A thermostat cold mass assembly

Abstract

This invention discloses a cryostat cold mass assembly, including a cryostat base plate, a cold mass support unit, and a support assembly. The cold mass support unit is slidably fixed to the top of the cryostat base plate via the support assembly. At room temperature, the cold mass support unit is pre-offset relative to the cryostat base plate, and the pre-offset amount is the amount of material contraction at low temperatures. In this invention, by pre-offsetting the cold mass support unit at room temperature, the entire cryostat returns to the centerline position when it contracts at low temperatures, thereby ensuring that the centerline does not shift at low temperatures and guaranteeing alignment at low temperatures.

Description

Technical Field

[0001] This invention relates to the field of low-temperature superconducting accelerator technology, and more specifically to a cryostat cold mass assembly. Background Technology

[0002] As the most important component of a superconducting particle accelerator, the cryostat provides liquid helium and mechanical support for the superconducting cavity and superconducting magnets, realizes and maintains the temperature and pressure environment required for the normal operation of superconducting components, and forms thermal shielding and thermal isolation to reduce the overall thermal load of the system. Its performance directly determines the investment and operating costs of the entire cryogenic accelerator system.

[0003] The cold mass of the cryostat consists of several superconducting cavities and superconducting magnets connected in series. To ensure particle acceleration performance, the relative positions of each superconducting cavity and superconducting magnet must be kept fixed. At room temperature, the position of the cold mass can be collimated, but at low temperatures, the material will shrink, and the amount of shrinkage varies depending on the material. The low-temperature collimation problem of the superconducting cavities and superconducting magnets within the cold mass is the key to the performance of the cryostat.

[0004] Patent document CN 205175896 U discloses an adjustable coupling connector for a spectrometer and a cryostat. The adjustable coupling connector includes a bracket comprising an upper support plate, a lower support plate, and a support column. A cavity for placing a spectrometer sample cup is formed between the upper and lower support plates. The lower support plate has a base with an upward-facing groove for placing the spectrometer sample cup on its upper surface. The upper support plate has insertion holes penetrating both end faces and a reserved observation hole. A directional fine-tuning device is provided around the insertion holes on the upper support plate, used to clamp and adjust the position of the cold head within the cavity. A rear baffle is provided on the side of the bracket, its top connected to the upper support plate and its bottom connected to the lower support plate, with an angle connection at the bottom of the rear baffle where it connects to the lower support plate. A flexible material layer is provided at the edge of the insertion holes.

[0005] However, the materials in the superconducting cavity and superconducting magnet will shrink at low temperatures. The amount of shrinkage varies from material to material, which makes it impossible to ensure collimation at low temperatures. Summary of the Invention

[0006] The technical problem to be solved by this invention is how to ensure that the superconducting cavity of the cold mass support is aligned with the superconducting magnet at low temperature.

[0007] The present invention solves the above-mentioned technical problems through the following technical means: a cryostat cold mass assembly, including a cold mass support and multiple superconducting cavities and superconducting magnets connected in series on the cold mass support. The top of the cold mass support unit is provided with matching connectors at both ends connected to the superconducting cavities and superconducting magnets. One end of the superconducting cavity is fixed to one connector, and the other end is slidably engaged with another connector. At low temperature, the superconducting cavity and superconducting magnet move from their sliding engagement end to their fixed end. The center line of the connecting pipe connecting the multiple series-connected superconducting cavities and superconducting magnets forms the beam center. The cold mass support, superconducting cavity, and superconducting magnet are pre-offset from the beam center at room temperature.

[0008] By pre-offsetting the cold mass support, superconducting cavity, and superconducting magnet at room temperature, the entire cold mass assembly can be cooled and contracted at low temperature. At low temperature, the superconducting cavity and superconducting magnet move from their sliding end to their fixed end, ensuring collimation at low temperature.

[0009] As a preferred technical solution, the pre-offset of the cold mass support, the superconducting cavity, and the superconducting magnet are the differences in their dimensions at room temperature and at low temperature, respectively.

[0010] As a preferred technical solution, the cold mass support includes two symmetrically distributed cold mass supports. The connector is fixedly mounted on the top of the cold mass supports. One end of the superconducting cavity is fixedly connected to the cold mass support, and the other end is slidably engaged with the cold mass support. One end of the superconducting magnet is fixedly connected to the cold mass support, and the other end is slidably engaged with the cold mass support. Adjacent superconducting cavities and superconducting magnets are connected to the superconducting cavities through telescopic corrugated pipes.

[0011] By fixing one end of the superconducting cavity and superconducting magnet to a cold mass support and movably connecting the other end, the superconducting cavity, superconducting magnet and their connecting parts can be ensured to shrink and cool at low temperatures.

[0012] As a preferred technical solution, a first connecting plate and a second connecting plate are fixedly connected to both ends of the superconducting cavity, and a connecting member fixed to the top of the cold mass support is adapted to the first connecting plate and the second connecting plate. The connecting member includes a first connecting platform and a second connecting platform. The first connecting plate and the first connecting platform are slidably connected through a support sliding mechanism, and the second connecting plate is connected and fastened to the second connecting platform by bolts.

[0013] As a preferred technical solution, the second connecting plate is a rectangular plate with waist holes on both sides of the top end facing the second connecting platform. A guide post is fixed on the top of the second connecting platform. The waist holes are adapted to the guide post, and the bolt is located at the center of the line connecting the two waist holes.

[0014] As a preferred technical solution, the supporting sliding mechanism includes a lower sliding plate and a lower fixed plate. The first connecting plate is a U-shaped plate, with its large end face fixedly connected to the superconducting cavity. Both small end faces of the first connecting plate are formed with mounting holes adapted to the lower sliding plate. The lower sliding plate is fixedly connected in the mounting holes. The lower fixed plate is fixedly embedded in the top of the cold mass support. The lower sliding plate slides in cooperation with the lower fixed plate through multiple spheres. The radius of the spheres is greater than the sum of the cold contraction of the first connecting plate, the superconducting cavity, and the second connecting plate at low temperature.

[0015] By setting the lower sliding plate, the lower fixed plate, and the sphere between them, sliding support between the superconducting cavity and the cold mass support can be achieved. By setting the radius of the sphere to be greater than the sum of the cold shrinkage of the first connecting plate, the superconducting cavity, and the second connecting plate at low temperature, it can be ensured that the first connecting plate will not detach from the first connecting platform during cold shrinkage, and automatic reset can be achieved at room temperature.

[0016] As a preferred technical solution, the superconducting magnet is fixedly connected to a third connecting plate and a fourth connecting plate at both ends, and the top of the cold mass support is fixed with a third connecting platform and a fourth connecting platform that are adapted to the third connecting plate and the fourth connecting plate. The fourth connecting plate is fixedly connected to the fourth connecting platform, and the third connecting plate is slidably connected to the third connecting platform through a support sliding mechanism.

[0017] As a preferred technical solution, the system also includes a cryogenic pipeline. The cryogenic pipeline mounting bracket is fixedly mounted on the top of the cryogenic mass support and provides installation support for the cryogenic pipeline.

[0018] As a preferred technical solution, the cryogenic pipeline includes a main pipe and branch pipes. The main pipe includes a vertical section and a horizontal section. A telescopic corrugated pipe is provided on the vertical section of the main pipe. Multiple branch pipes are connected to the bottom of the horizontal section of the main pipe. A connecting pipe is provided at the top of the superconducting cavity and the superconducting magnet. The branch pipes are respectively connected to the connecting pipes through telescopic corrugated pipes.

[0019] As a preferred technical solution, the telescopic corrugated pipe connecting the branch pipe and the connecting pipe is installed horizontally. The installation of the telescopic corrugated pipe can ensure the movement of the cold mass support, the superconducting cavity and the superconducting magnet during cooling and contraction. Horizontal installation is beneficial to compensate for the large amount of cooling and contraction displacement in the beam direction, thereby maintaining the stability of the pipeline.

[0020] The advantages of this invention are:

[0021] (1) In this invention, by pre-offsetting the cold mass support, superconducting cavity and superconducting magnet at room temperature, the entire cold mass assembly can be cooled and shrunk at low temperature. At low temperature, the superconducting cavity and superconducting magnet move from their sliding end to their fixed end, ensuring collimation at low temperature.

[0022] (2) In this invention, by fixing one end of the superconducting cavity and the superconducting magnet to the cold mass support and movably connecting the other end, the superconducting cavity and the superconducting magnet and their connecting parts can be ensured to shrink and cool at low temperatures.

[0023] (3) In this invention, the sliding support between the superconducting cavity and the cold mass support can be realized by setting the lower sliding plate and the lower fixed plate and the sphere between them. By setting the radius of the sphere to be greater than the sum of the cold shrinkage of the first connecting plate, the superconducting cavity and the second connecting plate at low temperature, it can be ensured that the first connecting plate will not detach from the first connecting platform during cold shrinkage, and automatic reset can be achieved at room temperature.

[0024] (4) In this invention, the telescopic bellows can ensure the movement of the cold mass support, the superconducting cavity and the superconducting magnet during the cold contraction. The horizontal installation is beneficial to compensate for the large amount of cold contraction displacement in the beam direction, thereby maintaining the stability of the pipeline. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of the beam center structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the cold mass support structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0028] Figure 4 A schematic diagram of a support component structure for a thermostat cold mass assembly provided in an embodiment of the present invention;

[0029] Figure 5 A schematic diagram of the cold screen structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0030] Figure 6 A schematic diagram of the valve structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0031] Figure 7 This is a top view schematic diagram of a support component for a thermostat cold mass assembly provided in an embodiment of the present invention;

[0032] Figure 8 A three-dimensional structural diagram of a support component for a thermostat cold mass assembly is provided in an embodiment of the present invention.

[0033] Figure 9 This is a schematic diagram of the first cold screen support structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0034] Figure 10 A schematic diagram of a fixed support structure for a thermostat cold mass assembly provided in an embodiment of the present invention;

[0035] Figure 11 A thermostat cold mass assembly provided in an embodiment of the present invention Figure 10 A schematic diagram of the BB cross-sectional structure;

[0036] Figure 12 This is a schematic diagram of the second cold screen support structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0037] Figure 13 A schematic diagram of a sliding support structure for a thermostat cold mass assembly provided in an embodiment of the present invention;

[0038] Figure 14 A thermostat cold mass assembly provided in an embodiment of the present invention Figure 13 A schematic diagram of the AA cross-sectional structure;

[0039] Figure 15 This is a top view schematic diagram of the cold mass support structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0040] Figure 16 This is a top and side view schematic diagram of the mass support structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0041] Figure 17 This is a schematic diagram of a cryogenic pipeline mounting bracket structure for a thermostat cold mass assembly, provided in an embodiment of the present invention.

[0042] Figure 18 This is a top view schematic diagram of the superconducting cavity structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0043] Figure 19 This is a schematic diagram of a support sliding mechanism for a thermostat cold mass assembly provided in an embodiment of the present invention;

[0044] Figure 20 A schematic diagram of the first connecting plate structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0045] Figure 21 A schematic diagram of the valve structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0046] Figure 22 A schematic diagram of the internal structure of a valve in a thermostat cold mass assembly provided in an embodiment of the present invention;

[0047] Figure 23 A schematic diagram of the cryogenic piping structure of a thermostat cold mass assembly provided in an embodiment of the present invention;

[0048] Figure 24 A schematic diagram of the vacuum chamber structure of a thermostat cold mass assembly is provided for an embodiment of the present invention;

[0049] Reference numerals: 1. Thermostat base plate; 2. Base support; 3. Cold mass bracket; 31. Low-temperature pipeline mounting bracket; 4. Superconducting cavity; 401. First connecting plate; 402. Second connecting plate; 403. Waist hole; 404. Bolt; 405. Support sliding mechanism; 4051. Upper sliding plate; 4052. Upper fixed plate; 4053. Lower sliding plate; 4054. Lower fixed plate; 5. Superconducting magnet; 501. Third connecting plate; 502. Fourth connecting plate; 6. Beam center; 7. Support assembly; 71. Fixed support; 711. Fixed support cylinder; 712. First inner flange at the low-temperature end; 713. First outer flange at the low-temperature end; 714. Inner flange of the first heat sink; 715. Outer flange of the first heat sink; 716. First inner flange at the room temperature end; 717. First outer flange at the room temperature end; 718. First cold shield support; 72. Sliding support; 720 1. Sliding support cylinder; 7202. Second inner flange at low temperature end; 7203. Second outer flange at low temperature end; 7204. Second inner flange for heat sink; 7205. Second outer flange for heat sink; 7206. Second inner flange at room temperature end; 7207. Second outer flange at room temperature end; 7208. Upper slide rail; 7209. Slider; 7210. Second cold shield support; 7211. Bottom slide rail; 73. Connecting parts; 731. First 732. Second connecting platform; 733. Guide column; 734. Third connecting platform; 735. Fourth connecting platform; 8. Cryogenic pipeline; 81. Main pipe; 82. Branch pipe; 9. Cold shield; 10. Vacuum chamber; 101. Connecting port; 1010. Transmission rod; 1011. Universal joint; 1012. Sealing ring; 1013. Limiting ring; 11. Valve; 1101. Baffle plate; 12. Negative pressure protection device. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] See Figures 1 to 6A thermostat with a cold mass assembly includes a thermostat base plate 1, a base support 2, a cold mass support unit, a superconducting cavity 4, a superconducting magnet 5, a beam center 6, a support assembly 7, a cryogenic pipeline 8, a cold shield 9, a vacuum chamber 10, a valve 11, and a negative pressure protection device 12. The vacuum chamber 10 is fixedly connected to the top of the thermostat base plate 1, and a vacuum cavity is provided inside the vacuum chamber 10. The superconducting cavity 4, superconducting magnet 5, beam center 6, support assembly 7, cryogenic pipeline 8, cold shield 9, and valve 11 are all located inside the vacuum cavity. Multiple base supports 2 are fixedly connected to the bottom of the thermostat base plate 1. The bottom support structure is height-adjustable and can be a commercially available component. Its specific structure will not be described in detail. The cold mass support unit is adjustablely mounted on the top of the thermostat base plate 1 via the support assembly 7. The cold mass support unit is provided with mounting cavities for superconducting cavities 4 and superconducting magnets 5. Both superconducting cavities 4 and superconducting magnets 5 can be adjusted and installed in the mounting cavities of the cold mass support unit. One end of the superconducting cavity 4 is fixed to one end of the cold mass support unit, and the other end is clearance-fitted to the other end of the cold mass support unit. The center line of the connecting pipes connecting multiple series-connected superconducting cavities 4 and superconducting magnets 5 forms a beam center 6.

[0052] The cold screen 9 is fixedly connected to the cold mass support unit. Valves 11 are fixed at both ends of the connecting pipe between the superconducting cavity 4 and the superconducting magnet 5. The connecting pipe contains a beam vacuum, within which the ion beam runs. The beam vacuum is opened and closed by opening the valve core of valve 11. The cryogenic pipe 8 is located above the cold screen 9. (See reference...) Figure 24 The negative pressure protection device 12 is fixedly connected to the top of the vacuum chamber 10. One end of the low temperature pipeline 8 is connected to the negative pressure protection device 12, and the other end is connected to the superconducting cavity 4 and the superconducting magnet 5.

[0053] In this embodiment, the superconducting cavity 4 is fixed by a sliding support, allowing it to slide freely during the cooling process. Based on the different coefficients of thermal contraction of the materials on the superconducting cavity 4, the mounting points on both sides are pre-offset in the X and Y directions. At room temperature, the cold mass support unit is pre-offset relative to the beam center 6, and at low temperature, it returns to the beamline position of the beam center 6. At the same time, in the height Z direction, the amount of thermal contraction at low temperature is added to the height direction of the cold mass support unit. At room temperature, the height of the cold mass support unit is higher than the height under normal operation. Thus, at low temperature, the support component 7 contracts according to its own material properties to reach the normal operating height. After the low temperature contraction, the thermostat can automatically achieve the collimation effect.

[0054] See Figure 7 , Figure 8The support assembly 7 includes a fixed support 71 and a sliding support 72; the fixed support 71 includes a fixed support cylinder 711, a first inner flange at the low temperature end 712, a first outer flange at the low temperature end 713, a first inner flange at the first heat sink 714, a first outer flange at the first heat sink 715, a first inner flange at the room temperature end 716, a first outer flange at the room temperature end 717, and a first cold shield support 718.

[0055] See Figure 9 , Figure 10 , Figure 11 The top of the fixed support cylinder 711 is the low-temperature end, and the bottom is the room-temperature end. The top outer wall of the fixed support cylinder 711 is interference-fitted with a first outer flange 713 for the low-temperature end, and the top inner wall is interference-fitted with a first inner flange 712 for the low-temperature end. The first inner flange 712 is connected and secured to the cold mass support unit via reamed bolts. A first outer heat sink flange 715 is fixedly connected to the outer wall of the middle section of the fixed support cylinder 711, and a first inner heat sink flange 714 is fixedly connected to the inner wall. A first cold shield support 718 is fixed to the outer wall of the first outer heat sink flange 715. The first cold shield support 718 supports the cold shield 9 and simultaneously draws cold energy from the cold shield 9, acting as a heat sink and reducing heat leakage from the low-temperature end cold mass support unit. The bottom outer wall of the fixed support cylinder 711 is fixedly connected with… The first outer flange 717 at the room temperature end has a first inner flange 716 at the room temperature end fixedly connected to its bottom inner wall. The first inner flange 716 at the room temperature end is fixedly connected to the thermostat base plate 1 and is positioned by the intermediate pin hole to ensure installation accuracy. It should be noted that the first inner flange 712 at the low temperature end, the first outer flange 713 at the low temperature end, the first inner flange 714 at the first heat sink, the first outer flange 715 at the first heat sink, the first inner flange 716 at the room temperature end, and the first outer flange 717 at the room temperature end are all interference fit with the fixed support cylinder 711. They all maintain relative position stability through the friction of the interference fit and have a load capacity greater than 50KN. The fixed support cylinder 711 is made of G10 / G11 material, which has an extremely low thermal conductivity and can achieve high load capacity and low heat leakage within a limited size.

[0056] See Figure 12 , Figure 13 , Figure 14 The sliding support 72 includes a sliding support cylinder 7201, a second inner flange at the low temperature end 7202, a second outer flange at the low temperature end 7203, a second inner flange at the second heat sink 7204, a second outer flange at the second heat sink 7205, a second inner flange at the room temperature end 7206, a second outer flange at the room temperature end 7207, an upper slide rail 7208, a slider 7209, a second cold shield support 7210, and a bottom slide rail 7211; the length direction of the thermostat base plate 1 is defined as the X direction, the width direction as the Y direction, and the height direction as the Z direction;

[0057] See Figure 8 , Figure 13The thermostat base plate 1 has a bottom slide rail 7211 fixedly connected to its top. The bottom slide rail 7211 is set along the Y direction. A slider 7209 is slidably connected to the bottom slide rail 7211. An upper slide rail 7208 is slidably connected to the top of the slider 7209. The upper slide rail 7208 is set along the X direction. The upper slide rail 7208 is fixedly connected to the sliding support cylinder 7201 through a second inner flange 7206 at the room temperature end. The top of the sliding support cylinder 7201 is the low temperature end, and the bottom is the room temperature end. The outer wall of the top of the sliding support cylinder 7201 is press-fitted with a second outer flange 7203 at the low temperature end, and the inner wall of the top is press-fitted with a second inner flange 7202 at the low temperature end. The second inner flange 7202 at the low temperature end is connected to the bottom of the cold mass support unit through a reamed bolt. The sliding support cylinder 7201 is fastened with a second heat sink outer flange 7205 fixedly connected to the outer wall of the middle section, and a second heat sink inner flange 7204 fixedly connected to the inner wall. A second cold screen support 7210 is fixedly connected to the outer wall of the second heat sink outer flange 7205. The second cold screen support 7210 is used to support the cold screen 9 and obtain cold energy from the cold screen 9, thus acting as a heat sink and reducing heat leakage of the cold mass support unit at the low temperature end. A room temperature end second outer flange 7207 is fixedly connected to the outer wall of the bottom of the sliding support cylinder 7201, and a room temperature end second inner flange 7206 is fixedly connected to the inner wall of the bottom. The sliding support cylinder 7201 is made of G10 / G11 material, which has an extremely low thermal conductivity and can achieve high load-bearing capacity and low heat leakage within a limited size.

[0058] See Figure 15 , Figure 16 , Figure 17The cold mass support unit includes two cold mass support sections, each of which includes two symmetrically arranged cold mass supports 3, namely the left cold mass support 3 and the right cold mass support 3. The four cold mass supports 3 are designated as the first, second, third, and fourth cold mass supports 3 from left to right, respectively, and are the first cold mass support section and the second cold mass support section. The bottom of the first cold mass support section is fixedly connected to two fixed supports 71 and four sliding supports 72. The cold mass support 3 has a rectangular structure, with its Y-direction length greater than its X-direction length. The two fixed supports 71 are fixedly installed at the middle of the two cold mass supports 3, with one fixed support 71 fixedly connected to the bottom left side of the first cold mass support 3 and the other fixed support 71 fixedly connected to the bottom right side of the second cold mass support 3. The two sliding supports 72 are fixedly connected to the bottom right side of the first cold mass support 3 and are symmetrically arranged along the Y-direction centerline of the first cold mass support 3. The second cold mass support section has the same structure as the first cold mass support section. The second cold mass support section includes a third cold mass support 3 and a fourth cold mass support 3 arranged sequentially along the beam center 6 direction. A fixed support 71 is fixedly connected to the center of the bottom left side of the third cold mass support 3 and the center of the bottom right side of the fourth cold mass support 3. Two sliding supports 72 are fixedly connected to the center of the bottom right side of the third cold mass support 3 and the bottom left side of the fourth cold mass support 3, and are symmetrically arranged along the Y-axis centerline of the third cold mass support 3. All four fixed supports 71 are located on the same straight line. The four fixed supports 71 can limit the movement of the four cold mass supports 3. At low temperature, the sliding supports 72 will contract due to cold, resulting in X-axis and Y-axis offset. When the X-axis offset occurs, the sliding support cylinder 72... 01 drives the upper slide rail 7208 to slide along the X direction of the slider 7209. When the Y direction offset occurs, the sliding support cylinder 7201 drives the slider 7209 to slide along the bottom slide rail 7211 (i.e., the Y direction) through the upper slide rail 7208. Therefore, during installation, the cold mass bracket 3 is pre-offset installed according to the offset amount of cold contraction at low temperature. On the mass-produced thermostat, since the pre-offset amount in the three directions is based on theoretical calculation, a collimation measurement can be performed at low temperature to check and correct the pre-offset amount as necessary, thereby further improving the collimation at low temperature.

[0059] See Figure 17 The cold mass support unit also includes a cryogenic pipeline mounting bracket 31, which is fixedly connected to the top of the cold mass support 3 to support the cryogenic pipeline 8.

[0060] See Figure 18One end of the superconducting cavity 4 is fixedly connected to a first connecting plate 401, and the other end is fixedly connected to a second connecting plate 402. The cold mass support 3 has connecting parts 73, adapted to the first connecting plate 401 and the second connecting plate 402, fixedly connected to both ends. The connecting parts 73 include a first connecting platform 731, a second connecting platform 732, and a guide post 733. The first connecting platform 731 and the first connecting plate 401 are located on the same side of the superconducting cavity 4, and the second connecting platform 732 and the second connecting plate 402 are located on the same side of the superconducting cavity 4. The second connecting plate 402 is a rectangular plate, with a [missing information - likely a number] opening on each side of its top end near the second connecting platform 732. A waist hole 403 is provided, and a guide post 733 is fixed at the corresponding position of the second connecting platform 732. The waist hole 403 and the guide post 733 are shaped to fit each other and limit their movement. The top center of the end of the second connecting plate 402 near the second connecting platform 732 is fastened to the second connecting platform 732 by bolts 404. At low temperatures, because the center of the second connecting platform 732 is fixed, the two ends of the second connecting plate 402 shrink towards the center. The second connecting plate 402 is a U-shaped plate, with its large end face fixedly connected to the superconducting cavity 4, and both small end faces slidingly fixed to the first connecting platform 731 by a supporting sliding mechanism 405. (See reference...) Figure 19 , Figure 20 The supporting sliding mechanism 405 includes an upper sliding plate 4051, an upper fixed plate 4052, a lower sliding plate 4053, and a lower fixed plate 4054. The two small end faces of the second connecting plate 402 are each provided with mounting holes. These mounting holes are through holes with steps, the size of which is adapted to the dimensions of the upper sliding plate 4051, upper fixed plate 4052, lower sliding plate 4053, and lower fixed plate 4054. The lower fixed plate 4054 is located at the bottom of the lower sliding plate 4053 and is slidably connected to the lower sliding plate 4053 via multiple balls of the same diameter. The top of the lower fixed plate 4054 extends circumferentially... The sphere is provided with grooves at equal angles to fit the sphere. The grooves limit the sphere and prevent it from sliding out of the groove. It should be noted that the radius of the sphere is greater than the total amount of cold shrinkage of the superconducting cavity 4, the first connecting plate 401, and the second connecting plate 402. The lower sliding plate 4053 is snapped into the mounting hole, and the lower fixed plate 4054 is fixedly connected to the second connecting platform 732, thus realizing the sliding support between the first connecting platform 731 and the superconducting cavity 4. The upper fixed plate 4052 is fixedly connected to the mounting hole, and the upper sliding plate 4051 slides with the upper fixed plate 4052 through multiple spheres.

[0061] See Figure 2 , Figure 18Two superconducting cavities 4 are placed on the first cold mass support 3, one superconducting cavity 4 and one superconducting magnet 5 are placed on the second cold mass support 3, two superconducting cavities 4 are placed on the third cold mass support 3, and one superconducting cavity 4 and one superconducting magnet 5 are placed on the fourth cold mass support 3. Adjacent superconducting cavities 4 are connected sequentially by telescopic bellows. Both ends of the superconducting magnet 5 are connected to adjacent superconducting cavities 4 by telescopic bellows. The right end of the superconducting magnet 5 on the fourth cold mass support 3 is connected to the beam center 6 by a telescopic bellows. (See reference...) Figure 21 , Figure 22 A valve 11 is installed on the beam center 6. The cold mass needs to be assembled in the clean room. After assembly, it is transferred outside for the overall assembly of the thermostat. Before leaving the clean room, the beam vacuum needs to be sealed and protected. Therefore, a valve 11 is installed at both ends of the first cold mass support 3 and the fourth cold mass support 3. After the thermostat is installed, the valve 11 is fixedly connected to the inside of the vacuum chamber 10. A connection port 101 is fixedly connected to the vacuum chamber 10. A transmission rod 1010 is rotatably connected to the connection port 101, and rotational sealing is achieved through a sealing ring 1012. A baffle plate 1101 is movably connected inside valve 11. The baffle plate 1101 (valve core) is coaxial with the beam center 6 axis. Valve 11 is a commercially available part with an input end on its right side. Rotating the input end can drive the baffle plate 1101 to slide inside valve 11, thereby closing or opening the beam vacuum. One end of the transmission rod 1010 is formed with a hexagonal thread, and the other end is connected to the input end of valve 11 through a universal joint 1011. Eccentric transmission can be achieved without the universal joint 1011. A limit ring 1013 is fixedly connected to the transmission rod 1010 to prevent the transmission rod 1010 from being sucked in by the vacuum.

[0062] See Figure 18 The superconducting magnet 5 is movably fixed on the second cold mass support 3. One end of the superconducting magnet 5 is fixedly connected to the third connecting plate 501, and the other end is fixedly connected to the fourth connecting plate 502. The second cold mass support 3 is fixed with the third connecting platform 734 and the fourth connecting platform 735. The third connecting platform 734 and the third connecting plate 501 are located on the same side, and the fourth connecting platform 735 and the fourth connecting plate 502 are located on the same side. The fourth connecting platform 735 is fixedly connected to the fourth connecting plate 502 by two bolts. The third connecting plate 501 is slidably fixed to the third connecting platform 734 by the supporting sliding mechanism 405.

[0063] See Figure 23The cryogenic pipeline 8 provides refrigerant for the cold mass. The cryogenic pipeline 8 includes a main pipe 81 and branch pipes 82. The main pipe 81 includes a horizontal section and a vertical section. The vertical section of the main pipe 81 is equipped with a telescopic corrugated pipe to accommodate the amount of cold contraction in the vertical direction. The bottom of the horizontal section of the main pipe 81 is connected to multiple branch pipes 82. The top of the superconducting cavity 4 and the superconducting magnet 5 are both equipped with connecting pipes. Each branch pipe 82 is connected to a corresponding connecting pipe through a telescopic corrugated pipe. The corrugated pipe can compensate for the cryogenic cold contraction. The corrugated pipe is installed horizontally, which is beneficial for compensating for the large amount of cold contraction displacement in the beam direction. The fixed point of the cryogenic pipeline 8 is set in the middle position, and the main pipe 81 is placed symmetrically on both sides. Whether operating under negative or positive pressure, the force of the corrugated pipe will cancel each other out and will not cause impact on the main pipe 81, thereby maintaining the stability of the pipeline.

[0064] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. 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. Such 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 thermostat cold mass assembly, characterized in that, The system includes a cold mass support unit and multiple superconducting cavities and superconducting magnets connected in series on the cold mass support unit. The cryogenic thermostat includes a thermostat base plate and a cold mass support unit. The cold mass support unit is adjustablely mounted on the top of the thermostat base plate via a support assembly. Each end of the top of the cold mass support unit, connected to the superconducting cavities and superconducting magnets, has a matching connector. One end of each superconducting cavity is fixed to one connector, and the other end is slidably connected to another connector. At low temperatures, the superconducting cavity and superconducting magnets shrink and move from their sliding ends towards their fixed ends. The centerline of the connecting pipes between the multiple series-connected superconducting cavities and superconducting magnets forms the beam center. The cold mass support unit, superconducting cavities, and superconducting magnets are pre-offset from the beam center at room temperature. Installation: The cold mass support includes two symmetrically distributed cold mass supports. A connector is fixedly mounted on the top of the cold mass supports. One end of the superconducting cavity is fixedly connected to the cold mass support, and the other end is slidably engaged with the cold mass support. One end of the superconducting magnet is fixedly connected to the cold mass support, and the other end is slidably engaged with the cold mass support. Adjacent superconducting cavities and the superconducting magnet are connected to the superconducting cavity through telescopic corrugated pipes. A first connecting plate and a second connecting plate are fixedly connected to both ends of the superconducting cavity, respectively. The connector fixedly mounted on the top of the cold mass support is adapted to the first and second connecting plates. The connector includes a first connecting platform and a second connecting platform. The first connecting plate and the first connecting platform are slidably connected through a support sliding mechanism. The second connecting plate is fastened to the second connecting platform by bolts.

2. The thermostat cold mass assembly according to claim 1, characterized in that, The pre-offset of the cold mass support, the superconducting cavity, and the superconducting magnet are the differences in their dimensions at room temperature and at low temperature, respectively.

3. The thermostat cold mass assembly according to claim 1, characterized in that, The second connecting plate is a rectangular plate with waist holes on both sides of the top end facing the second connecting platform. A guide post is fixed on the top of the second connecting platform. The waist holes are adapted to the guide post. The bolt is located at the center of the line connecting the two waist holes.

4. The thermostat cold mass assembly according to claim 3, characterized in that, The supporting sliding mechanism includes a lower sliding plate and a lower fixed plate. The first connecting plate is a U-shaped plate with its large end face fixedly connected to the superconducting cavity. Both small end faces of the first connecting plate are formed with mounting holes adapted to the lower sliding plate. The lower sliding plate is fixedly connected in the mounting holes. The lower fixed plate is fixedly embedded in the top of the cold mass support. The lower sliding plate slides in cooperation with the lower fixed plate through multiple spheres. The radius of the spheres is greater than the sum of the cold shrinkage of the first connecting plate, the superconducting cavity, and the second connecting plate at low temperature.

5. A thermostat cold mass assembly according to claim 4, characterized in that, The superconducting magnet has a third connecting plate and a fourth connecting plate fixedly connected to its two ends, respectively. The top of the cold mass support has a third connecting platform and a fourth connecting platform that are adapted to the third connecting plate and the fourth connecting plate. The fourth connecting plate is fixedly connected to the fourth connecting platform, and the third connecting plate is slidably connected to the third connecting platform through a support sliding mechanism.

6. The thermostat cold mass assembly according to claim 1, characterized in that, It also includes cryogenic pipelines, and the cold mass support unit further includes a cryogenic pipeline mounting bracket, which is fixedly mounted on the top of the cold mass support and provides installation support for the cryogenic pipelines.

7. A thermostat cold mass assembly according to claim 6, characterized in that, The cryogenic pipeline includes a main pipe and branch pipes. The main pipe includes a vertical section and a horizontal section. A telescopic corrugated pipe is provided on the vertical section of the main pipe. Multiple branch pipes are connected to the bottom of the horizontal section of the main pipe. A connecting pipe is provided at the top of the superconducting cavity and the superconducting magnet. The branch pipes are respectively connected to the connecting pipes through telescopic corrugated pipes.

8. A thermostat cold mass assembly according to claim 7, characterized in that, The telescopic corrugated pipe connecting the branch pipe and the connecting pipe is installed horizontally.

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