Negative feedback automatic energy regulation and control device and method suitable for low-energy linear accelerator

Abstract

The invention relates to a negative feedback automatic energy regulation and control device and method suitable for a low-energy linear accelerator. The device comprises a first beam consulting room and a second beam consulting room, the first beam consulting room comprises a first Faraday cup, the second beam consulting room comprises a second Faraday cup, a mass spectrum dipolar magnet is arranged between the first beam consulting room and the second beam consulting room, a beam enters the mass spectrum dipolar magnet after passing through the first beam consulting room, the direction of the beam is changed in the mass spectrum dipolar magnet, and the beam enters the second beam consulting room after passing through the second Faraday cup. The beam enters a second beam consulting room after passing through a mass spectrum dipolar magnet, first beam intensity is obtained by measuring a first Faraday cup in the first beam consulting room, second beam intensity is obtained by monitoring a second Faraday cup in the second beam consulting room, amplitude and phase parameters of a high-frequency cavity are dynamically adjusted through a negative feedback control algorithm, and the beam intensity is obtained. And stopping until the second beam intensity is smaller than a first set proportion of the first beam intensity. The beam energy divergence can be automatically regulated and controlled, beam energy divergence information is automatically detected and is fed back to the control system in real time for energy divergence stabilization.

Description

Technical Field

[0001] The present invention relates to the field of accelerator technology, in particular to a device and method for automatically controlling beam energy in a low-energy linear accelerator, and more particularly to a negative feedback control technology based on multi-system collaboration for optimizing beam energy dispersion, energy deviation and transmission efficiency. Background Art

[0002] In recent years, low-energy, high-current heavy-ion linear accelerators have played an important role in nuclear physics, nuclear materials research, and high-energy physics experiments. Ion beam energy control technology is particularly crucial in nuclear astrophysics and irradiation experiments.

[0003] Existing beam energy control devices mainly rely on manual adjustment, which switches and optimizes the beam energy by manually adjusting the accelerator's high-frequency cavity parameters and the operating point of the beam magnet. However, manual control has the following significant drawbacks:

[0004] 1. Time-consuming and labor-intensive: In multi-point energy control experiments, researchers need to frequently adjust beamline components, such as high-frequency cavity voltage, phase, and dipole magnet magnetic field. This process is time-consuming and requires highly skilled operators.

[0005] 2. Insufficient precision and efficiency: Manual control cannot guarantee high-precision energy adjustment and fast switching, and the beam energy dispersion and transmission efficiency may be limited;

[0006] 3. Low degree of automation: Traditional manual control methods are difficult to meet complex experimental requirements, such as continuously variable energy or multi-energy point irradiation experiments.

[0007] For example, in the study of low-energy fusion reactions in nuclear astrophysics, the ion beam energy needs to be rapidly switched to different energy points to fill the product curve in the Gamow energy region. At the same time, the experiment also requires that the beam energy spread be less than 0.3% and that the transmission efficiency be high to reduce beam losses. However, the current manual control method is time-consuming, often requiring half an hour of manual optimization for each energy point to meet the requirements. If the experimental terminal requires frequent energy adjustment, manual control methods become "inadequate". Not only does it consume human resources, but the accuracy of manual control is also difficult to maintain under high-intensity work. Therefore, there is an urgent need for a technology that can achieve automated and high-precision energy adjustment and control. Summary of the Invention

[0008] In view of the above problems, the object of the present invention is to provide a negative feedback automatic energy control device and method for a low-energy linear accelerator.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] A negative feedback automatic energy control device suitable for a low-energy linear accelerator includes: a first beam clinic chamber and a second beam clinic chamber, the first beam clinic chamber includes a first Faraday cage, the second beam clinic chamber includes a second Faraday cage, a mass spectrometry dipole magnet is arranged between the first beam clinic chamber and the second beam clinic chamber, the beam enters the mass spectrometry dipole magnet after passing through the first beam clinic chamber, the beam changes direction in the mass spectrometry dipole magnet, and enters the second beam clinic chamber after passing through the mass spectrometry dipole magnet, a first beam intensity is obtained by measuring the first Faraday cage in the first beam clinic chamber, and a second beam intensity is obtained by monitoring the second Faraday cage in the second beam clinic chamber, and the amplitude and phase parameters of the high-frequency cavity are dynamically adjusted by a negative feedback control algorithm until the second beam intensity is less than a first set ratio of the first beam intensity, and the first set ratio is 1%.

[0011] Preferably, a quarter-wavelength beam condenser is provided before the first beam clinic to suppress energy dispersion growth.

[0012] Preferably, a first slit is provided in the first beam examination chamber, and a second slit is provided in the second beam examination chamber. The first slit and the second slit are adjusted to a first opening (preferably ±1 mm). When the beam flows into the second Faraday cup of the second beam examination chamber, the beam intensity is recorded, the output power of the quarter-wavelength beam buncher is adjusted to a set value (preferably 500 watts), and the phase is scanned from 0 degrees to 360 degrees to find the phase value corresponding to the maximum current value of the second Faraday cup of the second beam examination chamber. Subsequently, the output power of the quarter-wavelength beam buncher is fine-tuned up and down (preferably with an adjustment step of about 50 watts each time), and the high-frequency parameters of the quarter-wavelength beam buncher are found based on the current reading of the second Faraday cup of the second beam examination chamber.

[0013] Preferably, a first beam position detector is provided at the entrance of the first beam examination room, and a second beam position detector is provided at the exit of the first beam examination room. The first beam position detector and the second beam position detector are separated by a distance of L. By collecting the flight time t of the beam from entering the first beam position detector to flying out of the second beam position detector, the flight speed v = L / t of the beam is calculated, so as to convert the speed into the energy of the beam using the kinetic energy formula.

[0014] Preferably, the second Faraday cage of the second beam examination room is a blocking Faraday cage, and the second beam examination room further comprises a two-dimensional double-wire detector for measuring the intensity of the deflected beam and measuring the beam profile to calculate energy deviation and beam energy dispersion.

[0015] A negative feedback automatic energy control method for a low-energy linear accelerator measures the first Faraday cup in the first beam clinic to obtain the beam intensity, and simultaneously monitors the signal of the second Faraday cup in the second beam clinic in real time to obtain the initial parameters of the high-frequency cavity.

[0016] Preferably, the amplitude is increased by a predetermined value (preferably 0.01 V) and the phase is scanned 360 degrees, and the automatic adjustment and scanning are performed. At the same time, it is automatically determined whether to continue the high-frequency parameter modulation according to the feedback signal of the first Faraday cup.

[0017] Preferably, when the second Faraday cup reads back the beam signal, data recording begins, and the high-frequency parameters are continuously step-modulated until the beam signal read after the parameters are adjusted is less than the first set ratio of the beam intensity, and the high-frequency cavity parameters corresponding to the maximum signal of the second Faraday cup are obtained, thereby ending energy regulation.

[0018] Preferably, when the fluctuation of the beam intensity is greater than a second set proportion (preferably 10%) of the maximum value of the beam signal, the current value of the mass spectrometer dipole magnet is first fine-tuned, first increasing and then decreasing by 1 ampere based on the original parameters, and the change in beam intensity is compared; if the beam intensity returns to the initial maximum value of the beam signal, it indicates that the beam energy has changed, and the energy calibration step will be performed at this time.

[0019] Preferably, the slit opening is first maintained at ±1 mm, and then the horizontal envelope of the bunch is scanned using a wire scanning detector. The energy divergence information of the beam is calculated using a correlation formula between the envelope and the system dispersion function to perform energy dispersion monitoring.

[0020] The present invention has the following advantages due to the adoption of the above technical solution:

[0021] 1. Improve experimental efficiency: Through automated control, manual operation time is significantly reduced and experimental efficiency is improved;

[0022] 2. Precise energy control: Automatically control beam energy, automatically detect energy accuracy and provide real-time feedback to the control system for energy fine-tuning;

[0023] 3. Optimize beam performance: reduce beam energy dispersion, improve transmission efficiency, and meet high-precision experimental requirements;

[0024] 4. Reduce labor costs: reduce manpower and material consumption through program control and automated operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. Throughout the drawings, the same reference numerals are used to denote the same components. In the drawings:

[0026] Figure 1 is a schematic structural diagram of an automatic energy control device according to an embodiment of the present application;

[0027] Figure 2 is a flow chart of an energy control method according to an embodiment of the present application; and

[0028] Figure 3 It is a flow chart of the energy dissipation control method according to an embodiment of the present application.

[0029] The symbols in the accompanying drawings represent the following:

[0030] Incremental energy linear accelerator (IDL) 1; quarter-wavelength buncher (QWR-Rebuncher) 2; first beam position detector (BPM-1) 3; first slit (S1) 4; first Faraday cage (FC1) 5; first beam clinic (beam clinic before deflection D1) 6; second beam position detector (BPM-2) 7; mass spectrometer dipole magnet (MSD) 8; second slit (S2) 9; wire scanning detector (WS) 10; second Faraday cage (FC2) 11; second beam clinic (beam clinic after deflection D2) 12. DETAILED DESCRIPTION

[0031] The exemplary embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art. Hereinafter, although examples of the present disclosure will be described in detail with reference to the accompanying drawings, it should be noted that the examples are not limited thereto.

[0032] The following detailed description is provided to help the reader gain a comprehensive understanding of the methods, devices and / or systems described herein. However, various changes, modifications and equivalents of the methods, devices and / or systems described herein will be apparent after understanding the present disclosure. For example, the order of operations described herein is merely an example, and except for operations that must occur in a specific order, it is not limited to the order set forth herein, but can be changed, which will be apparent after understanding the present disclosure. In addition, for the sake of clarity and brevity, descriptions of features that are well known in the art may be omitted.

[0033] The features described herein may be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided merely to illustrate some of the many possible ways to implement the methods, devices, and / or systems described herein that will be apparent after understanding the present disclosure.

[0034] Throughout the specification, when an element is described as being “on,” “connected to,” or “coupled to” another element, the element may be directly “on,” “connected to,” or “coupled to” the other element, or one or more other elements may be present between the element and the other element. Conversely, when an element is described as being “directly on,” “directly connected to,” or “directly coupled to” another element, there are no other elements between the element and the other element.

[0035] As used herein, the term "and / or" includes any one of the associated listed items and any combination of any two or more items; similarly, "at least one" includes any one of the associated listed items and any combination of any two or more items.

[0036] Although terms such as "first," "second," and "third" may be used herein to describe various members, components, regions, layers, or portions, these members, components, regions, layers, or portions are not limited by these terms. Rather, these terms are used only to distinguish one member, component, region, layer, or portion from another member, component, region, layer, or portion. Thus, without departing from the teachings of the examples described herein, a first member, first component, first region, first layer, or first portion mentioned in these examples may also be referred to as a second member, second component, second region, second layer, or second portion.

[0037] Spatially relative terms such as "above," "upper," "below," "lower," etc. may be used herein for descriptive convenience to describe the relationship of one element relative to another element as shown in the accompanying drawings. In addition to covering the orientations depicted in the accompanying drawings, these spatially relative terms are intended to cover different orientations of the device in use or operation. For example, if the device in the drawings is turned over, an element described as being "above" or "above" relative to another element will be "below" or "lower" relative to the other element. Thus, depending on the spatial orientation of the device, the term "above" covers both the orientations of "above" and "below." The device may also be oriented in other ways (e.g., rotated 90 degrees or in other orientations), and the spatially relative terms used herein should be interpreted accordingly.

[0038] The terms used herein are only used to describe various examples and are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the terms "a", "an", and "the" are intended to include plural forms as well. The terms "comprise", "include", and "have" indicate the presence of the stated features, numbers, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, components, elements, and / or combinations thereof.

[0039] Due to manufacturing techniques and / or tolerances, variations in the shapes shown in the drawings may occur. Therefore, the examples described herein are not limited to the specific shapes shown in the drawings but include variations in shapes that occur during manufacturing.

[0040] It should be noted that herein, use of the word “may” with respect to an example, for example, regarding what an example may include or implement, means that there is at least one example that includes or implements such feature, and all examples are not limited thereto.

[0041] The features of the examples described herein may be combined in various ways that will be apparent after understanding the present disclosure. In addition, although the examples described herein have various configurations, other configurations that will be apparent after understanding the present disclosure are also possible.

[0042] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a negative feedback automatic energy control device and method suitable for low-energy linear accelerators. Through multi-system collaboration, it can achieve automated beam energy adjustment, optimization, and detection to meet the needs of complex experiments. The present invention aims to achieve the following functions:

[0043] Automatic energy control: Based on negative feedback control technology, it realizes automatic switching of beam energy while optimizing beam energy dispersion and transmission efficiency;

[0044] High precision and high efficiency: Through real-time monitoring and feedback control, the beam energy dispersion is ensured to be less than 0.3% and the transmission efficiency is greater than 95%;

[0045] Adapt to complex experimental needs: Supports continuous multi-point automatic energy control (such as 0.3MeV / u to 1.0MeV / u), meeting the wide range of needs of nuclear astrophysics and nuclear energy materials experiments.

[0046] According to an embodiment of the present application, a negative feedback automatic energy control method applicable to a low-energy linear accelerator includes:

[0047] Energy regulation

[0048] As is well known, a charged ion beam subjected to a uniform magnetic field undergoes a series of physical processes, including deflection, focusing, and defocusing. The extent of these processes depends on the ions' magnetic stiffness, which in turn is determined by the ion species and their energy. Therefore, if ions are continuously transported during the energy change process, losses will inevitably occur, causing beam mismatch along its trajectory. To protect all equipment and cavities along the beam's path, the continuous wave beam must be switched to a pulsed beam before energy change to minimize equipment damage caused by beam mismatch. Commonly used pulsed beam parameters are a 1 Hz frequency and a 0.01% duty cycle.

[0049] The magnetic stiffness at the target ion energy is calculated and subsequently converted into the current value of the mass spectrometer dipole magnet (MSD) 8. First, the beam intensity I1 measured by the Faraday cup (FC1) 5 in the pre-deflection beam clinic (D1) 6 is measured, and the initial parameters a0 and p0 of the high-frequency cavity (incremental energy linear accelerator IDL) are set. Simultaneously, the monitoring system monitors the beam signal I2 from the barrier Faraday cup (FC2) 11 in the post-deflection beam clinic (D2) 12 in real time. The high-frequency control system automatically adjusts and scans the high-frequency cavity parameters, with the phase sweeping 360 degrees for every 0.01V increase in amplitude. The system also automatically determines whether to continue high-frequency parameter modulation based on the feedback signal from the Faraday cup. When the Faraday cup reads back the beam signal, data recording begins, and the high-frequency parameters are continuously step-modulated until the beam signal I2 read after the parameters are adjusted is less than 1% of the beam intensity I1. The high-frequency cavity parameters a1 and p1 corresponding to the maximum beam signal I2 are obtained, and the entire energy modulation process is complete.

[0050] Energy Monitoring

[0051] There are two ways to monitor energy:

[0052] First, energy is calculated using the TOF (time of flight) method using a beam position detector located in the pre-deflection beam clinic (D1) 6. The beam position detector consists of two parts: a first beam position detector (BPM-1) 3 and a second beam position detector (BPM-2) 7, located at the entrance and exit of the pre-deflection beam clinic (D1) 6, respectively, with a distance L between them. By measuring the flight time t of the beam from entering the first beam position detector (BPM-1) 3 to exiting the second beam position detector (BPM-2) 7, the beam's flight velocity v = L / t can be calculated. Finally, the velocity can be converted into beam energy using the kinetic energy formula.

[0053] Secondly, the beam intensity is continuously monitored using a second Faraday cage (FC2) 11 located in the pre-deflection beam clinic (D2) 12. When the beam intensity fluctuates by more than 10% of the maximum beam signal I2, the current of the mass spectrometer dipole magnet (MSD) 8 is fine-tuned by first increasing and then decreasing the current by 1 ampere from the original value, and the change in beam intensity is compared. If the beam intensity returns to the initial maximum value of the beam signal I2, this indicates a change in beam energy, and energy calibration is then performed.

[0054] Energy calibration

[0055] If beam energy deviates during operation, this may be due to a variety of factors, such as detuning of the high-frequency cavity, vacuum fluctuations, or water flow fluctuations. Automatic energy calibration is necessary. First, compare the cavity readback parameters with the set parameters a1 and p1 to ensure they match. Then, adjust the high-frequency parameters to restore the energy to normal.

[0056] Energy dispersion control

[0057] Due to the characteristics of the radio frequency accelerator, the heavy ion beam will obtain a large energy divergence after energy modulation, and the quarter-wavelength buncher (QWR-Rebuncher) 2 can be used to effectively suppress the growth of energy divergence. Due to the influence of energy divergence, the beam will grow in lateral dimension under the action of the dipole field. If the lateral dimension is larger than the pipeline limitation, loss will occur. Therefore, the regulation of energy divergence is based on this method. First, the first slit (S1) and the second slit (S2) in the pre-deflection beam clinic (D1) 6 and the post-deflection beam clinic (D2) 12 are adjusted to an opening of ±1mm. Then, the beam is passed into the second Faraday cage (FC2) 11 of the post-deflection beam clinic (D2) 12, and the beam intensity is recorded. The output power of QWR-Rebuncher 2 was then adjusted to approximately 500 watts, and the phase was swept from 0 to 360 degrees to find the phase value corresponding to the maximum current in the second Faraday cage (FC2) 11. The output power of QWR-Rebuncher 2 was then fine-tuned up and down, with each adjustment step being approximately 50 watts. The optimal high-frequency parameters of QWR-Rebuncher 2 were determined based on the current reading of the second Faraday cage (FC2) 11.

[0058] Energy dispersion monitoring

[0059] The heavy ion beam energy divergence is monitored using a combination of slits and a wire-scanning detector. The first slit 4 is kept open at ±1 mm, and the wire-scanning detector 10 is used to scan the horizontal envelope of the bunch to calculate the beam energy divergence.

[0060] According to an embodiment of the present application, a negative feedback automatic energy control device for a low-energy linear accelerator includes:

[0061] Pre-deflection beam clinic: The main components are a blocking Faraday cage, a double slit, and a beam position detector. Located before the dipole magnet, it is used to detect the beam intensity, transverse profile, and beam energy before being deflected by the dipole magnet.

[0062] Mass spectrometer dipole magnet: The main components are a dipole magnet and an embedded Hall probe system. They are used for beam deflection in orbit, magnetic field readback, and beam energy screening.

[0063] High-frequency cavity: The main components are a drift-tube linear accelerator and a quarter-wavelength buncher. They are used to switch beam energy and suppress beam energy dispersion.

[0064] Post-deflection beam clinic: The main components are a barrier Faraday cage and a two-dimensional wire scanning detector. They are used to measure the intensity of the deflected beam and the beam profile to calculate the energy deviation and beam energy dispersion.

[0065] Negative feedback control unit: The main components are the control system and feedback algorithm. By integrating these systems, real-time energy regulation and optimization can be achieved through multi-system collaboration.

[0066] Figure 1 It is a structural schematic diagram of an automatic energy control device according to an embodiment of the present application.

[0067] like Figure 1 As shown, the deflection pre-beam examination room, ie, the first beam examination room (D1) 6, includes a first Faraday cage (FC1) 5, a first slit (S1) 4 and beam position detectors (BPM-1 and BPM-2).

[0068] The first beam examination room (D1) 6 is located in front of the mass spectrometer dipole magnet (MSD) 8 and is used to detect the beam intensity, transverse profile and beam energy monitoring before being deflected by the mass spectrometer dipole magnet (MSD) 8.

[0069] The mass spectrometer dipole magnet (MSD) 8 includes a dipole magnet and an embedded Hall probe system, which is used for deflecting the beam in the track, reading back the magnetic field, and screening the beam energy.

[0070] The high-frequency cavity includes an incremental linear accelerator (IDL) 1 and a quarter-wavelength buncher (QWR-Rebuncher) 2, which are used to switch the beam energy and suppress the dispersion of the beam energy.

[0071] The post-deflection beam examination room, i.e., the second beam examination room (D2) 12, includes a second Faraday cage (FC2) 11, a second slit (S2) 9 and a wire scanning detector (WS) 10, which is used to measure the beam intensity after deflection and the beam profile to calculate the energy deviation and beam energy dispersion.

[0072] The negative feedback control unit includes a control system and a feedback algorithm, which realizes real-time energy regulation and optimization through multi-system collaboration.

[0073] Advantages of the automatic energy control device according to the embodiments of the present application include:

[0074] Automation: through program control, the ion beam energy can be automatically switched to reduce manual intervention;

[0075] High-precision, fast and stable automatic adjustment of beam energy to ensure energy accuracy while maintaining beam energy divergence within the optimal range;

[0076] High efficiency, real-time feedback mechanism ensures beam transmission efficiency is higher than 95% before and after deflection.

[0077] like Figure 2 This is a flow chart of the energy control method according to an embodiment of the present application. Figure 2 As shown, the energy control method process includes:

[0078] S1: Set beam energy

[0079] S2: Set the beam duty cycle to 0.01%

[0080] S3: Set the initial cavity parameters a0 and p0

[0081] S4: Calculate beam magnetic stiffness

[0082] S5: Switching magnet current

[0083] S6: Beamline Magnet Modulation

[0084] S7: Measure the initial beam intensity I1

[0085] S8: Cavity amplitude +0.01V

[0086] S9: Cavity phase 0-360 degree scan

[0087] S10: Record FC2 beam intensity I2

[0088] S11: Find the peak intensity of FC2 beam

[0089] S12: Record and set the high-frequency parameters a1 and p1 at the peak value.

[0090] Figure 3 This is a flow chart of the energy dissipation control method according to an embodiment of the present application. Figure 3 As shown, the energy dispersion control method process includes:

[0091] S13: Adjust the slits S1 and S2 to ±1mm

[0092] S14: Record the beam intensity of FC2

[0093] S15: Set the initial buncher parameters to 500W and 0 degrees

[0094] S16: Cavity phase 0-360 degree scan

[0095] S17: Record the change of FC2 current intensity readback value with cavity phase

[0096] S18: Find the cavity phase P1 that maximizes the FC2 flow intensity.

[0097] S19: Maintain P1 and fine-tune the cavity power up and down, with a step size of 50W

[0098] S20: Find the optimal parameters of the buncher and set them.

[0099] Although specific examples have been shown and described above, it will be apparent after understanding this disclosure that various changes in form and detail may be made to these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be understood in a descriptive sense only and not for purposes of limitation. The description of features or aspects in each example should be considered applicable to similar features or aspects in other examples. Appropriate results may still be achieved if the described techniques are performed in a different order, and / or if components in the described systems, architectures, devices, or circuits are combined in different ways and / or replaced or supplemented by other components or their equivalents. Therefore, the scope of this disclosure is not limited by the specific embodiments, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents should be understood to be included in this disclosure.

[0100] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A negative feedback automatic energy control device suitable for a low-energy linear accelerator, characterized in that: The invention comprises a first beam clinic chamber and a second beam clinic chamber, wherein the first beam clinic chamber comprises a first Faraday cup, and the second beam clinic chamber comprises a second Faraday cup. A mass spectrometry dipole magnet is arranged between the first beam clinic chamber and the second beam clinic chamber. The beam enters the mass spectrometry dipole magnet after passing through the first beam clinic chamber, where the beam changes direction. The beam enters the second beam clinic chamber after passing through the mass spectrometry dipole magnet. The first beam intensity is obtained by measuring the first Faraday cup in the first beam clinic chamber, and the second beam intensity is obtained by monitoring the second Faraday cup in the second beam clinic chamber. The amplitude and phase parameters of the high-frequency cavity are dynamically adjusted by a negative feedback control algorithm until the second beam intensity is less than a first set ratio of the first beam intensity.

2. The negative feedback automatic energy control device for a low-energy linear accelerator according to claim 1, characterized in that: A quarter-wavelength beam condenser is provided before the first beam examination room to suppress energy dispersion growth.

3. The negative feedback automatic energy control device for a low-energy linear accelerator according to claim 2, characterized in that: A first slit is provided in the first beam examination chamber, and a second slit is provided in the second beam examination chamber. The first slit and the second slit are adjusted to a first opening. When the beam flows into the second Faraday cup of the second beam examination chamber, the beam intensity is recorded, the output power of the quarter-wavelength buncher is adjusted to a set value, the phase is scanned from 0 degrees to 360 degrees, and the phase value corresponding to the maximum current value of the second Faraday cup of the second beam examination chamber is found. Then, the output power of the quarter-wavelength buncher is fine-tuned up and down, and the high-frequency parameters of the quarter-wavelength buncher are found based on the current back reading of the second Faraday cup of the second beam examination chamber.

4. The negative feedback automatic energy control device for a low-energy linear accelerator according to claim 1, characterized in that: A first beam position detector is provided at the entrance of the first beam examination room, and a second beam position detector is provided at the exit of the first beam examination room. The first beam position detector and the second beam position detector are separated by a distance L. By collecting the flight time t of the beam from entering the first beam position detector to flying out of the second beam position detector, the flight velocity v = L / t of the beam is calculated, and the velocity is converted into beam energy using the kinetic energy formula.

5. The negative feedback automatic energy control device for a low-energy linear accelerator according to claim 1, characterized in that: The second Faraday cage of the second beam examination room is a blocking Faraday cage. The second beam examination room also includes a two-dimensional double-wire detector for measuring the intensity of the deflected beam and measuring the beam profile to calculate energy deviation and beam energy dispersion.

6. A negative feedback automatic energy control method for a low-energy linear accelerator, using the negative feedback automatic energy control device for a low-energy linear accelerator according to any one of claims 1 to 5, characterized in that: The first Faraday cup in the first beam examination room is measured to obtain the beam intensity, and the signal of the second Faraday cup in the second beam examination room is monitored in real time to obtain the initial parameters of the high-frequency cavity.

7. The negative feedback automatic energy control method for a low-energy linear accelerator according to claim 6, characterized in that: The amplitude is automatically adjusted and scanned in a manner of increasing by a predetermined value and scanning the phase by 360 degrees, and whether to continue the high-frequency parameter modulation is automatically determined according to the feedback signal of the first Faraday cup.

8. The negative feedback automatic energy control method for a low-energy linear accelerator according to claim 6, characterized in that: When the second Faraday cup reads back the beam signal, data recording begins, and high-frequency parameters are continuously step-modulated until the beam signal read after the parameters are adjusted is less than the first set ratio of the beam intensity, thereby obtaining the high-frequency cavity parameters corresponding to the maximum signal of the second Faraday cup and ending energy regulation.

9. The negative feedback automatic energy control method for a low-energy linear accelerator according to claim 6, characterized in that: When the fluctuation of the beam intensity is greater than the second set ratio of the maximum value of the beam signal, the current value of the mass spectrometer dipole magnet is first fine-tuned, first increasing and then decreasing by 1 ampere based on the original parameter, and the change in beam intensity is compared; if the beam intensity returns to the initial maximum value of the beam signal, it indicates that the beam energy has changed, and the energy calibration step will be performed at this time.

10. The negative feedback automatic energy control method for a low-energy linear accelerator according to claim 6, characterized in that: First, the slit opening is kept at ±1mm, and then the horizontal envelope of the bunch is scanned using a wire scanning detector. The energy divergence information of the beam is calculated using the correlation formula between the envelope and the system dispersion function for energy dispersion monitoring.

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