A position correction method for rapid acquisition of a transmission electron microscope

Abstract

The application provides a position correction method for rapid collection of a transmission electron microscope, which is used for transmission electron microscope images collected at multiple angles; through mathematical fitting of the relationship between the image position (horizontal coordinate x, vertical coordinate y) and the focus value focus and the sample rod tilt angle angle, the position error and the focus change caused by the tilt are effectively corrected, so that the alignment accuracy and the imaging quality of the image are improved; the method uses a fitting function, and accurate numerical value can greatly improve the correction efficiency and automation, and has significant technical progress and application value in improving the multi-angle imaging and three-dimensional reconstruction of the transmission electron microscope.

Description

Technical Field

[0001] This invention belongs to the field of electron microscopy technology, and particularly relates to a method for rapid acquisition and position correction in transmission electron microscopy. Background Technology

[0002] Transmission electron microscopy (TEM) is an important scientific instrument for materials research and characterization, and it is widely used in materials science, biology, microelectronics and other fields. Rapid acquisition and multi-angle imaging in TEM are very important technical requirements in TEM characterization. However, due to the limitation of precise position correction, it is difficult to automate the acquisition process.

[0003] Although high-precision sample stages can achieve fine displacement control, mechanical errors can still cause sample position shifts during multi-angle acquisition. Currently, commercial automated systems can achieve automated sample acquisition to a certain extent through complex optical path fitting, but they are difficult to operate and have high maintenance costs. Especially when frequent adjustments and calibrations are required, they may cause image blurring, which is a significant obstacle to subsequent image processing.

[0004] The importance of rapid acquisition in tomographic reconstruction is disclosed in the literature J. Phys. Chem. C, 2020, 124, 27276−2728, Sci. Rep. 2015, 5, 14516., and rapid data acquisition and 3D reconstruction are achieved through image recording and post-image optimization processing. However, researchers are limited to acquiring small particles within a large field of view. During the acquisition process, the particles will not shift beyond the field of view. Alternatively, they use manual movement and adjustment to quickly move the particles into the field of view. The position correction of these methods is not accurate enough, and the degree of automation is not high. Summary of the Invention

[0005] To address the shortcomings and deficiencies of existing technologies, this invention proposes a rapid position correction method for transmission electron microscopy (TEM) acquisition. This method provides a fast and accurate position correction approach applicable to TEM images acquired from multiple angles. By mathematically fitting the relationship between image position (x-axis, y-axis) and focus value with the sample rod tilt angle, it effectively corrects position errors and focus variations caused by tilting, thereby improving image alignment accuracy and imaging quality. This method utilizes a fitting function; accurate numerical substitution greatly enhances correction efficiency and automation, demonstrating significant technological advancement and application value in improving multi-angle imaging and 3D reconstruction in TEM.

[0006] The present invention specifically adopts the following technical solution:

[0007] A method for rapid acquisition and position correction in transmission electron microscopy:

[0008] Using a tilting electron microscope sample stage, the x-coordinate, y-coordinate, and focus value were collected to represent the optimal imaging state of the electron microscope at different tilting angles.

[0009] With the tilt angle as the independent variable and the x-coordinate, y-coordinate, and focus value as the dependent variables, the functional relationship was obtained through mathematical fitting.

[0010] The obtained functional relationship is used to correct multi-angle images captured by transmission electron microscopy.

[0011] Furthermore, the tilt angle is in the range of -70° to 70°.

[0012] Furthermore, the method for collecting data at different tilt angles is as follows: First, set the x-coordinate, y-coordinate, and focus value to 0 for the initial optimal shooting state.

[0013] Then adjust the sample stage to the maximum value in the positive or negative direction of the tilt angle, adjust the sample to the center of the field of view, adjust the focus value to the best imaging state, and record the horizontal axis, vertical axis and focus value at this time;

[0014] The sample stage is tilted at a fixed step angle to obtain the x-coordinate, y-coordinate, and focus value under the optimal imaging state at each angle, until the maximum value is reached in the other direction of the tilt angle.

[0015] Furthermore, polynomial functions are used to fit the x-coordinate and y-coordinate.

[0016] Furthermore, the focus value is fitted using a linear function.

[0017] Furthermore, a corresponding control system for a transmission electron microscope is characterized in that, when continuously acquiring transmission electron images from different angles, a position correction program is run, which is further compiled using the functional relationship obtained by the above method.

[0018] A transmission electron microscope employing the control system described above.

[0019] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements a position correction program that further compiles the functional relationship obtained by the method described above.

[0020] A non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements a position correction program that further compiles the functional relationships obtained by the method described above.

[0021] Compared with existing technologies, the present invention and its preferred embodiment provide a scheme that uses angle values ​​as acquisition variables to automatically adjust position coordinates and focusing height, enabling high-precision acquisition of transmission and scanning transmission images of nanoparticles.

[0022] This invention relates to a rapid acquisition position correction method, program, and system device for transmission electron microscopy (TEM). It is based on a mathematical fitting method that addresses the changes in the x and y positions and focus value of an image as a function of the sample rod's tilt angle during multi-angle acquisition. By introducing this mathematical fitting method, the technique can accurately correct displacement errors of the sample at different tilt angles. This fitting method can significantly improve the accuracy of image alignment and reconstruction, reduce manual adjustments and error accumulation, and reduce image position deviation to less than 10% of the original error. The new correction method can process and correct multi-angle acquired data more quickly, reducing image processing time by more than 50% and improving overall experimental efficiency.

[0023] This method optimizes the experimental procedure, simplifies operation, and saves time and energy consumption. Higher image correction accuracy provides a more reliable data foundation for subsequent scientific research, which is particularly important for fine structure analysis and materials research. In practical applications, this method improves data reproducibility, enhances the credibility of scientific conclusions, and has significant technical and economic benefits, providing strong support for multi-angle imaging research in transmission electron microscopy. Attached Figure Description

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0025] Figure 1 This is a comparison chart of the offsets before and after the correction of the horizontal axis (x) and vertical axis (y) in the embodiment of the present invention.

[0026] Figure 2 This is a comparison chart of the offset before and after focus correction in the embodiment of the present invention;

[0027] Figure 3 This is a diagram illustrating the effect of reducing data acquisition time using an automatic correction algorithm in an embodiment of the present invention.

[0028] Figure 4 This is a basic implementation flowchart of an embodiment of the present invention. Detailed Implementation

[0029] To make the features and advantages of this patent more apparent and understandable, specific embodiments are provided below for detailed explanation:

[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0031] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise.

[0032] like Figure 4 As shown in the embodiment of the present invention, the method for rapid acquisition and position correction using a transmission electron microscope involves the following steps:

[0033] The first step involves acquiring data points from a transmission electron microscope (TEM). The control program and modules are connected to the TEM, and a suitable sample area is selected. Initially, with the tilt angle at 0 degrees, the TEM is adjusted to the optimal imaging state, and the program records the x-coordinate, y-coordinate, and focus value at this point. The TEM sample stage is then tilted, and an appropriate step size is selected. Within a reasonable tilt angle range, a certain number of angles are selected, and the x-coordinate, y-coordinate, and focus value are recorded respectively, resulting in a series of acquired data. This data is then saved in the running program.

[0034] The second method is the mathematical fitting of data points. Using the saved data, with the tilt angle as the independent variable and the x-coordinate, y-coordinate, and focus value as the dependent variables, the functional relationships of x-coordinate = F(angles), y-coordinate = G(angles), and focus value = H(angles) are fitted.

[0035] The obtained functional relationship is then compiled into a transmission electron microscope program; the sample area to be acquired is selected, the compiled program is run, the electron microscope image is automatically acquired, and the image is saved.

[0036] As a preferred option, the sample image can be adjusted to the optimal state every 5° within the range of sample stage tilt angle from -70° to 70°.

[0037] The following two embodiments further illustrate the solution and effects of the present invention:

[0038] Example 1

[0039] Example of data acquisition and mathematical fitting correction for transmission electron microscopy data points:

[0040] (1) At a magnification of 20,000 times, find the observation particle with a sample size of 300 nm, move the particle to the center of the field of view, adjust the sample height to the best imaging state, make the focus value focus 0, and set the horizontal axis to 0 and the vertical axis to 0 at this time.

[0041] After adjusting the sample stage to -65°:

[0042] (2) Adjust the sample to the center of the field of view, adjust the focus value to the best imaging state, and record the horizontal axis, vertical axis and focus value at this time;

[0043] (3) Increase the sample stage angle to 65° in increments of 4°, and repeat step (2) to obtain the abscissa, ordinate and focus value for each angle;

[0044] (4) Fit the x and y coordinates using a 5th-order polynomial function, and fit the focus value using a linear function;

[0045] (5) Apply the mathematical fitting function to position correction and observe the data offset; the offset of the horizontal and vertical axes is as follows: Figure 1 As shown, before correction, the x and y shifts were large, especially the y-value shift exceeding 2 micrometers; after correction, the x and y shifts were smaller and could be controlled within 40 nm. Figure 2 As shown, the focus value shifted by more than 3 micrometers before correction and by less than 200 nm after correction; this can meet the acquisition requirements of nanomaterials.

[0046] Example 2

[0047] Example of rapid acquisition of platinum-zinc nanoparticles:

[0048] (1) Apply the mathematical fitting function to the data acquisition of platinum-zinc nanoparticles. First, find the sample area to be acquired, adjust the sample height to the best imaging state, and make the focus value 0. The program sets the horizontal axis to 0 and the vertical axis to 0 at this time.

[0049] (2) Run the compiled position correction function to continuously acquire transmission electron images at different angles. The acquisition angle is from -65° to 65°, the acquisition step size is set to 1°, the rotation waiting time for each angle is set to 1 second, the acquisition exposure time is set to 1.5 seconds, the program relaxation time is 1.5 seconds, and the total acquisition time is 520 seconds.

[0050] (3) The collection effect is as follows Figure 3 As shown; commercial software typically takes 1 to 2 hours to collect data, while this program can reduce the collection time to within 10 minutes.

[0051] The above are merely embodiments of the present invention. Magnification, angle selection, image size, function type, etc., are not intended to limit the present invention. Those skilled in the art will understand that any modifications, equivalent substitutions, improvements, etc., made within the scope of the methods of the present invention are all included within the scope of the claims of the present invention.

[0052] This patent is not limited to the above-described preferred embodiment. Anyone can derive other forms of position correction methods for rapid acquisition using a transmission electron microscope based on the inspiration of this patent. All equivalent variations and modifications made within the scope of this patent application shall fall within the scope of this patent.

Claims

1. A method for rapid acquisition and position correction using a transmission electron microscope, characterized in that: Using a tilting electron microscope sample stage, the x-coordinate, y-coordinate, and focus value were collected to represent the optimal imaging state of the electron microscope at different tilting angles. With the tilt angle as the independent variable and the x-coordinate, y-coordinate, and focus value as the dependent variables, the functional relationship was obtained through mathematical fitting. The obtained functional relationship is used to correct the multi-angle imaging of the transmission electron microscope; The tilt angle is within the range of -70° to 70°; The method for collecting data at different tilt angles is as follows: First, set the initial optimal shooting state with the x-coordinate, y-coordinate, and focus value all set to 0. Then adjust the sample stage to the maximum value in the positive or negative direction of the tilt angle, adjust the sample to the center of the field of view, adjust the focus value to the best imaging state, and record the horizontal axis, vertical axis and focus value at this time; The sample stage is tilted at a fixed step size to obtain the x-coordinate, y-coordinate and focus value of the optimal imaging state at each angle, until the maximum value in the other direction of the tilt angle is reached. Fit the x and y coordinates using a polynomial function; The focus value is fitted using a linear function.

2. A control system for a transmission electron microscope, characterized in that, When continuously acquiring transmission electron images from different angles, a position correction program is run, which is further compiled using the functional relationship obtained by the method described in claim 1.

3. A transmission electron microscope, characterized in that, The control system described in claim 2 is adopted.

4. An electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements a position correction program that further compiles the functional relationship obtained by the method as described in claim 1.

5. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements a position correction program that further compiles the functional relationship obtained by the method as described in claim 1.

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