Shielding cavity device for liquid helium low-temperature system

Abstract

The invention discloses a shielding cavity device for a liquid helium low-temperature system, which comprises a first shielding cylinder, a second shielding cylinder and a hoisting fixing device, and improves the relative position stability of the second shielding cylinder in the first shielding cylinder and the relative position stability of the first shielding cylinder in an outer vacuum device in a hoisting connection mode. The problem of position deviation caused by thermal expansion and cold contraction of the low-temperature device in the process from normal temperature to low temperature is solved; the first shielding cylinder and the second shielding cylinder are both formed by processing the annealed oxygen-free copper with the purity of 99.995% or above, and the heat radiation coefficient lt can be obtained under the condition that only the oxygen-free copper raw material is utilized; the radiation shielding effect is 0.02, and the temperature gradient 1t of the whole second shielding cylinder can be achieved under the condition that the volume exceeds 10 liters; the low-temperature system has the advantages that the overall heat load of the low-temperature system is reduced, the heat shielding effect is improved, the temperature uniformity in the first shielding cylinder and the second shielding cylinder is improved, and meanwhile the cost is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of quantum computing and low-temperature superconducting technology, and specifically relates to a shielding cavity device for a liquid helium cryogenic system, which is suitable for improving the temperature uniformity of the shielding cavity and avoiding the relative position distortion of various parts of the shielding cavity and the shielding cavity and an external vacuum cavity caused by thermal expansion and contraction. Background Art

[0002] Quantum computing and low-temperature superconductivity have a wide range of forward-looking applications, covering national defense quantum communication security, new superconducting material research and development, superconducting medical imaging, high-energy physics and other aspects. Whether it is quantum computing or low-temperature superconductivity, the most basic requirement is to provide a stable liquid helium low-temperature environment, so a very critical technology is heat shielding.

[0003] Currently, the most mainstream way to provide a liquid helium low-temperature environment is to use a liquid helium refrigerator to provide cooling capacity to cool the required system. However, the cooling power of the refrigerator is usually only about 1W at a low temperature of liquid helium 4K, and it decreases as the required temperature decreases. Therefore, this greatly limits the lowest temperature that the system can reach and the maximum load of the system. There are two keys to solving this problem. One is to increase the research and development of refrigerators with greater cooling power, and the other is to optimize the system load, including reducing the system load caused by thermal radiation and heat conduction by increasing the thermal shielding effect.

[0004] The core of thermal shielding is to increase thermal impedance. The current traditional methods include multi-layer tin foil winding, low thermal conductivity absorption materials such as thermal insulation cotton winding, vacuum isolation and other methods. However, these single technologies can only reduce heat conduction or heat radiation, and it is difficult to completely and effectively perform thermal shielding. A more advanced method is to use a gold-plated metal shielding layer to form a shield for thermal radiation, supplemented by low thermal conductivity materials to connect and support each shielding layer. This method has also been effectively applied in the fields of quantum computing and low-temperature superconductivity. However, there are problems: 1. The cost of gold plating the shielding layer is difficult to control; 2. The relative position between each shielding layer and between the shielding layer and the low-temperature component is prone to distortion during thermal expansion and contraction; 3. The temperature between each shielding layer is uneven. Summary of the invention

[0005] The object of the present invention is to provide a shielding chamber device for a liquid helium cryogenic system in view of the above-mentioned problems existing in the prior art.

[0006] The above-mentioned purpose of the present invention is achieved by the following technical means:

[0007] A shielding chamber device for a liquid helium cryogenic system comprises a first shielding tube and a second shielding tube, and further comprises a first upper fixed steel ring, a first lower fixed steel ring, a second upper fixed steel ring, a second lower fixed steel ring, and a plurality of steel wires, wherein the second shielding tube is arranged in the first shielding tube, the second shielding tube and the first shielding tube share a common central axis, the first upper fixed steel ring and the first lower fixed steel ring are respectively fixedly connected to the top and the bottom of the tube wall of the first shielding tube by bolts, the second upper fixed steel ring and the second lower fixed steel ring are respectively fixedly connected to the top and the bottom of the tube wall of the second shielding tube by bolts, the inner side walls of the first upper fixed steel ring and the first lower fixed steel ring are respectively uniformly provided with the same number of inward convex fixing groups, each inward convex fixing group comprises a pair of inward convex fixing blocks The same number of convex connecting blocks are evenly arranged on the outer side walls of the second upper fixing steel ring and the second lower fixing steel ring respectively, the number of the convex connecting blocks of the first upper fixing steel ring is the same as the number of the convex fixing groups of the second lower fixing steel ring, each convex connecting block of the second lower fixing steel ring is fixedly connected to the two convex fixing blocks in one of the first convex fixing groups of the first upper fixing steel ring by steel wire, each convex connecting block of the second upper fixing steel ring is fixedly connected to the two convex fixing blocks in one of the first convex connections of the first lower fixing steel ring by steel wire, and the vertical projections of each convex connecting block of the second upper fixing steel ring and the second lower fixing steel ring are located on the symmetry axis of the vertical projections of the two convex fixing blocks connected to the corresponding convex connecting block.

[0008] The vertical projections of all the outer convex connection blocks of the second upper fixing steel ring and the second lower fixing steel ring are evenly distributed on the vertical projection circle of the second lower fixing steel ring.

[0009] One end of each steel wire is provided with an external thread, and the other end is provided with a nut. The external convex connecting block is provided with an oblique threaded hole, and the internal convex fixing block is provided with a fixing hole. The threaded end of the steel wire passes through the fixing hole and is then screwed into the oblique threaded hole, thereby fixing the corresponding external convex connecting block and the internal convex fixing block, and the bottom surface of the nut is tightly fitted with the surface of the internal convex fixing block.

[0010] As described above, the top and bottom of the first shielding cylinder are respectively provided with a first cover plate and a first bottom plate, the first cover plate is fixedly connected to the first upper fixed steel ring, the first bottom plate is fixedly connected to the first lower fixed steel ring, a first opening is provided at the center of the first cover plate, the first large sealing cover is adapted to the shape and size of the first opening, a first light-through hole is provided at the center of the first large sealing cover, and the first small sealing cover is adapted to the shape and size of the first light-through hole;

[0011] As mentioned above, the top and bottom of the second shielding tube are respectively provided with a second cover plate and a second bottom plate, the second cover plate is fixedly connected to the second upper fixed steel ring, the second bottom plate is fixedly connected to the second lower fixed steel ring, a second opening is opened in the center of the second cover plate, the second large sealing cover is adapted to the shape and size of the second opening, a second light-through hole is opened in the center of the second large sealing cover, and the second small sealing cover is adapted to the shape and size of the second light-through hole.

[0012] As described above, the side walls of the first shielding tube and the second shielding tube are respectively provided with a plurality of third light-through holes and a fourth light-through holes corresponding to the positions thereof in the circumferential direction; all surfaces of the first shielding tube and the second shielding tube are mirror-polished; the first shielding tube is fixedly connected to the first cover plate and the first base plate by silver-plated bolts, and the second shielding tube is fixedly connected to the second cover plate and the second base plate by silver-plated bolts; grease is applied to the first shielding tube and the first cover plate and the first base plate, and grease is applied to the contact surfaces between the second shielding tube and the second cover plate and the second base plate.

[0013] It also includes an external vacuum device, on which the upper inner wall and the lower inner wall of the external vacuum device are respectively uniformly provided with the same number of inward convex fixing groups along the circumferential direction, each inward convex fixing group includes a pair of inward convex fixing blocks, and the outer side walls of the first upper fixing steel ring and the first lower fixing steel ring are respectively uniformly provided with the same number of outward convex connecting blocks, the number of inward convex fixing groups of the external vacuum device is the same as the number of all outward convex connecting blocks of the first upper fixing steel ring and the first lower fixing steel ring, and the vertical height difference between the plane where the inward convex fixing blocks at the upper inner wall are located and the plane where the first lower fixing steel ring is located is the same as the vertical height difference between the plane where the inward convex fixing blocks at the lower inner wall are located and the plane where the first upper fixing steel ring is located. The same; each convex connecting block of the first lower fixed steel ring is fixedly connected to two convex fixing blocks in one of the convex fixing groups on the upper inner wall of the external vacuum device by steel wires, each convex connecting block of the first upper fixed steel ring is fixedly connected to two convex fixing blocks in one of the convex connections on the lower inner wall of the external vacuum device by steel wires, the vertical projections of each convex connecting block of the first upper fixed steel ring and the first lower fixed steel ring are located on the symmetry axis of the vertical projections of the two convex fixing blocks connected to the corresponding convex connecting blocks, and the vertical projections of all convex connecting blocks of the first upper fixed steel ring and the first lower fixed steel ring are evenly distributed on the vertical projection circle of the first lower fixed steel ring.

[0014] As mentioned above, the vertical height difference between the plane where the inwardly convex fixing block on the upper inner wall is located and the plane where the first lower fixed steel ring is located is the same as the vertical height difference between the plane where the inwardly convex fixing block on the lower inner wall is located and the plane where the first upper fixed steel ring is located.

[0015] It also includes a liquid helium refrigerator. Cold head insertion holes are provided on the side walls of the external vacuum device, the first shielding tube and the second shielding tube. The cold head of the liquid helium refrigerator includes a primary cold head and a secondary cold head. The secondary cold head is arranged inside the primary cold head. The length of the secondary cold head is greater than that of the primary cold head. Both the primary cold head and the secondary cold head are provided with outward-turned fixing rings. The primary cold head passes through the cold head insertion holes of the external vacuum device and the first shielding tube in turn, and is fixedly connected to the outer side wall of the first shielding tube by bolts through the outward-turned fixing ring of the primary cold head. The secondary cold head passes through the cold head insertion hole of the second shielding tube, and is fixedly connected to the outer side wall of the second shielding tube by bolts through the outward-turned fixing ring of the secondary cold head.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention improves the relative position stability of the second shielding tube in the first shielding tube and the relative position stability of the first shielding tube in the external vacuum device by means of a hanging connection, thereby solving the problem of positional displacement caused by thermal expansion and contraction of the cryogenic device from normal temperature to low temperature.

[0018] (2) The first shielding tube and the second shielding tube of the present invention are both made of oxygen-free copper with a purity of more than 99.995% and annealed, and can achieve a radiation shielding effect with a thermal radiation coefficient of less than 0.02 using only oxygen-free copper raw materials. This is a method for obtaining a low thermal radiation coefficient different from surface gold plating. The overall temperature gradient of the second shielding tube can be achieved at a volume of more than 10 liters. It reduces the overall heat load of the cryogenic system, improves the thermal shielding effect of the traditional thermal radiation shielding layer design, improves the temperature uniformity of the cavity, and reduces costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic structural diagram of a 40K shielding device, a 4K shielding device, and a hanging and fixing device of the present invention;

[0020] Figure 2 It is a structural schematic diagram of the hanging and fixing device of the present invention;

[0021] Figure 3 It is a schematic structural diagram of the external vacuum device of the present invention and the cold head of the liquid helium refrigerator connected with the 40K shielding device and the 4K shielding device;

[0022] Reference numerals and corresponding component names:

[0023] 101-first cover plate; 102-first shielding tube; 103-first bottom plate; 104-first large sealing cover; 105-first small sealing cover; 106-third light-through hole; 201-second cover plate; 202-second shielding tube; 203-second bottom plate; 204-second large sealing cover; 205-second small sealing cover; 206-fourth light-through hole; 301-first upper fixed steel ring; 302-first lower fixed steel ring; 303-second upper fixed steel ring; 304-second lower fixed steel ring; 305-steel wire; 306-external convex connecting block; 307-inner convex fixing block; 401-liquid helium refrigerator; 402-secondary cold head; 403-external vacuum device; 405-low-temperature ion trap; 406-primary cold head. DETAILED DESCRIPTION

[0024] In order to facilitate those skilled in the art to understand and implement the present invention, the present invention is further described in detail below in conjunction with embodiments. The embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0025] Embodiment 1:

[0026] A shielding chamber device for a liquid helium cryogenic system, comprising a 40K shielding device, a 4K shielding device, and a hanging and fixing device, wherein the 40K shielding device comprises a first shielding cylinder 102 (i.e., a 40K shielding cylinder), the 4K shielding device comprises a second shielding cylinder 202 (i.e., a 4K shielding cylinder), the second shielding cylinder 202 is arranged in the first shielding cylinder 102, the second shielding cylinder 202 and the first shielding cylinder 102 share a central axis, the hanging and fixing device comprises a first upper fixing steel ring 301, a first lower fixing steel ring 302, a second upper fixing steel ring 303, a second lower fixing steel ring 304, and and a plurality of steel wires 305, a first upper fixing steel ring 301 and a first lower fixing steel ring 302 are respectively fixedly connected to the top and bottom of the cylinder wall of the first shielding cylinder 102 by bolts, a second upper fixing steel ring 303 and a second lower fixing steel ring 304 are respectively fixedly connected to the top and bottom of the cylinder wall of the second shielding cylinder 202 by bolts, and the inner side walls of the first upper fixing steel ring 301 and the first lower fixing steel ring 302 are respectively uniformly provided with the same number of inward convex fixing groups, each inward convex fixing group includes a pair of inward convex fixing blocks 307, and the second upper fixing steel ring 303 and the second lower fixing steel ring 304 are respectively fixedly connected to the top and bottom of the cylinder wall of the second shielding cylinder 202 by bolts. The outer side walls of the first upper fixing steel ring 304 are evenly provided with the same number of external convex connection blocks 306, the number of the external convex connection blocks 306 of the first upper fixing steel ring 301 is the same as the number of the internal convex fixing groups of the second lower fixing steel ring 304, each external convex connection block 306 of the second lower fixing steel ring 304 is fixedly connected to two internal convex fixing blocks 307 in one of the first internal convex fixing groups of the first upper fixing steel ring 301 by a steel wire 305, and each external convex connection block 306 of the second upper fixing steel ring 303 is fixedly connected to two internal convex fixing blocks 307 in one of the first internal convex connections of the first lower fixing steel ring 302 by a steel wire 305. The block 307 is fixedly connected by the steel wire 305. When the second shielding cylinder 202 tends to move upward, the first upper fixed steel ring 301 can generate an overall downward thrust on the second shielding cylinder 202, and the first lower fixed steel ring 302 has an overall downward pulling force on the second shielding cylinder 202; when the second shielding cylinder 202 tends to move upward, the first upper fixed steel ring 301 can generate an overall upward pulling force on the second shielding cylinder 202, and the first lower fixed steel ring 302 has an overall upward thrust on the second shielding cylinder 202, which can ensure that the vertical position of the second shielding cylinder 202 is fixed;

[0027] The vertical projection of each outwardly convex connecting block 306 of the second upper fixed steel ring 303 and the second lower fixed steel ring 304 is located on the symmetry axis of the vertical projection of the two inwardly convex fixing blocks 307 connected to the corresponding outwardly convex connecting block 306, so that the two steel wires 305 connected to each outwardly convex connecting block 306 can have force components in opposite directions in the tangential direction of the corresponding outwardly convex connecting block 306, thereby avoiding the overall rotation of the second shielding tube 202, ensuring the horizontal position of the second shielding device is fixed, improving the relative position stability of the second shielding tube 202 in the first shielding tube 102, and solving the problem of position deviation caused by thermal expansion and contraction of the low-temperature device from normal temperature to low temperature.

[0028] The vertical projections of all the protruding connecting blocks 306 of the second upper fixed steel ring 303 and the second lower fixed steel ring 304 are evenly distributed on the vertical projection circle of the second upper fixed steel ring 303 (or the second lower fixed steel ring 304), so that the steel wires 305 connected to the second upper fixed steel ring 303 and the steel wires 305 connected to the second lower fixed steel ring 304 can be staggered without interlacing, and the uniform distribution can better maintain the balance of the second shielding tube 202.

[0029] As an implementation method, one end of each steel wire 305 is provided with an external thread (i.e., a threaded end), and the other end (i.e., a non-threaded end) is provided with a nut, the external convex connecting block 306 (or the internal convex fixing block 307) is provided with an oblique threaded hole, and the internal convex fixing block 307 (or the external convex connecting block 306) is provided with a fixing hole, the threaded end of the steel wire 305 passes through the fixing hole and is then screwed into the oblique threaded hole, thereby fixing the corresponding external convex connecting block 306 and the internal convex fixing block 307, and the bottom surface of the nut is at a set angle (non-vertical) to the steel wire 305, so that after the steel wire 305 is connected, the bottom surface of the nut at the non-threaded end is tightly fitted with the surface of the internal convex fixing block 307 (or the external convex connecting block 306), thereby making the connection more secure.

[0030] The top and bottom of the first shielding tube 102 are respectively provided with a first cover plate 101 and a first bottom plate 103. The first cover plate 101 is fixedly connected to the first upper fixed steel ring 301, and the first bottom plate 103 is fixedly connected to the first lower fixed steel ring 302. A first opening is opened in the center of the first cover plate 101, and the first large sealing cover 104 is adapted to the shape and size of the first opening. A first light-through hole is opened in the center of the first large sealing cover 104, and the first small sealing cover 105 is adapted to the shape and size of the first light-through hole.

[0031] The second shielding tube 202 is provided with a second cover plate 201 and a second bottom plate 203 at the top and bottom respectively. The second cover plate 201 is fixedly connected to the second upper fixed steel ring 303, and the second bottom plate 203 is fixedly connected to the second lower fixed steel ring 304. A second opening is provided at the center of the second cover plate 201. The second large sealing cover 204 is adapted to the shape and size of the second opening. A second light-through hole is provided at the center of the second large sealing cover 204, and the second small sealing cover 205 is adapted to the shape and size of the second light-through hole.

[0032] The first opening and the second opening are used to place the low-temperature ion trap 405 into the second shielding tube 202, and the first light through hole and the second light through hole are used for light transmission and vacuuming.

[0033] As an implementation method, Figure 1 As shown, the side wall of the first opening is stepped, and an assembly threaded hole is provided on the horizontal step surface of the first opening. The first large sealing cover is also provided with a fixing threaded hole of corresponding position. The first large sealing cover is fixedly connected to the first cover plate through the assembly threaded hole and the fixing threaded hole; the second large sealing cover and the second opening can also be fixedly connected in the above manner.

[0034] The side walls of the first shielding cylinder 102 and the second shielding cylinder 202 are respectively provided with a plurality of corresponding third light-through holes 106 and fourth light-through holes 206 along the circumferential direction;

[0035] All surfaces of the first shielding tube 102 and the second shielding tube 202 are mirror-polished, and the mirror finish Ra<0.1 is used to control the radiation coefficient of the surface of the first shielding tube 102 and the second shielding tube 202 to within 0.02.

[0036] The first shielding tube 102 is fixedly connected to the first cover plate 101 and the first bottom plate 103 by silver-plated bolts, and the second shielding tube 202 is fixedly connected to the second cover plate 201 and the second bottom plate 203 by silver-plated bolts, with a torque of >5Nm, to reduce the thermal impedance of the contact surface.

[0037] Grease is applied between the first shielding cylinder 102 and the first cover plate 101 and the first bottom plate 103 , and grease is applied on the contact surfaces between the second shielding cylinder 202 and the second cover plate 201 and the second bottom plate 203 to increase the effective contact surface.

[0038] In this embodiment, the outer diameter of the first shielding tube 102 is 450 mm, the height is 350 mm, the maximum diameter of the first opening is 150 mm, and the diameter of the first light-through hole is 15 mm; the outer diameter of the second shielding tube 202 is 300 mm, the height is 200 mm, the maximum diameter of the second opening is 150 mm, and the diameter of the second light-through hole is 15 mm; the diameter of the steel wire 305 is 2 mm, the length of the threaded end of the steel wire 305 is 2 cm, and the maximum diameter of the nut is 4 mm.

[0039] The first shielding tube 102 is used to isolate the thermal radiation of the external room temperature cavity, and the second shielding tube 202 is used to isolate the thermal radiation of the first shielding tube 102. The first shielding tube 102 and the second shielding tube 202 are both made of oxygen-free copper with a purity of more than 99.995% and annealed. The radiation shielding effect with a thermal radiation coefficient of <0.02 can be obtained by using only oxygen-free copper raw materials. It is a low thermal radiation coefficient acquisition method different from the surface gold plating treatment. The overall temperature gradient of the second shielding tube 202 can be <1 Kelvin in a volume of more than 10 liters, which reduces the overall heat load of the low-temperature system and improves the thermal shielding effect of the traditional thermal radiation shielding layer design.

[0040] It also includes an external vacuum device 403, and the external vacuum device 403 is also connected to the first shielding cylinder 102 by hanging in the same way, specifically: the same number of inward convex fixing groups are evenly arranged on the upper inner wall and the lower inner wall of the external vacuum device 403 along the circumferential direction, each inward convex fixing group includes a pair of inward convex fixing blocks 307, and the same number of outward convex connecting blocks 306 are evenly arranged on the outer side walls of the first upper fixing steel ring 301 and the first lower fixing steel ring 302, the number of inward convex fixing groups of the external vacuum device 403 is the same as the number of all outward convex connecting blocks 306 of the first upper fixing steel ring 301 and the first lower fixing steel ring 302, and the vertical height difference between the plane where the inward convex fixing blocks 307 at the upper inner wall are located and the plane where the first lower fixing steel ring 302 are located is the same as the vertical height difference between the plane where the inward convex fixing blocks 307 at the lower inner wall are located and the plane where the first upper fixing steel ring 301 are located;

[0041] Each convex connecting block 306 of the first lower fixed steel ring 302 is fixedly connected to two convex fixing blocks 307 in one of the convex fixing groups on the upper inner wall of the external vacuum device 403 by a steel wire 305, and each convex connecting block 306 of the first upper fixed steel ring 301 is fixedly connected to two convex fixing blocks 307 in one of the convex connections on the lower inner wall of the external vacuum device 403 by a steel wire 305, and the vertical projections of each convex connecting block 306 of the first upper fixed steel ring 301 and the first lower fixed steel ring 302 are located on the symmetry axis of the vertical projections of the two convex fixing blocks 307 connected to the corresponding convex connecting block 306, and the vertical projections of all the convex connecting blocks 306 of the first upper fixed steel ring 301 and the first lower fixed steel ring 302 are evenly distributed on the vertical projection circle of the first lower fixed steel ring 302 (first upper fixed steel ring 301).

[0042] The outer vacuum device 403 and the first shielding tube 102 are also connected by hanging in the same way, so as to fix the position of the first shielding tube 102 in the outer vacuum device 403, thereby improving the relative position stability of the first shielding tube 102 in the outer vacuum device 403 and solving the position deviation problem caused by thermal expansion and contraction of the low-temperature device from normal temperature to low temperature.

[0043] It also includes a liquid helium refrigerator 401, and cold head insertion holes are provided on the side walls of the external vacuum device 403, the first shielding tube 102, and the second shielding tube 202. The cold head of the liquid helium refrigerator 401 includes a primary cold head 406 (i.e., a 40K cold head) and a secondary cold head 402 (i.e., a 4K cold head). The secondary cold head 402 is arranged inside the primary cold head 406, and the length of the secondary cold head 402 is greater than the length of the primary cold head 406. Both the primary cold head 406 and the secondary cold head 402 are provided with outward-turned fixing rings. The primary cold head 406 passes through the cold head insertion holes of the external vacuum device 403 and the first shielding tube 102 in turn, and is fixedly connected to the outer side wall of the first shielding tube 102 by bolts through the outward-turned fixing ring of the primary cold head 406. The secondary cold head 402 passes through the cold head insertion hole of the second shielding tube 202, and is fixedly connected to the outer side wall of the second shielding tube 202 by bolts through the outward-turned fixing ring of the secondary cold head 402.

[0044] The 40K cold head and the 4K cold head are used for refrigeration conduction of the refrigerator. The 40K cold head provides 20W refrigeration power, and the 4K cold head provides 1.5W refrigeration power. The 40K cold head is connected to the first shielding tube 102, so that the heat of the first shielding tube 102 is taken away to reach the equilibrium temperature. The mirror surface of the first shielding tube 102 can reflect most of the external radiation, so that the load caused by the heat radiation conduction is reduced to 10W. At the same time, in the steel wire 305 hanging connection mode, the load caused by the heat conduction of the steel wire 305 can be reduced to 1W. Therefore, the load connected to the 40K cold head is less than 20W, which can make the first shielding tube 102 and the interior achieve a stable temperature of 40K.

[0045] The 4K cold head is connected to the second shielding tube 202. The mirror surface of the second shielding tube 202 can reflect most of the external radiation, so that the load caused by thermal radiation conduction is reduced to 0.1W. At the same time, in the hanging connection mode of the steel wire 305, the load caused by the heat conduction of the steel wire 305 can be reduced to below 0.1W. Therefore, the load connected to the 4K cold head is less than 0.2W, which can make the second shielding tube 202, the interior of the second shielding tube 202, and the low-temperature ion trap 405 as a whole achieve a stable temperature of 4K.

[0046] The present invention is not only applicable to quantum computing ion trap systems, but also to various types of systems and equipment such as superconducting quantum computing and low-temperature atom preparation systems that require providing three-dimensional stable thermal shielding for low-temperature environments.

[0047] It should be noted that the embodiments described in the present invention are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the described embodiments or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims.

Claims

1. A shielding chamber device for a liquid helium cryogenic system, comprising a first shielding cylinder (102) and a second shielding cylinder (202), characterized in that: The invention also comprises a first upper fixing steel ring (301), a first lower fixing steel ring (302), a second upper fixing steel ring (303), a second lower fixing steel ring (304), and a plurality of steel wires (305); the second shielding cylinder (202) is arranged in the first shielding cylinder (102); the second shielding cylinder (202) and the first shielding cylinder (102) share a common central axis; the first upper fixing steel ring (301) and the first lower fixing steel ring (302) are respectively fixed to the first shielding cylinder (102) by bolts; The top and bottom of the cylinder wall are fixedly connected, the second upper fixing steel ring (303) and the second lower fixing steel ring (304) are respectively fixedly connected to the top and bottom of the cylinder wall of the second shielding cylinder (202) by bolts, and the same number of inner convex fixing groups are evenly arranged on the inner side walls of the first upper fixing steel ring (301) and the first lower fixing steel ring (302), each inner convex fixing group includes a pair of inner convex fixing blocks (307), the second upper fixing steel ring (303) and the second lower fixing steel ring (3 04) are evenly provided with the same number of external convex connection blocks (306), the number of the external convex connection blocks (306) of the first upper fixing steel ring (301) is the same as the number of the internal convex fixing groups of the second lower fixing steel ring (304), each external convex connection block (306) of the second lower fixing steel ring (304) is fixedly connected to two internal convex fixing blocks (307) in one of the first internal convex fixing groups of the first upper fixing steel ring (301) by a steel wire (305), and the first Each external convex connecting block (306) of the second upper fixing steel ring (303) is fixedly connected to two internal convex fixing blocks (307) in one of the first internal convex connections of the first lower fixing steel ring (302) by means of steel wires (305), and the vertical projections of each external convex connecting block (306) of the second upper fixing steel ring (303) and the second lower fixing steel ring (304) are located on the symmetry axis of the vertical projections of the two internal convex fixing blocks (307) connected to the corresponding external convex connecting block (306).

2. A shielding chamber device for a liquid helium cryogenic system according to claim 1, characterized in that: The vertical projections of all the outer convex connection blocks (306) of the second upper fixing steel ring (303) and the second lower fixing steel ring (304) are evenly distributed on the vertical projection circle of the second lower fixing steel ring (304).

3. A shielding chamber device for a liquid helium cryogenic system according to claim 2, characterized in that: One end of each steel wire (305) is provided with an external thread, and the other end is provided with a nut. The external convex connecting block (306) is provided with an oblique threaded hole, and the internal convex fixing block (307) is provided with a fixing hole. The threaded end of the steel wire (305) passes through the fixing hole and is then screwed into the oblique threaded hole, thereby fixing the corresponding external convex connecting block (306) and the internal convex fixing block (307), and the bottom surface of the nut is tightly fitted with the surface of the internal convex fixing block (307).

4. A shielding chamber device for a liquid helium cryogenic system according to claim 3, characterized in that: The top and bottom of the first shielding cylinder (102) are respectively provided with a first cover plate (101) and a first bottom plate (103); the first cover plate (101) is fixedly connected to the first upper fixed steel ring (301); the first bottom plate (103) is fixedly connected to the first lower fixed steel ring (302); a first opening is provided at the center of the first cover plate (101); the first large sealing cover (104) is adapted to the shape and size of the first opening; a first light-through hole is provided at the center of the first large sealing cover (104); and the first small sealing cover (105) is adapted to the shape and size of the first light-through hole; The top and bottom of the second shielding tube (202) are respectively provided with a second cover plate (201) and a second bottom plate (203); the second cover plate (201) is fixedly connected to the second upper fixed steel ring (303); the second bottom plate (203) is fixedly connected to the second lower fixed steel ring (304); a second opening is provided at the center of the second cover plate (201); the second large sealing cover (204) is adapted to the shape and size of the second opening; a second light-through hole is provided at the center of the second large sealing cover (204); and the second small sealing cover (205) is adapted to the shape and size of the second light-through hole.

5. A shielding chamber device for a liquid helium cryogenic system according to claim 4, characterized in that: The side walls of the first shielding cylinder (102) and the second shielding cylinder (202) are respectively provided with a plurality of third light-through holes (106) and a fourth light-through hole (206) at corresponding positions along the circumferential direction; all surfaces of the first shielding cylinder (102) and the second shielding cylinder (202) are mirror-polished; the first shielding cylinder (102) is fixedly connected to the first cover plate (101) and the first bottom plate (103) by silver-plated bolts, and the second shielding cylinder (202) is fixedly connected to the second cover plate (201) and the second bottom plate (203) by silver-plated bolts; grease is applied between the first shielding cylinder (102) and the first cover plate (101) and the first bottom plate (103), and grease is applied to the contact surfaces between the second shielding cylinder (202) and the second cover plate (201) and the second bottom plate (203).

6. The shielding chamber device for a liquid helium cryogenic system according to claim 2, characterized in that: The outer vacuum device (403) further comprises an outer vacuum device (403), wherein the upper inner wall and the lower inner wall of the outer vacuum device (403) are respectively uniformly provided with the same number of inward convex fixing groups along the circumferential direction, each inward convex fixing group comprises a pair of inward convex fixing blocks (307), and the outer side walls of the first upper fixing steel ring (301) and the first lower fixing steel ring (302) are respectively uniformly provided with the same number of outward convex connecting blocks (306), the number of inward convex fixing groups of the outer vacuum device (403) is the same as the number of all outward convex connecting blocks (306) of the first upper fixing steel ring (301) and the first lower fixing steel ring (302), the vertical height difference between the plane where the inward convex fixing blocks (307) on the upper inner wall are located and the plane where the first lower fixing steel ring (302) is located is the same as the vertical height difference between the plane where the inward convex fixing blocks (307) on the lower inner wall are located and the plane where the first upper fixing steel ring (301) is located; the first lower fixing steel ring (302) ) is fixedly connected to two inwardly convex fixing blocks (307) in one inwardly convex fixing group of the upper inner wall of the external vacuum device (403) by means of a steel wire (305); each outwardly convex connecting block (306) of the first upper fixing steel ring (301) is fixedly connected to two inwardly convex fixing blocks (307) in one inwardly convex connection of the lower inner wall of the external vacuum device (403) by means of a steel wire (305); the vertical projections of each outwardly convex connecting block (306) of the first upper fixing steel ring (301) and the first lower fixing steel ring (302) are located on the symmetry axis of the vertical projections of the two inwardly convex fixing blocks (307) connected to the corresponding outwardly convex connecting block (306); the vertical projections of all the outwardly convex connecting blocks (306) of the first upper fixing steel ring (301) and the first lower fixing steel ring (302) are evenly distributed on the vertical projection circle of the first lower fixing steel ring (302).

7. A shielding chamber device for a liquid helium cryogenic system according to claim 6, characterized in that: The vertical height difference between the plane where the inwardly convex fixing block (307) on the upper inner wall is located and the plane where the first lower fixing steel ring (302) is located is the same as the vertical height difference between the plane where the inwardly convex fixing block (307) on the lower inner wall is located and the plane where the first upper fixing steel ring (301) is located.

8. A shielding chamber device for a liquid helium cryogenic system according to claim 7, characterized in that: The invention also comprises a liquid helium refrigerator (401), and the side walls of the outer vacuum device (403), the first shielding tube (102), and the second shielding tube (202) are all provided with cold head insertion holes. The cold head of the liquid helium refrigerator (401) comprises a primary cold head (406) and a secondary cold head (402). The secondary cold head (402) is arranged inside the primary cold head (406). The length of the secondary cold head (402) is greater than the length of the primary cold head (406). The primary cold head (406) and the secondary cold head (402) are connected to each other. ) are provided with an outward-turned fixing ring, the first-level cold head (406) passes through the cold head insertion hole of the external vacuum device (403) and the first shielding tube (102) in turn, and is fixedly connected to the outer wall of the first shielding tube (102) by bolts through the outward-turned fixing ring of the first-level cold head (406), and the second-level cold head (402) passes through the cold head insertion hole of the second shielding tube (202), and is fixedly connected to the outer wall of the second shielding tube (202) by bolts through the outward-turned fixing ring of the second-level cold head (402).

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