow guide acts as a flow guide, controlling the flow direction and proportion of the coolant. The cooling main body is made of a material with good thermal conductivity, such as copper. The cooling components and target material are fixed to the liquid-cooled cavity wall, which simultaneously assembles several target units 4 into a large target. The cavity wall is made of a material with high mechanical strength, good machinability, and easy welding, such as stainless steel. Adjacent target units 4 are sealed by welding, such as argon arc welding or laser welding. To ensure vacuum leakage rate and reliability, both the working end and the cold end require sealed welding.

[0044] Thermal management of the liquid-cooled target 3 is one of the core aspects of the target design. The heat input port is the high-power electron beam generated by the accelerator, and the heat output ports are the target coolant and the cavity wall cooling water. The heat conversion process occurs during electron beam blasting. A portion of the heat is converted into X-ray energy: through Monte Carlo simulations of electron beams of different energies and different target materials, the conversion efficiency is generally around 5-30%. Most of the heat is absorbed by the target material, with a deposition efficiency of approximately 50-70%. This portion of heat is conducted through lateral conduction and target body conduction, causing the target body temperature to rise, and is absorbed and carried away by the target body coolant (mainly) and the cavity cooling water (a small portion). The remaining energy is radiated onto the cavity through thermal radiation, causing the cavity temperature to rise, and the excess is carried away by the cavity cooling water. Therefore, during the thermal management simulation design, it is necessary to combine the engineering design, adjust the design and water flow rate of the cavity water-cooling pipe 6, and, more importantly, optimize the target cooling channel 5 and the type and flow rate of the coolant.

[0045] As an optional implementation method, such as Figure 3 As shown, the flow guide is a flow guide plate 10 with a through hole in the middle. The outer wall of the flow guide plate 10 is sealed to the inner wall of the cooling channel 5. The diameter of the through hole in the flow guide plate 10 is determined by thermal and fluid simulation analysis based on the position of the target unit 4 where the flow guide plate 10 is located. The thermal and fluid simulation analysis ensures that the temperature fluctuation between each target unit 4 does not exceed the preset value when the electron beam power changes within the preset power range and during the scanning process.

[0046] The end of the guide plate 10 near the liquid inlet copper pipe 8 in the cooling channel 5 is a flat surface, and the end of the guide plate 10 near the target liquid inlet end 9 in the cooling channel 5 is an inner conical surface.

[0047] It should be noted that the inlet copper pipe 8 is welded to the inlet end of the target. The guide plate 10 has an overall shape similar to a column with a hole in the middle; its shape can be cylindrical or square, and the number and diameter of the holes depend on the required flow rate. The bottom of the front end of the guide plate 10 is ground flat to facilitate the welding of the inlet copper pipe 8. The area near the holes of the guide plate 10 needs to be rounded and then polished smooth. The diameter of the holes at the rear end of the guide plate 10 gradually increases until it matches the inlet end 9 of the target, preventing air bubbles from being trapped. For a single-hole guide plate 10, the size of the opening directly determines the flow rate, which is related to the position of the guide plate 10 in the target unit 4, and is given through thermal and fluid simulations.

[0048] In general, multiple target units 4 in a liquid-cooled target 3 are connected to a single coolant supply end. Therefore, the internal hydraulic pressure of target units 4 at different positions is different. The aperture design of the guide plate 10 in this invention enables the cooling target to be suitable for electron beams with a wider range of power and can be adjusted according to the electron beam status on site, thus having a certain degree of versatility.

[0049] As another alternative implementation method, such as Figure 4As shown, the flow guide includes an inlet limiting ring 11, an outlet limiting ring 12, and a movable plate 13. The inlet limiting ring 11 and the outlet limiting ring 12 are installed at intervals inside the cooling channel 5, and the movable plate 13 is located between the inlet limiting ring 11 and the outlet limiting ring 12. A honeycomb grid 16 is embedded in the outlet limiting ring 12. The grid holes in the honeycomb grid 16 are movably connected to a movable rod 14 arranged along the axis of the cooling channel 5. One end of the movable rod 14 is fixedly connected to the movable plate 13. A spring 15 is sleeved on the movable rod 14. One end of the spring 15 is fixedly connected to the movable plate 13, and the other end of the spring 15 is fixedly connected to the honeycomb grid 16.

[0050] It should be noted that when the coolant pressure in the cooling channel 5 is too low, the movable plate 13 will contact the inlet limiting ring 11 under the elastic force of the spring 15, which can achieve complete blockage of the cooling channel 5. However, when the coolant pressure is too high and does not exceed the elastic deformation limit of the spring 15, the movable plate 13 will compress the spring 15 and maintain a certain gap with the outlet limiting ring 12.

[0051] The present invention also achieves the adjustment of the size of the pores in the cooling channel 5 that allow coolant to flow by balancing the coolant pressure and elasticity in the cooling channel 5, which is more flexible, versatile and adaptable.

[0052] The aforementioned scanning liquid-cooled X-ray transmission conversion target can be applied in fields such as industrial irradiation, radiotherapy, security imaging, and seed breeding.

[0053] Working Principle: This invention employs a combination of electron beam scanning and liquid cooling, significantly reducing the temperature of the electron beam bombardment zone. This also reduces the design complexity of the scanning frequency and scanning magnet, greatly improving the performance of the X-ray target and preventing target ablation damage caused by high-power electron beam bombardment. Furthermore, through thermal and fluid simulation analysis, this invention flexibly designs through-holes of appropriate diameters for the guide plates 10 in target units 4 at different locations. This ensures that temperature fluctuations between target units 4 do not exceed preset values ​​when the electron beam power varies within a preset range, and during scanning. This enhances the stability and reliability of X-ray transmission conversion target applications and is applicable to a wider range of electron beam power. It can be adjusted according to the on-site electron beam conditions, exhibiting a degree of versatility. Additionally, this invention achieves adjustment of the size of the pores in the cooling channel 5 that allow coolant flow by balancing the coolant pressure and elasticity, resulting in greater flexibility, versatility, and adaptability.

[0054] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A scanning liquid-cooled X-ray transmission conversion target, characterized in that, It includes a scanning coil (1), a scanning vacuum chamber (2), and a liquid-cooled target (3); The scanning coil (1) is sleeved on the rear end corresponding to the electron beam exit window of the accelerator connected outside the scanning vacuum cavity (2) to realize two-dimensional deflection scanning of the electron beam on the target; The liquid-cooled target (3) is installed at the front end of the scanning vacuum chamber (2) and is used to convert the energy of the electron beam bombarding the target into X-rays; The liquid-cooled target (3) is composed of multiple target units (4) connected to a common coolant supply end. The cooling channel (5) in the target unit (4) is provided with a guide for adjusting the flow rate of coolant in the cooling channel (5).

2. The scanning liquid-cooled X-ray transmission conversion target according to claim 1, characterized in that, The guide component is a guide plate (10) with a through hole in the middle, and the outer wall of the guide plate (10) is sealed to the inner wall of the cooling channel (5). The diameter of the through hole in the guide plate (10) is determined by thermal and fluid simulation analysis based on the position of the target unit (4) where the guide plate (10) is located. The thermal and fluid simulation analysis ensures that the temperature fluctuation between each target unit (4) does not exceed the preset value when the electron beam power changes within the preset power range and during the scanning process.

3. The scanning liquid-cooled X-ray transmission conversion target according to claim 2, characterized in that, The end of the guide plate (10) near the liquid inlet copper pipe (8) in the cooling channel (5) is flat.

4. The scanning liquid-cooled X-ray transmission conversion target according to claim 2, characterized in that, The end of the guide plate (10) near the target liquid inlet end (9) in the cooling channel (5) is an inner conical surface.

5. The scanning liquid-cooled X-ray transmission conversion target according to claim 1, characterized in that, The flow guide includes an inlet limiting ring (11), an outlet limiting ring (12), and a movable plate (13). The inlet limiting ring (11) and the outlet limiting ring (12) are installed at intervals inside the cooling channel (5), and the movable plate (13) is located between the inlet limiting ring (11) and the outlet limiting ring (12). The outlet limiting ring (12) is embedded with a honeycomb grid (16), and the grid holes in the honeycomb grid (16) are movably connected to a movable rod (14) arranged along the axis of the cooling channel (5). One end of the movable rod (14) is fixedly connected to the movable plate (13). The movable rod (14) is fitted with a spring (15), one end of the spring (15) is fixedly connected to the movable plate (13), and the other end of the spring (15) is fixedly connected to the honeycomb grid (16).

6. The scanning liquid-cooled X-ray transmission conversion target according to claim 1, characterized in that, The scanning vacuum chamber (2) is equipped with a water-cooling pipe (6).

7. The scanning liquid-cooled X-ray transmission conversion target according to claim 6, characterized in that, The water-cooled tube (6) is arranged in a folded manner inside the scanning vacuum chamber (2). The inlet end of the water-cooled tube (6) extends from the front side of the scanning vacuum chamber (2), and the outlet end of the water-cooled tube (6) extends from the rear side of the scanning vacuum chamber (2).

8. The scanning liquid-cooled X-ray transmission conversion target according to claim 1, characterized in that, The scanning vacuum cavity (2) is either a trumpet shape with a rounded rear and a large front, or a triangular trapezoid with a smaller rear and a larger front.

9. An electron accelerator, characterized in that, It includes an accelerator that emits an electron beam and a scanning liquid-cooled X-ray transmission conversion target as described in any one of claims 1-8.

10. An electronic device, characterized in that, Includes at least one electron accelerator as described in claim 9.

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