Compact high-precision nano experimental sample positioning device and method

Abstract

The invention discloses a compact high-precision nano experimental sample positioning device and method. The device comprises a sample position measuring unit, a HAKB mirror body position measuring unit, a VAKB mirror body position measuring unit and a signal processing unit, wherein the HAKB mirror body position measuring unit comprises laser heads T1 and T2 and a first V-shaped plane mirror, and the VAKB mirror body position measuring unit comprises laser heads T3 and T4 and a second V-shaped plane mirror assembly; the sample position measuring unit comprises laser heads T5, T6, T7 and T8 and a cylindrical reflecting mirror; the laser heads are integrally mounted on the portal frame, and differentiated design is carried out for different measuring units; wherein two paths of laser heads of the HAKB and VAKB lens body position measuring units are symmetrically arranged at a certain angle with the beam direction, and the laser head of the sample position measuring unit is arranged in a direction parallel to the testing direction, so that the measuring axis is consistent with the direction of the degree of freedom to be measured.

Description

Technical Field

[0001] This invention belongs to the field of synchrotron radiation technology and relates to a compact, high-precision positioning device and method for nanoscale experimental samples. Background Technology

[0002] High Energy Synchrotron Radiation Source (HEPS) possesses high brightness and high coherence. During construction, beamlines such as the Hard X-ray Coherent Scattering (HEPS) primarily utilize the unique advantages of HEPS for experiments such as Coherent X-ray Diffraction Imaging (CDI), achieving nanometer-resolution 3D structural imaging and strain imaging of samples. In actual experiments, stability is a key indicator affecting CDI experiments. This experimental mode uses AKB focusing, requiring the sample stage to have a relative positional jitter of <10nm along two directions perpendicular to the optical axis relative to the light spot, with online real-time feedback and tracking. The practical engineering challenges encountered in constructing the nanometer-precision sample positioning device include: 1) The three-dimensional spatial layout of the sample is extremely cramped. Firstly, the working distance of the focusing optics AKB is only 64mm, and this distance must also accommodate gaps for vacuum chamber partitions and optical windows, severely compressing the usable space on the sample side. Secondly, due to experimental requirements, large detection equipment such as fluorescence detectors, microscopes, electron microscopes, and pinhole detectors must be integrated simultaneously in the three-dimensional space of the sample, resulting in extreme spatial constraints on the mechanical design of the sample positioning device. 2) The metrological accuracy requirements of the sample positioning device are extremely high. To meet the ultra-high precision experimental requirements of better than 10nm, it is necessary to perform global error analysis and active compensation on the positioning device, and no error in the testing process can be ignored.

[0003] CDI experiments require nanometer-precision three-dimensional scanning of the sample, making stability a crucial factor. However, due to environmental temperature, system dynamics, and inherent structural errors, relative fluctuations in the sample's position relative to the focusing optics are unavoidable. To balance stability, the relative position between the sample stage and the optics must be <10 nm throughout the experiment (primarily in the horizontal X and vertical Z directions). To meet the coherence and stability requirements of CDI experiments, the Advanced Kirkpatric-Baez focusing lens (AKB lens) is selected for direct focusing. The AKB lens comprises a horizontal mirror (HAKB), a vertical mirror (VAKB), and corresponding attitude adjustment mechanisms. The entire structure operates in a high vacuum environment (better than 1×10⁻⁶). -7 The sample apparatus requires nanometer-precision three-dimensional scanning and high-precision rotation according to experimental requirements. The sample and the corresponding attitude adjustment mechanism must meet the requirements of a low vacuum environment (better than 1×10⁻⁶ Pa). -4Pa) is sufficient. Most importantly, the working distance between the sample and the mirror is only about 64mm. Furthermore, according to experimental requirements, the sample's three-dimensional space also integrates large detection equipment such as a fluorescence detector, microscope, pinhole camera, and electron microscope, resulting in an extremely compact mechanical design space for the sample positioning device. The spatial layout and positional relationship between the sample and the AKB mirror optical elements are as follows: Figure 1 As shown.

[0004] Through a survey of similar measurement devices at domestic and international synchrotron radiation sources, it was found that: Swiss LightSource (SLS) and Diamond Light Source I14 in the UK adopt conventional measurement methods in their design process. That is, the interferometer measurement beam is in the same direction as the motion of the object being measured. The laser interferometer of the measurement element is fixed on a third-party reference through relevant structures. Reflectors are placed on the optical element and the sample stage for measurement. Then, the relative displacement between the mirror and the sample is obtained through data processing. The literature describes that when performing stability measurements using the two light sources mentioned above, the sample stage and optical components are all in the same working environment. The Swiss SLS laser interferometer measurement device is mentioned in the literature as being able to achieve sample stability relative to X-rays at 10 nm (Reference: Peach, Andrew, et al. "Engineering Challenges on the I14 Nanoprobe Beamline." Proc. MEDSI16 (2016). And Holler, Mirko, and JörgRaabe. "Error motion compensating tracking interferometer for the position measurement of objects with rotational degree of freedom." Optical Engineering 54.5 (2015): 054101.).

[0005] The Sirius light source in Brazil also uses high-rigidity granite as a third-party reference for measurement. In this setup, the AKB mirror is in a vacuum environment while the sample is in an atmospheric environment. However, the entire metrology system is designed with high rigidity and stability for the AKB mirror's mechanical components, neglecting to account for vibrations in the optical elements. It only monitors the stability of the sample stage, making it impossible to provide real-time monitoring and feedback of the sample position according to experimental requirements. The AKB end is 440mm from the sample, resulting in significant space redundancy. Therefore, the metrology system was designed with a large, integrated, high-rigidity interferometer mounting frame. Currently, the actual operational accuracy of this system has not been mentioned in the literature (Reference: Geraldes, RR, et al. "Design and Commissioningof the TARUMÃ Station at the CARNAÚBA Beamline at Sirius / LNLS." MEDSI2020, Chicago, IL, USA, virtual conference. 2021.).

[0006] The PtyNAMi beamline of the PETRA III in Germany uses an optical element as a reference for measurement. The optical focusing element is set to remain stationary after initial calibration. A laser interferometer for position measurement is mounted on this optical element using a cantilever mechanism, and then used as a reference to measure the relative motion position of the scanned sample. In this measurement device, the optical element and the sample are in the same working environment. A spherical transmission mirror is used as the sample reflector. The paper mentions that this device meets the requirements for conventional scanning with an accuracy of 50–100 nm, but a redesign is needed for high-precision scanning below 10 nm (Reference: Schropp, Andreas, et al. "PtyNAMi: ptychographic nano-analyticalmicroscope." Journal of applied crystallography 53.4 (2020): 957-971.).

[0007] The high-precision positioning measurement method and device based on the KB mirror nano-experimental system proposed by Yu Haihan et al. in China combines a laser interferometer and a grating measurement scheme, which focuses on solving the problem of optical path layout for irregular cavity testing. However, this invention mainly focuses on the design and layout of the KB mirror side stability measurement, without introducing the sample side position measurement, which cannot meet the requirements of high-precision sample positioning. Moreover, the KB mirror stability measurement in this scheme adopts a grating scheme. The two target gratings selected in this scheme need to be matched with four plane mirrors arranged at specific diffraction angles to construct the measurement beam loop. This design of the optical path is complex and significantly increases the physical space occupied by the system, thus failing to meet the requirements of extremely compact working conditions (Reference: Yu Haihan et al. High-precision positioning measurement method and device based on KB mirror nano-experimental system: 202310055359.8 [P]. 2023-05-09.).

[0008] If a conventional measurement optical path is used for the measurement layout, that is, the interferometer probe is arranged along the direction to be measured, then when using this method for multidimensional measurement, multiple probes need to be installed in different spaces on both the sample side and the AKB mirror side, which is not conducive to the arrangement and subsequent debugging in a confined space. Moreover, this measurement method inevitably introduces the uncertainty factor brought by the third-party reference, affecting the measurement accuracy. More importantly, the third-party reference cannot span two cavities, and cannot meet the complex working conditions where the sample stage and the AKB mirror are in different vacuum environments.

[0009] If the system is built based on the optical element under test, this scheme mounts the optical element and its corresponding attitude adjustment mechanism on a highly stable gantry. This approach relies on the small size and light weight of the optical element and its corresponding attitude adjustment mechanism. However, the AKB mirror body and its corresponding attitude adjustment mechanism are large and heavy. Using a gantry structure for overall hoisting would compromise the high stability design of the AKB mirror's mechanical structure. Furthermore, the AKB mirror operates in a high-vacuum environment. If the laser interferometer probe is positioned on one side of the AKB mirror, subsequent debugging would require breaking the vacuum, which is time-consuming, labor-intensive, and detrimental to the protection of the optical element. Summary of the Invention

[0010] To address the technical problems existing in the prior art, the present invention aims to provide a compact, high-precision positioning device and method for nanoscale experimental samples. In this device, a high-rigidity gantry on the sample side is used as a reference to measure the relative displacement of the sample relative to the AKB mirror along a direction perpendicular to the beam line. All laser interferometer probes are miniaturized integrated probes, and all probes are mounted on a high-rigidity, high-stability gantry with the same reference as the sample, reducing the number of probe mounting brackets and other error sources introduced by the mounting brackets, achieving a compact and highly stable design. The AKB mirror body monitoring employs a dual-laser probe differential combined with a V-shaped plane mirror reflection test scheme. The probes for the HAKB and VAKB mirror bodies are mounted on a high-rigidity gantry located on the sample side, and the reflector is mounted on one side of the AKB mirror body. An optical window is installed on the cavity partition to allow the optical path for mirror body position testing to pass through. Adjustment functionality is retained on the probe side, while the reflector on the AKB side is essentially fixed after installation. This scheme features a simple optical path and compact structure. It not only solves the problem of arranging the optical path for measurements in two irregularly shaped vacuum cavities, but also greatly reduces the likelihood of needing to frequently open the AKB mirror's high-vacuum sealed cavity during debugging, thus improving the efficiency of offline debugging. For sample-side monitoring, to accommodate both 3D scanning and 360° rotation of the sample, the reflector on the sample side is designed as a cylinder. Simultaneously, three parallel laser interferometer probes are arranged vertically along the sample to compensate for errors and improve measurement accuracy.

[0011] This device uses a high-rigidity gantry frame sharing a common reference with the sample as the measurement benchmark to perform real-time positioning measurements of the sample's position relative to the AKB mirror's optical elements. The device mainly includes a sample stage stability measurement unit, an HAKB mirror stability measurement unit, a VAKB mirror stability measurement unit, a high-rigidity gantry frame, and a signal processing unit.

[0012] All laser interferometer probes are miniaturized, and all eight probes are mounted on a high-rigidity gantry, reducing the number of probe mounting brackets and other sources of error introduced by the mounting brackets, thus achieving a compact and highly stable design.

[0013] To accommodate the need for 3D scanning and 360° rotation of the sample, the reflector on the sample side is designed to be cylindrical. At the same time, three parallel laser interferometer probes are arranged in the vertical direction of the gantry relative to the sample to perform Abbe error compensation and improve measurement accuracy.

[0014] The AKB mirror body monitoring employs a dual-laser probe differential combined with a V-shaped plane mirror reflection testing scheme. For the measurement optical path of the two mirrors, measurements can be completed using very few optical components, making it easy to arrange in confined spaces and facilitating subsequent offline adjustments of the entire device. This scheme not only solves the challenge of arranging the measurement optical path for two irregularly shaped vacuum cavities but also greatly reduces the likelihood of frequently opening the AKB mirror's high-vacuum sealed cavity during commissioning, thus improving the efficiency of offline commissioning.

[0015] By organizing the test data, the horizontal displacement X and vertical displacement Z of the sample relative to the focused spot can be obtained as follows: The entire device is compact and easy to operate, enabling its deployment and system debugging in confined spaces. The test data processing algorithm is simple and relatively easy to understand, reducing the complexity of the work.

[0016] The technical solution of the present invention is: a compact, high-precision positioning device for nanoscale experimental samples, characterized in that it includes a sample position measurement unit, a HAKB mirror position measurement unit, a VAKB mirror position measurement unit, and a signal processing unit; The HAKB mirror position measurement unit includes two collimated laser heads T1 and T2 and a first V-shaped plane mirror; the VAKB mirror position measurement unit includes two collimated laser heads T3 and T4 and a second V-shaped plane mirror; the sample position measurement unit includes a focusing laser head T5, three collimated laser heads T6, T7 and T8, and a cylindrical mirror. The cylindrical reflector is located on the sample side, and the first V-shaped plane reflector and the second V-shaped plane reflector are located on the AKB cavity side; T1, T2, T3, T4, T6, T7 and T8 are all mounted on a gantry frame that shares a common reference with the sample; Assuming the beam propagates in a horizontal plane, the beam direction is set as the Y direction, the vertical direction perpendicular to the Y direction is set as the Z direction, and the horizontal direction perpendicular to the Y direction is set as the X direction. T1 and T2 are installed horizontally and symmetrically in the XY plane. The lasers output by T1 and T2 are at a certain angle to the Y direction. α The first V-shaped plane mirror is mounted on the HAKB mirror assembly. The mirror surfaces of the two plane mirrors are perpendicular to the laser beam paths output by T1 and T2. The measurement lasers output by T1 and T2 are incident on the corresponding plane mirror surfaces through optical windows and then return along the original path, causing interference. The signal processing unit is used to calculate the displacement between the gantry and the HAKB mirror assembly based on the interference signal. , Then, the horizontal displacement of the gantry relative to HAKB was calculated. ; T3 and T4 are installed symmetrically and perpendicularly in the YZ plane. The lasers output by T3 and T4 are at a certain angle to the Y direction. β The second V-shaped plane mirror is mounted on the high-vacuum VAKB mirror assembly. The mirror surfaces of the two plane mirrors are perpendicular to the laser beam paths output by T3 and T4. The measurement lasers output by T3 and T4 are incident on the corresponding plane mirror surfaces through optical windows and then return along the original path, causing interference. The signal processing unit is used to calculate the displacement between the gantry and the VAKB mirror assembly based on the interference signal. , Then, the vertical displacement of the gantry relative to the VAKB is calculated. ; The test beam output by T5 is parallel to the X-direction and intersects the axis of the cylindrical reflector. The cylindrical reflector returns the test beam output by T5 back to T5 along the original path, causing interference. T5 sends the detected interference signal to the displacement signal calculated by the signal processing unit. ; T6, T7, and T8 are located at the three vertices of a right triangle. The three test beams output by T6, T7, and T8 are parallel to the Z-direction and incident directly onto the upper surface of the cylindrical reflector. The cylindrical reflector returns the test beams output by T6, T7, and T8 back to their respective vertices, causing interference. T6, T7, and T8 send the detected interference signals to the signal processing unit to calculate the displacement signals respectively. , , Then the horizontal displacement of the sample relative to the AKB mirror was calculated. Vertical displacement between the sample and the AKB mirror ;in, This is the distance between T5 and the sample. The distance between T6 and T7. This is the distance between T6 and the sample.

[0017] Preferably, T6 is located at the right-angle vertex, T8 is arranged symmetrically with respect to the sample point along the parallel Y direction and T6, and T7 is closer to the sample position than T6.

[0018] Preferably, T6, T7 and T8 are mounted on a common rigid substrate; the rigid substrate is mounted on the gantry to ensure that the three test beams output by T6, T7 and T8 are parallel to the Z direction and incident on the upper surface of the cylindrical reflector.

[0019] Preferably, the first V-shaped plane mirror is composed of two symmetrical first plane mirrors and a second plane mirror along the Y direction. The mirror surface of the first plane mirror is perpendicular to the laser beam path output by T1. The measurement laser output by T1 enters the first plane mirror through the optical window and returns to T1 along the same path, causing interference. T1 sends the detected first interference signal to the signal processing unit. The signal processing unit is used to calculate the displacement between the gantry and the HAKB mirror assembly based on the first interference signal. The second plane mirror is perpendicular to the laser beam path output by T2. The measurement laser output by T2 enters the second mirror through the optical window and returns to T2 along the same path, causing interference. T2 sends the detected second interference signal to the signal processing unit. The signal processing unit is used to calculate the displacement between the gantry and the HAKB mirror assembly based on the second interference signal. .

[0020] Preferably, the second V-shaped plane mirror consists of two symmetrical third and fourth plane mirrors along the Y direction. The surface of the third plane mirror is perpendicular to the laser beam path output by T3. The measurement laser output by T3 enters the third plane mirror through the optical window and returns to T3 along the same path, causing interference. T3 sends the detected third interference signal to the signal processing unit. The signal processing unit is used to calculate the displacement between the gantry and the VAKB mirror assembly based on the third interference signal. The fourth plane mirror is perpendicular to the laser path output by T4. The measurement laser output by T4 enters the fourth mirror through the optical window and returns to T4 along the same path, causing interference. T4 sends the detected fourth interference signal to the signal processing unit. The signal processing unit is used to calculate the displacement between the gantry and the VAKB mirror assembly based on the fourth interference signal. .

[0021] Preferably, a 45° reflector is installed on the gantry. The measurement lasers output by T3 and T4 are reflected by the 45° reflector and deflected to the Y direction. The two beams after deflection maintain the same symmetrical angle β with the X direction in the YZ plane.

[0022] A positioning method based on the positioning device includes the following steps: 1) The signal processing unit calculates the displacement between the gantry and the HAKB mirror assembly based on the interference signals detected by T1 and T2. , Then, the horizontal displacement of the gantry relative to HAKB was calculated. ; 2) The signal processing unit calculates the displacement between the gantry and the VAKB mirror assembly based on the interference signals detected by T3 and T4. , Then, the vertical displacement of the gantry relative to the VAKB is calculated. ; 3) The displacement signals calculated by the signal processing unit based on the interference signals detected by T6, T7 and T8 respectively. , , Then the horizontal displacement of the sample relative to the AKB mirror was calculated. Vertical displacement between the sample and the AKB mirror ;in, This is the distance between T5 and the sample. The distance between T6 and T7. This is the distance between T6 and the sample.

[0023] The beneficial effects of this invention are as follows: 1) This invention can measure and provide online feedback on the relative position and stability of samples in real time according to experimental requirements.

[0024] 2) This invention uses a high-rigidity gantry on the sample side as a fixed measurement reference coordinate system, and sets up independent measurement optical paths for the sample side and the AKB mirror side. By synchronously acquiring measurement data from both sides and processing the data through data fusion and coordinate transformation, the relative positional relationship between the sample and the light spot is calculated in real time.

[0025] 3) The entire device has a compact mechanical structure, making it easy to operate and enabling deployment and system debugging in confined spaces. The test data processing algorithm is simple and relatively easy to understand, reducing the complexity of the work. Attached Figure Description

[0026] Figure 1 This is a schematic diagram showing the spatial arrangement and positional relationship between the AKB mirror and the sample.

[0027] Figure 2 This is a diagram of an experimental setup for nanometer-precision measurement.

[0028] Figure 3 This is the HAKB mirror position measurement unit.

[0029] Figure 4 This is the VAKB mirror position measurement unit.

[0030] Figure 5 This is the sample position measurement unit.

[0031] Figure 6 This is a schematic diagram of a 45° reflector scheme. Detailed Implementation

[0032] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings.

[0033] To address practical problems in engineering applications, this invention proposes a compact, high-precision positioning device and method for nanoscale experimental samples. The device uses a high-rigidity gantry on the sample side as a fixed measurement reference coordinate system. All eight laser probes are mounted on the high-rigidity gantry, with independent measurement optical path layouts for the sample and the AKB mirror. Then, by synchronously acquiring measurement data from both sides and performing data fusion and coordinate transformation, the relative positional relationship between the sample and the laser spot is calculated in real time. The overall measurement device is as follows: Figure 2 As shown, the device mainly includes a sample position measurement unit, a HAKB mirror position measurement unit, a VAKB mirror position measurement unit, a high-rigidity gantry measurement reference, and a signal processing unit. The HAKB mirror position measurement unit includes two small collimated laser heads (T1, T2) and a first V-shaped plane mirror. Similarly, the VAKB mirror position measurement unit includes two small collimated laser head assemblies (T3, T4) and a second V-shaped plane mirror assembly. The sample position measurement unit includes one small focusing laser head assembly (T5), three small collimated laser head assemblies (T6, T7, and T8), and a highly reflective cylindrical mirror. To achieve a highly stable layout within a limited space, all test probes are integrated and mounted on a high-rigidity gantry, and differentiated designs are implemented for different measurement units. In the HAKB and VAKB mirror position measurement units, the two laser heads are arranged symmetrically at a certain angle (0~90°) to the beam direction (Y direction). Theoretically, the larger the angle, the higher the test resolution. However, in engineering practice, a larger angle is subject to strict mechanical space constraints. Therefore, the angle value is the result of comprehensive consideration of the actual working conditions and boundary conditions. For the sample position measurement unit, the laser head is arranged in a direction parallel to the test direction to ensure that the measurement axis is consistent with the direction of the degree of freedom to be measured.

[0034] For the HAKB mirror position measurement unit, such as Figure 3 As shown. The two laser heads T1 and T2 are mounted in the XY plane, and the measurement beam of the laser head is along the beam direction (Y direction) at a certain angle ( α The components are arranged symmetrically and mounted on a high-rigidity gantry located on one side of the sample chamber. The first V-shaped plane mirror consists of two plane mirrors symmetrical along the Y-direction, with their surfaces perpendicular to the corresponding laser beam paths. These mirrors are mounted on a high-vacuum HAKB mirror assembly. Measurement lasers from both laser heads are simultaneously emitted through an optical window between the two cavities and incident on the corresponding mirrors. The emitted lasers then interfere with the laser heads, and the interference signals are processed by a signal processing unit to calculate the displacement between the gantry and the HAKB. and According to the displacement vector method, we can obtain: From this, the horizontal displacement of the gantry relative to HAKB can be obtained: For the VAKB mirror position measurement unit, such as Figure 4 As shown. The two laser heads T3 and T4 are mounted in the YZ plane, and the measurement beam of the laser head is along the beam direction Y at a certain angle ( β The components are arranged vertically and symmetrically, mounted on a high-rigidity gantry located on one side of the sample chamber. The second V-shaped plane mirror consists of two plane mirrors symmetrical along the Y-direction. The mirror surfaces of the two plane mirrors are mounted perpendicularly to the corresponding laser beam paths on the high-vacuum VAKB mirror assembly. The measurement lasers provided by the two laser heads are simultaneously incident on the corresponding mirrors through the optical windows between the two cavities, and then emitted. After being reflected back to the laser heads, interference occurs. The displacement between the gantry and the VAKB can then be obtained by the signal processing unit. and According to the displacement vector method, we can obtain: From this, the vertical displacement of the gantry relative to VAKB can be obtained: For the sample position measurement unit, such as Figure 5 As shown. For the X-direction displacement measurement of the sample, since the sample needs to rotate 360°, a highly reflective cylindrical mirror must be selected to ensure that the incident light returns along its original path. Simultaneously, a focusing laser head T5 is used for this direction measurement to increase the allowable range of the light path tilt angle reflected from the curved surface. The test beam of the laser head T5 is parallel to the X-direction and intersects the axis of the cylindrical mirror. The displacement signal obtained by the signal processing unit during the test is... For Z-direction displacement measurement of the sample, a collimated laser head is used to receive light reflected from the upper surface of a cylindrical mirror. However, considering this, when performing high-precision rotary scanning measurement experiments on the sample, the sample point and the X and Z measuring mirrors cannot be arranged on the same axis, inevitably resulting in Abbe offset between the X and Z-direction measuring laser heads mounted on the gantry and the sample point. To meet the high-precision measurement requirements of the sample, a parallel beam integrated with three collimated laser head assemblies (T6, T7, and T8) is arranged in the Z-direction of the sample for roll angle measurement. φError measurement is used to compensate for the Abbe error between the sample and the gantry, thereby improving measurement accuracy. Three laser heads are located at the three vertices of a right-angled triangle, with T6 at one of the right angles. Probe T8 is arranged symmetrically with T6 about the sample point along the parallel Y-direction, and probe T7 is closer to the sample than probe T6. After fine-tuning and calibration on a common rigid substrate, the three probes are mounted on the gantry to ensure that the three test beams are parallel to the Z-direction and incident directly on the upper surface of the cylindrical reflector. The measurement lasers provided by the three laser heads (T6, T7, and T8) are emitted after hitting the upper surface of the cylindrical reflector and interfere upon returning to their respective laser heads. The displacement signals obtained by the signal processing unit from the three probes are [signatures]. , , .

[0035] Figure 5 middle This is the distance between probe T5 and the sample point. This refers to the distance between probes T6 and T7. This is the distance between probe T6 and the sample point. The roll angle error at this point is calculated. φ for Then according to The introduced Abbe error value is obtained, and then error compensation is performed to obtain the horizontal displacement between the gantry and the sample stage. and vertical displacement value They are respectively: By integrating all the formulas, the horizontal displacement of the sample relative to the AKB mirror can be obtained. X and vertical displacement Z They are respectively: Further analysis revealed that, for the sample measurement device, in order to improve measurement accuracy, the distance between the measuring probe and the sample rotation axis should be minimized while still meeting the requirements of the engineering space layout.

[0036] Taking a certain project as an example, the sample positioning device is designed with optical path and spatial layout according to this invention, and the selected laser interferometer equipment has a displacement resolution of 25 pm (0.025 nm). For HAKB, the angle between the laser head and the beamline direction... α If it is 13°, then X KB The displacement resolution is 56 pm (0.056 nm). For VAKB, the angle between the laser head and the beamline direction is...β If the angle is 4°, then Z KB The displacement resolution is 179 pm (0.179 nm), which meets the requirements for nanometer-level displacement resolution. Systematic error analysis of this device shows that, based on compensation for Abbe errors in the sample and gantry structure, further analysis and control of the correlation errors generated by HAKB and VAKB relative to the gantry measurement module yields comprehensive errors better than 2 nm and 5 nm, respectively. In summary, this positioning device has a compact overall structure and is capable of performing experiments requiring nanometer-level precision.

[0037] The V-shaped plane mirror used in this solution for positioning and measuring the optical path backlight of the AKB mirror body can have a fixed mounting bracket or be designed to be electrically adjustable, so as to meet the testing requirements of the mirror body under different working conditions.

[0038] The laser head in the AKB mirror positioning measurement optical path of this solution is not limited to the layout shown in the example; it can also be used in conjunction with a 45° mirror reflection unit. Taking the installation positions of probes T3 and T4 as an example, for instance... Figure 6 As shown, its function is to deflect the laser beams emitted by two laser heads through a 45° reflector, allowing them to pass through an optical window and enter the V-shaped reflector at the AKB mirror end before returning along the same path. This design is suitable for engineering applications requiring more compact space. The two laser heads, T3 and T4, are mounted in the XZ plane. The measurement beams of the laser heads are arranged perpendicularly and symmetrically along the X direction at a certain angle (β), and are mounted on a high-rigidity gantry located on one side of the sample chamber. The gantry is also equipped with a 45° reflector, which deflects the two laser beams to the Y direction. The deflected beams maintain the same symmetrical angle β with the X direction in the YZ plane. The V-shaped reflector consists of two plane mirrors symmetrical along the Y direction, with the mirror surfaces perpendicular to the deflected laser beam path. This V-shaped reflector assembly is mounted on a high-vacuum VAKB mirror assembly. This scheme significantly expands the space for mounting the laser head on the sample-side gantry, providing greater flexibility for equipment installation and debugging. On the other hand, it effectively avoids the problem of the laser head being too close to the light transmission window due to the limited space along the beam direction, thereby suppressing window reflection interference and making the alignment and debugging of the measurement optical path convenient and reliable.

[0039] Although the above preferred embodiments have been described in detail, they are merely for illustrating the technical solutions of the embodiments of the present invention and not for limiting them. Those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions, but should not depart from the principles and scope of the technical solutions of the embodiments of the present invention. Any equivalent substitutions and modifications that do not depart from the principles and core features of the embodiments of the present invention should be included within the scope of the present invention, the scope of which is determined by the claims.

Claims

1. A positioning device for compact high-precision nanometric experimental samples, characterized in that, The sample position measurement unit, the HAKB mirror position measurement unit, the VAKB mirror position measurement unit and the signal processing unit are included. The HAKB mirror position measurement unit includes two collimated laser heads T1, T2 and a first V-shaped plane mirror; the VAKB mirror position measurement unit includes two collimated laser heads T3, T4 and a second V-shaped plane mirror; and the sample position measurement unit includes a focused laser head T5, three collimated laser heads T6, T7, T8 and a cylindrical mirror. The cylindrical mirror is located on the sample side, and the first and second V-shaped plane mirrors are located on the AKB cavity side; T1, T2, T3, T4, T6, T7 and T8 are all mounted on a gantry with the sample as a reference. The beam is transmitted in the horizontal plane, the beam direction is set as the Y direction, the vertical direction perpendicular to the Y direction is set as the Z direction, and the horizontal direction perpendicular to the Y direction is set as the X direction. T1, T2 are installed in X-Y plane and arranged horizontally symmetrically, and the laser output by T1, T2 has a certain angle with Y direction α , a first V-shaped plane mirror is installed on the HAKB mirror assembly, the mirror surface of the two plane mirrors is perpendicular to the laser light path output by T1, T2, the measurement laser output by T1, T2 returns along the original path after being incident on the corresponding plane mirror surface to generate interference, and the signal processing unit is used to calculate the displacement between the portal frame and the HAKB mirror assembly according to the interference signal 、 ; then the horizontal displacement of the portal frame relative to the HAKB is calculated ; T3, T4 are installed in Y-Z plane and arranged vertically symmetrically, and the laser output by T3, T4 has a certain angle with Y direction β , the second V-shaped plane mirror is installed on the high-vacuum VAKB mirror assembly; the mirror surfaces of the two plane mirrors are perpendicular to the laser light paths output by T3, T4, the measurement laser output by T3, T4 returns along the original path after being incident on the corresponding plane mirror surface, and interference occurs; the signal processing unit is used for calculating the displacement between the gantry and the VAKB mirror assembly according to the interference signal 、 ; then the vertical displacement of the gantry relative to the VAKB is calculated ; The test light beam output by T5 is parallel to the X direction and intersects with the axis of the cylindrical mirror, the cylindrical mirror returns the test light beam output by T5 to T5, and T5 sends the detected interference signal to the signal processing unit to calculate the displacement signal ; T6, T7 and T8 are located at the three vertices of a right triangle, respectively, and the three test beams output by T6, T7 and T8 are parallel to the Z direction and are normally incident on the upper surface of the cylindrical mirror; the cylindrical mirror returns the test beams output by T6, T7 and T8 to the corresponding T6, T7 and T8 by the original path, and the T6, T7 and T8 send the detected interference signals to the signal processing unit to calculate the displacement signals respectively , , , then the horizontal displacement between the sample and the AKB mirror is calculated and the vertical displacement between the sample and the AKB mirror is calculated ; wherein, is the distance between T5 and the sample, is the distance between T6 and T7, is the distance between T6 and the sample.

2. The positioning device of claim 1, wherein, T6 is located at a right angle vertex, T8 is arranged along the parallel Y direction and symmetrically about the sample point relative to T6, and T7 is closer to the sample position than T6.

3. The positioning device according to claim 1 or 2, characterized in that T6, T7 and T8 are mounted on a common rigid substrate; the rigid substrate is mounted on the gantry to ensure that the three test beams output by T6, T7 and T8 are parallel to the Z direction and are normally incident on the upper surface of the cylindrical mirror.

4. The positioning device of claim 1, wherein, The first V-shaped plane mirror is composed of two first plane mirrors symmetrical along the Y direction and a second plane mirror, the mirror surface of the first plane mirror is perpendicular to the laser light path output by T1, the measurement laser output by T1 returns to T1 along the original path after being incident on the first plane mirror through the optical window to generate interference, T1 sends the detected first interference signal to the signal processing unit; the signal processing unit is used for calculating the displacement between the gantry and the HAKB mirror assembly according to the first interference signal ; the mirror surface of the second plane mirror is perpendicular to the laser light path output by T2, the measurement laser output by T2 returns to T2 along the original path after being incident on the second mirror through the optical window to generate interference, T2 sends the detected second interference signal to the signal processing unit; the signal processing unit is used for calculating the displacement between the gantry and the HAKB mirror assembly according to the second interference signal .

5. The positioning device of claim 1, wherein, The second V-shaped plane mirror is composed of two third plane mirrors and a fourth plane mirror which are symmetrical along the Y direction, the third plane mirror is perpendicular to the laser light path output by T3, the measuring laser output by T3 returns to T3 along the original path after being incident on the third plane mirror through the optical window to generate interference, T3 sends the detected third interference signal to the signal processing unit; the signal processing unit is used for calculating the displacement between the gantry and the VAKB mirror assembly according to the third interference signal ; the fourth plane mirror is perpendicular to the laser light path output by T4, the measuring laser output by T4 returns to T4 along the original path after being incident on the fourth plane mirror through the optical window to generate interference, T4 sends the detected fourth interference signal to the signal processing unit; the signal processing unit is used for calculating the displacement between the gantry and the VAKB mirror assembly according to the fourth interference signal .

6. The positioning device of claim 1, wherein, A 45° mirror is mounted on the gantry, and the measurement laser beams output by T3 and T4 are reflected by the 45° mirror and turned to the Y direction; the two turned beams maintain the same symmetric angle β with the X direction in the Y-Z plane.

7. A positioning method based on the positioning device of claim 1, comprising the following steps: 1) The signal processing unit calculates the displacement between the gantry and the HAKB mirror assembly from the interference signals detected by T1 and T2 , ; then calculates the horizontal displacement of the gantry relative to HAKB ; 2) the signal processing unit calculates the displacement between the gantry and the VAKB mirror assembly based on the interference signals detected by T3, T4 , ; and then calculates the vertical displacement of the gantry relative to VAKB ; 3) the signal processing unit calculates the displacement signals from the interference signals detected by T6, T7 and T8 respectively , , then calculates the horizontal displacement between the sample and the AKB mirror and the vertical displacement between the sample and the AKB mirror ; wherein, is the distance between T5 and the sample, is the distance between T6 and T7, is the distance between T6 and the sample.

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