A compact high duty cycle acceleration structure and cooling method thereof

Abstract

The present invention relates to a compact high-duty-cycle acceleration structure and a cooling method thereof. The acceleration structure includes an acceleration chamber, which is formed by a plurality of disks spaced in series. A plurality of liquid inlets and liquid outlets are staggered along the outer circumference of the disks. The plurality of liquid inlets are spaced apart along the outer circumference of the disks to form a layer, and the plurality of liquid outlets are spaced apart along the outer circumference of the disks to form another layer. The liquid inlets and liquid outlets extend toward the axis of the disks to form a liquid inlet channel and a liquid outlet channel, respectively. One liquid inlet channel is fluidically connected to two adjacent liquid outlet channels to form a cooling liquid inlet and outlet channel. The plurality of liquid inlet channels and the plurality of liquid outlet channels are fluidically connected in a one-to-two correspondence to form a plurality of parallel cooling liquid inlet and outlet channels. This acceleration structure can improve cooling efficiency, making the high-gradient acceleration structure suitable for high-duty-cycle long-pulse particle accelerators, and greatly improving the availability of particle accelerators.

Description

Technical Field

[0001] The invention relates to a compact high-duty-cycle acceleration structure and a cooling method thereof, belonging to the technical field of accelerators. Background Art

[0002] To reduce the construction cost and land area of ​​particle accelerators, accelerator miniaturization has become a goal of accelerator technology. High-gradient accelerating structures are key components for particle accelerator miniaturization. High-frequency (S, C, X-band, etc.) single-cycle accelerating structures can achieve acceleration gradients exceeding 50 MV / m. RF cavities are typically fabricated from non-ideal conductors with finite conductivity. High-frequency losses during field generation are deposited as heat on the high-frequency surfaces of the cavity. For ultra-high-frequency RF cavities, the small cavity size makes it difficult to pass water through the accelerating structure. Currently, the temperature rise of the RF cavity is reduced by adding cooling plates to the outside of the accelerating structure. This method removes limited heat and is only suitable for accelerators with extremely low duty cycles (less than 1 / 10,000). As the duty cycle increases, excessive thermal stress generated by the high-frequency losses in the cavity during operation, leading to deformation of the accelerating structure, is a major problem facing this type of accelerating structure. Summary of the Invention

[0003] To address the above technical issues, the present invention provides a compact high-duty-cycle accelerating structure and a cooling method thereof. This accelerating structure designs a cooling channel inside a thin accelerating structure with a thickness of only 3 mm. Brazing or 3D printing technology is used to make the disk of the radio frequency cavity hollow. Coolant is then introduced into the disk to improve cooling efficiency, making the high-gradient accelerating structure suitable for high-duty-cycle long-pulse particle accelerators, thereby greatly improving the availability of particle accelerators.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A compact high duty cycle acceleration structure comprising:

[0006] An acceleration chamber, wherein the acceleration chamber is formed by a plurality of disks connected in series at intervals, and a plurality of liquid inlets and liquid outlets are arranged alternately along the outer circumference of the disks, wherein the plurality of liquid inlets are arranged at intervals along the outer circumference of the disks to form a layer, and the plurality of liquid outlets are arranged at intervals along the outer circumference of the disks to form another layer;

[0007] The liquid inlet and the liquid outlet extend toward the axial direction of the disc, respectively, to form a liquid inlet channel and a liquid outlet channel, respectively. One liquid inlet channel and two adjacent liquid outlet channels are fluidically connected to form a cooling liquid inlet and outlet channel. Several liquid inlet channels and several liquid outlet channels are fluidically connected in a one-to-two correspondence manner to form several parallel cooling liquid inlet and outlet channels.

[0008] The compact high duty cycle acceleration structure is preferably provided with a plurality of coupling holes evenly arranged along its circumference, and the plurality of liquid outlet channels are arranged in a one-to-one correspondence with the plurality of coupling holes, and the liquid outlet channels surround the coupling holes.

[0009] The compact high-duty-cycle acceleration structure preferably has a symmetrical distribution structure of the liquid outlet channel as a whole with the coupling hole as the center, and the end of the liquid outlet channel connected to the liquid outlet is composed of two arc-shaped guide plates expanding outward away from the coupling hole, and the end away from the liquid outlet is composed of two straight-line guide plates.

[0010] In the compact high duty cycle acceleration structure, preferably, two adjacent sections of guide plates close to each other at two adjacent liquid outlet channels define the liquid inlet channel.

[0011] In the compact high duty cycle acceleration structure, preferably, a coupling hole guide plate is provided on the coupling hole, and the coupling hole guide plate extends in the radial direction of the disk.

[0012] In the compact high duty cycle acceleration structure, preferably, a liquid outlet channel guide plate is provided in the liquid outlet channel.

[0013] In the compact high duty cycle acceleration structure, preferably, a groove is provided on the outer circumference of the disc, and a sealing ring is provided in the groove to separate the liquid inlet and the liquid outlet.

[0014] In the compact high duty cycle acceleration structure, preferably, the liquid inlet, the liquid outlet, the liquid inlet flow channel and the liquid outlet flow channel are realized by brazing or 3D printing technology.

[0015] A second aspect of the present invention provides a cooling method for the above-mentioned compact high duty cycle acceleration structure, comprising the following steps:

[0016] Connect several of the liquid inlets to an external coolant delivery pipe, and connect several of the liquid outlets to an external coolant recovery pipe. When the acceleration cavity is working, coolant is introduced. The coolant reduces the thermal stress of the acceleration cavity caused by temperature rise and avoids the occurrence of plastic deformation of the cavity.

[0017] The present invention has the following advantages due to the adoption of the above technical solution:

[0018] 1. The present invention designs a cooling channel inside a thin accelerating structure with a thickness of only 3 mm. Brazing or 3D printing technology is used to make the disk of the radio frequency cavity hollow. Cooling liquid is passed into the disk to improve cooling efficiency, making the high-gradient accelerating structure suitable for high-duty-cycle long-pulse particle accelerators, greatly improving the availability of particle accelerators.

[0019] 2. By designing inlet and outlet coolant flow channels inside the disk, the present invention can directly carry away the high-frequency heat generated by the high-frequency resonant cavity with the coolant, greatly improving the cooling efficiency and making the high-gradient acceleration structure suitable for high-duty-cycle long-pulse particle accelerators. The duty cycle is improved by 2-3 orders of magnitude compared to the existing technical level, thereby improving the availability of the accelerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of a magnetically coupled accelerating cavity disk with a nose cone provided by one embodiment of the present invention;

[0021] Figure 2 is a perspective view of a disc provided by this embodiment of the present invention;

[0022] Figure 3 is a cross-sectional view of a disc provided by this embodiment of the present invention;

[0023] Figure 4 A temperature distribution diagram on the disk provided in this embodiment of the present invention;

[0024] Figure 5 A diagram showing the pressure distribution of the liquid inlet and outlet channels on the disk provided in this embodiment of the present invention;

[0025] The reference numerals in the figures are as follows:

[0026] 1-disc; 2-liquid outlet; 3-liquid inlet; 4-liquid outlet channel; 5-liquid inlet channel; 6-coupling hole; 7-guide plate; 8-coupling hole guide plate; 9-liquid inlet channel guide plate. DETAILED DESCRIPTION

[0027] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention are described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments derived by ordinary persons in this field based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] For an RF resonant cavity of a defined shape, the spatial distribution of the electromagnetic field within the cavity is also determined. The high-frequency electromagnetic field within the cavity generates high-frequency heat, which is dissipated to the cavity walls, causing the wall temperature to rise. For a room-temperature cavity, the temperature rise generates thermal stress due to the thermal expansion and contraction of the material. When the thermal stress exceeds the yield strength of the cavity material, the cavity undergoes plastic deformation, making it impossible to stably establish the desired operating mode. Typically, cooling channels are designed within the room-temperature cavity to dissipate the high-frequency heat from the cavity walls with coolant, keeping the surface thermal stress below the material's yield stress. Ultra-high-frequency accelerating structures are extremely compact, making it difficult to flow water through the structure using conventional machining processes. Cooling is only achieved externally through coiled water pipes or water jackets. This approach effectively cools only the areas closest to the cooling channels, making it difficult to conduct heat away from the accelerating structure. Consequently, existing high-gradient accelerating structures typically operate at extremely low duty cycles.

[0029] To address these issues, the present invention creates layered cooling channels for the inlet and outlet of the high-frequency resonant cavity disk. These channels are connected in parallel to minimize fluid flow resistance, minimizing the disk's mechanical strength. Furthermore, the disk's interior is hollowed out as much as possible to reduce the distance for heat conduction, allowing for direct heat dissipation through the fluid and improving cooling efficiency. Because disks are typically thin, they are manufactured using brazing or 3D printing techniques. A sealing ring separates the disk's liquid inlet and outlet, allowing the coolant to circulate within the disk for cooling.

[0030] The technical solution of the present invention is described in detail below with reference to the accompanying drawings.

[0031] like Figure 1 As shown, the compact high duty cycle acceleration structure provided by the present invention includes an acceleration cavity, which is formed by a plurality of disks 1 connected in series at intervals, and a plurality of liquid inlets 3 and a plurality of liquid outlets 2 are arranged alternately along the outer circumferential direction of the disk 1, wherein the plurality of liquid inlets 3 are arranged at intervals in the outer circumferential direction of the disk 1 and form a layer, and the plurality of liquid outlets 2 are arranged at intervals in the outer circumferential direction of the disk 1 and form another layer; of course, multiple layers of liquid inlets 3 and liquid outlets 2 can be set in the outer circumference of the disk 1, and the present invention does not limit the number of layers of liquid inlets 3 and liquid outlets 2.

[0032] like Figure 2 、 Figure 3 As shown, the liquid inlet 3 and the liquid outlet 2 extend toward the axial direction of the disc 1, respectively forming a liquid inlet channel 5 and a liquid outlet channel 4, respectively. One liquid inlet channel 5 and two adjacent liquid outlet channels 4 are fluidically connected to form a coolant inlet and outlet channel, and several liquid inlet channels 5 and several liquid outlet channels 4 are fluidically connected in a one-to-two correspondence to form several parallel coolant inlet and outlet channels.

[0033] like Figure 3 As shown, the disc 1 is provided with a plurality of coupling holes 6 evenly arranged along its circumference, and the plurality of liquid outlet channels 4 are arranged in one-to-one correspondence with the plurality of coupling holes 6 , and the liquid outlet channels 4 surround the coupling holes 6 .

[0034] In a preferred embodiment of the present invention, Figure 3 As shown, the liquid outlet channel 4 is symmetrically distributed around the coupling hole 6. The end of the liquid outlet channel 4 connected to the liquid outlet 2 is composed of two curved guide plates that expand outward away from the coupling hole 6, while the end away from the liquid outlet 2 is composed of two straight guide plates. This preferred embodiment is the result of continuous optimization by the inventors to design the liquid inlet channel 5 and liquid outlet channel 4. This embodiment can maximize the temperature reduction of the disk 1.

[0035] Furthermore, two adjacent sections of the guide plates 7 close to each other of the two adjacent liquid outlet channels 4 define the liquid inlet channel 5 .

[0036] In one embodiment of the present invention, Figure 3 As shown, the coupling hole 6 is provided with a coupling hole guide plate 8, which extends radially along the disk 1, and the liquid inlet flow channel 5 is provided with a liquid inlet flow channel guide plate 9. This can improve the overall strength of the disk 1 and prevent the beam from damaging the disk 1.

[0037] Furthermore, the liquid inlet 3, the liquid outlet 2, the liquid inlet channel 5 and the liquid outlet channel 4 in the present invention are realized by brazing or 3D printing technology.

[0038] A second aspect of the present invention provides a cooling method for the above-mentioned compact high duty cycle acceleration structure, comprising the following steps:

[0039] Connect several of the liquid inlets 3 to the external coolant delivery pipeline, and connect several of the liquid outlets 2 to the external coolant recovery pipeline. When the acceleration cavity is working, coolant is introduced. The coolant reduces the thermal stress of the acceleration cavity caused by temperature rise and avoids the occurrence of plastic deformation of the cavity.

[0040] The present invention designs coolant inlet and outlet channels in layers on the high-frequency resonant cavity disk 1, utilizing parallel channels to minimize liquid flow resistance without affecting the mechanical strength of the disk 1. Furthermore, the interior of the disk 1 is hollowed out as much as possible to reduce the distance for heat conduction, allowing direct heat dissipation through the fluid and improving cooling efficiency. Because the disk 1 is generally thin, it is manufactured using brazing or 3D printing technology, and a sealing ring is used to separate the disk's liquid inlet and outlet, allowing the coolant to circulate and cool the disk.

[0041] like Figure 1 As shown, taking the magnetically coupled accelerating cavity with nose cone as an example, parallel channels are used to minimize the coolant flow resistance, and six inlet and six outlet coolant flow channels are designed in layers on the disk 1, where the upper layer is the liquid inlet and the lower layer is the liquid outlet, and three sealing rings are used to separate the liquid inlet and the liquid outlet. Taking water as the coolant as an example, for an RF cavity with a certain geometric structure and a given thermal power density distribution, the traditional external water cooling solution can control the temperature rise of the cavity to about 35K. The accelerating cavity of the present invention can control the temperature rise of the same cavity to 16K when the water flow rate is 1.5L / min, and the pressure difference is only 0.7kPa.

[0042] By designing inlet and outlet coolant flow channels inside the disk 1, the present invention can directly carry away the high-frequency heat generated by the high-frequency resonant cavity with the coolant, greatly improving the cooling efficiency and making the high-gradient acceleration structure suitable for high-duty-cycle long-pulse particle accelerators. The duty cycle is improved by 2-3 orders of magnitude compared to the existing technical level, thereby improving the availability of the accelerator.

[0043] The present invention also provides an application of the above-mentioned compact high-duty-cycle acceleration structure in ion radiotherapy and proton FLASH cancer therapy.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A compact high duty cycle acceleration structure, characterized in that: include: An acceleration cavity, the acceleration cavity being formed by a plurality of disks (1) connected in series at intervals, a plurality of liquid inlets (3) and a plurality of liquid outlets (2) being arranged alternately along the outer circumferential direction of the disks (1), the plurality of liquid inlets (3) being arranged at intervals in the outer circumferential direction of the disks (1) to form a layer, and the plurality of liquid outlets (2) being arranged at intervals in the outer circumferential direction of the disks (1) to form another layer; The liquid inlet (3) and the liquid outlet (2) extend toward the axial direction of the disk (1) to form a liquid inlet channel (5) and a liquid outlet channel (4), respectively. One liquid inlet channel (5) and two adjacent liquid outlet channels (4) are fluidically connected to form a cooling liquid inlet and outlet channel. Several liquid inlet channels (5) and several liquid outlet channels (4) are fluidically connected in a one-to-two correspondence manner to form several parallel cooling liquid inlet and outlet channels.

2. The compact high duty cycle acceleration structure according to claim 1, characterized in that: The disc (1) is provided with a plurality of coupling holes (6) uniformly arranged along its circumference, the plurality of liquid outlet channels (4) are arranged in one-to-one correspondence with the plurality of coupling holes (6), and the liquid outlet channels (4) surround the coupling holes (6).

3. The compact high duty cycle acceleration structure according to claim 2, characterized in that: The liquid outlet flow channel (4) as a whole presents a symmetrical distribution structure centered on the coupling hole (6); the end of the liquid outlet flow channel (4) connected to the liquid outlet (2) comprises two arc-shaped flow guide plates that expand outward away from the coupling hole (6); and the end away from the liquid outlet (2) comprises two straight-line flow guide plates.

4. The compact high duty cycle acceleration structure according to claim 3, characterized in that: Two sections of guide plates (7) close to each other of two adjacent liquid outlet channels (4) define the liquid inlet channel (5).

5. The compact high duty cycle acceleration structure according to claim 2, characterized in that: A coupling hole guide plate (8) is provided on the coupling hole (6), and the coupling hole guide plate (8) extends in the radial direction of the disc (1).

6. The compact high duty cycle acceleration structure according to claim 1, characterized in that: A liquid outlet channel guide plate (9) is provided in the liquid outlet channel (4).

7. The compact high duty cycle acceleration structure according to claim 1, characterized in that: A groove is provided on the outer circumference of the disc (1), and a sealing ring is provided in the groove for separating the liquid inlet (3) and the liquid outlet (2).

8. The compact high duty cycle acceleration structure according to claim 1, characterized in that: The liquid inlet (3), the liquid outlet (2), the liquid inlet flow channel (5) and the liquid outlet flow channel (4) are realized by brazing or 3D printing technology.

9. A cooling method for the compact high duty cycle acceleration structure according to any one of claims 1 to 7, characterized in that: The steps include: The plurality of liquid inlets (3) are connected to an external cooling liquid delivery pipeline, and the plurality of liquid outlets (2) are connected to an external cooling liquid recovery pipeline. When the acceleration cavity is working, cooling liquid is introduced. The cooling liquid reduces the thermal stress of the acceleration cavity caused by the temperature rise, thereby avoiding the occurrence of plastic deformation of the cavity.

Images