Low vacuum control system and low vacuum control method for electron microscope

Abstract

The present application provides a low vacuum control system and a low vacuum control method for an electron microscope. The low vacuum control system includes a sample chamber, a first vacuum detection element, a first valve body, a voltage stabilizing device, a second valve body, a mechanical pump, and a controller. The first vacuum detection element detects the actual vacuum degree in the sample chamber in real time; the controller compares the actual vacuum degree with a preset target vacuum degree; when the actual vacuum degree is lower than the target vacuum degree, the controller controls the first valve body to open, and the voltage stabilizing device to release gas into the sample chamber, raising the actual vacuum degree to the target vacuum degree; when the actual vacuum degree is higher than the target vacuum degree, the controller controls the second valve body to open, and the mechanical pump to extract gas from the sample chamber, lowering the actual vacuum degree to the target vacuum degree. The present application can accurately control the vacuum degree in the sample chamber, so that the low vacuum environment is no longer a working limitation of the electron microscope, significantly improving the imaging quality and working stability of the electron microscope in a low vacuum environment.

Description

Technical Field

[0001] The present application relates to the technical field of electron microscopes, and in particular to a low vacuum control system and a low vacuum control method for an electron microscope. Background Art

[0002] Electron microscopes play a vital role in many research fields today, including materials science, biomedicine, and nanotechnology. They primarily observe samples by utilizing the fact that electrons are not absorbed or deflected in a vacuum environment. Therefore, the degree of vacuum within an electron microscope can have a significant impact on sample observation.

[0003] However, conventional electron microscopes typically require high vacuum to ensure stable electron beam transmission and image resolution, limiting their ability to observe samples that are conductive and contain no volatile gases. These samples are typically pretreated with methods such as dehydration, drying, freezing, or surface coating with gold. While these samples can be analyzed under an electron microscope, their true appearance cannot be directly observed. Therefore, the high vacuum environment can be a limiting factor for conventional electron microscopes when examining samples that are hydrous, porous, susceptible to electron beam burn, or unsuitable for gold coating. Summary of the Invention

[0004] In view of the above, it is necessary to provide a low vacuum control system and a low vacuum control method for an electron microscope to solve the problem that the high vacuum environment may become a limiting factor for traditional electron microscopes for samples containing water, being porous, not resistant to electron beam burns, and not suitable for gold spraying treatment.

[0005] The embodiment of the present application provides a low vacuum control system for an electron microscope, the low vacuum control system comprising a sample chamber, a first vacuum detection component, a first valve body, a voltage stabilizing device, a second valve body, a mechanical pump, and a controller, the first vacuum detection component being installed in the sample chamber, the voltage stabilizing device being connected to the sample chamber via an air supply pipe, the first valve body being arranged in the air supply pipe, the mechanical pump being connected to the sample chamber via an air extraction pipe, the second valve body being arranged in the air extraction pipe, the controller being electrically connected to the first vacuum detection component, the first valve body, and the second valve body; the first vacuum detection component detecting the low vacuum degree in real time The actual vacuum degree in the sample chamber is fed back to the controller in real time; the controller compares the actual vacuum degree with a preset target vacuum degree; when the actual vacuum degree is lower than the target vacuum degree, the controller controls the first valve body to open and adjusts the opening degree of the first valve body, and the pressure stabilizing device releases gas into the sample chamber until the actual vacuum degree is increased to the target vacuum degree; when the actual vacuum degree is higher than the target vacuum degree, the controller controls the second valve body to open, and the mechanical pump extracts the gas from the sample chamber until the actual vacuum degree is reduced to the target vacuum degree.

[0006] The low vacuum control system of the electron microscope of the present application detects the actual vacuum degree in the sample chamber in real time through the first vacuum detection element, and feeds back to the controller in real time. The controller further compares the actual vacuum degree with the preset target vacuum degree. When the actual vacuum degree is lower than the target vacuum degree, the controller controls the first valve body to open and adjusts the opening degree of the first valve body. The voltage stabilizing device releases gas to the sample chamber until the actual vacuum degree is increased to the target vacuum degree. When the actual vacuum degree is higher than the target vacuum degree, the controller controls the second valve body to open and the mechanical pump extracts the gas from the sample chamber until the actual vacuum degree is reduced to the target vacuum degree. Based on this, the present application can accurately control the vacuum degree in the sample chamber, so that the low vacuum environment is no longer a working limit of the electron microscope, expands the application potential of the electron microscope for the observation of samples containing water, porous materials, not resistant to electron beam burns, and not suitable for gold spraying, and significantly improves the imaging quality and working stability of the electron microscope in a low vacuum environment. In addition, the present application has a simple structure, a compact size, strong practicality, is easy to implement, and has high market application value and scientific research significance.

[0007] In some embodiments, the pressure stabilizing device includes a pressure stabilizing chamber, a vacuum pump, an electromagnetic control valve, an air path installation assembly, and a pagoda joint. The electromagnetic control valve is sealed and connected to the air inlet of the pressure stabilizing chamber; the pagoda joint is sealed and connected to the air outlet of the pressure stabilizing chamber, and are respectively connected to the air intake of the vacuum pump and the air path installation assembly through the air supply pipe; the air path installation assembly is connected to the air inlet of the first valve body through the air supply pipe.

[0008] In some embodiments, the pressure stabilizing device also includes an electrical signal interface, and the electromagnetic control valve is electrically connected to the controller through the electrical signal interface. When the controller controls the electromagnetic control valve to open, air is introduced into the pressure stabilizing chamber, so that the air pressure in the pressure stabilizing chamber is restored to the same air pressure level as the external atmosphere.

[0009] In some embodiments, the pressure stabilizing device also includes an outer frame assembly, the outer frame assembly includes an outer shell, a frame, and a mounting plate, the outer shell is installed on the outside of the frame, the mounting plate is installed on the frame, the pressure stabilizing chamber, the vacuum pump, the electromagnetic control valve, the air path mounting assembly, the pagoda connector, and the electrical signal interface are all installed on the mounting plate.

[0010] In some embodiments, the air circuit mounting assembly includes a mounting block and a quick-change connector. The mounting block is fixed to the mounting plate, and the quick-change connector is installed on the mounting block. The quick-change connector connects the air inlet of the first valve body and the air suction port of the vacuum pump through the air supply pipe.

[0011] In some embodiments, both ends of the quick-change connector are wrapped with "O"-rings.

[0012] In some embodiments, when the vacuum pump is turned on, the gas in the pressure stabilization chamber is pumped out, so that the pressure in the pressure stabilization chamber is reduced to n×10 4 Pa.

[0013] In some embodiments, the pressure stabilizing device also includes a vacuum sealing clamp, the electromagnetic control valve and the air inlet of the pressure stabilizing chamber are sealed connected through the vacuum sealing clamp, and the pagoda joint and the air outlet of the pressure stabilizing chamber are sealed connected through the vacuum sealing clamp.

[0014] In some embodiments, the low vacuum control system also includes a high-pressure gun chamber, a second vacuum detection component, a third valve body, and a molecular pump. The molecular pump includes an upper air pumping port, a lower air pumping port, and an air outlet. The third valve body is arranged between the upper air pumping port and the high-pressure gun chamber, the lower air pumping port is connected to the sample chamber, the second valve body is arranged between the lower air pumping port and the sample chamber, the air outlet is connected to the mechanical pump, the controller is electrically connected to the second vacuum detection component and the third valve body, the second vacuum detection component detects the gun chamber vacuum degree in the high-pressure gun chamber in real time, and feeds back to the controller in real time, and the controller controls the opening / closing of the third valve body according to the gun chamber vacuum degree.

[0015] An embodiment of the present application also provides a low vacuum control method for an electron microscope, which is implemented based on the low vacuum control system of the electron microscope as described in the above embodiment. The low vacuum control method includes: obtaining the actual vacuum level in the sample chamber in real time through a first vacuum detection component; comparing the actual vacuum level with a preset target vacuum level; when the actual vacuum level is lower than the target vacuum level, controlling the first valve body to open, and adjusting the opening degree of the first valve body so that the voltage stabilizing device releases gas into the sample chamber; when the actual vacuum level is higher than the target vacuum level, controlling the second valve body to open, so that a mechanical pump extracts gas from the sample chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings such as the provided drawings can be obtained without creative work.

[0017] Figure 1 It is a structural schematic diagram of a low vacuum control system of an electron microscope provided in one embodiment of the present application.

[0018] Figure 2 yes Figure 1 The structural diagram of the voltage stabilizing device is shown.

[0019] Figure 3 yes Figure 2 The structural diagram of the pressure-stabilizing cavity is shown.

[0020] Figure 4 yes Figure 2 The structural diagram of the gas circuit installation assembly is shown.

[0021] Figure 5 1 is a schematic diagram of the steps of a low vacuum degree control method for an electron microscope provided in one embodiment of the present application.

[0022] Description of main component symbols

[0023] Low vacuum control system 100

[0024] Sample chamber 10

[0025] First vacuum detection part 20

[0026] First valve body 30

[0027] Voltage stabilizing device 40

[0028] Pressure stabilizing chamber 41

[0029] Air outlets 411, 412, 93

[0030] Air Inlet 413

[0031] Vacuum pump 42

[0032] Solenoid control valve 43

[0033] Gas line installation assembly 44

[0034] Mounting block 441

[0035] Quick-change connectors 442 and 443

[0036] Pagoda connector 45, 46

[0037] Electrical signal interface 47

[0038] Vacuum sealing clamp 48

[0039] Outer frame assembly 49

[0040] Shell 491

[0041] Frame 492

[0042] Mounting plate 493

[0043] Second valve body 50

[0044] Mechanical pump 60

[0045] Controller 70

[0046] High pressure gun chamber 80

[0047] Second vacuum detection part 81

[0048] The third valve body 82

[0049] Molecular pump 90

[0050] Upper exhaust port 91

[0051] Lower exhaust port 92 DETAILED DESCRIPTION

[0052] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be understood as limiting the present application.

[0053] In the embodiments of the present application, it should be noted that, unless otherwise expressly specified and limited, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a concrete manner. The following embodiments and features in the embodiments may be combined with each other unless there is a conflict.

[0054] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or connections that can communicate with each other; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to connections within two components or interactions between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0055] In the description of this application, it should be noted that the terms "first," "second," and so on (if any) in the specification and claims of this application are used to distinguish similar objects, rather than to describe a specific order or precedence. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0056] In order to more clearly understand the above-mentioned objectives, features and advantages of the present application, the present application is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features therein can be combined with each other in the absence of conflict.

[0057] Traditional electron microscopes typically require a high vacuum environment to ensure stable electron beam transmission and image resolution. Consequently, the samples they can observe are often limited to those that are conductive and contain no volatile gases. These samples are typically pretreated with methods such as dehydration, drying, freezing, or surface coating with gold. While these samples can be analyzed under an electron microscope, their true appearance cannot be directly observed. Therefore, the high vacuum environment can be a limiting factor for conventional electron microscopes when examining samples that are hydrous, porous, susceptible to electron beam burn, or unsuitable for gold coating.

[0058] In view of the above, it is necessary to provide a low vacuum control system and a low vacuum control method for an electron microscope to solve the problem that the high vacuum environment may become a limiting factor for traditional electron microscopes for samples containing water, being porous, not resistant to electron beam burns, and not suitable for gold spraying treatment.

[0059] See also Figure 1 , is a schematic diagram of the architecture of a low vacuum control system 100 for an electron microscope provided in one embodiment of the present application.

[0060] Specifically, the low vacuum control system 100 includes a sample chamber 10, a first vacuum detector 20, a first valve body 30, a pressure stabilizing device 40, a second valve body 50, a mechanical pump 60, and a controller 70. The first vacuum detector 20 is installed in the sample chamber 10. The pressure stabilizing device 40 is connected to the sample chamber 10 via an air supply line. The first valve body 30 is located in the air supply line. The mechanical pump 60 is connected to the sample chamber 10 via an air extraction line. The second valve body 50 is located in the air extraction line. The controller 70 is electrically connected to the first vacuum detector 20, the first valve body 30, and the second valve body 50. The first vacuum detector 20 detects the actual vacuum level in the sample chamber 10 in real time and provides real-time feedback to the controller 70. The controller 70 compares the actual vacuum level with a preset target vacuum level. When the actual vacuum level falls below the target vacuum level, the controller 70 controls the first valve body 30 to open and adjusts the opening degree of the first valve body 30. The pressure stabilizing device 40 releases gas into the sample chamber 10 until the actual vacuum level reaches the target vacuum level. When the actual vacuum degree is higher than the target vacuum degree, the controller 70 controls the second valve body 50 to open, and the mechanical pump 60 extracts the gas from the sample chamber 10 until the actual vacuum degree is reduced to the target vacuum degree.

[0061] In some embodiments, the controller 70 may be a computer device that may include an input unit for allowing a user to input information (such as a target vacuum level) to the controller 70. The input unit may be a keyboard, a mouse, a microphone, a touch screen, or the like.

[0062] In some embodiments, the first valve body 30 may be an electronic needle valve. The electronic needle valve can quickly and accurately adjust its opening in less than one second using a 0-10V analog voltage signal, thereby achieving high-precision gas flow regulation. It exhibits characteristics such as highly linear response, high repeatability, high resolution, low hysteresis, and fast response. When the controller 70 determines that the actual vacuum level is lower than the target vacuum level, it sends a corresponding voltage signal and pulse time signal to the electronic needle valve based on the target vacuum level, achieving precise adjustment and continuous control of the opening of the electronic needle valve. The pressure stabilizing device 40 is further used to timely release gas into the sample chamber 10, thereby maintaining the desired target vacuum level within the sample chamber 10.

[0063] In some embodiments, the second valve body 50 may be a gate valve. Initially, the gate valve is closed. When the controller 70 determines that the actual vacuum level is higher than the target vacuum level, it sends a voltage signal corresponding to the target vacuum level to the gate valve, controlling the gate valve to open. The mechanical pump 60 then assists in extracting an appropriate amount of excess gas from the sample chamber 10, thereby maintaining the target vacuum level within the sample chamber 10.

[0064] Combine Figure 2 As shown, in some embodiments, the pressure stabilizing device 40 includes a pressure stabilizing chamber 41, a vacuum pump 42, an electromagnetic control valve 43, an air path installation assembly 44, a pagoda connector 45, and a pagoda connector 46. Figure 3 As shown, the electromagnetic control valve 43 is sealedly connected to the air inlet 413 of the pressure-stabilizing chamber 41. The pagoda connector 45 is sealedly connected to the air outlet 411 of the pressure-stabilizing chamber 41. The pagoda connector 46 is sealedly connected to the air outlet 412 of the pressure-stabilizing chamber 41. They are respectively connected to the air intake of the vacuum pump 42 (not shown) and the air path installation assembly 44 through air supply pipes. The air path installation assembly 44 is connected to the air inlet (not shown) of the first valve body 30 through an air supply pipe.

[0065] In some embodiments, the vacuum pump 42 may be a micro vacuum pump.

[0066] Combine Figure 2 As shown, in some embodiments, the pressure stabilizing device 40 further includes an electrical signal interface 47, and the electromagnetic control valve 43 is electrically connected to the controller 70 via the electrical signal interface 47. When the controller 70 controls the electromagnetic control valve 43 to open, air is introduced into the pressure stabilizing chamber 41, so that the air pressure in the pressure stabilizing chamber 41 is restored to the same air pressure level as the external atmosphere.

[0067] In some embodiments, the pressure stabilizing device 40 further includes an outer frame assembly 49. The outer frame assembly 49 includes a housing 491, a frame 492, and a mounting plate 493. The housing 491 is mounted on the outside of the frame 492, the mounting plate 493 is mounted on the frame 492, and the pressure stabilizing chamber 41, vacuum pump 42, electromagnetic control valve 43, gas path mounting assembly 44, pagoda connector 45, pagoda connector 46, and electrical signal interface 47 are all mounted on the mounting plate 493.

[0068] In the above embodiment, the structure of the outer frame assembly 49 ensures the stability and integration of the structure of the voltage stabilizing device 40 and improves the adaptability of the voltage stabilizing device 40.

[0069] Combine Figure 4 As shown, in some embodiments, the air circuit mounting assembly 44 includes a mounting block 441, a quick-change connector 442, and a quick-change connector 443. The mounting block 441 is fixed to the mounting plate 493, and the quick-change connectors 442 and 443 are mounted on the mounting block 441. The quick-change connector 442 is connected to the air inlet of the first valve body 30 (not shown) via an air supply pipe. The quick-change connector 443 is connected to the air intake of the vacuum pump 42 (not shown) via an air supply pipe.

[0070] In some embodiments, both ends of the quick-change connector 442 and the quick-change connector 443 are wrapped with “O”-rings to ensure high sealing performance of the air path installation assembly 44 .

[0071] In the above embodiment, the first valve body 30 is connected via the quick-change connector 442 , and the vacuum pump 42 is connected via the quick-change connector 443 , which improves installation convenience and facilitates disassembly.

[0072] In some embodiments, when the vacuum pump 42 is turned on, the gas in the pressure stabilization chamber 41 is pumped out, so that the pressure in the pressure stabilization chamber 41 is reduced to n×10 4 Pa. Here, "n" is a variable, representing a specific number. Different application scenarios may require different air pressures, so the specific value of "n" will be determined according to the actual situation. For example, if n = 1, the air pressure in the pressure stabilizing chamber 41 will be reduced to 1×10 4 Pa, that is, 10 4 Pa, this value is a relatively low air pressure and is suitable for practical application scenarios that require a high vacuum environment.

[0073] In the above embodiment, air is introduced into the pressure stabilizing chamber 41 through the electromagnetic control valve 43 or the gas in the pressure stabilizing chamber 41 is extracted through the vacuum pump 42, thereby practicing precise control of the air pressure in the pressure stabilizing chamber 41, thereby ensuring the stability of the gas supply of the pressure stabilizing device 40 and being able to adapt to different application scenarios.

[0074] Combine Figure 2As shown, in some embodiments, the pressure stabilizing device 40 further includes a vacuum sealing clamp 48. The electromagnetic control valve 43 is sealedly connected to the air inlet 413 of the pressure stabilizing chamber 41 via the vacuum sealing clamp 48, the pagoda joint 45 is sealedly connected to the air outlet 411 of the pressure stabilizing chamber 41 via the vacuum sealing clamp 48, and the pagoda joint 46 is sealedly connected to the air outlet 412 of the pressure stabilizing chamber 41 via the vacuum sealing clamp 48.

[0075] In the above embodiment, the vacuum sealing clamp 48 has excellent sealing performance, stable and reliable connection, wide applicability, and is easy to install and maintain. The vacuum sealing clamp 48 is used to connect the components, which improves the sealing performance of the voltage stabilizing device 40, thereby ensuring the stable operation of the voltage stabilizing device 40.

[0076] Combine Figure 1 As shown, in some embodiments, the low vacuum control system 100 further includes a high-pressure gun chamber 80, a second vacuum detector 81, a third valve body 82, and a molecular pump 90. The molecular pump 90 includes an upper air pumping port 91, a lower air pumping port 92, and an air outlet 93. The upper air pumping port 91 is connected to the high-pressure gun chamber 80, and the third valve body 82 is disposed between the upper air pumping port 91 and the high-pressure gun chamber 80. The lower air pumping port 92 is connected to the sample chamber 10, and the second valve body 50 is disposed between the lower air pumping port 92 and the sample chamber 10. The air outlet 93 is connected to the mechanical pump 60. The controller 70 is electrically connected to the second vacuum detector 81 and the third valve body 82. The second vacuum detector 81 detects the gun chamber vacuum level in the high-pressure gun chamber 80 in real time and provides real-time feedback to the controller 70. The controller 70 controls the opening / closing of the third valve body 82 based on the gun chamber vacuum level.

[0077] In the above embodiment, the design of the molecular pump 90 can not only ensure that the high-pressure gun chamber 80 maintains a high vacuum environment, thereby extending the life of the filament, but also stably extract the gas in the sample chamber 10 so that the sample chamber 10 maintains the target vacuum degree, thereby reducing the number of times the mechanical pump 60 is used, reducing energy consumption and vibration during system operation, and avoiding the adverse effects of large vibrations caused by the use of the mechanical pump 60 on the use, analysis, and imaging of the electron microscope.

[0078] The low vacuum control system 100 of the electron microscope of the present application detects the actual vacuum degree in the sample chamber 10 in real time through the first vacuum detection part 20, and feeds back to the controller 70 in real time. The controller 70 further compares the actual vacuum degree with the preset target vacuum degree. Further, when the actual vacuum degree is lower than the target vacuum degree, the controller 70 controls the first valve body 30 to open and adjusts the opening degree of the first valve body 30. The voltage stabilizing device 40 releases gas to the sample chamber 10 until the actual vacuum degree is increased to the target vacuum degree. Further, when the actual vacuum degree is higher than the target vacuum degree, the controller 70 controls the second valve body 50 to open and the mechanical pump 60 extracts the gas from the sample chamber 10 until the actual vacuum degree is reduced to the target vacuum degree. Based on this, the present application can accurately control the vacuum degree in the sample chamber 10, so that the low vacuum environment is no longer a working limitation of the electron microscope, expands the application potential of the electron microscope in observing samples containing water, porous materials, not resistant to electron beam burns, and not suitable for gold spraying, and significantly improves the imaging quality and working stability of the electron microscope in a low vacuum environment. In addition, the present invention has a simple structure, compact size, strong practicality, is easy to implement, and has high market application value and scientific research significance.

[0079] See also Figure 5 , is a schematic diagram of the steps of a low vacuum control method for an electron microscope provided in one embodiment of the present application.

[0080] In some embodiments, the schematic diagram of the steps of the low vacuum control method of the electron microscope is applied to the low vacuum control system 100 of the electron microscope in the above embodiment, and the execution body of the low vacuum control method of the electron microscope may be the controller 70 .

[0081] Specifically, the low vacuum control method of the electron microscope includes:

[0082] S10, obtaining the actual vacuum degree in the sample chamber in real time through the first vacuum detection component.

[0083] In some embodiments, before implementing step S10, first, the gas circuit and circuit parts of the pressure stabilizing device 40 need to be correctly installed and connected. Then, the controller 70 needs to be started to open the preset low vacuum control program of the electron microscope. Then, the vacuum pump 42 needs to be started for about 30 seconds. After 30 seconds, the gas in the pressure stabilizing chamber 41 can be pumped out to reduce the pressure in the pressure stabilizing chamber 41 to n×10 4 Pa, finally, the target vacuum degree needs to be input through the input unit of the controller 70.

[0084] S20, comparing the actual vacuum degree with the preset target vacuum degree.

[0085] In some embodiments, the controller 70 compares the actual vacuum level with a preset target vacuum level.

[0086] S30, when the actual vacuum degree is lower than the target vacuum degree, controlling the first valve body to open, and adjusting the opening degree of the first valve body so that the pressure stabilizing device releases gas into the sample chamber until the actual vacuum degree is increased to the target vacuum degree.

[0087] In some embodiments, the first valve body 30 may be an electronic needle valve. The electronic needle valve can quickly and accurately adjust its opening in less than one second using a 0-10V analog voltage signal, thereby achieving high-precision gas flow regulation. It exhibits characteristics such as highly linear response, high repeatability, high resolution, low hysteresis, and fast response. When the controller 70 determines that the actual vacuum level is lower than the target vacuum level, it sends a corresponding voltage signal and pulse time signal to the electronic needle valve based on the target vacuum level, achieving precise adjustment and continuous control of the opening of the electronic needle valve. The pressure stabilizing device 40 is further used to timely release gas into the sample chamber 10, thereby maintaining the desired target vacuum level within the sample chamber 10.

[0088] S40, when the actual vacuum degree is higher than the target vacuum degree, controlling the second valve body to open, so that the mechanical pump extracts the gas from the sample chamber until the actual vacuum degree is reduced to the target vacuum degree.

[0089] In some embodiments, the second valve body 50 may be a gate valve. Initially, the gate valve is closed. When the controller 70 determines that the actual vacuum level is higher than the target vacuum level, it sends a voltage signal corresponding to the target vacuum level to the gate valve, controlling the gate valve to open. The mechanical pump 60 then assists in extracting an appropriate amount of excess gas from the sample chamber 10, thereby maintaining the target vacuum level within the sample chamber 10.

[0090] The low vacuum control method of the electron microscope of the present application detects the actual vacuum degree in the sample chamber 10 in real time through the first vacuum detection part 20, and feeds back to the controller 70 in real time. The controller 70 further compares the actual vacuum degree with the preset target vacuum degree. Further, when the actual vacuum degree is lower than the target vacuum degree, the controller 70 controls the first valve body 30 to open and adjusts the opening degree of the first valve body 30. The voltage stabilizing device 40 releases gas to the sample chamber 10 until the actual vacuum degree is increased to the target vacuum degree. Further, when the actual vacuum degree is higher than the target vacuum degree, the controller 70 controls the second valve body 50 to open and the mechanical pump 60 extracts the gas from the sample chamber 10 until the actual vacuum degree is reduced to the target vacuum degree. Based on this, the present application can accurately control the vacuum degree in the sample chamber 10, so that the low vacuum environment is no longer a working limitation of the electron microscope, expands the application potential of the electron microscope in observing samples containing water, porous materials, not resistant to electron beam burns, and not suitable for gold spraying, and significantly improves the imaging quality and working stability of the electron microscope in a low vacuum environment.

[0091] Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the present application is defined by the appended claims rather than the foregoing description, and all changes that come within the meaning and range of equivalents of the claims are intended to be embraced therein. Any reference to a figure in a claim should not be construed as limiting the claim to which it relates.

[0092] In addition, it is obvious that the word "comprising" does not exclude other submodules or steps, and the singular does not exclude the plural. The multiple submodules or devices stated in this application can also be implemented by one submodule or device through software or hardware.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A low vacuum control system for an electron microscope, characterized in that: The low vacuum control system includes a sample chamber, a first vacuum detection component, a first valve body, a pressure stabilizing device, a second valve body, a mechanical pump, and a controller. The first vacuum detection component is installed in the sample chamber, the pressure stabilizing device is connected to the sample chamber via an air supply pipe, the first valve body is arranged in the air supply pipe, the mechanical pump is connected to the sample chamber via an air extraction pipe, the second valve body is arranged in the air extraction pipe, and the controller is electrically connected to the first vacuum detection component, the first valve body, and the second valve body. The first vacuum detection component detects the actual vacuum degree in the sample chamber in real time and feeds back to the controller in real time; the controller compares the actual vacuum degree with a preset target vacuum degree; when the actual vacuum degree is lower than the target vacuum degree, the controller controls the first valve body to open and adjusts the opening degree of the first valve body, and the pressure stabilizing device releases gas into the sample chamber until the actual vacuum degree is increased to the target vacuum degree; when the actual vacuum degree is higher than the target vacuum degree, the controller controls the second valve body to open, and the mechanical pump extracts the gas from the sample chamber until the actual vacuum degree is reduced to the target vacuum degree.

2. The low vacuum control system for an electron microscope according to claim 1, wherein: The pressure stabilizing device includes a pressure stabilizing chamber, a vacuum pump, an electromagnetic control valve, an air path installation assembly, and a pagoda joint. The electromagnetic control valve is sealedly connected to the air inlet of the pressure stabilizing chamber; the pagoda joint is sealedly connected to the air outlet of the pressure stabilizing chamber, and is respectively connected to the air suction port of the vacuum pump and the air path installation assembly through the air supply pipe; the air path installation assembly is connected to the air inlet of the first valve body through the air supply pipe.

3. The low vacuum control system for an electron microscope according to claim 2, wherein: The pressure stabilizing device also includes an electrical signal interface, and the electromagnetic control valve is electrically connected to the controller through the electrical signal interface. When the controller controls the electromagnetic control valve to open, air is introduced into the pressure stabilizing chamber, so that the air pressure in the pressure stabilizing chamber is restored to the same air pressure level as the external atmosphere.

4. The low vacuum control system for an electron microscope according to claim 3, wherein: The pressure stabilizing device also includes an outer frame assembly, which includes an outer shell, a frame, and a mounting plate. The outer shell is installed on the outside of the frame, and the mounting plate is installed on the frame. The pressure stabilizing chamber, the vacuum pump, the electromagnetic control valve, the air path mounting assembly, the pagoda connector, and the electrical signal interface are all installed on the mounting plate.

5. The low vacuum control system for an electron microscope according to claim 4, wherein: The air circuit installation assembly includes a mounting block and a quick-change connector. The mounting block is fixed to the mounting plate. The quick-change connector is installed on the mounting block. The quick-change connector connects the air inlet of the first valve body and the air suction port of the vacuum pump through the air supply pipe.

6. The low vacuum control system for an electron microscope according to claim 5, wherein: Both ends of the quick-change connector are wrapped with "O"-shaped sealing rings.

7. The low vacuum control system for an electron microscope according to claim 2, wherein: When the vacuum pump is turned on, the gas in the pressure stabilization chamber is pumped out, so that the pressure in the pressure stabilization chamber is reduced to n×10 4 Pa.

8. The low vacuum control system for an electron microscope according to claim 2, wherein: The pressure stabilizing device also includes a vacuum sealing clamp, through which the electromagnetic control valve and the air inlet of the pressure stabilizing chamber are sealed, and the pagoda joint and the air outlet of the pressure stabilizing chamber are sealed.

9. The low vacuum control system for an electron microscope according to claim 1, wherein: The low vacuum control system also includes a high-pressure gun chamber, a second vacuum detection component, a third valve body, and a molecular pump. The molecular pump includes an upper air pumping port, a lower air pumping port, and an air outlet. The third valve body is arranged between the upper air pumping port and the high-pressure gun chamber, the lower air pumping port is connected to the sample chamber, the second valve body is arranged between the lower air pumping port and the sample chamber, the air outlet is connected to the mechanical pump, the controller is electrically connected to the second vacuum detection component and the third valve body, the second vacuum detection component detects the gun chamber vacuum degree in the high-pressure gun chamber in real time, and feeds back to the controller in real time. The controller controls the opening / closing of the third valve body according to the gun chamber vacuum degree.

10. A method for controlling low vacuum degree of an electron microscope, characterized in that: Based on the low vacuum control system of the electron microscope according to any one of claims 1 to 9, the low vacuum control method includes: The actual vacuum degree in the sample chamber is obtained in real time through the first vacuum detection component; comparing the actual vacuum degree with a preset target vacuum degree; When the actual vacuum degree is lower than the target vacuum degree, controlling the first valve body to open, and adjusting the opening degree of the first valve body so that the pressure stabilizing device releases gas into the sample chamber; When the actual vacuum degree is higher than the target vacuum degree, the second valve body is controlled to open, so that the mechanical pump extracts the gas from the sample chamber.

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