Built-in detector probe and scanning electron microscope

Abstract

The invention relates to the technical field of electron microscopy, and discloses a built-in detector probe and a scanning electron microscope. The scintillation crystal is connected with one end of the electron beam conduit; the axis of the light guide column is perpendicular to the axis of the electron beam conduit, one end of the light guide column is provided with a parabolic cylinder with an opening facing the other end of the light guide column, and the parabolic cylinder is provided with a reflecting film; the electron beam conduit penetrates through two opposite sides of the light guide column and passes through the parabolic cylinder; the scintillation crystal is also connected with the light guide column; and the photomultiplier is connected with one end, far away from the parabolic cylinder, of the light guide column. According to the invention, the parabolic cylinder is arranged on the light guide column and the reflecting film is arranged on the parabolic cylinder, so that a similarly vertical secondary electronic signal can be collimated into a horizontal optical signal, a large number of optical signals are captured and transmitted to the photomultiplier, and the capture efficiency of photons and the signal-to-noise ratio of an image can be remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of electron microscopy, specifically to a built-in detector probe and a scanning electron microscope. Background Technology

[0002] Scanning electron microscopy (SEM) is an indispensable characterization tool in modern nanotechnology and materials science research. Its working principle involves using a finely focused electron beam to perform a grating-like scan on the sample surface, forming an image by detecting the physical signals generated by the interaction between the electron beam and the sample (such as secondary electrons and backscattered electrons). Among these, the secondary electron signal is extremely sensitive to the sample surface morphology, and its imaging resolution can reach the nanometer scale, making it crucial for observing the details of microstructures.

[0003] In scanning electron microscopes (SEMs), secondary electron detectors are mainly classified into two categories based on their installation location: side-mounted detectors and in-lens detectors. Side-mounted detectors are installed on the side wall of the sample chamber. While simple in structure, their collection efficiency for low-energy secondary electrons is low due to their distance from the sample and limited solid angle, resulting in limited image signal-to-noise ratio and resolution. In contrast, in-lens detectors are integrated inside or above the objective lens. Utilizing the strong magnetic field of the objective lens, they can efficiently collect and guide low-energy secondary electrons, thereby obtaining images with higher resolution, richer surface details, and better signal-to-noise ratio. They have become a core component of high-performance SEMs.

[0004] However, existing in-lens detectors still have inherent defects in the physical path of signal conversion and transmission. Current mainstream designs mostly employ a layout where the electron beam, scintillator, and light guide pillar axes are parallel or nearly parallel. For example, existing technology discloses a secondary electron detector for scanning electron microscopes, which includes: a cylinder assembly, a grid assembly, a high-voltage cylinder, a light guide pillar, a scintillator, a housing, a photomultiplier mirror, and a power supply. The high-voltage cylinder includes an upper high-voltage cylinder section and a lower high-voltage cylinder section connected in the axial direction of the cylinder assembly. In this configuration, the fluorescence generated by the electron beam bombarding the scintillator is emitted in all directions (isotropic). The light guide pillar located to the side or rear can only capture photons within a limited solid angle, causing most photons to be scattered or absorbed due to the excessively large angle between their propagation direction and the light guide pillar axis, resulting in a low image signal-to-noise ratio. Summary of the Invention

[0005] To address the problem of low photon capture efficiency leading to low image signal-to-noise ratio in the prior art, this invention provides a built-in detector probe and scanning electron microscope that can collimate the optical signal into a signal transmitted along the axis of the light guide post, which is beneficial to improving photon capture efficiency and image signal-to-noise ratio.

[0006] In a first aspect, the present invention provides a built-in detector probe, comprising: an electron beam guide; a scintillation crystal connected to one end of the electron beam guide; a light guide post, the axis of which is perpendicular to the axis of the electron beam guide, one end of which has a parabolic cylindrical surface with its opening facing the other end, the parabolic cylindrical surface being a cylindrical surface formed by translating a parabola, and a reflective film provided on the parabolic cylindrical surface; the electron beam guide passing through opposite sides of the light guide post and passing through the parabolic cylindrical surface; the scintillation crystal also being connected to the light guide post; and a photomultiplier connected to the end of the light guide post away from the parabolic cylindrical surface.

[0007] The probe described above can be inserted horizontally into the tube of a scanning electron microscope. An electron beam sweeps across the sample placed below the scintillation crystal through an electron beam guide, exciting secondary electrons. These electrons are strongly attracted by the positive bias voltage at the port of the electron beam guide and bombard the scintillation crystal. The scintillation crystal emits isotropic light after being excited. This light is reflected by a reflective film of a specific shape and converted into collimated light parallel to the axis of the light guide post. Finally, it is converted into a measurable electrical signal output by a photomultiplier.

[0008] Preferably, the scintillation crystal is circular, the electron beam guide passes through the midpoint of the focal line of the parabolic cylinder, and one end of the electron beam guide is connected to the center of the scintillation crystal; the parabolic cylinder satisfies the following functional equation: y = ; In the formula, x and y represent the horizontal and vertical coordinates of any point on the parabolic cylinder in the coordinate system, respectively, and p represents the diameter of the scintillation crystal, all in mm. The coordinate system has its origin at the end of the parabolic cylinder furthest from the photomultiplier, with the x-axis parallel to the axis of the light guide column, pointing positively towards the photomultiplier; and the y-axis perpendicular to the x-axis and passing through the origin. It can be understood that the focal line of the parabolic cylinder is a straight line parallel to the generatrix of the parabolic cylinder and passing through the focal point of all the parabolic sections. Photons emitted from the midpoint of the focal line of the parabolic cylinder can strike the reflective film in large numbers, and after passing through the reflective film, most can be converted into horizontal light signals, and a small portion into near-horizontal light signals, which can ultimately be largely received by the photomultiplier. The electron beam guide passing through the midpoint of the focal line of the parabolic cylinder allows secondary electrons to concentrate at the midpoint, which is beneficial for improving light capture efficiency. Furthermore, the parabolic cylinder of the present invention is formed by half of a parabola because secondary electrons move upward. Only the part of the light emitted by the scintillator that is directed upward toward the parabolic cylinder is the useful signal that needs to be collected and collimated, while photons emitted downward will be lost. Even if the other half of the parabola is set to form a surface, it will not make a significant difference in improving the light capture efficiency.

[0009] Preferably, the device further includes a probe housing with a protective cavity. The electron beam guide tube is connected to the probe housing, and both the scintillation crystal and the parabolic cylinder are located within the protective cavity. Since the scintillation crystal and parabolic cylinder are relatively fragile, the probe housing prevents accidental damage to them by hands or tools, and also prevents dust and other contaminants from adhering to the scintillation crystal and parabolic cylinder, thus avoiding interference with light absorption and scattering.

[0010] Preferably, a grounding spring is provided at the end of the probe housing furthest from the photomultiplier. The grounding spring can press against the inner wall of the scanning electron microscope barrel, guiding the diverging electrons through the barrel to the ground, preventing charge accumulation from affecting the stability of the electron beam. Furthermore, the grounding spring provides some support and cushioning for the entire detector probe, preventing external vibrations from causing the probe to sway up and down.

[0011] Preferably, the probe housing includes: an upper protective cover; and a lower protective cover, the lower protective cover being detachably connected to the upper protective cover, and the two together forming the protective cavity; a through cavity is provided on the side of the lower protective cover away from the upper protective cover, through which the side of the scintillation crystal away from the upper protective cover is exposed. Dividing the probe housing into a detachable upper protective cover and a lower protective cover facilitates the disassembly and assembly of the probe housing, enabling the replacement and maintenance of internal components. The connection method between the upper and lower protective covers can be a snap-fit ​​connection, a threaded connection, or a bolted connection.

[0012] Preferably, the system further includes a mounting ring, which is sleeved on the outside of the light guide post and located between the probe housing and the photomultiplier. The mounting ring is threaded with multiple first bolts for connection to the electron microscope barrel. The mounting ring and the first bolts thereon are the main connection points between the entire detector probe and the scanning electron microscope barrel, allowing the entire detector probe to be securely mounted on the scanning electron microscope barrel.

[0013] Preferably, the system further includes a pressure ring, the outer diameter of which is smaller than that of the mounting ring and is fitted over the outside of the light guide post. One side of the pressure ring has a first groove. A limiting ring is provided on the outside of the light guide post, located within the first groove, with one side of the limiting ring flush with one side of the pressure ring. One side of the mounting ring has a second groove, the pressure ring is located within the second groove, and the other side of the pressure ring is flush with the side of the mounting ring with the second groove. The pressure ring and the mounting ring are connected by a second bolt. The limiting ring serves as a positioning reference for the mounting ring, facilitating accurate installation by the operator. This detachable combination of the mounting ring, pressure ring, and limiting ring results in a compact structure and facilitates the replacement and maintenance of the light guide post.

[0014] Preferably, the system further includes: a first sealing ring, which is fitted over the outside of the light guide post and connected to the side of the mounting ring away from the photomultiplier; and a second sealing ring, which is fitted over the outside of the light guide post and located between the mounting ring and the limiting ring, abutting against both. The first sealing ring, located on the mating surface between the mounting ring and the scanning electron microscope barrel, prevents atmospheric leakage into the vacuum environment of the microscope barrel, ensuring normal electron beam transmission and preventing sample contamination. The second sealing ring, located between the mounting ring and the limiting ring, further improves the airtightness of the microscope barrel.

[0015] Preferably, the scintillation crystal and the light guide post are bonded together with optical adhesive, which helps to improve the light transmission efficiency.

[0016] Secondly, the present invention also provides a scanning electron microscope (SEM), comprising: an optical tube for generating an electron beam to scan a sample; an objective lens for focusing the electron beam, the objective lens being disposed below the optical tube; a sample chamber for holding the sample, the sample chamber being disposed below the objective lens; and the aforementioned built-in detector probe, the built-in detector probe being installed inside the optical tube, the electron beam emitted by the optical tube passing through the electron beam guide. Except for the built-in detector probe, the other structures of the SEM are prior art, therefore their specific structures and working principles will not be described in detail.

[0017] The beneficial effects of this invention are: 1. By creating a parabolic cylindrical surface on the light guide and setting a reflective film on the parabolic cylindrical surface, a similar vertical secondary electron signal can be collimated into a horizontal light signal, thereby capturing and transmitting a large amount of light signal to the photomultiplier, which can significantly improve the photon capture efficiency and image signal-to-noise ratio.

[0018] 2. Adding a probe housing to the front end of the light guide post and installing a grounding spring on the housing can prevent charge accumulation and vibration effects. Attached Figure Description

[0019] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a built-in detector probe according to an embodiment of the present invention; Figure 2This is a schematic diagram illustrating the working principle of a built-in detector probe according to an embodiment of the present invention; the dashed lines in the figure represent the transmission path of the electron beam, and the solid lines represent the transmission path of secondary electrons or photons. Figure 3 This is a schematic diagram of the probe housing. Figure 4 This is a cross-sectional view of a built-in detector probe according to an embodiment of the present invention; Figure 5 This is a schematic diagram of a scanning electron microscope according to an embodiment of the present invention; the thick solid line in the figure represents the transmission path of the electron beam, and the dashed line represents the transmission path of secondary electrons.

[0021] Explanation of reference numerals in the attached figures: 1. Electron beam guide tube; 2. Scintillation crystal; 3. Light guide column; 301. Parabolic cylinder; 302. Limiting ring; 4. Photomultiplier; 5. Probe housing; 501. Upper protective cover; 5011. Protective cavity; 502. Lower protective cover; 5021. Through cavity; 6. Grounding spring; 7. Mounting ring; 701. Second groove; 8. First bolt; 9. Pressure ring; 901. First groove; 10. Second bolt; 11. First sealing ring; 12. Second sealing ring; 13. Optical tube; 14. Objective lens; 15. Sample chamber. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The following is combined with Figures 1 to 5 The following describes embodiments of the present invention.

[0024] According to an embodiment of the present invention, in one aspect, a built-in detector probe is provided, combined with Figures 1 to 4As shown, it includes: an electron beam guide 1; a scintillation crystal 2 connected to one end of the electron beam guide 1, the upper surface of the scintillation crystal 2 being coated with an aluminum film; a light guide column 3 made of plexiglass, the axis of the light guide column 3 being perpendicular to the axis of the electron beam guide 1, one end of the light guide column 3 having a parabolic cylindrical surface 301 with an opening facing the other end, the parabolic cylindrical surface 301 being a cylindrical surface formed by translating a parabola, a reflective film being provided on the parabolic cylindrical surface 301; the electron beam guide 1 passing through the opposite sides of the light guide column 3 and passing through the parabolic cylindrical surface 301; the scintillation crystal 2 also being connected to the light guide column 3; and a photomultiplier 4 connected to the end of the light guide column 3 away from the parabolic cylindrical surface 301.

[0025] The probe described above can be inserted horizontally into the tube of a scanning electron microscope. An electron beam sweeps through the electron beam guide 1 across the sample placed below the scintillation crystal 2, exciting secondary electrons. These electrons, under the strong attraction of a positive bias voltage at the port of the electron beam guide 1, advance in a spiral shape and bombard the scintillation crystal 2. The scintillation crystal 2, after being excited, emits isotropic light. This light is reflected by a reflective film of a specific shape and converted into collimated light parallel to the axis of the light guide post. Finally, it is converted into a measurable electrical signal output by the photomultiplier 4. By creating a parabolic cylindrical surface 301 on the light guide post 3 and placing a reflective film on the parabolic cylindrical surface 301, the similarly vertical secondary electron signal can be collimated into a horizontal light signal, thereby capturing and transmitting a large amount of light signal to the photomultiplier 4, significantly improving the photon capture efficiency and image signal-to-noise ratio.

[0026] Specifically, the scintillation crystal 2 is circular, and the electron beam guide 1 passes through the midpoint of the focal line of the parabolic cylinder 301, with one end of the electron beam guide 1 connected to the center of the scintillation crystal 2; the parabolic cylinder 301 satisfies the following functional equation: y = ; In the formula, x and y represent the horizontal and vertical coordinates of any point on the parabolic cylinder 301 in the coordinate system, respectively, and p represents the diameter of the scintillation crystal 2, all in mm. The coordinate system has its origin at the end of the parabolic cylinder 301 furthest from the photomultiplier 4, with the x-axis parallel to the axis of the light guide post 3, pointing positively towards the photomultiplier 4; and the y-axis perpendicular to the x-axis and passing through the origin. It can be understood that the focal line of the parabolic cylinder 301 is a straight line parallel to the generatrix of the parabolic cylinder 301 and passing through the focus of all the parabolic sections. Photons emitted from the midpoint of the focal line of the parabolic cylinder 301 can strike the reflective film in large quantities, and after passing through the reflective film, most can be converted into horizontal light signals, and a small portion into near-horizontal light signals, which can ultimately be largely received by the photomultiplier 4. The electron beam guide 1 passes through the midpoint of the focal line of the parabolic cylinder 301, which allows secondary electrons to be concentrated at the midpoint of the focal line of the parabolic cylinder 301, thus improving the light capture efficiency. Furthermore, the parabolic cylinder 301 of this invention is formed by half of a parabola because secondary electrons move upwards. Only the portion of the light emitted by the scintillator that strikes the parabolic cylinder 301 upwards is the useful signal that needs to be collected and collimated, while photons emitted downwards are lost. Therefore, even if the other half of the parabola is used to form a surface, improving the light capture efficiency would not be significantly meaningful.

[0027] Furthermore, the device also includes a probe housing 5, which has a protective cavity 5011. The electron beam guide tube 1 is inserted into the probe housing 5, and the scintillation crystal 2 and the parabolic cylinder 301 are both located within the protective cavity 5011. The scintillation crystal 2 and the parabolic cylinder 301 are relatively fragile. The probe housing 5 can prevent accidental damage to the scintillation crystal 2 and the parabolic cylinder 301 by human hands or tools, and at the same time prevent dust and other contaminants from adhering to the scintillation crystal 2 and the parabolic surface, thus avoiding affecting the absorption and scattering of light.

[0028] Furthermore, a grounding spring 6 is provided at the end of the probe housing 5 furthest from the photomultiplier 4. Both the grounding spring 6 and the probe housing 5 are made of pure copper. The grounding spring 6 can press against the inner wall of the scanning electron microscope tube, guiding the diverging electrons through the tube to the ground, preventing charge accumulation from affecting the stability of the electron beam. Moreover, the grounding spring 6 can provide some support and buffer for the entire detector probe, preventing external vibrations from causing the probe to sway up and down.

[0029] Furthermore, the probe housing 5 includes: an upper protective cover 501; and a lower protective cover 502, which is detachably connected to the upper protective cover 501, and the two together form a protective cavity 5011. A through cavity 5021 is provided on the side of the lower protective cover 502 away from the upper protective cover 501. The through cavity 5021 is circular and has the same diameter as the scintillation crystal 2. The side of the scintillation crystal 2 away from the upper protective cover 501 is exposed through the through cavity 5021. Dividing the probe housing 5 into a detachable upper protective cover 501 and a lower protective cover 502 facilitates the disassembly and assembly of the probe housing 5, enabling the replacement and maintenance of internal components. The connection between the upper protective cover 501 and the lower protective cover 502 can be a snap-fit, a threaded connection, or a bolted connection. In this embodiment, the upper protective cover 501 and the lower protective cover 502 are connected by bolts.

[0030] Furthermore, it also includes a mounting ring 7, which is sleeved on the outside of the light guide post 3 and located between the probe housing 5 and the photomultiplier 4. The mounting ring 7 is threaded with multiple first bolts 8 for connecting to the electron microscope barrel. The mounting ring 7 and the first bolts 8 thereon are the main connection points between the entire detector probe and the scanning electron microscope barrel. The mounting ring 7 can securely mount the entire detector probe onto the scanning electron microscope barrel.

[0031] Furthermore, it also includes a pressure ring 9, the outer diameter of which is smaller than that of the mounting ring 7, and it is fitted over the outside of the light guide post 3. A first groove 901 is provided on one side of the pressure ring 9. A limiting ring 302 is provided on the outside of the light guide post 3, the limiting ring 302 being located within the first groove 901, and one side of the limiting ring 302 being flush with one side of the pressure ring 9. A second groove 701 is provided on one side of the mounting ring 7, the pressure ring 9 being located within the second groove 701, and the other side of the pressure ring 9 being flush with the side of the mounting ring 7 with the second groove 701. The pressure ring 9 and the mounting ring 7 are connected by a second bolt 10. The limiting ring 302 serves as a positioning reference for the mounting ring 7, facilitating the operator to install the mounting ring 7 in the accurate position. This detachable combination of the mounting ring 7, pressure ring 9, and limiting ring 302 results in a compact structure and facilitates the replacement and maintenance of the light guide post 3.

[0032] Furthermore, it also includes: a first sealing ring 11, which is sleeved on the outside of the light guide post 3 and connected to the side of the mounting ring 7 away from the photomultiplier 4; and a second sealing ring 12, which is sleeved on the outside of the light guide post 3 and located between the mounting ring 7 and the limiting ring 302, abutting against both. The first sealing ring 11 is located on the mating surface between the mounting ring 7 and the scanning electron microscope tube, which can prevent atmospheric leakage into the vacuum environment of the electron microscope tube, ensuring normal electron beam transmission and sample protection. The second sealing ring 12 is located between the mounting ring 7 and the limiting ring 302, which helps to further improve the airtightness of the electron microscope tube.

[0033] Furthermore, the scintillation crystal 2 and the light guide post 3 are bonded together with optical adhesive, which helps to improve the light transmission efficiency.

[0034] According to an embodiment of the present invention, in another aspect, a scanning electron microscope is also provided, combined with... Figures 1 to 5 As shown, it includes: an optical tube 13 for generating an electron beam to scan the sample; an objective lens 14 for focusing the electron beam, the objective lens 14 being located below the optical tube 13; a sample chamber 15 for holding the sample, the sample chamber 15 being located below the objective lens 14; and the aforementioned built-in detector probe, which is installed inside the optical tube 13, and the electron beam emitted by the optical tube 13 passes through the electron beam guide tube 1. Except for the built-in detector probe, the other structures of the scanning electron microscope are existing technologies, therefore their specific structures and working principles will not be described in detail.

[0035] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A built-in detector probe, characterized in that, include: Electron beam guide tube (1); A scintillation crystal (2) is connected to one end of the electron beam guide tube (1); A light guide post (3) is provided, the axis of which is perpendicular to the axis of the electron beam guide tube (1). One end of the light guide post (3) is provided with a parabolic cylindrical surface (301) with its opening facing the other end. A reflective film is provided on the parabolic cylindrical surface (301). The electron beam guide tube (1) passes through the opposite sides of the light guide post (3) and passes through the parabolic cylindrical surface (301). The scintillation crystal (2) is also connected to the light guide post (3). A photomultiplier (4) is connected to one end of the light guide column (3) away from the parabolic cylindrical surface (301).

2. The built-in detector probe according to claim 1, characterized in that, The scintillation crystal (2) is circular, and the electron beam guide (1) passes through the midpoint of the focal line of the parabolic cylinder (301), with one end of the electron beam guide (1) connected to the center of the scintillation crystal (2). The parabolic cylinder (301) satisfies the following functional equation: y＝ ； In the formula, x and y represent the horizontal and vertical coordinates of any point on the parabolic cylinder (301) in the coordinate system, respectively, and p represents the diameter of the scintillation crystal (2); wherein the coordinate system takes the end of the parabolic cylinder (301) away from the photomultiplier (4) as the origin, the direction parallel to the axis of the light guide column (3) as the x-axis, and the positive direction points to the photomultiplier (4); and the axis perpendicular to the x-axis and passing through the origin of the coordinate system as the y-axis.

3. The built-in detector probe according to claim 1, characterized in that, It also includes a probe housing (5), which has a protective cavity (5011). The electron beam guide tube (1) is connected to the probe housing (5), and the scintillation crystal (2) and the parabolic cylinder (301) are both located in the protective cavity (5011).

4. The built-in detector probe according to claim 3, characterized in that, A grounding spring (6) is provided at the end of the probe housing (5) away from the photomultiplier (4).

5. A built-in detector probe according to claim 3, characterized in that, The probe housing (5) includes: Upper protective cover (501); The lower protective cover (502) is detachably connected to the upper protective cover (501), and the two together form the protective cavity (5011); a through cavity (5021) is provided on the side of the lower protective cover (502) away from the upper protective cover (501), and the side of the scintillation crystal (2) away from the upper protective cover (501) is exposed to the outside through the through cavity (5021).

6. The built-in detector probe according to claim 3, characterized in that, It also includes a mounting ring (7), which is sleeved on the outside of the light guide post (3) and located between the probe housing (5) and the photomultiplier (4). The mounting ring (7) is threaded with a plurality of first bolts (8) for connecting to the electron microscope barrel.

7. A built-in detector probe according to claim 6, characterized in that, It also includes a pressure ring (9), the outer diameter of which is smaller than that of the mounting ring (7) and is sleeved on the outside of the light guide post (3). A first groove (901) is provided on one side of the pressure ring (9). A limiting ring (302) is provided on the outside of the light guide post (3). The limiting ring (302) is located in the first groove (901) and one side of the limiting ring (302) is flush with one side of the pressure ring (9). A second groove (701) is provided on one side of the mounting ring (7). The pressure ring (9) is located in the second groove (701) and the other side of the pressure ring (9) is flush with the side of the mounting ring (7) where the second groove (701) is opened. The pressure ring (9) and the mounting ring (7) are connected by a second bolt (10).

8. A built-in detector probe according to claim 7, characterized in that, Also includes: The first sealing ring (11) is sleeved on the outside of the light guide post (3) and connected to the side of the mounting ring (7) away from the photomultiplier (4); The second sealing ring (12) is sleeved on the outside of the light guide post (3) and is located between the mounting ring (7) and the limiting ring (302), abutting against both of them.

9. A built-in detector probe according to claim 1, characterized in that, The scintillation crystal (2) and the light guide post (3) are bonded together with optical adhesive.

10. A scanning electron microscope, characterized in that, include: An optical tube (13) is used to generate an electron beam to scan the sample; An objective lens (14) is used to focus the electron beam, and the objective lens (14) is located below the optical tube (13); A sample chamber (15) for holding a sample is located below the objective lens (14); The built-in detector probe as described in any one of claims 1 to 9 is installed inside the optical lens tube (13), and the electron beam emitted by the optical lens tube (13) passes through the electron beam guide tube (1).

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