Based on H2 + High-current superconducting proton cyclotron beam extraction method and target stripping

Abstract

This invention provides an H2-based + A method for extracting the beam from a high-current superconducting proton cyclotron accelerator and a stripping target are described. The method includes: obtaining K stripping point locations containing multiple energies in the radial and angular directions of the stripping target; and employing a particle tracking program to analyze the H2 at the K stripping point locations. + Two-dimensional scanning of two parameters—energy and peel film azimuth angle—is used to obtain m target peeling points. The positions of these m target peeling points are used as the positions of the target peeling target. This peeling target has two working positions symmetrically positioned on both sides of the valley centerline. The target head of the peeling target is offset from the target rod by a set angle as needed. This invention utilizes H2... + Two-dimensional parameter scanning was performed on two parameters: energy and the azimuth angle of the stripping membrane. Based on the screening of suitable stripping points, extraction trajectories for high-current proton beams with different energies were designed to facilitate the stripping of H2. + The generated high-current proton beam rotates out of the magnetic pole region and reaches the designated position within a finite time step, without hitting the central region and the high-frequency cavity.

Description

Technical Field

[0001] This invention belongs to the field of cyclotron technology, and specifically relates to a method based on H2. + A method for extracting beams from a high-current superconducting proton cyclotron accelerator and for stripping the target. Background Technology

[0002] Variable energy cyclotrons can provide beams of different energy ranges to meet the needs of end users. They are key scientific instruments and indispensable experimental platforms for carrying out nuclear equipment development, cutting-edge research in nuclear science and life sciences, and innovative applications of nuclear technology. They play a vital role in promoting the development of modern nuclear science.

[0003] Currently, the vast majority of commercially available cyclotrons are proton cyclotrons, most of which cannot achieve continuous adjustment of the extracted energy and require the use of de-energizers or range shifters at the terminal to change the energy of the particles.

[0004] To achieve the technical feature of variable energy, most room-temperature accelerators use negative hydrogen for acceleration. A carbon film is placed at the extraction point to strip out protons. In a negative hydrogen cyclotron accelerator, negative hydrogen becomes protons after passing through the stripping film. The protons have opposite charges to the negative hydrogen and are deflected directly outward. Therefore, stripping out negative hydrogen or stripping out with variable energy is relatively easy. However, negative hydrogen exhibits a significant Lorentz stripping phenomenon in a magnetic field. Therefore, the magnetic field in the accelerator cannot exceed 1.5T, otherwise it will cause severe beam loss. Thus, negative hydrogen is difficult to accelerate in a superconducting cyclotron accelerator.

[0005] Compared to negative hydrogen, H2 + The Lorentz stripping phenomenon is not significant during acceleration, allowing for acceleration within a superconducting cyclotron. Furthermore, stripping generates two protons, which is highly advantageous for producing high-current beams. However, the protons generated after stripping react with H2... + Carrying the same type of charge, and the charge-to-mass ratio of the protons is approximately H2. + The charge-to-mass ratio is twice that of the proton, therefore the proton's trajectory deflects inward, and the trajectory radius is approximately H2. + Half of the protons may hit the central region directly, or the high-frequency cavities on both sides, or they may rotate in the magnetic pole region due to their small trajectory radius, making them difficult to extract. Summary of the Invention

[0006] This invention addresses the problems existing in the prior art by proposing a method based on H2. + A method for extracting the beam from a high-current superconducting proton cyclotron accelerator and the method for target stripping. The aim is to solve the problem of H2... + After being stripped, the proton's trajectory deflects inward, with a trajectory radius of approximately H2. +Half of the protons may hit the central region directly, or the high-frequency cavities on both sides, or they may rotate in the magnetic pole region due to their small trajectory radius, making it difficult to extract them.

[0007] To solve its technical problems, the present invention proposes the following technical solutions:

[0008] A H2-based + A method for extracting beams from a high-current superconducting proton cyclotron accelerator, characterized by the following steps:

[0009] Step 1: Obtain the K stripping point positions of the stripping target in the radial and angular directions, encompassing multiple energies; the stripping target is a stripping target with two working positions within the same valley region of the high-current superconducting proton cyclotron accelerator; the K stripping points are the total number of stripping points of the stripping target in the two working positions; the K stripping points of multiple energies are the stripping points on different energy trajectories; particles with higher energy have relatively larger trajectory radii, and particles with lower energy have relatively smaller trajectory radii;

[0010] Step 2: Use a particle tracking program to analyze the H2 values ​​at the K peeling points. + Two-dimensional scanning was performed using two parameters: energy and the azimuth angle of the stripping membrane. The target particle trajectory was determined as follows: the stripped particle trajectory could not enter the central region, nor could it enter the high-frequency region, and it could enter the extraction region. The stripping points that met the target particle trajectory were selected as n candidate stripping points, and m target stripping points were determined from the n candidate stripping points. These m target stripping points are the stripping points that can enter the central region of the extraction region entrance.

[0011] Step 3: Use the positions of m target peeling points as the positions of the target peeling target; the positions of the target peeling target include the radial position and the angular position of the target;

[0012] Step 4: Calculate the physical parameters of the trajectory of m target stripping points focused on the center point of the focusing element's outlet.

[0013] Furthermore, step two, determining m target stripping points from n candidate stripping points, specifically involves:

[0014] 1) Deploy focusing elements in the extraction area. The position of the focusing elements is the location through which the trajectories of the m target stripping points will pass.

[0015] 2) Select m target stripping points from n candidate stripping points whose location is as close as possible to the center point region of the focusing element’s inlet and whose velocity direction is as close as possible to the axis of symmetry of the focusing element;

[0016] 3) The positions of m target stripping points are used as the positions of the target stripping target.

[0017] Furthermore, step four, calculating the physical parameters of the trajectory of the m target stripping points focused on the center point of the focusing element's exit, specifically involves:

[0018] 1) Calculate the velocity direction of m target stripping point particles in the center point region of the focusing element entrance: Calculate the velocity direction of m target stripping point particles before they enter the focusing element, based on the edge field of the main magnet, so that the direction of the particle velocity is approximately perpendicular to the edge line of the center point region of the focusing element entrance;

[0019] 2) Calculate the velocity direction of m target stripping point particles at the center point of the focusing element exit: superimpose the magnetic field of the focusing element on the edge field of the main magnet, calculate the velocity direction of m target stripping point particles after entering the focusing element under the superposition of the two magnetic fields, adjust the magnetic field of the focusing element according to the velocity direction, so that particles of different energies are focused at the center point of the focusing element exit, and the particle velocity direction at the center point of the focusing element exit is the same as the direction of the symmetry axis of the focusing element.

[0020] 3) Save the adjusted focusing element magnetic field;

[0021] 4) Determine the physical design of the focusing element based on the adjusted magnetic field of the focusing element;

[0022] Furthermore, the center point region of process 2) in step two refers to the inlet center point region where the trajectories of the m target stripping points can be focused at the outlet center point of the focusing element after the magnetic field of the focusing element and the main magnetic field are superimposed.

[0023] A dual-working-position stripping target is characterized in that: a stripping target has two working positions in the same valley area, and the two working positions are symmetrical on both sides of the center line of the valley area.

[0024] A dual-working-position stripping target, characterized in that: the symmetry along the center line of the valley area means that the position of the stripping target at the symmetrical point must satisfy the following conditions: the trajectory of the stripped particle cannot enter the central area, the trajectory of the stripped particle cannot enter the high-frequency area, and the trajectory of the stripped particle can enter the extraction area.

[0025] A dual-working-position stripping target, characterized in that: the m target stripping points are the sum of stripping points that meet certain conditions at the two working positions of the stripping target, namely: the stripped particle trajectory cannot enter the central region, the stripped particle trajectory cannot enter the high-frequency region, and the stripped particle trajectory can enter the extraction region.

[0026] Furthermore, the target head of the peeling target is offset from the target rod by a set angle as needed.

[0027] Furthermore, the set angle refers to the angle formed by the line connecting the peeling point and the tail of the target rod and the target rod when one of the m peeling points is not on the straight line of the target rod.

[0028] Advantages and effects of the present invention

[0029] The effective benefit of this invention is: through the control of H2 + Two-dimensional parameter scanning was performed on two parameters: energy and the azimuth angle of the stripping membrane. Based on the screening of suitable stripping points, extraction trajectories for high-current proton beams with different energies were designed to facilitate the stripping of H2. + The generated high-current proton beam, without hitting the central region or the high-frequency cavity, rotates out of the magnetic pole region and reaches the designated position within a finite time step. Based on this, the mechanical design of the stripping target device and the design of the extraction and focusing elements were also carried out. Through parameter scanning to select the trajectory and the design of the stripping target device and the extraction and focusing elements, the extraction of a variable-energy high-current proton beam from a superconducting cyclotron was achieved, overcoming the limitations imposed by the Lorentz stripping phenomenon on the extraction of variable-energy proton beams from negative hydrogen in superconducting cyclotrons, as well as the stripping of H2. + The resulting proton beam trajectory is difficult to plan. (H2 stripping) + The derived variable-energy high-current proton beam can be used for bombarding lithium and beryllium targets, proton therapy, and simulation of single-event effects in deep space radiation environments, and has broad application prospects. Attached Figure Description

[0030] Figure 1 This is a schematic diagram illustrating the screening of m target stripping points according to the present invention;

[0031] Figure 2 This is a schematic diagram of a peeling target having two working positions according to the present invention;

[0032] Figure 3 This invention provides a method and flowchart for extracting beams from a high-current superconducting proton cyclotron accelerator based on H2+. Detailed Implementation

[0033] Design principle of this invention:

[0034] 1. Innovation of this invention: The innovation lies in finding a beam extraction method for high-current superconducting cyclotron accelerators. This method involves extracting the beam from H2. + A method for stripping and extracting protons is proposed. Most conventional accelerators use negative hydrogen for acceleration, placing a carbon film at the extraction point to strip and extract protons. However, negative hydrogen is difficult to accelerate in superconducting cyclotron accelerators. This invention uses H2. + Acceleration, compared to negative hydrogen, has the following advantages: First, H2 + First, the Lorentz stripping phenomenon during acceleration is not significant. Second, it can be accelerated in a superconducting cyclotron. Third, unlike acceleration using negative hydrogen, H2...+ Two protons can be generated through stripping, which is highly advantageous for generating high-current beams; this invention uses H2. + Acceleration, compared to negative hydrogen, has the following disadvantages: H2 + The mass number of protons produced after stripping is H2. + The mass of a proton is half that of a carbon atom and also carries one positive charge; therefore, the charge-to-mass ratio of a proton is approximately H2. + The charge-to-mass ratio is twice that of the proton, therefore the proton's trajectory deflects inward, and the trajectory radius is approximately H2. + Half of it, because the proton's trajectory is deflected inwards, and the trajectory radius is approximately H2. + Half of the protons might hit the central region directly, or the high-frequency cavities on either side, or they might remain rotating in the magnetic pole region due to their small trajectory radius, making them difficult to extract. The innovation lies in: fully utilizing H2 + It offers the advantages of stripping and extraction while overcoming the limitations of using H2. + Due to the disadvantages of stripping and extraction, a beam extraction method for high-current superconducting cyclotron accelerators was found.

[0035] 2. Solution of the present invention: The present invention overcomes the limitations of using H2 + The specific steps for stripping away the disadvantages can be summarized as follows: A) First, identify m target stripping points that meet the criteria; B) Then, determine the location of the stripping target based on the m target stripping points. The difference from traditional methods is that the locations of the stripping points in traditional methods are known in advance and are therefore fixed. Generally, the stripping points are placed on the outermost beam trajectory of the accelerator because the outermost beam trajectory has the highest energy. In this invention, the locations of the stripping points are selected from tens of thousands of stripping points. Which of the m target stripping points should be is unknown in advance; it is only known after screening, and the screening process involves two rounds: the first round selects n candidate stripping points from K candidate stripping points, and the second round selects m target stripping points from the n candidate stripping points.

[0036] 1) First, find m target stripping points that meet the following conditions: The m target stripping points meet the following conditions: First, they contain multiple energies; second, the stripped particle trajectory cannot enter the central region, nor can it enter the high-frequency region, but it can enter the extraction region; third, they can enter the central area of ​​the extraction region's entrance. The specific steps are: ① First, determine K stripping points containing multiple energies, each energy representing a particle trajectory. Higher energy particle trajectories have relatively larger radii, and lower energy particle trajectories have relatively smaller radii; ② From the K stripping points, select n candidate stripping points that meet the following conditions: the stripped particle trajectory cannot enter the central region, nor can it enter the high-frequency region, and it can enter the extraction region. Use the stripping points that meet the target particle trajectory as n candidate stripping points; ③ From the n candidate stripping points, select m target stripping points that can enter the central area of ​​the extraction region's entrance.

[0037] 2) Then determine the position of the peeling target based on the m target peeling points.

[0038] The difference from traditional methods is that traditional methods use two peeling targets arranged symmetrically at 180 degrees, while this invention uses only one peeling target with two working positions, both located within the same valley area. The peeling targets at each working position are angled to each other along a straight line. The reason for having two working positions for one peeling target is to acquire as many target peeling points as possible (m). This is because the peeling angle of the peeling target at each working position is finite. The finite peeling angle refers to the finite deflection angle of the target head. Since the target rod can only move back and forth along a straight line, when a peeling point among the m peeling points is not on the same straight line as the current target rod, simply moving the target rod back and forth is insufficient for peeling. The target head must be modified, changing it from being on the same straight line to having the target head deviate from the target rod at an angle. This angle is also finite, so when the peeling range of one peeling target is limited, two peeling targets are used.

[0039] Based on the above principles, this invention designs a method based on H2. + Methods for extracting beams from high-current superconducting proton cyclotron accelerators, such as Figure 1 , Figure 2 , Figure 3 As shown, its characteristics include the following steps:

[0040] Step 1: Obtain the K stripping point positions of the stripping target in the radial and angular directions, encompassing multiple energies; the stripping target is a stripping target with two working positions within the same valley region of the high-current superconducting proton cyclotron accelerator; the K stripping points are the total number of stripping points of the stripping target in the two working positions; the K stripping points of multiple energies are the stripping points on different energy trajectories; particles with higher energy have relatively larger trajectory radii, and particles with lower energy have relatively smaller trajectory radii;

[0041] Step 2: Use a particle tracking program to analyze the H2 values ​​at the K peeling points. + Two-dimensional scanning was performed using two parameters: energy and the azimuth angle of the stripping membrane. The target particle trajectory was determined as follows: the stripped particle trajectory could not enter the central region, nor could it enter the high-frequency region, and it could enter the extraction region. The stripping points that met the target particle trajectory were selected as n candidate stripping points, and m target stripping points were determined from the n candidate stripping points. These m target stripping points are the stripping points that can enter the central region of the extraction region entrance.

[0042] Supplementary Note 1

[0043] like Figure 1 As shown, a total of m target stripping points were selected, one above and one below. The stripping point located higher in the relative position rotates twice and is led out, while the stripping point located lower in the relative position rotates once and is led out. Neither of their trajectories enters the central region nor the high-frequency cavity. At the same time, both trajectories are within the central region of the switch magnet inlet, and their exits converge at the center point of the switch magnet outlet.

[0044] Step 3: Use the positions of m target peeling points as the positions of the target peeling target; the positions of the target peeling target include the radial position and the angular position of the target;

[0045] Step 4: Calculate the physical parameters of the trajectory of m target stripping points focused on the center point of the focusing element's outlet.

[0046] Furthermore, step two, determining m target stripping points from n candidate stripping points, specifically involves:

[0047] 1) Deploy focusing elements in the extraction area. The position of the focusing elements is the location through which the trajectories of the m target stripping points will pass.

[0048] 2) Select m target stripping points from n candidate stripping points whose location is as close as possible to the center point region of the focusing element’s inlet and whose velocity direction is as close as possible to the axis of symmetry of the focusing element;

[0049] 3) The positions of m target stripping points are used as the positions of the target stripping target.

[0050] Furthermore, the calculation of the physical parameters of the trajectory of the m target stripping points in step four, which is focused on the center point of the focusing element's exit, is specifically as follows:

[0051] 1) Calculate the velocity direction of m target stripping point particles in the center point region of the focusing element entrance: Calculate the velocity direction of m target stripping point particles before they enter the focusing element, based on the edge field of the main magnet, so that the direction of the particle velocity is approximately perpendicular to the edge line of the center point region of the focusing element entrance;

[0052] 2) Calculate the velocity direction of m target stripping point particles at the center point of the focusing element exit: superimpose the magnetic field of the focusing element on the edge field of the main magnet, calculate the velocity direction of m target stripping point particles after entering the focusing element under the superposition of the two magnetic fields, adjust the magnetic field of the focusing element according to the velocity direction, so that particles of different energies are focused at the center point of the focusing element exit, and the particle velocity direction at the center point of the focusing element exit is the same as the direction of the symmetry axis of the focusing element.

[0053] 3) Save the adjusted focusing element magnetic field;

[0054] 4) Determine the physical design of the focusing element based on the adjusted magnetic field of the focusing element;

[0055] Furthermore, the center point region of process 2) in step two refers to the inlet center point region where the trajectories of the m target stripping points can be focused at the outlet center point of the focusing element after the magnetic field of the focusing element and the main magnetic field are superimposed.

[0056] A dual-working-position stripping target is characterized in that: a stripping target has two working positions in the same valley area, and the two working positions are symmetrical on both sides of the center line of the valley area.

[0057] Furthermore, the symmetry along the center line of the valley area means that the peeling target position at the symmetry point must satisfy the following conditions: the peeled particle trajectory cannot enter the central area, the peeled particle trajectory cannot enter the high-frequency area, and the peeled particle trajectory can enter the extraction area.

[0058] Furthermore, the m target stripping points are the sum of the stripping points that meet the conditions at the working positions of the two stripping targets. The conditions are: the stripped particle trajectory cannot enter the central region, the stripped particle trajectory cannot enter the high-frequency region, and the stripped particle trajectory can enter the extraction region.

[0059] Furthermore, the target head of the peeling target is offset from the target rod by a set angle as needed.

[0060] Supplementary Note 2

[0061] like Figure 2As shown, the target head of the peeling target is offset from the target rod by a set angle as needed. When the peeling point and the target rod are on the same straight line, the target head and the target rod are parallel at 180 degrees. When the peeling point and the target rod are not on the same straight line, the target head is offset from the target rod by an angle.

[0062] Furthermore, the set angle refers to the angle formed by the line connecting the peeling point and the tail of the target rod and the target rod when one of the m peeling points is not on the straight line of the target rod.

[0063] It should be emphasized that the above specific embodiments are merely explanations of the present invention and are not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to the above embodiments without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method based on H2 + A method for extracting beams from a high-current superconducting proton cyclotron accelerator, characterized in that... Includes the following steps: Step 1: Obtain the locations of K ablation points on the ablation target, each containing multiple energies in the radial and angular directions; The stripping target is a stripping target with two working positions in the same valley region of the high-current superconducting proton cyclotron accelerator; the K stripping points are the total number of stripping points of the stripping target in the two working positions; the K stripping points of multiple energies are the stripping points on different energy trajectories; the particle trajectory radius of the particle with higher energy is relatively large, and the particle trajectory radius of the particle with lower energy is relatively small. Step 2: Use a particle tracking program to analyze the H2 values ​​at the K peeling points. + Two-dimensional scanning was performed using two parameters: energy and the azimuth angle of the stripping membrane. The target particle trajectory was determined as follows: the stripped particle trajectory could not enter the central region, nor could it enter the high-frequency region, and it could enter the extraction region. The stripping points that met the target particle trajectory were selected as n candidate stripping points, and m target stripping points were determined from the n candidate stripping points. These m target stripping points are the stripping points that can enter the central region of the extraction region entrance. Step 3: Use the positions of m target peeling points as the positions of the target peeling target; the positions of the target peeling target include the radial position and the angular position of the target; Step 4: Calculate the physical parameters of the trajectory of m target stripping points focusing on the center point of the focusing element exit.

2. The method based on H2 according to claim 1 + A method for extracting beams from a high-current superconducting proton cyclotron accelerator, characterized in that: Step two, determining m target stripping points from n candidate stripping points, specifically involves: 1) Deploy focusing elements in the extraction area. The position of these focusing elements is the location through which the trajectories of the m target stripping points will pass. 2) Select m target stripping points from n candidate stripping points whose location is as close as possible to the center point region of the focusing element's inlet and whose velocity direction is as close as possible to the symmetry axis direction of the focusing element; 3) The positions of m target stripping points are used as the positions of the target stripping target.

3. The method based on H2 according to claim 1 + A method for extracting beams from a high-current superconducting proton cyclotron accelerator, characterized in that: Step four involves calculating the physical parameters of the trajectory of the m target stripping points focused on the center point of the focusing element's exit point, specifically as follows: 1) Calculate the velocity direction of m target stripping point particles in the center point region of the focusing element entrance: Calculate the velocity direction of m target stripping point particles before they enter the focusing element, based on the edge field of the main magnet, so that the direction of the particle velocity is approximately perpendicular to the edge line of the center point region of the focusing element entrance; 2) Calculate the velocity direction of m target stripping point particles at the center point of the focusing element exit: superimpose the magnetic field of the focusing element on the edge field of the main magnet, calculate the velocity direction of m target stripping point particles after entering the focusing element under the superposition of the two magnetic fields, adjust the magnetic field of the focusing element according to the velocity direction, so that particles of different energies are focused at the center point of the focusing element exit, and the particle velocity direction at the center point of the focusing element exit is the same as the direction of the symmetry axis of the focusing element. 3) Save the adjusted focusing element magnetic field; 4) Determine the physical design of the focusing element based on the adjusted magnetic field of the focusing element.

4. The method based on H2 according to claim 2 + A method for extracting beams from a high-current superconducting proton cyclotron accelerator, characterized in that: The center point region of process 2) in step two refers to the inlet center point region where the trajectories of the m target stripping points can be focused at the center point of the outlet of the focusing element after the magnetic field of the focusing element and the main magnetic field are superimposed.

5. A method for use in any one of claims 1-4 based on H2 + The dual-working-position stripping target of the high-current superconducting proton cyclotron beam extraction method is characterized by: A stripping target has two working positions within the same valley area, and the two working positions are symmetrical about both sides of the center line of the valley area.

6. A dual-working-position stripping target according to claim 5, characterized in that: The symmetry along the center line of the valley area means that the peeling target position at the symmetrical point must satisfy the following conditions: the peeled particle trajectory cannot enter the central area, the peeled particle trajectory cannot enter the high-frequency area, and the peeled particle trajectory can enter the extraction area.

7. A dual-working-position stripping target according to claim 5, characterized in that: The m target stripping points are the sum of the stripping points that meet the conditions at the working positions of the two stripping targets. The conditions are: the stripped particle trajectory cannot enter the central region, the stripped particle trajectory cannot enter the high-frequency region, and the stripped particle trajectory can enter the extraction region.

8. A dual-working-position stripping target according to claim 5, characterized in that: The target head of the peeling target is offset from the target rod by a set angle as needed.

9. A dual-working-position stripping target according to claim 8, characterized in that: The set angle refers to the angle formed by the line connecting the peeling point and the tail of the target rod and the target rod when one of the m peeling points is not on the straight line of the target rod.

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