A method of cleaning an accelerator vacuum chamber

Abstract

The application relates to the technical field of accelerators and discloses a cleaning method for an accelerator vacuum cavity. The cleaning method comprises the following steps: high-pressure water flushing is performed on the inner wall of the vacuum cavity, and the vacuum cavity is dried; the vacuum cavity is subjected to deep cleaning; the vacuum cavity subjected to the deep cleaning is subjected to ultrasonic cleaning; the vacuum cavity subjected to the ultrasonic cleaning and dried is placed in a vacuum furnace, the vacuum cavity is heated to a first preset temperature at a first speed and kept for a first preset time, and then the vacuum cavity is cooled to a second preset temperature at a second speed; nitrogen is filled into the vacuum furnace, and the vacuum cavity is taken out of the vacuum furnace after the temperature in the furnace is reduced to a third preset temperature. In the application, the technical problems that powder and metal particle composite pollutants caused by thermal runaway of non-evaporative getter alloy are difficult to completely remove are solved by sequentially adopting the synergistic treatment process of high-pressure water flushing, mechanical polishing or pickling, ultrasonic cleaning and finally vacuum furnace low-temperature degassing combination.

Description

Technical Field

[0001] This invention relates to the field of accelerator technology, and in particular to a method for cleaning an accelerator vacuum chamber. Background Technology

[0002] In accelerators, the vacuum chamber is the core component for beam operation and storage. The cleanliness of its inner surface directly determines the ultimate vacuum and operational outgassing rate of the accelerator vacuum system, and is one of the factors affecting beam lifetime. The ultimate vacuum of an ultra-high vacuum system is usually determined by the configuration of the main pump (such as a sputtering ion pump or a titanium sublimation pump) and the system manufacturing process.

[0003] Under the premise of consistent production processes, the local pressure distribution in different areas of the system mainly depends on the layout of the main pump. To further obtain the required ultra-high vacuum environment in areas with limited pumping speed, non-evaporable getter alloys are often introduced. However, in extremely rare special cases, if the non-evaporable getter alloy is not properly fixed and the system leaks, it may cause material displacement, which can lead to thermal runaway or even combustion due to frictional heat generation. This results in alloy powder sputtering and contamination of the inner wall of the vacuum chamber, severely degrading the vacuum performance of the system. This invention aims to provide an efficient and reliable cleaning method for this specific contaminant formed by the combustion of non-evaporable getter alloys. Summary of the Invention

[0004] This invention provides a cleaning method for the vacuum chamber of an accelerator, which solves the cleaning problem caused by particulate composite contaminants resulting from the thermal runaway of non-evaporable getter alloys, and provides technical support for maintaining and restoring the vacuum performance of the accelerator.

[0005] This invention provides a method for cleaning an accelerator vacuum chamber, comprising:

[0006] The inner wall of the vacuum chamber is rinsed with high-pressure water and then dried.

[0007] Perform a deep cleaning on the vacuum chamber;

[0008] The vacuum cavity, after deep cleaning, is subjected to ultrasonic cleaning. After ultrasonic cleaning, the vacuum cavity is transferred to a vacuum clean room to air dry.

[0009] After ultrasonic cleaning and drying, the vacuum chamber is placed in a vacuum furnace. It is first heated to a first preset temperature at a first speed, maintained at the first preset temperature for a first preset time, and then cooled to a second preset temperature at a second speed. Finally, nitrogen gas is introduced into the vacuum furnace. After the temperature inside the vacuum furnace drops to a third preset temperature, the vacuum chamber is removed from the vacuum furnace.

[0010] According to the cleaning method for the accelerator vacuum cavity provided by the present invention, the first velocity ranges from 3℃ / min to 5℃ / min, the first preset temperature ranges from 500℃ to 600℃, the first preset time ranges from 2.5h to 3.5h, the second velocity ranges from 3℃ / min to 5℃ / min, the second preset temperature ranges from 300℃ to 400℃, and the third preset temperature ranges from no more than 80℃.

[0011] According to the cleaning method for the accelerator vacuum cavity provided by the present invention, the first speed is 5℃ / min, the first preset temperature is 550℃, the first preset time is 3h, the second speed is 5℃ / min, the second preset temperature is 350℃, and the third preset temperature is 80℃.

[0012] According to the cleaning method for an accelerator vacuum cavity provided by the present invention, the step of performing deep cleaning of the vacuum cavity includes:

[0013] The inner wall of the vacuum cavity is mechanically polished, or the inner wall of the vacuum cavity is acid-washed.

[0014] According to the cleaning method for an accelerator vacuum cavity provided by the present invention, the step of acid washing the inner wall of the vacuum cavity includes:

[0015] The vacuum cavity is cleaned by filling it with a cleaning solution; wherein the cleaning solution is prepared from stainless steel passivation paste and the mass concentration of the cleaning solution is 3%~3.5%.

[0016] According to the cleaning method for an accelerator vacuum cavity provided by the present invention, the step of performing deep cleaning of the vacuum cavity further includes:

[0017] Apply stainless steel passivation paste to the flange surface of the vacuum chamber, and after a second preset time, wash off the stainless steel passivation paste.

[0018] The cleaning method for an accelerator vacuum chamber according to the present invention further includes, after the step of removing the vacuum chamber from the vacuum furnace:

[0019] After the vacuum chamber has cooled to room temperature, a leak test is performed on the vacuum chamber in the vacuum clean room.

[0020] The cleaning method for an accelerator vacuum chamber according to the present invention, after leak detection of the vacuum chamber in the vacuum cleanroom, further includes:

[0021] If there are no leaks in the vacuum chamber, a sealing cap is installed at the flange port of the vacuum chamber, and nitrogen is introduced for drying and storage.

[0022] If a leak is found in the vacuum chamber, the leak is repaired by welding and then re-inspected to confirm that the leak has been eliminated. Next, the vacuum chamber with the leak eliminated is ultrasonically cleaned.

[0023] According to the cleaning method for the accelerator vacuum chamber provided by the present invention, the inner diameter of the vacuum chamber is 40mm~500mm and the wall thickness of the vacuum chamber is 0.3mm~5mm.

[0024] The cleaning method for accelerator vacuum chambers provided by this invention solves the technical challenge of thoroughly removing composite contaminants of powder and metal particles caused by thermal runaway of non-evaporable getter alloys by employing a synergistic treatment process combining high-pressure water rinsing, mechanical polishing or acid washing, ultrasonic cleaning, and final low-temperature degassing in a vacuum furnace. This method not only effectively removes various contaminants from macroscopic to microscopic levels but also reduces the outgassing rate of the vacuum chamber by decreasing material surface roughness, passivating surfaces, and deeply removing adsorbed gases, thus providing a reliable technical guarantee for restoring and maintaining the ultra-high vacuum performance of the accelerator system. Attached Figure Description

[0025] 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.

[0026] Figure 1 This is a schematic flowchart of the vacuum cavity cleaning method provided by the present invention. Detailed Implementation

[0027] 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.

[0028] In the description of this specification, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are used only for the convenience of describing this specification. They do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this specification. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] In the description of this specification, it should be noted that, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this invention based on the specific circumstances.

[0030] In this specification, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0031] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this specification. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0032] In the embodiments of this specification, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone.

[0033] Before introducing the cleaning method for the accelerator vacuum cavity of the present invention, it should be noted that the cleaning method for the accelerator vacuum cavity provided in the embodiments of the present invention is not only applicable to cleaning the vacuum cavity in the accelerator, but also applicable to cleaning thin-walled cavities such as hydraulic bellows, wherein the wall thickness of the thin-walled cavity is usually 0.3mm to 1mm.

[0034] like Figure 1 As shown, a specific embodiment of the first aspect of the present invention provides a method for cleaning an accelerator vacuum chamber. The method for cleaning the accelerator vacuum chamber includes:

[0035] S100. High-pressure water rinsing of the inner wall of the vacuum chamber and air drying. Specifically, high-pressure water rinsing of the inner wall of the vacuum chamber removes yellow powdery contaminants adhering to it. The vacuum chamber is then placed in a natural environment to air dry. This step, as a preliminary physical cleaning, efficiently and quickly removes large areas of loose contaminants, avoiding early intervention with chemical reagents, reducing the difficulty and cost of subsequent treatments, and laying a good foundation for the following deep cleaning.

[0036] S200, Perform deep cleaning of the vacuum chamber.

[0037] The deep cleaning step of the vacuum chamber includes either mechanical polishing or acid pickling of the inner wall of the vacuum chamber. These mechanical polishing or acid pickling processes remove metal particles adhering to the inner wall of the vacuum chamber. This step provides two optional deep cleaning solutions, enhancing the versatility of the cleaning method. Mechanical polishing not only removes stubborn metal particles but also reduces the surface roughness of the inner wall, thereby reducing the material outgassing rate during subsequent vacuum operation. Acid pickling, on the other hand, dissolves and removes metal particles through a chemical reaction, while simultaneously passivating the stainless steel surface, forming a dense oxide film that improves the chamber's corrosion resistance.

[0038] S300. Perform ultrasonic cleaning on the vacuum chamber after deep cleaning. After ultrasonic cleaning, transfer the vacuum chamber to a vacuum cleanroom to air dry. Specifically, ultrasonic cleaning removes chemical residues from the vacuum chamber after deep cleaning. After ultrasonic cleaning, transfer the vacuum chamber to a vacuum cleanroom to air dry naturally. Ultrasonic cleaning utilizes the "cavitation effect" generated by ultrasound in liquids to thoroughly remove tiny particles and chemical residues remaining on the surface, in micropores, and in geometric dead corners of the chamber after polishing or acid washing, achieving a higher level of cleanliness. Transferring it to a vacuum cleanroom for drying effectively prevents secondary contamination of the clean chamber surface by airborne dust and impurities during the drying process, ensuring the cleaning effect is maintained.

[0039] S400: After ultrasonic cleaning and drying, the vacuum chamber is placed in a vacuum furnace. It is first heated to a first preset temperature at a first rate, maintained at the first preset temperature for a first preset time, and then cooled to a second preset temperature at a second rate. Finally, nitrogen gas is introduced into the vacuum furnace. After the temperature inside the vacuum furnace drops to a third preset temperature, the vacuum chamber is removed from the furnace. The first preset temperature is higher than the second preset temperature, and the second preset temperature is higher than the third preset temperature. This process removes water molecules and other volatile pollutants adsorbed on and near the surface of the vacuum chamber, and also reduces the gas efflux rate of the vacuum chamber. The high temperature provides sufficient desorption energy for gas molecules (especially water molecules) adsorbed on the surface and subsurface of the material. By setting a controllable heating and cooling rate, thermal stress damage to the vacuum chamber (especially thin-walled or complex structures) caused by drastic temperature changes can be effectively avoided. Finally, during the cooling phase, high-purity nitrogen is introduced to break the airflow, which passivates and protects the inner wall surface that has just undergone high-temperature activation treatment, preventing it from rapidly re-adsorbing water vapor and active gases when exposed to the atmosphere. This keeps the cavity in a standby state with a low gas output rate, ensuring that the system's ultimate vacuum can be quickly obtained and maintained in the future.

[0040] In this embodiment, a synergistic treatment process combining high-pressure water rinsing, mechanical polishing or acid washing, ultrasonic cleaning, and final low-temperature degassing in a vacuum furnace solves the technical challenge of completely removing composite contaminants of powder and metal particles caused by thermal runaway of non-evaporable getter alloys. This method not only effectively removes various contaminants from macroscopic to microscopic levels but also reduces the outgassing rate of the vacuum chamber by decreasing material surface roughness, passivating surfaces, and deeply removing adsorbed gases, thus providing a reliable technical guarantee for restoring and maintaining the ultra-high vacuum performance of the accelerator system.

[0041] Optionally, the inner diameter of the vacuum chamber is 40mm to 500mm. In other words, the inner diameter of the vacuum chamber can be 40mm, 500mm, 100mm, 250mm, 350mm, or 450mm. This size range covers a variety of specifications, from compact beam pipes to large experimental chambers, demonstrating the wide applicability of the cleaning method in this embodiment and its ability to meet the cleaning needs of different functional components in accelerator systems.

[0042] The wall thickness of the vacuum chamber ranges from 0.3mm to 5mm. In other words, the wall thickness of the vacuum chamber can be 0.3mm, 5mm, 2mm, 3mm, or 4mm. This range of wall thickness takes into account both the structural sensitivity of thin-walled components such as bellows and the mechanical strength requirements of conventional chambers. This indicates that the cleaning process proposed in this embodiment can ensure the cleaning effect while avoiding physical or thermal stress damage to chambers with different wall thicknesses, thus guaranteeing the integrity and reliability of the components.

[0043] Different cleaning methods can be selected based on the inner diameter of the vacuum cavity. For example, for vacuum cavities with small cross-sections (i.e., smaller inner diameters), acid washing can be performed on the inner wall to achieve deep cleaning. For vacuum cavities with large cross-sections (i.e., larger inner diameters), mechanical polishing can be performed on the inner wall to achieve deep cleaning.

[0044] It should be noted that vacuum cavities with an inner diameter of less than 300 mm are generally defined as small-diameter vacuum cavities, while vacuum cavities with an inner diameter of 300 mm or more are generally defined as large-diameter vacuum cavities.

[0045] Optionally, the step of acid washing the inner wall of the vacuum chamber includes: filling and cleaning the vacuum chamber with a cleaning solution; wherein the cleaning solution is prepared from stainless steel passivation paste, and the mass concentration of the cleaning solution is 3%~3.5%. This concentration range ensures the chemical activity of dissolving metal particulate contaminants while avoiding excessive corrosion and damage to the vacuum chamber substrate due to excessive acidity, achieving a balance between cleaning effectiveness and material safety. Essentially, it involves adding stainless steel passivation paste to deionized water to prepare a cleaning solution with a mass concentration of 3%~3.5%. Using deionized water as a solvent avoids introducing new ionic impurities at the source, thus ensuring the purity of the entire cleaning process. The cleaning solution is then poured into the vacuum chamber, ensuring complete immersion of the inner wall. This pouring method guarantees that the cleaning solution reaches all inner surfaces of the vacuum chamber without any blind spots. During the pickling process, the vacuum chamber is gently agitated every 2-3 hours. This utilizes fluid shear force to detach metal particles adhering to the inner wall, enhancing the physical peeling effect and helping to maintain the homogeneity and reactivity of the solution composition, ensuring consistent treatment of the inner wall. After the pickling time reaches the preset time (e.g., 24 hours), the cleaning solution is drained from the vacuum chamber, and the chamber is then rinsed with high-pressure water. This rinsing removes all chemical residues and detached particles, preventing them from becoming potential sources of contamination and venting in the subsequent vacuum environment. This completes the pickling of the inner wall of the vacuum chamber, removing metal particles and reforming a dense passivation protective film on the stainless steel surface, improving the chamber's corrosion resistance.

[0046] Optionally, the mass concentration of the cleaning solution can be 3%, 3.2%, or 3.5%.

[0047] In some embodiments of the present invention, the first speed ranges from 3°C / min to 5°C / min. In other words, the first speed can be 3°C / min, 5°C / min, or 4°C / min. This controlled heating rate can reduce the risk of thermal stress caused by excessive temperature difference while ensuring uniform heating of the vacuum cavity, protecting the structural integrity of the vacuum cavity (especially thin-walled or complex structural components) and preventing deformation or damage.

[0048] The first preset temperature ranges from 500℃ to 600℃. In other words, the first preset temperature can be 500℃, 600℃, or 550℃. The first preset temperature provides sufficient desorption energy for water molecules and other volatile pollutants such as hydrocarbons adsorbed on and near the material surface, in order to achieve a thorough degassing effect and ensure that an ultra-high vacuum environment can be obtained.

[0049] The first preset time ranges from 2.5h to 3.5h. In other words, the first preset time can be 2.5h, 3.5h, or 3h. As the heat preservation duration, the first preset time ensures that the process of gas diffusion from the material to the surface is fully carried out, making degassing more thorough and thus obtaining a stable and extremely low long-term gas outflow rate.

[0050] The second velocity ranges from 3℃ / min to 5℃ / min. In other words, the second velocity can be 3℃ / min, 5℃ / min, or 4℃ / min. Similar to the heating process, this controllable cooling rate is also to prevent thermal shock and avoid deformation or microcracks in the vacuum chamber due to a sudden drop in temperature during the cooling process.

[0051] The second preset temperature ranges from 300℃ to 400℃. In other words, the second preset temperature can be 300℃, 400℃, or 350℃. High-purity nitrogen is introduced at the second preset temperature. The introduction of high-purity nitrogen reduces the vacuum level of the vacuum furnace, improves heat exchange within the furnace, thereby achieving rapid cooling. Simultaneously, it also creates an inert atmosphere protective layer on the surface of the vacuum chamber, ensuring the cleanliness of the chamber.

[0052] The third preset temperature range is no greater than 80℃. In other words, the third preset temperature can be 80℃, 70℃, or 60℃. The third preset temperature ensures that the vacuum chamber can be safely removed from the furnace for subsequent operations, avoiding both the risk of burns from high temperatures and oxidation of the vacuum chamber, which facilitates the rapid connection of subsequent processes.

[0053] In some embodiments of the present invention, the step of deep cleaning the vacuum cavity further includes:

[0054] Apply stainless steel passivation paste to the flange surface of the vacuum chamber, and after a second preset time, wash off the stainless steel passivation paste.

[0055] In this embodiment, for flange surfaces with precision metal cutting edges or similar structures, a chemical paste is used for treatment. This avoids physical damage such as scratches and deformation that may occur with mechanical polishing, thus protecting the integrity and precision of the vacuum sealing surface. The passivation paste, through its chemical composition, can gently dissolve and peel off stubborn metal particles adhering to the flange surface, thereby removing metal particles from the flange surface without damaging critical structures. Combined with cleaning the inner wall of the vacuum chamber, this forms a comprehensive "inner wall-port" cleaning method, achieving thorough and deep cleaning of the vacuum chamber. This ensures that all surfaces in contact with vacuum, from the inside of the chamber to the connection ports, meet a high cleanliness standard, eliminating potential sources of contamination for the system to achieve excellent vacuum performance.

[0056] For example, to avoid mechanical damage to the blades of a precision metal cutting edge, a stainless steel passivation paste is applied to the flange surface, left to stand for 30 minutes, and then rinsed with a high-pressure water gun until the metal particles are completely removed.

[0057] It should be noted that stainless steel passivation paste is a chemical preparation used to remove oxide scale and weld spots (yellow, blue, and black) generated after welding and high-temperature processing of stainless steel. It is suitable for ferritic, austenitic, and other stainless steels (304, 316, 316L, 321, etc.), and can passivate the surface to form a chromium-based oxide film to improve corrosion resistance and make the surface bright and new. Stainless steel passivation paste is prior art, therefore its composition is not described in detail in the specific embodiments of this invention.

[0058] In some embodiments of the present invention, after removing the vacuum chamber from the vacuum furnace, the process further includes: after the vacuum chamber has cooled to room temperature, performing a leak test on the vacuum chamber in a vacuum cleanroom. This avoids using a vacuum chamber with leaks in the vacuum system. This final quality control step ensures that only structurally intact and completely sealed qualified vacuum chambers can proceed to subsequent assembly stages, eliminating the risk from the outset that even minor leaks could prevent the entire vacuum system from reaching the target vacuum level or achieving long-term stable operation.

[0059] Optionally, after leak testing of the vacuum chamber within the vacuum cleanroom, the following steps may also be taken:

[0060] Assuming there are no leaks in the vacuum chamber, a sealing cap is installed at the flange port of the vacuum chamber, and nitrogen is filled in for drying and storage. This allows for easy access later. The sealing cap protects the delicate flange sealing surface from physical damage such as scratches or impacts, and also provides a reliable physical barrier for internal gas filling and storage. Filling with high-purity nitrogen displaces the humid air inside the chamber, preventing the clean inner walls, which have just undergone high-temperature activation treatment, from re-adsorbing water molecules and other reactive gases, thus maintaining the chamber in an ideal state of low gas outflow rate for a long period.

[0061] In cases where leaks exist in the vacuum chamber, the leaks are repaired by welding and then re-inspected to confirm that the leaks have been eliminated. Following this, the vacuum chamber with the leaks eliminated undergoes ultrasonic cleaning (as described in S300) and subsequent vacuum furnace heat treatment (as described in S400). This ensures the cleanliness of the repaired vacuum chamber. Welding repair allows for the recycling of defective vacuum chambers, avoiding overall scrapping due to localized defects and reducing costs. Re-inspection of the repaired vacuum chamber ensures the effectiveness of the repair and the structural sealing of the vacuum chamber, preventing defective products from entering the next stage. Because the welding process itself introduces new contaminants and creates a heat-affected zone, repeated cleaning and heat treatment steps are necessary. This removes surface contaminants from welding and vents the repaired area, ultimately ensuring that the repaired vacuum chamber not only has no leaks but also fully restores its overall cleanliness and vacuum performance to acceptable standards, making it indistinguishable from an unrepaired component.

[0062] For example, in the case of a leak in the vacuum chamber, the leak is repaired by welding. After welding, the weld is ground and polished as necessary, and the area is re-inspected to confirm that the leak has been eliminated. Following this, the vacuum chamber undergoes ultrasonic cleaning and subsequent heat treatment in a vacuum furnace. The heat treatment process includes placing the ultrasonically cleaned vacuum chamber in a vacuum with a vacuum level of less than 1.0 × 10⁻⁶. -3 In a vacuum furnace, heat to 550°C and maintain for 1 hour, then cool to room temperature and remove.

[0063] Example 1

[0064] This embodiment 1 provides a method for cleaning an accelerator vacuum chamber, the vacuum chamber having an inner diameter of 450 mm and a wall thickness of 5 mm. The cleaning method for the vacuum chamber includes:

[0065] Step 1: Use a high-pressure water gun to rinse the inner wall of the vacuum chamber to remove the yellow powdery contaminants adhering to the inner wall, and then place the vacuum chamber in the natural environment to dry.

[0066] Step 2: Mechanically polish the inner wall of the vacuum chamber to remove adhering metal particles. For flange surfaces with contaminants on precision metal cutting edges, apply stainless steel passivation paste (a composite paste mainly composed of nitric acid, hydrofluoric acid, and corrosion inhibitors) to the flange surface to avoid mechanical damage to the cutting edges. After standing for 30 minutes, rinse with a high-pressure water gun until all metal particles are completely removed.

[0067] Step 3: Place the vacuum chamber (after completing Step 2) into an ultrasonic bath for ultrasonic cleaning for 3 hours to remove chemical residues. After ultrasonic cleaning, transfer the vacuum chamber to a vacuum cleanroom to air dry naturally.

[0068] Step 4: Place the vacuum chamber obtained after step 3 in an area with a vacuum level less than 1×10⁻⁶. -3 In a vacuum furnace of Pa, the temperature is first increased to 550°C at a rate of 5°C / min and maintained at 550°C for 3 hours. Then, the temperature is decreased to 350°C at a rate of 5°C / min. Finally, nitrogen gas is introduced into the vacuum furnace. After the temperature inside the vacuum furnace drops to 80°C, the vacuum chamber is removed from the vacuum furnace.

[0069] Step 5: After cooling the vacuum chamber from Step 4 to room temperature, perform a leak test on the vacuum chamber in a vacuum cleanroom. Once the vacuum chamber is confirmed to be leak-free, install a sealing cap (such as an aluminum blind flange) at its flange port to seal it, and then fill it with high-purity nitrogen to dry it before storage.

[0070] For vacuum chambers with leaks, the location of the leaks is identified. The leaks are then repaired by welding. After welding, the weld seam is polished, and the area is re-inspected to confirm the leaks have been eliminated. The vacuum chamber is then ultrasonically cleaned again. After ultrasonic cleaning and drying, the vacuum chamber is transferred to a vacuum level less than 1×10⁻⁶. -3 In a vacuum furnace of Pa, the temperature is first raised to 550°C at a rate of 5°C / min and held at 550°C for 1 hour. Then, the temperature is lowered to 350°C at a rate of 5°C / min. Finally, high-purity nitrogen is introduced into the vacuum furnace. After the temperature inside the vacuum furnace drops to 80°C, the vacuum chamber is removed from the vacuum furnace. A sealing cap (such as an aluminum blind flange) is installed on the flange port of the vacuum chamber to seal it, and high-purity nitrogen is introduced to dry it for storage.

[0071] Example 2

[0072] This embodiment 2 provides a cleaning method for an accelerator vacuum chamber, which consists of two circular tubes and a rectangular cross-section tube. The inner diameter of the circular tubes is 150 mm, and the cross-sectional dimensions of the rectangular tube are 138 mm × 36 mm. The wall thickness of both the circular and rectangular tubes is 3 mm. The cleaning method for this vacuum chamber includes:

[0073] Step 1: Use a high-pressure water gun to rinse the inner wall of the vacuum chamber to remove the yellow powdery contaminants adhering to the inner wall, and then place the vacuum chamber in the natural environment to dry.

[0074] Step 2: Add stainless steel passivation paste to deionized water according to the specified ratio to prepare a cleaning solution with a mass concentration of 3.05%. Before pickling, seal all openings of the vacuum chamber except for one filling port. Then, pour the cleaning solution into the vacuum chamber, ensuring that the inner surface of the vacuum chamber is completely wetted by the cleaning solution. After filling, allow the chamber to stand at room temperature for pickling for a total of 24 hours. To enhance the cleaning effect, prevent the re-adhesion of contaminants, and promote deep cleaning, gently shake the vacuum chamber every 2 hours during the pickling process, using fluid shear force to effectively desorb the metal particles adhering to the inner surface.

[0075] For flange faces with precision metal cutting edges that contain contaminants, to avoid mechanical damage to the cutting edges, apply stainless steel passivation paste (a composite paste whose main components are nitric acid, hydrofluoric acid and corrosion inhibitors) to the flange face for synergistic treatment. After standing for 30 minutes, rinse with a high-pressure water gun to ensure that metal particles are completely removed.

[0076] Step 3: Place the vacuum chamber (after completing Step 2) into an ultrasonic bath for ultrasonic cleaning for 3 hours to remove chemical residues. After ultrasonic cleaning, transfer the vacuum chamber to a vacuum cleanroom to air dry naturally.

[0077] Step 4: Place the vacuum chamber obtained after step 3 in an area with a vacuum level less than 1×10⁻⁶. -3 In a vacuum furnace of Pa, the temperature is first raised to 550°C at a rate of 4°C / min and held at 550°C for 3 hours. Then, the temperature is lowered to 350°C at a rate of 4°C / min. Finally, nitrogen gas is introduced into the vacuum furnace. After the temperature inside the vacuum furnace drops to 80°C, the vacuum chamber is removed from the vacuum furnace.

[0078] Step 5: After cooling the vacuum chamber from Step 4 to room temperature, perform a leak test on the vacuum chamber in a vacuum cleanroom. Once the vacuum chamber is confirmed to be leak-free, install a sealing cap (such as an aluminum blind flange) at its flange port to seal it, and then fill it with high-purity nitrogen to dry it before storage.

[0079] For vacuum chambers with leaks, the location of the leaks is identified. The leaks are then repaired by welding. After welding, the weld seam is polished, and the area is re-inspected to confirm the leaks have been eliminated. The vacuum chamber is then ultrasonically cleaned again. After ultrasonic cleaning and drying, the vacuum chamber is transferred to a vacuum level less than 1×10⁻⁶. -3 In a vacuum furnace, the temperature is first increased to 550°C at a rate of 4°C / min and held at 550°C for 1 hour. Then, the temperature is decreased to 350°C at a rate of 4°C / min. Finally, nitrogen is introduced into the vacuum furnace. After the temperature inside the vacuum furnace drops to 80°C, the vacuum chamber is removed from the vacuum furnace. A sealing cap (such as an aluminum blind plate) is installed on the flange port of the vacuum chamber to seal it, and high-purity nitrogen is introduced to dry it for storage.

[0080] Example 3

[0081] This embodiment 3 provides a cleaning method for an accelerator vacuum chamber. This cleaning method is used to clean a bellows with a wall thickness of 0.3 mm and an inner diameter of 150 mm. The cleaning method for the vacuum chamber includes:

[0082] Step 1: Use a high-pressure water gun to rinse the inner wall of the corrugated pipe to remove the yellow powdery contaminants adhering to the inner wall, and then place the vacuum chamber in the natural environment to dry.

[0083] Step 2: Add stainless steel passivation paste to deionized water according to the specified ratio to prepare a cleaning solution with a mass concentration of 3.05%. Before pickling, seal all openings of the bellows except for one filling port. Then, pour the cleaning solution into the bellows, ensuring that the inner surface of the bellows is completely wetted. After filling, allow the bellows to stand at room temperature for pickling for a total of 24 hours. To enhance the cleaning effect, prevent re-adhesion of contaminants, and promote deep cleaning, gently shake the vacuum chamber every 2 hours during the pickling process, using fluid shear force to effectively desorb the metal particles adhering to the inner surface.

[0084] For flange faces with precision metal cutting edges that contain contaminants, to avoid mechanical damage to the cutting edges, apply stainless steel passivation paste (a composite paste whose main components are nitric acid, hydrofluoric acid and corrosion inhibitors) to the flange face for synergistic treatment. After standing for 30 minutes, rinse with a high-pressure water gun to ensure that metal particles are completely removed.

[0085] Step 3: Place the corrugated tube from Step 2 into an ultrasonic bath for ultrasonic cleaning for 3 hours to remove chemical residues. After ultrasonic cleaning, transfer the vacuum chamber to a vacuum cleanroom to air dry naturally.

[0086] Step 4: Place the bellows completed in Step 3 in an environment with a vacuum level of less than 1×10⁻⁶. -3 In a vacuum furnace of Pa, the temperature is first increased to 600°C at 3°C / min and held at 600°C for 2.5 hours. Then, the temperature is decreased to 400°C at 3°C / min. Finally, nitrogen gas is introduced into the vacuum furnace. After the temperature inside the vacuum furnace drops to 70°C, the bellows is removed from the vacuum furnace.

[0087] Step 5: After cooling the bellows from Step 4 to room temperature, perform a leak test on the bellows in a vacuum clean room. For bellows confirmed to be leak-free, install a sealing cap (such as an aluminum blind flange) at the flange end and seal it, then fill it with high-purity nitrogen and store it dry.

[0088] For bellows pipes with leaks, the location of the leaks is identified. The leaks are then repaired by welding. After welding, the weld seam is ground and polished as necessary, and the area is re-inspected to confirm the leaks have been eliminated. The bellows is then ultrasonically cleaned again. After ultrasonic cleaning and drying, the vacuum chamber is transferred to a vacuum level less than 1×10⁻⁶. -3 In a vacuum furnace of Pa, the temperature is first increased to 600°C at 3°C / min and held at 600°C for 1 hour. Then, the temperature is decreased to 400°C at 3°C / min. Finally, high-purity nitrogen is introduced into the vacuum furnace. After the temperature inside the vacuum furnace drops to 70°C, the bellows is removed from the vacuum furnace. A sealing cap (such as an aluminum blind flange) is installed on the flange end of the bellows to seal it, and then high-purity nitrogen is introduced to dry it for storage.

[0089] 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 method for cleaning an accelerator vacuum chamber, characterized in that, include: The inner wall of the vacuum chamber is rinsed with high-pressure water and then dried. Perform a deep cleaning on the vacuum chamber; The vacuum cavity, after deep cleaning, is subjected to ultrasonic cleaning. After ultrasonic cleaning, the vacuum cavity is transferred to a vacuum clean room to air dry. After ultrasonic cleaning and drying, the vacuum chamber is placed in a vacuum furnace. It is first heated to a first preset temperature at a first speed, maintained at the first preset temperature for a first preset time, and then cooled to a second preset temperature at a second speed. Finally, nitrogen gas is introduced into the vacuum furnace. After the temperature inside the vacuum furnace drops to a third preset temperature, the vacuum chamber is removed from the vacuum furnace. Wherein, the first speed ranges from 3℃ / min to 5℃ / min, the first preset temperature ranges from 500℃ to 600℃, the first preset time ranges from 2.5h to 3.5h, the second speed ranges from 3℃ / min to 5℃ / min, the second preset temperature ranges from 300℃ to 400℃, and the third preset temperature ranges from no more than 80℃.

2. The cleaning method for the accelerator vacuum cavity according to claim 1, characterized in that, The first speed is 5℃ / min, the first preset temperature is 550℃, the first preset time is 3h, the second speed is 5℃ / min, the second preset temperature is 350℃, and the third preset temperature is 80℃.

3. The cleaning method for the accelerator vacuum cavity according to claim 1, characterized in that, The step of performing deep cleaning on the vacuum cavity includes: The inner wall of the vacuum cavity is mechanically polished, or the inner wall of the vacuum cavity is acid-washed.

4. The cleaning method for the accelerator vacuum cavity according to claim 3, characterized in that, The step of acid washing the inner wall of the vacuum cavity includes: The vacuum cavity is cleaned by filling it with a cleaning solution; wherein the cleaning solution is prepared from stainless steel passivation paste and the mass concentration of the cleaning solution is 3%~3.5%.

5. The cleaning method for the accelerator vacuum cavity according to claim 3, characterized in that, The step of performing deep cleaning on the vacuum cavity further includes: Apply stainless steel passivation paste to the flange surface of the vacuum chamber, and after a second preset time, wash off the stainless steel passivation paste.

6. The cleaning method for the accelerator vacuum cavity according to claim 1, characterized in that, After the step of removing the vacuum chamber from the vacuum furnace, the method further includes: After the vacuum chamber has cooled to room temperature, a leak test is performed on the vacuum chamber in the vacuum clean room.

7. The cleaning method for the accelerator vacuum cavity according to claim 6, characterized in that, After leak testing of the vacuum chamber within the vacuum cleanroom, the process further includes: If there are no leaks in the vacuum chamber, a sealing cap is installed at the flange port of the vacuum chamber, and nitrogen is introduced for drying and storage. If a leak is found in the vacuum chamber, the leak is repaired by welding and then re-inspected to confirm that the leak has been eliminated. Next, the vacuum chamber with the leak eliminated is ultrasonically cleaned.

8. The cleaning method for an accelerator vacuum cavity according to any one of claims 1 to 7, characterized in that, The inner diameter of the vacuum chamber is 40mm~500mm, and the wall thickness of the vacuum chamber is 0.3mm~5mm.

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