Magnetic field focusing correction electron beam acceleration system and method

Abstract

The invention discloses a magnetic field focusing correction electron beam acceleration system, which comprises a nano composite cathode material for an electron gun and structure optimization control emission, the accelerating tube is multi-stage, adjustable in resonant frequency and provided with a collimating device; the focusing coil is superconductively wound, the magnetic field is excellent, and the intensity is adjustable; the correction coil is independently controlled by a plurality of three-dimensional sub-coils; the control system comprises a sensor and the like, focusing and correction of the electron beam are achieved based on intelligent control of machine learning, all parts work cooperatively to ensure that the electron beam is kept in a good state in the acceleration process, and the requirements of various application scenes are met, such as the high-precision control requirement of the electron beam in the fields of electron microscopes, electron beam lithography and the like. According to the invention, electron beam high-precision control, high-efficiency acceleration, stable energy, accurate focusing and correction, intelligent self-adaption of a control system are realized, beam quality is improved, continuous optimization of system performance and reliable operation are guaranteed, and multi-field development is promoted.

Description

Technical Field

[0001] The invention relates to the technical field of electron beam acceleration systems, and in particular to a magnetic field focusing and correction electron beam acceleration system and method. Background Art

[0002] In the field of modern science and technology, electron beam acceleration technology is widely used in many aspects, such as electron microscopy, electron beam lithography, radiation therapy, material modification, etc. With the continuous development of these application fields, the performance requirements of electron beams are increasing, especially in terms of energy stability, focusing accuracy and beam quality of electron beams.

[0003] In electron microscopy, high-resolution imaging relies on a highly focused and energy-stable electron beam to clearly distinguish microscopic structures; electron beam lithography requires the electron beam to have precise focusing and positioning capabilities to achieve nanometer-level processing accuracy, which is essential for high-tech industries such as semiconductor chip manufacturing. In the field of radiation therapy, an accurately focused electron beam can accurately deliver radiation energy to diseased tissue while minimizing damage to surrounding healthy tissue.

[0004] However, traditional electron beam acceleration systems face many challenges in practical applications. On the one hand, the initial characteristics of the electron beam emitted by the electron gun are difficult to accurately control, such as the emission angle and initial divergence, which will affect the subsequent acceleration and focusing effects. On the other hand, during the acceleration process of the accelerating tube, there are limitations in the performance optimization of the microwave resonant cavity, resulting in low electron beam acceleration efficiency and poor energy stability.

[0005] The uniformity and adjustment accuracy of the magnetic field generated by the focusing coil are insufficient to meet the increasing focusing requirements, which easily causes the electron beam to defocus during transmission and affects the beam quality. The design of the correction coil is not flexible and precise enough to effectively deal with the dynamic changes of the electron beam during acceleration, and it is impossible to correct in real time the problem of the electron beam deviating from the ideal trajectory due to various factors (such as space charge effect, relativistic effect, etc.).

[0006] In addition, traditional control systems lack the ability to accurately predict and adaptively adjust the behavior of electron beams, and can only use relatively fixed control strategies, which are difficult to adapt to different application scenarios and complex and changeable electron beam states. This makes it impossible for the system to effectively adjust the focusing and acceleration process of the electron beam in a timely manner when faced with various interference factors, thus limiting the performance improvement of the entire electron beam acceleration system.

[0007] Therefore, there is an urgent need for an innovative magnetic field focusing correction electron beam acceleration system and method, which can overcome the shortcomings of the existing technology, achieve more precise control and optimization of the electron beam, meet the strict requirements of modern scientific and technological development on electron beam performance, and promote further development of related fields. The present invention is proposed based on this background, and aims to provide a high-performance and high-reliability electron beam acceleration solution. Summary of the invention

[0008] The present invention provides a magnetic field focusing correction electron beam acceleration system and method to solve the problems mentioned in the above-mentioned prior art.

[0009] In order to achieve the above object, the present invention adopts the following technical solution: a magnetic field focusing and correction electron beam acceleration system, comprising:

[0010] The electron gun uses nanocomposite cathode material for the cathode, and the internal structure of the electron gun is optimized to accurately control the electron beam emission angle and initial divergence.

[0011] The accelerating tube adopts a multi-stage accelerating structure. Each stage of the accelerating structure is composed of a microwave resonant cavity, and its resonant frequency is dynamically adjusted within the range of 5GHz-15GHz. The accelerating tube shell is made of low-loss, high-thermal conductivity ceramic material, and an electron beam collimation device is provided between the accelerating tube and the electron gun;

[0012] The focusing coil is wound by multiple layers of high-temperature superconducting tapes. A cooling channel is provided inside the coil, and liquid helium low-temperature medium is introduced to achieve efficient cooling. The magnetic field distribution of the focusing coil is optimized through the coil winding layout to generate a uniform focusing magnetic field with continuously adjustable magnetic field strength.

[0013] The correction coil adopts a three-dimensional structure design and is composed of multiple independently controlled sub-coils. It generates a correction magnetic field in three dimensions of space. The correction coil and the focusing coil are isolated by a magnetic field coupling device to avoid mutual interference.

[0014] The control system includes a high-precision sensor, a high-speed data acquisition card and an intelligent controller. The sensor uses electron beam diagnostic technology to measure the position, energy, divergence, and beam intensity parameters of the electron beam in real time. The intelligent controller is based on machine learning algorithms and adaptive control strategies. According to the real-time collected data, the dynamic change trend of the electron beam is predicted through a calculation model, and the magnetic field strength of the focusing coil and the correction coil is controlled to achieve focusing and correction of the electron beam.

[0015] Furthermore, the nanocomposite cathode material of the electron gun is synthesized through a preparation process, comprising a tungsten-based material doped with silicon carbide nanoparticles, and the preparation process includes high-temperature sintering and chemical vapor deposition steps. The output voltage stability of the high-voltage power supply of the electron gun is better than ±0.01%.

[0016] Furthermore, the microwave resonant cavity of the accelerating tube adopts an elliptical cavity and a gradual coupling structure design to improve the interaction efficiency between the microwave field and the electron beam. The vacuum system inside the accelerating tube adopts a multi-stage vacuum pump group, and the ultimate vacuum degree can reach 1×10 -8 Pascal below.

[0017] Furthermore, the high-temperature superconducting tape of the focusing coil has high critical current density and low AC loss performance parameters. The coil winding process adopts a non-inductive winding method to improve the uniformity of the magnetic field. The magnetic field adjustment system of the focusing coil adopts a current source adjustment resolution of 0.1 mA.

[0018] Furthermore, the sub-coils of the correction coil are miniaturized in design and made of copper-nickel alloy. Each sub-coil is equipped with an independent driving circuit. The driving circuit uses high-speed switching elements to achieve switching and control of the magnetic field strength. A magnetic field shielding cover is provided around the correction coil to reduce external magnetic field interference.

[0019] Furthermore, the intelligent controller of the control system stores an electron beam behavior model and a correction algorithm library, and automatically selects a suitable control strategy according to different application scenarios and electron beam characteristics. At the same time, the controller is connected to external devices through a high-speed communication interface to achieve remote monitoring and operation, and to record and analyze system operation data in real time.

[0020] Furthermore, a method for applying magnetic field focusing correction to electron beam acceleration comprises the following steps:

[0021] S1. The electron gun emits an electron beam. By controlling the cathode temperature of the electron gun and the voltage parameters of the high-voltage power supply, the electron beam has a predetermined initial energy, emittance and divergence. After passing through the collimator, the electron beam enters the accelerating tube at a high-precision incident angle;

[0022] S2. The accelerating tube dynamically adjusts the resonance frequency of the microwave resonant cavity and the input microwave power according to the energy demand of the electron beam, and accelerates the electron beam efficiently. During the acceleration process, the vacuum degree and microwave field distribution parameters in the accelerating tube are monitored in real time.

[0023] S3, the focusing coil calculates the initial focusing magnetic field strength through the control system according to the initial parameters of the electron beam and the energy change in the acceleration stage, generates a focusing magnetic field to initially focus the electron beam, and continuously monitors the focusing state of the electron beam during the focusing process;

[0024] S4, the sensor monitors the position, energy, and divergence state parameters of the electron beam in real time, and transmits the data to the intelligent controller through the data acquisition card;

[0025] S5. The intelligent controller inputs the received real-time data into the pre-trained electron beam behavior prediction model, and combines it with the algorithm in the correction algorithm library to calculate the strength and direction of the correction magnetic field, control the correction coil to generate the correction magnetic field, and correct the focus of the electron beam. During the correction process, the control parameters are continuously optimized to ensure that the electron beam always maintains the best focusing state during the acceleration process. At the same time, the microwave parameters of the acceleration tube are dynamically adjusted according to the actual state of the electron beam to achieve coordinated optimization of acceleration and focusing.

[0026] S6. Regularly conduct a comprehensive performance evaluation of the system, including the final energy of the electron beam, beam quality, and focusing accuracy indicators. Based on the evaluation results, use machine learning algorithms to automatically optimize and upgrade the models and algorithms in the control system to continuously improve the overall performance of the system. During the operation of the system, use intelligent diagnostic functions to promptly detect potential fault hazards.

[0027] Furthermore, in step S3, the calculation of the initial focusing magnetic field strength is based on a multi-physics field coupling simulation model, taking into account the space charge effect and relativistic effect of the electron beam, and the formula is: Wherein Bf is the focusing magnetic field strength, E0 is the initial energy of the electron beam, D0 is the initial divergence of the electron beam, L is the length of the accelerating tube, I is the electron beam current intensity, ε is the electron beam emittance, m0 is the electron rest mass, c is the speed of light in vacuum, k1 and k2 are coefficients obtained by fitting a large amount of experimental data and simulation results, and in the focusing process, according to the actual focusing situation of the electron beam, an adaptive feedback control algorithm is used to perform real-time fine-tuning on the focusing magnetic field strength, and the fine-tuning formula is: ΔBf=k3×(F-F0)+k4×(D-D0), where ΔBf is the adjustment amount of the focusing magnetic field strength, F is the deviation between the actual focusing position of the electron beam and the ideal focusing position, F0 is the preset focusing position deviation threshold, D is the deviation between the actual divergence of the electron beam and the initial divergence, D0 is the preset divergence deviation threshold, and k3 and k4 are adaptive adjustment coefficients.

[0028] Furthermore, in step S5, the calculation of the correction magnetic field strength and direction adopts a neural network algorithm based on deep learning. The input layer of the neural network is the real-time state parameters of the electron beam, and the output layer is the strength and direction of the correction magnetic field. The training process uses a large amount of simulation and actual experimental data to ensure the accuracy and generalization ability of the algorithm. The correction magnetic field is generated by pulse modulation technology. According to the dynamic changes of the electron beam, the pulse width, frequency and amplitude of the correction magnetic field are controlled to achieve the correction of the electron beam focusing. In the correction process, a fuzzy control strategy is introduced to deal with the uncertainty factors in the system and improve the stability and robustness of the correction.

[0029] Furthermore, in step S6, the performance evaluation index system includes multiple quantitative indicators such as energy stability, beam uniformity, and divergence reduction rate of the electron beam, as well as qualitative indicators such as imaging quality and processing accuracy of the electron beam in practical applications. The system optimization and upgrade process adopts a reinforcement learning algorithm to automatically explore and optimize the parameter settings and algorithm strategies of the control system according to the performance evaluation results. At the same time, a fault prediction model is established to predict the type and time of possible faults in advance based on big data analysis and machine learning technology.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The electron gun of the present invention uses nanocomposite cathode materials and an optimized internal structure, which can accurately control the electron beam emission angle and initial divergence, laying the foundation for subsequent precise acceleration and focusing. For example, in electron beam lithography, nanometer-level processing accuracy can be ensured.

[0032] The focusing coil is wound with multiple layers of high-temperature superconducting tapes, with optimized magnetic field distribution and continuously adjustable intensity. Combined with the three-dimensional structure of the correction coil and independently controlled sub-coils, it can achieve precise focusing and correction of the electron beam in three dimensions of space, so that the electron beam always maintains an ideal state during the acceleration process, effectively improving the beam quality.

[0033] The multi-stage accelerating structure and dynamically adjustable resonant frequency (5GHz-15GHz) of the accelerating tube are combined with an optimized microwave resonant cavity design (elliptical cavity, gradient coupling structure) and a high vacuum system (the ultimate vacuum can reach 1×10 -8 The efficiency of the interaction between the microwave field and the electron beam is greatly improved, achieving efficient acceleration and ensuring the energy stability of the electron beam. For example, in electron microscopes, a stable high-energy electron beam can be provided to improve imaging resolution.

[0034] The high-precision sensors, high-speed data acquisition cards and intelligent controllers in the control system can monitor in real time and accurately control the magnetic field intensity according to the dynamic trend of the electron beam based on machine learning algorithms and adaptive control strategies, achieving coordinated optimization of acceleration and focusing. At the same time, it can automatically select appropriate control strategies according to different application scenarios, and can also remotely monitor operations, which improves the flexibility and ease of use of the system.

[0035] Regular comprehensive performance evaluation and automatic optimization and upgrade mechanism based on machine learning can continuously improve the overall performance of the system and ensure long-term stable operation of the system. For example, in radiation therapy, high-precision electron beam focusing and energy output can be maintained at all times. At the same time, the intelligent diagnosis function can timely detect potential faults, improve system reliability, and reduce maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1A schematic block diagram of a magnetic field focusing and correction electron beam acceleration system proposed by the present invention;

[0037] Figure 2 This is a schematic block diagram of a magnetic field focusing and correction electron beam acceleration method proposed by the present invention. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0040] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, and it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances. The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0041] Reference Figure 1-2 : A magnetic field focusing and correction electron beam acceleration system, comprising:

[0042] The electron gun, whose cathode adopts a new type of high-brightness, long-life nano-composite cathode material, emits an electron beam with a specific energy distribution and low emissivity. The internal structure of the electron gun is optimized and has the function of accurately controlling the electron beam emission angle and initial divergence;

[0043] The accelerating tube adopts a multi-stage accelerating structure. Each stage of the accelerating structure is composed of a unique microwave resonant cavity, and its resonant frequency can be dynamically adjusted within the range of 5GHz-15GHz. The accelerating tube shell adopts a special low-loss, high-thermal conductivity ceramic material, which can effectively dissipate heat and reduce microwave energy loss. An electron beam collimator is provided between the accelerating tube and the electron gun to ensure that the electron beam enters the accelerating tube accurately.

[0044] The focusing coil is wound with multiple layers of high-temperature superconducting tapes. There is a cooling channel inside the coil, which can be fed with liquid helium and other low-temperature media for efficient cooling. The magnetic field distribution of the focusing coil is optimized through a special coil winding layout to produce a highly uniform focusing magnetic field with continuously adjustable magnetic field strength. The magnetic field strength adjustment range can reach 0.1 Tesla to 1 Tesla, and the adjustment accuracy reaches ±0.001 Tesla.

[0045] The correction coil adopts a three-dimensional structure design and is composed of multiple independently controlled sub-coils. It can generate a correction magnetic field in three dimensions of space. The correction magnetic field strength can be precisely adjusted between 10 Gauss and 1000 Gauss, with an adjustment accuracy of ±1 Gauss. The correction coil and the focusing coil are separated by a magnetic field coupling device to avoid mutual interference.

[0046] The control system includes high-precision sensors, high-speed data acquisition cards and intelligent controllers. The sensors use advanced electron beam diagnostic technology and can accurately measure multiple parameters such as the position, energy, divergence, and beam intensity of the electron beam in real time. The data acquisition card collects sensor data at a sampling frequency of more than 1000Hz. The intelligent controller is based on advanced machine learning algorithms and adaptive control strategies. According to the real-time collected data, it predicts the dynamic change trend of the electron beam through complex calculation models, accurately controls the magnetic field strength of the focusing coil and the correction coil, and realizes precise focusing and correction of the electron beam. At the same time, it has fault diagnosis and automatic protection functions, and can take quick measures to protect the safety of the equipment when the system is abnormal.

[0047] In the present invention, the nanocomposite cathode material of the electron gun is synthesized through a specific preparation process, and comprises a tungsten-based material doped with silicon carbide nanoparticles. The preparation process comprises steps such as high-temperature sintering and chemical vapor deposition, so that the cathode has high electron emission efficiency and good stability. The high-voltage power supply of the electron gun adopts a high-precision, low-ripple power supply module, and the output voltage stability is better than ±0.01%.

[0048] In the present invention, the microwave resonant cavity of the accelerating tube adopts innovative designs such as an elliptical cavity and a gradual coupling structure, which can effectively improve the interaction efficiency between the microwave field and the electron beam. The vacuum system inside the accelerating tube adopts a multi-stage vacuum pump group, and the ultimate vacuum degree can reach 1×10 -8Below Pascal, ensuring that the electron beam is not affected by scattering of gas molecules during acceleration.

[0049] In the present invention, the high temperature superconducting tape of the focusing coil has a high critical current density (greater than 10 6 A / cm 2 ), low AC loss (less than 10 -4 W / m) and other special performance parameters. The coil winding process adopts the inductive winding method to further improve the uniformity of the magnetic field. The magnetic field adjustment system of the focusing coil adopts a high-precision current source with a current adjustment resolution of 0.1 mA.

[0050] In the present invention, the sub-coils of the correction coil adopt a miniaturized design and are made of high-strength, high-conductivity copper-nickel alloy material. Each sub-coil is equipped with an independent driving circuit. The driving circuit adopts high-speed switching elements, which can realize rapid switching and precise control of the magnetic field strength. A magnetic field shielding cover is provided around the correction coil to reduce external magnetic field interference.

[0051] In the present invention, a large number of electron beam behavior models and correction algorithm libraries are stored in the intelligent controller of the control system, which can automatically select appropriate control strategies according to different application scenarios and electron beam characteristics. At the same time, the controller is connected to external devices through a high-speed communication interface to achieve remote monitoring and operation, and can record and analyze system operation data in real time, providing a basis for system optimization and troubleshooting.

[0052] In the present invention, a magnetic field focusing correction electron beam acceleration method comprises the following steps:

[0053] S1. The electron gun emits an electron beam. By precisely controlling the electron gun cathode temperature, high voltage power supply voltage and other parameters, the electron beam has a predetermined initial energy (e.g., 50keV-100keV), emittance (less than 0.5mm·mrad) and divergence (less than 0.1°). After passing through the collimator, the electron beam enters the accelerating tube at a high-precision incident angle (less than 0.01°).

[0054] S2. The accelerating tube dynamically adjusts the resonance frequency of the microwave resonant cavity and the input microwave power according to the energy demand of the electron beam to efficiently accelerate the electron beam. During the acceleration process, the vacuum degree, microwave field distribution and other parameters in the accelerating tube are monitored in real time to ensure a stable acceleration environment.

[0055] S3, the focusing coil calculates the initial focusing magnetic field strength through the control system according to the initial parameters of the electron beam and the energy change in the acceleration stage, generates a focusing magnetic field to initially focus the electron beam, and continuously monitors the focusing state of the electron beam during the focusing process;

[0056] S4, the sensor monitors the position, energy, divergence and other state parameters of the electron beam in real time with an ultra-high sampling frequency, and transmits the data to the intelligent controller through the data acquisition card;

[0057] S5. The intelligent controller inputs the received real-time data into the pre-trained electron beam behavior prediction model, and combines it with the algorithm in the correction algorithm library to calculate the strength and direction of the correction magnetic field, control the correction coil to generate the correction magnetic field, and accurately correct the focus of the electron beam. During the correction process, the control parameters are continuously optimized to ensure that the electron beam always maintains the best focusing state during the acceleration process. At the same time, the microwave parameters of the acceleration tube are dynamically adjusted according to the actual state of the electron beam to achieve coordinated optimization of acceleration and focusing.

[0058] S6. Regularly conduct a comprehensive performance evaluation of the system, including indicators such as the final energy of the electron beam (the target energy can reach 1MeV-10MeV), beam quality (such as beam uniformity greater than 95%), and focusing accuracy (focusing error less than 0.05mm). Based on the evaluation results, the machine learning algorithm is used to automatically optimize and upgrade the models and algorithms in the control system to continuously improve the overall performance of the system. During the operation of the system, potential faults are discovered in a timely manner through the intelligent diagnosis function, and maintenance measures are taken in advance to ensure the stable and reliable operation of the system.

[0059] In the present invention, in step S3, the calculation of the initial focusing magnetic field strength is based on a multi-physics field coupling simulation model, taking into account factors such as the space charge effect and the relativistic effect of the electron beam, and the formula is: Where Bf is the focusing magnetic field strength (unit: Tesla), E0 is the initial energy of the electron beam (unit: electron volt), D0 is the initial divergence of the electron beam (unit: radian), L is the length of the accelerating tube (unit: meter), I is the electron beam current intensity (unit: ampere), ε is the electron beam emittance (unit: meter radian), m0 is the electron rest mass (9.10938356×10-31 kg), c is the speed of light in vacuum (299792458 m / s), k1 and k2 are coefficients obtained by fitting a large amount of experimental data and simulation results, and in the focusing process, according to the actual focusing situation of the electron beam, In this paper, an adaptive feedback control algorithm is used to perform real-time fine-tuning on the focusing magnetic field strength according to the dynamic change of the electron beam. The fine-tuning formula is: ΔBf=k3×(F-F0)+k4×(D-D0), where ΔBf is the adjustment amount of the focusing magnetic field strength (unit: Tesla), F is the deviation between the actual focusing position of the electron beam and the ideal focusing position (unit: meter), F0 is the preset focusing position deviation threshold (unit: meter), D is the deviation between the actual divergence of the electron beam and the initial divergence (unit: radian), D0 is the preset divergence deviation threshold (unit: radian), k3 and k4 are adaptive adjustment coefficients, which are updated in real time according to the dynamic change of the electron beam.

[0060] In the present invention, in step S5, the calculation of the correction magnetic field strength and direction adopts a neural network algorithm based on deep learning, the input layer of the neural network is the real-time state parameter of the electron beam, and the output layer is the strength and direction of the correction magnetic field. The training process uses a large amount of simulation and actual experimental data to ensure the accuracy and generalization ability of the algorithm. The correction magnetic field is generated by pulse modulation technology. According to the dynamic changes of the electron beam, the pulse width (in the range of 1μs-100μs), frequency (in the range of 1kHz-100kHz) and amplitude of the correction magnetic field are accurately controlled to achieve fast and accurate correction of the electron beam focusing. In addition, in the correction process, a fuzzy control strategy is introduced to deal with the uncertainty factors in the system and improve the stability and robustness of the correction.

[0061] In the present invention, in step S6, the performance evaluation index system includes multiple quantitative indicators such as energy stability of the electron beam (fluctuation less than ±0.5%), beam uniformity (greater than 95%), divergence reduction rate (greater than 80%), and qualitative indicators such as imaging quality and processing accuracy of the electron beam in practical applications. The system optimization and upgrade process adopts a reinforcement learning algorithm to automatically explore and optimize the parameter settings and algorithm strategies of the control system according to the performance evaluation results. At the same time, a fault prediction model is established to predict the possible fault type and time in advance based on big data analysis and machine learning technology, so as to provide a scientific basis for preventive maintenance and ensure the long-term stable operation of the system.

[0062] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A magnetic field focusing correction electron beam acceleration system, characterized in that: include: The electron gun uses nanocomposite cathode material for the cathode, and the internal structure of the electron gun is optimized to accurately control the electron beam emission angle and initial divergence. The accelerating tube adopts a multi-stage accelerating structure. Each stage of the accelerating structure is composed of a microwave resonant cavity, and its resonant frequency is dynamically adjusted within the range of 5GHz-15GHz. The accelerating tube shell is made of low-loss, high-thermal conductivity ceramic material, and an electron beam collimation device is provided between the accelerating tube and the electron gun; The focusing coil is wound by multiple layers of high-temperature superconducting tapes. A cooling channel is provided inside the coil, and liquid helium low-temperature medium is introduced to achieve efficient cooling. The magnetic field distribution of the focusing coil is optimized through the coil winding layout to generate a uniform focusing magnetic field with continuously adjustable magnetic field strength. The correction coil adopts a three-dimensional structure design and is composed of multiple independently controlled sub-coils. It generates a correction magnetic field in three dimensions of space. The correction coil and the focusing coil are isolated by a magnetic field coupling device to avoid mutual interference. The control system includes a high-precision sensor, a high-speed data acquisition card and an intelligent controller. The sensor uses electron beam diagnostic technology to measure the position, energy, divergence, and beam intensity parameters of the electron beam in real time. The intelligent controller is based on machine learning algorithms and adaptive control strategies. According to the real-time collected data, the dynamic change trend of the electron beam is predicted through a calculation model, and the magnetic field strength of the focusing coil and the correction coil is controlled to achieve focusing and correction of the electron beam.

2. The magnetic field focusing correction electron beam acceleration system according to claim 1, characterized in that: The nanocomposite cathode material of the electron gun is synthesized through a preparation process, comprising a tungsten-based material doped with silicon carbide nanoparticles, the preparation process comprising high-temperature sintering and chemical vapor deposition steps, and the output voltage stability of the high-voltage power supply of the electron gun is better than ±0.01%.

3. The magnetic field focusing correction electron beam acceleration system according to claim 1, characterized in that: The microwave resonant cavity of the accelerating tube adopts an elliptical cavity and a gradual coupling structure design to improve the interaction efficiency between the microwave field and the electron beam. The vacuum system inside the accelerating tube adopts a multi-stage vacuum pump group, and the ultimate vacuum degree can reach 1×10 -8 Pascal or less.

4. The magnetic field focusing correction electron beam acceleration system according to claim 1, characterized in that: The high-temperature superconducting tape of the focusing coil has high critical current density and low AC loss performance parameters. The coil winding process adopts a non-inductive winding method to improve the uniformity of the magnetic field. The magnetic field adjustment system of the focusing coil adopts a current source to adjust the resolution to 0.1 mA.

5. The magnetic field focusing correction electron beam acceleration system according to claim 1, characterized in that: The sub-coils of the correction coil are miniaturized and made of copper-nickel alloy. Each sub-coil is equipped with an independent drive circuit. The drive circuit uses high-speed switching elements to achieve switching and control of magnetic field strength. A magnetic field shielding cover is provided around the correction coil to reduce external magnetic field interference.

6. The magnetic field focusing correction electron beam acceleration system according to claim 1, characterized in that: The intelligent controller of the control system stores the electron beam behavior model and correction algorithm library, and automatically selects the appropriate control strategy according to different application scenarios and electron beam characteristics. At the same time, the controller is connected to external devices through a high-speed communication interface to achieve remote monitoring and operation, and to record and analyze system operation data in real time.

7. A method for accelerating an electron beam by using a magnetic field focusing correction method as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1. The electron gun emits an electron beam. By controlling the cathode temperature of the electron gun and the voltage parameters of the high-voltage power supply, the electron beam has a predetermined initial energy, emittance and divergence. After passing through the collimator, the electron beam enters the accelerating tube at a high-precision incident angle; S2. The accelerating tube dynamically adjusts the resonance frequency of the microwave resonant cavity and the input microwave power according to the energy demand of the electron beam, and accelerates the electron beam efficiently. During the acceleration process, the vacuum degree and microwave field distribution parameters in the accelerating tube are monitored in real time. S3, the focusing coil calculates the initial focusing magnetic field strength through the control system according to the initial parameters of the electron beam and the energy change in the acceleration stage, generates a focusing magnetic field to initially focus the electron beam, and continuously monitors the focusing state of the electron beam during the focusing process; S4, the sensor monitors the position, energy, and divergence state parameters of the electron beam in real time, and transmits the data to the intelligent controller through the data acquisition card; S5. The intelligent controller inputs the received real-time data into the pre-trained electron beam behavior prediction model, and combines it with the algorithm in the correction algorithm library to calculate the strength and direction of the correction magnetic field, control the correction coil to generate the correction magnetic field, and correct the focus of the electron beam. During the correction process, the control parameters are continuously optimized to ensure that the electron beam always maintains the best focusing state during the acceleration process. At the same time, the microwave parameters of the acceleration tube are dynamically adjusted according to the actual state of the electron beam to achieve coordinated optimization of acceleration and focusing. S6. Regularly conduct a comprehensive performance evaluation of the system, including the final energy of the electron beam, beam quality, and focusing accuracy indicators. Based on the evaluation results, use machine learning algorithms to automatically optimize and upgrade the models and algorithms in the control system to continuously improve the overall performance of the system. During the operation of the system, use intelligent diagnostic functions to promptly detect potential fault hazards.

8. The method for accelerating an electron beam by focusing and correcting a magnetic field according to claim 7, characterized in that: In step S3, the calculation of the initial focusing magnetic field strength is based on a multi-physics field coupling simulation model, taking into account the space charge effect and relativistic effect of the electron beam, and the formula is: Wherein Bf is the focusing magnetic field strength, E0 is the initial energy of the electron beam, D0 is the initial divergence of the electron beam, L is the length of the accelerating tube, I is the electron beam current intensity, ε is the electron beam emittance, m0 is the electron rest mass, c is the speed of light in vacuum, k1 and k2 are coefficients obtained by fitting a large amount of experimental data and simulation results, and in the focusing process, according to the actual focusing situation of the electron beam, an adaptive feedback control algorithm is used to perform real-time fine-tuning on the focusing magnetic field strength, and the fine-tuning formula is: ΔBf=k3×(F-F0)+k4×(D-D0), where ΔBf is the adjustment amount of the focusing magnetic field strength, F is the deviation between the actual focusing position of the electron beam and the ideal focusing position, F0 is the preset focusing position deviation threshold, D is the deviation between the actual divergence of the electron beam and the initial divergence, D0 is the preset divergence deviation threshold, and k3 and k4 are adaptive adjustment coefficients.

9. The method for accelerating an electron beam by focusing and correcting a magnetic field according to claim 7, characterized in that: In step S5, the calculation of the correction magnetic field strength and direction adopts a neural network algorithm based on deep learning. The input layer of the neural network is the real-time state parameters of the electron beam, and the output layer is the strength and direction of the correction magnetic field. The training process uses a large amount of simulation and actual experimental data to ensure the accuracy and generalization ability of the algorithm. The correction magnetic field is generated by pulse modulation technology. According to the dynamic changes of the electron beam, the pulse width, frequency and amplitude of the correction magnetic field are controlled to achieve the correction of the electron beam focusing. In the correction process, a fuzzy control strategy is introduced to deal with the uncertainty factors in the system and improve the stability and robustness of the correction.

10. The method for accelerating an electron beam by magnetic field focusing correction according to claim 7, characterized in that: In step S6, the performance evaluation index system includes multiple quantitative indicators such as energy stability, beam uniformity, and divergence reduction rate of the electron beam, as well as qualitative indicators such as imaging quality and processing accuracy of the electron beam in practical applications. The system optimization and upgrade process adopts a reinforcement learning algorithm to automatically explore and optimize the parameter settings and algorithm strategies of the control system according to the performance evaluation results. At the same time, a fault prediction model is established to predict the type and time of possible faults in advance based on big data analysis and machine learning technology.

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