High-voltage punch-through assembly and scanning electron microscope with same

Abstract

The invention relates to the technical field of scanning electron microscopes, and discloses a high-voltage punch-through assembly and a scanning electron microscope with the same. The high-voltage punch-through assembly is suitable for being installed on the scanning electron microscope in a sealed mode, and comprises a punch-through sleeve, one end of the punch-through sleeve is provided with a concave socket, the other end of the punch-through sleeve is closed, and the closed end of the punch-through sleeve is fixedly provided with a plurality of conductive electrodes; the conductive cable is installed in the penetrating sleeve, the conductive cable extends in the axial direction of the penetrating sleeve and is suitable for extending out of the conductive cable, and the conductive cable is conductively connected with the conductive electrode; and the connecting piece is fixedly arranged on the outer side wall of the penetrating sleeve, and the connecting piece is suitable for being matched with a matching piece on the scanning electron microscope for vacuum sealing. The high-voltage punch-through assembly is detachably installed on the scanning electron microscope, and when the scanning electron microscope is maintained and carried, the connecting piece and the matching piece are separated from each other, so that the electron gun cavity and the conductive cable are respectively carried and maintained.

Description

Technical Field

[0001] The invention relates to the technical field of scanning electron microscopes, and in particular to a high-voltage feed-through component and a scanning electron microscope having the same. Background Art

[0002] The scanning electron microscope emits an electron beam through an electron gun. After the electron beam is focused by a magnetic lens, it scans the sample surface in a raster-like manner, and detects the signal generated by the interaction between the electrons and the sample surface to analyze the composition, morphology and structure of the sample. The scanning electron microscope is a precision scientific instrument that can perform high-resolution observations in the microscopic field. In order to achieve higher resolution, a field emission cathode is usually used as the electron source. The field emission electron gun needs to work under ultra-high vacuum conditions and is usually composed of five electrodes: cathode, grid, extraction electrode, focusing electrode and anode. Its maximum voltage can reach tens of kilovolts, which allows electrons to obtain a certain amount of energy and focus to form an electron beam.

[0003] However, the internal environment of the scanning electron microscope must not only meet strict vacuum conditions, but also achieve high-voltage feedthrough, that is, to ensure that high-voltage electricity can be effectively introduced between the ultra-high vacuum and the atmospheric environment. Therefore, the scanning electron microscope in the prior art usually adopts an integrated potting design, which pots and molds the high-voltage transmission line and the scanning electron microscope shell into an integrated structure to achieve high-voltage feedthrough under ultra-high vacuum conditions. However, after the high-voltage transmission line is potted into one with the shell, the high-voltage transmission line will not be disassembled, resulting in a cable connection line when disassembling and assembling the scanning electron microscope. Not only is it inconvenient to operate and transport, it also increases the complexity of maintenance. Summary of the invention

[0004] In view of this, the present invention provides a high-voltage feedthrough component and a scanning electron microscope having the same, so as to solve the technical problem that the high-voltage microscope of the scanning electron microscope in the prior art cannot be disassembled.

[0005] In a first aspect, the present invention provides a high-voltage feedthrough assembly suitable for sealing and mounting on a scanning electron microscope, the high-voltage feedthrough assembly comprising:

[0006] A through-tube, one end of which is provided with an indented socket and the other end is closed, and a plurality of conductive electrodes are fixedly mounted on the closed end of the through-tube;

[0007] A conductive cable is inserted and installed in the concave socket, the conductive cable extends along the axial direction of the through-tube and is suitable for extending outside the conductive cable, and the conductive cable is conductively connected to the conductive electrode;

[0008] The connecting piece is fixedly mounted on the outer side wall of the through sleeve, and is suitable for cooperating with a matching piece on a scanning electron microscope to form a vacuum seal.

[0009] When in use, the high-voltage feedthrough assembly is sealed and installed on the scanning electron microscope to pass high voltage electricity into the scanning electron microscope under vacuum sealing conditions. When installed on the scanning electron microscope, one end of the feedthrough sleeve provided with a conductive electrode extends into the electron gun chamber of the scanning electron microscope, and by connecting one end of the conductive cable to the conductive electrode and the other end extending to the outside to connect to the power supply, the conductive electrode is used to provide high voltage electricity to the electron gun in the electron gun chamber. The conductive cable and the feedthrough sleeve are sealed by potting and the like, and then the connector is used to vacuum seal with the matching piece on the scanning electron microscope, so as to achieve vacuum sealing of the electron gun chamber. In the high-voltage feedthrough assembly, the feedthrough sleeve, the conductive cable, the conductive electrode and the connector are matched to ensure that the high-voltage feedthrough assembly is sealed with the electron gun chamber while providing high voltage power supply to the inside of the electron gun chamber. When the scanning electron microscope is maintained and carried, the connector and the matching piece are separated from each other, and the high-voltage feedthrough assembly can be removed from the electron gun chamber, and then the conductive cable used for power supply is separated from the electron gun chamber, so that the electron gun chamber and the conductive cable are separately carried and maintained.

[0010] In an optional embodiment, a connecting ring is fixedly installed at one end of the through-tube near the outlet end of the inner concave socket, and the connecting ring is sleeved outside the conductive cable, and the axis of the connecting ring coincides with the axis of the through-tube. The connecting ring is used to limit the extension direction of the conductive cable and prevent the potting and sealing effect between the conductive cable and the through-tube from failing due to bending of the conductive cable.

[0011] In an optional implementation, the connection ring is fixedly connected to the conductive cable to prevent the conductive cable from driving the conductive electrode to move during movement, thereby ensuring the stability of the conductive connection between the conductive electrode and the electron gun body in the electron gun chamber.

[0012] In an optional embodiment, a plurality of conductive electrodes are arranged at intervals in a circumferential direction. The thermal field emission electron gun of a field emission electron microscope usually comprises five electrodes: a cathode, a grid, an extraction electrode, a focusing electrode and an anode. Among them, the anode is grounded, and the cathode needs to be connected to two electrodes to ensure power. The voltage between the five electrodes needs to be strictly controlled, and the distance between the electrodes should be considered to avoid discharge. Therefore, a plurality of conductive electrodes are arranged in a circumferential direction, and the spacing between adjacent conductive electrodes is ensured to be above the safe spacing, so as to ensure electrical safety. Preferably, the centers of the five conductive electrodes are evenly arranged along the same circumference.

[0013] In an optional embodiment, the conductive electrode is cylindrical, and the end of the conductive electrode is provided with rounded corners. The conductive electrode is designed to be rounded to avoid sharp edges and ensure that its surface roughness meets good standards, which can avoid the formation of tip discharge on the conductive electrode and further reduce the risk of discharge.

[0014] In an optional embodiment, the through sleeve is a ceramic part, the connecting part is a metal part, and the through sleeve and the connecting part are connected by transition metal welding. Due to the large difference in thermal expansion coefficients between the ceramic part and the metal part, transition metal is selected as the connecting material to effectively relieve thermal stress and improve the reliability of the connection between the two.

[0015] In an optional embodiment, a limiting step is provided at the open end of the through-sleeve, and a matching step is provided on the conductive cable, and the matching step abuts against the limiting step to limit the length of the conductive cable entering the through-sleeve, thereby ensuring that the length of the conductive cable in the through-sleeve matches the length of the through-sleeve, avoiding internal stress of the conductive cable in the through-sleeve, and ensuring the stability of the seal between the through-sleeve and the conductive cable.

[0016] In a second aspect, the present invention further provides a scanning electron microscope having the high voltage feedthrough assembly of the present invention. Since the scanning electron microscope includes the high voltage feedthrough assembly, it has the same effect as the high voltage feedthrough assembly, which will not be described in detail here.

[0017] In an optional embodiment, the electron gun chamber is further included, on which a mounting sleeve is provided, a through sleeve is coaxially installed in the mounting sleeve, the through sleeve is sealed and matched with the mounting sleeve, and one end of the through sleeve provided with a conductive electrode extends into the electron gun chamber. The through sleeve is installed by providing the mounting sleeve, the matching installation length of the through sleeve when installed on the electron gun chamber is extended, and the sealing stability of the through sleeve installed on the electron gun chamber is improved.

[0018] In an optional embodiment, a matching piece is fixedly mounted outside the installation sleeve, and the matching piece is connected to the connecting piece in a vacuum-tight manner. By installing the matching piece on the installation sleeve, the connecting piece and the matching piece are sealed and matched on the installation sleeve, the connection length of the through-sleeve and the electron gun chamber is extended, and the sealing stability between the through-sleeve and the electron gun chamber is increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A schematic structural diagram of the high-voltage feedthrough assembly and the electron gun chamber provided in an embodiment of the present invention being installed in coordination.

[0021] Figure 2A schematic diagram of the end structure of a high-voltage feed-through assembly provided in an embodiment of the present invention.

[0022] Figure 3 for Figure 2 Cross-sectional view along the AA direction.

[0023] Explanation of the reference numerals: 1. Through-tube; 2. Conductive cable; 3. Conductive electrode; 4. Connector; 5. Connecting ring; 6. Electron gun chamber; 7. Mounting tube; 8. Matching part; 9. Transition metal. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0025] Combine the following Figures 1 to 3 , describing an embodiment of the present invention.

[0026] According to an embodiment of the present invention, on one hand, a high-voltage feedthrough assembly is provided, which is suitable for being detachably mounted on a scanning electron microscope. The high-voltage feedthrough assembly includes a feedthrough sleeve 1, a conductive cable 2 and a connector 4.

[0027] The high-voltage feedthrough assembly is installed on the scanning electron microscope to realize the high-voltage electrical access of the scanning electron microscope in a vacuum-sealed environment. The high-voltage feedthrough assembly includes a feedthrough sleeve 1 with a concave socket at one end and a closed end at the other end, and a plurality of conductive electrodes 3 are fixedly installed at the closed end of the feedthrough sleeve 1. The conductive cable 2 is plugged and installed inside the concave socket of the feedthrough sleeve 1, and the conductive cable 2 extends along the axial direction of the feedthrough sleeve 1. One end of the conductive cable 2 is conductively connected to the conductive electrode 3, and the other end extends to the outside of the feedthrough sleeve 1 and is conductively connected to the power supply. The conductive cable 2 is sealed with the open end of the feedthrough sleeve 1. A knife-edge flange as a connector 4 is fixedly installed on the outer wall of the feedthrough sleeve 1. The connector 4 is used to tightly cooperate with another knife-edge flange as a mating part 8 on the scanning electron microscope to achieve vacuum sealing.

[0028] When the high-voltage feedthrough assembly is installed on the scanning electron microscope, one end of the feedthrough sleeve 1 with the conductive electrode 3 extends into the electron gun chamber 6. One end of the conductive cable 2 is connected to the conductive electrode 3, and the other end is extended to the outside to be connected to the power supply, so as to provide the required high voltage electricity to the electron gun in the electron gun chamber 6 through the conductive electrode 3. In order to ensure the sealing performance, the conductive cable 2 and the feedthrough sleeve 1 are sealed by means such as potting. At the same time, the connector 4 is used to perform vacuum sealing with the matching part 8 of the scanning electron microscope to ensure that the vacuum environment of the electron gun chamber 6 is not affected. The high-voltage feedthrough assembly ensures the sealing cooperation with the electron gun chamber 6 through the synergistic effect of the feedthrough sleeve 1, the conductive cable 2, the conductive electrode 3 and the connector 4, and also realizes the provision of stable high-voltage power supply to the inside of the electron gun chamber 6. When the scanning electron microscope needs to be maintained or transported, the high-voltage feedthrough assembly can be easily removed from the electron gun chamber 6 by simply separating the connector 4 from the matching member 8, thereby separating the power supply conductive cable 2 from the electron gun chamber 6, making it convenient to transport and maintain the electron gun chamber 6 and the conductive cable 2, respectively. On the premise of ensuring the stability and reliability of the scanning electron microscope in terms of high-voltage power supply and vacuum sealing, the convenience of transporting and maintaining the scanning electron microscope is improved.

[0029] In order to prevent leakage or short circuit of the conductive cable 2 or the conductive electrode 3 during operation, and to ensure that the through-tube 1 is fixedly welded to the metal part, the through-tube 1 is set as a ceramic part in this embodiment. In order to reduce the degassing rate of the material, a glaze layer is coated on the inside of the through-tube 1 by a glazing process to ensure the vacuum maintenance performance of the through-tube 1. The conductive electrode 3 is a metal electrode, and the conductive electrode 3 is fixedly connected to the through-tube 1 by transition metal welding.

[0030] In one embodiment, a connecting ring 5 is fixedly provided at one end of the inner recessed socket outlet end of the through-sleeve 1. The connecting ring 5 is tightly wrapped around the outer periphery of the conductive cable 2, and the axis of the connecting ring 5 coincides with the axis of the through-sleeve 1 to ensure that the connecting ring 5 and the through-sleeve 1 are coaxially arranged, so that the connecting ring 5 can effectively limit the extension direction of the conductive cable 2, avoid the disordered movement of the conductive cable 2 in the through-sleeve 1, and enhance the structural integrity between the conductive cable 2 and the through-sleeve 1. More importantly, by providing the connecting ring 5, the weakening or failure of the potting sealing effect between the conductive cable 2 and the through-sleeve 1 caused by improper bending of the conductive cable 2 can be effectively prevented, and the safety performance and long-term reliability of the electrical system composed of the conductive cable 2 and the through-sleeve 1 can be maintained. As an alternative embodiment, a layer of elastic buffer material, such as a silicone sleeve, can be added between the connecting ring 5 and the conductive cable 2 to further enhance the protection of the conductive cable 2 and provide a better sealing effect.

[0031] In one embodiment, the connection ring 5 is fixedly connected to the conductive cable 2 to prevent the conductive electrode 3 from being displaced when the conductive cable 2 moves or is subjected to external force, thereby ensuring that the conductive electrode 3 can maintain a stable and reliable conductive connection with the electron gun body in the electron gun chamber 6. The working stability of the electron gun body is improved, and the risk of electron gun performance degradation or failure due to poor connection is reduced. Specifically, the connection ring 5 and the conductive cable 2 can be tightly fixed by welding, mechanical locking, or bonding with an adhesive to ensure the stable performance of the high-voltage feed-through assembly.

[0032] In one embodiment, a plurality of conductive electrodes 3 are arranged in a circumferential direction, and a thermal field emission electron gun in a field emission electron microscope generally includes five key electrodes, namely a cathode, a grid, an extraction electrode, a focusing electrode and an anode. The anode serves as a ground electrode to ensure the effective extraction of current, and the cathode is connected to two electrodes to maintain the power-on state. In order to ensure the efficient operation of the electron gun and the stability of the electrical performance, the voltage regulation between the five electrodes needs to be strictly controlled. At the same time, the distance between adjacent electrodes also needs to strictly comply with safety standards to avoid discharge. To this end, each conductive electrode 3 is evenly arranged along the circumference, and the distance between adjacent electrodes is kept greater than the safety distance. As an alternative embodiment, the centers of the five electrodes are located on the same circumference but are unevenly distributed. By fine-tuning the electrode positions, a more compact and efficient electric field distribution is achieved, thereby further improving the overall performance and stability of the electron gun while ensuring electrical safety.

[0033] In one embodiment, the conductive electrode 3 is set to be cylindrical, and its end is chamfered to eliminate the edges and corners of the conductive electrode 3, while ensuring that the surface roughness of the conductive electrode 3 reaches a good standard. By adopting a rounded shape design, it is possible to effectively prevent the formation of tip discharge on the surface of the conductive electrode 3, thereby reducing the risk of discharge. As an alternative embodiment, the conductive electrode 3 can also be a long strip structure such as a truncated cone, a prism, or a prism, and the edges and corners of the conductive electrode 3 are chamfered.

[0034] In one embodiment, the through sleeve 1 is a ceramic part, the connecting part 4 is a metal part, and the through sleeve 1 and the connecting part 4 are connected by welding with a transition metal 9. Due to the large difference in thermal expansion coefficients between the ceramic part and the metal part, the transition metal 9 is selected as the connecting material to effectively relieve thermal stress and improve the reliability of the connection between the two.

[0035] In one embodiment, a limiting step is provided at the open end of the through-sleeve 1, and a matching step is provided on the conductive cable 2, and the matching step abuts against the limiting step to limit the length of the conductive cable 2 entering the through-sleeve 1, thereby ensuring that the length of the conductive cable 2 in the through-sleeve 1 matches the length of the through-sleeve 1, avoiding the conductive cable 2 from generating internal stress in the through-sleeve 1, and ensuring the stability of the seal between the through-sleeve 1 and the conductive cable 2.

[0036] The high-voltage feedthrough assembly provided in this embodiment can meet the high-voltage feedthrough requirements of the field emission electron gun in an ultra-high vacuum environment, and has good stability and is convenient for transportation and maintenance. The following requirements are considered in the design of the high-voltage feedthrough assembly: it is necessary to realize the power-on of the five electrodes, while ensuring the safe distance between the five electrodes, and ensuring the safety between the five power posts and the zero-potential shell; in order to obtain ultra-high vacuum, a baking operation is required, and the temperature is generally 200°C. The high-voltage feedthrough assembly fully considers the high-temperature resistance in material selection and processing, and can withstand a high temperature of 250°C; the electron gun needs to work in an ultra-high vacuum environment, and the high-voltage feedthrough assembly needs to have a certain sealing performance, and the leakage rate meets the use conditions of ultra-high vacuum; it is easy to repair and transport, and the high-voltage feedthrough assembly can be plugged and unplugged, which is convenient for maintenance and transportation. The high-voltage feedthrough assembly can not only achieve vacuum sealing, but also has the characteristics of high pressure resistance and high temperature resistance. The centers of the five conductive electrodes 3 in the form of power posts are distributed in a circular form on the porcelain bottle as the feedthrough sleeve 1. After calculation, it is ensured that the conductive electrodes 3 and the outer wall of the feedthrough sleeve 1 maintain a safe distance so that they can be used stably under high voltage. The through-tube 1 is connected to the knife-edge flange as the connector 4 by welding to ensure good sealing. During use, the electron gun is located inside the electron gun chamber 6. When the scanning electron microscope is working, the electron gun chamber 6 maintains an ultra-high vacuum environment. The high-voltage through-tube assembly is connected to another knife-edge flange as a matching part 8 welded on the electron gun chamber 6 through the knife-edge flange as the connector 4. The cathode, grid, suction electrode and focusing electrode of the electron gun are connected to the electron gun inside the vacuum electron gun chamber 6 through a dedicated wire in the vacuum, and the outer side of the through-tube 1 is connected to the high-voltage power supply through the conductive cable 2 to realize the supply of power.

[0037] According to an embodiment of the present invention, on the other hand, a scanning electron microscope is provided, which has the high-voltage feedthrough assembly of the present invention. The high-voltage feedthrough assembly is used to be detachably mounted on a scanning electron microscope so as to pass high voltage electricity into the scanning electron microscope under vacuum sealing conditions. When installed on the scanning electron microscope, one end of the feedthrough sleeve 1 provided with a conductive electrode 3 extends into the electron gun chamber 6 of the scanning electron microscope, and by connecting one end of the conductive cable 2 to the conductive electrode 3 and the other end extending to the outside to connect to the power supply, the conductive electrode 3 is used to provide high voltage electricity to the electron gun in the electron gun chamber 6. The conductive cable 2 is sealed between the feedthrough sleeve 1 by potting or the like, and then the connector 4 is used to vacuum seal with the matching piece 8 on the scanning electron microscope, thereby realizing vacuum sealing of the electron gun chamber 6. In the high-voltage feedthrough assembly, the feedthrough sleeve 1, the conductive cable 2, the conductive electrode 3 and the connector 4 are matched to ensure that the high-voltage feedthrough assembly provides high voltage power supply to the inside of the electron gun chamber 6 while sealing with the electron gun chamber 6. When the scanning electron microscope is being maintained and transported, the connector 4 and the matching member 8 are separated from each other, the high-voltage feedthrough assembly can be removed from the electron gun chamber 6, and the conductive cable 2 used for power supply is separated from the electron gun chamber 6, so that the electron gun chamber 6 and the conductive cable 2 can be transported and maintained separately.

[0038] In one embodiment, an electron gun chamber 6 is provided in a scanning electron microscope, a mounting sleeve 7 is provided on the electron gun chamber 6, and a through sleeve 1 is coaxially installed inside the mounting sleeve 7, wherein the through sleeve 1 is sealed with the mounting sleeve 7, and one end of the through sleeve 1 provided with a conductive electrode 3 extends into the electron gun chamber 6. By introducing the mounting sleeve 7 as an intermediary, the installation length of the matching structure when the through sleeve 1 is installed in the electron gun chamber 6 is extended. The installation stability between the through sleeve 1 and the electron gun chamber 6 is enhanced, and the reliability of the sealing match between the two is improved. In some other embodiments, in order to further improve the sealing effect of the matching connection between the through sleeve 1 and the mounting sleeve 7, on the basis of maintaining the coaxial installation of the through sleeve 1 and the mounting sleeve 7, an elastic sealing ring is added between the through sleeve 1 and the mounting sleeve 7 to ensure that stable sealing performance can be maintained under various working conditions.

[0039] In one embodiment, another knife-edge flange as a fitting 8 is fixedly mounted outside the mounting sleeve 7, and a sealing connection is achieved between the two knife-edge flanges of the fitting 8 and the connecting member 4. By fixing the fitting 8 on the mounting sleeve 7, the connecting member 4 and the fitting 8 form a tight and reliable sealing fit on the mounting sleeve 7, thereby enhancing the sealing stability between the two.

[0040] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A high voltage feed-through assembly, characterized in that: Suitable for sealed mounting on a scanning electron microscope, the high voltage feedthrough assembly comprises: A through-tube (1) having a concave socket at one end and a closed end, wherein a plurality of conductive electrodes (3) are fixedly mounted at the closed end of the through-tube (1); A conductive cable (2) is inserted and installed in the recessed socket, the conductive cable (2) extends along the axial direction of the through-tube (1) and is suitable for extending outside the conductive cable (2), and the conductive cable (2) is conductively connected to the conductive electrode (3); A connecting piece (4) is fixedly mounted on the outer wall of the through-tube (1), and the connecting piece (4) is suitable for cooperating with a matching piece (8) on the scanning electron microscope to form a vacuum seal.

2. The high voltage feed-through assembly according to claim 1, characterized in that: A connecting ring (5) is fixedly installed at one end of the through-tube (1) close to the outlet end of the inner concave socket, and the connecting ring (5) is sleeved outside the conductive cable (2), and the axis of the connecting ring (5) coincides with the axis of the through-tube (1).

3. The high voltage feed-through assembly according to claim 2, characterized in that: The connecting ring (5) is fixedly connected to the conductive cable (2).

4. The high voltage feed-through assembly according to any one of claims 1 to 3, characterized in that: The plurality of conductive electrodes (3) are arranged at intervals along the circumferential direction.

5. The high voltage feed-through assembly according to any one of claims 1 to 3, characterized in that: The conductive electrode (3) is cylindrical, and the end of the conductive electrode (3) is provided with a rounded corner.

6. The high voltage feed-through assembly according to any one of claims 1 to 3, characterized in that: The through-tube (1) is a ceramic part, the connecting part (4) is a metal part, and the through-tube (1) and the connecting part (4) are connected by welding using a transition metal (9).

7. The high voltage feed-through assembly according to any one of claims 1 to 3, characterized in that: The open end of the through-tube (1) is provided with a limiting step, and the conductive cable (2) is provided with a matching step, the matching step being in abutment with the limiting step.

8. A scanning electron microscope, characterized in that A high voltage feed-through assembly according to any one of claims 1 to 7.

9. The scanning electron microscope according to claim 8, characterized in that It also comprises an electron gun chamber (6) on which a mounting sleeve (7) is arranged. A through-sleeve (1) is coaxially mounted in the mounting sleeve (7). The through-sleeve (1) and the mounting sleeve (7) are sealed and matched. One end of the through-sleeve (1) provided with a conductive electrode (3) extends into the electron gun chamber (6).

10. The scanning electron microscope according to claim 9, characterized in that A matching piece (8) is fixedly mounted outside the installation sleeve (7), and the matching piece (8) is vacuum-tightly connected to the connecting piece (4).

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