Getter thin-walled component and method of manufacturing, vacuum chamber assembly and method of vacuum regulation

Abstract

The application discloses an air absorption thin-wall piece, a preparation method, a vacuum chamber assembly and a vacuum control method. The air absorption thin-wall piece is used for being detachably installed in a vacuum chamber of a cyclotron. The air absorption thin-wall piece can be activated and adsorb gas in the vacuum chamber body. The air absorption thin-wall piece is used for being surrounded at a position close to an inner side wall of the vacuum chamber body. The air absorption thin-wall piece is provided with a plurality of openings. The hole inner wall surface area of each opening is greater than at least twice of the corresponding opening cross section area. The application improves the technical problem that, in the prior art, due to the small volume of a compact cyclotron, the available space is small, and it is difficult to maintain a long-time high vacuum state in the vacuum chamber by installing a plurality of low-temperature cold plates or additionally increasing a plurality of vacuum pumps. The air absorption thin-wall piece is installed in the vacuum chamber to assist the existing vacuum pump to jointly maintain a long-time high vacuum state in the vacuum chamber, thereby reducing the requirement on the pumping speed of the vacuum pump itself, and enabling the pumping speed of the commonly used vacuum pump to meet the requirement.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of cyclotron, in particular to an air absorption thin-walled part and a preparation method, a vacuum chamber assembly and a vacuum control method. BACKGROUND

[0002] In a cyclotron, an electric field is used to accelerate particles, and a magnetic field is used to deflect the accelerated particles along a circular orbit. The magnetic field is generated by two magnetic poles, and the direction of the magnetic field is usually perpendicular to the cross section of the vacuum chamber. Charged particles are accelerated by the electric field and make circular motion under the action of the magnetic field. The motion plane of the particles is perpendicular to the direction of the magnetic field. When the particles reach the required energy, they are output from the side wall of the vacuum chamber through a deflection device. The output beam direction is usually horizontal and perpendicular to the direction of the magnetic field. The particles accelerated by the cyclotron can be applied to cancer treatment, isotope production, medical diagnosis and other fields.

[0003] In order to control the beam loss during particle acceleration, the vacuum degree during particle acceleration needs to be maintained in a high range (about 10 -4 ~ 10 -6 Pa), which is usually carried out in a vacuum chamber. However, the gas load in the vacuum chamber is large, which means that a very high pumping speed is required to achieve a working vacuum of about 10 -5 Pa. In order to maintain a high vacuum state in the vacuum chamber, for large cyclotrons, the conventional method is to install multiple low-temperature cold plates in the vacuum chamber to increase the pumping speed or additionally install multiple vacuum pumps for vacuum pumping.

[0004] Although these two technical means can maintain a high vacuum state in the vacuum chamber for a long time, they are not suitable for compact cyclotrons because installing multiple low-temperature cold plates or additionally installing multiple vacuum pumps requires a large amount of space inside or outside the vacuum chamber. The compact cyclotron is small in size, and the volume inside the vacuum chamber and the external size are insufficient to install multiple low-temperature cold plates or additionally install multiple vacuum pumps.

[0005] Compact cyclotrons are widely used in nuclear physics, atomic physics, solid state physics, isotope production, PET diagnosis, proton therapy and other fields due to their small size and low cost. Therefore, it is urgent to improve the compact cyclotron under the premise that the space inside or outside the vacuum chamber is insufficient to maintain a high vacuum state in the vacuum chamber for a long time. A method or device is obtained that can maintain a high vacuum state in the vacuum chamber for a long time without occupying too much space inside or outside the vacuum chamber. SUMMARY

[0006] The application aims to provide an adsorption thin-wall piece, a preparation method, a vacuum chamber assembly and a vacuum control method, so as to solve the technical problem that it is difficult to maintain a long-time high vacuum state in a vacuum chamber by installing multiple low-temperature cold plates or additionally increasing multiple vacuum pumps due to the small volume of a compact cyclotron.

[0007] To achieve the above-mentioned purpose and solve the corresponding technical problems, the application provides an adsorption thin-wall piece structure which can assist a vacuum pump to maintain a long-time high vacuum state in a vacuum chamber, reduce the parameter requirement of the pumping speed of the vacuum pump, and obtain a high vacuum degree due to the self-baking function, and the adsorption thin-wall piece structure occupies a small space and does not need to additionally increase a vacuum pump or add multiple low-temperature cold plates, and the adsorption thin-wall piece structure in the vacuum chamber can also reduce the radioactivity caused by the activation of the main vacuum chamber wall due to beam loss.

[0008] In addition, the application also provides a vacuum control method of a cyclotron vacuum chamber provided with the adsorption thin-wall piece, which can effectively maintain the vacuum degree of the vacuum chamber for a long time without additionally increasing a vacuum pump, and can also reduce the working frequency and energy consumption of the existing vacuum pump.

[0009] To solve the above-mentioned technical problems, the application adopts the following technical scheme:

[0010] On one hand, the application provides an adsorption thin-wall piece which is detachably installed in a vacuum chamber of a cyclotron, the adsorption thin-wall piece can be activated and adsorb the gas in the vacuum chamber body, the adsorption thin-wall piece is used to surround the position close to the inner side wall of the vacuum chamber body, and a through hole is formed in the adsorption thin-wall piece for beam extraction.

[0011] The scheme improves the technical problem in the prior art that it is difficult to maintain a long-time high vacuum state in a vacuum chamber by installing multiple low-temperature cold plates or additionally increasing multiple vacuum pumps due to the small volume of a compact cyclotron, the adsorption thin-wall piece is installed in the vacuum chamber to assist the existing vacuum pump to jointly maintain a long-time high vacuum state in the vacuum chamber, thereby reducing the requirement of the pumping speed of the vacuum pump itself, and the pumping speed of the commonly used vacuum pump can meet the requirement. Meanwhile, the existence of the through hole does not affect the movement of the gas itself.

[0012] The getter thin-wall member is installed around the position close to the inner wall of the vacuum chamber body, which can protect the inner wall of the vacuum chamber. When the vacuum chamber is working, the beam current will be lost, and the lost beam current will hit the inner wall of the vacuum chamber, thereby causing the inner wall of the vacuum chamber to be activated to produce radioactivity. At this time, the getter thin-wall member can help intercept part of the lost beam current, thereby reducing the possibility of the inner wall of the vacuum chamber being activated to produce radioactivity due to beam current loss.

[0013] As a preferred, the getter thin-wall member comprises a tubular frame, and a plurality of openings are provided on the getter thin-wall member, and the inner wall surface area of each opening is greater than at least twice the cross-sectional area of the corresponding opening; each opening is uniformly provided on the tubular frame, and the inner and outer surfaces of the tubular frame and the inner wall surface of each opening are covered with a getter film, and the getter film can adsorb the gas in the vacuum chamber body. The plurality of openings increase the surface area of the getter thin-wall member, thereby improving the gettering efficiency of the getter thin-wall member; the getter film structure can maximize the getter area on the surface of the getter thin-wall member, and the surface of the getter thin-wall member first contacts the gas molecules. The surface film structure can enable the getter thin-wall member to quickly adsorb the gas molecules during work, and the getter film covering the inner and outer surfaces and the inner wall surface of the openings can increase the adsorption amount of the gas and enhance the gettering effect, so as to more easily maintain the high vacuum state in the vacuum chamber.

[0014] As a preferred, the getter film is a titanium-based film. The titanium-based film can provide uniform surface coverage, which helps to improve the gettering efficiency, and the titanium-based film has a low infrared emissivity, which is beneficial to reducing heat radiation loss and facilitating uniform temperature distribution in the vacuum chamber, thereby improving the operation stability of the cyclotron.

[0015] As a preferred, the getter thin-wall member is provided with an electric resistance heater around the outer periphery, and the electric resistance heater is electrically connected to an external power source. The electric resistance heater can be powered to heat and heat the getter thin-wall member to an adsorption activation temperature, and the adsorption activation temperature is used to activate the getter thin-wall member for adsorption. The electric resistance heater can be powered to heat, and the temperature is transmitted to the getter thin-wall member to heat the getter thin-wall member synchronously, and the heating temperature gradually rises to the adsorption activation temperature, thereby enabling the getter thin-wall member to start working. If it is necessary to stop the adsorption work of the getter thin-wall member, the electric resistance heater can be powered off. In addition, the temperature of the electric resistance heater during the temperature rising stage before the temperature rising to the temperature for activating the getter thin-wall member also has a baking effect on the vacuum chamber, which can reduce the probability of the gas in the vacuum chamber adhering to the inner wall of the vacuum chamber, so that the gas in the vacuum chamber can be removed as much as possible or adsorbed by the getter thin-wall member.

[0016] As preferred, the getter thin-walled member is in a tubular structure and has a circular cross section, and the electric resistance heater is a ring-shaped electric resistance heater, which is arranged at a middle part of a radial outer periphery of the getter thin-walled member. Correspondingly, the present solution is applicable to a vacuum chamber with a sidewall in a circular tubular structure, can better adapt to the shape of the sidewall of the vacuum chamber, can help to intercept as much as possible the lost beam, and reduce the possibility of radioactivity due to the activation of the inner wall of the vacuum chamber by the lost beam. Fixing the ring-shaped electric resistance heater at the middle part of the radial outer periphery of the tubular structure can make the heating of the electric resistance heater on the getter thin-walled member more uniform, and can make the getter thin film activated as much as possible at the same time and enter the gettering state.

[0017] In another aspect, the present solution also provides a preparation method of a getter thin-walled member, for preparing the getter thin-walled member as described above, comprising the following steps:

[0018] S1, preparing two plate frames and uniformly opening a plurality of openings on the plate frames;

[0019] S2, forging the two plate frames prepared in step S1 into a half-cylindrical structure respectively, and welding the two ends of the two half-cylindrical structures to form a tubular frame with a circular cross section;

[0020] S3, annealing the tubular frame obtained in step S2 and cleaning and drying;

[0021] S4, placing the tubular frame after cleaning and drying into a vacuum environment, when the vacuum environment reaches a preset vacuum degree, introducing an inert gas into the vacuum environment, and using a getter material as a raw material to uniformly plate a getter thin film on the surface of the tubular frame, continuously heating at a constant temperature for a preset time after the plating is completed, to obtain the getter thin-walled member.

[0022] In actual application, the thickness of the getter thin-walled member is about 10 mm, so the plate frame is first prepared, then the half-cylindrical structure is forged, and finally the two half-cylindrical structures are welded, to obtain a getter thin-walled member with a more accurate preset shape. The present preparation method can uniformly plate the getter thin film on the outer surface and the inner surface of the tubular frame, including the inner wall surface of each opening, to ensure that the prepared getter thin-walled member can realize good gettering function on the basis of complete structure.

[0023] In still another aspect, the application further provides a vacuum chamber assembly for a cyclotron, comprising a vacuum chamber body, wherein the getter thin-wall member as described above is mounted in the vacuum chamber body; the vacuum chamber body is enclosed by a first magnet, a second magnet and a liner structure, wherein the first magnet and the second magnet are respectively sealingly mounted at two ends of the liner structure; the getter thin-wall member is mounted at a position close to the inner wall of the liner; the liner has a beam outlet, and the getter thin-wall member has a through hole at a corresponding position, wherein the beam can pass through the through hole and be guided out of the beam outlet. The scheme installs a small-volume getter thin-wall member in the vacuum chamber, utilizes the gap space between the magnets and the inner wall of the vacuum chamber, improves the space utilization, does not occupy the space of other functional components in the vacuum chamber, does not occupy the space outside the vacuum chamber, does not need to add an additional vacuum pump, and can achieve the technical effect of maintaining a long-time high-vacuum state in the vacuum chamber.

[0024] Preferably, the first magnet and the second magnet respectively have a plurality of first protrusions and a plurality of second protrusions on the opposite side, and each first protrusion and each second protrusion have an acceleration space between the opposite sides; the outer circumferential side of each first protrusion and the inner wall of the liner have a first ring gap, and the outer circumferential side of each second protrusion and the inner wall of the liner have a second ring gap; a first annular slot is fixed on the first magnet in the first ring gap, and a second annular slot is fixed on the second magnet in the second ring gap, wherein the slot directions of the first annular slot and the second annular slot are opposite, and the first annular slot and the second annular slot are respectively used for inserting the two ends of the getter thin-wall member, so that the acceleration space is located in the surrounding range of the getter thin-wall member. The getter thin-wall member is arranged between the first ring gap and the second ring gap, so that the getter thin-wall member can be as close as possible to the inner wall of the liner, and the acceleration space is located in the surrounding range of the getter thin-wall member, which can ensure that as much lost beam as possible can be intercepted by the getter thin-wall member, and can reduce the possibility of radioactivity due to the activation of the inner wall of the vacuum chamber caused by beam loss. In addition, the insertion form makes the installation, disassembly and replacement of the getter thin-wall member very convenient. If the getter performance of the getter thin-wall member is found to be reduced or lost, the same part can be directly replaced for normal work.

[0025] Preferably, the first magnet is provided with a molecular pump and a first cryogenic pump, and the pump outlets of the molecular pump and the first cryogenic pump are respectively communicated with the interior of the vacuum chamber body; the pump outlet of the molecular pump is provided with a fourth valve, and the pump outlet of the first cryogenic pump is provided with a first valve; the second magnet is provided with a second cryogenic pump and a third cryogenic pump, and the pump outlets of the second cryogenic pump and the third cryogenic pump are respectively communicated with the interior of the vacuum chamber body; the pump outlet of the second cryogenic pump is provided with a second valve, and the pump outlet of the third cryogenic pump is provided with a third valve. In use, the molecular pump is first used to rapidly pump to vacuum, and when the vacuum degree reaches the vacuum degree at which the getter works, the getter thin-wall part is activated to maintain the high vacuum degree of the main vacuum chamber; at this time, the getter thin-wall part and the cryogenic pumps are used in cooperation to maintain the vacuum state; when the getter performance of the getter thin-wall part reaches the limit, only the vacuum degree needs to be reduced to the vacuum atmospheric pressure, the vacuum chamber is opened, and the new getter thin-wall part is replaced.

[0026] In another aspect, the application further provides a vacuum control method, which utilizes the vacuum chamber assembly as described above, and comprises the following steps:

[0027] A1, the fourth valve, the first valve, the second valve and the third valve are opened, and the vacuum chamber is coarsely pumped to vacuum;

[0028] A2, when the vacuum degree reaches the first preset vacuum degree, the molecular pump is started to work to further pump to vacuum;

[0029] A3, when the vacuum degree reaches the second preset vacuum degree, the fourth valve, the first valve, the second valve and the third valve are closed, and the first cryogenic pump, the second cryogenic pump and the third cryogenic pump are started;

[0030] A4, when the cryogenic pumps work at full pumping speed, the first valve, the second valve and the third valve are opened, and further pumping to vacuum is started;

[0031] A5, when the vacuum degree reaches the third preset vacuum degree, the ring-shaped resistance heater is started to heat the getter thin-wall part;

[0032] A6, when the getter thin-wall part is heated to the getter activation temperature, the getter thin-wall part is activated to start gettering, at this time, any one of the cryogenic pumps is selected to work, and the other two cryogenic pumps are regenerated or closed, so as to maintain the third preset vacuum degree of the vacuum chamber.

[0033] Through the above process, the high vacuum degree of the vacuum chamber can be maintained for a long time, and when the preset vacuum degree is reached, only one cryogenic pump needs to be started due to the existence of the getter thin-wall part, and the other cryogenic pumps do not need to be started, so that the number requirement and pumping speed requirement of the cryogenic pumps can be significantly reduced.

[0034] The present application has the following beneficial effects: the present application provides an air suction thin-walled component structure, which is used to solve the technical problem in the prior art that the compact cyclotron has a small body volume, and thus it is difficult to install multiple low-temperature cold plates or additionally increase multiple vacuum pumps to maintain a long-time high-vacuum state in the vacuum chamber; the present application increases the installation of the air suction thin-walled component in the vacuum chamber to assist the existing vacuum pump to jointly maintain a long-time high-vacuum state in the vacuum chamber, thereby reducing the requirement for the pumping speed of the vacuum pump itself, and enabling the pumping speed of the commonly used vacuum pump to meet the requirement. Meanwhile, the existence of the through hole does not affect the movement of the gas itself, and the multiple openings increase the surface area of the air suction thin-walled component, thereby improving the air suction efficiency of the air suction thin-walled component; in addition, the air suction thin-walled component is installed at a position close to the inner wall of the vacuum chamber body, which can protect the inner wall of the vacuum chamber, help intercept part of the lost beam, and thus reduce the possibility of radioactivity due to the activation of the inner wall of the vacuum chamber caused by beam loss. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to make the purpose, technical scheme and advantages of the application clearer, the present application will be further described in detail below with reference to the drawings, in which:

[0036] Figure 1 The structure diagram of the air suction thin-walled component of the embodiment of the present application.

[0037] Figure 2 The exploded view of the vacuum chamber assembly structure of the embodiment of the present application.

[0038] Figure 3 The cross-sectional structure diagram of the vacuum chamber assembly of the embodiment of the present application.

[0039] Figure 4 The structure diagram of the first annular slot and the second annular slot of the embodiment of the present application.

[0040] Figure 5 The structure diagram of the mold of the embodiment of the present application.

[0041] Explanation of reference numerals: 100, getter thin-walled part; 101, opening; 102, electric resistance heater; 103, through hole; 200, vacuum chamber assembly; 201, vacuum chamber body; 202, first magnet; 203, second magnet; 204, bushing; 205, beam outlet; 206, first protrusion; 207, second protrusion; 208, acceleration space; 209, first ring gap; 210, second ring gap; 211, first ring-shaped slot; 212, second ring-shaped slot; 301, molecular pump; 302, first cryogenic pump; 303, second cryogenic pump; 304, third cryogenic pump; 305, fourth valve; 306, first valve; 307, second valve; 308, third valve; 400, mold; 401, protrusion; 402, groove; 403, track; 404, scraper. DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application.

[0043] It should be noted that similar reference numerals and letters indicate similar items in the following drawings, and therefore, once an item is defined in one drawing, it need not be further defined and explained in subsequent drawings. In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate the orientation or positional relationship shown in the drawings or the orientation or positional relationship in which the product of the present application is usually placed, and are merely for the convenience of describing the present application and simplifying the description, and therefore, cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore, cannot be understood as limiting the present application. In addition, the terms "first", "second", "third", and the like are merely used for differentiation in description and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical", and the like do not mean that the components must be absolutely horizontal or vertical, but can be slightly inclined. For example, "horizontal" merely means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be absolutely horizontal, but can be slightly inclined. In the description of the present application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "arrange", "mount", "connect", "connect" should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0044] This invention can be applied to the field of cyclotrons, and in particular to the maintenance of a high vacuum state in the vacuum chamber of a compact cyclotron for a long time. It solves the technical problem in the prior art that, due to the small size of the compact cyclotron itself and the limited usable space, it is difficult to maintain a high vacuum state in the vacuum chamber for a long time by installing multiple cryogenic cold plates or adding multiple vacuum pumps.

[0045] Specifically, in order to illustrate the technical solution of the present invention in detail, the following embodiments are disclosed.

[0046] Example 1, please refer to Figure 1 This embodiment addresses the technical problem in the prior art where the small size of compact cyclotrons and limited usable space make it difficult to maintain a high vacuum state in the vacuum chamber for extended periods by installing multiple cryogenic cooling plates or adding additional vacuum pumps. This embodiment provides a gas-absorbing thin-walled component 100, detachably installed within the vacuum chamber of the cyclotron. This component can be activated to absorb gas within the vacuum chamber body 201. The gas-absorbing thin-walled component 100 is positioned around the inner wall of the vacuum chamber body and has a perforation for beam extraction. The gas-absorbing thin-walled component 100 provided in this embodiment is small in size, utilizing the slit space between the magnet and the inner wall of the vacuum chamber, improving space utilization without occupying space for other functional components within the vacuum chamber or additional space outside the vacuum chamber. It assists the vacuum pump already installed in the vacuum chamber, eliminating the need for additional vacuum pumps, and can jointly maintain a high vacuum state in the vacuum chamber for extended periods. This reduces the requirements for the pumping speed of the vacuum pump itself; conventional vacuum pumps can meet the requirements. Specifically, jointly maintaining a high vacuum state within the vacuum chamber means jointly maintaining the working vacuum level within the vacuum chamber at 10. -5 ~10 -6 Within the Pa range.

[0047] At the same time, if there is gas in the vacuum chamber, the perforation helps the gas flow in the vacuum chamber, so that it can be extracted or adsorbed as soon as possible. This will prevent gas molecules from being blocked in the narrow gap between the suction thin-walled part 100 and the inner wall of the vacuum chamber, which would make it difficult to extract or adsorb the gas and thus reduce the vacuum level.

[0048] In addition, the suction thin-walled component 100 is installed around the inner wall of the vacuum chamber body 201, which can protect the inner wall of the vacuum chamber. This is because when the vacuum chamber is working, the beam will be lost. The lost beam will hit the inner wall of the vacuum chamber, thereby activating the inner wall of the vacuum chamber and generating radioactivity. At this time, the suction thin-walled component 100 can help intercept part of the lost beam, thereby reducing the possibility of radioactivity generated due to the activation of the inner wall of the vacuum chamber by the beam loss.

[0049] In Embodiment 1, preferably, the suction thin-walled member 100 is positioned around the inner wall of the vacuum chamber body 201; the suction thin-walled member 100 has a plurality of openings 101, and the inner wall surface area of ​​each opening 101 is at least twice the cross-sectional area of ​​the corresponding opening 101. The plurality of openings 101 increases the surface area of ​​the suction thin-walled member 100, thereby improving the suction efficiency of the suction thin-walled member 100.

[0050] In Example 1, as one of the implementations of the getter thin-walled component having getter properties, the getter thin-walled component is made of an alloy with getter properties, or the surface of the getter thin-walled component has a getter film. Specifically, titanium-based alloys can be used as the alloy with getter properties, including but not limited to titanium-aluminum-based alloys (e.g., Ti-Al-V) or titanium-zirconium-based alloys (e.g., Ti-Zr-V). Regarding the getter film on the surface of the getter thin-walled component, the getter film is a titanium-based film or titanium-based coating. Correspondingly, the frame structure of the getter thin-walled component is made of aluminum or zirconium. During fabrication, an aluminum or zirconium material frame is first prepared, and then a titanium-based film or titanium-based coating is prepared on the surface.

[0051] In Embodiment 1, the shape of the opening 101 is one of a square hole, a round hole, a polygonal hole, or an irregular hole.

[0052] In Example 1, the thickness of the air-absorbing thin-walled component 100 is 10 mm.

[0053] Example 2, based on Example 1, please refer to... Figure 1 The structure of the suction thin-walled component 100 is further improved. A resistance heater is provided on the outer periphery of the suction thin-walled component 100. The resistance heater is electrically connected to an external power source. The resistance heater can generate heat when energized, heating the suction thin-walled component 100 to the suction activation temperature. The suction activation temperature is used to activate the suction thin-walled component 100 to perform suction. The resistance heater generates heat when energized, transferring the heat to the suction thin-walled component 100, causing it to heat up synchronously and gradually rise to the suction activation temperature, thus initiating its operation. To stop the suction operation of the suction thin-walled component 100, simply disconnect the power to the resistance heater. Furthermore, because the suction thin-walled component 100 itself has a porous structure, it is easily heated by the resistance heater, allowing for relatively rapid activation. In addition, the heating stage of the resistance heater before it reaches the temperature of the suction thin-walled component also has a baking effect on the vacuum chamber, which can reduce the probability of gas in the vacuum chamber adhering to the inner wall of the vacuum chamber, so that the gas in the vacuum chamber can be pumped away or adsorbed by the suction thin-walled component as much as possible.

[0054] In Example 2, specifically, the range of the inhalation activation temperature is 150–600°C, preferably 500–600°C.

[0055] Example 3, based on Example 2, please refer to... Figure 1 The structure of the getter thin-walled component 100 is further improved. The getter thin-walled component 100 is a tubular structure with a circular cross-section. The resistance heater is an annular resistance heater, which surrounds the radial outer periphery of the tubular structure and is located at the center of the radial outer periphery. Correspondingly, this solution is suitable for vacuum chambers with similarly circular tubular sidewalls, allowing for better adaptation to the shape of the vacuum chamber sidewalls. This helps to intercept some of the lost beam current and reduces the possibility of radioactivity generated due to beam loss activating the inner wall of the vacuum chamber. Fixing the annular resistance heater to the center of the radial outer periphery of the tubular structure allows for more uniform heating of the getter thin-walled component 100, maximizing the simultaneous activation of the getter film and initiation of the getter state.

[0056] Example 4, based on Example 1 or 3, please refer to... Figure 1 The getter thin-walled component 100 includes a tubular frame, with each of the openings 101 uniformly formed on the tubular frame. The inner and outer surfaces of the tubular frame, as well as the inner wall surfaces of each opening 101, are covered with a getter film. This getter film can adsorb gas within the vacuum chamber body 201. By employing a getter film structure, the getter area on the surface of the getter thin-walled component 100 can be maximized. The surface of the getter thin-walled component 100 is the first to contact gas molecules. The surface film structure allows the getter thin-walled component 100 to quickly adsorb gas molecules during operation. Simultaneously, the getter film covering the inner and outer surfaces, as well as the inner wall surfaces of the openings 101, increases the amount of gas adsorbed, enhancing the gettering effect and making it easier to maintain a high vacuum state within the vacuum chamber. In Example 4, specifically, the activation temperature of the getter film is in the range of 500–600°C.

[0057] Example 5, based on Examples 1 and 4, provides a method for preparing a thin-walled suction component, which includes the following steps:

[0058] S1. Prepare two flat plate frames and evenly open multiple openings on the flat plate frames;

[0059] S2. Forge the two flat plate frames obtained in step S1 into semi-cylindrical structures, and weld the two ends of the two semi-cylindrical structures to form a tubular frame with a circular cross-section.

[0060] S3. Anneal the tubular frame obtained in step S2, and then clean and dry it.

[0061] S4. Place the cleaned and dried tubular frame into a vacuum environment. When the vacuum environment reaches a preset vacuum level, introduce an inert gas into the vacuum environment. Use a getter material as raw material to uniformly coat a getter film on the surface of the tubular frame. After the coating is completed, continue to heat at a constant temperature for a preset time to obtain the getter thin-walled part.

[0062] Example 6, based on Examples 4 and 5, uses a titanium-based getter film. Due to the molecular properties of titanium, the titanium-based film has a larger getter capacity. Furthermore, the titanium-based film covers the frame surface, providing uniform surface coverage, which helps improve getter efficiency. Additionally, the titanium-based film has a low infrared emissivity, which helps reduce heat radiation loss, promotes uniform temperature distribution within the vacuum chamber, and improves the operational stability of the cyclotron. In practice, the titanium film can be uniformly deposited on various substrates using methods such as physical vapor deposition. The activation temperature range of the titanium-based film is 500–600°C.

[0063] The technical solution of Example 6 uses the preparation method described in Example 5 to prepare the air-absorbing thin-walled part, which can reduce the preparation difficulty and improve the practical application rate. In practical applications, the thickness of the air-absorbing thin-walled part is about 10mm. Therefore, a flat frame is prepared first, followed by forging of the semi-cylindrical structure, and finally welding of the two semi-cylindrical structures. This yields a relatively precise air-absorbing thin-walled part with a pre-set shape. Furthermore, the air-absorbing thin-walled part has multiple openings, allowing the titanium film to be uniformly deposited on the outer and inner surfaces of the tubular frame, as well as the inner wall surfaces of each opening. This ensures that the prepared air-absorbing thin-walled part achieves good air-absorbing function while maintaining structural integrity. Specifically, the flat frame in step S1 is made of aluminum. For details in step S1, please refer to... Figure 5 The preparation method of using aluminum as the material for the flat plate frame is as follows: First, a mold 400 is prepared, which has multiple protrusions 401. The cross-sectional shape of each protrusion 401 matches the shape of the opening 101, and there are grooves 402 between each protrusion 401. Then, a sufficient amount of molten aluminum is poured into the grooves 402 to ensure that all positions of the grooves 402 are filled with molten aluminum. One end of the mold 400 is provided with a track 403, and a scraper 404 is slidably connected to the track 403. After all the grooves 402 are filled with molten aluminum, the scraper 404 is slid from one end of the mold 400 along the track 403 to the other end to scrape off the excess molten aluminum. The moving end of the scraper 404 corresponds to the position of the groove 402, and an outflow groove is reserved to allow the excess molten aluminum to flow out. After the molten aluminum has completely solidified, the mold is demolded to obtain the flat plate frame.

[0064] Specifically, in step S3, the annealed tubular frame is ultrasonically cleaned and wiped multiple times with ethanol and a lint-free cloth to ensure the cleanliness of the tubular frame. Then, the tubular frame is dried.

[0065] Specifically, in step S4, a multi-arc ion plating method is used for coating, and the preset vacuum degree is greater than 4×10⁻⁶. -3 Pa, the getter material is a titanium target with a purity of 99.99%, the inert material is argon with a purity of 99.995%, and the ionization rate of each arc spot is 60-90%.

[0066] Specifically, in step S4, a multi-arc ion plating machine is used to achieve multi-arc ion plating. The specific operation process is as follows: First, prepare the multi-arc ion plating machine and place the cleaned and dried tubular frame inside the plating machine. Start vacuuming to prepare for plating. Set the corresponding parameters according to the normal plating process, including power, current, voltage, temperature, etc. Turn on the titanium target power supply and set the plating time according to the actual plating thickness required, and wait for the titanium film to be deposited. Heat the coated tubular frame and maintain a constant temperature for 2 hours to ensure that the titanium film is completely bonded to the tubular frame. After the deposition is completed, turn off the plating machine, take out the plating part, and the gas-absorbing thin-walled part can be installed normally for subsequent assembly processes such as the annular resistance heater.

[0067] Example 7: This example provides a vacuum chamber assembly 200. Please refer to [link / reference]. Figure 2 and Figure 3 This is used in a cyclotron accelerator and includes a vacuum chamber body 201. The vacuum chamber body 201 houses the air-absorbing thin-walled component 100 described in Embodiment 1. The vacuum chamber body 201 is enclosed by a first magnet 202, a second magnet 203, and a bushing 204. The first magnet 202 and the second magnet 203 are respectively sealed and installed at both ends of the bushing 204. The air-absorbing thin-walled component 100 is mounted around the inner wall of the bushing 204. The bushing 204 has a beam outlet 205, and a corresponding opening 103 is provided on the air-absorbing thin-walled component 100, allowing the beam to pass through the opening 103 and exit from the beam outlet 205. In this embodiment, a small-volume suction thin-walled component 100 is installed in the vacuum chamber. This utilizes the narrow space between the magnet and the inner wall of the vacuum chamber, which improves space utilization. At the same time, it does not occupy the space of other functional components inside the vacuum chamber, nor does it occupy the space outside the vacuum chamber. It does not require an additional vacuum pump and can achieve the technical effect of maintaining a high vacuum state inside the vacuum chamber for a long time.

[0068] Example 8, based on Example 7, please refer to... Figure 2 , Figure 3 and Figure 4The first magnet 202 and the second magnet 203 each have a plurality of relatively protruding first protrusions 206 and a plurality of relatively protruding second protrusions 207 on their opposite sides. An acceleration space 208 is provided between the opposite sides of each first protrusion 206 and each second protrusion 207. A first annular slot 209 is provided between the outer peripheral side of each first protrusion 206 and the inner wall of the bushing 204, and a second annular slot 210 is provided between the outer peripheral side of each second protrusion 207 and the inner wall of the bushing 204. A first annular slot 211 is fixed on the first magnet 202 in the first annular slot 209, and a second annular slot 212 is fixed on the second magnet 203 in the second annular slot 210. The slots of the first annular slot 211 and the second annular slot 212 are oriented opposite to each other. The first annular slot 211 and the second annular slot 212 are respectively used to insert into the two ends of the air-suction thin-walled component 100, so that the acceleration space 208 is located within the surrounding range of the air-suction thin-walled component 100. By positioning the suction thin-walled component 100 between the first annular slit 209 and the second annular slit 210, the suction thin-walled component 100 can be positioned as close as possible to the inner wall of the bushing 204. Furthermore, the acceleration space 208 is located within the surrounding area of ​​the suction thin-walled component 100, ensuring that as much of the lost beam current as possible is intercepted by the suction thin-walled component 100, thus reducing the possibility of radioactivity generated due to activation of the vacuum chamber wall caused by beam current loss. In addition, the plug-in design makes the installation, disassembly, and replacement of the suction thin-walled component 100 very convenient. If the suction performance of the suction thin-walled component 100 is found to be reduced or absent, it can be directly removed and replaced with the same type of part for normal operation.

[0069] In Example 8, the first and second annular slots are preferably made of insulating and heat-insulating materials, preferably ceramic.

[0070] In Example 8, please refer to Figure 3 and Figure 4 The cross-section of the first annular slot 211 and the second annular slot 212 is V-shaped or concave arc-shaped.

[0071] Example 9, based on Example 8, please refer to... Figure 2A molecular pump 301 and a first cryogenic pump 302 are mounted on the first magnet 202. The pump outlets of the molecular pump 301 and the first cryogenic pump 302 are respectively connected to the interior of the vacuum chamber body 201. A fourth valve 305 is provided at the pump outlet of the molecular pump 301, and a first valve 306 is provided at the pump outlet of the first cryogenic pump 302. A second cryogenic pump 303 and a third cryogenic pump 304 are mounted on the second magnet 203. The pump outlets of the second cryogenic pump 303 and the third cryogenic pump 304 are respectively connected to the interior of the vacuum chamber body 201. A second valve 307 is provided at the pump outlet of the second cryogenic pump 303, and a third valve 308 is provided at the pump outlet of the third cryogenic pump 304. The molecular pump 301 changes the direction of gas molecule movement through a high-speed rotating rotor, causing it to move along a specific path, thereby achieving vacuuming. In this embodiment, the molecular pump can be a turbomolecular pump, diffusion pump, or similar type. The pumping speed of the molecular pump 301 is usually higher than that of the cryogenic pump, making it suitable for rapid vacuuming, reaching speeds of up to 10. -9 Cryogenic pumps can operate without oil, achieving vacuum levels of mbar or even lower, thus avoiding oil vapor contamination. They achieve vacuum by adsorbing gas molecules onto a low-temperature surface (typically cooled by liquid nitrogen or liquid helium), making them suitable for applications requiring extremely high vacuum levels, reaching 10 mbar. -12 At vacuum levels of mbar or even lower, the cryogenic pump's low-temperature surface can adsorb various gas molecules, including water vapor. Cryogenic pumps typically achieve higher vacuum levels than the molecular pump 301. In operation, the molecular pump 301 is used to quickly evacuate the vacuum. Once the vacuum level reaches the operating vacuum level of the getter, the getter thin-walled component 100 is activated to maintain a high vacuum in the main vacuum chamber. At this point, the getter thin-walled component 100 and the various cryogenic pumps work together to maintain the vacuum state. When the getter performance of the getter thin-walled component 100 reaches its limit, simply close the gate valve installed at the front end of the vacuum chamber. Once the vacuum level drops to atmospheric pressure, open the vacuum chamber and replace the getter thin-walled component 100.

[0072] Example 10, based on Example 9, please refer to... Figure 2 and Figure 3 A vacuum control method is provided, utilizing the vacuum chamber assembly 200 as described above, comprising the following steps:

[0073] A1. Open the fourth valve 305, the first valve 306, the second valve 307, and the third valve 308, and perform rough vacuuming of the vacuum chamber; since the suction thin-walled component 100 has multiple openings 101, there will be no area with excessively high local pressure in the vacuum chamber during rough vacuuming, and the presence of the suction thin-walled component 100 will not affect the rough vacuuming process.

[0074] A2. When the vacuum level reaches the first preset vacuum level, start the molecular pump 301 to further evacuate the vacuum.

[0075] A3. When the vacuum level reaches the second preset vacuum level, close the fourth valve 305, the first valve 306, the second valve 307, and the third valve 308, and start the first cryogenic pump 302, the second cryogenic pump 303, and the third cryogenic pump 304.

[0076] A4. When all cryogenic pumps are operating at full speed, open the first valve 306, the second valve 307, and the third valve 308 to begin further vacuuming.

[0077] A5. When the vacuum level reaches the third preset vacuum level, start the ring resistance heater to raise the temperature of the suction thin-walled part by 100°C.

[0078] A6. When the getter thin-walled component is heated to the getter activation temperature, the getter film is activated. At this time, any one cryogenic pump can be selected to work, while the other two cryogenic pumps are regenerated or turned off to maintain the preset vacuum level of the vacuum chamber.

[0079] By controlling the above process, a high vacuum level in the vacuum chamber can be maintained for a relatively long time. Moreover, when the preset vacuum level is reached, due to the presence of the thin-walled suction component, only one cryogenic pump needs to be turned on, and the other cryogenic pumps do not need to be turned on, which can significantly reduce the number of cryogenic pumps required and the pumping speed requirements.

[0080] Specifically, in step A6, when any cryogenic pump needs to be regenerated, the corresponding valve is closed for regeneration, and any other cryogenic pump that does not need to be regenerated is turned on.

[0081] Specifically, as one embodiment of the preset vacuum degree values, the first preset vacuum degree is 10 Pa, and correspondingly, the second preset vacuum degree is 10 Pa. -3 Pa, the third preset vacuum degree is 10. -5 Pa.

[0082] In summary, the gas-absorbing thin-walled component and its preparation method, as well as the vacuum chamber assembly and vacuum control method disclosed in this invention, have the following technical advantages:

[0083] 1. This invention addresses the problem in existing technologies where the small size of compact cyclotrons and limited usable space make it difficult to maintain a high vacuum within the vacuum chamber for extended periods by installing multiple cryogenic cooling plates or adding additional vacuum pumps. The thin-walled suction component provided by this invention is small in size and utilizes the narrow space between the magnet and the inner wall of the vacuum chamber, improving space utilization without occupying space for other functional components within the vacuum chamber or additional space outside the vacuum chamber. It assists the vacuum pump already installed in the vacuum chamber, eliminating the need for additional pumps and enabling sustained high vacuum maintenance within the chamber. This reduces the requirements for the pumping speed of the vacuum pump itself, allowing conventional vacuum pumps to meet the requirements. The thin-walled suction component is detachable for easy replacement.

[0084] 2. If gas is present in the vacuum chamber, multiple openings facilitate gas flow, allowing it to be extracted or adsorbed quickly. This prevents gas molecules from being blocked in the narrow gap between the suction thin-walled component and the inner wall of the vacuum chamber, thus avoiding a decrease in vacuum level. Furthermore, multiple openings increase the surface area of ​​the suction thin-walled component, thereby improving its suction efficiency.

[0085] 3. The air-absorbing thin-walled component is installed around the inner wall of the vacuum chamber body, which can protect the inner wall of the vacuum chamber. This is because when the vacuum chamber is working, the beam will be lost. The lost beam will hit the inner wall of the vacuum chamber, thereby activating the inner wall of the vacuum chamber and producing radioactivity. At this time, the air-absorbing thin-walled component can help intercept part of the lost beam, thereby reducing the possibility of radioactivity caused by the activation of the inner wall of the vacuum chamber due to beam loss.

[0086] 4. The suction thin-walled component disclosed in this invention is further equipped with a resistance heater that can generate heat when energized, and transfer the temperature to the suction thin-walled component to generate heat synchronously, and gradually raise the heating temperature to the suction activation temperature, thereby enabling the suction thin-walled component to start working; in addition, during the heating stage before the temperature of the resistance heater rises to the temperature that activates the suction thin-walled component, it also has a baking effect on the vacuum chamber, which can reduce the probability of gas in the vacuum chamber adhering to the inner wall of the vacuum chamber, so that the gas in the vacuum chamber can be extracted or adsorbed by the suction thin-walled component as much as possible.

[0087] 5. The present invention also provides a getter thin-walled part with a getter film coated on its surface, which reduces the difficulty of preparation and improves the efficiency of gas molecules contacting the getter material, thereby improving the getter efficiency.

[0088] 6. The present invention also provides a vacuum chamber assembly with a suction thin-walled component, which utilizes the slit space between the magnet and the inner wall of the vacuum chamber, improving space utilization while not occupying the space of other functional components inside the vacuum chamber, nor occupying additional space outside the vacuum chamber. It does not require an additional vacuum pump and can achieve the technical effect of maintaining a high vacuum state inside the vacuum chamber for a long time.

[0089] 7. Based on the provided vacuum chamber assembly, the present invention also provides a vacuum control method. Through control, a high vacuum level in the vacuum chamber can be maintained for a longer period of time without the need for additional vacuum pumps. Moreover, when the preset vacuum level is reached, due to the presence of the suction thin-walled component, only one cryogenic pump can be turned on, and the other cryogenic pumps do not need to be turned on. This can significantly reduce the number of cryogenic pumps required and the pumping speed requirement, and can significantly reduce the operating frequency and energy consumption of existing vacuum pumps.

[0090] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Under the teachings of the present invention, modifications can be made to these features and embodiments to adapt to specific situations and materials without departing from the spirit and scope of the invention. The embodiments described in this invention are only a part of the embodiments of the invention, not all of them. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. Therefore, the invention is not limited to the specific embodiments disclosed herein, and all other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A thin-walled suction component for detachable installation within the vacuum chamber of a cyclotron, characterized in that, The gas-absorbing thin-walled component can be activated and adsorb gas inside the vacuum chamber body; the gas-absorbing thin-walled component is used to surround a position near the inner wall of the vacuum chamber body; the gas-absorbing thin-walled component has a through-hole for beam extraction; The gas-absorbing thin-walled component includes a tubular frame with multiple openings. The inner wall surface area of ​​each opening is at least twice the cross-sectional area of ​​the corresponding opening. The openings are uniformly arranged on the tubular frame. The inner and outer surfaces of the tubular frame and the inner wall surface of each opening are covered with a getter film. The getter film can adsorb the gas inside the vacuum chamber body.

2. The air-absorbing thin-walled component according to claim 1, characterized in that, The getter film is a titanium-based film.

3. The air-absorbing thin-walled component according to claim 1, characterized in that, A resistance heater is provided on the outer periphery of the air-absorbing thin-walled component. The resistance heater is electrically connected to an external power source. The resistance heater can generate heat and heat the air-absorbing thin-walled component to the air-absorbing activation temperature. The air-absorbing activation temperature is used to activate the air-absorbing thin-walled component to absorb air.

4. The air-absorbing thin-walled component according to claim 3, characterized in that, The air-absorbing thin-walled component has a tubular structure with a circular cross-section, and the resistance heater is an annular resistance heater that surrounds the center of the radial outer periphery of the air-absorbing thin-walled component.

5. A method for preparing a thin-walled suction component, used to prepare the thin-walled suction component as described in claim 1, characterized in that, Includes the following steps: S1. Prepare two flat plate frames and evenly open multiple openings on the flat plate frames; S2. Forge the two flat plate frames obtained in step S1 into semi-cylindrical structures, and weld the two ends of the two semi-cylindrical structures to form a tubular frame with a circular cross-section. S3. Anneal the tubular frame obtained in step S2, and then clean and dry it. S4. Place the cleaned and dried tubular frame into a vacuum environment. When the vacuum environment reaches a preset vacuum level, introduce an inert gas into the vacuum environment. Use a getter material as raw material to uniformly coat a getter film on the surface of the tubular frame. After the coating is completed, continue to heat at a constant temperature for a preset time to obtain the getter thin-walled part.

6. A vacuum chamber assembly for use in a cyclotron accelerator, characterized in that, Includes a vacuum chamber body, wherein the vacuum chamber body is equipped with the air-suction thin-walled component as described in claim 1; The vacuum chamber body is formed by a first magnet, a second magnet, and a bushing structure. The first magnet and the second magnet are respectively sealed and installed at both ends of the bushing structure. The suction thin-walled component is installed around the bushing near the inner wall of the bushing. The bushing has a beam outlet, and the corresponding position on the suction thin-walled component has a through-hole, through which the beam can pass and be led out from the beam outlet.

7. The vacuum chamber assembly according to claim 6, characterized in that, The first magnet and the second magnet each have a plurality of relatively protruding first protrusions and a plurality of relatively protruding second protrusions on their opposite sides, and there is an acceleration space between the opposite sides of each first protrusion and each second protrusion; Each of the first protrusions has a first circumferential seam between its outer peripheral side and the inner wall of the bushing, and each of the second protrusions has a second circumferential seam between its outer peripheral side and the inner wall of the bushing; A first annular slot is fixed on the first magnet inside the first annular gap, and a second annular slot is fixed on the second magnet inside the second annular gap. The openings of the first annular slot and the second annular slot are opposite to each other. The first annular slot and the second annular slot are respectively used to insert into the two ends of the air intake thin-walled component, so that the acceleration space is located within the surrounding range of the air intake thin-walled component.

8. The vacuum chamber assembly according to claim 7, characterized in that, A molecular pump and a first cryogenic pump are mounted on the first magnet. Correspondingly, the pump outlets of the molecular pump and the first cryogenic pump are respectively connected to the interior of the vacuum chamber body. A fourth valve is provided at the pump outlet of the molecular pump, and a first valve is provided at the pump outlet of the first cryogenic pump. A second cryogenic pump and a third cryogenic pump are mounted on the second magnet. Correspondingly, the pump outlets of the second cryogenic pump and the third cryogenic pump are respectively connected to the interior of the vacuum chamber body. A second valve is provided at the pump outlet of the second cryogenic pump, and a third valve is provided at the pump outlet of the third cryogenic pump.

9. A vacuum control method, utilizing the vacuum chamber assembly as described in claim 8, characterized in that, Includes the following steps: A1. Open the fourth valve, the first valve, the second valve, and the third valve, and perform a rough vacuum in the vacuum chamber; A2. When the vacuum level reaches 10 Pa, start the molecular pump to further evacuate the vacuum. A3. When the vacuum level reaches 10 -3 When Pa is reached, close the fourth valve, the first valve, the second valve, and the third valve, and start the first cryogenic pump, the second cryogenic pump, and the third cryogenic pump. A4. When all cryogenic pumps are operating at full speed, open the first valve, the second valve, and the third valve to begin further vacuuming. A5. When the vacuum level reaches the preset vacuum level, start the annular resistance heater to heat up the suction thin-walled part. A6. When the getter thin-walled component is heated to the getter activation temperature, the getter film is activated. At this time, one cryogenic pump can be selected to work, while the other two cryogenic pumps are regenerated or turned off to maintain the preset vacuum level of the vacuum chamber.

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