Method for in-situ verification of performance indexes of high-voltage power supply in transmission electron microscope

Abstract

The invention relates to the technical field of high-voltage power supply performance testing, in particular to a method for verifying performance indexes of a high-voltage power supply in situ in a transmission electron microscope. The method comprises the following steps: based on an electron wavelength model and a resolution model, determining the influence on electron wavelength and resolution when ripples and noise exist in acceleration voltage output by a high-voltage power supply; based on the quality of an imaging image of the transmission electron microscope when the acceleration voltage contains different ripples, determining the influence of the ripples on the image resolution; and determining the influence of the voltage stability on the image stability based on the contrastive analysis of the quality of the imaged images when the standard high-voltage power supply and the to-be-tested high-voltage power supply are respectively adopted in the preset time. According to the invention, the theoretical analysis of the power supply performance is realized by establishing the electron wavelength model and the resolution model; through the analysis of the resolution and stability of the imaging of the transmission electron microscope, the power supply performance is tested in the actual working environment of the transmission electron microscope, so that the in-situ verification of the high-voltage power supply performance is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of high-voltage power supply performance testing, and in particular to a method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope. Background Art

[0002] The high-voltage power supply (HVPS) in a transmission electron microscope (TEM) is a crucial component of the microscope's power supply system. It provides the electron accelerating voltage needed to generate a single-wavelength electron beam and is a key factor influencing the microscope's resolution. High-voltage power supply performance is a key metric for evaluating TEM performance, and therefore, verifying HVPS performance has become a key industry concern.

[0003] Currently, the performance verification of high-voltage power supplies in transmission electron microscopes relies on ex-situ testing. This involves using external instruments to independently test power supply parameters. This testing method is divorced from the actual working environment of the transmission electron microscope and cannot truly reflect the impact of high-voltage power supply performance indicators on transmission electron microscope performance. Summary of the Invention

[0004] In view of this, the present invention provides a method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope, so as to solve the problem of how to perform in-situ testing on a high-voltage power supply.

[0005] In a first aspect, the present invention provides a method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope, the method comprising: determining, based on an electron wavelength model and a resolution model, the influence of ripple and noise on electron wavelength and resolution when the acceleration voltage output by the high-voltage power supply is present, to obtain a first influence result; determining, based on the quality of an imaging image of a transmission electron microscope when different ripples are contained in the acceleration voltage output by the high-voltage power supply, the influence of ripple on image resolution, to obtain a second influence result; determining, based on a comparative analysis of the quality of imaging images of a transmission electron microscope when a standard high-voltage power supply and a high-voltage power supply to be tested are used within a preset time period, the influence of voltage stability on image stability, to obtain a third influence result; and characterizing the performance indicators of the high-voltage power supply based on the first influence result, the second influence result, and the third influence result.

[0006] In the present invention, by establishing an electron wavelength model and a resolution model, a theoretical analysis of power supply performance is achieved; by analyzing the resolution and stability of transmission electron microscope imaging, the power supply performance is tested in the actual working environment of the transmission electron microscope, thereby achieving in-situ verification of high-voltage power supply performance.

[0007] In an optional embodiment, based on the electron wavelength model and the resolution model, the influence of ripple and noise in the acceleration voltage output by the high-voltage power supply on the electron wavelength and resolution is determined. Before obtaining the first influence result, the method also includes: determining the relationship between the acceleration voltage output by the high-voltage power supply and the electron wavelength of the electron beam output by the transmission electron microscope based on the de Broglie formula to obtain the electron wavelength model; based on the Abbe imaging principle and the Rayleigh criterion, determining the theoretical resolution limit of the lens electron microscope to obtain the resolution model, and the resolution model includes the relationship between the electron wavelength and the resolution.

[0008] In the present invention, theoretical analysis is performed based on the de Broglie formula to realize the construction of the electron wavelength model; theoretical analysis is performed based on the Abbe imaging principle and the Rayleigh criterion to realize the construction of the resolution model. The construction of these two models provides a theoretical basis for the subsequent analysis of ripple and noise.

[0009] In an optional embodiment, based on the electron wavelength model and the resolution model, the influence of ripple and noise in the acceleration voltage output by the high-voltage power supply on the electron wavelength and resolution is determined to obtain a first influence result, including: determining the first change of the electron wavelength when different ripple signals are superimposed on the acceleration voltage based on the electron wavelength model; determining the influence of the ripple on the resolution based on the first change of the electron wavelength and the resolution model; using a random process to simulate the fluctuation in the acceleration voltage when noise exists, to obtain a randomly fluctuating voltage value; determining the second change of the electron wavelength based on the electron wavelength model and the randomly fluctuating voltage value; determining the influence of the fluctuation of the acceleration voltage when noise exists on the resolution based on the second change of the electron wavelength and the resolution model.

[0010] In the present invention, by superimposing different ripple signals on the accelerating voltage and combining the electron wavelength model and the resolution model, the influence of high-voltage power supply ripple on the resolution of transmission electron microscope images is analyzed. By using a random process to simulate the fluctuation of the high-voltage power supply when there is noise, a theoretical basis is provided for studying the influence of high-voltage power supply stability on the stability of transmission electron microscope images.

[0011] In an optional embodiment, based on the quality of the imaging image of the transmission electron microscope when the acceleration voltage output by the high-voltage power supply contains different ripples, the influence of the ripple on the image resolution is determined to obtain a second influence result, including: applying different ripple signals to the acceleration voltage output by the high-voltage power supply, in situ testing the bright field image formed by the standard sample in the transmission electron microscope under different ripple signals; calculating the resolution and signal-to-noise ratio of the bright field image corresponding to different ripple signals to obtain the second influence result.

[0012] In the present invention, the bright field image of the transmission electron microscope is tested when different ripple signals are applied, and the resolution and signal-to-noise ratio of the bright field image are calculated, thereby achieving a direct correlation between the performance of the high-voltage power supply and the quality of the transmission electron microscope.

[0013] In an optional embodiment, before applying different ripple signals to the acceleration voltage output by the high-voltage power supply and in-situ testing the bright field image formed by the transmission electron microscope under different ripple signals, the method also includes: obtaining the bright field image formed by the transmission electron microscope on the standard sample; and calculating the indication error and calibration coefficient of the bright field image.

[0014] In the present invention, before obtaining a bright field image, the indication error and calibration coefficient of the transmission electron microscope are calculated to determine whether the transmission electron microscope needs to be calibrated. This can more reliably analyze the influence of high-voltage power supply ripple on the resolution of the transmission electron microscope image.

[0015] In an optional embodiment, based on a comparative analysis of the quality of imaging images of a transmission electron microscope when a standard high-voltage power supply and a high-voltage power supply to be tested are used respectively within a preset time period, the influence of voltage stability on image stability is determined, and a third influence result is obtained, including: when a standard high-voltage power supply is used, a plurality of first bright-field images formed by the transmission electron microscope within a preset time period are obtained; a first relationship between the drift amount and the resolution attenuation rate of the plurality of first bright-field images and voltage fluctuations is calculated; when a high-voltage power supply to be tested is used, a plurality of second bright-field images formed by the transmission electron microscope within a preset time period are obtained; a second relationship between the drift amount and the resolution attenuation rate of the plurality of second bright-field images and voltage fluctuations is calculated; and a third influence result is obtained based on the first relationship and the second relationship.

[0016] In the present invention, by comparing and analyzing the standard high-voltage power supply and the high-voltage power supply to be tested, data support is provided for subsequent improvement and optimization of the high-voltage power supply to be tested.

[0017] In an optional embodiment, the electron wavelength model is expressed using the following formula:

[0018]

[0019] Where λ represents the electron wavelength and U represents the accelerating voltage;

[0020] The resolution model is expressed as follows:

[0021]

[0022] Where r represents the theoretical resolution limit and β represents the collection angle of the objective lens.

[0023] In the present invention, the above formula can be used to quantitatively analyze the relationship between electron wavelength and resolution.

[0024] In a second aspect, the present invention provides a device for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope, the device comprising: a theoretical analysis module for determining, based on an electron wavelength model and a resolution model, the influence of ripple and noise in the acceleration voltage output by the high-voltage power supply on the electron wavelength and resolution, and obtaining a first influence result; a resolution analysis module for determining, based on the quality of the imaging image of the transmission electron microscope when the acceleration voltage output by the high-voltage power supply contains different ripples, the influence of ripple on the image resolution, and obtaining a second influence result; a stability analysis module for determining, based on a comparative analysis of the quality of the imaging image of the transmission electron microscope when a standard high-voltage power supply and a high-voltage power supply to be tested are used within a preset time period, the influence of voltage fluctuations on image stability, and obtaining a third influence result; a performance characterization module for characterizing the performance indicators of the high-voltage power supply based on the first influence result, the second influence result, and the third influence result.

[0025] In a third aspect, the present invention provides a computer device comprising: a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the computer instructions to thereby execute the method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope according to the first aspect or any corresponding embodiment thereof.

[0026] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope according to the first aspect or any corresponding embodiment thereof.

[0027] In a fifth aspect, the present invention provides a computer program product comprising computer instructions for causing a computer to execute the method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope according to the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 1 is a flow chart of a method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope according to an embodiment of the present invention;

[0030] Figure 21 is a flow chart of another method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope according to an embodiment of the present invention;

[0031] Figure 3 is a graph showing the relationship between electron wavelength and acceleration voltage according to an embodiment of the present invention;

[0032] Figure 4 is a curve showing changes in electron wavelength over time at different ripple amplitudes according to an embodiment of the present invention;

[0033] Figure 5 is a statistical diagram of electron wavelength fluctuation when voltage stability is ≤10ppm according to an embodiment of the present invention;

[0034] Figure 6 1 is a structural block diagram of an apparatus for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope according to an embodiment of the present invention;

[0035] Figure 7 Schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0036] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0037] According to an embodiment of the present invention, a method embodiment for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0038] This embodiment provides a method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope, which can be used in electronic devices such as computers, mobile phones, tablet computers, etc. Figure 1 FIG. 1 is a flow chart of a method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0039] Step S101 : Based on the electron wavelength model and the resolution model, determine the influence of ripple and noise in the acceleration voltage output by the high-voltage power supply on the electron wavelength and resolution, and obtain a first influence result.

[0040] Specifically, the working principle of a transmission electron microscope is to utilize an electron beam to penetrate a sample, and to image the signal generated by the interaction between the electron and the sample, thereby obtaining the microstructural information of the sample. Wherein, the electron gun in the transmission electron microscope is the source of the electron beam, and the electron gun is provided with a high voltage for operation by a high-voltage power supply, and the wavelength of the electron beam generated by the electron gun is the electron wavelength. The electron wavelength model in the present embodiment characterizes the relationship between the electron wavelength and the acceleration voltage, while the resolution model characterizes the relationship between the electron wavelength and the resolution. Thus, through these two models, with the electron wavelength as the intermediate link, the association between the resolution and the acceleration voltage can be achieved. Wherein, the resolution refers to the resolution of a transmission electron microscope. When determining the electron model and the resolution model, it can be determined by theoretically analyzing the relevant data.

[0041] In addition, the high-voltage power supply verified in this embodiment is a DC high-voltage power supply. Among them, when the high-voltage power supply outputs an acceleration voltage, the acceleration voltage will contain ripple and noise. When verifying the performance of the high-voltage power supply, this embodiment uses a pre-constructed electron wavelength model and resolution model to analyze the ripple and noise contained in the voltage output by the high-voltage power supply. Specifically, this embodiment superimposes ripple and noise on the acceleration voltage, and through theoretical analysis of the change in the acceleration voltage after superimposing the ripple and noise, based on the electron wavelength model and the resolution model, determines the influence of ripple and noise on the electron wavelength, and further determines the influence on the resolution, thereby determining the first influence result. Therefore, through the first influence result, it is possible to theoretically analyze the influence of parameters such as ripple and stability of the high-voltage power supply on the resolution and stability of the transmission electron microscope.

[0042] Step S102 : determining the influence of the ripple on the image resolution based on the quality of the image formed by the transmission electron microscope when the acceleration voltage output by the high-voltage power supply contains different ripples, and obtaining a second influence result.

[0043] To verify the performance of the high-voltage power supply in situ, this example analyzes the image quality obtained during operation using a transmission electron microscope. This step primarily analyzes changes in image quality when the high-voltage power supply includes ripple. Specifically, by applying different ripple levels to the accelerating voltage, corresponding images are acquired. The image quality, such as resolution, is then analyzed to determine the impact of ripple on image resolution.

[0044] Step S103, based on the comparative analysis of the quality of the imaging image of the transmission electron microscope when the standard high-voltage power supply and the high-voltage power supply to be tested are respectively used within a preset time, the influence of voltage fluctuation on image stability is determined to obtain a third influence result. Specifically, in order to further verify the performance of the high-voltage power supply, this embodiment compares and analyzes the image quality of the transmission electron microscope imaging when the standard high-voltage power supply and the high-voltage power supply to be tested are respectively used. Among them, the standard high-voltage power supply can be understood as a power supply that has passed performance verification or whose performance meets the requirements. The high-voltage power supply to be tested is a power supply that needs to be performance verified. When performing stability verification, the imaging image of the lens electron microscope is obtained when it is working for a long time, such as continuously working for eight hours or more, and then the third influence result is obtained by comparing the image changes when the two power supplies are used. It should be noted that under long-term operation, the voltage output by the high-voltage power supply may fluctuate. Therefore, the impact of voltage fluctuations can be reflected by image changes.

[0045] In step S104, the performance indicators of the high-voltage power supply are characterized based on the first, second, and third impact results. Specifically, the first impact result allows theoretical verification of the high-voltage power supply's performance. Furthermore, the second and third impact results allow for direct correlation between power supply performance and the microscope's functionality, measured through image resolution and stability, by testing the power supply's performance in the actual operating environment of a transmission electron microscope. Thus, these impact results enable in-situ dynamic verification of the high-voltage power supply.

[0046] The method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope provided by an embodiment of the present invention realizes theoretical analysis of power supply performance by establishing an electron wavelength model and a resolution model; and realizes testing of power supply performance in the actual working environment of the transmission electron microscope by analyzing the resolution and stability of the transmission electron microscope imaging, thereby realizing in-situ verification of the high-voltage power supply performance.

[0047] In this embodiment, a method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope is provided. The process includes the following steps:

[0048] In step S200, the relationship between the acceleration voltage output by the high-voltage power supply and the electron wavelength of the electron beam output by the transmission electron microscope is determined based on the de Broglie formula to obtain an electron wavelength model; based on the Abbe imaging principle and the Rayleigh criterion, the theoretical resolution limit of the lens electron microscope is determined to obtain a resolution model, which includes the relationship between the electron wavelength and the resolution.

[0049] Specifically, the de Broglie formula characterizes the relationship between the wavelength of matter waves and the momentum of particles. In a transmission electron microscope, the electron beam generated by the electron gun is accelerated by the accelerating voltage output by the high-voltage power supply. That is, the kinetic energy of the electron beam can be determined by the accelerating voltage. At the same time, the relationship between kinetic energy and momentum can be further combined and brought into the de Broglie formula. From this, the electron wavelength model can be obtained, which is expressed as follows:

[0050]

[0051] Where λ represents the electron wavelength, U represents the acceleration voltage, and the unit of the electron wavelength is nanometer.

[0052] In addition, the Abbe imaging principle believes that the imaging process of an object can be divided into two steps. The first step is that the incident light undergoes Fraunhofer diffraction through the object plane, forming a series of diffraction spots on the back focal plane of the objective lens; the second step is that these diffraction spots act as new wavelet sources, interfering and superimposing on the image plane to form the image of the object. The Rayleigh criterion is a standard for judging whether two adjacent object points can be distinguished. When the distance between the centers of the diffraction patterns of the two object points is equal to the radius of the Airy disk (the central bright spot of the diffraction spot), the two object points can just be distinguished. Therefore, combining Abbe imaging and the Rayleigh criterion, the theoretical resolution limit of the lens electron microscope can be obtained, and expressed by the following formula:

[0053]

[0054] Where r represents the theoretical resolution limit, and β represents the collection angle of the objective lens. The collection angle is related to the objective lens size, aberrations, and aperture. According to this formula and the electron wavelength model mentioned above, the higher the accelerating voltage, the smaller the electron beam wavelength, and the larger the collection angle, the smaller the theoretical resolution limit of the transmission electron microscope, that is, the higher the resolution.

[0055] Step S201 : Based on the electron wavelength model and the resolution model, determine the impact of ripple and noise in the acceleration voltage output by the high-voltage power supply on the electron wavelength and resolution, and obtain a first impact result.

[0056] Specifically, the above step S201 includes:

[0057] Step S2011, based on the electron wavelength model, determines the first change of the electron wavelength when different ripple signals are superimposed on the acceleration voltage; wherein, in this embodiment, the superimposed ripple signal is a sinusoidal ripple signal, which is represented by U′=U msin(2πft). When the ripple signal is introduced, the change in acceleration voltage can be expressed as U+U′. Furthermore, through the electron wavelength model, it can be obtained that when the acceleration voltage changes, the change in electron beam wavelength is expressed as Δλ=λ(U+U′)-λ(U). Therefore, the influence of ripple on electron wavelength can be quantitatively analyzed through this change.

[0058] Step S2012 determines the effect of ripple on resolution based on the first change in electron wavelength and the resolution model. Specifically, the first change in electron wavelength and the resolution model can be used to further determine the effect of ripple on the resolution of the lens electron microscope. When analyzing the effect of ripple on the resolution of a transmission electron microscope, the ripple size can be varied to obtain resolution data when different ripples are superimposed. The ripple and corresponding resolution data can then be fitted to establish a mathematical model between the two. This mathematical model can then be used to analyze the trend of resolution changes with ripple.

[0059] In step S2013, a random process is used to simulate the fluctuations in the acceleration voltage when noise is present, thereby obtaining a randomly fluctuating voltage value. Specifically, the high-frequency noise contained in the voltage output by the high-voltage power supply can be approximated as Gaussian white noise, a random process with a normal distribution probability density function. Therefore, a random process can be used to describe the uncertainty and random fluctuations of the high-voltage power supply. Specifically, a normal distribution is used to describe the random errors and irregularities in the acceleration voltage output by the high-voltage power supply.

[0060] When Gaussian white noise is used to simulate random voltage fluctuations, according to the 3σ principle, the normal distribution with a specified standard deviation for the electron wavelength can be obtained as shown below:

[0061] σ=(M×U) / 3

[0062] Where U is the specified mean of the output accelerating voltage, σ is the specified standard deviation, and M represents the Gaussian white noise injected into the accelerating voltage that meets the stability requirements. Depending on the stability requirements of different high-voltage power supplies, M can take values ​​such as 5ppm, 8ppm, and 10ppm.

[0063] Convert the standard normal distribution Z~N(0,1) to a normal distribution with a specified mean and standard deviation, then the randomly fluctuating voltage value is:

[0064]

[0065] Step S2014: determining a second change in the electron wavelength based on the electron wavelength model and the randomly fluctuating voltage value; specifically, according to the electron wavelength model, when the acceleration voltage fluctuates randomly, the change in the electron wavelength can be expressed as:

[0066] Δλ=λ(U″)-λ(U)

[0067] Step S2015 determines the effect of the acceleration voltage fluctuation on the resolution when noise is present, based on the second change in electron wavelength and the resolution model. Specifically, similar to step S2012 above, when the acceleration voltage fluctuates with noise, causing the electron wavelength to undergo a second change, the resolution model can be used to further determine the effect of noise on the TEM resolution. When analyzing the effect of noise on the TEM resolution, the corresponding resolution data can be determined based on the noise change. The noise and the corresponding resolution data can then be fitted to establish a mathematical model between the two, and this mathematical model can be used to analyze the trend of resolution changes with noise.

[0068] Step S202 , based on the quality of the image formed by the transmission electron microscope when the accelerating voltage output by the high-voltage power supply contains different ripples, determine the influence of the ripple on the image resolution and obtain a second influence result.

[0069] Specifically, the above step S202 includes:

[0070] Step S2021: Obtain a brightfield image of a standard sample formed by a transmission electron microscope; calculate the indication error and calibration coefficient of the brightfield image. Specifically, before actually testing the impact of ripple on imaging quality, this embodiment first calculates the calibration coefficient inherent in the transmission electron microscope. At this point, a standard sample can be tested on the transmission electron microscope, and the brightfield image of the sample (such as the grid spacing) can be observed. The grid spacing measurement value T is measured using transmission electron microscope image analysis software. Based on the standard grid spacing value T0, the indication error Δ and calibration coefficient η of the magnification are calculated.

[0071]

[0072] Among them, the measurement of grid spacing can be achieved by using image analysis software commonly used in transmission electron microscopes, such as Digital Micrograph, i-TEM and other software. By calculating the indication error and calibration coefficient, the error in the transmission electron microscope itself can be determined to determine the reliability of subsequent measurement results. For example, after calculating the indication error and calibration coefficient, the transmission electron microscope itself can be calibrated according to the calculated values ​​to make the subsequent measured spacing and other data closer to the true value. In addition, a unified test standard can be established through the calculated indication error and calibration coefficient, that is, the same calibration coefficient is used in subsequent tests of different ripple signals to ensure data consistency and comparability.

[0073] In step S2022, different ripple signals are applied to the acceleration voltage output by the high-voltage power supply, and the bright field images of the standard sample formed under the transmission electron microscope under different ripple signals are tested in situ. Specifically, different ripple signals can be applied to the high-voltage power supply by artificial methods, and the bright field images of the standard sample formed by the transmission electron microscope when the different ripple signals are applied are tested in situ.

[0074] Step S2023, calculate the resolution and signal-to-noise ratio of the bright field images corresponding to different ripple signals to obtain a second impact result. Specifically, for the multiple bright field images obtained, the Fourier transform method or the edge detection method can be used to extract the resolution. Among them, the Fourier transform method can be used to perform Fourier transform on the collected bright field image to obtain a frequency domain image. In the frequency domain, the highest resolvable frequency peak corresponds to the lattice fringe spacing of the sample, which can be converted into spatial resolution through inverse transformation. The edge detection method can directly measure the lattice fringe spacing by detecting the edges of the lattice fringes and calculating the distance between adjacent fringes. For the signal-to-noise ratio, it can be determined by the ratio of signal intensity to noise intensity. In the image, the signal intensity can be represented by the average grayscale value of the lattice fringe area, and the noise intensity can be represented by the standard deviation of the grayscale value of the background area.

[0075] Furthermore, resolution is a key metric for measuring a transmission electron microscope's ability to resolve tiny structures. When studying high-voltage power supply performance, analyzing the change in resolution under different ripple voltages provides a direct understanding of the impact of high-voltage power supply ripple on transmission electron microscope image clarity. The signal-to-noise ratio (SNR) is used to assess image signal quality, reflecting the ratio of signal intensity to noise intensity in the image. By analyzing the SNR under different ripple voltages, the degree of interference of high-voltage power supply ripple on image quality can be determined. Consequently, by fitting different ripple voltages to the corresponding resolution and SNR, corresponding mathematical models can be established to determine the impact of ripple on image resolution and SNR.

[0076] Step S203, determining the influence of voltage fluctuation on image stability based on comparative analysis of the quality of the image captured by the transmission electron microscope when using the standard high-voltage power supply and the high-voltage power supply to be tested within a preset time period, and obtaining a third influence result;

[0077] Specifically, the above step S203 includes:

[0078] Step S2031 : when a standard high voltage power supply is used, a plurality of first bright field images formed by a transmission electron microscope within a preset time period are acquired.

[0079] Step S2032 , calculating a first relationship between the drift amount and the resolution attenuation rate of the plurality of first bright field images and voltage fluctuation.

[0080] Step S2033 : when the high voltage power supply to be tested is used, a plurality of second bright field images formed by the transmission electron microscope within a preset time period are acquired.

[0081] Step S2034 , calculating a second relationship between the drift amount and the resolution attenuation rate of the plurality of second bright field images and the voltage fluctuation.

[0082] Step S2035: Obtain a third impact result according to the first relationship and the second relationship.

[0083] The preset duration can be a relatively long time, for example, eight hours or longer. While acquiring the first and second bright-field images, a bright-field image of a standard sample can also be acquired for analysis. Furthermore, because the bright-field images are acquired over a relatively long period of time, the acceleration voltage output by the high-voltage power supply may fluctuate during this extended period due to, for example, inherent stability issues. Therefore, the drift and resolution decay rate of the bright-field images acquired within the preset duration are analyzed to determine their impact with voltage fluctuations.

[0084] Specifically, the amount of drift can be determined using an image registration algorithm. The image registration algorithm can match brightfield images acquired at different times, find the positional changes of the same feature points in different images, and use this to calculate the amount of sample drift. Common methods include feature point matching, which first extracts feature points from each brightfield image, such as the corner points of the image, and then matches these feature points between different images. Based on the changes in the feature point coordinates, the relative displacement between images is calculated, and the amount of sample drift at different times is obtained. Alternatively, a grayscale correlation-based method can be used to calculate the grayscale similarity between images and find the translation, rotation, and other transformation parameters that maximize the grayscale correlation between the images to determine the amount of sample drift. For the resolution decay rate, the resolution of brightfield images acquired at different time points can be calculated, and then the resolution decay rate of the brightfield image can be calculated using the resolution at any time point and the resolution at the previous time point. In addition to calculating the drift and resolution at different time points, the acceleration voltage at different time points can also be recorded for subsequent analysis.

[0085] After obtaining the corresponding acceleration voltage, drift, and resolution decay rate for the standard high-voltage power supply and the high-voltage power supply to be tested, a corresponding relationship between the voltage fluctuation parameters and the image stability parameters (drift, resolution decay rate) can be established using the acquired data. This corresponding relationship can then be used to analyze the impact of voltage fluctuation on image stability. Specifically, the corresponding relationship obtained for the standard high-voltage power supply can be used as a reference quantity, and the corresponding relationship obtained for the high-voltage power supply to be tested can be compared with the reference quantity to further determine whether the high-voltage power supply to be tested meets the image stability requirements.

[0086] Step S204: Characterize the performance indicators of the high voltage power supply based on the first impact result, the second impact result, and the third impact result. Figure 1Step S104 of the illustrated embodiment will not be described in detail here.

[0087] As a specific application example of the embodiment of the present invention, Figure 2 As shown, the method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope can be implemented using the following process:

[0088] (1) Theoretical numerical simulation analysis.

[0089] The quantitative relationship between acceleration voltage and electron wavelength is determined based on the de Broglie formula, and the electron wavelength model is obtained.

[0090] The theoretical resolution limit of a transmission electron microscope is the resolution that only considers electron beam diffraction and the size limitation of the objective lens. According to the Abbe imaging principle and the Rayleigh criterion, the theoretical resolution limit formula is as follows:

[0091]

[0092] There is ripple in the voltage output by the DC high-voltage power supply. Based on the relationship between the acceleration voltage and the electron wavelength, the effect of the ripple on the electron wavelength is quantitatively analyzed. Based on the theoretical resolution limit, the influence of the ripple on the resolution of the transmission electron microscope is further derived.

[0093] In order to analyze the influence of ripple, a sinusoidal ripple signal U′=U is introduced. m sin(2πft), analyze the change in electron wavelength after superimposing the ripple:

[0094] Δλ=λ(U+U ′ )-λ(U)

[0095] When describing the stability of a high-voltage DC power supply, random processes are used to model the uncertainty and random fluctuations in the system. The high-frequency noise of a DC power supply can be approximated as Gaussian white noise, a random process with a normally distributed probability density function that can be used to describe random errors or irregularities in the output signal.

[0096] When performing stability analysis, random voltage fluctuations are simulated by Gaussian white noise, and the change in electron wavelength is calculated. According to the 3σ principle, a normal distribution with a specified standard deviation can be obtained:

[0097] σ=(10ppm×U) / 3

[0098] Convert the standard normal distribution Z~N(0,1) to a normal distribution with a specified mean and standard deviation, then the randomly fluctuating voltage value is:

[0099]

[0100] Electron wavelength changes:

[0101] Δλ=λ(U″)-λ(U)

[0102] (2) Performance verification method.

[0103] 1) Resolution test:

[0104] ① Use a standard sample to test on a transmission electron microscope, observe the bright field image of the sample (such as grid spacing, etc.), use the transmission electron microscope image analysis software to measure the grid spacing measurement value T, and calculate the magnification indication error △ and calibration coefficient η based on the standard value of the grid spacing T0.

[0105]

[0106] ② By artificially applying ripple to the high-voltage power supply, the bright field image of the standard sample under different ripple voltages is tested in situ. The resolution (lattice fringe spacing) and signal-to-noise ratio (SNR) are extracted using image processing software to analyze the influence of ripple on lattice resolution.

[0107] 2) Image stability test.

[0108] ① Use standard samples to observe for a long time on a transmission electron microscope, observe the bright field image of the sample (such as grid spacing, etc.), record the drift of the bright field image and the resolution decay rate, and analyze the impact of voltage fluctuations on the long-term stability of the image.

[0109] ② Replace the high-voltage power supply to be tested, such as a domestic high-voltage power supply, and conduct a long-term in-situ test in bright field imaging mode. Observe the bright field image of the sample, record the drift of the bright field image and the resolution attenuation rate, and analyze the impact of voltage fluctuations on the long-term stability of the image.

[0110] As a specific application example of the present invention, the method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope can be implemented using the following process:

[0111] (1) Theoretical numerical simulation analysis.

[0112] According to the de Broglie formula, the electron wavelength is inversely proportional to the square root of the acceleration voltage of the high-voltage power supply. The higher the acceleration voltage, the shorter the electron wavelength and the higher the resolution. Taking the acceleration voltage of 0-100kV, the relationship curve between the electron wavelength and the acceleration voltage is as follows: Figure 3 shown.

[0113] There is ripple in the voltage output by the DC high-voltage power supply. Based on the relationship between the acceleration voltage and the electron wavelength, the effect of ripple on the electron wavelength is quantitatively analyzed. The influence of ripple on the resolution of the transmission electron microscope is further derived through resolution calculation.

[0114] Assume that the acceleration voltage is 100kV and the applied ripple signal is a sine wave. Its amplitude U mThe order is: 20mV, 70mV, 100mV, 200mV, 300mV, 400mV, 500mV, 600mV, 700mV, 800mV, 900mV, 1000mV; the ripple frequency f is 20kHz. Introduce a sinusoidal ripple signal U′=U m sin(2πft), then the electron wavelength changes with time under different ripples as follows Figure 4 As shown in Figure 2, the effect of a 70mV ripple signal on the electron beam wavelength is on the picometer level. Therefore, theoretically, the effect of the high-voltage power supply ripple signal on the resolution of electron beam-based instruments can be ignored.

[0115] When describing the stability of a high-voltage DC power supply, random processes are often used to model the uncertainty and random fluctuations in the system. The high-frequency noise of a DC power supply can be approximated as Gaussian white noise, a random process with a normally distributed probability density function that can be used to describe random errors or irregularities in the output signal.

[0116] Assuming that the applied acceleration voltage U is: 10kV, 30kV, 50kV, 80kV, 100kV, and the voltage stability is ≤10ppm, the change of electron wavelength with time is as follows: Figure 5 The influence of voltage stability on electron wavelength is on the order of picometers, so theoretically, fluctuations in the stability of the high-voltage power supply have a negligible effect on the resolution of electron beam-based instruments.

[0117] (2) Performance verification method.

[0118] A transmission electron microscope and a self-developed -100kV high-voltage power supply were used to calibrate the equipment to the standard working state.

[0119] Install the standard sample (such as Au single crystal thin film) on the transmission electron microscope sample stage to ensure that the vacuum system is in working condition.

[0120] 1) Resolution test:

[0121] ① Use a standard sample to test on a transmission electron microscope, observe the bright field image of the sample (such as grid spacing, etc.), use the transmission electron microscope image analysis software to measure the grid spacing measurement value T, and calculate the magnification indication error △ and calibration coefficient η based on the standard value of the grid spacing T0.

[0122] ② By artificially applying ripple to the high-voltage power supply, the bright field image of the standard sample under different acceleration voltages and ripple voltages is tested in situ. The resolution (lattice fringe spacing) and signal-to-noise ratio (SNR) are extracted using image processing software, and the influence of ripple on lattice resolution is analyzed.

[0123] 2) Image stability test:

[0124] ① Long-term observations were performed on a transmission electron microscope using a standard sample. Brightfield images were collected every 30 minutes for 8 hours. Sample drift was calculated using an image registration algorithm, and a drift-time curve was generated. The drift and resolution decay of the brightfield image were recorded, and the impact of voltage fluctuations on the long-term image stability was analyzed.

[0125] ② Replace the power supply with a domestically produced high-voltage power supply and conduct long-term in-situ testing in brightfield imaging mode. Brightfield images are collected every 30 minutes for 8 hours. Sample drift is calculated using an image registration algorithm, and a drift-time curve is generated. The drift and resolution decay of the brightfield images are recorded, and the impact of voltage fluctuations on long-term image stability is analyzed.

[0126] This paper uses theoretical numerical simulation to analyze the impact of high-voltage power supply parameters such as ripple and stability on key transmission electron microscope parameters (resolution and image stability). By artificially applying controllable ripple and combining it with quantitative analysis of brightfield image resolution and image drift, a direct correlation between high-voltage power supply performance and transmission electron microscope imaging quality is established. This provides technical support for the design optimization of domestic high-voltage power supplies and the verification of electron microscope compatibility. This has promoted the demonstration application of domestic high-voltage power supplies in domestic transmission electron microscopes.

[0127] In this embodiment, a device for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope is also provided. This device is used to implement the above-mentioned embodiments and preferred embodiments, and the details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that implements a predetermined function. Although the devices described in the following embodiments are preferably implemented in software, implementation using hardware, or a combination of software and hardware, is also possible and contemplated.

[0128] This embodiment provides a device for in-situ verification of performance indicators of a high voltage power supply in a transmission electron microscope, such as Figure 6 Shown, including:

[0129] Theoretical analysis module 61 is used to determine the influence of ripple and noise in the acceleration voltage output by the high-voltage power supply on the electron wavelength and resolution based on the electron wavelength model and the resolution model, and obtain a first influence result;

[0130] A resolution analysis module 62 is configured to determine, based on the quality of an image formed by a transmission electron microscope and the presence of different ripples in the accelerating voltage output by the high-voltage power supply, an influence rule of the ripples on the image resolution, and obtain a second influence result;

[0131] a stability analysis module 63 for determining the influence of voltage fluctuation on image stability based on comparative analysis of the quality of images generated by the transmission electron microscope when using a standard high-voltage power supply and a high-voltage power supply to be tested within a preset time period, thereby obtaining a third influence result;

[0132] The performance characterization module 64 is configured to characterize the performance indicators of the high-voltage power supply based on the first impact result, the second impact result, and the third impact result.

[0133] The further functional description of each of the above modules is the same as that of the above corresponding embodiments and will not be repeated here.

[0134] The embodiment of the present invention also provides a computer device having the above Figure 6 The device shown is used to verify the performance indicators of the high-voltage power supply in situ in the transmission electron microscope.

[0135] See also Figure 7 , Figure 7 is a structural diagram of a computer device provided by an optional embodiment of the present invention, such as Figure 7 As shown, the computer device includes: one or more processors 10, memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components utilize different buses to communicate with each other and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in the memory or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Equally, multiple computer devices can be connected, and each device provides part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Figure 7 A processor 10 is taken as an example.

[0136] The processor 10 may be a central processing unit, a network processor, or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic, or any combination thereof.

[0137] The memory 20 stores instructions that can be executed by at least one processor 10, so as to enable at least one processor 10 to execute the method shown in the above embodiment.

[0138] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created based on the use of a computer device for displaying a small program landing page, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0139] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0140] The computer device further includes a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0141] The embodiment of the present invention also provides a computer-readable storage medium. The above-mentioned method according to the embodiment of the present invention can be implemented in hardware, firmware, or implemented as a computer code that can be recorded in a storage medium, or implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and downloaded through a network and will be stored in a local storage medium, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state drive, etc.; further, the storage medium can also include a combination of the above-mentioned types of memory. It can be understood that a computer, a processor, a microprocessor controller or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0142] A portion of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the form in which the computer program instruction exists in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc. Accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium that can be accessed by the computer.

[0143] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope, characterized in that: The method comprises: Based on the electron wavelength model and resolution model, the influence of ripple and noise in the acceleration voltage output by the high-voltage power supply on the electron wavelength and resolution is determined, and the first influence result is obtained; Based on the quality of the transmission electron microscope image when the accelerating voltage output by the high-voltage power supply contains different ripples, the influence of the ripple on the image resolution is determined to obtain the second influence result; Based on a comparative analysis of the quality of the image captured by the transmission electron microscope when using a standard high-voltage power supply and a high-voltage power supply to be tested within a preset time period, the influence of voltage stability on image stability is determined, and a third influence result is obtained; Based on the first impact result, the second impact result, and the third impact result, performance indicators of the high-voltage power supply are characterized.

2. The method according to claim 1, characterized in that Based on the electron wavelength model and the resolution model, determining the influence of ripple and noise on the electron wavelength and resolution when the accelerating voltage output by the high-voltage power supply is present, before obtaining the first influence result, the method further includes: Based on the de Broglie formula, the relationship between the accelerating voltage output by the high-voltage power supply and the electron wavelength of the electron beam output by the transmission electron microscope is determined to obtain an electron wavelength model; Based on the Abbe imaging principle and the Rayleigh criterion, the theoretical resolution limit of the lens electron microscope is determined, and a resolution model is obtained. The resolution model includes the relationship between electron wavelength and resolution.

3. The method according to claim 1, characterized in that Based on the electron wavelength model and resolution model, the influence of ripple and noise in the accelerating voltage output by the high-voltage power supply on the electron wavelength and resolution is determined, and the first impact results are obtained, including: Determining, based on an electron wavelength model, a first change in electron wavelength when different ripple signals are superimposed on the acceleration voltage; Based on the first change of electron wavelength and resolution model, the influence of ripple on resolution is determined; A random process is used to simulate the fluctuation of the accelerating voltage when noise exists, and the randomly fluctuating voltage value is obtained; determining a second change in the electron wavelength based on the electron wavelength model and the randomly fluctuating voltage value; Based on the second change of electron wavelength and the resolution model, the influence of fluctuation of acceleration voltage on resolution in the presence of noise is determined.

4. The method according to claim 1, wherein Based on the quality of the transmission electron microscope image when the accelerating voltage output by the high-voltage power supply contains different ripples, the influence of the ripple on the image resolution is determined, and the second impact result is obtained, including: Apply different ripple signals to the accelerating voltage output by the high-voltage power supply, and in-situ test the bright field image of the standard sample formed under the transmission electron microscope under different ripple signals; The resolution and signal-to-noise ratio of the bright field image corresponding to different ripple signals are calculated to obtain a second impact result.

5. The method according to claim 4, characterized in that Before applying different ripple signals to the accelerating voltage output by the high-voltage power supply and in-situ testing the bright field images formed by the transmission electron microscope under the different ripple signals, the method further includes: Obtain a bright field image of the standard sample formed by a transmission electron microscope; Calculate the indication error and calibration coefficient of the bright field image.

6. The method according to claim 1, wherein Based on a comparative analysis of the quality of transmission electron microscope images when using a standard high-voltage power supply and a high-voltage power supply to be tested within a preset time, the influence of voltage stability on image stability is determined, and the third impact result is obtained, including: When a standard high-voltage power supply is used, a plurality of first bright-field images formed by a transmission electron microscope within a preset time period are acquired; Calculating a first relationship between a drift amount and a resolution decay rate of a plurality of first bright field images and voltage fluctuation; When the high voltage power supply to be tested is used, a plurality of second bright field images formed by the transmission electron microscope within a preset time period are acquired; calculating a second relationship between the drift amount and the resolution decay rate of the plurality of second bright field images and voltage fluctuation; A third impact result is obtained according to the first relationship and the second relationship.

7. The method according to claim 1, wherein: The electron wavelength model is expressed by the following formula: Where λ represents the electron wavelength and U represents the accelerating voltage; The resolution model is expressed by the following formula: Where r represents the theoretical resolution limit and β represents the collection angle of the objective lens.

8. A device for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope, characterized in that: The device comprises: A theoretical analysis module is used to determine the influence of ripple and noise in the acceleration voltage output by the high-voltage power supply on the electron wavelength and resolution based on the electron wavelength model and the resolution model, and obtain a first influence result; A resolution analysis module is used to determine the influence of ripple on image resolution based on the quality of the image of the transmission electron microscope when the acceleration voltage output by the high-voltage power supply contains different ripples, and obtain a second influence result; a stability analysis module for determining the influence of voltage stability on image stability based on comparative analysis of the quality of images generated by the transmission electron microscope when using a standard high-voltage power supply and a high-voltage power supply to be tested within a preset time period, thereby obtaining a third influence result; A performance characterization module is used to characterize the performance indicators of the high-voltage power supply based on the first impact result, the second impact result and the third impact result.

9. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope according to any one of claims 1 to 7 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, which are used to enable a computer to execute the method for in-situ verification of performance indicators of a high-voltage power supply in a transmission electron microscope according to any one of claims 1 to 7.

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