Clamping device for three-dimensional reconstruction sample rod of transmission electron microscope

Abstract

The invention discloses a clamping device for a three-dimensional reconstruction sample rod of a transmission electron microscope, and belongs to the technical field of electron microscopy. The device comprises a sample rod section, a clamping rod and a protection frame. The near end of the sample rod section is connected with the in-situ mechanical sample rod through a mounting structure, and the far end of the sample rod section is matched with the conical rod of the clamping rod through a conical hole to realize coaxial locking; the clamping rod adopts a split structure to clamp a needle-shaped sample; the protection frame is detachably inserted into the angle slot at the far end of the sample rod section, and a light shielding groove is formed in the front end of the protection frame. According to the device, the front end of an existing sample rod is modified in a modularized mode, so that the whole clamping module is locked again after rotating by a fixed angle relative to an original rod, and rapid switching of a sample in two orthogonal directions is achieved. In combination with an angle measuring table tilting function of the electron microscope, large-angle image sequences in the orthogonal direction are collected twice, and quasi 360-degree three-dimensional reconstruction data can be obtained through later fusion. The system has the advantages of being simple in structure, low in cost and good in compatibility.

Description

Technical Field

[0001] This invention relates to the field of electron microscopy research technology, specifically to a clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope. Background Technology

[0002] Transmission electron microscopy (TEM) can image and analyze the composition of microscopic regions. Due to its atomic-scale resolution, it is widely used in materials science, biology, and other fields. While conventional TEM images are two-dimensional, some materials science research requires characterizing the three-dimensional structure of materials. Tomography can reconstruct the three-dimensional structure from a series of tilted two-dimensional images by correcting for image feature positions. It can not only reconstruct the morphology of microscopic samples in three-dimensional space but also reconstruct the three-dimensional compositional distribution using X-ray energy dispersive spectroscopy (XEDS). However, the three-dimensional compositional distribution reconstructed by XEDS cannot reach atomic resolution. This is mainly because obtaining a complete sequence of reconstructed three-dimensional images typically requires taking an image every one or two degrees, with an angle range of approximately ±70 degrees. Acquiring this series of images takes about one to two hours. Under such prolonged electron beam irradiation, if images at a few nanometer scales are required, the irradiation dose becomes extremely high, exceeding the tolerance range of most materials.

[0003] For the reasons mentioned above, 3D reconstruction using transmission electron microscopy (TEM) typically achieves a spatial resolution of approximately 1 nanometer, suitable for particle or needle-like samples with sizes ranging from 30 to 300 nanometers. If the sample can be prepared into a needle-like shape with a diameter of approximately 100 nanometers, then after completing the TEM 3D reconstruction, it can be further combined with 3D atomic probe microanalysis (3D Atom Probe) technology to achieve atomic-level resolution characterization. Therefore, a comprehensive characterization scheme combining TEM and 3D Atom Probe has been formed. However, currently available TEM tilting 3D reconstruction devices often struggle to achieve 360° omnidirectional data acquisition, or their mechanical structures and control systems are quite complex.

[0004] Existing technologies, such as Chinese invention patent application number 201610299098.4, entitled "A Transmission Electron Microscope (TEM) Sample Stage for Observing Three-Dimensional Atomic Probe Samples," limit the rotation range of the TEM sample stage to ±75 degrees. Increasing the rotation angle further may result in the electron beam being blocked by the guide rails, preventing sample observation and losing some angular information. Another Chinese invention patent application number 202111557559.0, entitled "A TEM Three-Dimensional Reconstruction Sample Rod Capable of Carrying Nanoparticle Tip Samples and Rotating Autonomously 360°," while achieving 360° rotation, requires the rotation of the sample rod's central axis relative to the external sample rod body, necessitating a comprehensive design for the rotation control device and touchscreen control system. This system is more complex and costly. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a clamping device for a sample rod for three-dimensional reconstruction of a transmission electron microscope. The device uses a control screw integrated with the in-situ mechanical rod to adjust the coaxiality of the sample and the connecting rod, which can accommodate a wider range of sample shape changes.

[0006] This invention is achieved through the following technical solution: In a first aspect, this application provides a clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope, characterized in that it includes a sample rod section, a clamping rod, and a protective frame; The proximal end of the sample rod section is provided with an installation structure for coaxial connection of the in-situ mechanical sample rod, the distal end of the sample rod section is provided with a coaxial locking structure, and the external distal end of the sample rod section is provided with an angle adjustment structure. The proximal end of the clamping rod is connected to the coaxial locking structure, so that the clamping rod is coaxially connected to the sample rod section; The distal end of the clamping rod is provided with a sample fixing structure for fixing the needle-shaped sample; One end of the protective frame is detachably connected to the angle adjustment structure, and the other end extends to the front end of the fixed needle-shaped sample.

[0007] Preferably, the mounting structure includes an insertion hole disposed at the center of the near end face of the sample rod section, and a mounting channel disposed on the near end sidewall of the sample rod section; The insertion hole is used to fit onto the insertion shaft at the distal end of the in-situ mechanical sample rod; the bolt passes through the mounting channel and connects to the insertion shaft to achieve circumferential positioning of the sample rod section and the in-situ mechanical sample rod.

[0008] Preferably, the mounting channel is an arc-shaped groove extending circumferentially along the side wall of the sample rod section.

[0009] Preferably, the coaxial locking structure is a tapered hole arranged along the axis of the sample rod section; The near end of the clamping rod is provided with a tapered rod that mates with the tapered hole.

[0010] Preferably, the clamping rod includes an upper clamping rod and a lower clamping rod arranged symmetrically along its axial plane; The upper clamping rod has a first sample clamping groove at its center plane, and the lower clamping rod has a second sample clamping groove at its center plane. When the planes of the upper clamping rod and the lower clamping rod are in contact with each other, the first sample clamping groove and the second sample clamping groove together form an annular clamping hole for accommodating the needle-shaped sample.

[0011] Preferably, the upper clamping rod includes an upper clamping block and an upper clamping rod. The upper clamping block has a semi-circular cross-section, and its arc-shaped outer surface forms the conical surface of the conical rod. The first sample clamping groove is disposed on the inner wall of the upper clamping block. The lower clamping rod includes a lower clamping block and a lower clamping rod, and its structure is symmetrical to that of the upper clamping rod.

[0012] Preferably, the angle adjustment structure includes a plurality of angle slots evenly distributed circumferentially on the distal sidewall of the sample rod section; One end of the protective frame is provided with a mounting end that is plugged into the angle slot.

[0013] Preferably, the angle slots include two horizontally symmetrically arranged first slides and two vertically symmetrically arranged second slides, and the four angle slots are orthogonally distributed at 90 degrees.

[0014] Preferably, the protective frame includes a protective frame body, which is a door-shaped structure, and has a light-shielding groove at the part corresponding to the observation area of ​​the needle-shaped sample.

[0015] Secondly, this application provides an in-situ mechanical sample rod, characterized in that it includes the clamping device as described in any one of claims 1-9.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: This application provides a clamping device for a sample rod used in 3D reconstruction of a transmission electron microscope (TEM). The proximal end of the sample rod section is coaxially connected to the original rod via a rotatable locking mounting structure, while the distal end utilizes a conical self-centering structure to precisely fix the clamping rod and sample. A reversible protective frame addresses both sample protection and electron beam penetration requirements. Its working principle involves manually rotating the entire clamping module 90 degrees and relocking it. Combined with the tilting function of the TEM's built-in goniometer stage, a large-angle image sequence in orthogonal directions is acquired twice. Finally, image fusion achieves quasi-360-degree 3D reconstruction. This clamping device maintains good compatibility with in-situ mechanical sample rods, eliminating the need to modify the main structure or purchase expensive specialized equipment. Its simple and reliable purely mechanical design avoids the introduction of complex drive and control systems, significantly reducing manufacturing costs and usage risks. Furthermore, its orthogonal orientation switching operation is intuitive and convenient, effectively expanding the imaging angle range while ensuring experimental efficiency and result reliability, providing an economical and practical solution for TEM 3D reconstruction. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is an exploded view of the clamping device of the present invention; Figure 2 This is an assembly diagram of the clamping device of the present invention; Figure 3 This is a schematic diagram of the structure of the sample rod section of the present invention; Figure 4 This is a schematic diagram of the external structure of the clamping rod of the present invention; Figure 5 This is a schematic diagram of the internal structure of the clamping rod of the present invention; Figure 6 This is a schematic diagram of the protective framework of the present invention.

[0019] In the figure: 10, sample rod section; 20, clamping rod; 30, protective frame; A1, rotating groove; A2, first sliding groove; A3, second sliding groove; A4, fixing hole; B1, upper clamping block; B2, upper clamping rod; C1, lower clamping block; C2, lower clamping rod; D1, protective frame body; D2, light-shielding groove. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0022] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0023] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0024] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0025] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0026] A clamping device for a sample rod for three-dimensional reconstruction by transmission electron microscopy includes a sample rod section 10, a clamping rod 20, and a protective frame 30. The sample rod section 10 has a mounting structure at its proximal end for coaxial connection to the in-situ mechanical sample rod, a coaxial locking structure at its distal end, and an angle adjustment structure at the external distal end. The proximal end is defined as the end closest to the Hystron in-situ mechanical sample rod, and the distal end is the end closest to the clamping material.

[0027] The proximal end of the clamping rod is connected to a coaxial locking structure, and the distal end is provided with a sample fixing structure for fixing the sample. One end of the protective frame is connected to the angle adjustment structure, and the other end extends linearly to the front end of the needle-shaped sample to protect the needle-shaped sample.

[0028] The sample rod section in this clamping device serves as a connection and adjustment hub. One end reliably connects to the original rod via an installation structure, and the entire clamping device rotates discretely through an in-situ mechanical rod. The other end is precisely fixed to the clamping rod via a coaxial locking structure, ensuring that the sample remains at the center of rotation of the electron microscope. The protective frame connects to the angle adjustment structure, allowing for angle adjustments as needed. While providing physical protection, it ensures that the electron beam path is not obstructed in any direction, enabling multi-angle data acquisition of needle-shaped samples under the electron beam. The advantages of this clamping device are twofold: firstly, it eliminates the need for a custom-designed, expensive, fully functional rotating sample rod; existing equipment is utilized simply by replacing the front-end module, significantly reducing R&D and procurement costs. Secondly, it is simple and reliable to operate, utilizing the electron microscope's built-in goniometer stage for tilting, avoiding complex internal drive and control circuits and reducing the risk of failure.

[0029] In some embodiments, the mounting structure at the proximal end of the sample rod section 10 includes a socket and a pin fixing structure; the socket is located at the axis of the proximal end face of the sample rod section 10, and the size of the socket matches the insertion axis of the distal end of the in-situ mechanical rod. The socket can be sleeved on the insertion shaft to achieve coaxial connection between the sample rod section 10 and the in-situ mechanical rod. The pin fixing structure includes an installation channel and a bolt on the side wall near the end of the sample rod section 10. The bolt is connected to the insertion shaft through the installation channel to achieve circumferential positioning connection between the sample rod section 10 and the in-situ mechanical rod.

[0030] Furthermore, the mounting channel is a plurality of bolt holes, or an arc-shaped groove A1 extending circumferentially along the side wall of the sample rod section 10.

[0031] When the mounting channel consists of multiple screw holes, these holes are evenly distributed along the circumference of the sidewall and match the positions of the bolt holes on the insertion shaft. Bolts pass through these screw holes and connect to the insertion shaft, thus connecting the sample rod section 10 to the in-situ mechanical rod. This multi-point locking method effectively prevents minor rotations or loosening that may occur during electron microscope tilting or sample rod operation, ensuring absolute stability of the sample position, which is crucial for high-resolution imaging.

[0032] It should be noted that the number and position of the multiple screw holes need to match the position of the bolt holes on the in-situ mechanical rod, that is, the screw hole position of the pin fixing structure is designed according to the number and position of the bolt holes on the in-situ mechanical rod.

[0033] When the mounting channel is an arc-shaped groove A1, multiple arc-shaped grooves A1 are spaced apart on the side wall of the sample rod section. The arc-shaped groove A1 is radially connected to the insertion hole, and the bolt passes through the arc-shaped groove A1 to connect with the insertion shaft.

[0034] In the specific example, the in-situ mechanical rod is equipped with four screws, and two arc-shaped grooves are symmetrically arranged on the side wall of the sample rod section. A bolt is installed at each end of each arc-shaped groove. Compared with the solution that relies entirely on multiple independent screw holes for angle positioning, the arc-shaped grooves provide a continuous adjustment range, reduce the extreme precision requirements for machining and assembly, and allow for a certain installation tolerance. At the same time, it can be more naturally adapted to the multiple circumferentially arranged screws commonly found on in-situ mechanical rods.

[0035] In some embodiments, the coaxial locking structure of the sample rod section 10 is a tapered hole A4 arranged along the axis of the sample rod section 10, and a tapered rod whose proximal end of the clamping rod 20 engages with the tapered hole.

[0036] During installation, the proximal end of the clamping rod is inserted into the conical hole, and the coaxial positioning and locking of the sample rod section 10 clamping rod 20 can be achieved by the cooperation of the inner and outer conical surfaces.

[0037] The taper of the conical hole is 1°-5° on one side, and correspondingly, the taper of the clamping rod is the same as that of the conical rod.

[0038] This coaxial locking structure with a conical fit utilizes the self-centering and self-locking mechanical principle of the conical surface to achieve rapid, precise, and reliable connection and positioning between the clamping rod and the sample rod section. When the conical end of the clamping rod is inserted into the corresponding conical hole, the inner and outer conical surfaces automatically guide and correct their relative positions under axial pressure, ensuring that the axis of the clamping rod is highly aligned with the axis of the sample rod section. This guarantees that the sample remains near the rotation center of the electron microscope's goniometer stage during subsequent tilting. Simultaneously, the conical fit generates significant static friction after clamping, creating a stable self-locking state and effectively preventing axial displacement or circumferential rotation that may occur during sample rod operation or electron microscope tilting. This simplifies assembly, reduces the technical requirements for operators, and its simple structure and high rigidity facilitate stable and high-precision sample clamping within the limited sample chamber space of a transmission electron microscope.

[0039] In some embodiments, the sample fixing structure of the clamping rod is a clamping hole provided in the axis of the clamping rod.

[0040] The clamping rod includes an upper clamping rod and a lower clamping rod symmetrically arranged along the axial plane. The upper clamping rod and the lower clamping rod have the same structure. A sample clamping groove is provided at the center of the plane of the upper clamping rod. The sample clamping groove is located at the axis and runs through the entire clamping rod. The planes of the upper clamping rod and the lower clamping rod fit together, and the two sample clamping grooves form an annular clamping hole.

[0041] For example, when fixing a needle-shaped sample, one end of the needle-shaped sample is placed in the sample clamping groove between the upper clamping rod and the lower clamping rod, and the rest of the needle-shaped sample extends out of the sample clamping groove. The upper clamping rod and the lower clamping rod are pushed into the conical hole, and the upper clamping rod and the lower clamping rod naturally close under the action of the conical hole, thus achieving the clamping and fixing of the needle-shaped sample.

[0042] Furthermore, the upper clamping rod includes an upper clamping block B1 and an upper clamping rod B2. The cross-section of the upper clamping rod B2 is a semi-circular structure, and its arc surface is a conical surface. The upper clamping block B1 is a planar structure and is located at the far end of the upper clamping rod. The sample clamping groove is located on the inner wall of the upper clamping block B1.

[0043] The lower clamping rod includes a lower clamping block B1 and a lower clamping rod B2, and its structure is the same as that of the upper clamping rod, so it will not be described in detail here.

[0044] In this embodiment, the clamping rod is divided into an upper clamping rod and a lower clamping rod along the axial plane. Semi-circular sample clamping grooves are provided on both the upper and lower clamping rods. These grooves are closed by two perfectly symmetrical clamping blocks guided by a precisely fitted conical hole. The semi-circular grooves on their inner walls naturally form a complete circular clamping hole. The central axis of this hole strictly coincides with the theoretical axis of the clamping rod, and consequently, with the sample rod section. This fundamentally ensures that the clamped sample is precisely located at the rotation center of the entire sample rod, providing a crucial geometric prerequisite for subsequent large-angle tilt imaging and high-precision 3D reconstruction.

[0045] In some embodiments, an angle adjustment structure is provided on the outer side of the distal end of the sample rod 10. The angle adjustment structure includes multiple angle slots, which are evenly distributed around the circumference of the sidewall of the distal end of the sample rod. The angle slots are connected to a protective frame. The protective frame is connected to different angle slots, so that the angle of the protective frame can be changed to adapt to different sample tilting directions.

[0046] See Figure 3 In a specific example, the outer wall of the sample rod section is provided with four angle slots: two symmetrical horizontal angle slots A2 and two symmetrical vertical angle slots A3. The four angle slots are evenly distributed in a 90° circle, and the end of the protective frame can be inserted into the angle slots.

[0047] By creating multiple angle slots on the sidewalls, operators can selectively insert the protective frame's pins into specific matching slots according to different experimental stages. This allows the protective frame to remain in one orientation during large-angle tilt data acquisition in one direction, providing physical protection for fragile needle-like samples. When data acquisition in that direction is completed and the entire clamping module is rotated a specific angle for a second orthogonal tilt, the protective frame can simply be removed and inserted into another angle slot that matches the new clamping module's orientation. This design ensures that the protective frame effectively protects the sample tip throughout both orthogonal data acquisitions, while simultaneously avoiding the electron beam's path in each specific tilt direction, thus preventing obstruction of the imaging area.

[0048] In another embodiment, the angle adjustment structure consists of multiple angle insertion holes arranged on the distal end face of the sample rod section, with the multiple insertion holes circumferentially distributed, and the end of the protective frame is provided with a pin shaft that engages with the angle insertion holes.

[0049] In some embodiments, the protective frame 30 includes a protective frame body D1 and a light-shielding groove D2; the protective frame body D1 is a gate-shaped structure, with both ends used to connect to the angle adjustment structure, i.e., to be inserted into the angle slot, while the side walls of the protective frame are located on both sides of the clamping rod, and the front end of the protective frame is located at the front end of the needle-shaped sample; the light-shielding groove D2 is provided on the surface and bottom surface of the protective frame body D1 and is located in the needle-shaped sample area to avoid blocking the electron beam.

[0050] Furthermore, the front end of the protective frame body is chamfered, which serves as a guide and reduces the risk of collision damage with the internal components of the electron microscope.

[0051] Example 1 This invention provides a specific embodiment of a clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope. Its structure can be referred to... Figure 1 The exploded view shown and Figure 2 The assembly diagram shown is illustrated. The clamping device mainly consists of three parts: sample rod section 10, clamping rod 20, and protective frame 30.

[0052] The sample rod section 10 has a multi-step cylindrical structure, and its proximal end matches the front end of a commercially available Hystron in-situ mechanical sample rod. A cylindrical insertion hole is formed at the center of the proximal end face, and the diameter of the insertion hole matches the outer diameter of the insertion shaft at the front end of the in-situ mechanical rod to achieve preliminary coaxial positioning. On the proximal sidewall of the sample rod section 10, two arc-shaped grooves A1 are symmetrically formed along the circumference, and the curvature of the arc-shaped grooves is slightly greater than 90 degrees. Four threaded holes are evenly distributed along the circumference on the insertion shaft of the in-situ mechanical rod. During assembly, the insertion hole of the sample rod section 10 is fitted into the insertion shaft, and the two arc-shaped grooves A1 on it are aligned with the two threaded holes on the insertion shaft. Four bolts are screwed through the arc-shaped grooves into the threaded holes, with two bolts tightened at one end of the arc-shaped groove and the other two bolts tightened at the other end, thereby firmly fixing the sample rod section 10 to the in-situ mechanical rod.

[0053] At the distal end of the sample rod section 10, a coaxial conical hole A4 is formed along its axis, with a single-sided cone angle of 3°. On the cylindrical outer wall at the distal end of the sample rod section 10, four angular slots are evenly distributed along the circumference, including two horizontal first grooves A2 and two vertical second grooves A3, with the four grooves orthogonally distributed at 90 degrees.

[0054] The clamping rod 20 is composed of an upper clamping rod and a lower clamping rod with identical structures. (Refer to...) Figure 4 and Figure 5 The upper clamping rod is integrally formed from the upper clamping block B1 and the upper clamping rod B2. The upper clamping block B2 has a semi-circular cross-section, and its arc-shaped outer surface is a conical surface that matches the conical hole A4. The upper clamping rod B1 is a planar thin-plate structure, with a thinner distal end and a proximal end connected to the upper clamping block B2. A semi-circular sample clamping groove is formed along the axis at the center of the inner wall of the upper clamping blocks B1 and B2. The lower clamping rod is composed of the structurally symmetrical lower clamping block C1 and the lower clamping rod C2, and its inner wall also has a semi-circular sample clamping groove.

[0055] During sample loading, first lay the lower clamping rod flat and place a needle-shaped sample with a tip diameter of approximately 100 nanometers and a tip diameter of approximately 1 millimeter into its sample clamping groove. Then, close the upper clamping rod, making the planes of the upper and lower clamping rods fit together. At this point, the two semi-circular clamping grooves together form a complete cylindrical clamping hole, constraining the needle-shaped sample within it. Subsequently, align the proximal end of the assembled clamping rod 20 with the conical hole A4 of the sample rod section 10 and push it in as a whole. Due to the self-centering effect of the conical surface, the clamping rod 20 is automatically guided to a position coaxial with the sample rod section 10. With further advancement, the radial component force generated by the conical surface causes the upper and lower clamping rods to close tightly, thereby firmly holding the needle-shaped sample. The frictional force generated by the conical surface mating also achieves axial and circumferential self-locking, ensuring the stability of the sample position in subsequent operations.

[0056] The protective frame 30, as Figure 6As shown, its main body is a stepped "n"-shaped structure, namely the protective frame body D1. Its wider end is the mounting end, which can be inserted into the angular slot at the distal end of the sample rod section 10, and fixed by an interference fit. Its narrower front end is thin and extends forward to the front of the needle-shaped sample. A light-shielding groove D2 is provided on the protective frame body D1 at the location corresponding to the sample observation area. This light-shielding groove significantly reduces the material thickness of the frame body to avoid blocking the incident electron beam when the sample is tilted for imaging.

[0057] The working principle and operation procedure are as follows: First data acquisition: The mounting end of the protective frame 30 is horizontally inserted into the two first sliding grooves A2 of the sample rod section 10, ensuring it is in a horizontal position. The assembled clamping device is then installed onto the in-situ mechanical rod. By adjusting the fine-tuning screws on the in-situ mechanical rod, the tip position of the needle-like sample can be finely adjusted to precisely locate it at the rotation center of the transmission electron microscope's goniometer stage. Subsequently, the sample rod is inserted into the electron microscope. Using the goniometer stage on the electron microscope, the sample rod is driven to tilt in one direction, acquiring an image every 1-2 degrees, with a tilt range of ±45 degrees or even ±75 degrees. During this process, the horizontally placed protective frame 30 provides effective protection for the protruding tip of the needle-like sample, and its light-shielding groove D2 ensures that the electron beam can pass through the sample without obstruction.

[0058] Orientation Conversion and Second Data Acquisition: After completing the first tilt-series imaging, the sample rod is safely removed from the electron microscope. The four bolts securing sample rod section 10 are loosened, and the entire clamping device is removed from the original mechanical rod. Then, the clamping device is rotated 90 degrees and reinstalled onto the original mechanical rod, and the bolts are tightened at the new angle. Simultaneously, the protective frame 30 is pulled out of the first groove A2, rotated 90 degrees, and vertically inserted into the two second grooves A3 of the sample rod section 10. At this point, the protective frame 30 is in a vertical orientation.

[0059] The sample rod, now repositioned, is reinserted into the electron microscope. Using the same goniometer stage, the sample rod is tilted at a large angle in another orthogonal direction, and a second series of images is acquired.

[0060] 3D Reconstruction: The series of 2D image data acquired through two orthogonal tilting operations are input into the 3D reconstruction software. Since the sample orientation is known from the two data acquisitions, the software's image registration and fusion algorithms can synthesize the 3D structural information of the sample at a near-perfect spherical angle, thus achieving quasi-360-degree 3D reconstruction.

[0061] The device in this embodiment, by modularly replacing the front end of the existing in-situ mechanical rod, cleverly realizes the quasi-full-angle data acquisition function that originally required a complex full-rotation mechanism through a simple and reliable mechanical structure and discrete manual orientation adjustment. This significantly reduces cost and system complexity, while ensuring operational feasibility and sample imaging quality.

[0062] Example 2 This application provides an in-situ mechanical sample rod, including an in-situ mechanical sample rod and a clamping device as described in Embodiment 1 connected to its distal end.

[0063] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope, characterized in that, Includes sample rod section, clamping rod and protective frame; The proximal end of the sample rod section is provided with an installation structure for coaxial connection of the in-situ mechanical sample rod, the distal end of the sample rod section is provided with a coaxial locking structure, and the external distal end of the sample rod section is provided with an angle adjustment structure. The proximal end of the clamping rod is connected to the coaxial locking structure, so that the clamping rod is coaxially connected to the sample rod section; The distal end of the clamping rod is provided with a sample fixing structure for fixing the needle-shaped sample; One end of the protective frame is detachably connected to the angle adjustment structure, and the other end extends to the front end of the fixed needle-shaped sample.

2. The clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope according to claim 1, characterized in that, The mounting structure includes an insertion hole located at the center of the near end face of the sample rod section, and a mounting channel located on the near end sidewall of the sample rod section. The insertion hole is used to fit onto the insertion shaft at the distal end of the in-situ mechanical sample rod; the bolt passes through the mounting channel and connects to the insertion shaft to achieve circumferential positioning of the sample rod section and the in-situ mechanical sample rod.

3. The clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope according to claim 2, characterized in that, The installation channel is an arc-shaped groove extending circumferentially along the side wall of the sample rod section.

4. The clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope according to claim 1, characterized in that, The coaxial locking structure is a tapered hole arranged along the axis of the sample rod section; The near end of the clamping rod is provided with a tapered rod that mates with the tapered hole.

5. A clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope according to claim 1, characterized in that, The clamping rod includes an upper clamping rod and a lower clamping rod arranged symmetrically along its axial plane; The upper clamping rod has a first sample clamping groove at its center plane, and the lower clamping rod has a second sample clamping groove at its center plane. When the planes of the upper clamping rod and the lower clamping rod are in contact with each other, the first sample clamping groove and the second sample clamping groove together form an annular clamping hole for accommodating the needle-shaped sample.

6. The clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope according to claim 1, characterized in that, The upper clamping rod includes an upper clamping block and an upper clamping rod. The upper clamping block has a semi-circular cross-section, and its arc-shaped outer surface forms the conical surface of the conical rod. The first sample clamping groove is disposed on the inner wall of the upper clamping block. The lower clamping rod includes a lower clamping block and a lower clamping rod, and its structure is symmetrical to that of the upper clamping rod.

7. A clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope according to claim 1, characterized in that, The angle adjustment structure includes multiple angle slots evenly distributed circumferentially on the distal sidewall of the sample rod section. One end of the protective frame is provided with a mounting end that is plugged into the angle slot.

8. A clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope according to claim 1, characterized in that, The angle slots include two horizontally symmetrical first slides and two vertically symmetrical second slides, and the four angle slots are orthogonally distributed at 90 degrees.

9. A clamping device for a sample rod used in three-dimensional reconstruction of a transmission electron microscope according to claim 1, characterized in that, The protective frame includes a protective frame body, which is a door-shaped structure with a light-shielding groove corresponding to the observation area of ​​the needle-shaped sample.

10. An in-situ mechanical sample rod, characterized in that, Includes the clamping device as described in any one of claims 1-9.

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