Beam feedback system and method for accelerator

Abstract

The invention discloses a beam feedback system and method for an accelerator. The beam feedback system comprises an acceleration module beam fast feedback module connected with an acceleration cavity and a harmonic cavity; the acceleration module beam current fast feedback module monitors beam current energy, energy distribution and beam bunch length in the beam current acceleration module to obtain a measurement value of the beam current acceleration module; and controlling the microwave amplitude and phase in the acceleration cavity and / or the harmonic cavity according to the measurement value of the beam acceleration module, so that the beam energy, the energy distribution and the beam bunch length in the beam acceleration module are adjusted to target values. According to the method and the system provided by the invention, the beam fast feedback is synchronously operated in the small loop where each beam acceleration module is located, so that the stable state of the beam in each loop is ensured, and the problem of unstable beam parameters caused by environmental factors such as temperature and humidity fluctuation and external mechanical vibration in the accelerator is solved.

Description

Technical Field

[0001] This invention relates to the field of accelerator technology, and more particularly to a beam feedback system and method for accelerators. Background Technology

[0002] To achieve high-quality laser output, beam control of the particle stream in the accelerator is necessary to ensure its optimal performance. This performance includes several aspects such as the stability of beam energy, bundle length, and arrival time.

[0003] Due to factors such as changes in humidity and temperature in the environment and external mechanical vibrations, parameters such as beam intensity and position will drift slowly during accelerator operation, resulting in weakened light output performance and inability to output a particle beam that meets the required precision.

[0004] Therefore, the existing technology needs further improvement. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide users with a beam feedback system and implementation method for accelerators, overcoming the problem of unstable beam parameters in accelerators caused by environmental factors or external mechanical vibrations in the prior art.

[0006] The technical solution adopted by this invention to solve the technical problem is as follows: In a first aspect, the present invention discloses a beam feedback system for an accelerator, wherein the accelerator includes: a plurality of beam acceleration modules, the beam acceleration modules including: acceleration cavities and harmonic cavities connected in sequence; the beam feedback system includes: a fast beam feedback module of the acceleration module connected to both the acceleration cavities and harmonic cavities. The acceleration module beam fast feedback module includes: an acceleration module detection element and an acceleration module adjustment element; The acceleration module detection element is used to monitor the beam energy, energy distribution and bundle length in the beam acceleration module to obtain the measured values ​​of the beam acceleration module; The acceleration module adjustment element is used to control the microwave amplitude and phase in the acceleration cavity and / or harmonic cavity according to the measured values ​​of the beam acceleration module, so as to adjust the beam energy, energy distribution and bundle length in the beam acceleration module to the target values.

[0007] Optionally, the acceleration module adjustment element includes: an amplitude adjustment subunit and a phase adjustment subunit; The amplitude adjustment subunit is used to adjust the beam energy according to the amplitude of the microwave; The phase adjustment subunit is used to adjust the energy distribution and bundle length of the beam according to the phase of the microwave.

[0008] Optionally, the accelerator further includes an electron gun; the beam feedback system further includes an electron gun beam fast feedback module connected to the electron gun; the electron gun beam fast feedback module includes a bundle parameter detection element and a bundle parameter adjustment element; The cluster parameter detection element is connected to the rear end of the electron gun and is used to detect the cluster charge and cluster arrival time of the electron beam emitted by the electron gun. The bundle parameter adjustment element is connected to both the electron gun and the bundle parameter detection element. It is used to adjust the laser power input to the electron gun according to the bundle charge detected by the bundle parameter detection element, and to adjust the laser delay time according to the detected bundle arrival time, so as to adjust the bundle charge and arrival time of the electron beam to the target values.

[0009] Optionally, the accelerator further includes at least one accelerating heating module, the accelerating heating module including: at least one accelerating cavity and a laser heater connected to the accelerating cavity; the beam feedback system further includes: a laser heater beam fast feedback module connected to both the accelerating cavity and the laser heater; the laser heater beam fast feedback module includes: a beam energy detection element and a microwave control element; The beam energy detection element is used to monitor the beam energy in the laser heater and obtain a measured value of the beam energy. The microwave control element is connected to the accelerating cavity and the beam energy detection element, and is used to control the microwave amplitude of the accelerating cavity according to the measured value of the beam energy, so that the measured value of the beam energy reaches the target value.

[0010] Optionally, the relationship between the microwave amplitude and the beam energy is as follows: ΔE=q×E0×L×cos(φ s )×T; Where: ΔE is the energy gain gained by the particle, q is the charge of the particle, E0 is the microwave amplitude of the accelerating cavity, and L is the effective acceleration length of the accelerating cavity; φ s The phase of the particle relative to the microwave when it enters the accelerating cavity is denoted as T, and the transit time factor is denoted as T.

[0011] Optionally, the electron gun beam fast feedback module, the laser heater beam fast feedback module, and the acceleration module beam fast feedback module all include: multiple SFP interfaces, an FPGA connected to each SFP interface, a phase-locked loop connected to the FPGA, a memory, a module management controller, and a power manager.

[0012] Optionally, the beam feedback system and the accelerator use optical fibers for data transmission.

[0013] Secondly, the present invention also discloses a beam feedback method for an accelerator, wherein, utilizing the aforementioned beam feedback system, the beam feedback method includes: The beam energy, energy distribution, and bundle length in the beam acceleration module are monitored to obtain the measured values ​​of the beam acceleration module; The microwave amplitude and phase in the acceleration cavity and / or harmonic cavity are controlled based on the measured values ​​of the beam acceleration module, so that the beam energy, energy distribution and bundle length in the beam acceleration module are adjusted to the target values.

[0014] Optionally, the method further includes: The charge amount and arrival time of the electron beam emitted by the detector electron gun are measured. The laser power of the input electron gun is adjusted according to the detected amount of charge in the cluster, and the laser delay time is adjusted according to the detected arrival time of the cluster, so as to adjust the amount of charge in the cluster and the arrival time of the electron beam to the target value. Furthermore, the beam energy in the laser heater is monitored to obtain a measured value of the beam energy, and the microwave amplitude of the accelerating cavity is controlled based on the measured value of the beam energy so that the measured value of the beam energy reaches the target value.

[0015] Optionally, before the step of monitoring the beam energy, energy distribution, and bundle length in the beam acceleration module to obtain the measured values ​​of the beam acceleration module, the method further includes: The initial laser power, initial laser delay time, initial microwave amplitude and initial phase of the accelerating cavity, and initial microwave amplitude and initial phase of the harmonic cavity are determined by physical simulation. The initial laser power, initial laser delay time, initial microwave amplitude and initial phase of the accelerating cavity, and initial microwave amplitude and initial phase of the harmonic cavity are used as the initial equipment control parameters when the beam feedback control of the accelerator is started.

[0016] Beneficial effects: This invention discloses a beam feedback system and method for an accelerator. The beam feedback system includes: a fast beam feedback module connected to both the accelerating cavity and the harmonic cavity; the fast beam feedback module monitors the beam energy, energy distribution, and bundle length in the beam accelerating module to obtain measured values; and controls the microwave amplitude and phase in the accelerating cavity and / or harmonic cavity based on the measured values ​​to adjust the beam energy, energy distribution, and bundle length in the beam accelerating module to target values. The method and system provided by this invention solve the problem of unstable beam parameters caused by environmental factors such as temperature and humidity fluctuations and external mechanical vibrations in accelerators by synchronously operating fast beam feedback in small loops in each beam accelerating module. Attached Figure Description

[0017] Figure 1 This is a structural principle block diagram of the beam feedback system for accelerators disclosed in this invention; Figure 2 This is a distribution diagram of the beam feedback system at various locations on the accelerator in an embodiment of the present invention; Figure 3 This is a flowchart of the beam feedback method for accelerators disclosed in this invention. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] In free-electron laser devices based on superconducting linear accelerators, the beam emitted from the electron gun needs to be accelerated multiple times within the accelerator using an accelerating cavity to reach the target high-energy state. To achieve a high-quality output beam, it is necessary to ensure good beam performance within the accelerator, including beam energy, bundle length, and stability of arrival time. In practical applications, due to environmental factors such as temperature and humidity variations and external mechanical vibrations, beam intensity, position, and other parameters can drift during accelerator operation, affecting subsequent light output. Therefore, beam control is required during acceleration to meet the performance requirements.

[0020] To control the beam during acceleration, feedback adjustments to beam parameters at multiple locations are required to ensure the correct and stable beam state at each location. Existing technologies typically integrate these feedback adjustments into a single loop, adjusting the beam parameters at each location based on the feedback of this entire loop. While this approach can comprehensively control each location, the algorithm design is complex, and a problem at one location can affect the entire loop. Therefore, it suffers from limitations in the number of measurement parameters, low measurement accuracy, and limited control accuracy, failing to meet the requirements for simple design, reliable performance, and high-precision control.

[0021] To provide a simple feedback control method that meets the requirements of high-precision beam control, this invention provides a beam feedback system and method for accelerators. Utilizing a fast beam feedback module connected to each beam acceleration module, the beam energy, energy distribution, and bundle length in each beam acceleration module are monitored to obtain measured values. Based on these measured values, the microwave amplitude and phase within the acceleration cavity and harmonic cavity are controlled to adjust the beam energy, energy distribution, and bundle length in the beam acceleration module to target values. The method and system provided by this invention achieve precise control of the beam in each loop through synchronous feedback control of multiple small loops, offering advantages such as simple design, convenient implementation, and stable control performance.

[0022] The following description, in conjunction with the accompanying drawings, provides a more detailed account of a beam feedback system and method for an accelerator according to this embodiment.

[0023] In a first aspect, the present invention discloses a beam feedback system for an accelerator, such as Figure 1 As shown, this is applied to an accelerator. The accelerator 10 includes: multiple beam acceleration modules 110, each beam acceleration module 110 including: acceleration cavities and harmonic cavities connected in sequence; the beam feedback system 20 includes: a fast beam feedback module 210 for the acceleration modules connected to both the acceleration cavities and harmonic cavities. The fast beam feedback module 210 for the acceleration modules includes: an acceleration module detection element 2111 and an acceleration module adjustment element 2112.

[0024] The acceleration module detection element 2111 is used to monitor the beam energy, energy distribution, and bundle length in the beam acceleration module to obtain the measured values ​​of the beam acceleration module. The acceleration module adjustment element 2112 is used to control the microwave amplitude and phase in the acceleration cavity and / or harmonic cavity according to the measured values ​​of the beam acceleration module, so as to adjust the beam energy, energy distribution, and bundle length in the beam acceleration module to the target values.

[0025] Combination Figure 2The diagram shows the structural layout of the beam acceleration modules and fast feedback modules on various beam acceleration modules of an accelerator. An accelerator is a device that increases the velocity of charged particles, aiming to accelerate particles to high energies. The beam acceleration module includes at least one accelerating cavity and a harmonic cavity. The accelerating cavities, located on the accelerator, are used to boost the energy of charged particles through a high-frequency electric field. This is mainly achieved through accelerating voltage and electric field uniformity to ensure that ions obtain a stable and efficient energy gain when passing through the accelerating cavity. The harmonic cavity is used to improve the properties of the electron beam, including beam modulation and noise suppression.

[0026] In addition to the acceleration cavity and harmonic cavity, the beam acceleration module also includes a bunch compressor connected downstream of the harmonic cavity. The bunch compressor, typically including focusing and dispersive elements, is used to compress the length of the charged particle bunches to increase the peak flux and maintain beam quality. The beam emitted from the electron gun undergoes multiple acceleration, energy gain, and compression processes to obtain a high-energy beam.

[0027] To monitor the beam parameters in each beam acceleration module, in one embodiment, a fast beam feedback module is provided between each bundle compressor and the acceleration cavity and harmonic cavity. This fast beam feedback module is used to acquire the beam parameters in each bundle compressor, so as to adjust the beam passing through the bundle compressor based on the measured values ​​of the acquired beam parameters in the beam acceleration module, thereby improving the stability and optical characteristics of the output beam.

[0028] In detail, the fast feedback module for the acceleration module includes an acceleration module detection element and an acceleration module adjustment element. In a specific implementation, the acceleration module detection element monitors the bundle parameters within the bundle compressor to obtain the beam energy, energy distribution, and bundle length. In one implementation, the acceleration module detection element can be a beam energy detector, a beam energy distribution detector, and a bundle length detector to detect the beam energy, energy distribution, and bundle length, respectively, and obtain the corresponding measurement values.

[0029] Furthermore, beam energy can be detected by a beam position detector located in the dispersive region. Based on the dispersion function known from the detector's installation location, the energy of each bundle can be measured. A bundle energy dispersion detector (SRM - Synchrotron Radiation Monitor) is used to detect bundle energy dispersion by measuring the synchrotron radiation emitted by the bundle as it passes through the diode of the bundle compressor. A bundle length detector (BCM - Bunch Compression Monitor) is used to measure the length of each bundle; it is typically installed after the bundle compressor.

[0030] Based on a sinusoidal accelerating electric field, when the beam head is at peak acceleration and the tail is in a phase-lagging position, the head receives more energy and accelerates faster, while the tail receives less energy and accelerates slower. This increases the distance between the head and tail, leading to a more dispersed energy distribution and a longer bundle length. Conversely, if the beam tail is at peak acceleration and the head is in a phase-leading position, the distance between the head and tail is shorter, the energy distribution becomes more concentrated, and the bundle length is shorter. Therefore, beam energy, energy distribution, and bundle length can be controlled by adjusting the microwave amplitude and phase. When the beam energy distribution detector or bundle length detector detects a deviation between the beam parameters and the target value, the output microwave phase is adjusted accordingly, thereby changing the beam intensity to meet the requirements.

[0031] Therefore, once the acceleration module's detection element obtains measurements of the beam energy, energy distribution, and bundle length, the beam energy, energy distribution, and bundle length can be controlled by adjusting the microwave amplitude and phase within the acceleration cavity and harmonic cavity, since these parameters are directly related to the beam energy, energy distribution, and bundle length. Combined with... Figure 2 As shown, the fast feedback module of the acceleration module adjusts the acceleration cavity (such as...) based on the measured values. Figure 2 Large modules CM02 and CM03) and harmonic cavities (such as Figure 2 The microwave amplitude and phase of CMH01 and CMH02 in the beam acceleration module are controlled to adjust the energy distribution and bundle length of the beam in the beam acceleration module.

[0032] In the beam feedback system provided in this embodiment, an acceleration module beam fast feedback module is connected to the back end of each bundle compressor. The acceleration module beam fast feedback module monitors the beam energy, energy distribution, and bundle length in the bundle compressor. Based on the measured values ​​of beam energy, energy distribution, and bundle length in the bundle compressor, the microwave amplitude and phase in the acceleration cavity and / or harmonic cavity are adjusted to ensure that the measured values ​​of beam energy, energy distribution, and bundle length in each beam acceleration module are consistent with the target values, thereby improving the stability of beam parameters in each beam acceleration module.

[0033] Furthermore, the acceleration module adjustment element includes: an amplitude adjustment subunit and a phase adjustment subunit.

[0034] The amplitude adjustment subunit is used to adjust the beam energy according to the amplitude of the microwave.

[0035] The phase adjustment subunit is used to adjust the energy distribution and bundle length of the beam according to the phase of the microwave.

[0036] In other words, the amplitude adjustment subunit is used to regulate the beam energy, and the phase adjustment subunit is used to control the energy distribution and beam length. The microwave amplitude within the accelerating cavity is the electric field intensity. This electric field component of the electromagnetic field within the accelerating cavity changes periodically. When the beam passes through the accelerating cavity, a larger microwave amplitude results in a larger increase in beam energy, while a smaller amplitude results in a smaller increase in beam energy. Therefore, by controlling the microwave amplitude, the increase in beam energy can be adjusted. Similarly, the harmonic cavity controls the electric field intensity to change the energy gain of particles within the cavity, thereby precisely regulating the beam energy.

[0037] Enter a place, combine Figure 2 As shown, the accelerator also includes an electron gun; the beam feedback system further includes an electron gun beam fast feedback module connected to the electron gun; the electron gun beam fast feedback module includes a bundle parameter detection element and a bundle parameter adjustment element.

[0038] The cluster parameter detection element is connected to the rear end of the electron gun and is used to detect the cluster charge and cluster arrival time of the electron beam emitted by the electron gun.

[0039] The bundle parameter adjustment element is connected to both the electron gun and the bundle parameter detection element. It is used to adjust the laser power input to the electron gun according to the bundle charge detected by the bundle parameter detection element, and to adjust the laser delay time according to the detected bundle arrival time, so as to adjust the bundle charge and arrival time of the electron beam to the target values.

[0040] In this embodiment, an electron gun beam fast feedback module is set at the rear end of the electron gun to monitor the charge and arrival time of the electron gun beam cluster, and to control the power and delay of the input laser based on the measured values.

[0041] Within the operating range, a higher input laser power results in a greater number of excited photoelectrons, leading to a larger charge in the cluster. The laser delay controls the timing of electron generation in the electron gun, thus controlling the cluster arrival time. When the cluster charge detector or cluster arrival time detector detects a deviation between the cluster parameters and the target value, the output laser power and delay are adjusted accordingly, thereby changing the beam parameters to meet the requirements.

[0042] In one implementation, a charge detector, Turbo ICT (Integrating Current Transformer), is used to measure the charge of each bundle. This detector can be installed at the electron gun exit and other locations where precise charge measurement is required. A Bunch Arrival Time Monitor (BAM) is used to measure the arrival time of each bundle. This monitor can be installed at the electron gun exit.

[0043] Furthermore, combined Figure 2 As shown, the accelerator further includes at least one accelerating heating module, which includes: at least one accelerating cavity and a laser heater connected to the accelerating cavity; the beam feedback system further includes: a laser heater beam fast feedback module connected to both the accelerating cavity and the laser heater; the laser heater beam fast feedback module includes: a beam energy detection element and a microwave control element.

[0044] The beam energy detection element is used to monitor the beam energy in the laser heater and obtain a measured value of the beam energy; the microwave control element is connected to the acceleration cavity and the beam energy detection element and is used to control the microwave amplitude of the acceleration cavity according to the measured value of the beam energy so that the measured value of the beam energy reaches the target value.

[0045] Specifically, the relationship between the microwave amplitude and the beam energy is as follows: ΔE=q×E0×L×cos(φ s )×T; Where: ΔE is the energy gain gained by the particle, q is the charge of the particle, E0 is the microwave amplitude of the accelerating cavity, and L is the effective acceleration length of the accelerating cavity; φ s The phase of the particle relative to the microwave when it enters the accelerating cavity is denoted as T, and the transit time factor is denoted as T.

[0046] In this embodiment, the beam energy in the laser heater is monitored, and the fast beam feedback module of the laser heater is used to monitor the acceleration cavity (e.g., Figure 2 The microwave amplitude of the accelerator small module CM00 and the accelerator large module CM01 shown is controlled to accelerate the beam. Since the microwave amplitude directly and linearly affects the beam energy, the higher the microwave amplitude in the accelerating cavity, the greater the beam energy measured in the laser heater.

[0047] Furthermore, in order to achieve rapid feedback of beam parameters, the electron gun beam fast feedback module, the laser heater beam fast feedback module, and the bundle compressor beam fast feedback module all include: multiple SFP interfaces, an FPGA connected to each SFP interface, a phase-locked loop connected to the FPGA, a memory, a module management controller, and a power manager.

[0048] Because the electron gun beam feedback module, laser heater beam feedback module, and acceleration module beam feedback module all contain multiple SFP interfaces and FPGA components, they can receive and process multiple high-speed signals quickly, and then use corresponding algorithms to control the respective modules rapidly and effectively. A phase-locked loop (PLL) provides a stable and clean clock signal to the FPGA, enabling it to process high-speed signals efficiently. The module management controller (MMC), a microcontroller embedded on the board, is responsible for monitoring, managing, and protecting the module. Dynamic random access memory (SDRAM) is a core memory chip in high-performance computing platforms, temporarily storing data or instructions being processed by the FPGA. The power management module monitors, controls, and optimizes power distribution and consumption to improve energy efficiency, extend battery life, and ensure stable system operation. In practical use, the electron gun beam feedback module, laser heater beam feedback module, and bundle compressor beam feedback module are connected to a host computer in the form of beam feedback boards for unified management.

[0049] To achieve more accurate beam control, the beam feedback system and accelerator in this embodiment use optical fiber for data transmission. In specific implementation, optical fiber is used as the main channel for uploading all monitoring data to the host computer for feedback processing, so as to realize the rapid transmission of monitoring data to each beam fast feedback.

[0050] The beam feedback system disclosed in this embodiment not only solves the problem of beam parameter instability caused by environmental factors such as temperature and humidity fluctuations and external mechanical vibrations in accelerators, but also overcomes the limitations of traditional feedback systems, such as insufficient data bandwidth and slow processing speed, which prevent rapid, multi-point real-time measurement and control of beam parameters. It improves the long-term stability and accuracy of the overall beam performance (such as charge, energy, bundle length, and arrival time) in large accelerators, meeting the stringent requirements of high-precision experiments and operations.

[0051] Secondly, based on the disclosed beam feedback system, this invention also discloses a beam feedback method for accelerators, such as... Figure 3 As shown, the beam feedback method includes: Step S1: Monitor the beam energy, energy distribution, and bundle length in the beam acceleration module to obtain the measured values ​​of the beam acceleration module.

[0052] Step S2: Control the microwave amplitude and phase in the acceleration cavity and / or harmonic cavity according to the measured values ​​of the beam acceleration module, so that the beam energy, energy distribution and bundle length in the beam acceleration module are adjusted to the target values.

[0053] Furthermore, the method also includes: The charge amount and arrival time of the electron beam emitted by the detector electron gun are measured. The laser power of the input electron gun is adjusted according to the detected amount of charge in the cluster, and the laser delay time is adjusted according to the detected arrival time of the cluster, so as to adjust the amount of charge in the cluster and the arrival time of the electron beam to the target value. Furthermore, the beam energy in the laser heater is monitored to obtain a measured value of the beam energy, and the microwave amplitude of the accelerating cavity is controlled based on the measured value of the beam energy so that the measured value of the beam energy reaches the target value.

[0054] Furthermore, before the step of monitoring the beam energy, energy distribution, and bundle length in the beam acceleration module to obtain the measured values ​​of the beam acceleration module, the method further includes: The initial laser power, initial laser delay time, initial microwave amplitude and initial phase of the accelerating cavity, and initial microwave amplitude and initial phase of the harmonic cavity are determined by physical simulation. The initial laser power, initial laser delay time, initial microwave amplitude and initial phase of the accelerating cavity, and initial microwave amplitude and initial phase of the harmonic cavity are used as the initial equipment control parameters when the beam feedback control of the accelerator is started.

[0055] In detail, since beam feedback control in accelerators is an extremely complex process, the specific feedback control method needs to be obtained through physical simulation (including numerical calculations and software simulations) in the early stages of design, serving as a guide for the initial design phase. After construction is completed, multiple open-loop and closed-loop tests are required to determine the actual impact of the aforementioned control parameters on the beam, and to consider the coupling between different loops, thereby obtaining a specific feedback control algorithm. Depending on the specific beam parameters to be obtained, the specific algorithm may also require targeted adjustments.

[0056] The system and method disclosed in this invention employ distributed sensing and monitoring techniques. By deploying beam diagnostic equipment at key nodes of the accelerator, multi-dimensional beam parameters are acquired in real time. Through multi-point, real-time feedback, various slowly and rapidly changing disturbances in the beam generated within the accelerator are effectively suppressed, keeping beam parameters near ideal setpoints over a long period and improving beam stability. Furthermore, multiple feedback mechanisms provide high-precision control over different modules, thereby altering some beam parameters and achieving closed-loop beam control.

[0057] The beam feedback system and method provided by this invention further leverage the high bandwidth of optical fiber and the parallel hardware processing capabilities of FPGA, resulting in an extremely short closed-loop response time (down to the microsecond level). This allows for timely correction of beam deviations and rapid response and control of parameter adjustments. Consequently, it improves the output optical characteristics of the free-electron laser (such as brightness and stability), reduces experimental interruptions caused by beam instability, and enhances system operating efficiency. Furthermore, the proposed modular chassis design and centralized intelligent power management facilitate system monitoring, diagnosis, and maintenance, enhancing system maintainability and reliability.

[0058] This invention discloses a beam feedback system and method for an accelerator. The beam feedback system includes: a fast beam feedback module connected to both the accelerating cavity and the harmonic cavity; the fast beam feedback module monitors the beam energy, energy distribution, and bundle length in the beam acceleration module to obtain measured values; and controls the microwave amplitude and phase in the accelerating cavity and / or harmonic cavity based on the measured values ​​to adjust the beam energy, energy distribution, and bundle length to target values. The method and system provided by this invention solve the problem of unstable beam parameters caused by environmental factors such as temperature and humidity fluctuations and external mechanical vibrations in accelerators by synchronously operating fast beam feedback in the small loops of each beam acceleration module.

[0059] Other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of the invention are indicated by the following claims.

[0060] The embodiments described above are merely examples of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application.

Claims

1. A beam feedback system for an accelerator, characterized in that, The invention is applied to an accelerator, which includes: multiple beam acceleration modules, each beam acceleration module including: acceleration cavities and harmonic cavities connected in sequence; the beam feedback system includes: a fast beam feedback module of the acceleration module connected to both the acceleration cavities and harmonic cavities. The acceleration module beam fast feedback module includes: an acceleration module detection element and an acceleration module adjustment element; The acceleration module detection element is used to monitor the beam energy, energy distribution and bundle length in the beam acceleration module to obtain the measured values ​​of the beam acceleration module; The acceleration module adjustment element is used to control the microwave amplitude and phase in the acceleration cavity and / or harmonic cavity according to the measured values ​​of the beam acceleration module, so as to adjust the beam energy, energy distribution and bundle length in the beam acceleration module to the target values.

2. The beam feedback system for an accelerator according to claim 1, characterized in that, The acceleration module adjustment element includes: an amplitude adjustment subunit and a phase adjustment subunit; The amplitude adjustment subunit is used to adjust the beam energy according to the amplitude of the microwave; The phase adjustment subunit is used to adjust the energy distribution and bundle length of the beam according to the phase of the microwave.

3. The beam feedback system for an accelerator according to claim 1, characterized in that, The accelerator also includes an electron gun; the beam feedback system further includes an electron gun beam fast feedback module connected to the electron gun; the electron gun beam fast feedback module includes a bundle parameter detection element and a bundle parameter adjustment element; The cluster parameter detection element is connected to the rear end of the electron gun and is used to detect the cluster charge and cluster arrival time of the electron beam emitted by the electron gun. The bundle parameter adjustment element is connected to both the electron gun and the bundle parameter detection element. It is used to adjust the laser power input to the electron gun according to the bundle charge detected by the bundle parameter detection element, and to adjust the laser delay time according to the detected bundle arrival time, so as to adjust the bundle charge and arrival time of the electron beam to the target values.

4. The beam feedback system for an accelerator according to claim 1, characterized in that, The accelerator further includes at least one accelerating heating module, which includes: at least one accelerating cavity and a laser heater connected to the accelerating cavity; the beam feedback system further includes: a laser heater beam fast feedback module connected to both the accelerating cavity and the laser heater; the laser heater beam fast feedback module includes: a beam energy detection element and a microwave control element; The beam energy detection element is used to monitor the beam energy in the laser heater and obtain a measured value of the beam energy. The microwave control element is connected to the accelerating cavity and the beam energy detection element, and is used to control the microwave amplitude of the accelerating cavity according to the measured value of the beam energy, so that the measured value of the beam energy reaches the target value.

5. The beam feedback system for an accelerator according to claim 4, characterized in that, The relationship between the microwave amplitude and the beam energy is as follows: ΔE=q×E0×L×cos(φ s )×T; Where: ΔE is the energy gain gained by the particle, q is the charge of the particle, E0 is the microwave amplitude of the accelerating cavity, and L is the effective acceleration length of the accelerating cavity; φ s The phase of the particle relative to the microwave when it enters the accelerating cavity is denoted as T, and the transit time factor is denoted as T.

6. The beam feedback system for an accelerator according to claim 4, characterized in that, The electron gun beam fast feedback module, the laser heater beam fast feedback module, and the acceleration module beam fast feedback module all include: multiple SFP interfaces, an FPGA connected to each SFP interface, a phase-locked loop connected to the FPGA, a memory, a module management controller, and a power manager.

7. The beam feedback system for an accelerator according to any one of claims 1-6, characterized in that, The beam feedback system and accelerator use optical fibers for data transmission.

8. A beam feedback method for accelerators, characterized in that, Utilizing the beam feedback system as described in claim 1, the beam feedback method includes: The beam energy, energy distribution, and bundle length in the beam acceleration module are monitored to obtain the measured values ​​of the beam acceleration module; The microwave amplitude and phase in the acceleration cavity and / or harmonic cavity are controlled based on the measured values ​​of the beam acceleration module, so that the beam energy, energy distribution and bundle length in the beam acceleration module are adjusted to the target values.

9. The beam feedback method for an accelerator according to claim 8, characterized in that, The beam feedback method further includes: The charge amount and arrival time of the electron beam emitted by the detector electron gun are measured. The laser power of the input electron gun is adjusted according to the detected amount of charge in the cluster, and the laser delay time is adjusted according to the detected arrival time of the cluster, so as to adjust the amount of charge in the cluster and the arrival time of the electron beam to the target value. Furthermore, the beam energy in the laser heater is monitored to obtain a measured value of the beam energy, and the microwave amplitude of the accelerating cavity is controlled based on the measured value of the beam energy so that the measured value of the beam energy reaches the target value.

10. The beam feedback method for an accelerator according to claim 8, characterized in that, Before the step of monitoring the beam energy, energy distribution, and bundle length in the beam acceleration module to obtain the measured values ​​of the beam acceleration module, the method further includes: The initial laser power, initial laser delay time, initial microwave amplitude and initial phase of the accelerating cavity, and initial microwave amplitude and initial phase of the harmonic cavity are determined by physical simulation. The initial laser power, initial laser delay time, initial microwave amplitude and initial phase of the accelerating cavity, and initial microwave amplitude and initial phase of the harmonic cavity are used as the initial equipment control parameters when the beam feedback control of the accelerator is started.

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