Proton Synchrotron

Abstract

This disclosure provides a proton synchrotron, comprising: six linear units, each including a dipole, a horizontally focusing quadrupole, a vertically focusing quadrupole, and a linear section. The horizontal and vertical quadrupoles are located on opposite sides of the dipole and connected in series on the linear section. The linear section connects the linear units in pairs, forming a hexagonal ring structure. Horizontal closed-track correction is performed by adjusting the excitation current ratio of the dipoles. Two hexagonal poles are located on two symmetrically arranged linear sections within the hexagonal ring structure. The magnetic induction polarities of the two hexagonal poles are opposite, and they work together to adjust chromaticity and resonance intensity. Four correction poles are symmetrically arranged on the four linear sections of the hexagonal ring structure for vertical closed-track correction. This proton synchrotron has advantages such as fewer components, compact structure, low injection energy, and low manufacturing cost.

Description

Technical Field

[0001] This disclosure relates to the field of proton synchrotron technology, and more particularly to a proton synchrotron. Background Technology

[0002] A synchrotron is a device that injects, accelerates, and extracts a beam of charged particles by controlling the timing structure of the front-end injector, the magnetic field of the synchrotron magnet, the longitudinal high-frequency electric field, and injection elements. It is widely used in fields such as medicine, biology, materials, and physics.

[0003] In accelerators, the value of dividing the transverse motion frequency by the cyclotron frequency is usually called the operating point v. x，y This value is determined by the accelerator design. Due to energy deviation, space charge effects, and other factors, the transverse motion frequency of each individual particle will differ from the operating point. When the operating point satisfies mv x +nv y When l = 1 and the synchrotron magnet contains a higher-order field of the corresponding order, the beam motion will undergo nonlinear resonance, increasing the beam emittance and envelope, and causing beam loss. When the value of l is an integer multiple of the number of periods in the synchrotron substructure, it is called system resonance; otherwise, it is called random resonance. Generally, the operating point should be selected to avoid system resonance. It is easy to see from the conditions for system resonance that the more periods the synchrotron has, the fewer the system resonance lines will be. For example, 2v... x +2v y =6. For a synchrotron loop with 2 periods, it is a system resonance; for a synchrotron loop with 12 periods, it is a random resonance. The study found that the main factor limiting the number of particles that can be stored in a synchrotron is the space charge effect during injection, which causes particles to be lost due to crossing the resonance line.

[0004] To increase the number of particles stored, multi-turn or stripping injection methods are typically used to increase the initial emittance of the beam, while simultaneously increasing the injector energy. Optimizing the synchrotron ring design, such as adjusting the edge angles of the dipoles and quadrupoles within the ring, reduces the effect of space charge forces, preventing space charge effects from causing resonance line crossings. However, in general, existing proton synchrotrons still suffer from drawbacks such as high manufacturing costs, high injection energy requirements, and large and heavy magnets. Summary of the Invention

[0005] In view of the above problems, the present invention provides a proton synchrotron to solve the aforementioned technical problems. One aspect of this disclosure provides a proton synchrotron, comprising: six linear units for causing a proton beam to periodically move and accelerate along a fixed track formed by the linear units to increase energy; each linear unit includes a dipole, a horizontally focusing quadrupole, a vertically focusing quadrupole, and a linear section; the horizontally and vertically focusing quadrupoles are respectively disposed on both sides of the dipole and connected in series on the linear section; the linear section connects the linear units in pairs to form a hexagonal ring structure; wherein horizontal closed-track correction is performed by adjusting the excitation current ratio of the dipoles; two hexagonal poles are respectively disposed on two symmetrically arranged linear sections in the hexagonal ring structure; the two hexagonal poles have opposite polarities, and chromaticity and resonance intensity are independently adjusted by adjusting the ratio of magnetic induction intensity according to a preset rule; and four correction irons are symmetrically disposed on the four linear sections of the hexagonal ring structure for vertical closed-track correction.

[0006] Optionally, it also includes an injection system, wherein the injection method is multi-turn injection, the injection system comprising: an injection cutting magnet disposed on a straight section without the correction iron; an injection electrostatic cutter disposed on the straight section where the injection cutting magnet is located; and a first convex rail magnet, a second convex rail magnet, a third convex rail magnet, and a fourth convex rail magnet disposed sequentially on four adjacent straight sections including the straight section where the injection cutting magnet is located.

[0007] Optionally, the system further includes an extraction system comprising: an extraction cutting magnet disposed on a linear segment opposite to the position of the injection cutting magnet, adjacent to a horizontally focusing quadrupole on the linear segment; an extraction electrostatic cutter disposed on a linear segment adjacent to the linear segment containing the extraction cutting magnet, adjacent to a horizontally focusing quadrupole on the linear segment; a fourth, a fifth, and a sixth convex rail magnet, wherein the sixth convex rail magnet is disposed on a linear segment opposite to the position of the fourth convex rail magnet, and the fifth convex rail magnet is disposed on the linear segment containing the extraction cutting magnet; and a transverse excitation system disposed on any linear segment.

[0008] Optionally, the first, second, third, and fourth convex rail magnets are not located on the same linear joint as the lead-out cutting magnet and the lead-out electrostatic cutter.

[0009] Optionally, the correction iron is located on a straight section other than the straight section where the injection cutting magnet and the lead-out cutting magnet are located.

[0010] Optionally, the phase shift between the electrostatic cutter and the cutting magnet is 90 degrees.

[0011] Optionally, beam acceleration relies on a high-frequency accelerating cavity, which can be installed on any straight section.

[0012] Optionally, the operating point of the proton synchrotron is 1.666 to 1.7, and the phase shift of each linear unit is 100 to 102 degrees.

[0013] Optionally, the length of the diode is 1.5 meters, the envelope function at the diode does not exceed 5 meters, the length of the straight section is 2.8 meters, and the weight of a single magnet in the proton synchrotron is less than 5 tons.

[0014] Optionally, a horizontal position probe is installed inside the horizontally focusing quadrupole, and a vertical position probe is installed inside the vertically focusing quadrupole.

[0015] The above-described at least one technical solution adopted in the embodiments of this disclosure can achieve the following beneficial effects:

[0016] (1) The proton synchrotron provided in this embodiment consists of six identical FODO units. Six horizontally focused quadrupoles and six vertically focused quadrupoles are connected in series for power supply, which saves on power supply costs and facilitates adjustment of the operating point. Synchronous ring closed-track correction is achieved by adjusting the excitation curve of the dipoles. Compared with other schemes, it saves on horizontal correction irons, and the number of vertical correction irons is only four. The synchronous ring's lead-out resonant hexapod and chromaticity correction hexapod are integrated together, and the functions of resonant intensity adjustment and chromaticity correction are achieved using only two dipoles. The injection and lead-out cutting magnets are located on opposite linear sections, the distribution of injection and lead-out elements is more reasonable, the space utilization of the linear sections is high, and the layout is more compact.

[0017] (2) The proton synchrotron provided in this embodiment has a small overall size, and the weight of a single magnet is less than 5t, so the installation of the magnet can be completed without a high-tonnage crane. The total number of cycles is 6, and the phase shift of each cycle is close to 90 degrees, which is physically beneficial for beam extraction and reduces the intensity of the electrostatic cutter;

[0018] (3) The proton synchrotron provided in this embodiment adopts a multi-cycle injection scheme, resulting in a larger injected beam emittance. Simultaneously, the beam envelope function is optimized, with the envelope function at the diode not exceeding 5m, leading to a smaller beam aperture for the same acceptability. The multi-cycle structure, combined with optimized operating point, reduces the number of system resonance lines while keeping the operating point further away from them. An injection energy of only 3 MeV or higher is sufficient to achieve a storage current of 9E10ppp. The injector only requires RFQ instead of the conventional RFQ+DTL scheme, significantly reducing costs. Attached Figure Description

[0019] To gain a more complete understanding of this disclosure and its advantages, reference will now be made to the following description taken in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 The schematic diagram illustrates a proton synchrotron provided in an embodiment of the present disclosure;

[0021] Figure 2 The schematic diagram illustrates a beam envelope function, a beam dispersion function, and a beam envelope diagram of a proton synchrotron provided in an embodiment of the present disclosure.

[0022] Figure 3 This schematic diagram illustrates the operating point of a proton synchrotron provided in an embodiment of the present disclosure.

[0023] Figure 4A The schematic illustration shows the beam frequency distribution of a proton synchrotron provided in an embodiment of the present disclosure when injected at an operating point;

[0024] Figure 4B This schematically illustrates the beam frequency distribution of a proton synchrotron provided in an embodiment of the present disclosure when injected at another operating point;

[0025] Figure 5 The illustration schematically shows the particle survival of a proton synchrotron provided in an embodiment of the present disclosure at different operating points and injected energies.

[0026] Explanation of reference numerals in the attached figures:

[0027] 11-Dipolar magnet; 21-Horizontal focusing quadrupole magnet; 31-Vertical focusing quadrupole magnet; 41-Hexapolar magnet; 51-Correcting magnet; 61-Injection cutting magnet; 62-Injection electrostatic cutter; 71-First convex rail magnet; 72-Second convex rail magnet; 73-Third convex rail magnet; 74-Fourth convex rail magnet; 75-Fifth convex rail magnet; 76-Sixth convex rail magnet; 81-Extraction cutting magnet; 82-Extraction electrostatic cutter; 83-Transverse excitation system; 91-Beam acceleration relies on high-frequency acceleration cavity. Detailed Implementation

[0028] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0029] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0030] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0031] Figure 1 The schematic diagram illustrates a proton synchrotron provided in an embodiment of the present disclosure.

[0032] like Figure 1 As shown, a proton synchrotron provided in this embodiment includes six linear units for causing the proton beam to move periodically along a fixed track formed by the linear units and accelerate to increase energy. Each linear unit includes a dipole 11, a horizontal focusing quadrupole 21, a vertical focusing quadrupole 31, and a straight section. The horizontal focusing quadrupole 21 and the vertical focusing quadrupole 31 are respectively located on both sides of the dipole 11 and connected in series on the straight section. The straight section connects the linear units in pairs to form a hexagonal ring structure. In this embodiment, the dipole 11 is approximately 1.5 meters long, and the envelope function at the dipole 11 does not exceed 5 meters; the straight section is approximately 2.8 meters long; and the weight of a single magnet in the proton synchrotron is less than 5 tons. A horizontal position probe is installed inside the horizontal focusing quadrupole (21), and a vertical position probe is installed inside the vertical focusing quadrupole (21).

[0033] The accelerator also includes two hexapoles 41, symmetrically positioned on two linear nodes within a hexagonal ring structure. The two hexapoles 41 have opposite polarities, and their magnetic induction intensities are configured according to preset criteria. If the intensity of the hexapoles 41 is considered as A+B and -A+B, then the effect of each hexapole 41 in beam physics can be viewed as the superposition of two spatially overlapping hexapoles 41. The value of A only affects the resonant intensity, and the value of B only affects the chromaticity. This method allows for independent adjustment of chromaticity and resonant intensity using only two hexapoles 41.

[0034] Typically, closed-track correction requires the use of correction irons 51, which are essentially low-strength, small-sized dipole irons 11. In this embodiment, the accelerator includes four correction irons 51, symmetrically arranged on the four straight sections of a hexagonal ring structure, for vertical closed-track correction. In this embodiment, to reduce the number of accelerator components and make the synchrotron ring more compact, the vertical correction irons 51 are only installed on the straight sections other than the injection cutting magnet 61 and the extraction cutting magnet 81, and are respectively installed near the four vertical focusing quadrupole irons 31. Furthermore, in the proton synchrotron provided in this embodiment, horizontal closed-track correction can be performed by adjusting the excitation current ratio of the dipole irons 11, saving horizontal correction irons compared to existing accelerators.

[0035] The proton synchrotron provided in this embodiment further includes an injection system, which includes: an injection cutting magnet 61 disposed on a straight section without a correction iron 51; an injection electrostatic cutter 62 disposed on the straight section where the injection cutting magnet 61 is located; and a first convex rail magnet 71, a second convex rail magnet 72, a third convex rail magnet 73, and a fourth convex rail magnet 74 disposed sequentially on four adjacent straight sections including the straight section where the injection cutting magnet 61 is located.

[0036] An embodiment of this disclosure provides a proton synchrotron that further includes an extraction system, comprising: an extraction cutting magnet 81, disposed on a linear segment opposite to the position of the injection cutting magnet 61, adjacent to the horizontal focusing quadrupole 21 on the same linear segment; an extraction electrostatic cutter 82, disposed on a linear segment adjacent to the linear segment containing the extraction cutting magnet 81, adjacent to the horizontal focusing quadrupole 21 on the same linear segment; a fourth convex rail magnet 74, a fifth convex rail magnet 75, and a sixth convex rail magnet 76, wherein the sixth convex rail magnet 76 is disposed on a linear segment opposite to the position of the fourth convex rail magnet 74, and the fifth convex rail magnet 75 is disposed on the linear segment containing the extraction cutting magnet 81; and a transverse excitation system 83, disposed on any linear segment. The first convex rail magnet 71, the second convex rail magnet 72, the third convex rail magnet 73, and the fourth convex rail magnet 74 are not disposed on the same linear segment as the extraction cutting magnet 81 and the extraction electrostatic cutter 82.

[0037] The proton synchrotron provided in this embodiment consists of 6 cycles with an operating point close to 1.666–1.7. The phase shift of each cycle is 100–102 degrees. The extraction cutting magnet 81 and the extraction electrostatic cutter 82 are installed near the horizontal focusing quadrupole 21, where the horizontal envelope function β has a maximum value. The phase shift between the electrostatic cutter and the extraction cutting magnet 81 is 90 degrees, which is beneficial for the design of the extraction track and reduces the strength of the electrostatic cutter.

[0038] In this embodiment, the injection cutting magnet 61 and the extraction cutting magnet 81 are located in opposite linear segments, allowing the injection-related convex rail magnets, electrostatic cutters, etc., to be distributed on different linear segments, effectively utilizing space and shortening the length of the linear segments. If the injection cutting magnet is placed on a linear segment adjacent to the extraction electrostatic cutter 82, similar to the scheme described in patent application number 201210264179.2, then due to the presence of the hexapolar iron 41 on that linear segment, a longer linear segment is required to accommodate it compared to the scheme described in this disclosure. Simultaneously, the convex rail magnet 56 must also be moved accordingly to the linear segment where the extraction electrostatic cutter 82 is located, further increasing the length of that linear segment. Ultimately, the length of the linear segments must be uniformly the longest of all linear segments to ensure the periodicity of the synchrotron. Therefore, the layout scheme of this disclosure is more reasonable.

[0039] The proton synchrotron provided in this embodiment also includes a beam acceleration relying on a high-frequency acceleration cavity 91, which can be installed in any linear section.

[0040] In accelerators, the value of dividing the transverse motion frequency by the cyclotron frequency is usually called the operating point v. x，y This value is determined by the accelerator design. Meanwhile, due to energy deviation, space charge effects, and other factors, the transverse motion frequency of each individual particle will differ from that at the operating point. When the operating point satisfies mv x +nv y When l = 1 and the synchrotron magnet contains a higher-order field of the corresponding order, the beam motion will undergo nonlinear resonance, increasing the beam emittance and envelope, and causing beam loss. When the value of l is an integer multiple of the number of periods in the synchrotron substructure, it is called system resonance; otherwise, it is called random resonance. Generally, the operating point should be selected to avoid system resonance. It is easy to see from the conditions for system resonance that the more periods the synchrotron has, the fewer the system resonance lines will be. For example, 2v... x +2v y =6. For a synchrotron loop with 2 periods, this is system resonance; for a synchrotron loop with 12 periods, it is random resonance. The study found that the main factor limiting the number of particles that can be stored in a synchrotron is the space charge effect during injection, which causes particle loss due to crossing resonance lines. The strength of the space charge effect depends primarily on the injection energy, emittance, and total number of particles.

[0041]

[0042] In the formula, Δν is the frequency shift caused by the space charge effect, and r p Where β is the classical radius, N is the particle number, β and γ correspond to the relativistic factors of the injected energy, and B is the classical radius. f ε is the beam focusing factor, and ε is the beam emittance.

[0043] In this embodiment, to reduce the beam envelope and thus better utilize the lateral acceptability, the proton synchrotron provided in this embodiment reduces the size of the diode 11 and increases the number of stored particles. A quadrupole with greater strength is used to better focus and confine the beam envelope. Since the extremum of the envelope function is typically located at the quadrupole, the quadrupole is installed slightly away from the diode 11. Ultimately, optimization ensures that the envelope function value within the diode does not exceed 5m.

[0044] Figure 2 The diagram illustrates the beam envelope function, dispersion function, and beam envelope schematic of a proton synchrotron provided in an embodiment of the present disclosure.

[0045] like Figure 2 As shown, the proton synchrotron provided in this embodiment of the present disclosure, under the conditions of momentum deviation ±0.005, horizontal acceptability 250πmm·mrad, and vertical acceptability 75πmm·mrad, has a horizontal envelope of the beam within the diode 11 that does not exceed 50mm and a vertical envelope that does not exceed 20mm.

[0046] To reduce the impact of space charge effect on the beam, the proton synchrotron injection scheme provided in this disclosure employs multi-cycle injection. Particles are continuously injected into the synchrotron ring at a relatively low current intensity over approximately 200 cycles, and the injection beam is gradually filled with horizontal acceptors by adjusting four injection convex rail magnets (54, 55, 56, 53), thereby increasing the transverse emittance of the beam.

[0047] To avoid beam operating point shift caused by space charge effect and beam loss when crossing resonance lines, the selection of the operating point needs to avoid the fourth-order system resonance line, which is most closely related to the space charge effect.

[0048] Figure 3 The schematic diagram illustrates the operating point of a proton synchrotron provided in an embodiment of the present disclosure.

[0049] like Figure 3 As shown in the figure, four operating points are displayed: (1.68, 1.23), (1.68, 1.4), (1.68, 1.62), and (1.68, 1.78). To utilize the third-order resonant slow extraction system, the horizontal operating point is typically chosen around 5 / 3 of the range. The operating point (1.68, 1.6) is close to 4V. y =6 is closer, while (1.68, 1.4) is closer to 2v. x +2v y=6 is relatively close. There are no fourth-order system resonance lines around (1.68, 1.23) and (1.68, 1.78), but during the optimization process, it was found that the vertical envelope function at point 11 of the diode is larger than that of the (1.68, 1.78) scheme, and the acceptance is smaller under the same size.

[0050] Figure 4A , 4B The illustration schematically shows the beam frequency distribution of a proton synchrotron provided in an embodiment of the present disclosure when injected at different operating points.

[0051] like Figure 4A , 4B As shown, Figure 4B The distribution in 2v is clearly affected. x +2v y =6 splits into two parts. Most of the particles near the resonance line have been lost. As the number of lost particles increases, the space charge effect weakens, and the particles below the resonance line will gradually return to the vicinity of (1.68, 1.4). During this process, they cross the resonance line, and the phenomenon of particle loss will continue. Figure 4A Since the beam does not pass through a resonant line, the frequency distribution is continuous. Although the space charge effect still exists, the beam loss is greatly reduced because it does not pass through a fourth-order resonant line.

[0052] Figure 5 The illustration schematically shows the particle survival of a proton synchrotron provided in an embodiment of the present disclosure at different operating points and injected energies.

[0053] like Figure 5 As shown, after multiple injection cycles, the horizontal root-mean-square emittance is 70π mm·mrad, the vertical root-mean-square emittance is 3.5π mm·mrad, and the total number of injected particles is 1.8E11. The aperture of the dipole iron-11 is set to 50 mm and 20 mm. If (1.68, 1.4) is used, the beam loss is very severe, and theoretically only about 5E10 particles can survive. In practical applications, extraction efficiency and subsequent transmission efficiency often need to be considered. Usually, in the best case, only 80% of the theoretical value can be achieved. However, with the optimized operating point, even at an injection energy of 3 MeV, more than 9E10 particles can survive. Even considering the practical efficiency problem, it is comparable to the beam intensity of 5E10-1E11ppp of other proton accelerators.

[0054] In synchrotrons, the main factor limiting beam current is the space charge effect. To reduce the impact of the space charge effect, common practices include using multi-turn injection or stripping injection to increase the emittance of the injected beam; increasing the energy of the injected beam; and increasing the beam aperture to increase acceptability.

[0055] The proton synchrotron provided in this disclosure employs a multi-cycle injection scheme, resulting in a larger injected beam emittance. Simultaneously, the beam envelope function is optimized, with the envelope function at the diode 11 not exceeding 5m. This leads to a smaller beam aperture for the same acceptability. Furthermore, the multi-cycle structure, combined with optimized operating point, reduces the number of system resonance lines and moves the operating point further away from them. An injection energy of only 3 MeV or higher is sufficient to achieve a storage current of 9E10ppp. The injector only requires RFQ instead of the conventional RFQ+DTL scheme, significantly reducing costs.

[0056] The proton synchrotron provided in this embodiment consists of six identical FODO units. Six focusing quadrupoles and six defocusing quadrupoles are connected in series for power supply, saving on power supply costs and facilitating operating point adjustment. Its dipole 11 is approximately 1.5m long, requiring only ±50mm and ±20mm of good field area. The overall size is small, and the weight is less than 5t, eliminating the need for a high-tonnage crane to install the magnets. The total number of cycles is six, with a phase shift of approximately 90 degrees per cycle, which physically facilitates beam extraction and reduces the intensity of the electrostatic cutter.

[0057] The synchronous loop closed-track correction of the proton synchrotron provided in this embodiment is achieved by adjusting the excitation curve of the dipole 11. Compared with other solutions, this saves the horizontal correction iron, and the number of vertical correction irons 51 is only four. The synchronous loop's lead-out resonant hexapod and chromaticity correction hexapod are integrated together, achieving the functions of resonance and chromaticity correction with only two dipoles 11. The injection and lead-out cutting magnets are located on opposite linear sections, resulting in a more reasonable distribution of injection and lead-out elements, higher space utilization of the linear sections, and a more compact layout.

[0058] Those skilled in the art will understand that the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly described in this disclosure. In particular, the features described in the various embodiments and / or claims of this disclosure can be combined or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0059] Although this disclosure has been shown and described with reference to specific exemplary embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made to this disclosure without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents. Therefore, the scope of this disclosure should not be limited to the above embodiments, but should be defined not only by the appended claims, but also by their equivalents.

Claims

1. A proton synchrotron, characterized in that, include: Six linear units are used to make the proton beam move periodically along a fixed track formed by the linear units and accelerate to increase energy. Each linear unit includes a dipole (11), a horizontal focusing quadrupole (21), a vertical focusing quadrupole (31), and a straight section. The horizontal focusing quadrupole (21) and the vertical focusing quadrupole (31) are respectively located on both sides of the dipole and connected in series on the straight section. The straight section connects the linear units in pairs to form a hexagonal ring structure. Horizontal closed track correction is performed by adjusting the excitation current ratio of the dipole (11). Two hexagonal irons (41) are respectively disposed on two symmetrically arranged straight sections in the hexagonal ring structure. The magnetic induction polarities of the two hexagonal irons (41) are opposite, and the magnetic induction intensity is configured according to a preset criterion. They cooperate with each other to independently adjust the chromaticity and resonance intensity. Four correction irons (51) are symmetrically arranged on the four straight sections of the hexagonal ring structure for vertical closed-track correction.

2. The proton synchrotron according to claim 1, characterized in that, It also includes an injection system, wherein the injection method is multi-turn injection, and the injection system includes: A cutting magnet (61) is injected and placed on a straight section where the correction iron (51) is not provided; An electrostatic injector (62) is installed on the straight section where the injector cutting magnet (61) is located; The first convex rail magnet (71), the second convex rail magnet (72), the third convex rail magnet (73) and the fourth convex rail magnet (74) are sequentially disposed on four adjacent straight sections containing the injection cutting magnet (61).

3. The proton synchrotron according to claim 2, characterized in that, It also includes an extraction system, which comprises: The cutting magnet (81) is brought out and placed on a straight section opposite to the position of the injected cutting magnet (61), adjacent to the horizontal focusing quadrupole iron (21) on the straight section. The electrostatic cutter (82) is located on a straight section adjacent to the straight section where the cut magnet (81) is located, and is adjacent to the horizontal focusing quadrupole iron (21) on the straight section. The fourth convex rail magnet (74), the fifth convex rail magnet (75) and the sixth convex rail magnet (76) are provided on a straight section opposite to the position of the fourth convex rail magnet (74), and the fifth convex rail magnet (75) is provided on the straight section where the lead-out cutting magnet (81) is located. The transverse excitation system (83) is located on any straight line node.

4. The proton synchrotron according to claim 3, characterized in that, The first convex rail magnet (71), the second convex rail magnet (72), the third convex rail magnet (73) and the fourth convex rail magnet (74) are not located on the same straight section as the lead-out cutting magnet (81) and the lead-out electrostatic cutter (82).

5. The proton synchrotron according to claim 3, characterized in that, The correction iron (51) is located on a straight section other than the straight section where the injection cutting magnet (61) and the lead-out cutting magnet (81) are located.

6. The proton synchrotron according to claim 3, characterized in that, The phase shift between the electrostatic cutter (82) and the cutting magnet (81) is 90 degrees.

7. The proton synchrotron according to claim 1, characterized in that, Also includes: Beam acceleration relies on a high-frequency accelerating cavity (91), which is installed on any straight section.

8. The proton synchrotron according to claim 1, characterized in that, The operating point of the proton synchrotron is 1.666–1.7, and the phase shift of each linear unit is 100–102 degrees. The operating point avoids the fourth-order system resonance line.

9. The proton synchrotron according to claim 1, characterized in that, The length of the dipole iron (11) is 1.5 meters, and the envelope function at the dipole iron (11) does not exceed 5 meters; the length of the straight section is 2.8 meters; and the weight of a single magnet in the proton synchrotron is less than 5 tons.

10. The proton synchrotron according to claim 1, characterized in that, The horizontal focusing quadrupole (21) has a horizontal position probe installed inside, and the vertical focusing quadrupole (31) has a vertical position probe installed inside.

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