Strip NEG pump for a particle accelerator and method of use

Abstract

The application discloses a strip type NEG (Non Evaporable Getter) pump for a particle accelerator and a use method thereof. The pump comprises a getter assembly, a fixing part, a vacuum flange and an electrode. One end of the getter assembly is provided with the fixing part, the fixing part is fixedly connected with one side of the vacuum flange, the other side of the vacuum flange is provided with the electrode, and the getter assembly is electrically connected with the electrode. The getter assembly comprises two or more getter strips, each getter strip is arranged side by side and fixedly connected with the fixing part at one end, and a gap is reserved between two adjacent getter strips. The use method is that the strip type NEG pump is inserted into a vacuum chamber along the axial direction of the vacuum chamber and then fixedly installed, each getter strip is parallel to the axis of the vacuum chamber, the vacuum flange is fixedly installed with the side wall of the vacuum chamber, and the electrode is externally connected with a power supply device. The application can effectively improve the uniformity of vacuum distribution, maintain a high vacuum degree, avoid misfiring of a beam, has a simple structure, is convenient to install, and can be adapted to the installation requirements of the accelerator vacuum chamber in a large range.

Description

Technical Field

[0001] This invention relates to the field of particle accelerator technology, and in particular to a strip-type NEG intake pump for particle accelerators and its usage method. Background Technology

[0002] The vacuum system is the fundamental engineering component of a particle accelerator. The beam can only maintain a sufficient lifetime and be continuously accumulated and accelerated to achieve the designed energy and flux intensity when operating in a vacuum environment. However, in practical applications, accelerated particles often interact with residual gas in the vacuum, leading to a decrease in beam lifetime and causing beam instability and detector background noise. Therefore, the primary goal of the vacuum system is to obtain and maintain a reasonable vacuum level to ensure stable beam operation. In a particle accelerator, high-energy particles in the storage ring are lost due to interactions with residual gas via Coulomb scattering, nuclear scattering, and bremsstrahlung. Therefore, to maintain a long beam lifetime, the vacuum level required in the vacuum chamber is extremely high, typically needing to reach 10⁻⁷ to 10⁻⁸ Pa.

[0003] Currently, one of the challenges in designing storage ring vacuum systems is achieving the dynamic vacuum requirements during beam operation. In storage ring vacuum systems, besides thermal outgassing of the vacuum material, the main cause of pressure rise is photon desorption caused by synchrotron radiation striking the inner surface of the vacuum chamber. In high-current electron storage rings, electrons generate synchrotron radiation along the tangential direction during their bending motion. High-energy photons striking the vacuum chamber and photon absorber cause a temperature rise. The gas load caused by synchrotron radiation is 1-2 orders of magnitude greater than the thermal outgassing load of typical materials. To reduce the gas load, it is necessary to improve the cleanliness of the vacuum chamber's inner wall, reduce the outgassing caused by photoelectron bombardment of the photodetector wall, and employ a special vacuum structure design, utilizing distributed or centralized pumping methods to improve the pumping efficiency of the vacuum system to meet the vacuum requirements of the beam lifetime.

[0004] In current particle accelerators, ultra-high vacuum is primarily achieved and maintained through discretely distributed vacuum pumps, such as sputtering ion pumps, titanium sublimation pumps, and non-evaporable getter pumps. This pumping method creates a certain longitudinal pressure gradient within the vacuum chamber; that is, the vacuum level is higher and more stable near the pumps, and lower and less stable further away. Particle accelerators are typically very large, and due to space constraints, the number of vacuum pumps must be minimized, meaning the spacing between pumps is often large. Furthermore, accelerator vacuum chambers are usually slender pipes with low conductance; typical accelerator vacuum chambers include variable cross-section stainless steel chambers, circular cross-section copper chambers, and elliptical cross-section insert chambers. Therefore, their pressure gradients are often high, which can severely impact beam lifetime and stability.

[0005] In practice, it has been proven that coating the inner wall of a vacuum chamber with a NEG thin film typically increases the vacuum level by 1 to 2 orders of magnitude compared to a vacuum chamber without coating. By adsorbing residual gas within the vacuum chamber through the NEG film, distributed pumping is achieved, transforming the vacuum chamber from a source of outgassing into a "vacuum pump" with pumping capabilities. In addition, the NEG film also reduces the outgassing rate on the inner surface of the vacuum chamber and decreases the secondary electron yield (SEY) on the inner surface. Therefore, obtaining a high-quality NEG film is a key factor in achieving a good vacuum in a slender vacuum chamber.

[0006] However, NEG films are typically only about 1 micrometer thick, with limited adsorption capacity. As the current intensity accumulates, the pumping speed of the NEG film approaches zero. Therefore, inventing a strip-type NEG pump with a large adsorption capacity that can be installed in a small vacuum chamber would enable the accelerator to obtain a higher vacuum level and a more uniform vacuum distribution. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a strip-type NEG suction pump for particle accelerators. This suction pump can effectively improve the uniformity of vacuum distribution in the vacuum chamber of particle accelerators and maintain a high vacuum level. It can also avoid beam misfiring. Its structure is simple and easy to install, and it can adapt to the installation requirements of various vacuum chamber structures of accelerators in a wide range.

[0008] Another object of the present invention is to provide a method of using the strip-type NEG intake pump for the above-mentioned particle accelerator.

[0009] The technical solution of this invention is as follows: a strip-type NEG suction pump for a particle accelerator, comprising a suction assembly, a fixing part, a vacuum flange, and an electrode. One end of the suction assembly is provided with the fixing part, which is fixedly connected to one side of the vacuum flange. The other side of the vacuum flange is provided with an electrode, and the suction assembly is also electrically connected to the electrode. The suction assembly includes two or more suction strips, each arranged side-by-side with one end fixedly connected to the fixing part, with a gap between adjacent suction strips. As the core structure of the entire strip-type NEG suction pump, the suction assembly is composed of two or more long, narrow suction strips. This design better adapts to the characteristic that the vacuum chamber in a particle accelerator is typically a small-diameter, slender pipe. The suction strips can be laid in a straight line within the vacuum chamber, forming a linear vacuum pumping pattern. This changes the existing point-distribution method of vacuum pumps in vacuum chambers. Combined with the NEG film layer on the inner wall of the vacuum chamber, this improves the uniformity of vacuum distribution within the vacuum chamber and maintains a high vacuum level. The suction assembly is connected to the vacuum flange via a fixing part. During use, it can be quickly inserted into the vacuum chamber and then fixed in place via the vacuum flange, facilitating maintenance operations such as disassembly and replacement of the vacuum chamber. Furthermore, the gap between two adjacent suction strips can be a slit approximately 3.5mm wide. When the strip-type NEG suction pump is installed inside the vacuum chamber, this slit effectively prevents the beam from accidentally striking the pump and causing a large amount of gas release.

[0010] The air intake strip includes a support strip, air intake plates, and a cover plate. The support strip is a long strip-shaped box structure with an opening on one side. The cover plate covers the opening of the support strip, and a hollow installation space is formed between the support strip and the cover plate. Multiple air intake plates are arranged in layers in the installation space.

[0011] The suction plate is perforated, and ceramic heating wires are distributed within it. Copper wires are connected to the outside of the ceramic heating wires and then to electrodes. The distribution of the ceramic heating wires within the suction plate can be adjusted according to the actual manufacturing process of the suction plate.

[0012] Within the suction strip, there are multiple sets of suction plates, with each set of plates connected end-to-end. Four suction plates form a group, and the four plates within the same group are stacked. Adjacent sets of suction plates are connected end-to-end. Since the vacuum chamber of a particle accelerator is generally a long, thin pipe, and different vacuum chambers may have different lengths, processing and installing the suction plates in groups facilitates manufacturing and installation, allows for flexible application to different vacuum chambers, and avoids compromising structural stability due to excessive length.

[0013] In the support bar, the sides parallel to the long axis of the support bar are the bottom surface, the first long side surface, and the second long side surface, respectively, and the sides perpendicular to the long axis of the support bar are the first end surface and the second end surface, respectively.

[0014] The bottom surfaces of the cover plate and the support strip are arranged opposite each other, and each suction plate is arranged parallel between the bottom surfaces of the cover plate and the support strip;

[0015] The bottom surface, first long side, second long side, and cover plate of the support strip all adopt a hollow structure. The hollow structure design can effectively ensure the pumping speed of the suction plate.

[0016] The air intake strip is also provided with an outer frame. On the outer frame, the two sides parallel to the bottom surface of the cover plate and the support strip are also hollowed out. The two sides parallel to the first long side and the second long side are provided with outward protruding mounting strips. Each mounting strip is fixedly connected to the fixing part. The two sides parallel to the first end face and the second end face are the end faces of the outer frame.

[0017] The fixing part includes a flange connector, a suction strip connector and an auxiliary support. One end of the flange connector is fixedly connected to the vacuum flange, and the other end of the flange connector is fixedly connected to the suction strip connector.

[0018] The air intake strip connector has a bracket structure and is provided with multiple mounting strips extending toward the air intake strip. Each mounting strip is fixedly connected to a mounting protrusion on the air intake strip.

[0019] An auxiliary support is provided between the air intake strip connector and the outer frame end face. The two opposite end faces of the auxiliary support abut against the air intake strip connector and the outer frame end face, respectively.

[0020] The suction strip connector has multiple mounting holes distributed on the mounting support, and correspondingly, the suction strip mounting protrusion also has multiple mounting holes distributed on it.

[0021] The principle of the strip-type NEG getter pump used in the aforementioned particle accelerator is as follows: Addressing the elongated, tubular shape of the vacuum chamber in particle accelerators and the uneven vacuum caused by the point-like distribution of existing vacuum pumps, a novel strip-type NEG getter pump was designed. Its core structure consists of two or more elongated getter strips laid straight within the vacuum chamber, forming a linear vacuum pattern. Combined with the NEG film layer on the inner wall of the vacuum chamber, this improves the uniformity of the vacuum distribution and maintains a high vacuum level. Slits are left between adjacent getter strips to effectively prevent beam misfires and subsequent large-scale gas release, thus ensuring the normal and effective operation of the strip-type NEG getter pump. This strip-type NEG getter pump can be rapidly heated and activated by an external power supply. Its simple and convenient operation allows for widespread application in the particle accelerator field.

[0022] The present invention discloses a method for using a strip-type NEG suction pump for a particle accelerator, specifically comprising: inserting the strip-type NEG suction pump into the vacuum chamber along the axial direction of the vacuum chamber in the particle accelerator and fixing it in place; each suction strip on the suction assembly being parallel to the axis of the vacuum chamber; the vacuum flange being fixedly installed to the side wall of the vacuum chamber; and an external power supply device being connected to the electrode.

[0023] When the above-mentioned strip-type NEG suction pump is used in a vacuum chamber, the suction plate is activated in the following way:

[0024] By setting ceramic heating wires inside the intake plates, the ceramic heating wires on each intake plate are connected in series and then connected to the electrodes by copper wires. The outer periphery of the copper wires is insulated and shielded by ceramic rings.

[0025] The power supply device supplies power to the suction pump through electrodes. After power is applied, the copper wire conducts electricity, which heats the ceramic heating wires in each suction plate, thereby activating the suction plate and enabling it to have good suction function.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] The strip-type NEG suction pump used in this particle accelerator has a cylindrical structure designed as a strip structure, consisting of two or more long strip suction bars with gaps between adjacent suction bars. This effectively improves the uniformity of vacuum distribution in the particle accelerator vacuum chamber and maintains a high vacuum level. It also avoids beam misfiring. Its structure is simple and easy to install, and it can adapt to the installation requirements of various vacuum chamber structures in accelerators.

[0028] The strip-type NEG suction pump used in this particle accelerator has a simple structure and is easy to use. The suction assembly is connected to the vacuum flange via a fixing part. During use, it can be quickly inserted into the vacuum chamber and fixed in place via the vacuum flange, facilitating maintenance operations such as disassembly, assembly, and replacement of the vacuum chamber. Simultaneously, the suction plate can be quickly heated and activated via an external power supply. Its simple and convenient use makes it suitable for widespread application in the field of particle accelerators. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the NEG belt-type suction pump.

[0030] Figure 2 for Figure 1 A plan view in direction A.

[0031] Figure 3 for Figure 2 View from direction B.

[0032] Figure 4 for Figure 2The C-direction view.

[0033] Figure 5 This is a partial structural diagram of a single air intake strip.

[0034] Figure 6 for Figure 5 A view from direction D, showing the hollow structure of the bottom surface of the support strip or the cover plate.

[0035] Figure 7 for Figure 6 A schematic diagram of the hollow structure on the first or second long side in the E-direction view.

[0036] Figure 8 for Figure 7 A cross-sectional view of the FF section, and a schematic diagram of the intake plate structure.

[0037] Figure 9 for Figure 7 A cross-sectional view of the GG section, showing the distribution structure of the same group of suction plates between the support strip and the cover plate.

[0038] The components indicated by the reference numerals in the above figures are as follows:

[0039] a is the air intake component, 1 is the gap, 2 is the support strip, 2-1 is the bottom surface, 2-2 is the first long side surface, 2-3 is the second long side surface, 2-4 is the first end face, 3 is the air intake plate, 4 is the cover plate, 5 is the outer frame, and 6 is the mounting protrusion.

[0040] b is the fixing part, 7 is the flange connector, 8 is the air intake strip connector, 8-1 is the mounting strip, 8-2 is the mounting hole, and 9 is the auxiliary support.

[0041] c is a vacuum flange;

[0042] d represents the electrode. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0044] Example

[0045] This embodiment provides a strip-type NEG suction pump for a particle accelerator and its usage method.

[0046] like Figures 1 to 4As shown, the strip-type NEG getter pump used in this particle accelerator includes a getter assembly a, a fixing part b, a vacuum flange c, and an electrode d. One end of the getter assembly has a fixing part, which is fixedly connected to one side of the vacuum flange. The other side of the vacuum flange has an electrode, and the getter assembly is also electrically connected to the electrode. The getter assembly includes two or more getter strips (two getter strips are used in this embodiment), each getter strip is arranged side-by-side and fixedly connected to the fixing part at one end, with a gap 1 between adjacent getter strips. As the core structure of the entire strip-type NEG getter pump, the getter assembly is composed of two or more long strips, which can better adapt to the characteristic that the vacuum chamber in a particle accelerator is usually a slender pipe with a small diameter. The getter strips can be laid in a straight strip within the vacuum chamber, forming a linear vacuum pumping pattern, changing the point-distribution method of vacuum pumps in existing vacuum chambers. Combined with the NEG film layer on the inner wall of the vacuum chamber, this helps improve the uniformity of vacuum distribution within the vacuum chamber and maintain a high vacuum level. The suction assembly is connected to the vacuum flange via a fixing part. During use, it can be quickly inserted into the vacuum chamber and then fixed in place via the vacuum flange, facilitating maintenance operations such as disassembly and replacement of the vacuum chamber. Furthermore, the gap between two adjacent suction strips can be a slit approximately 3.5mm wide. When the strip-type NEG suction pump is installed inside the vacuum chamber, this slit effectively prevents the beam from accidentally striking the pump and causing a large amount of gas release.

[0047] like Figures 5 to 9 As shown, the suction strip includes a support strip 2, suction plates 3, and a cover plate 4. The support strip has a long, box-like structure with an opening on one side. The cover plate covers the opening of the support strip, forming a hollow installation space between the support strip and the cover plate. Multiple stacked suction plates are arranged within this installation space. Figure 8 As shown, the suction plate is perforated, and ceramic heating wires (not shown in the figure) are distributed inside the suction plate. Copper wires are connected to the outside of the ceramic heating wires and then to the electrodes. The distribution of the ceramic heating wires within the suction plate can be adjusted according to the actual manufacturing process of the suction plate.

[0048] Inside the air intake strip, there are multiple sets of air intake plates, with each set of four air intake plates connected end to end. Within the same set, the four air intake plates are stacked (e.g., ...). Figure 9 As shown), adjacent groups of gas-absorbing plates are connected end-to-end. Since the vacuum chambers of particle accelerators are generally long and narrow tubes, and different vacuum chambers may have different lengths, the gas-absorbing plates are processed and installed in groups. This facilitates processing and installation, allows for flexible application to different vacuum chambers, and avoids affecting structural stability due to excessive length. In the support bar, the sides parallel to the long axis of the support bar are the bottom surface 2-1, the first long side surface 2-2, and the second long side surface 2-3, respectively. The sides perpendicular to the long axis of the support bar are the first end surface 2-4 (as shown). Figure 5(as shown) and the second end face (not shown in the figure); the bottom surfaces of the cover plate and the support strip are opposite each other, and each suction plate is arranged parallel between the bottom surfaces of the cover plate and the support strip; the bottom surface of the support strip, the first long side surface, the second long side surface and the cover plate all adopt a hollow structure (as shown in the figure). Figure 6 and Figure 7 As shown in the figure, the hollow structure design can effectively ensure the pumping speed of the suction plate.

[0049] like Figure 1 As shown or Figure 2 As shown, the air intake strip is also provided with an outer frame 5. On the outer frame, the two sides parallel to the bottom surface of the cover plate and the support strip are also hollowed out. The two sides parallel to the first long side and the second long side are provided with outward protruding mounting strips 6. Each mounting strip is fixedly connected to the fixing part. The two sides parallel to the first end face and the second end face are the end faces of the outer frame.

[0050] like Figure 1 or Figure 2 As shown, the fixing part includes a flange connector 7, a suction strip connector 8, and an auxiliary support 9. One end of the flange connector is fixedly connected to the vacuum flange, and the other end is fixedly connected to the suction strip connector. The suction strip connector has a bracket structure with multiple mounting supports 8-1 extending towards the suction strip. Each mounting support corresponds to a mounting protrusion on the suction strip and is fixedly connected. An auxiliary support is also provided between the suction strip connector and the end face of the outer frame. The two opposite end faces of the auxiliary support abut against the suction strip connector and the end face of the outer frame, respectively. Multiple mounting holes 8-2 are distributed on the mounting supports of the suction strip connector, and correspondingly, multiple mounting holes are also distributed on the mounting protrusions of the suction strip.

[0051] The principle of the strip-type NEG getter pump used in the aforementioned particle accelerator is as follows: Addressing the elongated, tubular shape of the vacuum chamber in particle accelerators and the uneven vacuum caused by the point-like distribution of existing vacuum pumps, a novel strip-type NEG getter pump was designed. Its core structure consists of two or more elongated getter strips laid straight within the vacuum chamber, forming a linear vacuum pattern. Combined with the NEG film layer on the inner wall of the vacuum chamber, this improves the uniformity of the vacuum distribution and maintains a high vacuum level. Slits are left between adjacent getter strips to effectively prevent beam misfires and subsequent large-scale gas release, thus ensuring the normal and effective operation of the strip-type NEG getter pump. This strip-type NEG getter pump can be rapidly heated and activated by an external power supply. Its simple and convenient operation allows for widespread application in the particle accelerator field.

[0052] The specific method for using the strip-type NEG getter pump in the aforementioned particle accelerator is as follows: after inserting the strip-type NEG getter pump into the vacuum chamber along the axial direction of the vacuum chamber in the particle accelerator, it is fixedly installed. Each getter strip on the getter assembly is parallel to the axis of the vacuum chamber. The vacuum flange is fixedly installed to the side wall of the vacuum chamber. An external power supply device is connected to the electrode.

[0053] When the NEG strip-type suction pump is used in a vacuum chamber, the suction plate is activated in the following manner:

[0054] By setting ceramic heating wires inside the intake plates, the ceramic heating wires on each intake plate are connected in series and then connected to the electrodes by copper wires. The outer periphery of the copper wires is insulated and shielded by ceramic rings.

[0055] The power supply device supplies power to the suction pump through electrodes. After power is applied, the copper wire conducts electricity, which heats the ceramic heating wires in each suction plate, thereby activating the suction plate and enabling it to have good suction function.

[0056] As described above, the present invention can be well implemented. The above embodiments are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention; that is, all equivalent changes and modifications made in accordance with the content of the present invention are covered by the scope of protection claimed in the claims of the present invention.

Claims

1. A strip-type NEG intake pump for a particle accelerator, characterized in that, It includes a suction assembly, a fixing part, a vacuum flange, and an electrode. One end of the suction assembly is provided with a fixing part, which is fixedly connected to one side of the vacuum flange. The other side of the vacuum flange is provided with an electrode, and the suction assembly is also electrically connected to the electrode. The suction assembly includes two or more suction strips, each suction strip is arranged side by side and one end is fixedly connected to the fixing part, and a gap is left between two adjacent suction strips.

2. The strip-type NEG intake pump for a particle accelerator according to claim 1, characterized in that, The air intake strip includes a support strip, air intake plates, and a cover plate. The support strip is a long strip-shaped box structure with an opening on one side. The cover plate covers the opening of the support strip, and a hollow installation space is formed between the support strip and the cover plate. Multiple air intake plates are arranged in layers in the installation space.

3. The strip-type NEG intake pump for a particle accelerator according to claim 2, characterized in that, The air intake plate is hollow, and ceramic heating wires are distributed inside the air intake plate. Copper wires are connected to the outside of the ceramic heating wires and are connected to the electrodes through the copper wires.

4. The strip-type NEG intake pump for a particle accelerator according to claim 2, characterized in that, The air intake strip contains multiple sets of air intake plates, with each set of air intake plates connected end to end. Every four air intake plates form a set, and the four air intake plates in the same set are stacked. Adjacent sets of air intake plates are connected end to end in series.

5. A strip-type NEG intake pump for a particle accelerator according to claim 2, characterized in that, In the support bar, the sides parallel to the long axis of the support bar are the bottom surface, the first long side surface, and the second long side surface, respectively, and the sides perpendicular to the long axis of the support bar are the first end surface and the second end surface, respectively. The bottom surfaces of the cover plate and the support strip are arranged opposite each other, and each suction plate is arranged parallel between the bottom surfaces of the cover plate and the support strip; The bottom surface, first long side, second long side, and cover plate of the support strip all adopt a hollow structure.

6. A strip-type NEG intake pump for a particle accelerator according to claim 5, characterized in that, The air intake strip is also provided with an outer frame. On the outer frame, the two sides parallel to the bottom surface of the cover plate and the support strip are also hollowed out. The two sides parallel to the first long side and the second long side are provided with outward protruding mounting strips. Each mounting strip is fixedly connected to the fixing part. The two sides parallel to the first end face and the second end face are the end faces of the outer frame.

7. A strip-type NEG intake pump for a particle accelerator according to claim 6, characterized in that, The fixing part includes a flange connector, a suction strip connector and an auxiliary support. One end of the flange connector is fixedly connected to the vacuum flange, and the other end of the flange connector is fixedly connected to the suction strip connector. The air intake strip connector has a bracket structure and is provided with multiple mounting strips extending toward the air intake strip. Each mounting strip is fixedly connected to a mounting protrusion on the air intake strip. An auxiliary support is provided between the air intake strip connector and the outer frame end face. The two opposite end faces of the auxiliary support abut against the air intake strip connector and the outer frame end face, respectively.

8. A strip-type NEG intake pump for a particle accelerator according to claim 7, characterized in that, The suction strip connector has multiple mounting holes distributed on the mounting support, and correspondingly, the suction strip mounting protrusion also has multiple mounting holes distributed on it.

9. A method of using the strip-type NEG intake pump for the particle accelerator according to any one of claims 1 to 8, characterized in that, Along the axial direction of the vacuum chamber in the particle accelerator, the strip-type NEG suction pump is inserted into the vacuum chamber and fixedly installed. Each suction strip on the suction assembly is parallel to the axis of the vacuum chamber. The vacuum flange is fixedly installed to the side wall of the vacuum chamber. An external power supply device is connected to the electrode.

10. The method of using the strip-type NEG intake pump for a particle accelerator according to claim 9, characterized in that, When using a strip-type NEG suction pump in a vacuum chamber, the suction vanes are activated in the following manner: By setting ceramic heating wires inside the intake plates, the ceramic heating wires on each intake plate are connected in series and then connected to the electrodes by copper wires. The outer periphery of the copper wires is insulated and shielded by ceramic rings. The power supply device supplies power to the suction pump through electrodes. After power is applied, the copper wire conducts electricity, which heats the ceramic heating wires in each suction plate, thereby activating the suction plate and enabling it to have good suction function.

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