A continuous flow differential pressure reduction ultra-high vacuum low temperature device

Abstract

The invention relates to the technical field of ultra-high vacuum and ultra-low temperature experiments, and discloses a continuous flow differential decompression ultra-high vacuum and low temperature device, comprising a low temperature thermostat and a refrigeration module, and the structure is as follows: the low temperature thermostat comprises a low temperature cavity, a conduit and a tube shell, wherein: the low temperature cavity comprises a protective cover, a cold screen with a cylindrical structure is fixed in the protective cover, a 2K cell and a 1.3K cell are fixed in the cold screen, the 2K cell is located above the 1.3K cell, and the two are separated by a partition; a vaporizer is fixed at the bottom of the cold screen, a sample holder for holding samples is fixed below the vaporizer, and the vaporizer is a matrix-type porous structure; the refrigeration module provided by the invention is independently designed from the low temperature thermostat, and while providing low temperature helium to the low temperature thermostat, the vibration generated when the refrigerator is working is avoided from being transmitted to the low temperature thermostat, so as to greatly reduce the vibration of the low temperature thermostat and has the characteristics of significant cooling effect, wide temperature change range, compact structure and strong matching.

Description

Technical Field

[0001] The present invention relates to the technical field of ultra-high vacuum and ultra-low temperature experiments, and more specifically, to a continuous flow differential decompression ultra-high vacuum and low temperature device. Background Art

[0002] The research on quantum materials began around the late 1970s. It is a new type of material with unique electronic structure and physical properties that can help scientists better understand and manipulate quantum phenomena. At present, the research on quantum materials has become a very important scientific frontier. It is a bridge and foundation for the cross-integration of multiple disciplines such as condensed matter physics and materials science, and is widely used in quantum computing, quantum communications, biomedicine, new energy and other industries.

[0003] With the continuous advancement of quantum material preparation technology and characterization methods, X-ray, STM, SEM, ARPES and other technologies have become powerful tools for quantum material research. These research methods require that quantum materials be placed in extreme environments of ultra-low temperature, ultra-high vacuum, and ultra-low vibration.

[0004] Ultra-low temperature, ultra-high vacuum, and ultra-low vibration devices are generally divided into two categories. One category uses refrigerant (liquid helium) as a cold source. This type of device has a low vibration level, but requires continuous consumption and replenishment of liquid helium, which is not conducive to the continuity of the experiment, increases R&D investment, and cannot meet long-term R&D needs; the other category is a low-temperature system that uses a refrigerator as a cold source and does not consume liquid helium. Taking CN106524554A as an example, the refrigerator and the sample of this device are mechanically fixed to form an integrated structure. The vibration generated when the refrigerator is working will be transmitted to the sample; and it is a single-shot design, and the refrigerant cannot be recycled repeatedly; the component for obtaining the low temperature - the JT valve is a flow resistance solidified structure, which cannot instantly and efficiently adjust the refrigerant flow, has low working efficiency, and the sample cannot achieve a large range of temperature changes. Test.

[0005] Based on the above situation, a continuous flow differential decompression ultra-high vacuum low-temperature device is needed, which can not only provide a continuous ultra-low temperature and ultra-high vacuum environment, but also reduce vibration of the ultra-low temperature, ultra-high vacuum, and ultra-low vibration device to solve the current problems. Summary of the invention

[0006] In order to overcome the deficiencies of the prior art, the present invention provides a continuous flow differential decompression ultra-high vacuum low temperature device, which has the advantage of reducing vibration transmission of ultra-low temperature, ultra-high vacuum and ultra-low vibration devices.

[0007] To achieve the above object, the present invention provides the following technical solution: a continuous flow differential decompression ultra-high vacuum low temperature device, comprising a low temperature thermostat and a refrigeration module, characterized in that:

[0008] The cryostat comprises a cryogenic chamber, a guide tube and a shell, wherein:

[0009] The cryogenic chamber includes a protective cover, a cold screen with a cylindrical structure is fixed in the protective cover, a 2K cell and a 1.3K cell are fixed in the cold screen, the 2K cell is located above the 1.3K cell, and the two are separated by a partition; a vaporizer is fixed at the bottom of the cold screen, a sample holder for holding samples is fixed below the vaporizer, the vaporizer is a matrix-type porous structure, one end of the vaporizer is connected to the bottom of the 1.3K cell, and the other end of the vaporizer is connected to the 2K cell through a liquid guide tube, the liquid guide tube is connected to the valve body at the bottom of the flow switch, and the valve body is adjusted to control the flow rate of the fluid in the liquid guide tube;

[0010] The conduit is arranged vertically, the bottom end of the conduit is located in the 2K pool, and the top end of the conduit extends above the protective cover;

[0011] The tube shell is coated on the outside of the catheter, and the tube shell penetrates into the protective cover, and a sealing flange is provided at the junction of the tube shell and the protective cover; the tube shell includes an upper tube shell and a lower tube shell, and the lower tube shell is coated on the outside of the 2K pool and the 1.3K pool, and at the same time, the catheter in the low-temperature chamber is coated; the upper tube shell is coated on the outside of the catheter, and the upper tube shell and the lower tube shell are connected by an adapter plate, and the upper tube shell is connected to the 2K pool;

[0012] An air extraction port is provided on the outer wall of the tube shell, and the air extraction port includes a first air extraction port and a second air extraction port. The first air extraction port is connected to the 1.3K pool through an air extraction pipe; the second air extraction port is connected to the inner space of the upper tube shell;

[0013] The refrigeration module includes a compressor, a refrigerator and a circulating pump group, among which:

[0014] The input end of the circulation pump group is connected to the exhaust port to transport the helium extracted from the low-temperature thermostat to the refrigerator; the compressor is connected to the refrigerator to ensure the normal operation of the refrigerator and provide an initial low-temperature environment; the output end of the refrigerator is connected to the top of the catheter to transport the cooled liquid helium back to the low-temperature chamber.

[0015] Furthermore, an instrument group, an air extraction port, and a defroster are fixed to the outer wall of the tube shell. The defroster, the instrument group, and the low-temperature cavity are arranged in sequence from top to bottom.

[0016] Furthermore, the defroster is arranged on the outer wall of the upper tube shell and wraps the second air extraction port.

[0017] Furthermore, the conduit and the exhaust pipe are both made of stainless steel.

[0018] Furthermore, the instrument group is arranged on the outer wall of the upper tube shell, and the instrument group is provided with an electrical interface, a vacuum port and a spare interface;

[0019] One end of the vacuum port is communicated with a closed space composed of the lower tube shell, the two-stage low-temperature pool and the protective cover, and the other end is communicated with an external pump group.

[0020] Furthermore, a flow switch is provided on the top of the tube shell, and the flow switch includes a needle valve knob, a connecting rod and a valve body, and is arranged from top to bottom, and the flow switch extends downward to the 1.3K pool of the low temperature chamber, specifically:

[0021] The needle valve knob is located at the top of the upper tube shell, the connecting rod runs through the entire tube shell, the valve body is embedded in the partition between the 2K pool and the 1.3K pool, and a small hole is opened in the 2K pool part of the valve body.

[0022] Furthermore, heat-insulating baffles are arranged at equal intervals inside the tube shell, and the connecting rod, the conduit, and the exhaust pipe all pass through the heat-insulating baffles.

[0023] Furthermore, a thermometer and a heater are installed at the sample holder and connected to the temperature control module through an electrical connector.

[0024] Furthermore, the sealing flange is a knife-edge flange.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The refrigeration module and the cryostat are designed independently, which can provide low-temperature helium to the cryostat while avoiding the vibration generated by the refrigerator during operation from being transmitted to the cryostat, thereby greatly reducing the vibration of the cryostat;

[0027] 2. Secondary cooling design: low-temperature helium undergoes initial throttling and cooling after passing through the valve body, and then enters the vaporizer through the liquid guide tube for vaporization and secondary cooling, with obvious cooling effect;

[0028] 3. The differential decompression design extracts the low-temperature helium that returns to the 1.3K pool after vaporization, increases the pressure difference environment required at both ends of the valve body, thereby further enhancing the throttling and cooling effect. Combined with the temperature control module, the temperature at the sample holder is <1.3K-500K;

[0029] 4. The low temperature thermostat has a compact structure and strong compatibility, suitable for many applications BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the overall structure of the device of the present invention;

[0031] Figure 2 It is a schematic diagram of the structure of the low temperature thermostat in the present invention;

[0032] Figure 3 is a side view of a cryostat in the present invention;

[0033] Figure 4 This is a schematic diagram of the structure of the low-temperature chamber of the present invention;

[0034] In the figure, 1, refrigeration module; 101, compressor; 102, refrigerator; 103, low temperature transmission pipeline; 104, helium pipeline; 105, circulation pump group; 106, flow meter; 2. Low-temperature thermostat; 3. Temperature control module; 4. Catheter; 5. Flow switch; 501. Needle valve knob; 502. Connecting rod; 503. Valve body; 6. Exhaust port; 601. First exhaust port; 602. Second exhaust port; 7. Instrument group; 701. Electrical interface; 702. Vacuum port; 8. Shell; 801. Upper shell; 802. Lower shell; 9. Low-temperature chamber; 901. Protective cover; 902. Cold shield; 903. 2K cell; 904. 1.3K cell; 905. Vaporizer; 906. Sample holder; 907. Liquid guide tube; 10. Exhaust pipe; 11. Defroster; 12. Insulation baffle; 13. Sealing flange; 14. Adapter plate. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] like Figures 1 to 4 As shown, a continuous flow differential decompression ultra-high vacuum low temperature device includes a low temperature thermostat 2 and a refrigeration module 1, wherein:

[0037] The cryostat 2 comprises a cryogenic chamber 9, a guide tube 4 and a tube shell 8, wherein:

[0038] The cryogenic chamber 9 includes a protective cover 901, in which a cold shield 902 of a cylindrical structure is fixed, in which a 2K cell 903 and a 1.3K cell 904 are fixed, and the 2K cell 903 is located above the 1.3K cell 904, and the two are separated by a partition; a vaporizer 905 is fixed at the bottom of the cold shield 902, and a sample holder 906 for holding samples is fixed below the vaporizer 905, and a thermometer and a heater are installed at the sample holder 906 and connected to the temperature control module 3 through an electrical connector. The vaporizer 905 is a matrix-type porous structure, one end of the vaporizer 905 is connected to the bottom of the 1.3K cell 904, and the other end of the vaporizer 905 is connected to the 2K cell 903 through a liquid guide tube 907, and the liquid guide tube 907 is connected to the valve body 503 at the bottom of the flow switch 5, and the valve body 503 is adjusted to control the flow rate of the fluid in the liquid guide tube 907;

[0039] The conduit 4 is vertically arranged, the bottom end of the conduit 4 is located in the 2K pool 903, and the top end of the conduit 4 extends to above the protective cover 901;

[0040] The tube shell 8 is coated on the outside of the conduit 4, and the tube shell 8 penetrates into the protective cover 901, and a sealing flange 13 is provided at the junction of the tube shell 8 and the protective cover 901, and the sealing flange 13 is a knife-edge flange compatible with ultra-high vacuum; the tube shell 8 includes an upper tube shell 801 and a lower tube shell 802, and the lower tube shell 2 is coated on the outside of the 2K pool 903 and the 1.3K pool 904, and the conduit 4 in the low-temperature chamber 9 is coated at the same time; the upper tube shell 801 is coated on the outside of the conduit 4, and the upper tube shell 801 and the lower tube shell 802 are connected by an adapter plate 14, and the upper tube shell 801 is connected to the 2K pool 903;

[0041] The outer wall of the tube shell 8 is fixed with an instrument group 7, an air suction port 6, and a defroster 11. The defroster 11, the instrument group 7, and the low-temperature chamber 9 are arranged in sequence from top to bottom. The defroster 11 is arranged on the outer wall of the upper tube shell 801 and wraps the second air suction port 602. The conduit 4 and the air suction pipe 10 are both made of stainless steel. The instrument group 7 is arranged on the outer wall of the upper tube shell 801, and the instrument group 7 is provided with an electrical interface 701, a vacuum port 702 and a spare interface; one end of the vacuum port 702 is connected to the closed space composed of the lower tube shell 802, the two-stage low-temperature pool and the protective cover 901, and the other end is connected to the external pump group.

[0042] An air extraction port 6 is provided on the outer wall of the tube shell 8. The air extraction port 6 includes a first air extraction port 601 and a second air extraction port 602. The first air extraction port 601 is connected to the 1.3K pool 904 through the air extraction pipe 10; the second air extraction port 602 is connected to the inner space of the upper tube shell 801;

[0043] A flow switch 5 is provided on the top of the tube shell 8. The flow switch 5 includes a needle valve knob 501, a connecting rod 502 and a valve body 503, and is arranged from top to bottom. The flow switch 5 extends downward to the 1.3K pool 904 of the low-temperature chamber 9. Specifically: The needle valve knob 501 is located on the top of the upper shell 801, the connecting rod 502 runs through the entire tube shell 8, the valve body 503 is embedded in the partition between the 2K pool 903 and the 1.3K pool 904, and the valve body 503 has a small hole in the 2K pool 903.

[0044] Insulating baffles 12 are arranged at equal intervals inside the tube shell 8 , and the connecting rod 502 , the guide tube 4 , and the exhaust pipe 10 all pass through the insulating baffles 12 .

[0045] The refrigeration module 1 includes a compressor 101, a refrigerator 102 and a circulation pump group 105, wherein: the input end of the circulation pump group 105 is connected to the exhaust port 6 to transport the liquid helium in the low-temperature thermostat 2 to the refrigerator 102; the compressor 101 is connected to the refrigerator 102 to cool the liquid helium in the refrigerator 102; the output end of the refrigerator 102 is connected to the top end of the conduit 4 to transport the cooled liquid helium back to the low-temperature chamber 9.

[0046] The working principle and use process of the present invention:

[0047] See also Figure 1-4 A continuous flow differential decompression ultra-high vacuum low temperature device, including a low temperature thermostat 2, a refrigeration module 1 and a temperature control module 3. The low temperature thermostat 2 adopts ultra-high vacuum materials and processes, is compatible with ultra-high vacuum environments, and can be baked to 200°C. The low temperature thermostat 2 includes a conduit 4, a flow switch 5, an exhaust port 6, an instrument group 7, a tube shell 8, a low temperature cavity 9, and an exhaust pipe 10. The refrigeration module 1 includes a refrigerator 102, a compressor 101, a low temperature transmission pipeline 103, a helium pipeline 104, and a circulating pump group 1 05 and flowmeter 106, the refrigeration module 1 is connected to the low-temperature thermostat 2 to form a closed loop, and the temperature control module 3 is electrically connected to the low-temperature thermostat 2. Specifically, the low-temperature transmission pipeline 103 is connected with the catheter 4, the low-temperature cavity 9, the exhaust port 6, and the helium pipeline 104 in sequence to form a closed loop, and a group of circulating pumps and flowmeters 106 are respectively arranged near the first exhaust port 601 and the second exhaust port 602. The pumping speed of the circulating pump at the first exhaust port 601 is greater than the pumping speed of the circulating pump at the second exhaust port 602.

[0048] like Figure 2-Figure 4 , wherein the tube shell 8 is divided into an upper tube shell 801 and a lower tube shell 802, which are connected in the middle by an adapter plate 14. Insulating baffles 12 are arranged at equal intervals inside the tube shell 8 to reduce the influence of room temperature heat radiation on the low temperature environment of the sample holder 906. The guide tube 4, the flow switch 5 and the exhaust pipe 10 are wrapped by the tube shell 8, penetrate the insulating baffle 12 and extend downward into the low temperature cavity 9; the outer wall of the tube shell 8 is provided with an instrument group 7, an exhaust port 6, and a defroster 11; the defroster 11, the instrument group 7, and the low temperature cavity 9 are arranged in sequence from top to bottom, and the low temperature cavity 9 is arranged at the lower end of the tube shell 8 through a sealing flange 13;

[0049] The conduit 4 is made of stainless steel, and the cryogenic transmission pipeline 103 of the refrigeration module 1 can be inserted into the conduit 4 to transmit liquid helium to the cryostat 2 .

[0050] The exhaust port 6 includes a first exhaust port 601 and a second exhaust port 602. The first exhaust port 601 is connected to the 1.3K pool 904 through the exhaust pipe 10; the second exhaust port 602 is connected to the internal space of the upper tube shell 801; the exhaust pipe 10 is made of stainless steel, and the vaporized low-temperature helium is extracted along the exhaust pipe 10.

[0051] The temperature of the extracted low-temperature helium is much lower than the room temperature. By arranging a defroster 11 on the outer wall of the upper tube shell 801, frost and condensed water droplets are prevented from forming near the air extraction port 6. The defroster 11 also covers the second air extraction port 602.

[0052] The instrument group 7 is provided with an electrical interface 701, a vacuum port 702 and a spare interface. One end of the electrical interface 701 is connected to the temperature control module 3 through a test cable, and the other end is connected to the thermometer and heater at the sample holder 906. It is also connected to the sample to transmit the sample signal. The vacuum port 702 is connected to the external pump group to vacuum the space in the protective cover 901 to provide the required environment for sample testing. The spare interface is usually sealed with a blind flange, and the joint can be changed according to the subsequent equipment upgrade requirements.

[0053] The flow switch 5 includes a needle valve knob 501, a connecting rod 502 and a valve body 503, which are arranged in sequence from top to bottom. The needle valve knob 501 is located at the top of the tube shell 8, the connecting rod 502 runs through the entire tube shell 8, the valve body 503 is embedded in the partition between the 2K pool 903 and the 1.3K pool 904, and the valve body 503 has a small hole in the 2K pool 903. Cryogenic helium can enter the liquid guide tube 907 from the 2K pool 903 through the small hole. The flow rate of cryogenic helium entering the valve body 503 can be controlled by adjusting the needle valve knob 501, thereby achieving the effect of adjusting the temperature.

[0054] like Figure 4 As shown, the cryogenic chamber 9 includes a protective cover 901, a cold shield 902, a 2K cell 903, a 1.3K cell 904, a vaporizer 905 and a sample holder 906; the 2K cell 903, the 1.3K cell 904, the vaporizer 905 and the sample holder 906 are arranged in sequence from top to bottom, and the protective cover 901 and the cold shield 902 are arranged in sequence from outside to inside.

[0055] The protective cover 901 is installed on the bottom surface of the sealing flange 13. The sealing flange 13 is specifically a knife-edge flange with good sealing performance. The interior of the protective cover 901 is an ultra-high vacuum environment. On the one hand, it provides solid protection for the cryostat 2, and on the other hand, it can effectively reduce the impact of room temperature thermal radiation on the low temperature environment;

[0056] The cold shield 902 is an open cylindrical structure and is installed on the bottom surface of the adapter plate 14;

[0057] The 2K pool 903 and the 1.3K pool 904 are closed cavities and are independent of each other, separated by a partition in the middle, and low-temperature helium can enter the liquid guide tube 907 from the 2K pool 903 through the small hole in the valve body 503;

[0058] The 2K pool 903 is connected to the space inside the tube shell 8 through the top gap, and the low-temperature helium in the pool flows upward along the tube wall under the pumping action of the second exhaust port 602;

[0059] The 1.3K cell 904 is a funnel-shaped structure, and the valve body 503 is connected to the vaporizer 905 through a liquid guide tube 907; the liquid guide tube 907 is a stainless steel capillary; the vaporizer 905 is a matrix-type porous structure, one end of which is connected to the liquid guide tube 907, and the other end is connected to the 1.3K cell 904; the low-temperature helium enters the vaporizer 905 along the liquid guide tube 907, and the vaporized helium enters the 1.3K cell 904 and flows out of the vacuum tube 10 under the pumping action of the first vacuum port 601; by adding the 1.3K cell 904 and further evacuating it, the pressure difference at both ends of the valve body 503 is increased, the throttling effect of the low-temperature helium is further improved, and the temperature at the sample holder 906 is further reduced.

[0060] A thermometer and a heater are installed at the sample holder 906 and are connected to the temperature control module 3 via an electrical connector on the instrument group 7 .

[0061] When the system is working, first follow Figure 1 Connect the modules of the system so that the cryogenic transmission pipeline 103 is connected to the conduit 4, the first and second air extraction ports 602 are connected to the helium pipeline 104 after passing through a group of circulation pumps and flow meters 106 respectively, and the temperature control module 3 is electrically connected to the cryogenic thermostat.

[0062] Next, a vacuum environment is prepared, and a vacuum pump is used to evacuate the cryostat 2 and the refrigeration module 1 .

[0063] Then, the low-temperature thermostat 2 is cooled, and the compressor 101, the refrigerator 102 and the circulating pump group 105 are started. The circulating pump group 105 drives the helium to circulate between the refrigeration module 1 and the low-temperature thermostat 2, and the pumping speed of the first pumping port 601 is greater than the pumping speed of the second pumping port 602. After the helium enters the refrigeration module 1 and is liquefied, the low-temperature helium is introduced into the 2K pool 903 through the super-insulation pipeline and the conduit 4. The flow switch 5 is fine-tuned by observing the reading of the flow meter 106. At this time, the low-temperature helium enters the vaporizer 905 through the valve body 503 and the liquid guide tube 907. After throttling and cooling of the vaporizer 905, the temperature of the 1.3K pool 904 is further reduced to <1.3K. The temperature at the sample holder 906 can be subjected to a temperature change test of <1.3K-500K under the action of the temperature control module 3. The cryostat 2 vaporizes the liquid helium transmitted from the refrigeration module 1 in the vaporizer 905. On this basis, combined with the throttling effect of the flow switch 5 and the differential pressure reduction design at the 1.3K pool 904, the cryostat 2 can change and control the temperature in a wider temperature range. The independent structure ensures low vibration characteristics and greatly saves the use cost.

[0064] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0065] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A continuous flow differential decompression ultra-high vacuum cryogenic device, comprising a cryostat (2) and a refrigeration module (1), characterized in that: The cryostat (2) comprises a cryostat chamber (9), a guide tube (4) and a tube shell (8), wherein: The low temperature chamber (9) comprises a protective cover (901), a cold shield (902) with a cylindrical structure is fixed in the protective cover (901), a 2K pool (903) and a 1.3K pool (904) are fixed in the cold shield (902), the 2K pool (903) is located above the 1.3K pool (904), and the two are separated by a partition; a vaporizer (905) is fixed at the bottom of the cold shield (902), and a container for containing A sample holder (906) for holding a sample, a vaporizer (905) having a matrix-type porous structure, one end of the vaporizer (905) being connected to the bottom of the 1.3K cell (904), and the other end of the vaporizer (905) being connected to the 2K cell (903) via a liquid guide tube (907), the liquid guide tube (907) being connected to a valve body (503) at the bottom of a flow switch (5), and the flow rate of the fluid in the liquid guide tube (907) being controlled by adjusting the valve body (503); The conduit (4) is arranged vertically, the bottom end of the conduit (4) is located in the 2K pool (903), and the top end of the conduit (4) extends above the protective cover (901); The tube shell (8) is coated on the outside of the conduit (4), the tube shell (8) penetrates into the protective cover (901), and a sealing flange (13) is provided at the junction of the tube shell (8) and the protective cover (901); the tube shell (8) comprises an upper tube shell (801) and a lower tube shell (802), the lower tube shell (802) is coated on the outside of the 2K pool (903) and the 1.3K pool (904), and at the same time coats the conduit (4) in the low-temperature chamber (9); the upper tube shell (801) is coated on the outside of the conduit (4), the upper tube shell (801) and the lower tube shell (802) are connected via an adapter plate (14), and the upper tube shell (801) is connected to the 2K pool (903); An air extraction port (6) is provided on the outer wall of the tube shell (8), the air extraction port (6) comprising a first air extraction port (601) and a second air extraction port (602), the first air extraction port (601) being connected to the 1.3K pool (904) via an air extraction pipe (10); the second air extraction port (602) being connected to the internal space of the upper tube shell (801); The refrigeration module (1) comprises a compressor (101), a refrigerator (102) and a circulation pump group (105), wherein: The input end of the circulation pump group (105) is connected to the exhaust port (6) to transport the helium extracted from the low-temperature thermostat (2) to the refrigerator (102); the compressor (101) is connected to the refrigerator (102) to ensure the normal operation of the refrigerator (102) and provide an initial low-temperature environment; the output end of the refrigerator (102) is connected to the top end of the conduit (4) to transport the cooled liquid helium back to the low-temperature chamber (9).

2. A continuous flow differential decompression ultra-high vacuum low temperature device according to claim 1, characterized in that: An instrument group (7), an air extraction port (6), and a defroster (11) are fixed to the outer wall of the tube shell (8); the defroster (11), the instrument group (7), and the low-temperature chamber (9) are arranged in sequence from top to bottom.

3. A continuous flow differential decompression ultra-high vacuum low temperature device according to claim 2, characterized in that: The defroster (11) is arranged on the outer wall of the upper tube shell (801) and surrounds the second air extraction port (602).

4. A continuous flow differential decompression ultra-high vacuum low temperature device according to claim 3, characterized in that: The conduit (4) and the exhaust pipe (10) are both made of stainless steel.

5. A continuous flow differential decompression ultra-high vacuum low temperature device according to claim 4, characterized in that: The instrument group (7) is arranged on the outer wall of the upper tube shell (801), and an electrical interface (701), a vacuum port (702) and a spare interface are arranged on the instrument group (7); One end of the vacuum port (702) is in communication with a closed space formed by the lower tube shell (802), the two-stage low-temperature pool and the protective cover (901), and the other end is in communication with an external pump group.

6. A continuous flow differential decompression ultra-high vacuum low temperature device according to claim 5, characterized in that: A flow switch (5) is arranged on the top of the tube shell (8). The flow switch (5) comprises a needle valve knob (501), a connecting rod (502) and a valve body (503), and is arranged from top to bottom. The flow switch (5) extends downward into the 1.3K pool (904) of the low-temperature chamber (9). Specifically: The needle valve knob (501) is located at the top of the upper tube shell (801), the connecting rod (502) runs through the entire tube shell (8), the valve body (503) is embedded in the partition between the 2K pool (903) and the 1.3K pool (904), and the valve body (503) has a small hole in the 2K pool (903).

7. A continuous flow differential decompression ultra-high vacuum low temperature device according to claim 6, characterized in that: Heat-insulating baffles (12) are arranged at equal intervals inside the tube shell (8), and the connecting rod (502), the guide tube (4), and the exhaust pipe (10) all pass through the heat-insulating baffles (12).

8. The continuous flow differential decompression ultra-high vacuum low temperature device according to claim 1, characterized in that: A thermometer and a heater are installed at the sample holder (906) and are connected to the temperature control module (3) via an electrical connector.

9. The continuous flow differential decompression ultra-high vacuum low temperature device according to claim 1, characterized in that: The sealing flange (13) is a knife-edge flange.

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