A beam extraction window of a superconducting heavy ion rack and its quick-change device

Abstract

This disclosure relates to a beam extraction window for a superconducting heavy ion gantry, comprising a pressure-bearing flange, a sealing plate, and a window membrane located between the pressure-bearing flange and the sealing plate. A beam window for the heavy ion beam to pass through is opened in the center of the pressure-bearing flange. An annular pressure frame is provided on the side of the pressure-bearing flange near the sealing plate. Multiple spokes arranged in a ring are spaced apart on the inner side of the annular pressure frame. The free ends of all spokes extend towards the center of the annular pressure frame and are located outside the boundary of the beam window. The window membrane is laid on the upper surface of the multiple spokes and covers the beam window. The sealing plate is pressed and fixed to the outer edge of the window membrane to pre-tension and fix the window membrane, so that the window membrane forms an unobstructed beam channel in the beam window area. The beam extraction window and its quick-change device of this superconducting heavy ion gantry can ensure uniform heavy ion beam output dose and regular beam field morphology, improving beam utilization efficiency.

Description

Technical Field

[0001] This disclosure relates to the field of heavy ion therapy technology, specifically to a beam extraction window of a superconducting heavy ion rack and a quick-change device thereof. Background Technology

[0002] Heavy ion accelerators offer advantages such as high precision in tumor treatment, minimal damage to normal tissues, and high cure rates, making them a high-end core equipment in the field of radiotherapy. A heavy ion therapy device mainly consists of an ion implanter, a main accelerator, a beam transmission line, and a treatment terminal gantry. The treatment terminal gantry, as the core treatment terminal, typically achieves 360° omnidirectional beam output, enabling irradiation of tumor lesions from any angle. This significantly improves the adaptability and precision of tumor treatment and is a key structural component of heavy ion precision radiotherapy equipment.

[0003] The beam exit window, located at the beam terminal outlet of the treatment terminal rack, is a core component of the heavy ion therapy equipment. Its primary function is to isolate the ultra-high vacuum chamber inside the accelerator from the external atmospheric environment, maintaining the ultra-high vacuum operating conditions of the equipment's beam pipeline, while ensuring that the accelerated heavy ion beam can exit the equipment to complete the treatment. Because the equipment operates in an ultra-high vacuum environment while the external environment is at normal atmospheric pressure, the thin film of the beam exit window must withstand a stable pressure difference over a long period, while continuously receiving high-energy heavy ion beam irradiation and alternating thermal shocks. Therefore, it places extremely high demands on structural stability, fatigue resistance, and beam permeability.

[0004] In existing technologies, to improve the pressure resistance of thin-film beam extraction windows, a common approach is to install a metal grid or supporting rib structure on the back side of the window membrane. This limits the deformation of the membrane under pressure differential by reducing the free span of the window membrane. However, in traditional full-coverage cross-grid structures, some metal grids are located within the effective beam channel. When the beam passes through the extraction window, it inevitably interacts with the metal support, resulting in beam interception, multiple scattering, energy loss, and secondary particle effects. This leads to reduced beam transmittance, distortion of the dose distribution in the radiation field, and decreased beam uniformity, which is particularly detrimental to the high-precision transport and dose control of high-energy heavy ion beams in therapeutic scenarios. Summary of the Invention

[0005] The purpose of this disclosure is to provide a beam extraction window for a superconducting heavy ion gantry and a quick-change device thereof. The beam extraction window and quick-change device of the superconducting heavy ion gantry can ensure uniform output dose and regular field shape of heavy ion beam, and improve beam utilization efficiency.

[0006] To achieve the above objectives, this disclosure provides a beam exit window for a superconducting heavy ion rack, including a pressure-bearing flange, a sealing plate, and a window membrane located between the pressure-bearing flange and the sealing plate. The pressure-bearing flange has a beam window in its center for the heavy ion beam to pass through. An annular pressure-bearing frame is provided on the side of the pressure-bearing flange near the sealing plate. Multiple spokes arranged in a ring are spaced apart on the inner side of the annular pressure-bearing frame. The free ends of all spokes extend towards the center of the annular pressure-bearing frame and are located outside the boundary of the beam window. The window membrane is laid on the upper surface of the multiple spokes and covers the beam window. The sealing plate is pressed and fixed to the outer edge of the window membrane to pre-tension and fix the window membrane, so that the window membrane forms an unobstructed beam channel in the beam window area.

[0007] Optionally, the spokes are constructed with a gradually varying thickness, and the thickness of the end of the spoke connected to the annular bearing frame is greater than the thickness of the free end of the spoke.

[0008] Optionally, the pressure-bearing flange has a groove on the side near the sealing plate, the annular pressure-bearing frame is disposed in the groove, and the outer edge of the window film at least partially overlaps the annular pressure-bearing frame.

[0009] Optionally, the outer edge of the annular pressure-bearing frame is provided with a plurality of telescopic clamping assemblies arranged around the window film. The telescopic clamping assembly includes an elastic element and an elastic clamp. The elastic element is fixed to the outer edge of the annular pressure-bearing frame, and the elastic clamp is slidably disposed on the annular pressure-bearing frame in the radial direction. The clamping end of the elastic clamp is used to clamp and fix the window film, and the other end of the elastic clamp is connected to the elastic element to apply an outward pretension force to the window film. The telescopic clamping assembly is located inside the groove.

[0010] Optionally, the window film is located inside the groove, the sealing plate includes a plate body and an annular boss disposed near the center of the plate body, the telescopic clamping assembly is located outside the annular boss, the annular boss is pressed and fixed to the outer edge of the window film, and the outer edge of the plate body is sealed to the pressure-bearing flange.

[0011] Optionally, the outer edge of the annular pressure-bearing frame is provided with multiple sliding grooves, the sliding grooves are staggered with the spokes, the elastic clip is slidably connected to the sliding grooves, and the elastic element is provided in the sliding grooves and located on the side of the elastic clip away from the window film.

[0012] Based on the above technical solutions, this application also provides a quick replacement device for the beam extraction window of a superconducting heavy ion gantry, including an installation device and the beam extraction window of the superconducting heavy ion gantry. The installation device includes a sealing gasket and a chain clamp. The pressure-bearing flange and the pressure plate of the sealing plate each include a first cylindrical section, a tapered transition section, and a second cylindrical section connected sequentially along the axial direction. The diameter of the first cylindrical section is larger than the diameter of the second cylindrical section. The first cylindrical section of the pressure-bearing flange is fitted with the first cylindrical section of the sealing plate, and the sealing gasket abuts against the mating surfaces of the two first cylindrical sections. The tapered transition section of the pressure-bearing flange, the tapered transition section of the sealing plate, and the two mating surfaces of the sealing plate abut against each other. The outer circular surfaces of the first cylindrical segment together form a trapezoidal annular protrusion; the chain clamp includes multiple chain blocks and two chains located on both sides of the chain blocks, each chain including a chain plate and a connecting shaft; the corresponding sides of two adjacent chain blocks are hinged through the chain plate and the connecting shaft to connect multiple chain blocks in series; the two chain blocks at both ends are fixed together by bolts to form a flexible ring structure; each chain block has a trapezoidal notch on its inner side, and the trapezoidal notches of all the chain blocks together form an annular groove that fits the annular protrusion; the chain clamp is clamped to the outside of the pressure flange and the sealing plate through the annular groove to detachably seal the pressure flange and the sealing plate.

[0013] Optionally, the taper of the trapezoidal notch and the taper of the annular protrusion are both 18° to 20°.

[0014] Through the above technical solution, the beam exit window of the superconducting heavy ion rack of this application includes a pressure-bearing flange, a sealing plate, and a window membrane disposed between the pressure-bearing flange and the sealing plate. A beam window is opened in the middle of the pressure-bearing flange, providing a dedicated exit channel for the high-energy heavy ion beam. An annular pressure-bearing frame is provided on the end face of the pressure-bearing flange near the sealing plate. Multiple spokes arranged in a ring are distributed at intervals on the inner side of the annular pressure-bearing frame. The free ends of all spokes extend towards the center of the annular pressure-bearing frame, and the endpoints of the free ends of all spokes are located outside the boundary of the beam window, ensuring that the entire spoke completely avoids the effective beam transmission area. The window membrane is laid on the upper surface of the multiple spokes and covers the entire beam window. The system achieves vacuum isolation and sealing in the core beam transmission area. A sealing plate is pressed and fixed to the outer edge of the window film. A pre-tensioning force is applied to the window film through axial pressing assembly, achieving pre-tensioning and fixing of the window film. Ultimately, a pure hollow beam channel without obstruction or interference from metal structures is formed in the core beam transmission area of ​​the beam window. In this way, compared with the traditional metal grid method, this application avoids the scattering, diffraction, and energy loss problems caused by high-energy heavy ion beams penetrating metal grids, ensuring uniform heavy ion beam output dose and regular field morphology, accurately matching the irradiation needs of tumor lesions, significantly improving the accuracy of tumor radiotherapy, and significantly improving the effective utilization rate of the beam while reducing equipment energy consumption.

[0015] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the beam extraction window of the superconducting heavy ion rack provided in the embodiments of this disclosure;

[0017] Figure 2 yes Figure 1 A magnified view of a section at point A in the middle; Figure 3 This is another schematic diagram of the beam extraction window of the superconducting heavy ion rack provided in the embodiments of this disclosure; Figure 4 yes Figure 3 A magnified view of a section at point B in the middle; Figure 5 This is a schematic diagram of the structure of a quick-change device for the beam extraction window of a superconducting heavy ion rack provided in an embodiment of this disclosure; Figure 6 This is another schematic diagram of the quick-change device for the beam extraction window of the superconducting heavy ion rack provided in the embodiments of this disclosure.

[0018] Explanation of reference numerals in the attached drawings: 10, pressure flange; 11, beam window; 12, groove; 13, first cylindrical section; 14, tapered transition section; 15, second cylindrical section; 20, sealing plate; 21, plate body; 22, annular boss; 30, window film; 40, annular pressure frame; 41, slide groove; 50, spoke; 60, telescopic clamping assembly; 61, elastic element; 62, elastic clamp; 70, mounting device; 71, sealing gasket; 72, chain clamp; 721, chain block; 7211, annular groove; 722, chain; 7221, chain plate; 7222, connecting shaft. Detailed Implementation

[0019] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0020] In this disclosure, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the relative positions of the corresponding components in the direction of gravity when they are in use, and "inner" and "outer" refer to their relative positions to the contours of the corresponding components themselves. Furthermore, the terms "first," "second," etc., used in this disclosure are for distinguishing one element from another and do not have sequential or importance implications. In the following description, when referring to the accompanying drawings, unless otherwise explained, the same reference numerals in different drawings denote the same or similar elements. The above definitions are for explanation and illustration only and should not be construed as limiting this disclosure.

[0021] According to exemplary embodiments of this disclosure, reference is made to Figures 1 to 4 As shown, a beam exit window for a superconducting heavy ion generator is provided, including a pressure-bearing flange 10, a sealing plate 20, and a window membrane 30 located between the pressure-bearing flange 10 and the sealing plate 20. A beam window 11 for the heavy ion beam to pass through is opened in the middle of the pressure-bearing flange 10. An annular pressure frame 40 is provided on the side of the pressure-bearing flange 10 near the sealing plate 20. Multiple spokes 50 are arranged in a ring on the inner side of the annular pressure frame 40. The free ends of all spokes 50 extend toward the center of the annular pressure frame 40 and are located outside the boundary of the beam window 11. The window membrane 30 is laid on the upper surface of the multiple spokes 50 and covers the beam window 11. The sealing plate 20 is pressed and fixed to the outer edge of the window membrane 30 to pre-tension and fix the window membrane 30, so that the window membrane 30 forms an unobstructed beam channel in the beam window 11 area.

[0022] Through the above technical solution, the beam exit window of the superconducting heavy ion rack of this application includes a pressure-bearing flange 10, a sealing plate 20, and a window membrane 30 disposed between the pressure-bearing flange 10 and the sealing plate 20. A beam window 11 is opened in the middle of the pressure-bearing flange 10 to provide a dedicated exit channel for the high-energy heavy ion beam. An annular pressure-bearing frame 40 is provided on the end face of the pressure-bearing flange 10 near the sealing plate 20. Multiple spokes 50 arranged in a ring are distributed at intervals on the inner side of the annular pressure-bearing frame 40. The free ends of all spokes 50 extend toward the center of the annular pressure-bearing frame 40, and the endpoints of the free ends of all spokes 50 are located outside the boundary of the beam window 11, ensuring that the spokes 50 completely avoid the effective beam transmission area. The window membrane 30 is laid on the multiple spokes 50. The upper surface covers the entire area of ​​the beam window 11, achieving a vacuum isolation and sealing function. The sealing plate 20 is pressed and fixed to the outer edge area of ​​the window membrane 30. The window membrane 30 is pre-tensioned and fixed by applying a pre-tightening force through an axial pressing assembly method. Finally, a pure hollow beam channel without obstruction and without metal structure interference is formed in the core beam transmission area of ​​the beam window 11. In this way, compared with the traditional metal grid method, this application avoids the scattering, diffraction and energy loss problems caused by the high-energy heavy ion beam penetrating the metal grid, ensuring uniform output dose and regular field shape of the heavy ion beam, accurately matching the irradiation needs of tumor lesions, greatly improving the accuracy of tumor radiotherapy, and significantly improving the effective utilization rate of the beam and reducing equipment energy consumption.

[0023] This application uses an annular bearing frame 40 in conjunction with annularly arranged spokes 50 to form a uniform and stable rigid support for the window film 30 as a whole, effectively offsetting the load impact caused by the pressure difference between the inside and outside of the equipment, limiting the deformation and bulging of the window film 30 under alternating ultra-high vacuum and normal pressure conditions, and ensuring the structural stability and fatigue resistance of the window film 30 during long-term operation.

[0024] In addition, this application achieves pre-tensioning and fixing by pressing the outer edge of the window film 30 with the sealing pressure plate 20, so that the window film 30 always remains flat and taut in the working state, avoiding the window film 30 from loosening and wrinkling, effectively improving the window film 30's ability to resist alternating hot and cold shocks and high-energy beam irradiation fatigue, reducing the probability of aging and damage of the window film 30, and extending the service life of the window film 30.

[0025] According to exemplary embodiments of this disclosure, referring to Figure 1 and Figure 2As shown, the spokes 50 can be constructed with a gradually varying thickness, and the thickness of the end of the spoke 50 connected to the annular pressure frame 40 is greater than the thickness of the free end of the spoke 50. With this configuration, the thicker root of the spoke 50 bears the pressure differential load of the window film 30 and the beam impact load, significantly improving the structural strength and bending and torsional resistance of the root of the spoke 50. The free end of the spoke 50 is located at the boundary of the beam window 11 and adopts a thin, gradually varying structure, which minimizes the structural volume and obstruction area at the end of the spoke 50, further reducing the micro-scattering and interference of the metal structure on the beam edge, and optimizing beam uniformity and field accuracy.

[0026] According to exemplary embodiments of this disclosure, such as Figure 1 and Figure 2 As shown, a groove 12 is provided on the side of the pressure flange 10 near the sealing plate 20. The annular pressure support frame 40 is disposed in the groove 12, and the outer edge of the window film 30 at least partially overlaps the annular pressure support frame 40. The annular pressure support frame 40 is installed entirely inside the groove 12, and the outer edge area of ​​the window film 30 at least partially overlaps the upper end face of the annular pressure support frame 40, realizing embedded assembly positioning. This ensures that the window film 30 is laid flat and fits tightly, eliminates assembly gaps, effectively improves the overall sealing performance of the device, and stably maintains the ultra-high vacuum condition inside the accelerator. At the same time, it ensures the accuracy and symmetry of the annular arrangement of the multiple spokes 50, ensuring that the window film 30 is subjected to uniform force and balanced support. In addition, the embedded groove 12 assembly structure allows the annular pressure support frame 40 to be housed inside the pressure flange 10, reducing the axial space occupied by the overall structure and making the overall structure more compact.

[0027] According to exemplary embodiments of this disclosure, referring to Figure 3 and Figure 4 As shown, the outer edge of the annular pressure frame 40 can be provided with multiple telescopic clamping assemblies 60 arranged around the window film 30. Each telescopic clamping assembly 60 includes an elastic element 61 and an elastic clamp 62. The elastic element 61 is fixed to the outer edge of the annular pressure frame 40, and the elastic clamp 62 slides radially on the annular pressure frame 40. The clamping end of the elastic clamp 62 is used to clamp and fix the window film 30, and the other end of the elastic clamp 62 is connected to the elastic element 61 to apply an outward pretension force to the window film 30. The telescopic clamping assembly 60 is located inside the groove 12. Through the elastic structure of the telescopic clamping assembly 60, a uniform radial outward pretension force can be continuously applied to the window film 30. Regardless of the equipment's alternating hot and cold operating conditions or long-term fatigue deformation, the window film 30 can always be kept in a flat and taut state, preventing the window film 30 from loosening, wrinkling, or partially collapsing, thus ensuring the flatness of the beam transmission surface.

[0028] In the above technical solution, the elastic element 61 can be a tension spring or an elastic cord, which can house all the telescopic clamping components 60 inside the groove 12, completely avoiding the effective working area of ​​the beam window 11, and will not cause any obstruction or scattering interference to the heavy ion beam transmission.

[0029] According to exemplary embodiments of this disclosure, such as Figures 1 to 4 As shown, the window membrane 30 is located inside the groove 12. The sealing plate 20 includes a plate body 21 and an annular boss 22 located near the center of the plate body 21. The telescopic clamping assembly 60 is located outside the annular boss 22. The annular boss 22 is pressed and fixed to the outer edge of the window membrane 30. The outer edge of the plate body 21 is sealed to the pressure flange 10. By individually pressing the outer edge of the window membrane 30 with the annular boss 22, the pressing area of ​​the window membrane 30 can be precisely controlled, avoiding the large-area pressing of the plate body 21 from causing squeezing or interference to the telescopic clamping assembly 60. The outer edge of the plate body 21 and the pressure flange 10 achieve an external seal, and the annular boss 22 and the window membrane 30 achieve an inner seal, forming a double-layer sealing protection structure. This effectively prevents external atmosphere from entering the vacuum chamber of the equipment, stably maintains the ultra-high vacuum operation of the equipment, and ensures the stability of beam transmission.

[0030] According to exemplary embodiments of this disclosure, such as Figure 3 and Figure 4 As shown, the outer edge of the annular pressure-bearing frame 40 can be provided with multiple sliding grooves 41. The sliding grooves 41 are staggered with the spokes 50, and the elastic clip 62 is slidably connected to the sliding grooves 41. The elastic element 61 is located in the sliding grooves 41 and is located on the side of the elastic clip 62 away from the window film 30. In the above technical solution, the sliding grooves 41 and spokes 50 are staggered to make full use of the annular space of the annular pressure-bearing frame 40, while not affecting each other's functional operation. The spokes 50 support the window film 30, and the telescopic clamping assembly 60 adaptively tensions the window film 30. The sliding grooves 41 can precisely limit the sliding trajectory of the elastic clip 62, ensuring that the elastic clip 62 slides smoothly only in the radial direction, avoiding deviation and jamming, and ensuring uniform and stable pre-tension force.

[0031] Based on the above technical solutions, such as Figures 1 to 6As shown, this application also provides a quick replacement device for the beam extraction window of a superconducting heavy ion rack, including a beam extraction window of the superconducting heavy ion rack with an installation device 70 or more. The installation device 70 includes a sealing gasket 71 and a chain clamp 72. The pressure flange 10 and the pressure plate body 21 of the sealing plate 20 both include a first cylindrical section 13, a conical transition section 14 and a second cylindrical section 15 connected sequentially along the axial direction. The diameter of the first cylindrical section 13 is larger than the diameter of the second cylindrical section 15. The first cylindrical section 13 of the pressure flange 10 is fitted with the first cylindrical section 13 of the sealing plate 20, and the sealing gasket 71 abuts against the mating surfaces of the two first cylindrical sections 13. The conical transition section 14 of the pressure flange 10, the conical transition section 14 of the sealing plate 20 and the outer circular surfaces of the two mating first cylindrical sections 13 together form an annular protrusion with a trapezoidal cross-section.

[0032] The chain clamp 72 includes multiple chain blocks 721 and two chains 722 located on both sides of the chain blocks 721. Each chain 722 includes a chain plate 7221 and a connecting shaft 7222. The corresponding sides of two adjacent chain blocks 721 are hinged through the chain plate 7221 and the connecting shaft 7222 to connect multiple chain blocks 721 in series. The two chain blocks 721 at both ends are fixed together by bolts to form a flexible ring structure. Each chain block 721 has a trapezoidal notch on its inner side. The trapezoidal notches of all chain blocks 721 together form an annular groove 7211 that matches the annular protrusion. The chain clamp 72 is clamped to the outside of the pressure flange 10 and the sealing plate 20 through the annular groove 7211 to detachably seal the pressure flange 10 and the sealing plate 20.

[0033] In the above technical solution, the pressure plate bodies 21 of the pressure flange 10 and the sealing plate 20 are both composed of a first cylindrical section 13, a tapered transition section 14, and a second cylindrical section 15 connected sequentially along the axial direction, and the diameter of the first cylindrical section 13 is larger than the diameter of the second cylindrical section 15; the end faces of the pressure flange 10 and the first cylindrical section 13 of the sealing plate 20 are fitted together, and a sealing gasket 71 is sandwiched between the two mating surfaces to achieve end face sealing; at the same time, the tapered transition section 14 of the pressure flange 10, the tapered transition section 14 of the sealing plate 20, and the outer circular surfaces of the two mating first cylindrical sections 13 together form an annular protrusion structure with a trapezoidal cross-section; the chain clamp 72 is flexible. The disassembled clamp structure consists of multiple chain blocks 721 and chains 722 on both sides. Each chain 722 is composed of a chain plate 7221 and a connecting shaft 7222. Adjacent chain blocks 721 are connected in series by hinges through the chain plate 7221 and the connecting shaft 7222. The chain blocks 721 at both ends are fixed by bolts, forming a complete flexible ring. Each chain block 721 has a trapezoidal notch on its inner side. All trapezoidal notches are connected to form an annular groove 7211 that matches the annular protrusion. The chain clamp 72 clamps the pressure flange 10 and the sealing plate 20 on the outside of the pressure flange 10 and the sealing plate 20 through the annular groove 7211, realizing a detachable and sealed fixed connection between the pressure flange 10 and the sealing plate 20.

[0034] With the above settings, the chain clamp 72 can be quickly opened and closed by simply removing and installing the end fixing bolts, which can quickly complete the disassembly, replacement and installation of the beam outlet window; the trapezoidal annular protrusion and the annular groove 7211 are compatible, which has a good centering and locking effect. The chain clamp 72 can achieve automatic centering and alignment during the clamping process, ensuring that the pressure flange 10 and the sealing pressure plate 20 are subjected to uniform force in the circumference and fit tightly. With the sealing gasket 71 on the mating surface, a uniform seal in all directions is achieved.

[0035] According to exemplary embodiments of this disclosure, please refer to Figure 6 As shown, the taper of both the trapezoidal notch and the annular protrusion is 18° to 20°. This taper range ensures excellent guiding and alignment of the trapezoidal structure, facilitating quick assembly of the chain clamp 72 and reducing installation difficulty. It also avoids insufficient locking force and clamp loosening due to excessive taper, or assembly / disassembly jamming and self-locking jamming due to insufficient taper, ensuring a flexible and reliable locking structure with sufficient locking force. For example, the taper of both the trapezoidal notch and the annular protrusion can be set to 18°, 19°, or 20° to allow for better contact between the chain clamp 72 and the annular protrusion, resulting in a more even distribution of the locking load.

[0036] In summary, this application employs an annular pressure frame 40 in conjunction with annularly arranged spokes 50. The spokes 50 avoid the effective area of ​​the beam window 11, ensuring the core beam channel is free from metal obstruction and structural interference. This eliminates the scattering, diffraction, and energy loss problems of heavy ion beams at their source, effectively improving the drawbacks of field dose distortion and poor beam uniformity. It ensures a regular field shape and uniform dose output, enhancing the precision of tumor radiotherapy while simultaneously increasing beam utilization and reducing equipment energy consumption. Furthermore, the use of spokes 50 with gradually varying thickness further reduces the slight interference of boundary metal on the beam edge, effectively optimizing beam transmission quality and field shaping accuracy. Simultaneously, the annular pressure frame 40, in conjunction with multiple spokes 50, provides uniform rigid support for the window membrane 30, effectively offsetting the pressure difference load inside and outside the equipment, suppressing deformation, bulging, and collapse of the window membrane 30, and adapting to extreme operating conditions of long-term ultra-high vacuum and alternating atmospheric pressure.

[0037] In addition, this application is equipped with a quick replacement device. The pressure flange 10 and the sealing plate 20 form a trapezoidal annular protrusion, which is matched with the annular groove 7211 of the flexible chain clamp 72 to form a matching clamping structure. Compared with the traditional multi-bolt locking method, this application only needs to remove and install the fixing bolts at both ends to realize the quick opening and closing of the clamp. It can efficiently complete the disassembly, replacement, and reassembly of the beam exit window, greatly shorten the equipment downtime for maintenance, and improve the start-up utilization rate of radiotherapy equipment.

[0038] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0039] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0040] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A beam extraction window for a superconducting heavy ion rack, comprising a pressure-bearing flange, a sealing plate, and a window membrane located between the pressure-bearing flange and the sealing plate, characterized in that, The pressure-bearing flange has a beam window in the middle for the heavy ion beam to pass through. The pressure-bearing flange has an annular pressure frame on the side near the sealing plate. Multiple spokes are arranged in a ring on the inner side of the annular pressure frame. The free ends of all the spokes extend toward the center of the annular pressure frame and are located outside the boundary of the beam window. The window film is laid on the upper surface of the multiple spokes and covers the beam window. The sealing plate is pressed and fixed to the outer edge of the window film to pre-tension and fix the window film, so that the window film forms an unobstructed beam channel in the beam window area.

2. The beam extraction window of the superconducting heavy ion rack according to claim 1, characterized in that, The spokes are constructed with a gradually varying thickness, and the thickness of the end of the spoke connected to the annular bearing frame is greater than the thickness of the free end of the spoke.

3. The beam extraction window of the superconducting heavy ion rack according to claim 1 or 2, characterized in that, The pressure-bearing flange has a groove on the side near the sealing plate, the annular pressure-bearing frame is disposed in the groove, and the outer edge of the window film at least partially overlaps the annular pressure-bearing frame.

4. The beam extraction window of the superconducting heavy ion rack according to claim 3, characterized in that, The outer edge of the annular pressure-bearing frame is provided with a plurality of telescopic clamping assemblies arranged around the window film. Each telescopic clamping assembly includes an elastic element and an elastic clamp. The elastic element is fixed to the outer edge of the annular pressure-bearing frame, and the elastic clamp is slidably disposed on the annular pressure-bearing frame in the radial direction. The clamping end of the elastic clamp is used to clamp and fix the window film, and the other end of the elastic clamp is connected to the elastic element to apply an outward pretension force to the window film. The telescopic clamping assembly is located inside the groove.

5. The beam extraction window of the superconducting heavy ion rack according to claim 4, characterized in that, The window film is located inside the groove. The sealing plate includes a plate body and an annular boss located near the center of the plate body. The telescopic clamping assembly is located outside the annular boss. The annular boss is pressed and fixed to the outer edge of the window film. The outer edge of the plate body is sealed to the pressure-bearing flange.

6. The beam extraction window of the superconducting heavy ion rack according to claim 4, characterized in that, The outer edge of the annular pressure-bearing frame is provided with multiple sliding grooves, which are staggered with the spokes. The elastic clip is slidably connected to the sliding grooves. The elastic element is located in the sliding grooves and is located on the side of the elastic clip away from the window film.

7. A quick-change device for the beam extraction window of a superconducting heavy ion rack, characterized in that, The assembly includes an installation device and a beam extraction window of the superconducting heavy ion rack as described in any one of claims 1 to 6, wherein the installation device includes a sealing gasket and a chain clamp. The pressure-bearing flange and the pressure plate body of the sealing plate both include a first cylindrical section, a tapered transition section and a second cylindrical section connected sequentially along the axial direction, wherein the diameter of the first cylindrical section is larger than the diameter of the second cylindrical section; The first cylindrical section of the pressure-bearing flange is fitted with the first cylindrical section of the sealing plate, and the sealing gasket abuts against the mating surfaces of the two first cylindrical sections; wherein, the tapered transition section of the pressure-bearing flange, the tapered transition section of the sealing plate, and the outer circular surfaces of the two mating first cylindrical sections together form an annular protrusion with a trapezoidal cross-section. The chain clamp includes multiple chain blocks and two chains on both sides of the chain blocks. Each chain includes a chain plate and a connecting shaft. The corresponding sides of two adjacent chain blocks are hinged through the chain plate and the connecting shaft to connect multiple chain blocks in series. The two chain blocks at both ends are fixed together by bolts to form a flexible circular ring structure. Each chain block has a trapezoidal notch on its inner side, and the trapezoidal notches of all the chain blocks together form an annular groove that matches the annular protrusion; the chain clamp is clamped to the outside of the pressure flange and the sealing plate through the annular groove to detachably seal the pressure flange and the sealing plate.

8. The quick-change device for the beam extraction window of the superconducting heavy ion rack according to claim 7, characterized in that, The taper of the trapezoidal notch and the taper of the annular protrusion are both 18° to 20°.

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