X-ray source and high-speed track detection method based on X-ray

Abstract

The present invention discloses an X-ray source and a high-speed track detection method based on X-rays. The X-ray source includes a linear radio frequency accelerator for generating an electron beam and a rotating target for generating X-rays. The linear radio frequency accelerator replaces the traditional DC high-voltage X-ray tube. The electron beam bombards the rotating target by grazing incidence reflection to generate X-rays. The interior of the accelerator tube is a vacuum chamber, and the rotating target is arranged outside the vacuum. On the basis of placing the rotating target outside the vacuum chamber, the rotating target is directly cooled. In conjunction with a collimated detector array arranged along the rail, the X-ray generating device can be used for high-speed track detection. The detection method includes the following steps: generating an electron beam by a linear radio frequency accelerator; the electron beam bombards the rotating target to generate X-rays; the X-rays penetrate the rail and are received by the collimated detector array to obtain a defect signal inside the rail.

Description

Technical Field

[0001] The present invention belongs to the field of X-ray nondestructive testing, and in particular relates to an X-ray source and a high-speed track detection method based on X-rays. Background Art

[0002] X-ray sources are widely used in industrial inspection, scientific instrumentation, medical imaging, and treatment. In industrial imaging applications, the electron beam from the X-ray source bombards the target material, generating X-rays that penetrate the object, carrying density information and being received by the detector. In many applications, such as armor-piercing and non-destructive imaging of high-speed rail tracks, X-ray imaging faces significant challenges: Conventional X-rays are insufficient to penetrate large, high-density metal objects, requiring ultra-hard X-rays with a force of 0.6 MV or higher to obtain clear images. Furthermore, the object is in high-speed motion, requiring a sufficiently high X-ray dose to achieve millimeter-level or higher resolution. Since most of the electron beam power is ultimately deposited in the target material as heat, excessive beam power can melt the target.

[0003] To reduce the power density in the target material and improve the heat dissipation rate, rotating target technology is currently generally used. When the power is relatively low and the electron beam energy is high (approximately 10MV and above), the use of a small-focus rotating transmission target is feasible. However, the transmission target cannot utilize the projection effect of the target angle to disperse the electron beam power. Even if a rotating transmission target is used, it cannot be used at too high a power. Moreover, the heat dissipation requirements and mechanical strength of the transmission target at high power dictate that the target needs to be of a certain thickness. Since the target is made of a high atomic number material, the target also results in a significant loss of X-ray dose.

[0004] However, for high-power electron beams, a transmission target has a limited beam focal size, and excessive power density can melt the target disk. Rotating reflective targets are generally used, leveraging the projection effect of the reflection angle to significantly reduce the target surface power density. However, as the electron beam energy in the X-ray tube increases further, for example, to above 0.6MV or even up to 10MV, the X-ray dose distribution generated by target shooting exhibits significant angular non-uniformity. Traditional vertical reflective beam emission (where the electron beam and X-ray beam directions are perpendicular) results in low X-ray utilization, thereby increasing the target's equivalent heat load.

[0005] On the other hand, in order to improve penetration, the X-ray energy needs to be increased, but ordinary DC high-voltage X-ray tubes and their power sources face great difficulties in high-voltage insulation. Generally, the high voltage output of the DC high-voltage power supply for X-rays does not exceed 0.6MV. A few technical routes can achieve the level of 3MV, but the volume is very large and usually requires a large room for installation.

[0006] Therefore, it is extremely difficult to realize a portable high-power, small-spot ultra-hard X-ray source, and there are currently no corresponding technical methods and products. Summary of the Invention

[0007] On the one hand, in order to meet the demand for higher X-ray penetration, the present application provides an X-ray source, including a linear radio frequency accelerator for generating an electron beam and a rotating target for generating X-rays; the linear radio frequency accelerator replaces the traditional DC high-voltage X-ray tube, and the linear radio frequency acceleration method replaces the traditional DC high-voltage acceleration method, thereby improving the ray penetration ability and conversion efficiency, and greatly reducing the size of the power system and the danger of high voltage.

[0008] The linear radio frequency accelerator includes an accelerating tube, an electron gun connected to the accelerating tube, and a magnetron connected to the accelerating tube. The electron gun emits electrons, and the magnetron, driven by a magnetron power supply, generates 50-100kW high-power microwaves. The electrons are accelerated by the high-power microwaves in the accelerating tube to form an electron beam with a power of 0.6-25 MV.

[0009] To avoid damage caused by high power density on the target and further improve heat dissipation efficiency and radiation dose, the above scheme is further improved by: the electron beam bombards the rotating target using grazing incidence reflection to generate X-rays. That is, it bombards the cylindrical target surface of the rotating target at a very small angle, forming a long strip of electron beam spot, which reduces the electron beam power density on the target by an order of magnitude. After the electron beam bombards the target surface, X-rays are generated. Only X-rays within a very small angle with the electron beam direction can enter the collimated detector after penetrating the rails. This utilizes the X-ray flux at a small angle when the electron energy is high, which is the highest, and also avoids target absorption of the radiation dose. Furthermore, the angle of grazing incidence of the electron beam is 1-20 degrees. The X-ray angle used is 0-30 degrees. The electron beam energy generated by the linear radio frequency accelerator is greater than 0.6MV. The higher the electron beam energy, the better the forward performance of the X-rays. The grazing incidence reflection target emission method combines the advantages of the reflective target fully utilizing the target angle dispersion power density and the advantage of the transmissive target fully utilizing the maximum forward dose, without the disadvantage of radiation dose absorption by the transmissive target.

[0010] In order to improve the heat dissipation efficiency of the rotating target, based on the above solution, there is a further feature: the interior of the accelerating tube is a vacuum chamber, and the rotating target is arranged outside the vacuum; the electron beam penetrates the electron transmission window of the accelerating tube and bombards the rotating target in the air, and the material of the electron transmission window is a low-Z material, including but not limited to diamond, beryllium, diamond-copper alloy, titanium film, etc.

[0011] The rotating target is placed outside the vacuum chamber and directly cooled. Using air or liquid cooling devices to efficiently dissipate heat through convection or super-evaporation on the rotating target surface overcomes the disadvantage that heat in a vacuum can only be dissipated through radiation and long-distance conduction. Surface-enhanced radiation technology is also used to further improve heat dissipation efficiency.

[0012] my country's rapidly growing operating mileage, increasing speeds, and increasing density are driving higher demands for transportation safety technologies. Rail track damage can lead to serious loss of life and property. Rapid, nondestructive detection of track damage can significantly improve railway efficiency. Existing technology uses X-rays to detect internal rail defects, improving efficiency and reducing operating costs.

[0013] Although X-ray inspection has the potential to significantly increase the speed of rail inspection, the current X-ray generation methods struggle to meet the power and energy requirements of X-ray tubes for high-speed rail inspection. Because rails are thick, typical industrial X-ray tubes for nondestructive testing (NDT) can only deliver energies of 160-450kV, making them unable to penetrate the rails. To identify internal defects, the X-ray dose after penetration must be strong enough for the detector to generate a signal with a high signal-to-noise ratio, effectively identifying the defects. However, the maximum power of current industrial X-ray tubes is typically only around 4.5kW, insufficient for this application. Achieving a spatial resolution of 1-3mm requires a very small X-ray equivalent focal spot. At higher powers, the X-ray conversion target would be severely damaged, and the fixed conversion targets currently used in industrial X-ray tubes cannot meet this requirement.

[0014] To improve penetration, X-ray energy needs to be further increased. However, conventional DC high-voltage X-ray tubes and their power units face significant difficulties with high-voltage insulation. As the electron beam energy in an X-ray tube increases, the X-ray flux exhibits significant directionality. The reflective targets used in industrial tubes for heat dissipation cannot utilize the maximum X-ray flux. While using a transmission target can address this issue, they cannot utilize the target angle to disperse the electron beam power. Even with a rotating transmission target, excessive power cannot be used. Furthermore, the heat dissipation requirements and mechanical strength of the transmission target at high power dictate that it must be of a certain thickness, which can also result in loss of X-ray dose.

[0015] Based on this, the present application also provides an X-ray-based high-speed rail inspection method, which uses the above-mentioned X-ray source to detect high-speed rail defects and also includes a collimated detector array set along the rails, greatly improving the inspection and maintenance efficiency of high-speed rail. The method specifically includes the following steps:

[0016] T1: Produce 0.6-25 MV electron beam by linear radio frequency accelerator;

[0017] T2: Electron beam bombardment produces X-rays on a rotating target;

[0018] T3: After penetrating the rails, the X-rays are received by the collimated detector array, obtaining internal rail defect signals.

[0019] Based on the above solution, further steps are as follows: after the electron beam in step T2 passes through the vacuum window, it bombards the rotating target in a grazing incidence manner to generate X-rays, and the reflected X-rays in a small angle range are used for imaging.

[0020] Based on the above solution, the rotating target is fixed to the train wheel via a heat-insulating support rod. The train's own speed drives the rotating target, simplifying the rotating target drive technology, solving the need for rotating target cooling, and reducing the impact of heat from the target on the wheel. The rotating target in step T2 is driven by a motor or wheel.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0022] 1. The present invention uses a linear radio frequency accelerator and a rotating target to generate X-rays, which can improve the ray penetration ability and conversion efficiency, greatly improving the penetration of X-rays.

[0023] 2. The present invention proposes a grazing-incidence reflective rotating target technology to maximize the utilization of ultra-hard (above 0.6MV) X-ray power, which not only significantly reduces the electron beam power density on the target surface, but also maximizes the utilization of the maximum X-ray flux of the medium-energy electron beam and avoids the target's absorption of the dose.

[0024] 3. The present invention uses a linear radio frequency accelerator to replace the traditional DC high-voltage X-ray tube to generate an electron beam with an energy of 0.6-25MV, which greatly reduces the size of the power system and the high voltage danger.

[0025] 4. Based on the fact that the electron beam energy is sufficient to penetrate the window material, the present invention adopts direct cooling target technology and two heat dissipation structures: a rotating target in a vacuum and an external direct cooling rotating target. This greatly improves the heat dissipation efficiency of the target under high-power electron beam bombardment; the separation of the target and the accelerating tube greatly reduces the process, debugging difficulty and quality cost compared to the integrated closed accelerating tube-target assembly.

[0026] 5. The present invention proposes a wheel-driven rotating target technology, which is simpler and more reliable than the electrode-driven technology.

[0027] 6. The present invention applies an X-ray source to high-speed track inspection to achieve the purpose of improving the speed of internal defect detection of railway tracks. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the examples. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be considered as limiting the scope. A person of ordinary skill in the art can also derive other relevant drawings based on these drawings without inventive effort. In the drawings:

[0029] Figure 1 Schematic diagram of the device structure of Example 1-2;

[0030] Figure 2 This is a partial schematic diagram of the device structure of Example 3;

[0031] Figure 3 Schematic diagram of the device structure of Example 4;

[0032] Figure 4 This is a partial schematic diagram of the device structure of Example 4.

[0033] The symbols and corresponding component names in the accompanying drawings are: 01-electron gun, 02-magnetron, 03-accelerator tube, 04-magnetron power supply, 05-electron gun power supply, 06-control system, 07-rotating target, 08-rotor drive power supply, 09-cooling system, 10-wheel, 11-collimation detector array, 12-rail, 13-electron transmission window, 14-thermal insulation support rod, 15-high thermal conductivity bearing.

[0034] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0035] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0036] Throughout this specification, references to "one embodiment," "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Therefore, appearances of the phrases "one embodiment," "an embodiment," "an example," or "an example" in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in one or more embodiments or examples in any suitable combinations and / or subcombinations. Furthermore, it will be understood by those of ordinary skill in the art that the figures provided herein are for illustrative purposes only and are not necessarily drawn to scale. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0037] In the description of the present invention, the terms "front", "back", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships 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 direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the scope of protection of the present invention.

[0038] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0039] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0040] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0041] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1A step that specifies a function in one or more boxes.

[0042] Those skilled in the art will understand that all or part of the steps in implementing the above facts and methods can be completed by instructing relevant hardware through a program, and the program involved or the program can be stored in a computer-readable storage medium. When the program is executed, it includes the following steps: the corresponding method steps are then brought out, and the storage medium can be ROM / RAM, a disk, an optical disk, etc.

[0043] Example 1:

[0044] like Figure 1 As shown, in this embodiment, an X-ray source is applied to high-speed rail inspection, including a linear radio frequency accelerator for generating an electron beam, a rotating target 07 for generating X-rays, and a collimated detector array 11; the linear radio frequency accelerator replaces the traditional DC high-voltage X-ray tube, and the linear radio frequency acceleration method replaces the traditional DC high-voltage acceleration method, thereby improving the radiation penetration ability and conversion efficiency, and greatly reducing the size of the power system and the danger of high voltage.

[0045] The linear radio frequency accelerator includes an accelerating tube 03, an electron gun 01 connected to the accelerating tube 03, and a magnetron 02 connected to the accelerating tube 03; the electron gun 01 emits electrons under the drive of an electron gun power supply 05, and the magnetron 02 generates 50-100kW high-power microwaves under the drive of a magnetron power supply 04. The electrons are accelerated by the high-power microwaves in the accelerating tube 03 to form an electron beam of 0.6-25MV.

[0046] Example 2:

[0047] like Figure 1 As shown, based on Example 1, the electron beam uses grazing incidence reflection to bombard the rotating target 07 to generate X-rays. Both the accelerator tube 03 and the rotating target 07 are located in a vacuum chamber. The electron beam strikes the cylindrical target surface of the rotating target 07 at a very small angle, forming a long strip of electron beam spot, which reduces the electron beam power density on the target by an order of magnitude. After the electron beam strikes the target surface, X-rays are generated. Only X-rays within a very small angle with the electron beam direction can enter the collimated detector after penetrating the rails 12. This utilizes the X-ray flux, which is highest at small angles when the electron energy is high, and also prevents target absorption of the dose. The electron beam grazing incidence angle is 1-20 degrees. The X-ray angle used is 0-30 degrees. The electron beam energy generated by the linear radio frequency accelerator is greater than 0.6MV. The higher the electron beam energy, the better the forward direction of the X-rays. The grazing incidence reflection target emission method combines the advantages of the reflective target's full utilization of the target's angular dispersion power density with the advantage of the transmissive target's maximum forward dose, without the disadvantage of radiation dose absorption by the transmissive target.

[0048] Example 3:

[0049] like Figure 2 As shown, based on Example 2, the interior of the accelerating tube 03 is a vacuum chamber, and the rotating target 07 is arranged outside the vacuum chamber. The rotating target 07 is connected to the motor drive device through a high thermal conductivity bearing 15 and a heat-insulating support rod 14. The rotating target 07 works under the drive of the rotor drive power supply 08; the electron beam penetrates the electron transmission window 13 of the accelerating tube 03 and then bombards the rotating target 07 in the air. The material of the electron transmission window 13 is a low-Z material, including but not limited to diamond, beryllium, diamond-copper alloy, titanium film, etc.

[0050] Based on the placement of the rotating target 07 outside the vacuum chamber, the rotating target 07 is directly cooled. High-speed airflow or high-speed water flow from the cooling system 09 efficiently convects or super-evaporates the working surface and end face of the rotating target 07, overcoming the disadvantage that heat in a vacuum can only be dissipated through radiation and long-distance conduction. Surface-enhanced radiation technology is also used to further improve heat dissipation efficiency. Based on the fact that the electron beam energy is sufficient to penetrate the window material, direct-cooling target technology is used to greatly improve the heat dissipation efficiency of the target under high-power electron beam bombardment. The separation of the target and the accelerating tube 03 significantly reduces the difficulty of process and debugging, as well as quality costs, compared to an integrated, enclosed accelerating tube 03-target assembly. At the same time, the control system 06 is connected to the drive power supplies of each joint and the cooling system 09, enabling coordinated control of the working status of each unit and the collection of relevant data.

[0051] Example 4:

[0052] like Figure 3 and Figure 4 As shown, on the basis of Example 3, the rotating target 07 is fixed to the train wheel 10 through the heat-insulating support rod 14, and the wheel 10 is passively driven instead of the motor actively driven. The rotating target 07 is driven by the speed of the train itself, which simplifies the driving technology of the rotating target 07 and solves the cooling requirement of the rotating target 07. At the same time, it reduces the influence of the heat on the target on the wheel 10. Compared with the electrode driving technology, it is simpler and more reliable.

[0053] Example 5:

[0054] Based on Example 4, this embodiment provides an X-ray-based high-speed track detection device and method, including the following steps:

[0055] T1: Produce 0.6-25 MV electron beam by linear radio frequency accelerator;

[0056] T2: The electron beam bombards the rotating target 07 to generate X-rays;

[0057] T3: After penetrating the rail 12 , the X-rays are received by the collimated detector array 11 , and internal defect signals of the rail 12 are obtained.

[0058] By combining a linear radio frequency accelerator with grazing incidence-reflection rotating target technology, and adopting two heat dissipation structures, namely a rotating target in a vacuum and an external direct-cooling rotating target, internal defect detection of high-speed rail tracks can be achieved within the optimal X-ray energy range (electron beam energy 0.6-25MV) and higher power (electron beam power 6-50kW) required for railway track inspection, thereby improving the speed of track maintenance.

[0059] The specific implementation methods described above further explain in detail the purpose, technical solutions and beneficial effects of the present invention. 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 equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An X-ray source, characterized in that: It includes a linear radio frequency accelerator for generating electron beams and a rotating target for generating X-rays; The linear radio frequency accelerator includes an accelerating tube, an electron gun connected to the accelerating tube, and a magnetron connected to the accelerating tube; the electron beam bombards the rotating target in a grazing incidence reflection manner to generate X-rays; The interior of the accelerating tube is a vacuum chamber, and the rotating target is arranged outside the vacuum chamber; the electron beam penetrates the electron transmission window of the accelerating tube and bombards the rotating target in the air.

2. An X-ray source according to claim 1, characterized in that: The angle of the electron beam grazing incidence is 1-20 degrees, and the angle of the reflected X-ray used is 0-30 degrees.

3. The X-ray source according to claim 1, wherein: The electron transmission window is made of low-Z material.

4. The X-ray source according to claim 1, wherein: The rotating target surface is directly cooled by an air cooling device or a liquid cooling device.

5. A high-speed rail inspection method based on X-rays, using an X-ray source according to any one of claims 1 to 4 to detect high-speed rail defects, characterized in that: The invention also includes a collimating detector array arranged along the rails; specifically, the steps include: T1: Produce 0.6-25 MV electron beam by linear radio frequency accelerator; T2: Electron beam bombardment produces X-rays on a rotating target; T3: After penetrating the rails, the X-rays are received by the collimated detector array, obtaining internal rail defect signals.

6. The X-ray-based high-speed rail detection method according to claim 5, characterized in that: After the electron beam in step T2 passes through the vacuum window, it bombards the rotating target in a grazing incidence manner to generate X-rays, and the reflected X-rays in a small angle range are used for imaging.

7. The X-ray-based high-speed rail inspection method according to claim 5, characterized in that: The rotating target is fixed on the train wheel through the heat-insulating support rod, and the rotating target is driven to rotate by the train's own speed.

8. The X-ray-based high-speed rail inspection method according to claim 5, characterized in that: The rotating target in step T2 is driven by a motor.

Images