Adapted standard sample holder for transmission electron microscopy in situ cryogenic sample holder

Abstract

This invention relates to the field of transmission electron microscopy (TEM) technology, and provides an in-situ ultra-low temperature sample holder adapted for standard samples in TEM. The holder includes a main body, a U-shaped flow channel, a cooling connector, and a flexible cooling component. The main body has a mounting cavity, with the front end serving as the observation end. The U-shaped flow channel passes through the mounting cavity and includes an input section, a bent section, and a return section connected sequentially. The bent section is adjacent to the observation end and is used to transport refrigerant. The cooling connector is connected to the outside of the bent section. One end of the flexible cooling component is connected to the cooling connector, and the other end extends outward from the mounting cavity and has a support for placing the sample. This invention effectively absorbs vibrations generated by refrigerant flow through the design of the flexible cooling component, preventing vibration transmission to the sample. Simultaneously, the U-shaped flow channel optimizes the cooling path to improve temperature control accuracy, enhances TEM imaging stability, and achieves a stable ultra-low temperature environment for the sample.

Description

Technical Field

[0001] This invention relates to the field of transmission electron microscopy, and more particularly to a standard sample in-situ cryogenic sample holder for transmission electron microscopy. Background Technology

[0002] Transmission electron microscopy (TEM), as a core instrument for atomic-scale structural analysis in materials science and condensed matter physics, relies heavily on precise control of the sample environment for its application depth. Under extremely low temperatures, many key physical processes, such as charge density wave phase transitions, direct observation of the bandgap in superconducting materials, spin state transitions in magnetic materials, and the nucleation and growth mechanisms of lithium dendrites in lithium batteries, require in-situ high-resolution imaging to reveal their microscopic dynamics. However, the spatial constraints of the TEM sample chamber are extremely stringent, requiring the in-situ cryogenic sample holder to achieve a stable cryogenic environment within a limited volume, while simultaneously avoiding interference with the electron beam path and imaging quality.

[0003] Vibration interference is particularly prominent. In continuous flow cooling schemes based on liquid nitrogen or liquid helium Dewar flasks, the refrigerant continuously boils within the transmission pipeline, generating microbubbles. The bursting of these bubbles triggers high-frequency mechanical vibrations. These vibrations are transmitted to the sample location without attenuation through traditional rigid cooling finger structures, resulting in image drift and edge blurring during high-magnification imaging, severely impairing atomic-level resolution. While alternative solutions using small mechanical refrigerators avoid liquid phase transitions, the reciprocating motion of the compressor piston and fluctuations in working fluid pressure still introduce significant mechanical vibrations, affecting imaging stability. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in related technologies. To this end, this invention proposes an in-situ ultra-low temperature sample holder adapted for standard samples in transmission electron microscopy (TEM), which aims to effectively isolate vibration interference, improve the imaging stability of TEM, and simultaneously achieve rapid cooling of the sample and a stable ultra-low temperature environment.

[0005] According to embodiments of the present invention, the in-situ cryogenic sample holder for transmission electron microscopy of standard samples includes: The rod body has an internal mounting cavity, and the front end of the rod body is the observation end; The U-shaped flow channel tube is inserted into the mounting cavity. The U-shaped flow channel tube includes an input pipe section, a bent pipe section and a return pipe section connected in sequence. The bent pipe section is adjacent to the observation end. The U-shaped flow channel tube is used to transport refrigerant. A cooling-conducting connector is connected to the outside of the bent pipe section; A flexible cooling conductor, one end of which is connected to the cooling connector, and the other end extends outward from the mounting cavity and is provided with a support member for placing a sample.

[0006] According to embodiments of the present invention, the in-situ ultra-low temperature sample holder for transmission electron microscopy (TEM) of the adapted standard sample effectively absorbs the vibration generated by the refrigerant flow through the design of the flexible cooling component, avoiding the vibration from being transmitted to the sample. At the same time, the U-shaped flow channel optimizes the cooling path to improve the temperature control accuracy, effectively isolates vibration interference, improves the imaging stability of TEM, and simultaneously achieves rapid cooling of the sample and a stable ultra-low temperature environment.

[0007] According to one embodiment of the present invention, the cooling connector includes: The first component has a first U-shaped groove at one end; The second part has a second U-shaped groove at one end. The second part is connected to the first part. The first U-shaped groove and the second U-shaped groove are correspondingly arranged to form a U-shaped channel to accommodate the bent pipe section. The end is connected between the first component and the second component, and the end is connected to one end of the flexible cooling component.

[0008] According to one embodiment of the present invention, the first split body is provided with a first T-shaped groove at the end away from the first U-shaped groove, and the second split body is provided with a second T-shaped groove at the end away from the second U-shaped groove. The first T-shaped groove and the second T-shaped groove are provided correspondingly to form a snap-fit ​​groove, and the end is snapped into the snap-fit ​​groove.

[0009] According to one embodiment of the present invention, it further includes a thermal insulation support member, which is sleeved on the outside of the U-shaped flow channel pipe and supported on the inner wall of the mounting cavity.

[0010] According to one embodiment of the present invention, the thermal insulation support includes: A support ring, the outer wall of which is supported by the inner wall of the mounting cavity; The first protrusion is disposed within the support ring; The second protrusion is located inside the support ring and is positioned opposite to the first protrusion. Both the input pipe section and the return pipe section pass through the support ring and abut against the first protrusion and the second protrusion.

[0011] According to one embodiment of the present invention, the U-shaped flow channel is made of a non-magnetic material; The cooling connector is a heat-conducting metal block; And / or, the flexible cooling component is a thermally conductive metal braided strip.

[0012] According to one embodiment of the present invention, a clamping assembly is further included, the clamping assembly comprising: Mounting frame, one end of which is connected to the rod body, and a support base is provided at the end of the mounting frame away from the rod body; The lower insulation component is placed on the support base, and the support component is placed on the lower insulation component; An upper insulation component covers the support component and is connected to the lower insulation component. The upper insulation component and / or the lower insulation component are provided with a clearance opening, and the flexible cooling component passes through the clearance opening.

[0013] According to one embodiment of the present invention, the clamping assembly further includes a protective cover, the protective cover having a plurality of protective feet, the plurality of protective feet being supported around the periphery of the support base.

[0014] According to one embodiment of the present invention, it further includes a radiation shielding shell, which is connected to the observation end of the rod body and covers the flexible cooling component and the support component. The radiation shielding shell has a through hole, which corresponds to the support component. And / or, the support is provided with a temperature sensor.

[0015] According to one embodiment of the present invention, a vacuum sealing assembly is further included, the vacuum sealing assembly being disposed at the tail end of the sample rod body, and the end of the U-shaped flow channel tube away from the bent tube section is connected to an external cooling system through the vacuum sealing assembly.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or related technologies, the drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the in-situ ultra-low temperature sample rod for transmission electron microscopy of adapted standard samples provided in an embodiment of the present invention.

[0019] Figure 2 This is a schematic diagram of the exploded structure of the in-situ ultra-low temperature sample rod for transmission electron microscopy of adapted standard samples provided in an embodiment of the present invention.

[0020] Figure 3 yes Figure 2 A magnified view of a portion of point A in the middle.

[0021] Figure 4 This is a cross-sectional view of the in-situ cryogenic sample holder for a transmission electron microscope adapted to standard samples provided in this embodiment of the invention.

[0022] Figure 5 yes Figure 4 A magnified view of a section at point B in the middle.

[0023] Figure 6 This is a partial exploded view of the clamping assembly in the in-situ ultra-low temperature sample holder for the transmission electron microscope provided in this embodiment of the invention.

[0024] Figure 7 This is a schematic diagram of the structure of the radiation shielding shell provided in an embodiment of the present invention.

[0025] Figure label: 1. Rod body; 2. U-shaped flow channel pipe; 21. Input pipe section; 22. Bent pipe section; 23. Return pipe section; 3. Cooling conductor connector; 31. First split part; 311. First U-shaped groove; 312. First T-shaped groove; 32. Second split part; 321. Second U-shaped groove; 33. End; 4. Flexible cooling conductor; 41. Support part; 411. Temperature sensor; 5. Thermal insulation support part; 51. Support ring; 52. First protrusion; 53. Second protrusion; 6. Clamping assembly; 61. Mounting frame; 611. Support base; 62. Lower thermal insulation part; 621. Clearance opening; 63. Upper thermal insulation part; 64. Protective cover; 7. Radiation shielding shell; 8. Vacuum sealing assembly; 81. Through hole; 200. Sample. Detailed Implementation

[0026] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0027] In the description of the embodiments of the present invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention 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. Therefore, they should not be construed as limitations on the embodiments of the present invention. In addition, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] In the description of the embodiments of the present invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0029] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0030] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0031] Traditional in-situ cryogenic techniques for transmission electron microscopy (TEM) suffer from several drawbacks due to limited sample chamber space, including vibration interference, insufficient temperature control stability and uniformity, and incompatibility with standard samples. Micro-vibrations caused by coolant boiling or refrigerator piston movement are difficult to suppress, leading to image drift and blurring at high magnification. Furthermore, existing methods struggle to achieve precise and stable closed-loop temperature control within the sample region, and the complex cooling chain structure requires customized sample holders, making direct adaptation to standard 3mm diameter samples impossible. These limitations severely restrict atomic-level high-resolution observations and in-situ studies of cryogenic physics phenomena.

[0032] Please refer to the following for details. Figures 1 to 3This application proposes an in-situ ultra-low temperature sample rod adapted for transmission electron microscopy (TEM) of standard samples. By constructing a collaborative working mechanism of the rod body 1, U-shaped flow channel 2, cold-conducting connector 3, and flexible cold-conducting component 4, the aforementioned technical problems are effectively solved. The sample rod utilizes the U-shaped flow channel 2 to deliver refrigerant to the bent pipe section 22 near the observation end, and the cold energy is transferred to the flexible cold-conducting component 4 via the cold-conducting connector 3. One end of the flexible cold-conducting component 4 is connected to the cold-conducting connector 3, and the other end extends outside the mounting cavity and is equipped with a support 41 for placing the sample 200. This effectively decouples the cooling source from the sample stage, reduces vibration transmission, and ensures stable and efficient cooling and observation of the standard sample.

[0033] Understandably, the rod body 1 can be constructed as a hollow cylindrical or polygonal tubular structure, forming an internal mounting cavity. The front end of the rod body 1 is the observation end, which can serve as one end inserted into the sample chamber of the transmission electron microscope. The U-shaped flow channel 2 passes through the mounting cavity and includes an input pipe section 21, a bent pipe section 22, and a return pipe section 23 connected in sequence. The bent pipe section 22 is positioned adjacent to the observation end. The main function of the U-shaped flow channel 2 is to transport refrigerant. For example, the U-shaped flow channel 2 can be formed by bending a single, continuous pipe section into a U-shape. Its input pipe section 21 and return pipe section 23 are connected to the refrigeration system via external interfaces. The refrigerant circulates within the pipe, carrying the cooling energy to the bent pipe section 22.

[0034] Furthermore, the cold-conducting connector 3 is connected to the outside of the bent section 22 of the U-shaped flow channel 2. The function of the cold-conducting connector 3 is to transfer the cold energy in the bent section 22 outwards. For example, the cold-conducting connector 3 can be a solid metal block, tightly attached to the outer surface of the bent section 22 by means of bolt fixing, compression, or filling with a heat-conducting medium to ensure thermal contact. In addition, one end of the flexible cold-conducting component 4 is connected to the cold-conducting connector 3, and the other end extends outwards from the mounting cavity and is provided with a support 41. The support 41 is used to place a standard transmission electron microscope sample 200 with a diameter of 3 mm. For example, the flexible cold-conducting component 4 can be a flexible strip made of thin metal sheet or metal wire bundle, one end of which is fixed to the cold-conducting connector 3 by bolts or welding, and the other end is connected to a ring-shaped support 41. The sample 200 can be placed directly on the ring. The flexible structure helps to isolate vibrations caused by refrigerant flow or external refrigeration system while transferring cold energy.

[0035] In this embodiment, the in-situ cryogenic sample holder for a transmission electron microscope (TEM) of adapted standard samples guides the refrigerant to the observation end via a U-shaped flow channel 2, and utilizes a heat-conducting connector 3 and a flexible heat-conducting component 4 to achieve efficient and flexible transfer of cooling. This effectively suppresses the transmission of micro-vibrations generated by refrigerant flow to the sample end, ensuring a low vibration level in the sample area, thus supporting atomic-level high-resolution imaging. Simultaneously, this structure provides a stable and controllable cryogenic environment for standard 3mm diameter samples, solving the problems of vibration interference, insufficient temperature control stability, and sample adaptation difficulties inherent in traditional techniques when sample chamber space is limited.

[0036] Please refer to the reference. Figures 3 to 5 This application further proposes that the cooling conductor 3 includes a first part 31, a second part 32, and an end 33. One end of the first part 31 is provided with a first U-shaped groove 311; one end of the second part 32 is provided with a second U-shaped groove 321. The second part 32 is connected to the first part 31. The first U-shaped groove 311 and the second U-shaped groove 321 are correspondingly arranged to form a U-shaped channel for accommodating the bent pipe section 22. The end 33 is connected between the first part 31 and the second part 32, and the end 33 is connected to one end of the flexible cooling conductor 4.

[0037] The first component 31 is a part of the cooling-conducting connector 3, with a U-shaped groove at one end for contacting the bent pipe section 22 and forming a covering structure. The second component 32 is another part of the cooling-conducting connector 3, also with a U-shaped groove at one end, which cooperates with the U-shaped groove of the first component 31 to form a U-shaped channel that tightly covers the bent pipe section 22. The second component 32 can be made of the same material and processed as the first component 31, and can be tightly connected to the first component 31 by mechanical connection methods such as bolts, rivets, or welding to ensure the integrity and stability of the U-shaped channel. Alternatively, it can be designed with snap-fit ​​or dovetail joints to allow the first and second components 31 to self-align and fit tightly during assembly, forming a whole, thereby simplifying the installation process and improving the reliability of the connection. The end 33 is a component in the cooling-conducting connector 3 used to connect the flexible cooling component 4. It is fixed between the first component 31 and the second component 32, serving as an interface for the transfer of cold energy from the main body of the cooling-conducting connector 3 to the flexible cooling component 4. The end 33 can be designed with threaded holes or welding surfaces to connect with the flexible heat conduction component 4 by means of bolt fastening or brazing, so as to ensure the continuity of the heat conduction path.

[0038] Through the above technical solution, the cooling connector 3 is designed as a mating structure composed of a first part 31 and a second part 32. The U-shaped channel formed by the first U-shaped groove 311 and the second U-shaped groove 321 enables the enveloping installation of the bent pipe section 22. This not only facilitates assembly within a confined installation cavity and secures the pipe section through mating, but also ensures the tightness of the connection between components, guaranteeing the stability of the heat conduction path in extremely low-temperature environments. This effectively solves the problems of difficult installation and insufficient thermal contact in traditional integrated structures within confined spaces, thus providing a stable and efficient extremely low-temperature environment for the sample. Furthermore, the detachable design of the first part 31 and the second part 32 simplifies assembly and facilitates the replacement of aged or damaged components.

[0039] like Figure 3 As shown, this application further proposes that the first split 31 is provided with a first T-shaped groove 312 at one end away from the first U-shaped groove 311, and the second split 32 is provided with a second T-shaped groove at one end away from the second U-shaped groove 321. The first T-shaped groove 312 and the second T-shaped groove are provided correspondingly to form a snap-fit ​​groove. The end 33 is snapped into the snap-fit ​​groove, and the cross-section of the end 33 is T-shaped.

[0040] Specifically, the first T-slot 312 and the second T-slot are specific geometric structures provided on the first and second parts 31 and 32 of the cooling conductor connector 3. They are typically in the form of grooves with a "T"-shaped cross-section, designed to provide mechanical limiting and connection functions. The first T-slot 312 and the second T-slot can be precisely aligned during assembly of the first and second parts 31 and 32, forming a complete internal space for accommodating the end 33, i.e., a snap-fit ​​groove. The cross-section of the end 33 is designed in a T-shape to mechanically engage with the T-shaped snap-fit ​​groove formed inside the cooling conductor connector 3, utilizing the geometric interlocking characteristics of the T-shaped structure to achieve a stable connection. This creates a stable mechanical interlocking structure between the end 33 and the cooling conductor connector 3, effectively preventing loosening or detachment under extremely low temperature environments, thermal expansion and contraction, and micro-vibration, thereby ensuring the reliability and stability of the connection between the flexible cooling conductor 4 and the cooling conductor connector 3. In addition, the T-shaped snap-fit ​​structure increases the contact area between the end 33 and the snap-fit ​​groove, optimizes the heat conduction path, and significantly reduces the thermal resistance, thereby improving the heat flow transfer efficiency from the bent tube section 22 to the flexible cooling component 4, ensuring that the cooling capacity of the refrigerant can be efficiently transferred to the sample area.

[0041] In one embodiment, the first T-groove 312 and the second T-groove can also be filled with a small amount of thermally conductive medium to achieve better thermal contact and improve thermal conductivity.

[0042] like Figure 3 and Figure 5As shown, this application further proposes that the in-situ ultra-low temperature sample rod for the transmission electron microscope of the standard sample also includes a thermal insulation support 5, which is sleeved outside the U-shaped flow channel tube 2 and supported on the inner wall of the mounting cavity.

[0043] The thermal insulation support 5 is a structural component with low thermal conductivity. Its core function is to provide necessary mechanical support while effectively blocking heat transfer from the external environment to the refrigerant inside the U-shaped flow channel tube 2. Specifically, the thermal insulation support 5 can be made of polymer materials such as polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK). The thermal insulation support 5 is fitted onto the outside of the U-shaped flow channel tube 2 to ensure a tight and stable contact between the thermal insulation support 5 and the U-shaped flow channel tube 2, thereby providing direct mechanical support and efficient thermal insulation. Specifically, the thermal insulation support 5 is a sleeve-shaped component that matches the shape of the U-shaped flow channel tube 2 and is firmly fixed by interference fit or adhesive bonding.

[0044] The thermal insulation support 5 rests on the inner wall of the mounting cavity. Its function is to effectively transfer the supporting force borne by the U-shaped flow channel 2 to the rod body 1 and to provide a stable fixing point using the inner wall of the mounting cavity. In practice, the outer diameter of the thermal insulation support 5 can be tightly fitted with the inner diameter of the mounting cavity, achieving stable support through friction or a limiting structure. In addition, the outer wall of the thermal insulation support 5 can be provided with protrusions or grooves to cooperate with the corresponding structures on the inner wall of the mounting cavity to achieve precise positioning and reliable support.

[0045] Through the above technical solution, a dual barrier of physical support and thermal insulation is constructed between the U-shaped flow channel tube 2 and the inner wall of the mounting cavity. The thermal insulation support 5 is sleeved on the outside of the U-shaped flow channel tube 2, which on the one hand can firmly fix the U-shaped flow channel tube 2 in a predetermined position within the mounting cavity, effectively suppressing minor vibrations caused by refrigerant flow or external environmental disturbances. On the other hand, by supporting the inner wall of the mounting cavity, the thermal insulation support 5 reduces the direct heat conduction path between the U-shaped flow channel tube 2 and the rod body 1, significantly reducing the heating effect of the external environment on the refrigerant, ensuring cooling efficiency, and enabling the sample area to maintain a lower temperature.

[0046] like Figure 5 As shown, this application further proposes that the above-mentioned thermal insulation support 5 includes a support ring 51, a first protrusion 52 and a second protrusion 53. The outer wall of the support ring 51 is supported on the inner wall of the mounting cavity; the first protrusion 52 is disposed inside the support ring 51; the second protrusion 53 is disposed inside the support ring 51 and is disposed opposite to the first protrusion 52. The inlet pipe section 21 and the return pipe section 23 both pass through the support ring 51 and abut against the first protrusion 52 and the second protrusion 53.

[0047] Specifically, the support ring 51, as the main structure of the thermal insulation support 5, has its outer wall in close contact with the inner wall of the mounting cavity, and its main function is to provide overall support for the U-shaped flow channel 2. The first protrusion 52 and the second protrusion 53 are both located inside the support ring 51 and are positioned opposite each other. Their main function is to abut against the input pipe section 21 and the return pipe section 23 of the U-shaped flow channel 2, thereby securing and limiting the U-shaped flow channel 2. In one embodiment, the first protrusion 52 and the second protrusion 53 can be designed as arc-shaped protrusions, forming a through-channel with the inner wall of the support ring 51, so that the input pipe section 21 and the return pipe section 23 can be effectively constrained. The first protrusion 52 and the second protrusion 53 are integrally formed with the support ring 51, or embedded in the support ring 51 as independent low thermal conductivity components to ensure structural stability and thermal insulation effect. Both the inlet pipe section 21 and the return pipe section 23 pass through the support ring 51 and abut against the first protrusion 52 and the second protrusion 53. The physical contact between the inlet pipe section 21 and the return pipe section 23 and the first protrusion 52 and the second protrusion 53 aims to minimize the contact area, for example, through point contact or line contact, thereby reducing the conduction of cold energy from the U-shaped flow channel pipe 2 to the thermal insulation support 5 and ensuring good thermal insulation performance.

[0048] This application further proposes that the U-shaped flow channel tube 2 is made of a non-magnetic high-strength material, preferably titanium alloy; optionally, the cooling connector 3 is a high thermal conductivity metal block; optionally, the flexible cooling component 4 is a high thermal conductivity metal braided strip, of course, other forms such as filaments, sheets, etc. can also be used, as long as they are flexible.

[0049] Specifically, non-magnetic high-strength materials refer to materials that do not produce or only produce extremely weak magnetic responses in the strong magnetic field environment of a transmission electron microscope, while possessing excellent mechanical properties. Their function is to avoid magnetic interference with the electron beam path, ensure imaging stability, and guarantee the structural integrity of the flow channel under extremely low temperatures and refrigerant pressure fluctuations, preventing deformation or breakage. Besides preferred titanium alloys, other non-magnetic austenitic stainless steels (such as 316L stainless steel) or certain nickel-based alloys can also be used; these materials can provide sufficient strength while maintaining non-magnetic properties.

[0050] The heat-conducting connector 3 serves as a bridge for heat transfer between the U-shaped flow channel 2 and the flexible heat-conducting component 4, and its thermal conductivity directly affects the cooling efficiency. The high thermal conductivity metal block refers to a solid block structure made of a metal material with extremely high thermal conductivity. Its function is to minimize thermal resistance and ensure that the cooling capacity of the refrigerant can be efficiently transferred from the U-shaped flow channel 2 to the flexible heat-conducting component 4, thereby achieving rapid cooling of the sample area and maintaining extremely low temperatures. For example, a high-purity oxygen-free copper block or a specially treated high-purity aluminum alloy block can be used to ensure excellent thermal conductivity.

[0051] The flexible cooling conductor 4 connects the cooling conductor connector 3 and the support 41, and its structural design balances cold transfer and vibration isolation. The high thermal conductivity metal braided tape is a strip structure woven from high thermal conductivity metal wires (such as copper or aluminum wires). Its function is to utilize the high thermal conductivity of the metal braided structure to efficiently transfer cold to the support 41, maintaining the sample's extremely low temperature. Furthermore, the inherent flexibility of the braided structure effectively absorbs and attenuates minute mechanical vibrations from refrigerant flow or external refrigerators, preventing these vibrations from being directly transmitted to the sample, thus providing an ultra-low vibration stable observation environment for atomic-level high-resolution imaging.

[0052] like Figure 6 As shown, this application further proposes that the in-situ ultra-low temperature sample rod for adapting standard sample transmission electron microscopy also includes a clamping assembly 6. The clamping assembly 6 includes a mounting frame 61, a lower insulation member 62, and an upper insulation member 63. One end of the mounting frame 61 is connected to the rod body 1, and a support base 611 is provided at the end of the mounting frame 61 away from the rod body 1. The lower insulation member 62 is placed on the support base 611, and the support member 41 is placed on the lower insulation member 62. The upper insulation member 63 covers the support member 41 and is connected to the lower insulation member 62. The upper insulation member 63 and / or the lower insulation member 62 have a clearance opening 621, and the flexible cooling conductor 4 is disposed through the clearance opening 621.

[0053] Specifically, the clamping assembly 6 is a mechanical structure used to fix, support, and protect the sample, and provide thermal insulation. The clamping assembly 6 can be assembled from multiple independent components, such as by fixing the mounting frame 61, upper insulation 63, and lower insulation 62 together using screws, clips, or welding. The mounting frame 61, as the main structure of the clamping assembly 6, provides mechanical connections and a support base 611. The support base 611 is a seat structure on the mounting frame 61 used to support the lower insulation 62. Specifically, the support base 611 has a placement groove for placing the lower insulation 62, the support member 41, the sample, and the upper insulation 63. The upper insulation 63 and the lower insulation 62 can be made of low thermal conductivity materials, such as polyetheretherketone, polytetrafluoroethylene, and polyimide, and their shape can be a cavity structure to further reduce heat conduction. The support member 41 can be in a ring shape to more securely fix a standard diameter 3mm sample, and the electron beam can pass through the sample and the inner ring of the ring-shaped support member 41. The upper insulation member 63 covers the support member 41 and connects with the lower insulation member 62 to form a closed insulation space. The clearance opening 621 is an opening reserved on the upper insulation member 63 and the lower insulation member 62 for the flexible heat-conducting member 4. The clearance opening 621 can be a circular or rectangular hole, and its size is slightly larger than the cross-section of the flexible heat-conducting member 4 to allow the flexible heat-conducting member 4 to pass through.

[0054] Through the above technical solution, this application introduces a clamping component 6, with the mounting frame 61 serving as the basic support structure. The support base 611 provides a stable physical reference for subsequent insulation and clamping components. The lower insulation component 62, placed on the support base 611, not only supports the support component 41 but, more importantly, utilizes its low thermal conductivity to effectively block the heat flow path from the rod body 1 and support base 611 to the support component 41, thereby ensuring the stability of the low-temperature environment in the sample area. The support component 41, placed on the lower insulation component 62, achieves thermal isolation between the sample and the support structure. The connection between the upper insulation component 63 and the lower insulation component 62 forms a closed microenvironment, enclosing the support component 41 and the sample, further reducing the impact of external radiative and convective heat transfer on the sample. By opening a clearance port 621 on the upper insulation component 63 or the lower insulation component 62, the flexible cooling component 4 can pass through this structure and connect to the support component 41, reducing cold leakage and ensuring that the cold energy can be efficiently and concentratedly applied to the sample. It should be noted that the support base 611, the lower insulation component 62, the support component 41 and the upper insulation component 63 are all provided with corresponding through holes to allow the electron beam to pass through.

[0055] This application further proposes that the clamping assembly 6 also includes a protective cover 64, which is provided with a plurality of protective feet that surround and support the periphery of the support base 611 to prevent the sample from falling off.

[0056] Specifically, the protective cover 64 covers the area of ​​the support base 611, and the protective feet extend from the protective cover 64 for connection and positioning with the support base 611. Multiple protective feet encircle and support the periphery of the support base 611; for example, the protective feet can surround and abut against the periphery of the support base 611 from the outside, securing it through friction or preload. By adding the protective cover 64 and protective feet to the clamping assembly 6, physical protection against sample detachment is provided for the sample on the support member 41. The protective cover 64, as a covering structure, forms a physical barrier above the sample, effectively preventing the sample from detaching from the support member 41 due to inertia or vibration.

[0057] like Figure 5 and Figure 7 As shown, this application further proposes that the in-situ ultra-low temperature sample rod for the transmission electron microscope of the standard sample also includes a radiation shielding shell 7. The radiation shielding shell 7 is connected to the observation end of the rod body 1 and is covered by a flexible cooling component 4 and a support component 41. The radiation shielding shell 7 has a through hole 81, which corresponds to the support component 41.

[0058] Specifically, the radiation shielding shell 7 is a structure used to block thermal radiation, its main function being to reduce heat transfer from external heat sources to internal low-temperature regions. In practical applications, the radiation shielding shell 7 can be implemented in various ways. For example, a multi-layer radiation shielding structure can be used, composed of multiple thin-film materials (such as aluminized polyester film), with the layers maintained in a vacuum or low-pressure state, effectively reducing radiative heat transfer through reflection and low emissivity. Another approach is to use ceramic or composite materials with low-emissivity coatings to achieve good thermal shielding effects.

[0059] The radiation shielding shell 7 covers the flexible cooling component 4 and the support component 41, ensuring that the flexible cooling component 4 and the support component 41 (i.e., the sample area) are completely protected by the radiation shielding shell 7, thereby maximizing the thermal radiation blocking effect. Understandably, the internal space of the radiation shielding shell 7 will have sufficient gaps to avoid direct contact with the flexible cooling component 4 and the support component 41, thus reducing unnecessary heat conduction. The radiation shielding shell 7 has a through hole 81, which is positioned corresponding to the support component 41. Its core function is to allow the electron beam to irradiate the sample on the support component 41 for transmission electron microscopy observation.

[0060] like Figure 6 As shown, in one embodiment, a temperature sensor 411 is provided on the support 41, which monitors the actual temperature of the support 41 (i.e., the sample) in real time, providing accurate feedback for temperature control. The selection of the temperature sensor 411 can be based on the required accuracy and temperature range. For example, a platinum resistance temperature sensor 411 can be used, which has high accuracy and stability and is suitable for a wide temperature range. In extremely low temperature environments, a silicon diode temperature sensor 411 or a carbon glass resistance temperature sensor 411 has good sensitivity and linearity. The sensor can be directly fixed to the sample placement area of ​​the support 41 by means of thermally conductive adhesive, micro screws, or welding to ensure good thermal contact and accurate temperature measurement. Exemplarily, the measurement lead of the temperature sensor 411 is led out from inside the sample rod through a vacuum feedthrough to an external temperature control instrument. The external temperature control system adjusts the cooling power of the external closed-loop refrigeration system according to the real-time feedback signal of the temperature sensor 411 to achieve temperature control.

[0061] like Figure 2 As shown, this application further proposes that the in-situ ultra-low temperature sample rod for the transmission electron microscope of the standard sample also includes a vacuum sealing assembly 8. The vacuum sealing assembly 8 is located at the tail end of the sample rod body 1. The end of the U-shaped flow channel tube 2 away from the bent tube section 22 is connected to the external cooling system through the vacuum sealing assembly 8. That is, the ends of the input tube section 21 and the return tube section 23 away from the bent tube section 22 are connected to the external cooling system through the vacuum sealing assembly 8.

[0062] Specifically, the vacuum sealing assembly 8 is a device used to maintain a high vacuum level inside the sample rod. Its core function is to significantly reduce the cold loss from the U-shaped flow channel 2 to the outside under operating conditions, thereby improving refrigeration efficiency. The end of the U-shaped flow channel 2 away from the bend section 22 is connected to the external refrigeration system through the vacuum sealing assembly 8. This means that the port in the U-shaped flow channel 2 used for refrigerant circulation establishes a fluid passage with the external refrigeration equipment through the vacuum sealing assembly 8. Specifically, the port of the U-shaped flow channel 2 can be connected to the internal channel of the vacuum sealing assembly 8, while the exterior of the vacuum sealing assembly 8 provides a standard interface for connection to the piping of the external refrigeration system.

[0063] Finally, it should be noted that the above embodiments are only for illustrating the present invention and not for limiting the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should all be covered within the protection scope of the present invention.

Claims

1. A sample holder for in-situ ultra-low temperature transmission electron microscopy of standard samples, characterized in that, include: The rod body has an internal mounting cavity, and the front end of the rod body is the observation end; The U-shaped flow channel tube is inserted into the mounting cavity. The U-shaped flow channel tube includes an input pipe section, a bent pipe section and a return pipe section connected in sequence. The bent pipe section is adjacent to the observation end. The U-shaped flow channel tube is used to transport refrigerant. A cooling-conducting connector is connected to the outside of the bent pipe section; A flexible cooling conductor, one end of which is connected to the cooling connector, and the other end extends outward from the mounting cavity and is provided with a support member for placing a sample.

2. The in-situ cryogenic sample holder for transmission electron microscopy of adapted standard samples according to claim 1, characterized in that, The cooling connector includes: The first component has a first U-shaped groove at one end; The second part has a second U-shaped groove at one end. The second part is connected to the first part. The first U-shaped groove and the second U-shaped groove are correspondingly arranged to form a U-shaped channel to accommodate the bent pipe section. The end is connected between the first component and the second component, and the end is connected to one end of the flexible cooling component.

3. The in-situ ultra-low temperature sample holder for transmission electron microscopy of adapted standard samples according to claim 2, characterized in that, The first split body has a first T-shaped groove at the end away from the first U-shaped groove, and the second split body has a second T-shaped groove at the end away from the second U-shaped groove. The first T-shaped groove and the second T-shaped groove are arranged correspondingly to form a snap-fit ​​groove, and the end is snapped into the snap-fit ​​groove.

4. The in-situ cryogenic sample holder for transmission electron microscopy of adapted standard samples according to claim 1, characterized in that, It also includes a thermal insulation support, which is sleeved on the outside of the U-shaped flow channel pipe and supported on the inner wall of the mounting cavity.

5. The in-situ cryogenic sample holder for transmission electron microscopy of adapted standard samples according to claim 4, characterized in that, The thermal insulation support includes: A support ring, the outer wall of which is supported by the inner wall of the mounting cavity; The first protrusion is disposed within the support ring; The second protrusion is located inside the support ring and is positioned opposite to the first protrusion. Both the input pipe section and the return pipe section pass through the support ring and abut against the first protrusion and the second protrusion.

6. The in-situ ultra-low temperature sample holder for transmission electron microscopy of adapted standard samples according to claim 1, characterized in that, The U-shaped flow channel is made of non-magnetic material; The cooling connector is a heat-conducting metal block; And / or, the flexible cooling component is a thermally conductive metal braided strip.

7. The in-situ cryogenic sample holder for transmission electron microscopy of adapted standard samples according to claim 1, characterized in that, It also includes a clamping assembly, the clamping assembly comprising: Mounting frame, one end of which is connected to the rod body, and a support base is provided at the end of the mounting frame away from the rod body; The lower insulation component is placed on the support base, and the support component is placed on the lower insulation component; An upper heat insulation component covers the support component and is connected to the lower heat insulation component. The upper heat insulation component and / or the lower heat insulation component are provided with a clearance opening, and the flexible heat-conducting component is disposed through the clearance opening.

8. The in-situ cryogenic sample holder for transmission electron microscopy of adapted standard samples according to claim 7, characterized in that, The clamping assembly also includes a protective cover, which has multiple protective feet that surround and support the periphery of the support base.

9. The in-situ cryogenic sample holder for transmission electron microscopy of adapted standard samples according to any one of claims 1 to 8, characterized in that, It also includes a radiation shielding shell, which is connected to the observation end of the rod body and covers the flexible cooling component and the support component. The radiation shielding shell has a through hole, which is provided corresponding to the support component. And / or, the support is provided with a temperature sensor.

10. The in-situ cryogenic sample holder for transmission electron microscopy of adapted standard samples according to any one of claims 1 to 8, characterized in that, It also includes a vacuum sealing assembly, which is located at the tail end of the sample rod body, and the end of the U-shaped flow channel tube away from the bent tube section is connected to an external cooling system through the vacuum sealing assembly.

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