Beam homogenization control method, system and electronic device in a circular region

Abstract

The present application relates to the technical field of accelerator high-current particle beam, and provides a kind of circular area beam uniformization control method, system and electronic equipment, comprising: obtaining target beam spot size and the target scanning parameter of multi-order sinusoidal wave superposition trajectory model;According to target beam spot size, control focusing element group to initial particle beam is carried out transverse focusing, so that the focused particle beam forms smaller beam spot at target surface;According to target scanning parameter, control scanning element group is carried out transverse scanning to focused particle beam according to multi-order sinusoidal wave superposition trajectory model, so that particle beam forms circular distribution at target surface.The present application realizes the efficient uniformization of high-power particle beam in circular target surface area by using the trajectory model composed of mutually orthogonal multi-order sinusoidal wave components for transverse scanning control of particle beam, and greatly reduces the peak flow intensity density, so as to be able to adapt to circular distribution boundary constraint, and scanning waveform is easy to implement in engineering and can prolong the service life of terminal equipment.

Description

Technical Field

[0001] This invention relates to the field of high-current particle beam technology for accelerators, and more particularly to a method, system, and electronic device for beam homogenization control within a circular region. Background Technology

[0002] In the field of high-current particle beam technology for accelerators, the beam exiting the accelerator typically exhibits a two-dimensional Gaussian distribution across its cross-section, with extremely high flux density near the beam center. Excessive flux density can lead to severe problems such as heat removal, thermal stress, and irradiation damage in the target acquisition equipment, thereby significantly shortening its lifespan. Therefore, transverse scanning of the particle beam is usually necessary to achieve beam homogenization.

[0003] Currently, existing beam homogenization schemes all have certain limitations. For example, some conventional schemes use high-order magnets or triangular wave Lissajous scanning to achieve beam homogenization. However, such schemes are only applicable to rectangular regions and are not suitable for terminals where the beam distribution boundary needs to be circular due to manufacturing processes or physical requirements.

[0004] To accommodate a circular target surface, some solutions employ two orthogonal scanning magnets to achieve a ring-shaped beam distribution. However, for terminals with stringent requirements on peak current density and the proportion of beam halo particles outside the target (i.e., beam loss outside the target), this ring-shaped scanning mechanism often cannot simultaneously meet these requirements.

[0005] In addition, some solutions attempt to achieve homogenization by using a spiral swing scanning method within a circular area, but the scanning waveform required by this solution is extremely complex and difficult to achieve stably using current power supply equipment technology, thus lacking engineering feasibility. Summary of the Invention

[0006] This invention provides a method, system, and electronic device for beam homogenization control within a circular region, which addresses the shortcomings of existing technologies in beam homogenization scanning within a circular region, namely, the difficulty in effectively reducing peak current density, meeting stringent external beam loss limits, and the high difficulty in achieving engineering waveforms.

[0007] This invention provides a method for beam homogenization control within a circular region, comprising: Obtain the target beam size and target scanning parameters of the multi-order sinusoidal wave superposition trajectory model, wherein the multi-order sinusoidal wave superposition trajectory model is composed of the superposition of multi-order scanning waveforms, and each order of scanning waveform contains two sets of sinusoidal wave components that are orthogonal to each other in the horizontal and vertical directions; Based on the target beam size, the focusing element group is controlled to perform lateral focusing on the initial particle beam, so that the focused particle beam forms a smaller beam spot at the target surface. According to the target scanning parameters, the scanning element group is controlled to perform a lateral scan on the focused particle beam according to the multi-order sine wave superposition trajectory model, so that the particle beam forms a circular distribution on the target surface.

[0008] According to the present invention, a method for beam homogenization control within a circular region, wherein obtaining the target beam spot size and target scanning parameters of a multi-order sinusoidal wave superposition trajectory model includes: Obtain the target surface constraints; Under the constraints of the target surface, the initial beam spot size and the initial scanning parameters of the multi-order sinusoidal wave superposition trajectory model are optimized to obtain the target beam spot size and the target scanning parameters.

[0009] According to the present invention, a method for beam homogenization control within a circular region includes target surface constraints such as target surface size, upper limit of peak current density at the target surface, and external beam loss constraints. Under the constraints of the target surface constraints, the initial beam spot size and the initial scanning parameters of the multi-order sinusoidal wave superposition trajectory model are optimized to obtain the target beam spot size and the target scanning parameters, including: Establish the beam halo distribution boundary constraint relationship between the initial beam spot size and the maximum scanning radius, and determine the beam halo distribution boundary constraint relationship as the target external beam loss constraint condition; Using the peak beam current density at the target surface as the optimization objective, and under the constraints of the beam loss outside the target and the upper limit of the peak beam current density at the target surface, a global optimization algorithm is used to optimize the initial beam spot size and the initial scanning parameters to obtain the target beam spot size and the target scanning parameters.

[0010] According to the present invention, a method for controlling beam homogenization within a circular region, wherein establishing the beam halo distribution boundary constraint relationship between the initial beam spot size and the maximum scanning radius includes: The halo adjustment coefficient is determined based on the proportion of particle power outside the target surface, the beam energy, and the accelerator error. Based on the initial beam spot size, the target surface size, the maximum scanning radius, and the beam halo adjustment coefficient, the beam halo distribution boundary constraint relationship is constructed. The constructed beam halo distribution boundary constraint relationship is as follows: the sum of the products of the maximum scanning radius, the beam halo adjustment coefficient, and the initial beam spot size is less than or equal to the target surface size.

[0011] According to the present invention, a method for beam homogenization control within a circular region includes the following steps in constructing the multi-order sinusoidal wave superposition trajectory model: The sinusoidal components corresponding to the multi-order scanning waveforms are linearly superimposed to obtain the coordinate relationship of the position of the beam spot center on the target surface as a function of time. Based on the coordinate relationship, the multi-order sinusoidal wave superposition trajectory model is obtained.

[0012] According to the present invention, a method for beam homogenization control within a circular region, wherein the sinusoidal components corresponding to the multi-order scanning waveforms are linearly superimposed to obtain a coordinate relationship of the beam spot center position on the target surface as a function of time, includes: The horizontal position coordinate variation formula is obtained by summing the product of the scanning amplitude of each scanning waveform and the cosine function of the corresponding scanning angular frequency. The vertical position coordinate variation formula is obtained by summing the product of the scanning amplitude of each scanning waveform and the sine function of the corresponding scanning angular frequency. By combining the horizontal position coordinate transformation formula and the vertical position coordinate transformation formula, the two-dimensional coordinate relationship formula is obtained; The target scanning parameters include the scanning angular frequency and scanning amplitude of each order of scanning waveform.

[0013] According to the present invention, a method for controlling beam homogenization within a circular region, wherein controlling the focusing element group to laterally focus an initial particle beam based on the target beam spot size includes: The focusing element group, consisting of multiple quadrupole magnets or solenoids, is controlled to constrain the envelope of the initial particle beam in the cross-sectional direction, so that the root mean square dimension of the constrained initial particle beam at the target surface is equal to the target beam spot size.

[0014] According to a method for beam homogenization control within a circular region provided by the present invention, after the step of controlling the focusing element group composed of multiple quadrupole magnets or solenoids to constrain the envelope of the initial particle beam in the cross-sectional direction, the method further includes: When there is a specific incident direction requirement for the beam, the diode magnet is controlled to deflect the constrained initial particle beam, thereby changing the incident direction of the initial particle beam and enabling the initial particle beam to hit the target.

[0015] The present invention also provides a beam homogenization control system within a circular region, comprising: The focusing element group is configured to laterally focus the initial particle beam; A scanning element group, located downstream of the focusing element group, is configured to perform a lateral scanning of the focused particle beam. The controller is communicatively connected to the focusing element group and the scanning element group, respectively, and is used to execute the beam homogenization control method in the circular region as described above.

[0016] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the beam homogenization control method in the circular region as described above.

[0017] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the beam homogenization control method in the circular region as described above.

[0018] The present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the beam homogenization control method within a circular region as described above.

[0019] The present invention provides a method, system, and electronic device for beam homogenization control within a circular region. First, an initial particle beam is laterally focused using a focusing element group, providing a basic beam conforming to the target size for subsequent precise scanning. Then, a unique multi-order sine wave superposition trajectory model is used to control the scanning element group for lateral scanning. Since this model is composed of multiple orders of mutually orthogonal sine wave components in the horizontal and vertical directions, it enables the beam spot center to rotate angularly around the target surface while simultaneously achieving multi-dimensional radial modulation. This uniformly spreads the initially Gaussian-distributed high-current particle beam across the entire circular target area laterally. This not only meets the requirement of a circular beam distribution boundary for specific terminals but also effectively overcomes the problems of excessive emptiness in the target center region or excessively high peak flux density that are easily caused by traditional single-order sine wave ring scanning. This significantly reduces the peak flux density at the target surface, alleviates the thermal removal problem and irradiation damage risk caused by extremely high flux, and significantly extends the service life of the terminal equipment. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is one of the flowcharts illustrating the beam homogenization control method within a circular region provided by the present invention; Figure 2This is the second flowchart of the beam homogenization control method within a circular region provided by the present invention; Figure 3 This is a radial cross-sectional view of the beam spot distribution at the target surface before large beam spot scanning provided by the present invention; Figure 4 This is a radial cross-sectional view of the beam spot distribution at the target surface before small beam spot scanning provided by the present invention; Figure 5 This is a three-dimensional image of the beam spot distribution at the target surface of the preferred scanning scheme provided by the present invention; Figure 6 This is a radial cross-sectional view of the beam spot distribution at the target surface in the preferred scanning scheme provided by the present invention; Figure 7 This is a schematic diagram of the beam homogenization control system within a circular region provided by the present invention; Figure 8 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0023] To facilitate understanding of the technical solutions provided by this invention, some key terms involved in this invention will first be explained.

[0024] An accelerator is a device that uses electromagnetic fields to propel charged particles to extremely high speeds and energy states. Its core function is to provide particles with the ability to move in a high-energy state so that these high-energy particles can be used for subsequent scientific research experiments, medical or industrial applications.

[0025] An accelerator high-current particle beam is a directed particle stream generated by a high-current accelerator, characterized by high flux intensity (i.e., a huge number of particles per unit time) and extremely high total power. It carries extremely high total energy and heat, and produces intense physical or chemical reactions when interacting with matter.

[0026] The accelerator exit beam refers to the initial beam of a particle beam that has just completed its acceleration process, left the main accelerator equipment, but has not yet been scanned by the downstream complex transmission lines or interacted with the target. It represents the most primitive spatial and energy distribution of the particle beam before entering the terminal, and typically exhibits a highly concentrated two-dimensional Gaussian distribution at the center.

[0027] The beam spot center refers to the geometric or energy center of the illumination pattern (i.e., beam spot) formed by a particle beam striking a cross-section (such as a target surface). In an unhomogenized Gaussian beam, the beam spot center is usually the core location where the particles are most concentrated and the flux density is highest.

[0028] Beam size refers to the macroscopic physical range or geometric size of a particle beam in the lateral spatial distribution when it hits a cross-section (such as a target surface).

[0029] Beam current intensity generally refers to the average current intensity of the beam, which is the total amount of macroscopic charge passing through the cross-section of the particle beam per unit time. It reflects the overall macroscopic current intensity of the particle beam and is a fundamental indicator for measuring the output capability of an accelerator beam.

[0030] Flux density generally refers to the surface flux density of a beam (commonly measured in μA / cm²). 2 Peak current density (PHD) refers to the beam current intensity per unit cross-sectional area. In particular, PHD directly determines the maximum heat load and extreme value of irradiation damage borne by a local area of ​​the target surface, and is a key parameter limiting the lifespan of terminal equipment.

[0031] Terminal equipment refers to a complete set of physical devices installed at the very end of a particle beam transmission line for receiving and utilizing the beam. For example, terminal equipment may include the target itself, as well as physical hardware that directly interacts with the beam, such as upstream beam windows and target windows.

[0032] The target surface refers to the geometric surface or region on the target body in the terminal equipment that directly encounters the incident particle beam. As the area where the beam directly interacts, the target surface needs to fully absorb the energy deposition of the high-current particle beam, thus requiring extremely high uniformity of the current density distribution on it.

[0033] In the field of high-current particle beam targeting applications in accelerators, the accelerator exit beam typically exhibits a two-dimensional Gaussian distribution across its cross-section. This distribution characteristic results in extremely high flux density near the beam center. For example, with a 5 mA continuous wave beam and a root-mean-square dimension σ = 15 mm, the flux density at the center can reach as high as 354 μA / cm². 2 Here, the root mean square (RMS) dimension is a statistical mathematical indicator used to accurately quantify the lateral beam distribution width. Whether considering heat removal and thermal stress effects on the target, or irradiation damage effects, the extremely high flux density at the center often far exceeds the upper limit that the target material can withstand, easily leading to damage to the terminal equipment and severely shortening its service life. Therefore, it is necessary to use beam homogenization technology to laterally flatten the high-power particle beam at the target surface to reduce the peak flux density at the target surface.

[0034] Currently, several traditional scanning schemes are commonly used to achieve beam homogenization, but these schemes all have certain limitations. The first scheme uses a focusing element group to focus the beam into a small spot at the target surface, and then uses a high-order magnet or triangular-wave Lissajous scanning to achieve beam homogenization within a rectangular region, thereby reducing the peak beam current density. The drawback of this scheme is that it is only applicable to rectangular target areas. In practical engineering applications, many terminals need to ensure isotropic beam distribution in the lateral direction, or, due to limitations in target manufacturing processes, objectively require a circular beam distribution boundary. Therefore, this rectangular scanning method is completely unsuitable for terminals requiring circular beam distribution.

[0035] The second approach utilizes two orthogonal scanning magnets to achieve a ring-shaped beam distribution. The magnetic field waveforms in both directions are sinusoidal with a 90° phase difference, causing the beam center to periodically and uniformly scan along a circle of fixed radius on the target surface, resulting in a circular beam distribution boundary. However, this single ring-shaped scanning method is inherently contradictory due to the strict constraints of target size and the halo around the target. If the beam size is too large, the scanning radius must be reduced due to the boundary size, leading to a deterioration in overall scanning homogenization. If the beam size is too small, although the scanning radius can be increased, the beam distribution on the target surface becomes too sparse in the central region, resulting in a still high peak flux density in the ring. Therefore, for terminals with stringent requirements on peak flux density and the proportion of halo particle power (beam loss outside the target), this conventional ring-shaped scanning method often fails to meet practical needs.

[0036] To further improve uniformity within the circular region, a third approach is to employ a helical swing scanning method, which involves superimposing radial modulation on an angular rotation at the beam spot center (achieved by using a scanning radius proportional to the square root of time). However, this method requires an extremely complex scanning magnetic field waveform, and relying on existing power supply technology in the engineering field makes it difficult to stably and accurately output such complex waveforms, resulting in extremely high implementation difficulty and a lack of feasibility for engineering application.

[0037] To address this, the present invention provides a method for beam homogenization control within a circular region to overcome the aforementioned defects. Figure 1 This is one of the flowcharts illustrating the beam homogenization control method within a circular region provided by the present invention, such as... Figure 1 As shown, the method includes: Step S10: Obtain the target beam size and target scanning parameters of the multi-order sine wave superposition trajectory model. The multi-order sine wave superposition trajectory model is composed of superimposed multi-order scanning waveforms, and each scanning waveform contains two sets of sine wave components that are orthogonal to each other in the horizontal and vertical directions.

[0038] Specifically, the target beam spot size typically refers to the root mean square size of the Gaussian distribution of the beam across its cross-section, generally denoted by σ. Obtaining this size provides target parameters for the focusing step at the front end. Conventional accelerator exit beams generally exhibit a two-dimensional Gaussian distribution across their cross-section. In the initial, unprocessed state, the flux density near the beam spot center is extremely high, far exceeding the upper limit that the target surface can withstand. To reduce the flux density and meet the requirement of certain terminals for a circular beam distribution boundary, this embodiment of the invention introduces a multi-order sinusoidal wave superposition trajectory model. This trajectory model is essentially a mathematical control logic used to guide the subsequent scanning path of the beam spot center.

[0039] Understandably, in existing technologies, while using only two orthogonal scanning magnets to achieve a single-order sinusoidal wave scan (i.e., a simple circular scan) can result in a circular boundary, it cannot meet the stringent requirements of some terminals regarding peak flux density and the proportion of target halo particles power. Therefore, the model in this embodiment of the invention employs a multi-order scanning waveform superposition method.

[0040] Specifically, each additional scanning waveform introduces a set of sinusoidal components orthogonal in the horizontal and vertical directions (with a 90° phase difference). In practical control principles, this multi-order superposition mechanism can be described as the change in the position (coordinates) of the beam spot center on the target surface over time t being a linear superposition of the sinusoidal waves of each order in the corresponding directions. For example, the horizontal position change equals the sum of the products of the scanning amplitude of each order and its corresponding scanning angular frequency cosine function, while the vertical change corresponds to the sum of the products of sine functions. Based on this model, the obtained target scanning parameters mainly include specific parameters that determine each order of sinusoidal wave, such as the scanning angular frequency and scanning amplitude corresponding to each waveform.

[0041] Step S20: Based on the target beam size, control the focusing element group to laterally focus the initial particle beam so that the focused particle beam forms a smaller beam spot at the target surface.

[0042] Specifically, since the final homogenization effect of the beam at the target surface is highly dependent on the initial beam shape before scanning, it is necessary to use a focusing element group to perform lateral envelope constraint on the initial particle beam in advance. This focusing element group is typically composed of a series of magnetic elements, such as, but not limited to, quadrupole magnets or solenoids. After receiving instructions from the control unit, it can generate a specific magnetic field to constrain the divergence of the high-current, high-power particle beam, so that when the particle beam reaches the target surface, its lateral root-mean-square size exactly matches the target beam spot size obtained above. In other words, in order to achieve a high degree of homogenization in the final circular region, the implementation principle of this step is to focus first and then scan, that is, to control the focusing element group to laterally focus the particle beam, so that the particle beam forms a smaller beam spot at the target surface, laying a foundation for precise coating downstream.

[0043] Step S30: According to the target scanning parameters, control the scanning element group to perform a lateral scan on the focused particle beam according to the multi-order sine wave superposition trajectory model, so that the particle beam forms a circular distribution on the target surface.

[0044] Specifically, after obtaining a focused particle beam, the system sends the acquired target scanning parameters to the scanning element group. This scanning element group is a hardware device that directly acts on the beam to deflect its position, such as using a system of multiple orthogonal scanning magnets.

[0045] Driven by a multi-order sinusoidal superposition trajectory model, the magnetic field waveform generated by the scanning element group strictly follows the superposition law of multi-order orthogonal sinusoidal components. This causes the beam spot center to rotate angularly along the target surface while being continuously modulated radially. This composite motion in a two-dimensional plane ensures that the smaller beam spot after focusing is evenly spread out laterally. Ultimately, this not only ensures that the beam distribution boundary in the cross-sectional direction is circular, but also effectively fills the central void that is easily generated by traditional single-order ring scanning.

[0046] The method provided in this invention uses a focusing element group to laterally focus an initial particle beam, providing a basic beam current that conforms to the target size for subsequent precise scanning. Then, a unique multi-order sine wave superposition trajectory model is used to control the scanning element group for lateral scanning. Since this model is composed of multiple orders of mutually orthogonal sine wave components in the horizontal and vertical directions, it enables the beam spot center to rotate angularly around the target surface while simultaneously achieving multi-dimensional radial modulation. This uniformly spreads the initially Gaussian-distributed high-current particle beam across the entire circular target area laterally. This not only meets the requirement of a specific terminal for a circular beam distribution boundary but also effectively overcomes the problems of excessive emptiness in the target center area or excessively high peak flux density that are easily caused by traditional single-order sine wave ring scanning. This significantly reduces the peak flux density at the target surface, alleviating the thermal removal problem and irradiation damage risk caused by extremely high flux, thereby improving the service life of the terminal equipment.

[0047] Based on the above embodiments, step S10 specifically includes: Step S11: Obtain the target surface constraint conditions.

[0048] Specifically, target surface constraints refer to the objective limitations imposed on accelerator terminal equipment during actual operation due to factors such as physical materials, manufacturing processes, and safety protection. As the area directly affected by the beam, the target surface must ensure that the beam distribution boundary in the cross-sectional direction is circular, and the stress and thermal load that the target surface itself can withstand are limited. Therefore, control schemes need to be designed under the constraints of these objective physical boundaries.

[0049] Step S12: Under the constraints of the target surface, optimize the initial beam spot size and the initial scanning parameters of the multi-order sinusoidal wave superposition trajectory model to obtain the target beam spot size and the target scanning parameters.

[0050] Specifically, the initial beam size and initial scanning parameters can be understood as the initial values ​​or search starting point when the optimization algorithm starts. Since the parameter combination space of multi-order sine waves is huge, not any set of parameters can produce a beam distribution that meets the terminal constraints at the target surface. Therefore, the system needs to find the optimal parameter combination by continuously iterating and adjusting the above initial parameters within the framework of ensuring that it does not break through the various hard constraints of the target surface (i.e., under the constraint of the target surface size). The output of this combination is then determined as the target beam size and target scanning parameters used for actual control.

[0051] The method provided in this invention avoids the risk of target damage caused by blindly setting scanning waveforms by introducing target surface constraints and performing targeted parameter optimization. It ensures that the final determined target beam size and target scanning parameters can achieve circular uniformity in theory and meet the load-bearing limits of different accelerator terminals in the actual physical environment, thereby improving the safety and engineering applicability of the control method.

[0052] Based on any of the above embodiments, the target surface constraints include target surface size, upper limit of target surface peak current density, and external beam loss constraints.

[0053] Specifically, the target surface size is usually expressed as a diameter (e.g., D), representing the circular physical boundary of effective target engagement. The upper limit of the target surface peak current density refers to the maximum beam current density (generally expressed in μA / cm²) that the terminal target material (including the target itself and upstream beam windows, target windows, and other terminal equipment) can withstand per unit area without overheating damage or severe irradiation damage. 2 (This is indicated by the text). The external beam loss constraint is to control the proportion of halo particles that extend beyond the target surface, preventing these high-energy particles from hitting the external structure of the target and causing power loss and equipment damage.

[0054] Under the specific constraints described above, the process of implementing parameter optimization (i.e., step S12) specifically includes: Step S121: Establish the beam halo distribution boundary constraint relationship between the initial beam spot size and the maximum scanning radius, and determine the beam halo distribution boundary constraint relationship as the target external beam loss constraint condition.

[0055] Specifically, the maximum scan radius (which can be expressed as...) The maximum distance between the beam spot center and the target surface center during multi-order ring scan superposition is referred to as the maximum distance. For multi-order sinusoidal scans, the maximum scan radius is essentially equal to the sum of the amplitudes of each scan. Since the beam is usually distributed in a two-dimensional Gaussian pattern in the transverse direction, with a widely distributed halo, the actual particle distribution range will be larger than the location of the beam spot center. Therefore, the established halo distribution boundary constraint relationship needs to limit the overall range of the beam spot center position after halo expansion to within the target surface size. This constraint relationship ensures that the outermost beam spot center plus the halo diffusion range is still strictly controlled, thus transforming the abstract off-target loss into a calculable position and size constraint boundary in the mathematical model.

[0056] Step S122: Using the peak beam current density at the target surface as the optimization target, and under the constraints of the beam loss outside the target and the upper limit of the peak beam current density at the target surface, the initial beam spot size and the initial scanning parameters are optimized using a global optimization algorithm to obtain the target beam spot size and the target scanning parameters.

[0057] Specifically, in this step, the system takes the minimum peak flow intensity density as the objective of multi-parameter single-objective global optimization, and uses a global optimization algorithm (such as particle swarm optimization algorithm, population optimization algorithm, etc.) to perform a large-scale search in the feasible solution space.

[0058] For example, in a specific application scenario, assuming a proton beam energy of 500 MeV, a continuous wave beam current of 5 mA, and a circular target size D = 250 mm, the peak beam current density at the target surface after scanning is required to be no higher than 35 μA / cm². 2 The beam power outside the target beyond Φ250 does not exceed 10 W. Without scanning, the flux density at the target center can reach as high as 354 μA / cm². 2 Through the global optimization algorithm in this step, under the rigid constraints of the beam halo distribution boundary, the algorithm automatically adjusts the scanning radius and scanning frequency of each order to match the required beam spot size (usually its root mean square size σ). Considering factors such as beam spot size matching and measurement, and scanning magnet technology, the actual parameters are often chosen as discrete points. The final algorithm outputs a set of optimal solutions that minimize the peak current density, which represents the desired target beam spot size and target scanning parameters.

[0059] The method provided in this invention transforms complex physical constraints into clear boundary constraints and uses a global optimization algorithm to find the lowest peak flux density. Under the premise of effectively preventing beam loss, it reduces the local thermal load and stress impact of the beam on the target surface to the lowest limit, achieving the optimal lateral energy flattening and coating effect, thereby improving the service life and operational reliability of the high-current accelerator terminal equipment.

[0060] Based on any of the above embodiments, step S121, establishing the beam halo distribution boundary constraint relationship between the initial beam spot size and the maximum scanning radius, includes: The halo adjustment coefficient is determined based on the proportion of particle power outside the target surface, the beam energy, and the accelerator error. Based on the initial beam spot size, the target surface size, the maximum scanning radius, and the beam halo adjustment coefficient, the beam halo distribution boundary constraint relationship is constructed. The constructed beam halo distribution boundary constraint relationship is as follows: the sum of the products of the maximum scanning radius, the beam halo adjustment coefficient, and the initial beam spot size is less than or equal to the target surface size.

[0061] Specifically, the halo adjustment factor (denoted by N) is a constant used to define the effective control range of the outer diverging portion (i.e., halo) of a Gaussian distributed beam. Since the actual particle beam exhibits a Gaussian distribution laterally, its edges theoretically extend infinitely. Therefore, truncation calculations are needed based on the actual tolerable percentage of halo particle power outside the target surface. Furthermore, considering that even a small portion of the overflowing halo particles can carry enormous power at high beam energies, causing thermal or irradiation damage to the target structure, and that accelerator errors during system operation often lead to further halo growth and minor jitter at the beam center, this adjustment factor needs to be determined by comprehensively considering these various physical and engineering factors.

[0062] In practice, to effectively reduce the proportion of power of particles in the halo outside the target, the value of N is generally above 3. However, when the beam energy is high, especially considering accelerator error, N is often taken as 5 or higher. For example, in the scenario of a proton beam energy of 500 MeV and a continuous wave beam current of 5 mA, N can be conservatively taken as 8.

[0063] Maximum scan radius (which can be expressed as) The initial beam spot size (typically represented by σ) characterizes the maximum distance the beam spot center deviates from the target center during multi-order sinusoidal wave superposition scanning; the initial beam spot size (typically represented by σ) characterizes the root mean square size of the transverse Gaussian distributed beam. Therefore, the boundary constraint relationship of the beam halo distribution (i.e., the external beam loss constraint condition) can be expressed as follows: , where D is the target surface size.

[0064] The above constraint relationship represents the farthest limit position from the target center that the beam spot center can reach at the target surface, regardless of the complexity of the scanning trajectory (i.e., In addition to the safety buffer distance for the radial outward expansion of the halo at that location (i.e., the product of N and σ), the sum of these two must be strictly contained within the physical size range (D) at the target surface.

[0065] The method provided in this invention introduces a beam corona adjustment coefficient that comprehensively considers real physical boundary factors such as beam energy, power ratio, and accelerator error. This transforms the abstract external beam loss constraint into a simple and computationally efficient linear inequality constraint. This not only facilitates the boundary constraints of subsequent global optimization algorithms when optimizing parameters and improves the optimization efficiency and reliability of the algorithm, but also avoids the risk of damage to external equipment of the target due to beam loss.

[0066] Based on any of the above embodiments, the steps for constructing the multi-order sinusoidal wave superposition trajectory model include: The sinusoidal components corresponding to the multi-order scanning waveforms are linearly superimposed to obtain the coordinate relationship of the position of the beam spot center on the target surface as a function of time. Based on the coordinate relationship, the multi-order sinusoidal wave superposition trajectory model is obtained.

[0067] Specifically, the multi-order scanning waveform is composed of multiple single-order waveforms, each responsible for providing a reference rotational scanning motion at a specific radius. Since scanning typically occurs in a two-dimensional plane, each order waveform is decomposed into two sets of sinusoidal components in two mutually orthogonal directions (usually horizontal and vertical, with a phase difference of 90°). The system calculates the coordinate relationship of the particle beam spot center at the target surface as it changes over time by linearly superimposing these components from different orders in corresponding directions (i.e., directly summing the values ​​of each order component at the same time point). This coordinate relationship can be expressed as follows: in, and This indicates the position of the beam spot center on the target surface over time. Changes, The scanning angular frequency, This is for scanning amplitude.

[0068] The dynamic coordinate change law obtained by linear superposition forms a virtual smearing path describing the continuous motion of the beam spot center. This path model is the multi-order sinusoidal superposition trajectory model that is ultimately used to guide the scanning element (such as mutually orthogonal scanning magnets) to output the corresponding control magnetic field.

[0069] The method provided in this invention decomposes the complex scanning process into a linear superposition process of sinusoidal wave components in various directions, constructs an easily implemented coordinate relationship, and enables the theoretical multi-order ring scanning mechanism to be converted into control instructions executable by the underlying hardware, laying a solid control model foundation for achieving high beam homogenization on the target surface.

[0070] Based on any of the above embodiments, the step of linearly superimposing the sinusoidal components corresponding to the multi-order scanning waveforms to obtain the coordinate relationship of the beam spot center position on the target surface as a function of time includes: The horizontal position coordinate variation formula is obtained by summing the product of the scanning amplitude of each scanning waveform and the cosine function of the corresponding scanning angular frequency. The vertical position coordinate variation formula is obtained by summing the product of the scanning amplitude of each scanning waveform and the sine function of the corresponding scanning angular frequency. By combining the horizontal position coordinate transformation formula and the vertical position coordinate transformation formula, the two-dimensional coordinate relationship formula is obtained; The target scanning parameters include the scanning angular frequency and scanning amplitude of each order of scanning waveform.

[0071] Specifically, to obtain a coordinate relationship that can be practically applied, the product of the scanning amplitude of each order of scanning waveform and the cosine function of the corresponding scanning angular frequency is first summed to obtain the horizontal position coordinate variation formula. That is, in the horizontal direction (usually set as the X-axis), the change in the beam spot position is driven by the superposition of the cosine components of each order of sine waves.

[0072] Next, the product of the scanning amplitude of each scanning waveform and the sine function of the corresponding scanning angular frequency is summed to obtain the vertical position coordinate change formula. That is, in the vertical direction (usually set as the Y-axis), the change of the set position is driven by the superposition of the sinusoidal components of each order of sine wave, thereby forming a 90° phase difference with the horizontal direction, ensuring that the independent synthetic trajectory of each order is circular.

[0073] Finally, by combining the horizontal and vertical coordinate transformation formulas, we obtain the coordinate relationship. This coordinate relationship can be specifically expressed as follows: in, For the first First scan angular frequency, for Step scan amplitude, and The position of the beam spot center on the target surface over time The changes are significant. Furthermore, the scan order is primarily determined by the upper limit of the peak flux density.

[0074] In this embodiment of the invention, the target scanning parameters include the scanning angular frequency and scanning amplitude of each scanning waveform. The scanning angular frequency determines how quickly the waveform completes one corresponding circular scan; the scanning amplitude determines the basic control radius of the waveform at the target surface.

[0075] The method provided in this invention utilizes explicit formulas for the summation of trigonometric functions to characterize coordinate changes in the horizontal and vertical directions, achieving a complex composite motion where the beam spot center rotates angularly at the target surface while simultaneously undergoing radial modulation. Furthermore, this formulaic model allows the accelerator terminal's scanning control to be accomplished simply by outputting several sets of conventional sinusoidal current waveforms with specific frequencies and amplitudes, effectively avoiding the use of complex spiral-swing scanning mechanisms, thereby reducing the requirements for current power supply technology and hardware implementation costs.

[0076] Based on any of the above embodiments, step S20 specifically includes: Step S21: Control the focusing element group, which consists of multiple quadrupole magnets or solenoids, to constrain the envelope of the initial particle beam in the cross-sectional direction, so that the root mean square dimension of the constrained initial particle beam at the target surface is equal to the target beam spot size.

[0077] Specifically, the focusing element assembly is the core hardware in an accelerator system used for beam optics, and it consists of multiple quadrupole magnets or solenoids. Quadrupole magnets can focus in a transverse plane and defocus in an orthogonal plane, while solenoids can provide axisymmetric focusing force. Using multiple such pieces of hardware together can achieve effective focusing of the beam.

[0078] Constraining the initial particle beam envelope in the cross-sectional direction involves adjusting the excitation current of these magnetic elements to change the magnetic field gradient, thereby spatially compressing the outer boundary (i.e., the envelope) of the beam. During this process, the system also fully considers changes in the beam phase space, enabling the focusing element group to also possess phase shift constraint capabilities between specific points. Through this precise magnetic field constraint, the originally divergent high-power particle beam is focused into a smaller beam spot at the target surface, ensuring that the transverse root-mean-square size (RMS size, usually denoted by σ) of this beam spot is exactly equal to the target beam spot size. For example, if the target beam spot size σ obtained from the previous optimization algorithm is 6 mm, the system will adjust the parameters of the quadrupole magnet to shrink the beam envelope, ensuring that it exhibits a Gaussian distribution with σ = 6 mm when accurately hitting the target surface.

[0079] The embodiments of the present invention employ a focusing element group composed of multiple quadrupole magnets or solenoids, and fully consider the phase space variation to constrain the transverse envelope of the beam, so that the large and divergent initial beam is reshaped into a particle beam that conforms to the target size, providing the optimal input beam for subsequent multi-order sinusoidal wave scanning, thereby maximizing the uniformity of beam coating in the circular area of ​​the target surface.

[0080] Based on any of the above embodiments, after step S21, the method further includes: When there is a specific incident direction requirement for the beam, the initial particle beam is deflected by a diode magnet to change the incident direction of the initial particle beam and enable the initial particle beam to hit the target.

[0081] Specifically, in actual accelerator engineering environments, due to site limitations or the need for multiplexing multiple terminals, the target surface is often not located on the extension line of the accelerator's straight lead-out section. In this case, the system requires a specific incident direction for the beam. In this embodiment of the invention, a dipole magnet, as a magnetic element capable of generating a uniform magnetic field and primarily used to change the trajectory direction of charged particles, is introduced into the control process.

[0082] After completing the lateral constraint of the beam envelope, the system calculates and sends deflection parameters based on the actual position of the terminal, controlling the diode magnet to deflect the constrained particle beam. This deflection changes the incident direction of the particle beam, causing the originally straight-line propagating particle beam to bend according to the preset required direction, ultimately accurately hitting the target surface. It should be understood that this deflection process, along with beam focusing and subsequent lateral scanning, complements each other, together constituting the complete trajectory control of the beam from extraction to target impact.

[0083] The method provided in this invention introduces a diode magnet to deflect the beam direction after focusing constraint, making the homogenization control method applicable not only to linear target shooting scenarios, but also to accelerator terminal environments with specific incident angle requirements or complex spatial layouts, thereby expanding the scope of application of the technical solution of this invention.

[0084] Based on any of the above embodiments Figure 2 This is the second flowchart illustrating the beam homogenization control method within a circular region provided by the present invention, as shown below. Figure 2 As shown, the method includes the following steps: Step S1: Determine the initial beam parameters and terminal constraints.

[0085] Specifically, taking a high-current terminal of a particular accelerator as an example, assuming a proton beam energy of 500 MeV, a continuous wave beam current of 5 mA, and a circular target diameter D = 250 mm, the target constraint condition obtained to ensure equipment safety is: the peak beam current density at the target surface after scanning should not exceed 35 μA / cm². 2 Furthermore, the power loss of the external beam outside the Φ250 is no higher than 10W. The beam spot distribution after scanning meets the following constraints. Considering the beam corona growth caused by accelerator system errors and the high beam energy and power, a corona adjustment factor N=8 is chosen. In this case, without scanning, and solely using the divergent beam for target hitting, the maximum permissible theoretical initial beam size is σ. 大 =D / 2 / N=15.625 mm.

[0086] Figure 3 This is a radial cross-sectional view of the beam spot distribution at the target surface before large beam spot scanning provided by the present invention, as shown in the figure. Figure 3 As shown, even in this extremely divergent large beam pattern, the peak current density at its center is still as high as 325.9493 μA / cm². 2 This far exceeds the target surface's tolerance limit. It should be noted that, as... Figure 3 As shown, the horizontal axis Position (mm) represents the radial position of the beam spot on the target surface, in millimeters (mm); the vertical axis Current density (μA / cm²) represents the radial position of the beam spot on the target surface. 2 The beam density (i.e., the beam intensity per unit area) is expressed in microamperes per square centimeter (μA / cm²). 2 ).

[0087] Step S2: Initial constraint and matching using the focusing element group.

[0088] Specifically, this step does not start the hardware to physically focus the particle beam before parameter optimization, but rather evaluates the focusing capability of the focusing element group and completes the boundary matching of the beam spot size at the control logic and theoretical level.

[0089] To provide a feasible search space for subsequent optimization algorithms, the system needs to comprehensively consider the beam lateral emittance and the limiting focusing capability of the focusing element group, thereby defining the upper and lower limits of the initial beam spot size that can be adjusted. Considering the limitations of beam lateral emittance, focusing capability of the focusing element group, and transient beam peak flux density, the beam spot size σ has a lower limit; considering the target surface size, σ has an upper limit. In this embodiment of the invention, the lower limit of σ is 4 mm, and the upper limit of σ is the σ in step S1. 大 .

[0090] Step S3: Construct a multi-order sine wave superposition ring scanning mechanism.

[0091] Specifically, to effectively flatten the high-density particle beam, a multi-order sinusoidal wave superposition trajectory model was constructed. After preliminary analysis and optimization, it was found that conventional second-order sinusoidal wave superposition scanning could not reduce the peak flux density at the target surface to 35 μA / cm². 2 Therefore, in the following embodiments of the present invention, a more refined third-order sine wave superposition scheme is selected, namely: in, For the first First scan angular frequency, For the first Step scan amplitude, maximum scan radius , and This represents the change in the position of the beam spot center on the target surface over time t. By employing a third-order sine wave superposition scheme, the two-dimensional coordinates of the beam spot center on the target surface can exhibit a complex smearing path over time.

[0092] Step S4: Parameter optimization based on global optimization algorithm.

[0093] Specifically, the physical boundary constraints on the percentage of beam halo power outside the target (i.e. Under the condition of minimizing the peak current density on the target surface, a multi-parameter single-objective global optimization algorithm is used to optimize the scanning parameters. Considering factors such as beam spot size matching and measurement, and scanning magnet technology, the actual parameters are often selected as discrete points. Finally, a set of optimal and discrete optimization parameters was determined: target beam spot size σ = 6 mm, three-order scanning amplitudes R1 = 54.5 mm, R2 = 20 mm, and R3 = 2.5 mm, corresponding to scanning frequencies f1 = 64 Hz, f2 = 59 Hz, and f3 = 49 Hz. .

[0094] Step S5: Apply optimized parameters to perform beam scanning.

[0095] Specifically, the controller sends the aforementioned optimized parameters to the scanning element group to perform high-frequency scanning and target acquisition on the focused small beam spot.

[0096] Figure 4 This is a radial cross-sectional view of the beam spot distribution at the target surface before scanning, provided by the present invention, as shown in the figure. Figure 4 As shown, after the initial particle beam is focused by the focusing element group according to the target beam size in the optimized parameter group, the particle beam is focused into a small beam state. In the transient state before scanning (i.e., before scanning), the beam distribution at the target surface is as follows. Figure 4 As shown, the beam energy is highly concentrated, with the peak current density at its center even rising sharply to 2210.4853 μA / cm². 2 Therefore, this high-density particle beam needs to be guided to the target surface for rapid movement to avoid damage to the target surface caused by excessively high peak flux density.

[0097] Figure 5 This is a three-dimensional image of the beam spot distribution at the target surface of the preferred scanning scheme provided by the present invention. Figure 6 This is a radial cross-sectional view of the beam spot distribution at the target surface of the preferred scanning scheme provided by the present invention, as shown in the figure. Figure 5 and Figure 6 As shown, based on the target scanning parameters in the optimized parameter set, the scanning element group is controlled to perform a lateral scan of the focused particle beam according to a third-order sinusoidal wave superposition trajectory model. The final physical effect formed at the target surface is as follows: Figure 5 and Figure 6 As shown. From Figure 5It can be seen that the spot pattern was smeared into a flat and evenly distributed shape, the void in the center of the spot was effectively filled, and the boundary showed a good circular shape; from Figure 6 As can be seen from the distribution curve, after optimized scanning, the peak beam current density was successfully reduced to 32.1188 μA / cm². 2 It should be noted that, Figure 5 In the diagram, the x-axis represents the horizontal coordinate position on the target surface (in mm), the y-axis represents the vertical coordinate position on the target surface (in mm), and the z-axis represents the beam intensity density at the corresponding (x, y) position.

[0098] The beam homogenization control system within a circular region provided by the present invention is described below. The beam homogenization control system within a circular region described below can be referred to in correspondence with the beam homogenization control method within a circular region described above.

[0099] Based on any of the above embodiments Figure 7 This is a schematic diagram of the beam homogenization control system within a circular region provided by the present invention, as shown below. Figure 7 As shown, the system includes: The focusing element group 710 is configured to laterally focus the initial particle beam; The scanning element group 720, located downstream of the focusing element group 710, is configured to perform a lateral scan of the focused particle beam. The controller 730 is communicatively connected to the focusing element group 710 and the scanning element group 720, respectively, and is used to execute the beam homogenization control method in the circular region as described in any of the above embodiments.

[0100] Specifically, the system provided in this embodiment of the invention mainly includes three core components. The first component is a focusing element group, which is configured to laterally focus the initial particle beam. In the physical layout of the accelerator, this focusing element group is usually located upstream of the beam exit end and is generally composed of multiple quadrupole magnets or solenoids. Its core function is to pre-generate a specific confinement magnetic field before the beam performs the scanning action, constraining the envelope of the initial particle beam in the cross-sectional direction, ensuring that the beam can be reduced to the target beam spot size when it reaches the target surface.

[0101] The second component is a scanning element group, located downstream of the focusing element group, configured to perform lateral scanning of the focused particle beam. Here, the scanning element group typically refers to multiple groups (the number of groups is determined by the scanning order; in this embodiment, there are three groups) of scanning magnets with two mutually orthogonal scanning directions. This element group receives the focused particle beam and is controlled to generate a high-frequency alternating magnetic field that varies according to a multi-order sinusoidal wave superposition trajectory, thereby driving the beam to deflect laterally and spreading a smaller beam spot onto the target surface.

[0102] The third component is a controller, which is communicatively connected to both the focusing element group and the scanning element group. It executes the beam homogenization control method within the circular region as described in any of the above embodiments. This controller can be a specially configured industrial computer, a microprocessor, or a control module integrated into the overall accelerator control system. Through its internally running algorithm, the controller can perform global parameter optimization by comprehensively considering constraints such as target size, peak flux density upper limit, and external beam loss. It then converts the calculated optimal focusing parameters and multi-order sinusoidal scanning parameters into control commands, which are issued to the two groups of physical elements to direct their coordinated operation.

[0103] The system provided in this embodiment of the invention integrates a focusing element group for constraining the envelope, a scanning element group for dynamic coating, and a controller equipped with a multi-order sine wave superposition optimization algorithm to construct a hardware and software collaborative control system architecture. This automatically achieves uniform beam distribution within a circular region, reduces the local thermal load on the target surface, and thus improves the service life of the terminal equipment.

[0104] Figure 8 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 8 As shown, the electronic device may include: a processor 810, a communication interface 820, a memory 830, and a communication bus 840, wherein the processor 810, the communication interface 820, and the memory 830 communicate with each other through the communication bus 840. The processor 810 can call logic instructions in the memory 830 to execute a beam homogenization control method within a circular region. This method includes: acquiring the target beam spot size and target scanning parameters of a multi-order sine wave superposition trajectory model, wherein the multi-order sine wave superposition trajectory model is composed of superimposed multi-order scanning waveforms, each order of scanning waveform containing two sets of sine wave components that are orthogonal to each other in the horizontal and vertical directions; controlling the focusing element group to laterally focus the initial particle beam according to the target beam spot size, so that the focused particle beam forms a smaller beam spot at the target surface; and controlling the scanning element group to laterally scan the focused particle beam according to the multi-order sine wave superposition trajectory model according to the target scanning parameters, so that the particle beam forms a circular distribution at the target surface.

[0105] Furthermore, the logical instructions in the aforementioned memory 830 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to related technologies, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0106] On the other hand, the present invention also provides a computer program product, which includes a computer program that can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the beam homogenization control method within a circular region provided by the above methods. The method includes: acquiring the target beam spot size and target scanning parameters of a multi-order sine wave superposition trajectory model, wherein the multi-order sine wave superposition trajectory model is composed of superimposed multi-order scanning waveforms, and each order scanning waveform contains two sets of sine wave components that are orthogonal to each other in the horizontal and vertical directions; controlling the focusing element group to laterally focus the initial particle beam according to the target beam spot size, so that the focused particle beam forms a smaller beam spot at the target surface; and controlling the scanning element group to laterally scan the focused particle beam according to the multi-order sine wave superposition trajectory model according to the target scanning parameters, so that the particle beam forms a circular distribution at the target surface.

[0107] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements a beam homogenization control method within a circular region provided by the methods described above. The method includes: acquiring a target beam spot size and target scanning parameters of a multi-order sinusoidal wave superposition trajectory model, wherein the multi-order sinusoidal wave superposition trajectory model is composed of superimposed multi-order scanning waveforms, each order of scanning waveform containing two sets of sinusoidal wave components that are orthogonal to each other in the horizontal and vertical directions; controlling a focusing element group to laterally focus an initial particle beam according to the target beam spot size, so that the focused particle beam forms a smaller beam spot at the target surface; and controlling a scanning element group to laterally scan the focused particle beam according to the multi-order sinusoidal wave superposition trajectory model according to the target scanning parameters, so that the particle beam forms a circular distribution at the target surface.

[0108] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0109] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of software products. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the homogenization of a beam in a circular area, characterized in that, include: Obtain the target beam size and target scanning parameters of the multi-order sinusoidal wave superposition trajectory model, wherein the multi-order sinusoidal wave superposition trajectory model is composed of the superposition of multi-order scanning waveforms, and each order of scanning waveform contains two sets of sinusoidal wave components that are orthogonal to each other in the horizontal and vertical directions; Based on the target beam size, the focusing element group is controlled to laterally focus the initial particle beam, so that the focused particle beam forms a smaller beam spot at the target surface. According to the target scanning parameters, the scanning element group is controlled to perform a lateral scan on the focused particle beam according to the multi-order sine wave superposition trajectory model, so that the particle beam forms a circular distribution on the target surface.

2. The control method of beam homogenization in a circular area according to claim 1, wherein, The acquisition of the target beam size and the target scanning parameters of the multi-order sinusoidal wave superposition trajectory model includes: Obtain the target surface constraints; Under the constraints of the target surface, the initial beam spot size and the initial scanning parameters of the multi-order sinusoidal wave superposition trajectory model are optimized to obtain the target beam spot size and the target scanning parameters.

3. The control method of claim 2, wherein The target surface constraints include target surface size, upper limit of peak current density at the target surface, and external beam loss constraints. Under the constraints of these target surface constraints, the initial beam spot size and the initial scanning parameters of the multi-order sinusoidal wave superposition trajectory model are optimized to obtain the target beam spot size and the target scanning parameters, including: Establish the beam halo distribution boundary constraint relationship between the initial beam spot size and the maximum scanning radius, and determine the beam halo distribution boundary constraint relationship as the target external beam loss constraint condition; Using the peak beam current density at the target surface as the optimization objective, and under the constraints of the beam loss outside the target and the upper limit of the peak beam current density at the target surface, a global optimization algorithm is used to optimize the initial beam spot size and the initial scanning parameters to obtain the target beam spot size and the target scanning parameters.

4. The control method of beam homogenization in a circular area according to claim 3, wherein, The establishment of the beam halo distribution boundary constraint relationship between the initial beam spot size and the maximum scanning radius includes: The halo adjustment coefficient is determined based on the proportion of particle power outside the target surface, the beam energy, and the accelerator error. Based on the initial beam spot size, the target surface size, the maximum scanning radius, and the beam halo adjustment coefficient, the beam halo distribution boundary constraint relationship is constructed. The constructed beam halo distribution boundary constraint relationship is as follows: the sum of the products of the maximum scanning radius, the beam halo adjustment coefficient, and the initial beam spot size is less than or equal to the target surface size.

5. The control method of beam homogenization in a circular area according to claim 1, wherein, The steps for constructing the multi-order sinusoidal wave superposition trajectory model include: The sinusoidal components corresponding to the multi-order scanning waveforms are linearly superimposed to obtain the coordinate relationship of the position of the beam spot center on the target surface as a function of time. Based on the coordinate relationship, the multi-order sinusoidal wave superposition trajectory model is obtained.

6. The control method of claim 5, wherein The step of linearly superimposing the sinusoidal components corresponding to the multi-order scanning waveforms to obtain the coordinate relationship of the beam spot center position on the target surface as a function of time includes: The horizontal position coordinate variation formula is obtained by summing the product of the scanning amplitude of each scanning waveform and the cosine function of the corresponding scanning angular frequency. The vertical position coordinate change formula is obtained by summing the product of the scanning amplitude of each order scanning waveform and the sine function of the corresponding scanning angular frequency; The horizontal position coordinate change formula and the vertical position coordinate change formula are combined to obtain the two-dimensional coordinate relationship formula; The target scanning parameters include the scanning angular frequency and the scanning amplitude of each order scanning waveform.

7. The control method of beam homogenization in a circular area according to any one of claims 1 to 6, characterized in that, The control of the focusing element group on the initial particle beam includes: The focusing element group composed of multiple quadrupole magnets or solenoids is controlled to confine the envelope of the initial particle beam in the transverse direction, so that the transverse root mean square size of the confined initial particle beam at the target surface is equal to the target beam spot size.

8. The control method of claim 7, wherein After the step of controlling the focusing element group composed of multiple quadrupole magnets or solenoids to confine the envelope of the initial particle beam in the transverse direction, it further includes: In the case of having specific incident direction requirements for the beam, the dipole magnet is controlled to deflect the confined initial particle beam to change the incident direction of the initial particle beam and make the initial particle beam hit the target.

9. A beam homogenization control system within a circular area, characterized by, It includes: A focusing element group configured to perform transverse focusing on an initial particle beam; A scanning element group arranged downstream of the focusing element group and configured to perform transverse scanning on the focused particle beam; A controller in communication connection with the focusing element group and the scanning element group, respectively, the controller being used to execute the beam homogenization control method in a circular region as claimed in any one of claims 1 to 8.

10. An electronic device comprising a memory, a processor, and a computer program stored on the memory and running on the processor, characterized in that, The processor executes the computer program to realize the beam homogenization control method in a circular region as claimed in any one of claims 1 to 8.

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