A cryostat for scanning electron microscope

Abstract

The present invention proposes a cryostat for a scanning electron microscope, comprising: a cryostat body, a cryostat cold end, and a drive device; wherein the cryostat body is connected to the cryostat cold end via a hollow tube; the drive device is connected to the hollow tube and is configured to drive a portion of the hollow tube proximate the cryostat cold end to perform axial reciprocating movement, thereby driving the cryostat cold end to connect or disconnect with a sample stage of the scanning electron microscope; wherein, when the cryostat cold end is connected to the sample stage, the cryostat body provides cooling to the sample stage via the cryostat cold end. The present invention can precisely control the temperature environment within the sample stage, preventing any temperature fluctuations caused by environmental factors, meeting various complex experimental requirements, and ensuring the accuracy, stability, and reliability of experimental results.

Description

Technical Field

[0001] The invention belongs to the technical field of low-temperature refrigeration, and in particular relates to a low-temperature thermostat for a scanning electron microscope. Background Art

[0002] The scanning electron microscope (SEM) is a common laboratory device that allows for high-magnification microscopic observation of samples without damaging them. To ensure the accuracy and stability of the SEM's observations, the sample stage needs to be kept at an extremely low temperature (around -260 degrees Celsius). At this point, the cryostat becomes particularly important. The application of the cryostat in the SEM is generally in the following aspects: 1. Providing a stable low-temperature environment: The cryostat can control the temperature of the sample stage to keep it at an extremely low temperature. This helps to improve the observation accuracy and stability of the SEM. 2. Protecting the sample: The low-temperature environment can slow down the sample's decay process, thereby protecting the sample from damage. 3. Improving the observation effect: In a low-temperature environment, the physical and chemical properties of the sample change, which can help scientists observe the sample's morphology and structure more accurately. However, most of the existing cryostats are used on optical electron microscopes. Since the working principles of scanning electron microscopes and optical electron microscopes are different, the existing cryostats cannot be directly applied to scanning electron microscopes. In addition, the sample stage of the scanning electron microscope needs to move in the three-axis directions of X, Y, and Z and the circumferential direction during use, which requires the low-temperature cold stage connected to the sample stage to move with it. If a rigid connection is used, the sample stage will not be able to move normally. Therefore, professional structural design is required for the cryostats used on scanning electron microscopes to match the application scenarios of scanning electron microscopes. Summary of the Invention

[0003] The object of the present invention is to provide a low temperature thermostat for a scanning electron microscope in order to address the deficiencies of the prior art.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solution: a low-temperature thermostat for a scanning electron microscope, comprising: a low-temperature thermostat body, a low-temperature thermostat cold end and a driving device; wherein the low-temperature thermostat body is connected to the low-temperature thermostat cold end through a hollow tube body; the driving device is connected to the hollow tube body, and is used to drive the part of the hollow tube body close to the low-temperature thermostat cold end to move axially, thereby driving the low-temperature thermostat cold end to be connected to or separated from the sample stage of the scanning electron microscope; wherein, when the low-temperature thermostat cold end is connected to the sample stage, the low-temperature thermostat body provides cooling to the sample stage through the low-temperature thermostat cold end.

[0005] In a specific embodiment, the driving device includes: a power unit, a screw rod, a first support plate, a second support plate and an elastic tube body; wherein the output end of the power unit is fixedly connected to the first end of the screw rod; the position of the screw rod close to the first end is rotatably connected to the first support plate, and the second end of the screw rod passes through the first support plate and is threadedly connected to the second support plate; the elastic tube body is axially arranged between the first support plate and the second support plate, the first end of the elastic tube body is connected to the side of the hollow tube body away from the cold end of the low-temperature thermostat through the first support plate, and the second end of the elastic tube body is connected to the side of the hollow tube body close to the cold end of the low-temperature thermostat through the second support plate.

[0006] In a specific embodiment, the driving device further includes an axial guide rail, a first end of the axial guide rail is fixedly connected to the first support plate, and a second end of the axial guide rail is slidably connected to the second support plate.

[0007] In a specific embodiment, the axial guide rail includes a plurality of axial guide rods, and the plurality of axial guide rods are respectively arranged on the upper and lower sides of the elastic tube body.

[0008] In a specific embodiment, the elastic tube body includes an elastic metal tube.

[0009] In a specific embodiment, the power unit includes a motor.

[0010] In a specific embodiment, the sample stage includes: a sample moving platform and a sample holder fixedly connected to the sample moving platform, and the sample holder is detachably connected to the cold end of the cryostat.

[0011] In a specific embodiment, the sample holder is connected to the cold end of the cryostat via a flexible connecting pipe, a first end of the flexible connecting pipe is fixedly connected to the sample holder, and a second end of the flexible connecting pipe is connected to the cold end of the cryostat via a pipe joint.

[0012] In a specific embodiment, the cryostat cold end and the pipe joint are detachably connected together.

[0013] In a specific embodiment, the pipe connector is placed on a fixed column and fixedly connected to the fixed column, and the fixed column is fixedly connected to the sample moving platform.

[0014] In a specific embodiment, a first thermal insulation layer is provided on the contact surface between the fixed column and the pipe joint.

[0015] In a specific embodiment, a second thermal insulation layer is provided on the contact surface between the fixed column and the sample moving platform.

[0016] In a specific embodiment, the sample moving platform is connected to the sample holder via a sample holder supporting plate, and the sample holder supporting plate is fixedly connected to the sample moving platform.

[0017] In a specific embodiment, the sample holder support plate is made of heat-insulating material.

[0018] In a specific embodiment, a temperature sensor and a heater are provided on the sample holder.

[0019] In a specific embodiment, an instrument housing is provided on one end of the hollow tube close to the cryostat body.

[0020] In a specific embodiment, an electrical connector is provided on the instrument housing.

[0021] In a specific embodiment, the sample stage and the cryostat cold end are both arranged in the electron microscope cavity.

[0022] In a specific embodiment, the side wall of the scanning electron microscope cavity is connected to the instrument housing through a vacuum cavity, and the hollow tube between the instrument housing and the side wall of the scanning electron microscope cavity and the driving device are both arranged in the vacuum cavity.

[0023] In a specific embodiment, the cryostat body is provided with an inlet and an outlet.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The cryostat of the present invention performs heat exchange with the sample stage at the cold end of the cryostat, which can accurately control the temperature environment inside the sample stage and prevent any temperature fluctuations caused by environmental factors. The temperature inside the sample stage can meet the observation requirements of the scanning electron microscope and the temperature inside the sample stage can be maintained in a stable state, thereby ensuring the observation accuracy of the scanning electron microscope and the accuracy, stability and reliability of the observation results.

[0026] 2. The cryostat of the present invention is provided with a driving device to drive the portion of the hollow tube body close to the cold end of the cryostat to perform axial reciprocating movement, thereby driving the cold end of the cryostat to connect or separate with the sample stage of the scanning electron microscope. The method is simple, efficient, stable and reliable.

[0027] 3. The cold end of the cryostat and the pipe joint of the present invention can be freely connected or separated. When the sample stage does not need the cryostat to provide cooling, the cold end of the cryostat and the pipe joint are connected by the driving device, which effectively ensures the free opening and closing state of the scanning electron microscope door and is completely unaffected by the cryostat. When the sample stage needs the cryostat to provide cooling, the cold end of the cryostat and the pipe joint are connected by the driving device, which ensures the supply of cooling to the sample stage, which is convenient and efficient.

[0028] 4. The present invention is provided with a flexible connecting pipe, which can transfer the cold energy from the cold end of the cryostat to the sample holder. At the same time, the flexible characteristics of the flexible connecting pipe are utilized. When the cryostat remains fixed, the sample holder can move freely on the sample moving platform without interrupting the connection between it and the cryostat, thereby ensuring the normal transfer of cold energy.

[0029] 5. The present invention is provided with a fixed column, which can withstand the mechanical stress generated when the pipe joint is fixedly connected to the cold end of the cryostat, thereby ensuring good contact between the pipe joint and the cold end of the cryostat.

[0030] 6. The instrument housing of the low-temperature thermostat of the present invention is connected to the side wall of the scanning electron microscope cavity through a vacuum cavity, which can not only prevent the influence of air convection on the temperature of the low-temperature thermostat and reduce heat leakage, but also meet the free movement of the sample stage and facilitate the opening and closing of the front panel of the scanning electron microscope.

[0031] 7. The cryostat of the present invention has a simple structure, is easy to use, and is economical, and has a rich effect on the application scenarios of the cryostat. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A schematic structural diagram showing a specific embodiment of the connection between the cryostat and the sample stage of the present invention is shown;

[0033] Figure 2 A schematic structural diagram showing another specific embodiment of the connection between the cryostat and the sample stage of the present invention is shown;

[0034] Figure 3 A partial structural diagram of a specific embodiment of the connection between the cryostat and the sample stage of the present invention is shown;

[0035] Figure 4 A schematic structural diagram of a specific embodiment of a driving device for a low-temperature thermostat according to the present invention is shown.

[0036] Among them, 1- low-temperature thermostat body; 11- inlet; 12- outlet; 2- low-temperature thermostat cold end; 3- driving device; 31- power unit; 32- screw rod; 33- first support plate; 34- second support plate; 35- elastic tube; 36- axial guide rail; 361- axial guide rod; 4- hollow tube; 5- sample stage; 51- sample moving platform; 52- sample holder; 53- fixed column; 54- sample holder support plate; 6- flexible connecting pipe; 7- pipe joint; 8- instrument housing; 81- electrical connector; 9- electron microscope cavity; 91- side wall; 10- vacuum cavity. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to the embodiments shown in the accompanying drawings.

[0038] The directional terms used in the present invention, such as "front," "rear," "inner," "outer," and "axial," are merely references to the accompanying drawings. Therefore, the directional terms used are for explaining and understanding the present invention, and are not intended to limit the present invention.

[0039] like Figures 1 to 4 As shown, the cryostat for a scanning electron microscope of the present invention comprises: a cryostat body 1, a cryostat cold end 2 and a driving device 3.

[0040] The cryostat body 1 is connected to the cryostat cold end 2 via a hollow tube 4. The cryostat body 1 is the core component of the cryostat.

[0041] The driving device 3 is connected to the hollow tube body 4 and is used to drive the part of the hollow tube body 4 close to the cold end 2 of the cryostat to move axially back and forth, thereby driving the cold end 2 of the cryostat and the sample stage 5 of the scanning electron microscope to be connected or separated. It is simple, efficient and flexible.

[0042] When the cryostat cold end 2 is connected to the sample stage 5, the cryostat body 1 provides cooling to the sample stage 5 through the cryostat cold end 2. The cryostat cold end 2 is the primary location for cooling in the cryostat. Through heat exchange (heat transfer) with the sample stage 5, it transfers heat from the sample stage 5 to the outside, maintaining an extremely low temperature (down to approximately -260°C) and a stable temperature inside the sample stage 5, thereby ensuring the observation accuracy, stability, and reliability of the scanning electron microscope.

[0043] During use, cryogenic liquid (including liquid helium or liquid nitrogen) flows into the cryostat body 1 through the inlet 11, is transported through the hollow tube 4 to the cryostat cold end 2, and undergoes heat exchange with the sample stage 5 at the cryostat cold end 2, maintaining a stable temperature within the sample stage 5. Simultaneously, the cryogenic liquid is converted into gas after the heat exchange and flows out through the outlet 12 of the cryostat body 1. The driving device 3 is capable of driving the portion of the hollow tube 4 near the cryostat cold end 2 to axially reciprocate, thereby causing the cryostat cold end 2 to extend forward (toward the sample stage 5) or retract backward (away from the sample stage 5). When the cryostat cold end 2 extends forward, it is connected to the sample stage 5; when it retracts backward, it separates from the sample stage 5.

[0044] In a specific embodiment, Figures 2-4 As shown, the driving device 3 includes: a power unit 31, a screw rod 32, a first support plate 33, a second support plate 34 and an elastic tube 35.

[0045] The output end of the power unit 31 is fixedly connected to the first end of the screw rod 32 to drive the screw rod 32 to rotate.

[0046] The position of the screw rod 32 close to the first end is rotatably connected to the first support plate 33 , and the second end of the screw rod 32 passes through the first support plate 33 and is threadedly connected to the second support plate 34 .

[0047] The elastic tube body 35 is axially arranged between the first support plate 33 and the second support plate 34. The first end of the elastic tube body 35 is connected to the side of the hollow tube body 4 away from the cold end 2 of the cryostat through the first support plate 33, and the second end of the elastic tube body 35 is connected to the side of the hollow tube body 4 close to the cold end 2 of the cryostat through the second support plate 34.

[0048] After the sample to be observed is mounted on the sample stage 5 and the SEM hatch is closed, the power unit 31 is driven in the forward direction by a control signal. When the power unit 31 rotates forward, it drives the second support plate 34 forward along the screw 32, causing the elastic tube 35 to stretch forward, thereby pushing the portion of the hollow tube 4 near the cryostat cold end 2 axially forward, thereby causing the cryostat cold end 2 to extend forward. When the cryostat cold end 2 extends forward, it connects with the sample stage 5, thereby enabling cooling. After the sample observation experiment is completed, the power unit 31 is driven in the reverse direction by a control signal. When the power unit 31 rotates in the reverse direction, it drives the second support plate 34 backward along the screw 32, causing the elastic tube 35 to retract backward, thereby pulling the portion of the hollow tube 4 near the cryostat cold end 2 axially backward, thereby causing the cryostat cold end 2 to retract backward. When the cold end 2 of the cryostat is retracted backward, it can be separated from the sample stage 5, and then the scanning electron microscope cabin door is opened to facilitate taking out the sample.

[0049] In a specific embodiment, Figures 2-4 As shown, the driving device 3 further includes an axial guide rail 36, a first end of which is fixedly connected to the first support plate 33, and a second end of which is slidably connected to the second support plate 34. The axial guide rail 36 ensures the stability of the reciprocating motion of the second support plate 34 and the elastic tube 35 in the axial direction, preventing deviation in the motion direction.

[0050] In a specific embodiment, Figures 2-4 As shown, the axial guide rail 36 includes multiple axial guide rods 361, which are respectively arranged on the upper and lower sides of the elastic tube body 35, which can further ensure the stability of the reciprocating motion of the second support plate 34 and the elastic tube body 35 in the axial direction, and further prevent the deviation of the motion direction.

[0051] In a specific embodiment, Figures 2-4 As shown, the elastic tube body 35 includes an elastic metal tube that can meet the elasticity requirements, and the wall thickness of the metal tube is relatively large, so it can transport high-pressure gas and / or liquid.

[0052] In a specific embodiment, Figures 2-4 As shown, the power unit 31 includes a motor, which has the advantages of compact structure, high power, high efficiency, low noise and long service life.

[0053] In a specific embodiment, Figures 1 to 3As shown, the sample stage 5 includes a sample moving platform 51 and a sample holder 52 fixedly connected to the sample moving platform 51. The sample holder 52 is detachably connected to the cryostat cold end 2. The cryostat cold end 2 provides cooling to the interior of the sample holder 52, thereby maintaining the interior of the sample holder 52 at an extremely low temperature and maintaining a stable temperature.

[0054] In a specific embodiment, Figures 1 to 3 As shown, the sample holder 52 is connected to the cryostat cold end 2 via a flexible connecting pipe 6. The first end of the flexible connecting pipe 6 is fixedly connected to the sample holder 52, and the second end of the flexible connecting pipe 6 is connected to the cryostat cold end 2 via a pipe joint 7. The flexible connecting pipe 6 can transfer the cold energy from the cryostat cold end 2 to the sample holder 52. At the same time, the flexibility of the flexible connecting pipe 6 allows the sample holder 52 to move freely on the sample moving platform 51 while the cryostat remains fixed, without interrupting its connection with the cryostat, thereby ensuring normal cold energy transfer.

[0055] In a specific embodiment, Figures 1 to 3 As shown, the sample holder 52 is made of high-purity oxygen-free copper material (with an electrical conductivity of about 58 MS / m (millisievert per meter)) and has good thermal conductivity and mechanical properties.

[0056] In a specific embodiment, Figures 1 to 3 As shown, the flexible connecting pipe 6 is made of high-purity oxygen-free copper material with good thermal conductivity and mechanical properties.

[0057] In a specific embodiment, Figures 1 to 3 As shown, the cryostat cold end 2 is detachably connected to the pipe connector 7. When the cryostat cold end 2 is extended forward, it can be connected to the pipe connector 7, thereby connecting the cryostat cold end 2 to the sample holder 52. This allows cold energy to be transferred from the cryostat cold end 2 to the interior of the sample holder 52 through the pipe connector 7 and the flexible connecting pipe 6. When the cryostat cold end 2 is retracted backward, it can be separated from the pipe connector 7, thereby separating the cryostat cold end 2 from the sample holder 52.

[0058] In a specific embodiment, Figures 1 to 3 As shown, the pipe connector 7 is placed on and fixedly connected to the fixed column 53, and the fixed column 53 is fixedly connected to the sample moving platform 51. The fixed column 53 can withstand the mechanical stress generated when the pipe connector 7 is fixedly connected to the cryostat cold end 2, thereby ensuring good contact between the pipe connector 7 and the cryostat cold end 2.

[0059] In a specific embodiment, a first insulation layer is provided on the contact surface between the fixed column 53 and the pipe joint 7. The first insulation layer can prevent the cold energy of the cryostat cold end 2 from being transferred to the fixed column 53, thereby wasting the cold energy.

[0060] In a specific embodiment, a second heat insulating layer is provided on the contact surface between the fixed column 53 and the sample moving platform 51. The second heat insulating layer can further prevent the waste of cooling energy.

[0061] In a specific embodiment, Figures 1 to 3 As shown, the pipe joint 7 is made of high-purity oxygen-free copper material with good thermal conductivity and mechanical properties.

[0062] In a specific embodiment, Figures 1 to 3 As shown, the fixing column 53 is made of stainless steel, aluminum alloy and / or iron alloy, which has high mechanical strength and can better withstand the mechanical stress generated when the pipe joint 7 is fixedly connected to the cold end 2 of the cryostat.

[0063] In a specific embodiment, Figures 1 to 3 As shown, the fixed column 53 is cylindrical or square. The shape of the fixed column 53 can be set according to actual needs.

[0064] In a specific embodiment, Figures 1 to 3 As shown, the sample moving platform 51 is connected to the sample holder 52 via a sample holder support plate 54, which is fixedly connected to the sample moving platform 51. The sample holder support plate 54 ensures that the sample holder 52 can move simultaneously with the sample moving platform 51 and prevents the cold air entering the sample holder 52 from being transferred to the sample moving platform 51.

[0065] In a specific embodiment, Figures 1 to 3 As shown, the sample holder support plate 54 is made of a heat-insulating material with good heat-insulating effect. The heat-insulating material includes nylon, polytetrafluoroethylene, glass fiber reinforced plastic, PEEK (polyetheretherketone) or ceramic.

[0066] In one specific embodiment, a temperature sensor and a heater are provided on the sample holder 52. The temperature sensor can monitor the temperature of the sample holder 52 in real time. When the temperature of the sample holder 52 drops below a desired level, the heater is activated to heat the sample. This temperature control system ensures a stable sample temperature during low-temperature experiments.

[0067] In a specific embodiment, Figures 1 to 3As shown, an instrument housing 8 is provided on one end of the hollow tube 4 close to the cryostat body 1. The instrument housing 8 can be used to install, fix and protect the internal electronic components to prevent damage due to the influence of the external environment.

[0068] In a specific embodiment, Figures 1 to 3 As shown, an electrical connector 81 is provided on the instrument housing 8. The electrical connector 81 is a connecting bridge for all electrical components, and controls various components inside the cryostat through the transmission of electrical signals.

[0069] In a specific embodiment, Figure 1 、 Figure 2 As shown, the sample stage 5 and the cryostat cold end 2 are both disposed in the electron microscope cavity 9. The electron microscope cavity 9 can be used to provide a vacuum environment, thereby preventing air convection from affecting the temperature of the sample holder 52 and reducing heat leakage.

[0070] In a specific embodiment, Figure 1 As shown, the sidewall 91 of the SEM chamber 9 is connected to the instrument housing 8 via a vacuum chamber 10. The hollow tube 4 and the drive device 3 between the instrument housing 8 and the sidewall 91 of the SEM chamber 9 are both disposed within the vacuum chamber 10. The vacuum chamber 10 provides a vacuum environment, preventing air convection from affecting the temperature of the cryostat and reducing heat leakage. Furthermore, placing the cryostat on the side of the SEM chamber 9 allows for the free movement of the sample stage 5 and facilitates the opening and closing of the SEM front panel.

[0071] In a specific embodiment, Figure 1 As shown, the vacuum chamber 10 includes a vacuum cover, which has a simple structure and is easy to use.

[0072] In a specific embodiment, Figures 1 to 3 As shown, the cold end 2 of the cryostat is made of high-purity oxygen-free copper material with good thermal conductivity and mechanical properties.

[0073] In a specific embodiment, Figures 1 to 3 As shown, the cryostat body 1 is made of a double-layer concentric stainless steel round tube.

[0074] When the present invention is in use, the drive device 3 can drive the portion of the hollow tube 4 near the cryostat cold end 2 to perform axial reciprocating movement, thereby driving the cryostat cold end 2 to extend forward and connect with the sample holder 52; or to drive the cryostat cold end 2 to retract backward and separate from the sample holder 52. When the cryostat cold end 2 is connected to the sample holder 52, the cryostat body 1 provides cooling to the sample holder 52 through the cryostat cold end 2, thereby precisely controlling the temperature environment within the sample holder 52, preventing any temperature fluctuations caused by environmental factors, meeting various complex experimental requirements, and ensuring the accuracy, stability, and reliability of experimental results.

[0075] The scope of protection of the present invention is not limited to the above-described embodiments. Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the scope and spirit of the present invention. If such modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A cryostat for a scanning electron microscope, characterized in that include: A cryostat body (1), a cryostat cold end (2), and a drive device (3); wherein, The cryostat body (1) is connected to the cryostat cold end (2) via a hollow tube (4); The driving device (3) is connected to the hollow tube (4) and is used to drive the portion of the hollow tube (4) close to the cold end (2) of the cryostat to perform axial reciprocating movement, thereby driving the cold end (2) of the cryostat to be connected to or separated from the sample stage (5) of the scanning electron microscope; the sample stage (5) includes a sample holder (52) connected to the cold end (2) of the cryostat via a flexible connecting pipe (6), and the flexible connecting pipe 6 is made of high-purity oxygen-free copper material; Wherein, when the cryostat cold end (2) is connected to the sample stage (5), the cryostat body (1) provides cooling to the sample stage (5) through the cryostat cold end (2); The driving device (3) comprises: a first support plate (33), a second support plate (34) and an elastic tube (35); The elastic tube body (35) is axially arranged between the first support plate (33) and the second support plate (34), and the first end of the elastic tube body (35) is connected to the side of the hollow tube body (4) away from the cold end (2) of the cryostat through the first support plate (33), and the second end of the elastic tube body (35) is connected to the side of the hollow tube body (4) close to the cold end (2) of the cryostat through the second support plate (34).

2. The cryostat for a scanning electron microscope according to claim 1, wherein The driving device (3) further includes: a power unit (31) and a screw rod (32); wherein, The output end of the power unit (31) is fixedly connected to the first end of the screw rod (32); The position of the screw rod (32) close to the first end is rotatably connected to the first support plate (33), and the second end of the screw rod (32) passes through the first support plate (33) and is threadedly connected to the second support plate (34).

3. The cryostat for a scanning electron microscope according to claim 2, wherein: The driving device (3) further comprises an axial guide rail (36), wherein a first end of the axial guide rail (36) is fixedly connected to the first support plate (33), and a second end of the axial guide rail (36) is slidably connected to the second support plate (34).

4. The cryostat for a scanning electron microscope according to claim 3, wherein The axial guide rail (36) comprises a plurality of axial guide rods (361), and the plurality of axial guide rods (361) are respectively arranged on the upper and lower sides of the elastic tube body (35).

5. The cryostat for a scanning electron microscope according to claim 2, wherein: The elastic tube body (35) comprises an elastic metal tube, and the power unit (31) comprises a motor.

6. The cryostat for a scanning electron microscope according to claim 1, wherein The sample stage (5) comprises: a sample moving platform (51) and a sample holder (52) fixedly connected to the sample moving platform (51); the sample holder (52) is detachably connected to the cold end (2) of the cryostat.

7. The cryostat for a scanning electron microscope according to claim 6, wherein: The sample holder (52) is connected to the cold end (2) of the cryostat via a flexible connecting pipe (6), a first end of the flexible connecting pipe (6) is fixedly connected to the sample holder (52), and a second end of the flexible connecting pipe (6) is connected to the cold end (2) of the cryostat via a pipe joint (7).

8. The cryostat for a scanning electron microscope according to claim 7, wherein The cryostat cold end (2) and the pipe joint (7) are detachably connected together.

9. The cryostat for a scanning electron microscope according to claim 7, wherein: The pipe joint (7) is placed on the fixed column (53) and fixedly connected to the fixed column (53), and the fixed column (53) is fixedly connected to the sample moving platform (51).

10. The cryostat for a scanning electron microscope according to claim 9, wherein A first heat insulating layer is provided on the contact surface between the fixed column (53) and the pipe joint (7), and a second heat insulating layer is provided on the contact surface between the fixed column (53) and the sample moving platform (51).

11. The cryostat for a scanning electron microscope according to claim 7, wherein The sample moving platform (51) is connected to the sample holder (52) via a sample holder supporting plate (54), and the sample holder supporting plate (54) is fixedly connected to the sample moving platform (51).

12. The cryostat for a scanning electron microscope according to claim 11, wherein The sample holder support plate (54) is made of heat-insulating material.

13. The cryostat for a scanning electron microscope according to claim 7, wherein: The sample holder (52) is provided with a temperature sensor and a heater.

14. The cryostat for a scanning electron microscope according to claim 1, wherein An instrument housing (8) is sleeved on one end of the hollow tube (4) close to the cryostat body (1).

15. The cryostat for a scanning electron microscope according to claim 14, wherein An electrical connector (81) is provided on the instrument housing (8).

16. The cryostat for a scanning electron microscope according to claim 14, wherein The sample stage (5) and the cryostat cold end (2) are both arranged in the electron microscope cavity (9).

17. The cryostat for a scanning electron microscope according to claim 16, wherein The side wall (91) of the scanning electron microscope cavity (9) is connected to the instrument housing (8) via a vacuum cavity (10), and the hollow tube (4) and the driving device (3) between the instrument housing (8) and the side wall (91) of the scanning electron microscope cavity (9) are both arranged in the vacuum cavity (10).

18. The cryostat for a scanning electron microscope according to claim 1, wherein The cryostat body (1) is provided with an inlet (11) and an outlet (12).

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