An internally cooled high frequency coupling window for a high power cyclotron

Abstract

The application discloses an internal cooling based high-frequency coupling window for a high-power cyclotron, which is characterized in that: a wind knife structure is arranged on the atmospheric end of the internal cooling based high-frequency coupling window; two groups of conductor choke units with different lengths are arranged on the two sides of a ceramic sheet of the internal cooling based high-frequency coupling window, the two groups of conductor choke units with different lengths are equivalent to two groups of inductors, and are used for forming a double filter circuit of the high-frequency coupling window; a ceramic coating is arranged on one side of the ceramic sheet of the high-frequency coupling window; the wind knife structure is used for taking away more heat on the surface of the ceramic sheet through compressed air; and the wind knife structure and the conductor choke units are used for forming a filter circuit of the atmospheric end of the high-frequency coupling window; the wind knife structure is used for enhancing the cooling of the ceramic sheet of the coupling window structure; the conductor choke units are used for adjusting the inductance value of the coupling window, reducing the standing wave ratio coefficient of the coupling window, reducing the surface temperature of the ceramic sheet, and reducing the risk of explosion of the coupling window.

Description

Technical Field

[0001] This invention belongs to the field of cyclotron technology, and more specifically, relates to a high-frequency coupling window based on internal cooling for a high-power cyclotron. Background Technology

[0002] The coupling window is an important component for feeding power into a cyclotron.

[0003] The design challenges of the high-frequency coupling window for high-power cyclotrons are as follows: First, because it is a high-power cyclotron, the power fed into the cyclotron through the coupling window is very high, resulting in a relatively large amount of heat generated by the high power. Second, the outer conductor of the high-power coupling window is easy to dissipate heat, but the ceramic plate on the inner conductor is not easy to dissipate heat. This is because the ceramic plate is located inside the coupling window. Since the coupling window is a fixed component, it is not easy to add a water cooling device inside once it is formed. Therefore, a feasible way to dissipate heat from the ceramic plate inside the coupling window has never been found.

[0004] The reason why the ceramic plate inside the coupling window needs heat dissipation is that when the transmitted power is too high, a large number of secondary electrons will escape from the ceramic surface of the coupling window under the influence of the secondary electron multiplication effect, making the ceramic susceptible to breakdown. In addition, at the connection between the ceramic plate and the inner and outer conductors at the vacuum end of the ceramic window, arcing can occur, causing metal vapor to escape rapidly and react on the surface of the ceramic plate, resulting in an increase in the surface temperature of the ceramic plate. Uneven heating can then cause the ceramic plate to crack.

[0005] In this field, heat dissipation for high-power coupling windows is generally limited to dissipating heat from the outer conductor of the coupling window, indirectly dissipating heat from the inner conductor of the coupling window by dissipating heat from the outer conductor, or using natural cooling. These methods cannot achieve the ideal cooling effect for the ceramic sheet and effectively protect the ceramic sheet structure in the coupling window.

[0006] In summary, the relatively mature cyclotron coupling window design in engineering practice is based on low-power coupling window design, while there is no precedent for high-power coupling window design. Therefore, the design of coupling windows is limited by both low feed power efficiency and susceptibility to damage when fed with high-power signals, which greatly restricts the application scope and economic improvement of high-power cyclotron coupling windows. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention proposes a high-frequency coupling window based on internal cooling for high-power cyclotrons. The aim is to solve the dual limitations of existing coupling window designs, which are subject to low feed power efficiency and susceptibility to damage when fed with high-power signals.

[0008] To solve its technical problems, the present invention proposes the following technical solutions:

[0009] A high-frequency coupling window based on internal cooling for high-power cyclotrons is proposed.

[0010] A high-frequency coupling window based on internal cooling for a high-power cyclotron is characterized by: an air knife structure (2) at the atmospheric end of the high-frequency coupling window based on internal cooling; two sets of conductor choke units of unequal lengths on the outer and inner conductors on both sides of the ceramic sheet (1-4) of the high-frequency coupling window based on internal cooling, the two sets of inner conductor choke units (1-2) of unequal lengths being equivalent to two sets of inductors, used to form a dual filter circuit for the high-frequency coupling window; and a ceramic coating (1-3) on one side of the ceramic sheet (1-4) of the high-frequency coupling window based on internal cooling.

[0011] The air knife structure (2) increases the air velocity on the surface of the ceramic sheet by compressing air to remove more heat from the surface of the ceramic sheet; and together with the conductor choke unit, it forms a filter circuit at the atmospheric end of the high-frequency coupling window, which further reduces the power heat absorbed by the ceramic sheet (1-4) of the high-frequency coupling window through the filter circuit at the atmospheric end.

[0012] The ceramic coating (1-3) is a ceramic coating of a set thickness. The ceramic coating (1-3) of the set thickness can protect the ceramic from electron bombardment and accept as little high power as possible, thereby further reducing the power heat absorbed by the high frequency coupling window ceramic sheet (1-4).

[0013] Furthermore, the high-frequency coupling window based on internal cooling includes: a cylindrical high-frequency coupling window (1), an inner conductor (1-1) and an outer conductor (1-2) arranged along the axial direction of the cylindrical high-frequency coupling window, with the outer conductor (1-2) surrounding the inner conductor (1-1); a ceramic plate (1-4) traversing and perpendicular to the inner conductor (1-1) and the outer conductor (1-2); one side of the ceramic plate (1-4) is a vacuum cavity, and the other side is an atmospheric cavity; a cylindrical air knife structure (2) is connected to the outer end face of the atmospheric cavity, the air knife structure (2) including an inner conductor (2-1), an outer conductor (2-2), and an air knife slit structure (2-3) arranged between the inner conductor (2-1) and the outer conductor (2-2). The slit structure (2-3) is welded to the inner surface of the outer conductor (2-2) of the air knife; the inner conductor (2-1) of the air knife and the inner conductor (1-1) of the coupling window have the same diameter and are connected, the outer conductor (2-2) of the air knife and the outer conductor (1-2) of the coupling window have the same diameter and are connected, the atmosphere enters from the air inlet (2-4) of the air knife, passes through the gap of the slit structure (2-3) of the air knife to the inner conductor (2-1) of the air knife structure and the inner conductor (1-1-1-1) of the coupling window, then from the inner conductor (1-1-1-1) of the coupling window to the ceramic plate (1-4), from the ceramic plate (1-4) to the air outlet (1-5) of the coupling window, and finally exhausts the hot air into the atmosphere, thus forming a heat dissipation channel from the air inlet (2-4) of the air knife to the air outlet (1-5) of the coupling window, which is specifically for dissipating heat from the ceramic plate (1-4).

[0014] Furthermore, the ceramic coating (1-3) of a predetermined thickness is disposed on the side of the ceramic sheet (1-4) facing the vacuum cavity, and the ceramic coating (1-3) is no greater than The TiN coating, which is no larger than The TiN coating can protect (1-5) from electron bombardment and minimize the amount of high power it receives, thereby further reducing the power heat absorbed by the high-frequency coupling window ceramic sheet (1-4).

[0015] Furthermore, the air knife structure (2) is made of Teflon material and is connected to the atmospheric end of the high-frequency coupling window by means of screws through a flange structure, so as to directly cool the ceramic plate structure of the coupling window.

[0016] Furthermore, the air knife slit structure (2-3) consists of an upper slit structure (2-3-1) and a lower slit structure (2-3-2); the upper slit structure (2-3-1) and the lower slit structure (2-3-2) form a low-speed narrow zone (2-5-1), a dust adsorption zone (2-5-2), and a wide acceleration zone (2-5-3) from the outside in; the slit in the low-speed narrow zone (2-5-1) is relatively narrow and has relatively high pressure and relatively low wind speed; the dust adsorption zone (2-5-2) is provided with a downwardly recessed O-ring groove, which is used to arrange O-rings to block dust, and the top of the O-ring and the upper slit structure (2-3-1) form a slit area with the narrowest gap; the wide acceleration zone (2-5-3) is adjacent to the dust adsorption zone, and the wide acceleration zone ( The gap in 2-5-2 widens, causing the pressure in the area to drop sharply and the wind speed to increase sharply. The bottom of the gap in the wide acceleration zone (2-5-2) is shaped like a boat with both ends curving upwards. One end of the boat shape is connected to the dust adsorption area, and the other end is matched with the tongue shape of the upper layer of the slit structure (2-3-1), forming a vertical atmospheric channel at the "stern". After the air enters the "boat-shaped" area from the dust adsorption area, it generates an upward vortex airflow. The vortex airflow then flows out from the vertical atmospheric channel at the "stern" and is sprayed vertically onto the inner conductor (2-1) of the wind knife structure. The inner conductor (2-1) of the wind knife structure and the inner conductor (1-1-1) of the coupling window cool the ceramic plate (1-4) connected to the inner conductor (1-1-1).

[0017] Furthermore, the two sets of conductor choke units of unequal length refer to the following: with the ceramic sheet (1-4) as the boundary, the outer conductor choke unit and the inner conductor choke unit on the vacuum side of the ceramic sheet (1-4) form one set; the outer conductor choke unit and the inner conductor choke unit on the atmospheric side of the ceramic sheet (1-4) form another set. The unequal length means that the conductor choke unit on the inner conductor of each set of conductor choke units has a different length than the conductor choke unit on the outer conductor, but the outer conductor choke units on both sides of the ceramic sheet (1-4) have the same length, and the inner conductor choke units have the same length.

[0018] Furthermore, the length of the conductor choke unit on one side of the outer conductor is relatively long at 6 mm, while the length on the other side of the inner conductor is relatively short at 4.49 mm.

[0019] Furthermore, the cylindrical high-frequency coupling window (1) is equivalent to a capacitor C2 located between the inner conductor (1-1) and the outer conductor (1-2) of the coupling window, and the cylindrical air knife structure (2) is equivalent to a capacitor C1 located between the inner conductor (2-1) and the outer conductor (2-2) of the air knife. After adding the air knife structure (2), it is equivalent to connecting a capacitor C1 in parallel after the capacitor C2 corresponding to the cylindrical high-frequency coupling window (1). The capacitor C1 and the first set of conductor choke units L1 and L3 form the first filter circuit. The capacitor C2 and the second set of conductor choke units L2 and L4 form the second filter circuit.

[0020] Advantages and effects of the present invention

[0021] This invention ingeniously utilizes an air knife structure to enhance the cooling of the ceramic sheet in the coupling window structure. A TiN coating is applied to the vacuum side of the ceramic sheet to reduce the secondary electron emission coefficient, minimizing the secondary electron multiplication effect. A simpler method for inspecting the TiN coating thickness is also employed. A conductor choke unit is used to adjust the inductance of the coupling window, reducing its VSWR. Ultimately, this achieves stable operation of the coupling window under high duty cycle and high power conditions, lowering the ceramic sheet surface temperature and reducing the risk of coupling window cracking. This invention fulfills the design goals of low loss, high transmission efficiency, and reduced temperature rise in the coupling window. Attached Figure Description

[0022] Figure 1 This is an application effect diagram of the coupling window heat dissipation device of the present invention;

[0023] Figure 2 This is an external view of the coupling window heat dissipation device of the present invention;

[0024] Figure 3 This is a cross-sectional view of the coupling window heat dissipation device of the present invention;

[0025] Figure 4 This is a cross-sectional view of the air knife slit structure of the coupling window heat dissipation device of the present invention;

[0026] Figure 5 This is an equivalent circuit diagram of the coupling window heat dissipation device of the present invention.

[0027] In the diagram: 1: High-frequency coupling window; 1-1-1: Inner conductor of coupling window; 1-1-2: Outer conductor of coupling window; 1-2: Choke unit of inner conductor; 1-3: Ceramic coating; 1-4: Ceramic sheet; 1-5: Air outlet of coupling window; 2: Air knife structure; 2-1: Inner conductor of air knife; 2-2: Outer conductor of air knife; 2-3: Slit structure of air knife; 2-3-1: Upper layer of slit structure; 2-3-2: Lower layer of slit structure; 2-4: Air inlet of air knife; 2-5-1: Low-speed narrow zone; 2-5-2: Dust adsorption zone; 2-5-3: Spacious acceleration zone; Detailed Implementation

[0028] The invention will be further explained below with reference to the accompanying drawings.

[0029] Design principle of the invention

[0030] 1. Innovation of this invention: The innovation lies in comprehensively considering and synergistically solving multiple elements that generate heat within the coupling window, including the heat generated when the coupling window feeds high power into the high-frequency cavity, the heat generated by the heating element (ceramic coating) inside the coupling window, and the heat generated by the power corresponding to the invalid electrical signal inside the coupling window. Reducing these three types of heat is interdependent; improper handling of any one will lead to uneven heating of the ceramic sheet surface, causing it to crack. If only the air knife structure 2 at the atmospheric end of the coupling window is added, and the air is compressed to dissipate heat from the two inner conductors and the ceramic sheet surface, while neglecting the design of the ceramic coating thickness, the result will be even worse. This is because the ceramic coating is directly applied to the ceramic sheet, and since the ceramic coating is a metal heating element, the thicker the heating element, the higher the heat generation. If only the problems of high-power heat generation and heating element heat generation are solved, but effective filtering of high-power noise signals is not performed, then the air knife cooling and ceramic coating cooling will be less effective and will not achieve the desired results.

[0031] 2. Design Principle of the Wind Knife Slit Structure: The bottom shape of the spacious acceleration zone 2-5-2 slit of the wind knife slit structure 2-3 is a "boat" shape with both ends curving upwards. One end of the "boat" shape connects to the dust adsorption zone, and the other end matches the tongue shape of the upper layer 2-3-1 of the slit structure, forming a downward vertical atmospheric channel at the "stern". The design principle of this "boat" shaped slit and the downward vertical atmospheric channel is as follows:

[0032] First, it acts as a guide, fine-tuning the distribution and direction of compressed air to ensure a uniform and concentrated gas flow rate, thereby achieving a more efficient injection effect. This design ensures a uniform airflow tangential and prevents excessively rapid airflow diffusion.

[0033] Secondly, this location is designed as a transitional flow guide structure to reduce airflow turbulence. Reducing turbulence helps improve airflow stability and exit velocity, thereby increasing the efficiency of the air knife. The circled portion acts as an air rectifier, ensuring that the airflow forms a laminar state at the exit.

[0034] Third, by designing such a structure, the rigidity of the air knife edge is strengthened, thereby avoiding deformation caused by vibration or airflow impact during long-term operation.

[0035] 3. Design Principle of Ceramic Coating. The function of the ceramic coating 1-3 is to protect the ceramic sheet 1-4 from electron bombardment. If it is too thin, it will not provide protection; however, if it is too thick, it will be dangerous because it is itself a heat-generating element and acts directly on the ceramic sheet 1-4. Therefore, both excessively thin and excessively thick coatings are problematic. In this invention, the ceramic coating 1-3 is no larger than... The TiN coating, which is no larger than The TiN coating can protect 1-5 from electron bombardment while minimizing the amount of high power it receives, thereby further reducing the power heat absorbed by the high-frequency coupling window ceramic plates 1-4. The principle is as follows:

[0036] 1) Calculate the acceptable range of loss values: The coupling window before and after TiN coating was tested using a vector network analyzer, and the test results are shown in Table 1. Table 1 demonstrates that when a TiN coating is applied to ceramic sheets 1-4, the TiN coating exhibits ohmic loss. Therefore, the simple test method of verifying whether the coating meets the design objectives by measuring the resistance values ​​of the ceramic sheet structure and the TiN coating is reasonable.

[0037] Table 1. Insertion loss values ​​S before and after TiN coating. 21

[0038]

[0039] The insertion loss value refers to the power loss of the input power signal at the coating location due to the ohmic loss of the coating. When the input power is 40KW, and the insertion loss value S21 < -0.01dB, the power loss is less than 400W, which is acceptable in engineering practice. Therefore, we consider that when the measured insertion loss value S21 < -0.01dB, the TiN coating thickness is acceptable in engineering practice.

[0040] 2) Calculate the thickness of ceramic coating 1-4 using a reasonable loss value S21 < -0.01dB.

[0041] First, the measured S21 is converted into a linear value. When the input power is 40KW, the power lost during coating is 92W. Given that the equivalent resistance of the coupling window structure is 50Ω, the current through the coating can be calculated to be approximately 28.28A. Using the resistance calculation formula, the resistance of the coating is approximately 0.115Ω. The resistivity of TiN material is approximately 0.2mΩ / m, the radius of the ceramic sheet is 61.99mm, and the effective coverage width is approximately 100mm. Therefore, the calculated coating thickness is approximately 6nm.

[0042] 4. Design principle of the conductor choke unit: The conductor choke unit of this invention is designed to be asymmetrical. The asymmetry means that the lengths of the conductor choke unit on the inner conductor and the conductor choke unit on the outer conductor are not the same. The length of the conductor choke unit on the outer conductor side is relatively longer (6mm), while the length on the inner conductor side is relatively shorter (4.49mm).

[0043] (1) The different positions and functions of the inner and outer conductors in the electromagnetic coupling window structure lead to significant differences in their electromagnetic environment. The electric field strength near the inner conductor is relatively high and the magnetic field strength is relatively low, so its conductor choke unit structure is required to have a lower inductance to reduce parasitic inductance; the electric field strength of the outer conductor is relatively low and the magnetic field strength is relatively high, so the outer conductor, as the shell, suppresses external interference signals and avoids signal leakage from the inner conductor, requiring a higher inductance to optimize the shielding effect of the magnetic field.

[0044] (2) In the coupling window structure, the asymmetrical inductor design can better control the directionality of energy transmission. ① Reduce the reflection coefficient: By adjusting the electromagnetic field coupling characteristics of the inner and outer conductors through asymmetrical inductor distribution, the standing wave ratio is reduced, thereby improving signal transmission efficiency. ② Optimize power distribution: The difference between the inner and outer inductors can achieve precise control of high-frequency power flow and reduce energy loss.

[0045] (3) The higher inductance of the outer conductor choke unit structure enables the coupling window to form a specific resonant point to suppress non-target frequency signals. The lower inductance of the inner conductor choke unit structure avoids resonant interference in the target frequency range, thereby improving the transmission quality of the target signal.

[0046] Based on the above principles, this invention designs an internally cooled high-frequency coupling window for high-power cyclotron accelerators, such as... Figure 1 , Figure 2 , Figure 3 As shown, its features are: an air knife structure 2 is provided at the atmospheric end of the high-frequency coupling window based on internal cooling; two sets of conductor choke units of unequal lengths are provided on the outer conductor and inner conductor on both sides of the ceramic sheet 1-4 of the high-frequency coupling window based on internal cooling, and the two sets of inner conductor choke units 1-2 of unequal lengths are equivalent to two sets of inductors, which are used to form a dual filter circuit of the high-frequency coupling window; a ceramic coating 1-3 is provided on one side of the ceramic sheet 1-4 of the high-frequency coupling window based on internal cooling.

[0047] The air knife structure 2 increases the air velocity on the surface of the ceramic sheet by compressing air to remove more heat from the surface of the ceramic sheet; on the other hand, together with the conductor choke unit, it forms a filter circuit at the atmospheric end of the high-frequency coupling window, which further reduces the power heat absorbed by the ceramic sheets 1-4 of the high-frequency coupling window through the filter circuit at the atmospheric end.

[0048] The ceramic coating 1-3 is a ceramic coating of a set thickness. The ceramic coating 1-3 of the set thickness can protect the ceramic from electron bombardment and minimize the amount of high power it receives, thereby further reducing the power heat absorbed by the high frequency coupling window ceramic sheet 1-4.

[0049] Supplementary Note 1

[0050] like Figure 1 As shown, in this embodiment, an internally cooled high-frequency coupling window is used to feed power into the high-frequency cavity of the cyclotron. A transmission line is provided between the internally cooled high-frequency coupling window and the high-frequency cavity, and high power is fed into the high-frequency cavity of the cyclotron through the transmission line.

[0051] like Figure 2 , Figure 3 As shown, the high-frequency coupling window based on internal cooling includes: a cylindrical high-frequency coupling window 1, an inner conductor 1-1-1 and an outer conductor 1-1-2 arranged along the axial direction of the cylindrical high-frequency coupling window, with the outer conductor 1-1-2 surrounding the inner conductor 1-1-1; a ceramic plate 1-4 traversing and perpendicular to the inner conductor 1-1-1 and the outer conductor 1-1-2; one side of the ceramic plate 1-4 is a vacuum cavity, and the other side is an atmospheric cavity; a cylindrical air knife structure 2 is connected to the outer end face of the atmospheric cavity, the air knife structure 2 including an inner conductor 2-1, an outer conductor 2-2, an air knife slit structure 2-3 arranged between the inner conductor 2-1 and the outer conductor 2-2, and an air knife inlet. Air inlet 2-4, the air knife slit structure 2-3 is welded to the inner surface of the outer conductor 2-2 of the air knife; the inner conductor 2-1 of the air knife and the inner conductor 1-1-1 of the coupling window have the same diameter and are connected, the outer conductor 2-2 of the air knife and the outer conductor 1-1-2 of the coupling window have the same diameter and are connected, the atmosphere enters from the air inlet 2-4 of the air knife, passes through the gap of the air knife slit structure 2-3 to the inner conductor 2-1 of the air knife structure and the inner conductor 1-1-1 of the coupling window, then from the inner conductor 1-1-1 of the coupling window to the ceramic plate 1-4, from the ceramic plate 1-4 to the air outlet 1-5 of the coupling window, and finally exhausts the hot air into the atmosphere, thus forming a heat dissipation channel from the air inlet 2-4 of the air knife to the air outlet 1-5 of the coupling window specifically for dissipating heat from the ceramic plate 1-4.

[0052] like Figure 2 As shown, the ceramic coating 1-3 of a set thickness is arranged on the side of the ceramic sheet 1-4 facing the vacuum cavity. The ceramic coating 1-3 is a TiN coating with a thickness of no more than 6 mm. This TiN coating with a thickness of no more than 6 mm can protect the ceramic sheet 1-4 from electron bombardment and minimize the amount of high power it receives, thereby further reducing the power heat absorbed by the high-frequency coupling window ceramic sheet 1-4.

[0053] like Figure 2As shown, the air knife structure 2 is made of Teflon and is connected to the atmospheric end of the high-frequency coupling window via a flange structure and screws, in order to directly cool the ceramic plate structure of the coupling window.

[0054] like Figure 3 , Figure 4 As shown, the air knife slit structure 2-3 consists of an upper slit structure 2-3-1 and a lower slit structure 2-3-2. The upper slit structure 2-3-1 and the lower slit structure 2-3-2 form a low-speed narrow zone 2-5-1, a dust adsorption zone 2-5-2, and a wide acceleration zone 2-5-3, arranged from the outside inwards. The slit in the low-speed narrow zone is relatively narrow with relatively high pressure and relatively low wind speed. The dust adsorption zone 2-5-2 is provided with a downwardly recessed O-ring groove, which is used to arrange O-rings to block dust. The top of the O-ring and the upper slit structure 2-3-1 form a slit area with the narrowest gap. The wide acceleration zone 2-5-3 is adjacent to the dust adsorption zone 2-5-2. The slit widens, causing the pressure in the area to drop sharply and the wind speed to increase sharply. The bottom of the slit in this wide acceleration zone is shaped like a boat with both ends curving upwards. One end of the boat shape connects to the dust adsorption area, and the other end matches the tongue shape of the upper layer 2-3-1 of the slit structure, forming a vertical atmospheric channel at the "stern". After the air enters the "boat-shaped" area from the dust adsorption area, it generates an upward vortex airflow. The vortex airflow then flows out from the vertical atmospheric channel at the "stern" and is sprayed vertically onto the inner conductor 2-1 of the wind knife structure. The inner conductor 2-1 of the wind knife structure and the inner conductor 1-1-1 of the coupling window cool the ceramic plate 1-4 connected to the inner conductor 1-1-1 of the coupling window.

[0055] like Figure 2 , Figure 5 As shown, the two sets of conductor choke units of unequal length refer to the following: with ceramic sheet 1-4 as the boundary, the outer conductor choke unit and the inner conductor choke unit on the vacuum side of ceramic sheet 1-4 form one set; the outer conductor choke unit and the inner conductor choke unit on the atmospheric side of ceramic sheet 1-4 form another set. The unequal length means that the conductor choke unit on the inner conductor of each set of conductor choke units is not the same length as the conductor choke unit on the outer conductor, but the outer conductor choke units on both sides of ceramic sheet 1-4 are the same length, and the inner conductor choke units are the same length.

[0056] Furthermore, the length of the conductor choke unit on one side of the outer conductor is relatively long at 6 mm, while the length on the other side of the inner conductor is relatively short at 4.49 mm.

[0057] like Figure 2 , Figure 5As shown, the cylindrical high-frequency coupling window 1 is equivalent to a capacitor C2 located between the inner conductor 1-1-1 and the outer conductor 1-1-2 of the coupling window, and the cylindrical air knife structure 2 is equivalent to a capacitor C1 located between the inner conductor 2-1 and the outer conductor 2-2 of the air knife. After adding the air knife structure 2, it is equivalent to connecting a capacitor C1 in parallel after the capacitor C2 corresponding to the cylindrical high-frequency coupling window 1. The capacitor C1 and the first set of conductor choke units L1 and L3 form the first filter circuit; the capacitor C2 and the second set of conductor choke units L2 and L4 form the second filter circuit.

[0058] 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 high-frequency coupling window based on internal cooling for a high-power cyclotron accelerator, characterized in that: A wind knife structure (2) is provided at the atmospheric end of the high-frequency coupling window based on internal cooling; two sets of conductor choke units of unequal length are provided on the outer conductor and inner conductor on both sides of the ceramic sheet (1-4) based on internal cooling, and the two sets of inner conductor choke units (1-2) of unequal length are equivalent to two sets of inductors, which are used to form a dual filter circuit of the high-frequency coupling window; a ceramic coating (1-3) is provided on one side of the ceramic sheet (1-4) based on internal cooling. The air knife structure (2) increases the air velocity on the surface of the ceramic sheet by compressing air to remove more heat from the surface of the ceramic sheet; and together with the conductor choke unit, it forms a filter circuit at the atmospheric end of the high-frequency coupling window, which further reduces the power heat absorbed by the ceramic sheet (1-4) of the high-frequency coupling window through the filter circuit at the atmospheric end. The ceramic coating (1-3) is a ceramic coating of a set thickness. The ceramic coating (1-3) of the set thickness can protect the ceramic from electron bombardment and accept as little high power as possible, thereby further reducing the power heat absorbed by the high frequency coupling window ceramic sheet (1-4).

2. The high-frequency coupling window based on internal cooling for a high-power cyclotron accelerator according to claim 1, characterized in that: The internally cooled high-frequency coupling window includes: a cylindrical high-frequency coupling window (1), an inner conductor (1-1-1) and an outer conductor (1-1-2) arranged along the axial direction of the cylindrical high-frequency coupling window, with the outer conductor (1-1-2) surrounding the inner conductor (1-1-1); a ceramic plate (1-4) traversing and perpendicular to the inner conductor (1-1-1) and the outer conductor (1-1-2); one side of the ceramic plate (1-4) is a vacuum cavity, and the other side is an atmospheric cavity; a cylindrical air knife structure (2) is connected to the outer end face of the atmospheric cavity, the air knife structure (2) including an inner conductor (2-1), an outer conductor (2-2), and an air knife slit structure (2-3) arranged between the inner conductor (2-1) and the outer conductor (2-2). The air knife slit structure (2-3) is welded to the inner surface of the air knife outer conductor (2-2); the air knife inner conductor (2-1) and the coupling window inner conductor (1-1-1) have the same diameter and are connected, the air knife outer conductor (2-2) and the coupling window outer conductor (1-1-2) have the same diameter and are connected; the atmosphere enters from the air knife inlet (2-4), passes through the gap of the air knife slit structure (2-3) to the air knife inner conductor (2-1) and the coupling window inner conductor (1-1-1), then from the coupling window inner conductor (1-1-1) to the ceramic plate (1-4), from the ceramic plate (1-4) to the coupling window outlet (1-5), and finally exhausts the hot air, thus forming a heat dissipation channel from the air knife inlet (2-4) to the coupling window outlet (1-5) specifically for dissipating heat from the ceramic plate (1-4).

3. The high-frequency coupling window based on internal cooling for a high-power cyclotron accelerator according to claim 1, characterized in that: The ceramic coating (1-3) of the specified thickness is arranged on the side of the ceramic sheet (1-4) facing the vacuum cavity. The ceramic coating (1-3) is a TiN coating with a thickness of no more than 6 mm. The TiN coating with a thickness of no more than 6 mm can protect the air outlet (1-5) of the coupling window from electron bombardment and can accept as little high power as possible, thereby further reducing the power heat absorbed by the ceramic sheet (1-4) of the high-frequency coupling window.

4. The high-frequency coupling window based on internal cooling for a high-power cyclotron accelerator according to claim 1, characterized in that: The air knife structure (2) is made of Teflon material and is connected to the atmospheric end of the high-frequency coupling window by means of screws through a flange structure, so as to directly cool the ceramic plate structure of the coupling window.

5. A high-frequency coupling window based on internal cooling for a high-power cyclotron accelerator according to claim 2, characterized in that: The air knife slit structure (2-3) consists of an upper slit structure (2-3-1) and a lower slit structure (2-3-2). The upper slit structure (2-3-1) and the lower slit structure (2-3-2) form a low-speed narrow zone (2-5-1), a dust adsorption zone (2-5-2), and a wide acceleration zone (2-5-3) from the outside in. The low-speed narrow zone (2-5-1) has a relatively narrow gap with relatively high pressure and relatively low wind speed. The dust adsorption zone (2-5-2) has a downwardly recessed O-ring groove, which is used to install O-rings to block dust. The top of the O-ring and the upper slit structure (2-3-1) form a slit area with the narrowest gap. The wide acceleration zone (2-5-3) is adjacent to the dust adsorption zone. -3) The gap widens from narrow to wide, causing the pressure in the area to drop sharply and the wind speed to increase sharply. The bottom shape of the gap in the wide acceleration zone (2-5-3) is a "boat" shape with both ends curving upward. One end of the "boat" shape is connected to the dust adsorption area, and the other end is matched with the tongue shape of the upper layer of the slit structure (2-3-1), forming a vertical atmospheric channel at the "stern". After the air enters the "boat" shape area from the dust adsorption area, it generates an upward vortex airflow. The vortex airflow then flows out from the vertical atmospheric channel at the "stern" and is vertically sprayed onto the inner conductor (2-1) of the wind knife structure. It also cools the ceramic plate (1-4) connected to the inner conductor (1-1-1) of the coupling window through the inner conductor (2-1) of the wind knife structure and the inner conductor (1-1-1) of the coupling window.

6. The high-frequency coupling window based on internal cooling for a high-power cyclotron accelerator according to claim 1, characterized in that: The two sets of conductor choke units of unequal length refer to the following: with the ceramic sheet (1-4) as the boundary, the outer conductor choke unit and the inner conductor choke unit on the vacuum side of the ceramic sheet (1-4) form one set; the outer conductor choke unit and the inner conductor choke unit on the atmospheric side of the ceramic sheet (1-4) form another set. The unequal length means that the conductor choke unit on the inner conductor of each set of conductor choke units has a different length than the conductor choke unit on the outer conductor, but the outer conductor choke units on both sides of the ceramic sheet (1-4) have the same length, and the inner conductor choke units have the same length.

7. The high-frequency coupling window based on internal cooling for a high-power cyclotron accelerator according to claim 6, characterized in that: The conductor choke unit is 6 mm long on one side of the outer conductor and 4.49 mm long on the other side of the inner conductor.

8. The high-frequency coupling window based on internal cooling for a high-power cyclotron accelerator according to claim 2, characterized in that: The cylindrical high-frequency coupling window (1) is equivalent to a capacitor C2 located between the inner conductor (1-1-1) and the outer conductor (1-1-2) of the coupling window, and the cylindrical air knife structure (2) is equivalent to a capacitor C1 located between the inner conductor (2-1) and the outer conductor (2-2) of the air knife. After adding the air knife structure (2), it is equivalent to connecting a capacitor C1 in parallel after the capacitor C2 corresponding to the cylindrical high-frequency coupling window (1). The capacitor C1 and the first set of conductor choke units L1 and L3 form the first filter circuit; the capacitor C2 and the second set of conductor choke units L2 and L4 form the second filter circuit.

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