A detachable two-dimensional fine adjustment faraday cup device

Abstract

This invention discloses a detachable two-dimensional fine-tuning Faraday cup device, comprising: an X-axis adjustment component, a Y-axis adjustment component, a Faraday cup component, a fixed base, and a slider. The fixed base is connected to the housing of a transmission electron microscope (TEM). The slider is disposed inside the fixed base. One end of the X-axis adjustment component is located outside the fixed base, and the other end passes through the fixed base and the slider sequentially, and is detachably connected to the Faraday cup component within the electron beam channel, for moving the Faraday cup component along the X-axis. One end of the Y-axis adjustment component is located outside the fixed base, and the other end passes through the fixed base and the slider sequentially, and abuts against the side of the X-axis adjustment component, for moving the Faraday cup component along the Y-axis. This invention features a compact structure, convenient operation, and high reliability, simultaneously achieving precise fine-tuning of the axial advance / retreat and radial position of the Faraday cup, making it particularly suitable for high-end vacuum electron optical equipment such as TEMs, which have stringent requirements for cavity space and operational reliability.

Description

Technical Field

[0001] This invention relates to the field of transmission electron microscopy equipment technology, and more specifically to a detachable two-dimensional fine-tuning Faraday cup device. Background Technology

[0002] As a core analytical tool in the field of nanotechnology, the imaging quality of a transmission electron microscope (TEM) directly depends on the electron beam current intensity, beam spot stability, and optical path alignment accuracy. In the daily debugging, sample analysis, and electron gun maintenance processes of TEM, staff need to use a Faraday cup to capture the electron beam, perform beam current adjustment and alignment, and acquire beam current signals. This is to complete key operations such as electron gun emission performance calibration, condenser lens optical path alignment, and beam drift monitoring. The Faraday cup is a core beam current detection component of the electron beam equipment, mainly used for acquiring beam current intensity, calibrating the beam spot center, calibrating ion implantation dose, and verifying electron beam emission stability; it is an essential component of the equipment.

[0003] Currently, commercial and self-developed charged particle beam equipment typically employs a single, fixed Faraday cup installation structure. The Faraday cup base is secured to a pre-set position within the equipment using bolts and welding, making the structure immovable and non-removable. Electron beams are highly susceptible to slight deviations due to electromagnetic lens temperature drift, mechanical vibration, and high-voltage power supply fluctuations. In such cases, the Faraday cup cannot be directly moved to match the beam spot; instead, the optical path must be repeatedly adjusted using multiple stages of the condenser lens's electromagnetic coils. If the beam center cannot be accurately aligned after the deviation, it directly leads to distorted beam acquisition data and failure of process calibration, necessitating shutdown and disassembly to adjust the entire optical path assembly, resulting in extremely high debugging costs. Furthermore, the permanent fixation of the Faraday cup within the equipment occupies already limited internal space, restricting the working range of other components and samples, significantly reducing the effective space utilization of the equipment. For example, in a transmission electron microscope (TEM), the electron beam must pass through eight magnetic lenses and three deflection coils sequentially from top to bottom, making optical path alignment extremely difficult. To perform segmented beam calibration, four Faraday cups are typically arranged along the beam path within the optical path. The first three sets are only used during factory commissioning and optical path maintenance to assist in segmented alignment. Only the Faraday cup at the end, installed inside the fluorescence cavity, serves as a permanent detection component, handling daily real-time beam intensity monitoring. Therefore, the first two Faraday cups must be detachable and quick to install and remove. After commissioning, they can be directly removed from the cavity, freeing up limited installation space within the cavity, avoiding obstruction of the sample stage travel and fluorescence imaging field of view by fixed fixtures, and eliminating electron beam scattering interference caused by idle cups, thus improving the imaging and detection accuracy of the equipment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a detachable two-dimensional fine-tuning Faraday cup device that is compact, easy to assemble and disassemble, and has high adjustment accuracy, in order to overcome the shortcomings of the prior art.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A detachable two-dimensional fine-tuning Faraday cup device includes: an X-axis adjustment component, a Y-axis adjustment component, a Faraday cup assembly, a fixed base, and a slider. The fixed base is connected to the housing of a transmission electron microscope (TEM). The slider is disposed inside the fixed base. One end of the X-axis adjustment component is located outside the fixed base, and the other end of the X-axis adjustment component passes through the fixed base and the slider sequentially, and is detachably connected to the Faraday cup assembly. The Faraday cup assembly is located within the electron beam channel of the TEM. The X-axis adjustment component is used to move the Faraday cup assembly along the X-direction within the electron beam channel. One end of the Y-axis adjustment component is located outside the fixed base, and the other end of the Y-axis adjustment component passes through the fixed base and the slider sequentially, and abuts against the side of the X-axis adjustment component. The Y-axis adjustment component is used to move the Faraday cup assembly along the Y-direction within the electron beam channel.

[0006] As a further improvement of the present invention, the X-direction adjustment assembly includes an X-direction knob and a feed shaft. The X-direction knob is located outside the fixed base, and one end of the feed shaft is located outside the fixed base and nested inside the X-direction knob. A bearing is provided between the X-direction knob and the feed shaft for transmission connection. The other end of the feed shaft passes through the fixed base and the slider in sequence and is detachably connected to the Faraday cup assembly. When the X-direction knob is turned, the feed shaft moves synchronously along the X-direction, thereby driving the Faraday cup assembly to move.

[0007] As a further improvement of the present invention, the X-axis adjustment assembly further includes a fixed axis, one end of which is located outside the fixed seat and nested inside the X-axis knob; the other end of the fixed axis passes through the fixed seat and the slider in sequence and is fixed inside the slider; the feed axis passes through the inner side of the fixed axis, and an elastic adjustment member is provided between the end of the feed axis and the end of the fixed axis, the elastic adjustment member being close to the Faraday cup assembly; the Y-axis adjustment assembly abuts against the side of the fixed axis.

[0008] As a further improvement of the present invention, the fixed shaft includes a first-order shaft cylinder, a second-order shaft cylinder and a third-order shaft cylinder with successively decreasing diameters. The first-order shaft cylinder is located outside the fixed seat, the second-order shaft cylinder is fixed inside the slider and the side of the second-order shaft cylinder abuts against the Y-axis adjustment component, and an elastic adjustment element is provided between the third-order shaft cylinder and the end of the feed shaft.

[0009] As a further improvement of the present invention, the side of the first-stage shaft cylinder is provided with a spiral guide groove along the circumferential direction; the side of the feed shaft is provided with a boss, the side of the X-direction knob is provided with a connecting hole, the connecting hole is provided with a movable pin, and the movable pin passes through the spiral guide groove and is connected to the boss; when the X-direction knob is turned, the movable pin drives the boss to move along the contour of the spiral guide groove, thereby realizing that the feed shaft drives the Faraday cup assembly to move along the X direction.

[0010] As a further improvement of the present invention, the Y-direction adjustment assembly includes a Y-direction knob, a pin, and two sets of elastic reset assemblies. The Y-direction knob is located on the outside of the fixed base, and the pin is located on the inside of the fixed base. One end of the pin is connected and fixed to the Y-direction knob, and the other end of the pin abuts against the side of the second-order shaft cylinder. The bottom of the slider contacts the lower part of the fixed base, and the two sets of elastic reset assemblies are fixed adjacently inside the fixed base. One set of elastic reset assemblies contacts the outer top of the slider, and the other set of elastic reset assemblies is opposite to the pin and contacts the outer side of the slider, so as to assist the slider in moving along the Y-direction within the fixed base. When the Y-direction knob is turned, the pin pushes the slider and the fixed shaft to move along the Y-direction, thereby enabling the feed shaft to drive the Faraday cup assembly to move along the Y-direction.

[0011] As a further improvement of the present invention, the second-stage shaft cylinder is provided with a limiting groove on its side, the end of the ejector pin abuts against one side of the limiting groove, and a flat key is provided on the other side of the limiting groove to limit the axial rotation of the fixed shaft.

[0012] As a further improvement of the present invention, the elastic reset component includes a fixed block, a movable block and a spring sheet; one side of the fixed block is provided with a plurality of mounting holes to realize the connection and fixation of the fixed block and the fixed seat, the other side of the fixed block is provided with a limiting step, one end of the movable block is open and slidably nested on the limiting step, a spring sheet is provided between the fixed block and the movable block, and the movable block is in contact with the slider.

[0013] As a further improvement of the present invention, one end of the feed shaft is provided with a threaded interface, the threaded interface including an internal thread and an external thread, the internal thread of the threaded interface is detachably connected to the Faraday cup assembly, the external thread of the threaded interface is detachably connected to the retaining ring, one end of the elastic adjusting member abuts against the end of the second-stage shaft cylinder, the other end of the elastic adjusting member abuts against the retaining ring, and the elastic adjusting member is nested on the outer circumference of the third-stage shaft cylinder; the other end of the feed shaft is provided with a limiting ring, and the bearing is nested and connected to the limiting ring.

[0014] As a further improvement of the present invention, the Faraday cup assembly includes a connector and a Faraday cup. One end of the connector is detachably connected to the Faraday cup via a fastener, and the other end of the connector is detachably connected to a threaded interface via an external thread. A sealing ring is provided on the end of the connector and the inner side of the threaded interface. The connector is provided with a through wire hole. One end of the wire is connected to the Faraday cup, and the other end of the wire passes through the wire hole and extends to the outside via the inner hole of the feed shaft to realize electrical signal transmission.

[0015] Compared with the prior art, the advantages of the present invention are as follows: The detachable two-dimensional fine-tuning Faraday cup device of this invention achieves two-dimensional high-precision in-situ fine-tuning of the Faraday cup within the electron beam channel of the vacuum chamber through an X-axis transmission structure with a spiral guide groove and a moving block, and a Y-axis adjustment structure with a pin and an elastic reset component. This solves the problems of low adjustment accuracy and easy drift of traditional mechanisms. The detachable connection design allows the Faraday cup to be immediately removed after centering and calibration, completely freeing up the internal space of the chamber and avoiding the obstruction of the sample stage travel and imaging field of view by fixed fixtures. At the same time, it eliminates the scattering interference of the idle cup to the electron beam, significantly improving the imaging quality and beam detection accuracy of the transmission electron microscope. Through the vacuum-sealed wiring structure integrated inside the feed shaft, stable transmission of electrical signals is achieved while ensuring high vacuum sealing performance, which well meets the stringent requirements of high-end vacuum electron optical equipment for compact space and operational reliability. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the principle of a quarter-section of the detachable two-dimensional fine-tuning Faraday cup device in a specific embodiment of the present invention; Figure 2 This is a schematic diagram of the half-section structure of the detachable two-dimensional fine-tuning Faraday cup device in a specific embodiment of the present invention; Figure 3 This is a partial cross-sectional structural schematic diagram of the detachable two-dimensional fine-tuning Faraday cup device in a specific embodiment of the present invention; Figure 4 This is a schematic diagram illustrating the overall structural principle of the detachable two-dimensional fine-tuning Faraday cup device in a specific embodiment of the present invention. Figure 5 This is a side view schematic diagram of the detachable two-dimensional fine-tuning Faraday cup device in a specific embodiment of the present invention; Figure 6 This is a schematic diagram of the structural principle of the fixed axis in a specific embodiment of the present invention; Figure 7 This is a schematic diagram illustrating the structural principle of the feed shaft in a specific embodiment of the present invention; Figure 8 This is a schematic diagram of the overall structure of the reset component in a specific embodiment of the present invention; Figure 9 This is a schematic diagram of the partial structure of the reset component in a specific embodiment of the present invention.

[0017] Legend: 1. X-direction knob; 2. Feed axis; 201. Limit ring; 202. Boss; 203. Threaded interface; 204. Keyway; 3. Bearing; 4. Fixed seat; 5. Y-direction knob; 6. Ejector pin; 7. Flat key; 8. Slider; 9. Elastic adjustment component; 10. Sealing ring; 11. Connecting component; 12. Faraday cup; 13. Wire hole; 14. Elastic reset component; 141. Fixed block; 142. Moving block; 143. Spring plate; 144. Mounting hole; 145. Limit step; 15. Pin; 16. Moving pin; 17. Fastening screw; 18. Fixed shaft; 181. First-stage shaft sleeve; 182. Second-stage shaft sleeve; 183. Third-stage shaft sleeve; 184. Spiral guide groove; 185. Limit groove; 19. Retaining ring. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0019] In the description of this invention, it should be understood that the terms "side", "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and are not intended to 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 of this invention.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more unless otherwise explicitly specified.

[0021] Example like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the detachable two-dimensional fine-tuning Faraday cup device of the present invention includes an X-axis adjustment component, a Y-axis adjustment component, a Faraday cup component, a fixed base 4, and a slider 8. The fixed base 4 serves as the mounting reference for the entire device and is connected and fixed to the housing of the transmission electron microscope. Simultaneously, a pin 15 is provided on the fixed base 4 to facilitate quick positioning of the fixed base 4 and the housing of the transmission electron microscope. The slider 8 is disposed inside the fixed base 4, serving as a support for Y-axis movement; its outer contour is adapted to the inner cavity of the fixed base 4, allowing it to slide directionally within the space defined by the fixed base 4.

[0022] One end of the X-axis adjustment assembly is located outside the fixed base 4, facilitating manual adjustment by the operator outside the vacuum chamber. The other end of the X-axis adjustment assembly passes through the fixed base 4 and the slider 8 in sequence, and is detachably connected to the Faraday cup assembly. The Faraday cup assembly is located within the electron beam channel of the transmission electron microscope and is used to receive and detect the electron beam signal. When the beam spot position needs to be adjusted, the X-axis adjustment assembly moves the Faraday cup assembly along the X-axis within the electron beam channel, achieving axial approach or departure from the centering position.

[0023] One end of the Y-axis adjustment component is also located outside the fixed base 4, and the other end of the Y-axis adjustment component passes through the fixed base 4 and the slider 8 in sequence, and abuts against the side of the X-axis adjustment component. In this embodiment, the Y-axis adjustment component does not directly act on the Faraday cup assembly, but indirectly drives the entire X-axis transmission chain and the Faraday cup assembly at the end to move along the Y direction by pushing the side wall of the X-axis adjustment component. Through the force transmission path design of the side abutment, the Y-axis adjustment and the X-axis adjustment are orthogonal to each other in space, and independent yet interconnected in terms of mechanical transmission. Specifically, when the Y-axis adjustment component is turned or pushed, the thrust generated acts on the side of the X-axis adjustment component. Since there is a constraint relationship between the X-axis adjustment component and the slider 8, this thrust is ultimately converted into the Y-axis translation of the slider 8 together with the X-axis adjustment component and the Faraday cup assembly within the fixed base 4.

[0024] Through the above architecture, this embodiment establishes independent X-axis and Y-axis adjustment degrees of freedom. The X-axis adjustment component is responsible for axial feed, and the Y-axis adjustment component is responsible for radial offset. Together, they enable two-dimensional in-situ fine-tuning of the Faraday cup assembly within the electron beam channel. Furthermore, because the Faraday cup assembly and the X-axis adjustment component are detachably connected, and the entire adjustment mechanism is integrated into the mounting base 4, this device can provide high-precision beam alignment during the commissioning phase and can be quickly removed during the imaging phase. This solves the technical problems of traditional fixed Faraday cups occupying cavity space, obstructing sample stage travel, and causing electron beam scattering interference.

[0025] like Figure 1 and Figure 3As shown, the X-direction adjustment assembly includes an X-direction knob 1 and a feed shaft 2. The X-direction knob 1 is located outside the fixed base 4. One end of the feed shaft 2 is located outside the fixed base 4 and nested inside the X-direction knob 1. A bearing 3 is provided between the X-direction knob 1 and the feed shaft 2 for transmission connection. The other end of the feed shaft 2 passes through the fixed base 4 and the slider 8 in sequence and is detachably connected to the Faraday cup assembly.

[0026] Specifically, bearing 3 is preferably a thrust bearing or a deep groove ball bearing. Its outer ring abuts against the X-direction knob 1, and its inner ring abuts against the end of the feed shaft 2, thereby establishing a decoupling relationship between the rotational and axial degrees of freedom. When the operator turns the X-direction knob 1, the rotational motion is converted into an axial thrust or pull force on the feed shaft 2 through the bearing 3, causing the feed shaft 2 to move synchronously along the X-direction, thereby driving the Faraday cup assembly to move, while the feed shaft 2 itself does not rotate around its axis.

[0027] Furthermore, the X-axis adjustment assembly also includes a fixed axis 18. One end of the fixed axis 18 is located outside the fixed base 4 and nested inside the X-axis knob 1. The other end of the fixed axis 18 passes through the fixed base 4 and the slider 8 in sequence and is fixed inside the slider 8. The feed axis 2 passes through the inside of the fixed axis 18, and an elastic adjustment member 9 is provided between the end of the feed axis 2 and the end of the fixed axis 18. The elastic adjustment member 9 is close to the Faraday cup assembly. Figure 1 and Figure 6 As can be seen, the fixed shaft 18 serves as a stationary guide reference, and its outer diameter forms a precise sliding fit with the inner hole of the feed shaft 2, restricting the feed shaft 2's degrees of freedom except for axial translation. The elastic adjustment element 9 can specifically be a compression spring; in other embodiments, a disc spring assembly or a wave spring can also be used. It is compressed and positioned between the end of the feed shaft 2 and the end of the fixed shaft 18, generating a continuous axial preload. This preload has a dual function: firstly, it eliminates the assembly gap between the feed shaft 2 and the fixed shaft 18 caused by machining tolerances, ensuring the motion rigidity and return accuracy during the X-axis feed process, allowing minute knob angle changes to be instantly converted into the displacement response of the Faraday cup assembly; secondly, since the fixed shaft 18 is fixed on the slider 8, the axial support force provided by the elastic adjustment element 9 also provides a stable force fulcrum for the Y-axis adjustment. When the Y-axis adjustment assembly pushes the side wall of the fixed shaft 18, the entire X-axis transmission chain can move smoothly as a whole, avoiding Y-axis adjustment lag or jamming caused by internal loosening. In addition, placing the elastic adjustment element 9 on the side close to the Faraday cup assembly helps to shorten the force transmission path, reduce bending deformation caused by the cantilever beam effect, and further improve the dynamic stability of the device in the vacuum chamber.

[0028] like Figure 2 and Figure 6As shown, the fixed shaft 18 includes a first-order shaft cylinder 181, a second-order shaft cylinder 182, and a third-order shaft cylinder 183 with decreasing diameters. The first-order shaft cylinder 181 is located outside the fixed seat 4, the second-order shaft cylinder 182 is fixed inside the slider 8, and the side of the second-order shaft cylinder 182 abuts against the Y-axis adjustment component. An elastic adjustment element 9 is provided between the third-order shaft cylinder 183 and the end of the feed shaft 2. Specifically, the first-order shaft cylinder 181 serves as the external operating area and precision transmission carrier, and its outer cylindrical surface is machined with a spiral guide groove 184, which directly participates in the conversion of X-axis motion. The second-order shaft cylinder 182 serves as an intermediate transition section, which not only forms a rigid connection with the slider 8 through interference fit or screw fastening, becoming the direct bearing surface of the Y-axis adjustment force, but also provides a radial support reference for the entire fixed shaft 18, ensuring its coaxiality during the movement of the slider 8. The third-order shaft cylinder 183 has the smallest diameter and mainly serves as the inner guide mandrel of the elastic adjustment element 9, preventing the elastic adjustment element 9 from buckling and becoming unstable during compression.

[0029] like Figure 6 As shown, the side of the first-order shaft cylinder 181 is provided with a helical guide groove 184 along the circumferential direction; as Figure 7 As shown, a boss 202 is provided on the side of the feed shaft 2. Correspondingly, a connecting hole is provided on the side of the X-direction knob 1. A movable pin 16 is provided in the connecting hole, and the movable pin 16 passes through the spiral guide groove 184 and connects to the boss 202. When the X-direction knob 1 is turned, the movable pin 16 drives the boss 202 to move along the contour of the spiral guide groove 184, thereby realizing that the feed shaft 2 drives the Faraday cup assembly to move in the X direction.

[0030] In this embodiment, the movable pin 16 is preferably made of a wear-resistant, low-friction coefficient non-magnetic material, such as ceramic, to avoid magnetic interference with the electron beam of the transmission electron microscope. The movable pin 16 is embedded in the connecting hole of the X-direction knob 1 and passes through the spiral guide groove 184 on the first-order shaft cylinder 181, forming a rigid connection with the boss 202 on the outer wall of the feed shaft 2, for example, through press fitting or threaded fastening, thereby forcibly coupling the rotational movement of the X-direction knob 1 to the axial translation of the feed shaft 2. The geometric parameters of the spiral guide groove 184 directly determine the adjustment performance: its helix angle is inversely proportional to the feed resolution; a smaller helix angle can obtain higher displacement sensitivity, suitable for nanoscale beam spot alignment; simultaneously, when the helix angle of the spiral guide groove 184 is less than the friction angle, the mechanism has a self-locking characteristic, that is, after the external driving torque is removed, the axial position of the feed shaft 2 can be maintained by the static friction between the contact surfaces, effectively preventing accidental drift of the Faraday cup assembly caused by the device's own weight, vacuum chamber vibration, or residual stress of the elastic adjustment component 9. Furthermore, as Figure 1 and Figure 4As shown, a through fastening screw 17 is provided on the side of the X-direction knob 1. When the Faraday cup assembly receives the signal and completes the alignment, the fastening screw 17 is tightened to abut against the outer wall of the first-stage shaft 181 to fix the X-direction knob 1 to the fixed shaft 18 and prevent drift.

[0031] In this embodiment, the Y-direction adjustment assembly includes a Y-direction knob 5, a pin 6, and two sets of elastic reset assemblies 14. The Y-direction knob 5 is located on the outside of the fixed base 4, and the pin 6 is located on the inside of the fixed base 4. One end of the pin 6 is connected and fixed to the Y-direction knob 5, and the other end of the pin 6 abuts against the side of the second-order shaft cylinder 182. Specifically, as... Figure 1 , Figure 2 and Figure 5 As shown, the Y-direction knob 5 is rigidly connected to the ejector pin 6 via a threaded pair or interference fit. When the operator turns the Y-direction knob 5, the ejector pin 6 undergoes axial displacement along its own axis, which directly acts on the side wall surface of the second-order shaft cylinder 182. Since the second-order shaft cylinder 182 is fixed inside the slider 8, the thrust applied by the ejector pin 6 is ultimately converted into the translational movement of the slider 8, together with the fixed shaft 18 and the entire X-direction transmission chain, along the Y-direction within the fixed seat 4.

[0032] like Figure 5 As shown, the bottom of the slider 8 contacts the lower part of the fixed base 4. Two sets of elastic reset components 14 are fixed adjacently inside the fixed base 4. One set of elastic reset components 14 contacts the outer top of the slider 8, and the other set of elastic reset components 14 is opposite to the ejector pin 6 and contacts the outer side of the slider 8, in order to assist the slider 8 in moving along the Y direction within the fixed base 4. Specifically, the two sets of elastic reset components 14 are arranged orthogonally or approximately orthogonally in space, each undertaking different mechanical functions. The elastic reset component 14 that contacts the outer top of the slider 8 mainly provides a reverse restoring force perpendicular to the Y-direction of movement. When the ejector pin 6 pushes the slider 8 to move to one side, this set of components is compressed and stores energy. Once the external force is removed or the Y-direction knob 5 is turned in the opposite direction, the stored elastic potential energy drives the slider 8 back to its original position, realizing the bidirectional adjustment capability in the Y direction. The elastic reset component 14, which contacts the outer side of the slider 8, provides a lateral clamping force parallel to the Y-direction of movement, continuously pressing the slider 8 against the guide reference surface at the bottom of the fixed seat 4, thereby eliminating the fit clearance between the slider 8 and the fixed seat 4 caused by machining tolerances or wear. The two sets of elastic reset components 14 work together to form a gapless Y-direction push-pull adjustment system, which not only ensures the smoothness and linearity of the slider 8's movement in the Y-direction within the fixed seat 4, but also significantly improves the repeatability and positioning accuracy.

[0033] When the Y-direction knob 5 is turned, the ejector pin 6 pushes the slider 8 and the fixed shaft 18 to move along the Y-direction, thereby enabling the feed shaft 2 to drive the Faraday cup assembly to move along the Y-direction. In this embodiment, the Y-direction adjustment force is transmitted only through the lateral contact between the ejector pin 6 and the second-order shaft cylinder 182, and is independent of the helical guide groove 184 and the elastic adjustment element 9 inside the X-direction transmission chain in terms of mechanical path. Even if a small lateral component force is generated during the Y-direction adjustment process, it will not affect the accuracy and self-locking stability of the X-direction feed, truly achieving complete decoupling of the two-dimensional adjustment motion.

[0034] like Figure 6 As shown, the second-order shaft cylinder 182 has a limiting groove 185 on its side. The end of the ejector pin 6 abuts against one side of the limiting groove 185, and a flat key 7 is provided on the other side of the limiting groove 185 to limit the axial rotation of the fixed shaft 18. Specifically, the limiting groove 185 extends axially along the second-order shaft cylinder 182, and its width is slightly larger than the diameter of the end of the ejector pin 6, forming a guide space to accommodate the end of the ejector pin 6. The flat key 7 is fixed at the corresponding position inside the slider 8 and is embedded in the wall of the limiting groove 185 opposite to the ejector pin 6, thus forming a circumferential clamping constraint on the second-order shaft cylinder 182 together with the ejector pin 6. When the Y-direction knob 5 drives the ejector pin 6 to push the second-order shaft cylinder 182 to translate along the Y direction, the ejector pin 6 and the flat key 7 respectively abut against the two side walls of the limiting groove 185, converting the Y-direction thrust into pure linear motion. At the same time, it strictly restricts the rotational freedom of the fixed shaft 18 around its own axis and prevents the X-direction and Y-direction adjustments from coupling. If the fixed shaft 18 rotates slightly during the Y-direction movement, the phase of the spiral guide groove 184 on the first-order shaft cylinder 181 will change accordingly, causing the feed shaft 2 and the Faraday cup assembly to produce unexpected additional displacement in the X direction, seriously damaging the orthogonality and accuracy of the two-dimensional fine adjustment. Through the cooperation of the limiting groove 185 and the flat key 7, not only is this parasitic motion eliminated, but the flat key 7 also shares the overturning moment that may be generated by the eccentric thrust of the ejector pin 6, protecting the precision mating surface of the spiral guide groove 184 and the moving pin 16 from abnormal wear. It should be understood that the cross-sectional shape of the limiting groove 185 is not limited to the rectangle shown in the figure. In other embodiments, a V-shaped groove, a dovetail groove, or an arc groove may also be used, as long as it can cooperate with the flat key 7 and the ejector pin 6 to achieve the dual functions of circumferential limiting and axial guiding. The flat key 7 may also be replaced with a pin, a rib, or other equivalent anti-rotation element.

[0035] In this embodiment, the elastic reset assembly 14 includes a fixed block 141, a movable block 142, and a spring sheet 143. The fixed block 141 has multiple mounting holes 144 on one side to connect and fix the fixed block 141 to the fixed base 4. A limiting step 145 is provided on the other side of the fixed block 141. One end of the movable block 142 is open and slidably nested on the limiting step 145. A spring sheet 143 is provided between the fixed block 141 and the movable block 142, and the movable block 142 contacts the slider 8.

[0036] like Figure 5 , Figure 8 and Figure 9 As shown, the fixed block 141 is securely mounted on the inner wall of the fixed base 4 through three mounting holes 144 to prevent it from deflecting during repeated stress. The limiting step 145 provides precise linear sliding guidance for the moving block 142, ensuring that the moving block 142 can only extend and retract in a direction perpendicular to the surface of the slider 8, avoiding interference of the lateral component of the restoring force with the linearity of the Y-axis movement. The spring plate 143 is preferably made of non-magnetic elastic materials such as beryllium bronze, titanium alloy, or low-permeability stainless steel. After pre-compression, it is placed between the fixed block 141 and the moving block 142 to provide a continuous and stable restoring force. In addition, the contact surface between the moving block 142 and the slider 8 can be further provided with wear-resistant pads or polished to reduce contact stress and extend service life.

[0037] In this embodiment, one end of the feed shaft 2 is provided with a threaded interface 203, which includes internal and external threads. The internal thread of the threaded interface 203 is detachably connected to the Faraday cup assembly, and the external thread of the threaded interface 203 is detachably connected to the retaining ring 19. One end of the elastic adjusting member 9 abuts against the end of the second-stage shaft cylinder 182, and the other end of the elastic adjusting member 9 abuts against the retaining ring 19. The elastic adjusting member 9 is nested on the outer periphery of the third-stage shaft cylinder 183. The other end of the feed shaft 2 is provided with a limiting ring 201 and a keyway 204. The bearing 3 is nested with the limiting ring 201, and the keyway 204 is located to ensure that the Faraday cup assembly is horizontal. Specifically, as shown... Figure 2 , Figure 4 and Figure 7 As shown, the threaded interface 203 serves as the integrated interface carrier at the end of the X-axis drive chain. Its internal thread is used to enable quick engagement and disengagement with the Faraday cup assembly, while the external thread is used to fix the retaining ring 19, thereby axially limiting the elastic adjustment member 9 to the outer circumference of the third-order shaft cylinder 183. The elastic adjustment member 9 is compressed between the end of the second-order shaft cylinder 182 and the retaining ring 19, forming a closed preload transmission loop. This preload not only eliminates the axial clearance between the feed shaft 2 and the fixed shaft 18, but also transforms into an axial clamping force on the Faraday cup assembly through the threaded connection between the retaining ring 19 and the threaded interface 203, ensuring that it remains firmly connected even when subjected to vibration or thermal deformation within the vacuum chamber of the transmission electron microscope. The limiting ring 201 is located at the end of the feed shaft 2 away from the Faraday cup assembly, forming an axial positioning fit with the inner ring of the bearing 3 to prevent axial movement of the bearing 3 during repeated push-pull processes, thereby ensuring the coaxiality and smoothness of the X-axis drive chain. It should be understood that the internal and external threads of the threaded interface 203 can be designed with different pitches. For example, the internal thread can be made of fine thread to improve connection accuracy and self-locking, while the external thread can be made of coarse thread to enhance tensile strength and disassembly efficiency. The retaining ring 19 can also be replaced by a snap ring, a pressure cap or other equivalent axial limiting element, as long as it can reliably press the elastic adjustment element 9.

[0038] Furthermore, the Faraday cup assembly includes a connector 11 and a Faraday cup 12. One end of the connector 11 is detachably connected to the Faraday cup 12 via a fastener, and the other end of the connector 11 is detachably connected to a threaded interface 203 via an external thread. A sealing ring 10 is provided on the end of the connector 11 and the inner side of the threaded interface 203. The connector 11 has a through wire hole 13. One end of the wire is connected to the Faraday cup 12, and the other end of the wire passes through the wire hole 13 and extends to the outside via the inner hole of the feed shaft 2 to achieve electrical signal transmission. Figure 1 , Figure 2 and Figure 3 As can be seen, the connector 11 serves as a transitional adapter between the Faraday cup 12 and the feed shaft 2. One end is rigidly connected to the Faraday cup 12 via a screw, facilitating the replacement of Faraday cups 12 of different specifications or materials according to testing requirements. The other end is screwed into the internal thread of the threaded interface 203 via an external thread, enabling quick assembly and disassembly of the entire Faraday cup assembly. The sealing ring 10 is preferably a vacuum-compatible sealing element such as a fluororubber O-ring or a polytetrafluoroethylene flat washer. It is compressed and positioned between the end face of the connector 11 and the inner stepped surface of the threaded interface 203, forming the first static vacuum sealing barrier, effectively preventing the communication between the atmosphere and the vacuum chamber. The wire hole 13 passes through the connector 11 axially. The wire is led out from the Faraday cup 12, passes through the wire hole 13, and then leads to the outside of the chamber through the hollow inner cavity of the feed shaft 2, avoiding the obstruction of the electron beam channel and interference with moving parts by the external wiring. Inside the wire hole 13, the annular gap between the wire and the hole wall is encapsulated and cured with materials such as epoxy resin, silicone rubber or ceramic-based sealant to form a second dynamic sealing barrier, which not only ensures airtightness in a high vacuum environment, but also provides mechanical support and insulation protection for the wire.

[0039] In actual use, the device of this embodiment is installed on the reserved interface of the vacuum cavity of the transmission electron microscope via the fixing base 4. The interface size is compatible with the standard aperture interface, so that the device can be used as a temporary replacement for the aperture in the electron beam channel.

[0040] The specific operating procedure includes the following steps: Step S1: Device Loading and Initial Positioning. When electron beam alignment and calibration are required, the operator first removes the original aperture of the transmission electron microscope from the vacuum chamber interface. Then, the detachable two-dimensional fine-tuning Faraday cup device provided in this embodiment is installed into the interface and sealed. At this time, the Faraday cup 12 is located within the electron beam channel and is in the initial position to be adjusted. Because a sealing ring 10 and a potting compound sealing structure are provided between the connector 11 and the feed shaft 2, the high vacuum environment of the chamber can be maintained after the device is installed, without the need for additional evacuation waiting time.

[0041] Step S2: Two-dimensional precision fine-tuning and signal optimization. The operator finely adjusts the spatial position of the Faraday cup 12 by rotating the X-direction knob 1 and the Y-direction knob 5 located on the outside of the fixed base 4. During the X-direction adjustment, the rotation of the X-direction knob 1 is converted into the axial displacement of the feed shaft 2 via the spiral guide groove 184, causing the Faraday cup 12 to approach or move away from the beam spot focal point along the electron beam axis. During the Y-direction adjustment, the Y-direction knob 5 drives the ejector pin 6 to push the slider 8 and the fixed axis 18, causing the Faraday cup 12 to translate in a plane perpendicular to the electron beam axis.

[0042] Step S3, State Locking. Once the beam alignment signal reaches its optimal and stable state, the operator tightens the fastening screw 17 to rigidly lock the relative position between the X-direction knob 1 and the fixed axis 18. This prevents the Faraday cup 12 from drifting due to equipment micro-vibration or gravitational creep, ensuring the absolute maintenance of the alignment state during calibration data reading and subsequent verification.

[0043] Step S4: Device Removal and Aperture Reset. After calibration, loosen the fastening screws 17 and the fasteners connecting the fixing seat 4 to the cavity interface, completely remove the entire Faraday cup assembly along with the adjustment mechanism from the vacuum cavity, and reinstall the original aperture. Since the Faraday cup assembly is connected to the feed shaft 2 via a threaded interface 203, if a different specification of Faraday cup 12 needs to be replaced, the connector 11 can be quickly unscrewed at this stage for modular replacement.

[0044] Compared to traditional Faraday cups fixed inside the cavity, this device only intervenes briefly when calibration is required and completely moves out of the field of view during non-detection periods. This completely frees up the sample stage's movement and imaging field of view, avoiding obstruction of the observation range by fixed fixtures. It also eliminates stray electron scattering sources generated by idle Faraday cups remaining near the electron beam channel for extended periods, thus significantly improving image contrast and signal-to-noise ratio in high-magnification imaging mode of the transmission electron microscope. Furthermore, the entire adjustment and disassembly process is completed while maintaining a vacuum seal. The wires are led out through the inner hole of feed shaft 2 and isolated by a double sealing barrier, ensuring the stability of beam signal transmission while avoiding damage to the vacuum environment from repeated disassembly and assembly. This fully meets the stringent requirements of high-precision, high-cleanliness, and ease of operation for high-end vacuum electron optical equipment. It should be understood that although this embodiment uses a transmission electron microscope as an example, this device is also applicable to scanning electron microscopes, electron beam exposure machines, ion implanters, or other electron optical equipment requiring beam detection and position fine-tuning in a vacuum environment, provided they have the corresponding installation interface and space conditions.

[0045] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A detachable two-dimensional fine-tuning Faraday cup device, characterized in that, include: The system comprises an X-axis adjustment component, a Y-axis adjustment component, a Faraday cup component, a fixed base (4), and a slider (8). The fixed base (4) is connected to the outer shell of the transmission electron microscope (TEM). The slider (8) is located inside the fixed base (4). One end of the X-axis adjustment component is located outside the fixed base (4). The other end of the X-axis adjustment component passes through the fixed base (4) and the slider (8) in sequence and is detachably connected to the Faraday cup component. The Faraday cup component is located in the electron beam channel of the TEM. The X-axis adjustment component is used to drive the Faraday cup component to move along the X direction in the electron beam channel. One end of the Y-axis adjustment component is located outside the fixed base (4). The other end of the Y-axis adjustment component passes through the fixed base (4) and the slider (8) in sequence and abuts against the side of the X-axis adjustment component. The Y-axis adjustment component is used to drive the Faraday cup component to move along the Y direction in the electron beam channel.

2. The detachable two-dimensional fine-tuning Faraday cup device according to claim 1, characterized in that, The X-direction adjustment assembly includes an X-direction knob (1) and a feed shaft (2). The X-direction knob (1) is located outside the fixed base (4). One end of the feed shaft (2) is located outside the fixed base (4) and nested inside the X-direction knob (1). A bearing (3) is provided between the X-direction knob (1) and the feed shaft (2) for transmission connection. The other end of the feed shaft (2) passes through the fixed base (4) and the slider (8) in sequence and is detachably connected to the Faraday cup assembly. When the X-direction knob (1) is turned, the feed shaft (2) moves synchronously along the X direction, thereby driving the Faraday cup assembly to move.

3. The detachable two-dimensional fine-tuning Faraday cup device according to claim 2, characterized in that, The X-axis adjustment assembly also includes a fixed axis (18), one end of which is located outside the fixed seat (4) and nested inside the X-axis knob (1); the other end of the fixed axis (18) passes through the fixed seat (4) and the slider (8) in sequence and is fixed inside the slider (8); the feed shaft (2) passes through the inside of the fixed axis (18), and an elastic adjustment member (9) is provided between the end of the feed shaft (2) and the end of the fixed axis (18); the elastic adjustment member (9) is close to the Faraday cup assembly; the Y-axis adjustment assembly abuts against the side of the fixed axis (18).

4. The detachable two-dimensional fine-tuning Faraday cup device according to claim 3, characterized in that, The fixed shaft (18) includes a first-order shaft cylinder (181), a second-order shaft cylinder (182), and a third-order shaft cylinder (183) with diameters decreasing sequentially. The first-order shaft cylinder (181) is located outside the fixed seat (4). The second-order shaft cylinder (182) is fixed inside the slider (8), and the side of the second-order shaft cylinder (182) abuts against the Y-axis adjustment component. An elastic adjustment component (9) is provided between the third-order shaft cylinder (183) and the end of the feed shaft (2).

5. The detachable two-dimensional fine-tuning Faraday cup device according to claim 4, characterized in that, The first-stage shaft cylinder (181) has a spiral guide groove (184) along the circumferential direction on its side; the feed shaft (2) has a boss (202) on its side; the X-direction knob (1) has a connecting hole on its side; a movable pin (16) is provided in the connecting hole; and the movable pin (16) passes through the spiral guide groove (184) and is connected to the boss (202); when the X-direction knob (1) is turned, the movable pin (16) drives the boss (202) to move along the contour of the spiral guide groove (184), thereby realizing that the feed shaft (2) drives the Faraday cup assembly to move along the X direction.

6. The detachable two-dimensional fine-tuning Faraday cup device according to claim 4, characterized in that, The Y-direction adjustment assembly includes a Y-direction knob (5), a pin (6), and two sets of elastic reset assemblies (14). The Y-direction knob (5) is located on the outside of the fixed base (4), and the pin (6) is located on the inside of the fixed base (4). One end of the pin (6) is connected and fixed to the Y-direction knob (5), and the other end of the pin (6) abuts against the side of the second-order shaft cylinder (182). The bottom of the slider (8) contacts the lower part of the fixed base (4), and the two sets of elastic reset assemblies (14) are fixed adjacent to each other on the fixed base. Inside the fixed seat (4), one set of elastic reset components (14) contacts the outer top of the slider (8), and another set of elastic reset components (14) is opposite to the ejector pin (6) and contacts the outer side of the slider (8) to assist the slider (8) in moving along the Y direction within the fixed seat (4); when the Y direction knob (5) is turned, the ejector pin (6) pushes the slider (8) and the fixed shaft (18) to move along the Y direction, thereby enabling the feed shaft (2) to drive the Faraday cup assembly to move along the Y direction.

7. The detachable two-dimensional fine-tuning Faraday cup device according to claim 6, characterized in that, The second-order shaft cylinder (182) is provided with a limiting groove (185) on its side. The end of the ejector pin (6) abuts against one side of the limiting groove (185). The other side of the limiting groove (185) is provided with a flat key (7) to limit the axial rotation of the fixed shaft (18).

8. The detachable two-dimensional fine-tuning Faraday cup device according to claim 6, characterized in that, The elastic reset assembly (14) includes a fixed block (141), a movable block (142), and a spring sheet (143). The fixed block (141) has multiple mounting holes (144) on one side to connect and fix the fixed block (141) to the fixed seat (4). The fixed block (141) has a limiting step (145) on the other side. One end of the movable block (142) is open and slides on the limiting step (145). A spring sheet (143) is provided between the fixed block (141) and the movable block (142). The movable block (142) is in contact with the slider (8).

9. The detachable two-dimensional fine-tuning Faraday cup device according to any one of claims 4 to 8, characterized in that, One end of the feed shaft (2) is provided with a threaded interface (203), which includes an internal thread and an external thread. The internal thread of the threaded interface (203) is detachably connected to the Faraday cup assembly, and the external thread of the threaded interface (203) is detachably connected to the retaining ring (19). One end of the elastic adjusting member (9) abuts against the end of the second-stage shaft cylinder (182), and the other end of the elastic adjusting member (9) abuts against the retaining ring (19). The elastic adjusting member (9) is nested on the outer periphery of the third-stage shaft cylinder (183). The other end of the feed shaft (2) is provided with a limiting ring (201), and the bearing (3) is nested with the limiting ring (201).

10. The detachable two-dimensional fine-tuning Faraday cup device according to claim 9, characterized in that, The Faraday cup assembly includes a connector (11) and a Faraday cup (12). One end of the connector (11) is detachably connected to the Faraday cup (12) by a fastener. The other end of the connector (11) is detachably connected to a threaded interface (203) by an external thread. A sealing ring (10) is provided on the end of the connector (11) and the inner side of the threaded interface (203). A through wire hole (13) is provided on the connector (11). One end of the wire is connected to the Faraday cup (12), and the other end of the wire passes through the wire hole (13) and extends to the outside through the inner hole of the feed shaft (2) to realize the transmission of electrical signals.

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