High-flux electron beam quality cooperative control system and method

Abstract

The invention discloses a high-flux electron beam quality cooperative control system and method, belongs to the technical field of electron beam control, and aims to solve the problems that the beam intensity and quality are difficult to consider, the subsystem collaboration is poor and the stability is insufficient. The cooperative control module is in communication connection with the sensing module and is used for receiving the state parameters, analyzing the state parameters based on a preset multi-target optimization algorithm and generating a cooperative control instruction, and the execution module is in communication connection with the cooperative control module and is used for receiving the cooperative control instruction and executing the cooperative control instruction according to the cooperative control instruction. Cooperative control of beam intensity and quality is realized. Through a multi-objective optimization algorithm, the limitation of traditional single parameter control is broken through, the beam intensity is larger than or equal to 100 mA, the emittance is smaller than or equal to 5 pi mm mrad and the energy dispersion is smaller than or equal to 0.5% can be achieved at the same time, and the technical problem that the beam intensity and the emittance are difficult to consider is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electron beam current control, and particularly relates to a high-flux electron beam current quality collaborative control system and method. BACKGROUND

[0002] As a kind of high-energy particle beam, electron beam current has been widely used in industrial irradiation, scientific experiments and other fields. With the upgrading of application requirements, the requirements of "high flux" and "high quality" of the beam current are simultaneously met: high flux means that the beam intensity is large enough (such as ≥100mA) to improve the processing or experimental efficiency; high quality requires that the beam has low emittance (≤5π·mm·mrad) and low energy dispersion (≤0.5%) to ensure the focusing accuracy and uniformity of the beam.

[0003] The existing electron beam current control system has the following technical problems:

[0004] 1. The subsystems such as electron gun, acceleration cavity and focusing system are usually adjusted by independent controllers. For example, when the beam intensity is increased by adjusting the cathode temperature, the emittance may increase; when the emittance is optimized by adjusting the focusing coil current, the beam energy distribution may be affected, and the collaborative optimization of various parameters cannot be realized.

[0005] 2. The traditional control system takes a single parameter (such as beam intensity) as the control target, ignoring the coupling relationship between intensity and quality, which leads to the inability to simultaneously meet the requirements of high flux and high quality.

[0006] 3. The dynamic change of high-flux beam is fast (such as millisecond-level fluctuation), and the perception and decision-making period of the existing control system is relatively long (usually >10ms), which is difficult to compensate for the beam fluctuation in real time, resulting in poor beam stability and affecting the application effect.

[0007] Therefore, a high-flux electron beam current quality collaborative control system and method are needed to solve the problems of the existing technology that the beam intensity and quality are difficult to be considered, the subsystems are poor in collaboration, and the stability is insufficient. SUMMARY

[0008] The purpose of the present application is to provide a high-flux electron beam current quality collaborative control system and method to solve the problems raised in the background art.

[0009] To achieve the above purpose, the present application provides the following technical scheme: a high-flux electron beam current quality collaborative control system, comprising:

[0010] a perception module for real-time acquisition of multi-dimensional state parameters of the electron beam current, the state parameters at least including beam intensity, beam emittance, beam energy dispersion, acceleration cavity electric field strength and focusing coil magnetic field strength;

[0011] The synergic control module is in communication connection with the perception module, configured to receive the state parameters and analyze the state parameters based on a preset multi-objective optimization algorithm to generate a synergic control instruction; the multi-objective optimization algorithm takes "beam intensity ≥ 100 mA (high flux)", "beam emittance ≤ 5π·mm·mrad" and "beam energy dispersion ≤ 0.5% (high quality)" as optimization objectives.

[0012] The execution module is in communication connection with the synergic control module, configured to receive the synergic control instruction and adjust the electron gun cathode temperature, the acceleration cavity power output voltage and the focusing coil driving current according to the synergic control instruction to realize synergic control of the beam intensity and quality.

[0013] It is to be noted that the perception module comprises:

[0014] A beam intensity sensor is configured to collect the instantaneous intensity and average intensity of the electron beam;

[0015] An emittance measuring instrument is configured to measure the beam emittance by a quadrupole scanning method;

[0016] An energy analyzer is configured to collect the energy distribution of the beam and calculate the energy dispersion;

[0017] An electric field sensor is arranged on the inner wall of the acceleration cavity and configured to collect the real-time electric field intensity of the acceleration cavity;

[0018] A magnetic field sensor is arranged outside the focusing coil and configured to collect the real-time magnetic field intensity of the focusing coil.

[0019] It is further to be noted that the synergic control module comprises:

[0020] A data preprocessing unit is configured to filter, denoise and normalize the state parameters collected by the perception module;

[0021] A multi-objective optimization unit is configured to internally build an NSGA-II algorithm or an MOEA / D algorithm, take the beam intensity, emittance and energy dispersion as optimization objectives, take the electron gun cathode temperature, acceleration cavity voltage and focusing coil current as decision variables, and solve the control parameter combination in the Pareto optimal solution set;

[0022] An instruction generation unit is configured to convert the control parameter combination into voltage, current or temperature control instructions recognizable by the execution module.

[0023] It is further to be noted that the execution module comprises:

[0024] Cathode temperature controller: connected with the electron gun cathode, after receiving the cooperative control instruction, the output power of the heating power supply is adjusted to control the cathode temperature, the adjustment range is 800℃-1200℃;

[0025] Accelerating cavity power supply: connected with the accelerating cavity, after receiving the cooperative control instruction, the output voltage is adjusted to change the accelerating cavity electric field intensity, the adjustment range is 1MV-5MV;

[0026] Focusing coil driver: connected with the focusing coil, after receiving the cooperative control instruction, the output current is adjusted to change the coil magnetic field intensity, the adjustment range is 10A-50A.

[0027] The application also provides the following technical scheme: a high-flux electron beam flow quality cooperative control method for realizing the high-flux electron beam flow quality cooperative control system, comprising the following steps:

[0028] Step S1, the multi-dimensional state parameters of the electron beam flow are collected in real time by the sensing module, and the state parameters at least include the beam intensity, the beam emission degree, the beam energy dispersion, the accelerating cavity electric field intensity and the focusing coil magnetic field intensity;

[0029] Step S2, the cooperative control module receives the state parameters, compares them with the preset high-flux threshold (beam intensity≥100mA) and high-quality threshold (emission degree≤5π·mm·mrad, energy dispersion≤0.5%), calculates the adjustment amount of each execution component based on a multi-objective optimization algorithm, and generates a cooperative control instruction;

[0030] Step S3, the execution module synchronously adjusts the electron gun cathode temperature, the accelerating cavity power supply output voltage and the focusing coil driving current according to the cooperative control instruction, so that the beam state parameters meet the high-flux and high-quality thresholds, and the adjustment result is fed back in real time through the sensing module, forming a closed loop control.

[0031] As a preferred embodiment, in the step S1, the collection frequency of the sensing module is not less than 1kHz to meet the real-time control demand of the high-flux beam flow.

[0032] As a preferred embodiment, in the step S2, the constraint conditions of the multi-objective optimization algorithm include: the electron gun cathode temperature is not more than 1200℃, the accelerating cavity voltage fluctuation range is not more than ±0.1%, and the focusing coil current fluctuation range is not more than ±0.5A.

[0033] As a preferred embodiment, the method further comprises a fault diagnosis step, the fault diagnosis step monitors the change rate of each state parameter in real time through the cooperative control module, when the change rate of a certain parameter exceeds the preset threshold, it is determined that the corresponding subsystem is abnormal, a fault warning signal is generated and the execution module is triggered to enter the safe adjustment mode.

[0034] Compared with the prior art, the high-flux electron beam flow quality collaborative control system and method provided by the application has at least the following beneficial effects:

[0035] (1) The application breaks through the limitation of traditional single parameter control through a multi-objective optimization algorithm, and can simultaneously realize beam intensity ≥ 100 mA (high flux), emittance ≤ 5π·mm·mrad, and energy dispersion ≤ 0.5% (high quality), thereby solving the technical problem that the two cannot be considered together.

[0036] (2) The application uses a centralized collaborative control module to replace independent control, realizes synchronous adjustment of the electron gun, the acceleration cavity and the focusing system, and improves the control accuracy to ±0.1% (voltage) and ±0.01A (current), and improves the beam stability (RMS) from 5% in the prior art to within 1%.

[0037] (3) The system communication delay of the application is ≤100μs, and the closed-loop control period is ≤1ms, which can compensate for the dynamic fluctuations of the high-flux beam in real time, and significantly improve the stability and reliability of the beam operation BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 is a structural block diagram of the high-flux electron beam flow quality collaborative control system of the application;

[0039] Figure 2 is a flowchart of the high-flux electron beam flow quality collaborative control method of the application. DETAILED DESCRIPTION

[0040] The application will be further described below in conjunction with examples.

[0041] Please refer to Figure 1 The application provides a high-flux electron beam flow quality collaborative control system, which comprises a perception module, a collaborative control module and an execution module, and the modules communicate with each other through an industrial Ethernet (such as EtherCAT), the communication delay is ≤100μs, and the real-time control requirement is met.

[0042] The perception module: as the “perception end” of the system, it is used for comprehensively collecting beam flow states and subsystem operation parameters. The core components thereof include a beam intensity sensor, an emittance measuring instrument, an energy analyzer, and electric field sensors and magnetic field sensors for monitoring the state of the subsystem; the collection frequency of all the sensors is not less than 1kHz, so as to ensure the dynamic changes of the beam flow.

[0043] Specifically, the beam current sensor selects a brand Faraday cylinder, the measurement range is 0-500 mA, the accuracy is ±0.1 mA, and the sampling frequency is 1 kHz; the emittance measuring instrument adopts a quadrupole scanning type emittance instrument, the measurement range is 0-20π·mm·mrad, the accuracy is ±0.2π·mm·mrad, and the sampling frequency is 1 kHz; the energy analyzer adopts a magnetic deflection type energy analyzer, the energy range is 1 MeV-5 MeV, the resolution is ±0.05%, and the sampling frequency is 1 kHz; the electric field sensor selects a high-voltage electric field sensor, the measurement range is 0-10 MV / m, the accuracy is ±0.1%, and the sampling frequency is 1 kHz; and the magnetic field sensor selects a Hall effect magnetic field sensor, the measurement range is 0-1 T, the accuracy is ±0.05%, and the sampling frequency is 1 kHz.

[0044] The collaborative control module: as the "decision center" of the system, an embedded processor (such as FPGA+ARM architecture) is used to realize high-speed data processing and algorithm operation; the core functions include:

[0045] Data preprocessing: Kalman filter noise reduction is performed on the original data collected by the perception module to eliminate measurement errors caused by electromagnetic interference; at the same time, normalization processing is performed on parameters of different dimensions (such as temperature, voltage, and current) to unify the input of the optimization algorithm.

[0046] Multi-objective optimization: NSGA-II (Non-dominated Sorting Genetic Algorithm II) is built in, and "beam current maximization (≥100 mA)", "emittance minimization (≤5π·mm·mrad)", and "energy dispersion minimization (≤0.5%)" are taken as three optimization objectives, and the electron gun cathode temperature (800℃-1200℃), the accelerating cavity voltage (1MV-5MV), and the focusing coil current (10A-50A) are taken as decision variables, and the Pareto optimal solution set is solved through iterative calculation, and the optimal control parameter combination considering efficiency and quality is selected from the Pareto optimal solution set.

[0047] Instruction generation and fault diagnosis: the optimal control parameters are converted into analog quantities (0-10V) or digital quantities (Modbus protocol) instructions recognizable by the execution module; at the same time, the parameter change rate is monitored in real time, and when the beam current change rate is >5% / ms or the accelerating cavity voltage fluctuation is >±0.1%, a fault warning is triggered immediately and a safety control instruction is generated.

[0048] The execution module: as the "execution end" of the system, it is responsible for converting the collaborative control instructions into hardware actions. The core components include:

[0049] Cathode temperature controller: PID regulation is adopted, the output power (0-10kW) of the heating power supply is changed to control the cathode temperature, the adjustment accuracy is ±1℃, and the response time is <1ms.

[0050] Accelerating cavity power supply: high-voltage DC power supply is adopted, the output voltage is 1MV-5MV, the voltage stability is ±0.05%, the response time is less than 50us, the accelerating cavity electric field intensity is changed by adjusting the power output voltage, and then the beam energy is affected.

[0051] Focusing coil driver: linear current source is adopted, the output current is 10A-50A, the current stability is ±0.01A, the response time is less than 100us, the magnetic field intensity is changed by adjusting the coil current, and the beam focusing and emission degree optimization are realized.

[0052] Specifically, the cathode temperature controller selects a certain brand PID temperature controller, the output power is 0-10kW, the adjustment accuracy is ±1℃, and the response time is less than 1ms; the accelerating cavity power supply selects a certain brand high-voltage DC power supply, the output voltage is 1MV-5MV, the current is 0-200mA, the voltage stability is ±0.05%, and the response time is less than 50us; the focusing coil driver selects a certain brand linear current source, the output current is 10A-50A, the current stability is ±0.01A, and the response time is less than 100us.

[0053] Please refer to Figure 2 The application also provides a high-flux electron beam flow quality collaborative control method for realizing the high-flux electron beam flow quality collaborative control system.

[0054] Step S1, the sensing module collects the beam intensity, the emission degree, the energy dispersion, the accelerating cavity electric field intensity and the focusing coil magnetic field intensity at a frequency of 1kHz, and the collected original data are transmitted in real time to the collaborative control module through the EtherCAT bus.

[0055] Step S2, the collaborative control module filters and normalizes the received data, eliminates noise interference and unifies the dimension.

[0056] The NSGA-II algorithm is called, the processed state parameters are input, the beam intensity is greater than or equal to 100mA, the emission degree is less than or equal to 5pi·mm·mrad, the energy dispersion is less than or equal to 0.5%, the cathode temperature, the accelerating cavity voltage and the focusing coil current are variables, and multi-objective optimization calculation is carried out in combination with constraint conditions (such as cathode temperature ≤1200℃, accelerating cavity voltage fluctuation ≤±0.1%) to generate an optimal control parameter combination.

[0057] The optimal control parameter combination is converted into control instructions (such as cathode temperature 1050℃, accelerating cavity voltage 3MV, focusing coil current 35A) recognizable by the execution module.

[0058] Step S3, after the control instruction is received by the execution module, the cathode temperature controller adjusts the heating power to the corresponding value, the accelerating cavity power adjusts the output voltage to 3MV, and the focusing coil driver adjusts the output current to 35A; at the same time, the sensing module collects the adjusted beam current state parameters in real time, and feeds back to the cooperative control module to form a closed loop control of "sensing-decision-execution-feedback", and the closed loop period is ≤1ms, which ensures that the beam current parameters are stable in the target range.

[0059] Step S4, the cooperative control module monitors the change rate of each parameter in real time, if it is detected that the beam current intensity suddenly decreases by >10% (such as from 120mA to below 100mA), it is determined that the electron gun cathode is abnormal, a fault warning signal is generated immediately, and the execution module is triggered to reduce the cathode temperature by 50℃ and the beam current intensity to 80mA, and after the fault is eliminated, the normal control is restored.

[0060] The application has the following working process: after the system is powered on, the cooperative control module first initializes each subsystem, sets the initial control parameters to cathode temperature 1000℃, accelerating cavity voltage 3MV, and focusing coil current 30A; then, the sensing module collects the key parameters such as beam current intensity (initially about 80mA), emission degree (initially about 8π·mm·mrad) and energy dispersion (initially about 0.8%) in real time at a frequency of 1kHz, and transmits the data to the cooperative control module; the cooperative control module performs multi-objective optimization based on the NSGA-II algorithm, and after 100 iterations, it is identified that the current beam current intensity does not reach the target, and the emission degree and energy dispersion are too high, so a set of optimal control parameters are generated: the cathode temperature is increased to 1050℃ to enhance the beam current intensity, the accelerating cavity voltage is increased to 3.2MV to optimize the energy dispersion, and the focusing coil current is increased to 35A to reduce the emission degree; after the execution module synchronously adjusts the parameters of each component, the sensing module feedbacks the adjustment effect within 1ms: the beam current intensity is increased to 120mA, meeting the high flux requirement; the emission degree is reduced to 4.5π·mm·mrad, and the energy dispersion is reduced to 0.4%, both reaching the high-quality beam standard; the system then enters the closed-loop stable operation stage, and the control parameters are updated every 1ms, so that the beam current intensity is maintained at 115-125mA, the emission degree is stabilized at 4.2-4.8π·mm·mrad, and the energy dispersion is maintained at 0.35-0.45%, continuously meeting the high flux and high quality operation targets; in the fault simulation test, the accelerating cavity voltage is artificially reduced from 3.2MV to 3.1MV (fluctuation 3.1%), the cooperative control module detects that the fluctuation exceeds the ±0.1% threshold, immediately issues a warning, triggers the execution module to adjust the voltage to 3.2MV, and temporarily reduces the beam current intensity to 100mA, and the system recovers to stable operation within 3ms.

[0061] To sum up: the application realizes the collaborative optimization of high flux and high quality by comprehensively collecting beam parameters through the perception module, generating a collaborative control strategy based on a multi-objective optimization algorithm by the collaborative control module, and synchronously adjusting key components by the execution module; specific embodiments show that the system and method can stably output an electron beam with an intensity of 100 mA or more, an emittance of 5pi*mm*mrad or less, and an energy dispersion of 0.5% or less, the beam stability is significantly improved, and the strict requirements of the fields of irradiation processing and particle physics experiments are met.

[0062] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0063] Finally: the above is only a preferred embodiment of the present application and is not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A high flux electron beam current quality synergic control system, characterized in that: The application relates to a method for realizing the coordinated control of beam intensity and quality of an electron beam, and belongs to the field of electron beam technology. The application comprises the following parts: a sensing module: used for collecting multi-dimensional state parameters of an electron beam in real time, wherein the state parameters at least include beam intensity, beam emittance, beam energy dispersion, electric field intensity of an accelerating cavity and magnetic field intensity of a focusing coil; a coordinated control module: in communication connection with the sensing module, used for receiving the state parameters and analyzing the state parameters based on a preset multi-objective optimization algorithm to generate a coordinated control instruction; the multi-objective optimization algorithm takes "beam intensity >= 100 mA (high flux)" "beam emittance <= 5pi*mm*mrad" and "beam energy dispersion <= 0.5% (high quality)" as optimization targets; 2. A high flux electron beam current quality synergic control system according to claim 1, characterized in that: an execution module: in communication connection with the coordinated control module, used for receiving the coordinated control instruction and adjusting the electron gun cathode temperature, the output voltage of the accelerating cavity power supply and the focusing coil driving current according to the coordinated control instruction to realize the coordinated control of beam intensity and quality. The sensing module comprises the following parts: a beam intensity sensor: used for collecting the instantaneous intensity and average intensity of the electron beam; an emittance measuring instrument: used for measuring the beam emittance by a quadrupole scanning method; an energy analyzer: used for collecting the energy distribution of the beam and calculating the energy dispersion; an electric field sensor: arranged on the inner wall of the accelerating cavity and used for collecting the real-time electric field intensity of the accelerating cavity; 3. A high flux electron beam current quality synergic control system according to claim 1, characterized in that: a magnetic field sensor: arranged outside the focusing coil and used for collecting the real-time magnetic field intensity of the focusing coil. The coordinated control module comprises the following parts: a data preprocessing unit: used for filtering, denoising and normalizing the state parameters collected by the sensing module; a multi-objective optimization unit: internally provided with an NSGA-II algorithm or an MOEA / D algorithm, and used for taking the beam intensity, emittance and energy dispersion as optimization targets, taking the electron gun cathode temperature, the accelerating cavity voltage and the focusing coil current as decision variables and solving the control parameter combination in a Pareto optimal solution set; 4. The high flux electron beam current quality synergic control system of claim 1, wherein: an instruction generating unit: used for converting the control parameter combination into voltage, current or temperature control instructions recognizable by the execution module. The execution module comprises the following parts: a cathode temperature controller: connected with the electron gun cathode, used for controlling the cathode temperature by adjusting the output power of a heating power supply after receiving the coordinated control instruction, and the adjustment range is 800 DEG C to 1200 DEG C; an accelerating cavity power supply: connected with the accelerating cavity, used for adjusting the output voltage to change the electric field intensity of the accelerating cavity after receiving the coordinated control instruction, and the adjustment range is 1 MV to 5 MV; 5. A method for high flux electron beam current quality synergic control, for implementing a high flux electron beam current quality synergic control system according to any one of claims 1-4, characterized in that: a focusing coil driver: connected with the focusing coil, used for adjusting the output current to change the magnetic field intensity of the coil after receiving the coordinated control instruction, and the adjustment range is 10 A to 50 A. The method comprises the following steps: Step S1: collecting multi-dimensional state parameters of an electron beam in real time through a sensing module, wherein the state parameters at least include beam intensity, beam emittance, beam energy dispersion, electric field intensity of an accelerating cavity and magnetic field intensity of a focusing coil; Step S2: receiving the state parameters through a coordinated control module, comparing the state parameters with preset high flux threshold values and high quality threshold values, calculating the adjustment amount of each execution component based on a multi-objective optimization algorithm and generating a coordinated control instruction. Step S3, according to the cooperative control instruction, the execution module synchronously adjusts the electron gun cathode temperature, the acceleration cavity power output voltage and the focusing coil driving current, so that the beam state parameters meet the high flux and high quality threshold, and the sensing module feeds back the adjustment result in real time to form a closed loop control.

6. The method of claim 5, wherein: In the step S1, the acquisition frequency of the sensing module is not less than 1 kHz to meet the real-time control requirement of the high flux beam.

7. The method of claim 5, wherein: In the step S2, the constraint conditions of the multi-objective optimization algorithm include that the electron gun cathode temperature is not more than 1200 DEG C, the acceleration cavity voltage fluctuation range is not more than ± 0.1%, and the focusing coil current fluctuation range is not more than ± 0.5A.

8. The method of claim 5, wherein: The method further includes a fault diagnosis step, which monitors the change rate of each state parameter in real time through the cooperative control module, determines that the corresponding subsystem is abnormal when the change rate of a certain parameter exceeds a preset threshold, generates a fault warning signal and triggers the execution module to enter a safe adjustment mode.

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