Beam-termination membrane window and beam termination, particle accelerator

Abstract

This invention relates to the field of particle accelerator technology, and more particularly to a beam terminal membrane window, a beam terminal, and a particle accelerator. The beam terminal membrane window includes a pressure plate, a sealing plate, an isolation membrane, and a sealing protection structure. The sealing protection structure is located on the sealing plate and at the edge of the working window. The sealing protection structure includes a transition surface and at least two levels of protective recesses. The sealing protection structure is used to seal the isolation membrane between the sealing plate and the pressure plate, utilizing the various levels of protective recesses to reserve space for the recessed isolation membrane from the sealing connection surface to the vacuum environment side, forming a stepped space. The stepped space and the transition surface work together on the working window to achieve a synergistic effect of sealing and space protection. Under conditions of large scanning area and highly uniform beam passage, this beam terminal membrane window can seal and isolate the inside and outside of the accelerator device, ensuring reliable particle beam passage and effectively improving the sealing performance and safety of the accelerator device.

Description

Technical Field

[0001] This invention relates to the field of particle accelerator technology, and more particularly to a beam terminal membrane window, a beam terminal, and a particle accelerator. Background Technology

[0002] In particle accelerators, beam terminations often feature membrane windows. Their function is to isolate the main vacuum system from the atmospheric environment while allowing the particle beam to pass through. Examples include biaxially stretchable polyester film membrane windows used in carbon ion therapy devices. Currently, beam termination membrane windows are mostly made of either metals or non-metals, each with different functions. Non-metals include materials like the aforementioned polyester film. Commonly used materials for metal membrane windows include Al, Fe, and Ti. Small-sized circular metal membrane windows are currently widely used. However, for large-scanning-area, high-uniformity beams, using a circular structure for large-sized metal membrane windows would increase the overall material of the membrane and flanges, significantly increasing the window's weight and placing higher demands on the strength of the connected equipment. Summary of the Invention

[0003] This invention provides a beam terminal membrane window, a beam terminal, and a particle accelerator to address the shortcomings of existing membrane windows in the face of large scanning area and highly uniform beams, such as insufficient reliability, excessive material usage, excessive weight of the membrane window, and excessively high strength requirements for connected equipment.

[0004] This invention provides a beam terminal membrane window, comprising:

[0005] The pressure plate is located on the atmospheric environment side;

[0006] A sealing plate is disposed on the vacuum environment side, and the sealing plate is sealed to the pressure plate at the sealing connection surface;

[0007] The working window extends through the pressure plate and the sealing plate;

[0008] An isolation membrane is provided on the sealing connection surface, and the isolation membrane seals and covers the working window;

[0009] A sealing and protective structure is disposed on the sealing plate and at the edge of the working window; wherein, the sealing and protective structure includes a transition surface and at least two levels of protective recesses, each level of the protective recesses being continuously connected to the edge of the working window, and the transition surface being disposed at least on the protective recess closest to the edge of the working window;

[0010] The sealing and protective structure is used to seal the isolation membrane between the sealing plate and the pressure plate, so as to use the protective recesses of each level to reserve space for the recessed isolation membrane from the sealing connection surface to the vacuum environment side, forming a stepped space; the stepped space and the transition surface work together on the working window to achieve a synergistic effect of sealing and space protection.

[0011] According to a beam terminal membrane window provided by the present invention, the at least two-level protective recess includes a first recess and a second recess, both of which are formed on the side of the sealing plate facing the isolation membrane. The edge of the working window, the first recess, and the second recess are sequentially connected, and the depth of the first recess is greater than the depth of the second recess. The transition surface is at least disposed at the position where the first recess connects to the edge of the working window.

[0012] According to a beam terminal membrane window provided by the present invention, the sealing protection structure further includes a first sealing groove, which is formed on the sealing plate and located on the sealing connection surface; the first sealing groove is disposed around the periphery of each level of the protective recess, and the first sealing groove is spaced apart from the protective recess.

[0013] According to a beam terminal membrane window provided by the present invention, the sealing protection structure further includes a second sealing groove, the second sealing groove being disposed on the surface of the sealing plate opposite to the sealing connection surface, and the second sealing groove surrounding the periphery of the working window.

[0014] According to the present invention, a beam terminal membrane window further includes a plurality of sealing holes, each of which penetrates the pressure plate and the sealing plate; all of the sealing holes are arranged around the working window; the sealing holes are used to seal the pressure plate and the sealing plate by sealing bolts.

[0015] According to the present invention, a beam terminal membrane window further includes a plurality of connection holes, each of which passes through the pressure plate and the sealing plate. All the connection holes are arranged around the working window, and a sealing hole is provided between adjacent connection holes. The connection holes are used to connect external devices by connecting bolts.

[0016] The beam termination membrane window provided by the present invention further includes at least one of the following:

[0017] The working window is rectangular or polygonal;

[0018] The transition surface is a circular arc transition surface;

[0019] The separator is a titanium membrane.

[0020] The present invention also provides a beam terminal, including the beam terminal membrane window described above.

[0021] The present invention also provides a particle accelerator, including the above-described beam terminal membrane window; or including the above-described beam terminal.

[0022] The present invention has at least the following beneficial effects. The beam termination membrane window provided by the present invention includes a pressure plate, a sealing plate, a working window, an isolation membrane, and a sealing protection structure. The pressure plate is disposed on the atmospheric environment side. The sealing plate is disposed on the vacuum environment side. The sealing plate and the pressure plate are sealed together at a sealing connection surface. The working window extends through the pressure plate and the sealing plate. The isolation membrane is sealed together at the sealing connection surface and seals over the working window. The sealing protection structure is disposed on the sealing plate. The sealing protection structure is disposed at the edge of the working window. The sealing protection structure is used to seal the isolation membrane between the sealing plate and the pressure plate. Therefore, when facing beams with large scanning areas and high uniformity, this beam termination membrane window can seal and isolate the main vacuum system within the accelerator device from the external atmospheric environment, and can also ensure the reliable passage of the particle beam, effectively improving the sealing and safety between the internal and external environments of the accelerator device.

[0023] Furthermore, in the beam terminal membrane window of the present invention, the sealing and protective structure includes a transition surface connected to the edge of the working window. By providing a transition surface at the edge of the working window, this membrane window utilizes a smooth curved surface instead of a right-angled structure at the edge of the working window. This effectively prevents the isolation membrane from tearing when it experiences depression due to pressure differential, significantly reducing the possibility of shear damage to the portion of the isolation membrane located at the edge of the working window. This, in turn, greatly improves the operational strength, structural reliability, and safety of the beam terminal membrane window.

[0024] Furthermore, in the beam terminal membrane window of the present invention, the sealing and protection structure further includes at least two levels of protective recesses. Each level of protective recess is continuously connected to the edge of the working window, and the transition surface is provided at least on the protective recess closest to the edge of the working window. Thus, this sealing and protection structure can utilize the various levels of protective recesses to progressively reserve space for the recessed isolation membrane from the sealing connection surface to the vacuum environment side, thereby forming a stepped space. This stepped space, together with the aforementioned transition surface, acts on the working window to achieve a synergistic effect of sealing and space protection, thereby significantly improving the operational strength, structural reliability, and safety of the beam terminal membrane window.

[0025] The present invention also provides a beam terminal, including the beam terminal membrane window described above. By setting the beam terminal membrane window, the beam terminal possesses all the advantages of the beam terminal membrane window described above, which will not be elaborated here.

[0026] The present invention also provides a particle accelerator, including the aforementioned beam termination film window; or including the aforementioned beam termination. By setting the aforementioned beam termination film window, the particle accelerator possesses all the advantages of the aforementioned beam termination film window, which will not be elaborated further here. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the beam terminal membrane window provided by the present invention on the vacuum environment side.

[0029] Figure 2 yes Figure 1 The diagram shows the AA-direction structure.

[0030] Figure 3 yes Figure 2 The diagram shows a BB-oriented structural schematic.

[0031] Figure 4 This is a schematic diagram of the structure of the sealing plate provided by the present invention.

[0032] Figure 5 This is a schematic diagram of the beam terminal membrane window provided by the present invention on the atmospheric environment side.

[0033] Figure label:

[0034] 1. Pressure plate; 2. Isolation membrane; 3. Sealing plate; 4. Sealing bolt; 5. First sealing groove; 6. First recessed platform; 61. Transition surface; 7. Second recessed platform; 8. Second sealing groove; 9. Sealing hole; 10. Connecting hole; 11. Sealing connection surface. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0036] The following is combined with Figures 1 to 5 The present invention describes a beam terminal membrane window (hereinafter referred to as "membrane window"), and a beam terminal and particle accelerator provided with the membrane window.

[0037] It should be noted that the membrane window described in this embodiment of the invention is a beam terminal membrane window used in a 300MeV proton and heavy ion accelerator device. Wherein, Figure 1 This is a front view of the beam terminal membrane window described in an embodiment of the present invention, that is... Figure 1 This is a schematic diagram of the membrane window structure from the perspective of the vacuum environment inside the particle accelerator, that is, a schematic diagram of the membrane window structure on the vacuum environment side. Figure 5 This is a rear view of the beam terminal membrane window, i.e. Figure 5 This is a schematic diagram of the membrane window structure from the perspective of the atmospheric environment outside the particle accelerator, that is, a schematic diagram of the membrane window structure on the atmospheric environment side.

[0038] Figures 1 to 5 As shown, the beam terminal membrane window of this embodiment includes a pressure plate 1, a sealing plate 3, a working window, an isolation membrane 2, and a sealing protection structure. The pressure plate 1 is disposed on the atmospheric environment side. The sealing plate 3 is disposed on the vacuum environment side. The sealing plate 3 and the pressure plate 1 are sealed together at a sealing connection surface 11. The working window extends through the pressure plate 1 and the sealing plate 3. The isolation membrane 2 is sealed together at the sealing connection surface 11 and seals over the working window. The beam generated by the accelerator device passes through the vacuum beam terminal and penetrates the membrane window at the end of the beam terminal to enter the atmospheric environment; that is, the beam travels from the vacuum environment through the working window to the atmospheric environment, passing through the isolation membrane 2 during its journey. To improve sealing performance, the sealing plate 3 is provided with a sealing protection structure. The sealing protection structure is disposed at the edge of the working window. The sealing protection structure is used to seal the isolation membrane 2 between the sealing plate 3 and the pressure plate 1. The preferred sealing and protection structure is formed on the sealing plate and connected to the isolation membrane 2. The sealing and protection structure can protect the isolation membrane 2, thereby forming a synergistic effect of sealing and protection for the entire membrane window, especially improving the reliable protection and sealing of the isolation membrane 2 during operation.

[0039] Therefore, when faced with a large scanning area and highly uniform beam passage, the beam terminal membrane window can seal and isolate the main vacuum system (vacuum environment) inside the accelerator device from the external atmospheric environment, and can also ensure the reliable passage of the particle beam, effectively improving the sealing and safety between the internal and external environments of the accelerator device.

[0040] In some embodiments, such as Figures 1 to 5As shown, to ensure the effective scanning area of ​​the working window meets the requirements, it is preferable that the inner contour dimension of the sealing and protective structure is larger than the effective scanning area of ​​the working window. Preferably, the working window is rectangular or polygonal. The proton and heavy ion beam enters the atmospheric environment from the vacuum environment inside the accelerator through the working window. This embodiment of the invention uses a rectangular working window as an example to describe the membrane window structure in detail. Preferably, the working window of the membrane window is configured with an effective scanning area of ​​320mm × 320mm. Compared to a circular membrane window, a rectangular or polygonal working window can significantly reduce the external dimensions and the total weight of the membrane window while maintaining the same scanning area, thus meeting the requirements for lightweight membrane windows. For example, if a circular working window is used, the overall external dimensions of the membrane window will be much larger than a diameter of 600mm while maintaining the same effective scanning area, and the corresponding total weight will reach or even exceed 58kg; if a square working window is used, the external dimensions of the membrane window can be optimized to 430mm × 430mm while maintaining the same effective scanning area, and the weight can be reduced to 35kg, a 40% reduction compared to a circular membrane window.

[0041] In some specific embodiments, such as Figures 1 to 5 As shown, the preferred isolation membrane 2 is a titanium membrane. The titanium membrane is press-fitted into the sealing connection surface 11 between the pressure plate 1 and the sealing plate 3, thereby covering the working window to isolate the main vacuum system within the accelerator unit from the atmospheric environment. During membrane window operation, the vacuum level on the unit side is better than 2.0 × 10⁻⁶. -6 Pa.

[0042] In some embodiments, such as Figure 2 and Figure 4 As shown, the sealing and protection structure includes a transition surface 61, which is connected to the edge of the working window. By setting the transition surface 61 at the edge of the working window, the membrane window uses a smooth curved surface instead of a right angle structure at the edge of the working window. This effectively prevents the isolation membrane 2 from being torn when it is dented due to pressure difference, greatly reducing the possibility of shear damage to the part of the isolation membrane 2 located at the edge of the working window. This significantly improves the operational strength, structural reliability, and safety of the beam terminal membrane window.

[0043] In some specific embodiments, the transition surface is preferably an arc transition surface, as shown in the reference. Figure 2 and Figure 4 As shown, the arc transition surface can better reduce shear stress at the edge of the isolation membrane 2, and is more conducive to the processing, assembly and maintenance of the sealing plate 3.

[0044] In some embodiments, such as Figures 2 to 4As shown, the sealing protection structure also includes at least two levels of protective recesses. Each level of protective recess is continuously connected to the edge of the working window, thus allowing the sealing protection structure to form protection for the isolation membrane 2 outside the edge of the working window using these recesses. Furthermore, the protective recesses form a multi-layered stepped structure. This multi-layered stepped structure ensures that the size of the isolation membrane 2 through which the beam passes decreases progressively from the outside in, keeping the effective scanning area of ​​the working window within the required size range. Moreover, during membrane window operation, since the accelerator's device side is a vacuum environment, the isolation membrane 2 will recede towards the device side (the side of the membrane window with the sealing plate 3) under atmospheric pressure. Because the multi-layered protective recesses form the aforementioned multi-layered stepped structure, the sealing protection structure can reserve space for the receding of the isolation membrane 2 step by step from the sealing connection surface 11 towards the device side using each level of protective recess. Therefore, during the free receding formation of the isolation membrane 2, the membrane window can reliably prevent the isolation membrane 2 from tearing during operation. That is, this setting, on the one hand, uses a multi-layered stepped structure to reserve a recessed space for the working isolation membrane 2, and makes the best use of the stepped space formed by the protective recesses at each level to form edge protection for the working window of the recessed isolation membrane 2. On the basis of improving the protection effect, it can also further assist in increasing the sealing pressure between the pressure plate 1 and the sealing plate 3, thereby improving the sealing performance and structural reliability of the isolation membrane 2 in the membrane window, and thus achieving a reliable seal for the isolation membrane 2 located in the working window.

[0045] In some specific embodiments, the transition surface 61 is preferably disposed on the protective recess closest to the edge of the working window. The smooth curved surface of the transition surface 61 reduces the shear stress of the isolation membrane 2 in the recess at the edge of the working window, thereby effectively reducing or even completely avoiding the possibility of the edge of the isolation membrane 2 in the recess being sheared and damaged.

[0046] In some specific embodiments, such as Figures 2 to 4 As shown, at least two levels of protective recesses include a first recess 6 and a second recess 7. Both the first recess 6 and the second recess 7 are formed on the side of the sealing plate 3 facing the isolation membrane 2, i.e., the sealing connection surface 11. The edge of the working window, the first recess 6, and the second recess 7 are sequentially connected, and the depth of the first recess 6 is greater than the depth of the second recess 7, as shown in the figure. Figure 2As shown, this forms the aforementioned multi-layered stepped structure. Preferably, both the first recessed platform 6 and the second recessed platform 7 are hollow frame structures, and the edges of the working window, the first recessed platform 6, and the second recessed platform 7 gradually increase in size from the inside out, thereby ensuring that the aforementioned multi-layered stepped structure can better fit the concave curvature of the isolation membrane 2, and form protection for the isolation membrane 2 using the smallest reserved space. Thus, the first recessed platform 6 and the second recessed platform 7 can form a nested stepped structure around the periphery of the working window, sinking from the sealing connection surface 11 to the sealing plate 3. That is, the sealing plate 3 is provided with nested first recessed platforms 6 and second recessed platforms 7, preferably the depth and outer dimensions of the first recessed platform 6 are both greater than those of the second recessed platform 7, and the outer dimensions of both the first recessed platform 6 and the second recessed platform 7 are both greater than the working area of ​​the membrane window. The first recessed platform 6, the second recessed platform 7, and the aforementioned square working window all penetrate the entire sealing plate 3.

[0047] In some specific embodiments, since the isolation membrane 2 will be recessed towards the vacuum environment side due to atmospheric pressure during operation, in order to ensure the free deformation of the isolation membrane 2 and prevent damage from the shear force of the sealing plate 3, the transition surface 61 is preferably provided at least at the position where the first recess 6 connects to the edge of the working window. That is, the edge where the first recess 6 contacts the isolation membrane 2 is provided with the aforementioned transition surface 61; or, the transition surface 61 is provided at the edge where the first recess 6 contacts the isolation membrane 2, and also at the connection position of the first recess 6 and the second recess 7. During the operation of the membrane window, the isolation membrane 2 is recessed towards the device side. Since the outer dimensions of the first recess 6 and the second recess 7 are both larger than the working area of ​​the isolation membrane 2 at the working window, sufficient space is reserved for the recess of the isolation membrane 2, so the freely recessed isolation membrane 2 can avoid being torn during operation; moreover, the provision of the transition surface 61 can effectively reduce the shear stress at the position where the isolation membrane 2 connects to the first recess 6, effectively reducing or even completely avoiding the possibility of the edge of the recessed isolation membrane 2 being sheared and damaged.

[0048] In some embodiments, to further improve the sealing performance of the membrane window, particularly the sealing performance of the membrane window operating position (isolation membrane 2), the sealing protection structure preferably further includes a first sealing groove 5. The first sealing groove 5 is formed in the sealing plate 3 and located at the sealing connection surface 11, as detailed below. Figure 2 and Figure 4 As shown. The first sealing groove 5 is disposed around the periphery of the working window, particularly around the periphery of each level of protective recess, and is spaced apart from the protective recess. The first sealing groove 5 forms a reliable seal between the isolation membrane 2 and the sealing plate 3 at the sealing connection surface 11. In this embodiment, the dimensions of the first sealing groove 5 are preferably 6mm × 3.6mm. The sealing ring filled in the first sealing groove 5 is a perfluoroether FFKM rubber sealing ring with an outer diameter of 6mm. The inner side of the first sealing groove 5 is at least 183.5mm from the center of the sealing plate 3. Furthermore, the first sealing groove 5 has a chamfer of R30.

[0049] In some embodiments, such as Figure 1 and Figure 2 As shown, to ensure the airtightness of the connection between the membrane window and the device, the preferred sealing protection structure further includes a second sealing groove 8. The second sealing groove 8 is disposed on the surface of the sealing plate 3 facing away from the sealing connection surface 11, and surrounds the periphery of the working window. The second sealing groove 8 is preferably a rectangular sealing groove. In this embodiment, the dimensions of the second sealing groove 8 are 6mm × 3.6mm. The sealing ring filled in the second sealing groove 8 is a perfluoroether FFKM rubber sealing ring with an outer diameter of 6mm.

[0050] In some embodiments, such as Figures 1 to 4 As shown, the membrane window also includes several sealing holes 9. Each sealing hole 9 passes through the pressure plate 1 and the sealing plate 3. All the sealing holes 9 are arranged around the working window. The sealing holes 9 are used to seal the connection between the pressure plate 1 and the sealing plate 3 via sealing bolts 4. Optionally, the membrane window also includes several connecting holes 10. Each connecting hole 10 passes through the pressure plate 1 and the sealing plate 3, and all the connecting holes 10 are arranged around the working window, with sealing holes 9 provided between adjacent connecting holes 10. The connecting holes 10 are used to connect external devices via connecting bolts. In this embodiment, the complete membrane window passes through several sealing bolts 4 through the pressure plate 1 and the sealing plate 3. Figure 2 The corresponding sealing hole 9 shown connects the pressure plate 1, the isolation membrane 2, the sealing ring, and the sealing plate 3. The length of the sealing bolt 4 is less than the thickness of the membrane window; preferably, the sealing bolt 4 is an M12×55 bolt. The membrane window is connected to the device by connecting bolts passing through it. Figure 3 The connecting hole 10 shown connects the membrane window to the device. The connecting bolt can be of the same bolt structure as the sealing bolt 4. Thus, the membrane window can achieve a reliable sealing connection between the pressure plate 1, the isolation membrane 2, and the sealing membrane, and can also achieve a reliable connection between the membrane window as a whole and the accelerator device.

[0051] In some specific embodiments, such as Figure 2 and Figure 5As shown, the pressure plate 1 is preferably made of 304 stainless steel. The thickness of the pressure plate 1 is 30mm, and the surface roughness is Ra3.2. A through-hole square opening, matching the size required for the operation of the isolation membrane 2, is provided in the center of the pressure plate 1, serving as the working window on the atmospheric side. The working window size is at least 320mm × 320mm to ensure the effective scanning area of ​​the beam is at least 320mm × 320mm. Preferably, the pressure plate 1 has regularly arranged, uniformly sized bolt holes with a diameter of Φ13mm along its edges. There are nine holes on each straight edge, with a center-to-center distance of 40mm, and one hole at each of the four diagonal corners, totaling 40 through holes. These holes are for M12 bolts to pass through. Some of these bolt holes are used to connect with the titanium membrane, sealing plate 3, and sealing ring to form a complete titanium membrane window; other through holes are used to connect the complete membrane window structure to the device. That is, as... Figure 2 and Figure 3 The sealing hole 9 and the connecting hole 10 are shown.

[0052] In some specific embodiments, such as Figures 1 to 4 As shown, the preferred sealing plate 3 is also made of 304 stainless steel. The thickness of the sealing plate 3 is 30mm, and the surface roughness is Ra3.2. A square opening with the same size as the opening of the pressure plate 1 is opened in the middle of the sealing plate 3 facing the vacuum environment side, thus forming the part of the working window on the vacuum environment side. Several bolt through holes and several through holes are arranged in the same manner as the pressure plate 1 around the outer edge of the working window of the sealing plate 3. The bolt through holes are M12 through thread holes, which are used to connect with the sealing bolts 4 passing through the pressure plate 1, thereby achieving a sealed connection of the isolation membrane 2. The length of the sealing bolts 4 is less than or equal to the thickness of the membrane window; otherwise, interference will occur at the device connection surface, affecting the connection with the device. In this embodiment, the sealing bolts 4 used for the membrane window are hexagonal head fully threaded M12×55 bolts with a preload of 25 N·m. VACSEAL high vacuum sealant is applied to the threads to ensure that the thread micro-leakage is ≤1×10 -11 mbar·L / s. The through hole of the sealing plate 3 is the same size as the through hole of the pressure plate 1 and is unthreaded. The two are connected and together form a connecting hole 10 with a length of 60mm and a diameter of 13mm, which is used to connect the membrane window to the device.

[0053] In some specific embodiments, rubber sealing rings are placed in both the first sealing groove 5 and the second sealing groove 8. That is, the sealing plate 3 has rectangular first sealing grooves 5 and second sealing grooves 8 on the pressure film surface (i.e., the sealing connection surface 11 mentioned above) and the connection surface with the device, respectively, for placing rubber sealing rings. The rubber sealing rings are made of perfluoroether FFKM rubber with a hardness of Shore A 85±5, a compression ratio of 18%, and an air exudation rate far lower than that of standard fluororubber.

[0054] In some specific embodiments, the isolation membrane 2 is made of titanium. The titanium membrane is preferably made of TA1 grade industrial pure titanium, supplied in an annealed state, with a thickness of 200 μm. Its mechanical properties at room temperature are: tensile strength Rm ≥ 350 MPa, yield strength Rp0.2 ≥ 250 MPa, elongation ≥ 30%, grain size 6-8, elastic modulus 108 GPa, and Poisson's ratio 0.34. The external dimensions of the isolation membrane 2 are consistent with those of the pressure plate 1 and the sealing plate 3. Sealing holes 9 and connecting holes 10 are formed on the edge of the isolation membrane 2, corresponding to the positions of the pressure plate 1 and the sealing plate 3, and the size of each hole corresponds exactly to that of the pressure plate 1. The outer diameter of both the sealing holes 9 and the connecting holes 10 is 13 mm. The position of the isolation membrane 2 is fixed on the sealing plate 3 by sealing bolts 4 to prevent slippage, while the sealing ring on the sealing plate 3 achieves overall sealing of the membrane window.

[0055] It should be noted that the pressure plate 1 and sealing plate 3 described in this invention are preferably, but not limited to, made of stainless steel, and other metal materials may also be selected based on actual working conditions. The rubber sealing ring, provided it meets the requirements for sealing performance and vacuum level, is not limited to perfluoroelastomer (FFKM) rubber; standard fluororubber materials are also suitable for this structure. The sealing bolts 4 of the membrane window are silver-plated bolts to facilitate the replacement of the isolation membrane 2. For the isolation membrane 2, the titanium membrane thickness used in this embodiment of the invention is 200 μm. This thickness can be adjusted according to specific application scenarios. For example, in devices such as particle accelerators, the commonly used titanium membrane thickness range is 8~50 μm. If a titanium membrane of other thicknesses is selected, the structure of the pressure plate 1 and sealing plate 3 should be designed and verified accordingly to ensure the overall sealing reliability and mechanical stability of the structure.

[0056] In one specific embodiment, the isolation membrane 2 is a titanium membrane made of industrial pure titanium. The pressure plate 1 and the sealing plate 3 are made of 304 stainless steel with a surface roughness of Ra3.2. The pressure plate 1 and the edge of the isolation membrane have 40 Φ13 through holes, 20 of which are used to assemble the membrane window, and the other 20 are used to connect the membrane window to the device. The sealing plate 3 also has 40 through holes, 20 of which are M12 threaded through holes, i.e., sealing holes 9, used to form a complete membrane window with the pressure plate 1, isolation membrane 2, and sealing plate 3. The length of the M12 sealing bolts 4 used to assemble the membrane window is less than or equal to the thickness of the membrane window; otherwise, interference will occur at the connection surface with the device. Therefore, in this embodiment, M12×55 fully threaded bolts are used as sealing bolts 4 to assemble the membrane window. The threads of the sealing bolts 4 are coated with VACSEAL high-vacuum sealant. The other 20 Φ13 holes and the M12 bolts passing through the pressure plate 1 are used to connect the device. The first sealing groove 5 and the second sealing groove 8 on the sealing plate 3 are both rectangular sealing grooves, each with a specification of 3.6×6mm. The sealing ring is a perfluoroether FFKM rubber sealing ring with an outer diameter of Φ6mm.

[0057] To verify the strength and operational status of the membrane window, finite element analysis was performed as follows. The titanium membrane exhibits a maximum stress of 197 MPa under a pressure difference of 1 atm, located at the edge of the working surface, with a safety factor of 1.78 and a maximum deflection of 4.6 mm. A pressure resistance test was conducted on the membrane window using a molecular pump unit for 120 hours of vacuum evacuation. The titanium membrane showed a 5 mm indentation in the middle without any damage, indicating that the structure meets the strength requirements. In the comparative example, the selected sealing protection structure does not have a transition surface 61 in the protective recess, while other conditions are consistent with the membrane window in the embodiment. Finite element analysis showed that the safety factor of the comparative membrane window decreased to 1.6. Therefore, the sealing protection structure with a transition surface plays a crucial role in improving the operational strength of the isolation membrane 2, effectively preventing the isolation membrane 2 from tearing during operation and effectively reducing or even completely eliminating the possibility of shear damage to the edge of the recessed isolation membrane 2.

[0058] During the membrane window assembly process, the pre-formed pressure plate 1, sealing plate 3, sealing bolts 4, and rubber sealing rings are first ultrasonically cleaned, and then placed in a vacuum clean room to air dry. The surface of the titanium membrane is carefully wiped with alcohol to ensure no contaminants remain. The entire assembly operation is carried out under strictly controlled clean conditions. Operators wear sterile gloves and masks throughout the process, and all tools are thoroughly cleaned with alcohol to avoid introducing contaminants and ensure the vacuum performance of the membrane window.

[0059] In this embodiment of the invention, the processed large-size square membrane window test specimen was subjected to vacuum leak detection and pressure resistance testing, with a leak detection rate of 1.5 × 10⁻⁶. -10 mbar·l / s. This indicates that the membrane window has good sealing performance and meets the usage requirements. During the pressure resistance test, the membrane window was connected to the test fixture and evacuated for 120 hours using a molecular pump unit. The membrane window showed no abnormal damage, but the entire titanium membrane was concave in the middle by 5mm.

[0060] During actual operation of the membrane window, the atmospheric pressure on the membrane window side is 1 standard atmosphere, and the vacuum level on the vacuum environment side is better than 2.0 × 10⁻⁶. -6 Pa.

[0061] Therefore, the membrane window described in the embodiments of the present invention has at least the following advantages.

[0062] (1) Compared with the circular membrane window structure, the square large-size membrane window of the present invention has a significantly reduced weight.

[0063] (2) The membrane window of the present invention has good sealing performance and a leak detection rate of 1.5×10⁻⁶. -10 mbar·l / s.

[0064] (3) The membrane window of the present invention has strong pressure resistance. When the pressure resistance test was carried out by evacuating the membrane window for 120 hours with a molecular pump unit, no damage occurred.

[0065] (4) The membrane window structure of the present invention is simple and easy to process and manufacture.

[0066] (5) The membrane window of the present invention can be reused, the titanium membrane is easy to replace, and the maintenance cost is low.

[0067] (6) The proton and heavy ion beams through the membrane window of the present invention have relatively low energy loss after passing through the titanium membrane.

[0068] Based on the above-described membrane window structure, this embodiment of the invention also provides a beam terminal, including the aforementioned beam terminal membrane window. By setting the above-described beam terminal membrane window, the beam terminal possesses all the advantages of the aforementioned beam terminal membrane window, which will not be elaborated further here.

[0069] Based on the above-described membrane window structure, embodiments of the present invention also provide a particle accelerator, including the aforementioned beam termination membrane window; or including the aforementioned beam termination. By setting the aforementioned beam termination membrane window, the particle accelerator possesses all the advantages of the aforementioned beam termination membrane window, which will not be elaborated further here.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A beam terminal membrane window, characterized in that, include: The pressure plate is located on the atmospheric environment side; A sealing plate is disposed on the vacuum environment side, and the sealing plate is sealed to the pressure plate at the sealing connection surface; The working window extends through the pressure plate and the sealing plate; An isolation membrane is provided on the sealing connection surface, and the isolation membrane seals and covers the working window; A sealing and protective structure is disposed on the sealing plate and at the edge of the working window; wherein, the sealing and protective structure includes a transition surface and at least two levels of protective recesses, each level of the protective recesses being continuously connected to the edge of the working window, and the transition surface being disposed at least on the protective recess closest to the edge of the working window; The sealing and protective structure is used to seal the isolation membrane between the sealing plate and the pressure plate, so as to use the protective recesses of each level to reserve space for the recessed isolation membrane from the sealing connection surface to the vacuum environment side, forming a stepped space; the stepped space and the transition surface work together on the working window.

2. The beam terminal membrane window according to claim 1, characterized in that, The at least two-level protective recess includes a first recess and a second recess, both of which are formed on the side of the sealing plate facing the isolation membrane. The edge of the working window, the first recess, and the second recess are sequentially connected, and the depth of the first recess is greater than the depth of the second recess. The transition surface is at least located at the position where the first recess connects to the edge of the working window.

3. The beam terminal membrane window according to claim 1, characterized in that, The sealing protection structure further includes a first sealing groove, which is formed on the sealing plate and located on the sealing connection surface; the first sealing groove surrounds the periphery of each level of the protective recess, and the first sealing groove is spaced apart from the protective recess.

4. The beam terminal membrane window according to claim 1, characterized in that, The sealing protection structure further includes a second sealing groove, which is disposed on the surface of the sealing plate opposite to the sealing connection surface, and the second sealing groove surrounds the periphery of the working window.

5. The beam termination membrane window according to any one of claims 1-4, characterized in that, It also includes a number of sealing holes, each of which passes through the pressure plate and the sealing plate; all of the sealing holes are arranged around the working window; the sealing holes are used to seal the connection between the pressure plate and the sealing plate by sealing bolts.

6. The beam terminal membrane window according to claim 5, characterized in that, It also includes several connecting holes, each of which passes through the pressure plate and the sealing plate. All the connecting holes are arranged around the working window, and the sealing holes are provided between adjacent connecting holes. The connecting holes are used to connect external devices by connecting bolts.

7. The beam termination membrane window according to any one of claims 1-4, characterized in that, It also includes at least one of the following: The working window is polygonal; The transition surface is a circular arc transition surface; The separator is a titanium membrane.

8. A beam terminal, characterized in that, Includes the beam terminal membrane window as described in any one of claims 1-7.

9. A particle accelerator, characterized in that, Includes the beam terminal membrane window as described in any one of claims 1-7; or includes the beam terminal as described in claim 8.

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