Method for reducing fluctuation of spectrum acquisition efficiency of galvanometer FL-LIBS system

Abstract

The invention relates to the technical field of spectral analysis, and relates to a method for reducing fluctuation of spectrum acquisition efficiency of a galvanometer FL-LIBS system. The method comprises the following steps: acquiring efficiency curved surface information; for each target spectral line, determining a mapping relationship between the wavelength and the curved surface parameter according to the wavelength of the target spectral line and the curved surface parameter; obtaining target spectral information; for each to-be-measured spectral line, determining a target curved surface parameter according to the wavelength of the to-be-measured spectral line and the mapping relation, determining a target efficiency curved surface based on the target curved surface parameter and each position point, and determining the correction intensity of the to-be-measured spectral line according to the measurement intensity of the to-be-measured spectral line at the selected position point and the target efficiency curved surface, therefore, quantitative analysis can be carried out on the to-be-detected sample according to the correction intensity of each to-be-detected spectral line. According to the method provided by the invention, the problem that the spectrum intensity is not real due to the fact that the acquisition efficiency of an acquisition system fluctuates due to factors such as dispersion can be solved, and the problems of weak spectrum stability and low analysis accuracy in the prior art are solved.

Description

Technical Field

[0001] This application relates to the technical field of spectral analysis, and in particular, to a method for reducing the fluctuation of the spectral acquisition efficiency of a galvanometer FL-LIBS system. Background Art

[0002] Laser Induced Breakdown Spectroscopy (LIBS) is an atomic emission spectroscopy technique. Its basic principle is to focus a laser on the surface of a sample to be analyzed to generate a plasma, and then obtain the types and content information of elements inside the sample by collecting and analyzing the spectrum generated by the plasma. LIBS technology has the advantages of being able to detect all elements, being almost non-destructive, in-situ, fast, and applicable to solid, liquid, and gaseous states, so it is widely used for element detection in various fields. The LIBS technology using a fiber laser as the excitation source is called FL-LIBS (Laser Induced Breakdown Spectroscopy based on Fiber Laser ablation), which has the advantages of faster acquisition speed, stable light output, and simple light source thermal management.

[0003] Introducing a galvanometer into the FL-LIBS system has unique advantages when collecting spectra of large-range and large-weight samples. In addition, due to the extremely fast scanning speed, ultra-high-speed spectral acquisition can be achieved. However, the galvanometer needs to be used with a field lens, and the presence of the field lens will cause fluctuations in the spectral acquisition efficiency of the system. The specific manifestations are as follows: Due to the existence of factors such as dispersion in the optical system, the spectra collected at different positions on the surface of a sample with the same element distribution being ablated are very different. And the most basic principle of LIBS is that the spectral intensity reflects the element content. For the spectra obtained by the galvanometer FL-LIBS, the element distribution cannot be correctly reflected, which is not conducive to the final qualitative or quantitative analysis of elements.

[0004] In view of the above defects and deficiencies, there is an urgent need for a method to improve and perfect it. Since factors such as dispersion in the optical system objectively exist and cannot be avoided, it is necessary to design a method for reducing the fluctuation of the spectral acquisition efficiency of the galvanometer FL-LIBS, so as to improve the stability of the spectra collected by the galvanometer FL-LIBS system, enable the collected spectra to correctly reflect the two-dimensional surface distribution of elements, and improve the accuracy of galvanometer FL-LIBS analysis. Summary of the Invention

[0005] This application provides a method for reducing the fluctuation of the spectral acquisition efficiency of a galvanometer FL-LIBS system to solve one or more technical problems existing in the prior art, and at least provides a beneficial choice or creation condition.

[0006] Other features and advantages of the present application will become apparent from the following detailed description, or will be learned in part through the practice of the present application.

[0007] According to one aspect of the embodiments of the present application, a method for reducing the spectral acquisition efficiency fluctuation of a galvanometer FL-LIBS system is provided, which is applied to an acquisition system for scanning a sample to be measured or a standard sample in an acquisition area. The method includes:

[0008] Obtain the efficiency surface information obtained by scanning and collecting the standard sample by the acquisition system. The efficiency surface information includes the efficiency surfaces of multiple target spectral lines, and each efficiency surface is used to characterize the acquisition efficiency corresponding to each position point in the acquisition area of the acquisition system;

[0009] For each of the target spectral lines, determine the mapping relationship between the wavelength and the surface parameters according to the wavelength of the target spectral line and the surface parameters of the efficiency surface corresponding to the target spectral line;

[0010] Obtain the target spectral information obtained by scanning and collecting the sample to be measured by the acquisition system. The target spectral information includes the spectral information collected by the acquisition system at each of the position points, and each spectral information includes multiple spectral lines to be measured and the measurement intensities of each of the spectral lines to be measured;

[0011] For each of the spectral lines to be measured, determine the target surface parameters of the spectral line to be measured according to the wavelength of the spectral line to be measured and the mapping relationship, and determine the target efficiency surface of the spectral line to be measured based on the target surface parameters, and determine the corrected intensity of the spectral line to be measured according to the measurement intensity of the spectral line to be measured at the selected position point and the target efficiency surface, so as to perform quantitative analysis on the sample to be measured according to the corrected intensities of each of the spectral lines to be measured.

[0012] In an embodiment of the present application, based on the foregoing solution, the obtaining the efficiency surface information obtained by scanning and collecting the standard sample by the acquisition system includes:

[0013] Perform scans of the standard sample for a target number of rounds to obtain multiple sets of scan information corresponding to the target number. Each set of scan information includes standard spectral information corresponding one-to-one to each of the position points, and each standard spectral information includes the intensity position distribution information of each of the target spectral lines;

[0014] For each of the position points, take the average of the intensity position distribution information of each of the target spectral lines in each set of scan information according to the target number to obtain the target intensity of each of the target spectral lines;

[0015] For each of the target spectral lines, select the position point with the maximum target intensity among the target intensities corresponding to each of the position points as the target position point, mark the acquisition efficiency of the target position point as one, and perform normalization processing on each of the position points according to the target intensities of each of the position points to obtain the acquisition efficiency of each of the position points, and determine the efficiency surface of the target spectral line according to each of the acquisition efficiencies;

[0016] Determine the efficiency surface information according to the efficiency surfaces of each of the target spectral lines.

[0017] In an embodiment of the present application, based on the foregoing solution, the surface parameters of the efficiency surface include a first surface parameter, a second surface parameter, a third surface parameter, and a fourth surface parameter. The determining the mapping relationship between the wavelength and the surface parameters according to the wavelength of the target spectral line and the surface parameters of the efficiency surface corresponding to the target spectral line includes:

[0018] Input the wavelength of the target spectral line into a preset fitting calculation formula to obtain the first surface parameter, the second surface parameter, the third surface parameter, and the fourth surface parameter of the efficiency surface corresponding to the target spectral line, so as to determine the mapping relationship between the wavelength and the surface parameters;

[0019] Wherein, the fitting calculation formula is applicable to each of the target spectral lines or each of the to-be-detected spectral lines.

[0020] In an embodiment of the present application, based on the foregoing solution, the determining the target surface parameters of the to-be-detected spectral line according to the wavelength of the to-be-detected spectral line and the mapping relationship includes:

[0021] According to the mapping relationship, input the wavelength of the to-be-detected spectral line into the fitting calculation formula to obtain the target surface parameters of the to-be-detected spectral line;

[0022] Wherein, the target surface parameters include a first target surface parameter, a second target surface parameter, a third target surface parameter, and a fourth target surface parameter.

[0023] In an embodiment of the present application, based on the foregoing solution, the determining the target efficiency surface of the to-be-detected spectral line based on the target surface parameters includes:

[0024] Determine the target efficiency surface of the to-be-detected spectral line according to the first target surface parameter, the second target surface parameter, the third target surface parameter, and the fourth target surface parameter, so as to determine the acquisition efficiency of each of the position points according to the target efficiency surface.

[0025] In an embodiment of the present application, based on the foregoing solution, determining the corrected intensity of the to-be-detected spectral line according to the measured intensity of the to-be-detected spectral line at the selected position point and the target efficiency surface includes:

[0026] Obtaining the target acquisition efficiency corresponding to the selected position point according to the target efficiency surface;

[0027] Dividing the measured intensity by the target acquisition efficiency to obtain the corrected intensity of the to-be-detected spectral line.

[0028] The principle of the present application is as follows: The acquisition system, that is, the galvanometer FL-LIBS system mentioned in the background art, collects the efficiency surface information of the standard sample in the acquisition area through this acquisition system. The efficiency surface information includes the efficiency surfaces of multiple target spectral lines. Each efficiency surface represents the acquisition efficiency corresponding to each position point in the acquisition area. There is also a mapping relationship between the wavelength of the spectral line and the surface parameters of the efficiency surface. That is, the correlation between the position point and the spectral line can be established through the efficiency surface, that is, the acquisition efficiency is related to the position point collected by the acquisition system.

[0029] By analyzing the standard sample, the spectral line intensity of each spectral line at different position points can be obtained, and the acquisition efficiency corresponding to each position point in the acquisition area of the acquisition system can be deduced therefrom. The acquisition efficiency is also related to the wavelength of the spectral line. Since the mapping relationship between the wavelength and the surface parameters has been established through the efficiency surface above, then only by the wavelength of the to-be-detected spectral line and this mapping relationship can the target surface parameters of the to-be-detected spectral line be obtained. Through the target surface parameters, the target efficiency surface can be generated, that is, it represents the acquisition efficiency corresponding to each position point of the to-be-detected spectral line.

[0030] In the actual acquisition process of the acquisition system, the spectral information of the selected position point is collected. From this spectral information, the measured intensity of each to-be-detected spectral line at the selected position point can be known, and then the corrected intensity of the to-be-detected spectral line can be determined through the measured intensity and the target efficiency surface of the to-be-detected spectral line. After the corrected intensity of each to-be-detected spectral line is calculated, quantitative analysis of the to-be-detected sample can be performed.

[0031] The beneficial effect of the present application is that by determining the acquisition efficiency at different position points, the corrected intensity of each to-be-detected spectral line in the spectral information corresponding to this position point can be known, and quantitative analysis of the to-be-detected sample can be performed thereby, improving the accuracy of quantitative analysis, and overcoming the problem of untrue spectral intensity caused by fluctuations in acquisition efficiency due to factors such as dispersion in the acquisition system, and solving the problems and pain points of weak spectral stability and low analysis accuracy in the prior art.

[0032] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and for those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. In the drawings:

[0034] Figure 1 FIG. is a flowchart of a method for reducing the fluctuation of the spectral acquisition efficiency of a galvanometer FL-LIBS system according to an embodiment of the present application;

[0035] Figure 2 FIG. is a schematic diagram of an efficiency surface or a target efficiency surface according to an embodiment of the present application;

[0036] Figure 3 FIG. is a fitting relationship diagram of wavelength and parameter ω1 according to an embodiment of the present application;

[0037] Figure 4 FIG. is a fitting relationship diagram of wavelength and parameter ω2 according to an embodiment of the present application;

[0038] Figure 5 FIG. is a fitting relationship diagram of wavelength and parameter x c according to an embodiment of the present application;

[0039] Figure 6 FIG. is a fitting relationship diagram of wavelength and parameter y c according to an embodiment of the present application;

[0040] Figure 7 FIG. is a schematic diagram of a planar scanning area according to the present application. DETAILED DESCRIPTION

[0041] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this application will be more complete and comprehensive, and will fully convey the concept of the example embodiments to those skilled in the art.

[0042] In addition, the described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, numerous specific details are provided to give a thorough understanding of the embodiments of the present application. However, those skilled in the art will realize that the technical solutions of the present application may be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the present application.

[0043] The block diagrams shown in the drawings are only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software form, or implemented in one or more hardware modules or integrated circuits, or implemented in different networks and / or processor devices and / or micro-control node devices.

[0044] The flowcharts shown in the drawings are only illustrative and do not necessarily include all the content and operations / steps, nor are they necessarily executed in the described order. For example, some operations / steps may be decomposed, while some operations / steps may be combined or partially combined, so the actual execution order may change according to the actual situation.

[0045] It should be noted that: "a plurality of" mentioned in this article refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0046] The following provides a detailed introduction to the logical principle of the present application:

[0047] First, the acquisition system mentioned in the present application is the galvanometer FL-LIBS system mentioned in the background art. The acquisition system can move to a certain position point within the acquisition area for spectral acquisition. The spectral information obtained by the acquisition contains multiple spectral lines and the measured intensity of each spectral line. However, due to the factors such as dispersion existing in the optical system mentioned in the background art, the measured intensity of the spectral line is not the true intensity. At this time, the present application introduces the acquisition efficiency to reflect the connection between the measured intensity and the true intensity.

[0048] Meanwhile, the acquisition efficiency of the acquisition system varies at different position points. For example, during the acquisition of spectral information of a standard sample (i.e., a pure sample without interference from other elements), the measured intensities of a certain spectral line at position point A and position point B are 800 and 1000 respectively. Therefore, the acquisition efficiency is different at different position points within the acquisition area. It should be noted that the standard sample is pure titanium as an example without interference from other elements, so the acquisition efficiency at different position points will not be affected by other elements (spectral lines) either. In this way, the correlation between different position points and the acquisition efficiency is established.

[0049] By performing a spectral acquisition on each acquisition point (i.e., each position point) within the acquisition area, the measured intensities of each spectral line (only a part of the spectral lines are selected as target spectral lines for analysis in this application) can be obtained. Taking a certain target spectral line as an example, in this application, the position point with the maximum measured intensity (i.e., the target intensity of the target spectral line described in this application) is used as the target position point. At this time, the acquisition efficiency is the highest. That is, the target intensities of each position point are normalized with the acquisition efficiency of the target position point being 1, and the acquisition efficiency of each position point is obtained through proportional conversion to generate an efficiency surface (the efficiency surface actually represents the acquisition efficiency corresponding to each position point). It should be noted that the efficiency surfaces of each target spectral line are different. For example, the acquisition efficiency of target spectral line a at position point A is 0.9, and at position point B is 0.8; however, the acquisition efficiency of target spectral line b at position point A is 0.85, and at position point B is 0.7. In this way, corresponding efficiency surfaces are generated according to different target spectral lines (i.e., the target spectral lines are identified according to their wavelengths).

[0050] In the actual spectral acquisition of the sample to be measured, since different spectral lines to be measured are distinguished by their wavelengths. For example, the wavelength of the spectral line to be measured c is 430.04 nm, and the wavelength of the spectral line to be measured d is 450.13 nm. Then, as long as we know the wavelength of the spectral line, we know the information of the spectral line. Among the target spectral information of the sample to be measured obtained by acquisition, it also contains the spectral information of each position point, that is, the measured intensities of each spectral line to be measured at the corresponding position points can be known from the spectral information (the measured intensities at this time are also inaccurate and need to be calculated to obtain the corrected intensity through the acquisition efficiency).

[0051] Then the acquisition efficiency can be determined by the wavelength of the spectral line to be measured. Since the mapping relationship between the wavelength and the surface parameters can be obtained from the analysis of the standard sample, this mapping relationship can be reflected by a fitting calculation formula, which can be applied to the efficiency surface or the target efficiency surface. Through this fitting calculation formula, the acquisition efficiency of the spectral line to be measured at a certain position point can be obtained. Furthermore, the acquisition efficiency of each spectral line to be measured can be obtained. When the acquisition system performs spectral acquisition at the selected position point, the corrected intensity of the spectral line to be measured can be obtained by simply dividing the measured intensity of the spectral line to be measured at the selected position point by the acquisition efficiency corresponding to the selected position point. After the corrected intensity of each spectral line to be measured is calculated, quantitative analysis of the sample to be measured can be carried out.

[0052] According to one aspect of the present application, a method for reducing the fluctuation of the spectral acquisition efficiency of a galvanometer FL-LIBS system is provided. Figure 1 FIG. is a flowchart of a method for reducing the fluctuation of the spectral acquisition efficiency of a galvanometer FL-LIBS system according to an embodiment of the present application. The method for reducing the fluctuation of the spectral acquisition efficiency of a galvanometer FL-LIBS system at least includes steps S1 to S5, which are introduced in detail as follows:

[0053] In step S1, the efficiency surface information obtained by the acquisition system scanning and acquiring the standard sample is obtained. The efficiency surface information includes the efficiency surfaces of multiple target spectral lines, and each efficiency surface is used to characterize the acquisition efficiency corresponding to each position point in the acquisition area of the acquisition system.

[0054] First of all, it should be noted that the wavelength of the target spectral line is known, and the information that can be obtained from the efficiency surface is: the acquisition efficiency of each position point. The preparatory work for obtaining the efficiency surface includes: setting galvanometer scanning parameters, laser parameters, spectrometer acquisition parameters, synchronization module parameters, etc., opening the serial port, placing the pure sample in the scanning plane, and adjusting the sample surface to be horizontal.

[0055] Spectrum and position acquisition: The spectrometer, the synchronization module, and the laser galvanometer scanning are sequentially turned on to obtain position information and spectrum information, where the position information and the spectrum information constitute the scanning information in the present application.

[0056] Efficiency surface spectrum and position information fusion: Select N spectral lines (corresponding to N efficiency surfaces, N is exemplarily 12 in the present application) as the target spectral lines λ n (n = 1, 2, 3... N) at intervals along the wavelength. The x and y coordinates reflecting the position information (corresponding to the position points in the present application) and the target intensity of the target spectral lines are put into one-to-one correspondence to obtain N position intensity distribution maps (i.e., the efficiency surfaces in the present application), and the intensity distribution I n (λ n, x, y)(n = 1, 2, 3…N). The intensity position distribution information diagram (i.e., the efficiency surface of the present application) can be as Figure 2 shown. In the figure, Efficiency represents the acquisition efficiency.

[0057] In an embodiment of the present application, obtaining the efficiency surface information obtained by scanning and collecting the standard sample by the acquisition system includes:

[0058] Scanning the standard sample for a target number of rounds to obtain multiple groups of scanning information corresponding to the target number. Each group of scanning information includes standard spectral information corresponding one-to-one to each position point. Each standard spectral information includes the intensity position distribution information of each target spectral line;

[0059] For each position point, respectively take the average of the intensity position distribution information of each target spectral line in each group of scanning information according to the target number to obtain the target intensity of each target spectral line;

[0060] For each target spectral line, select the position point with the maximum target intensity among the target intensities corresponding to each position point as the target position point, mark the acquisition efficiency of the target position point as one, and perform normalization processing on each position point according to the target intensity of each position point to obtain the acquisition efficiency of each position point, and determine the efficiency surface of the target spectral line according to the acquisition efficiency of each position point;

[0061] Determine the efficiency surface information according to the efficiency surfaces of each target spectral line.

[0062] Specifically, to avoid contingency, scan the standard sample k times to obtain k groups of scanning information (including position information and spectral information), and take the average of the nth (n = 1, 2, 3…N) spectral line in each group of scanning information. There is That is to say, the spectral line intensity of the target spectral line corresponding to each position point is collected k times, and it is necessary to take the average of the k spectral line intensities obtained by k acquisitions, which represents the target intensity of the target spectral line to be measured at this position point. Finally, in take the maximum value as the denominator for normalization to obtain the efficiency distribution E n (λ n , x, y)(n = 1, 2, 3…N). It should be noted that taking the maximum value is to compare the target intensities of the spectral line to be measured at each position point, select the position point with the maximum intensity as the target position point, mark the acquisition efficiency of the position point at this time as one, and then perform normalization processing to obtain the efficiency distribution of each position point. Then from E n (λ n, x, y) (n = 1, 2, 3…N), we can obtain the acquisition efficiency corresponding to any target spectral line at any position point.

[0063] In step S2, for each of the target spectral lines, a mapping relationship between the wavelength and the surface parameters is determined according to the wavelength of the target spectral line and the surface parameters of the efficiency surface corresponding to the target spectral line.

[0064] The surface parameters of the efficiency surface include a first surface parameter, a second surface parameter, a third surface parameter, and a fourth surface parameter. Determining the mapping relationship between the wavelength and the surface parameters according to the wavelength of the target spectral line and the surface parameters of the efficiency surface corresponding to the target spectral line includes:

[0065] Inputting the wavelength of the target spectral line into a preset fitting calculation formula to obtain the first surface parameter, the second surface parameter, the third surface parameter, and the fourth surface parameter of the efficiency surface corresponding to the target spectral line, so as to determine the mapping relationship between the wavelength and the surface parameters;

[0066] Among them, the fitting calculation formula is applicable to each of the target spectral lines or each of the spectral lines to be measured.

[0067] Specifically, the fitting calculation formula can be specifically:

[0068]

[0069] Where λ represents the wavelength of the target spectral line or the spectral line to be measured, x and y represent the plane coordinates of the position point, ω1 and ω2 respectively represent the first surface parameter (i.e., the full width at half maximum in the x direction) and the second surface parameter (i.e., the full width at half maximum in the y direction), and x c and y c respectively represent the third surface parameter and the fourth surface parameter. That is to say, x c and y c constitute the center coordinates of the efficiency surface. It should be noted that the relationship between ω1, ω2 and the wavelength is obtained through quadratic fitting, and x c and y c are obtained through linear fitting. The fitting relationships of the four parameters with the wavelength can be as Figures 3 - 6 shown, where in Figures 3 - 6 Wavelength represents the wavelength. The fitting calculation formula is applicable to each of the target spectral lines or each of the spectral lines to be measured, and ω1, ω2, x c and y c also respectively represent the first target surface parameter, the second target surface parameter, the third target surface parameter, and the fourth target surface parameter. Generally speaking, through the wavelength of the spectral line to be measured and the mapping relationship (see Figures 3 - 6)The first target surface parameter, the second target surface parameter, the third target surface parameter, and the fourth target surface parameter can be obtained.

[0070] Furthermore, input the first target surface parameter, the second target surface parameter, the third target surface parameter, and the fourth target surface parameter into the fitting calculation formula, and then the target efficiency surface related to each position point can be obtained. In the target efficiency surface, the coordinates x and y of the position point are variables, and thus the acquisition efficiency corresponding to each position point can be known.

[0071] Furthermore, determining the target efficiency surface of the to-be-detected spectral line based on the target surface parameter includes:

[0072] Determine the target efficiency surface of the to-be-detected spectral line according to the first target surface parameter, the second target surface parameter, the third target surface parameter, and the fourth target surface parameter, so as to determine the acquisition efficiency of each position point according to the target efficiency surface.

[0073] Specifically, for each position point, since the first target surface parameter, the second target surface parameter, the third target surface parameter, the fourth target surface parameter, and the wavelength of the to-be-detected spectral line have been known through the above steps, at this time, only need to input the position point corresponding to the to-be-detected spectral line into the fitting calculation formula, and then the acquisition efficiency of the acquisition system at the position point can be obtained.

[0074] By calculating the acquisition efficiency of each position point, a target efficiency surface can be generated, expressed as E(λ i ,x,y), that is, the acquisition efficiency of any to-be-detected spectral line at any position point can be known from E(λ i ,x,y).

[0075] In step S3, obtain the target spectral information collected by the acquisition system for scanning and collecting the to-be-detected sample. The target spectral information includes the spectral information collected by the acquisition system at each position point, and each spectral information includes multiple to-be-detected spectral lines and the measurement intensities of each to-be-detected spectral line.

[0076] Specifically, in the actual spectral acquisition of the to-be-detected sample, since different to-be-detected spectral lines are distinguished by their wavelengths. For example, the wavelength of the to-be-detected spectral line c is 430.04 nm, and the wavelength of the to-be-detected spectral line d is 450.13 nm. Then, as long as we know the wavelength of the spectral line, we know the information of the spectral line. And in the target spectral information of the to-be-detected sample collected, it also contains the spectral information of each position point, that is, the measurement intensities of each to-be-detected spectral line corresponding to the position point can be known from the spectral information (at this time, the measurement intensity is also inaccurate and needs to be calculated by the acquisition efficiency to obtain the corrected intensity).

[0077] In step S4, for each of the to-be-tested spectral lines, determine the target surface parameters of the to-be-tested spectral line according to the wavelength of the to-be-tested spectral line and the mapping relationship, determine the target efficiency surface of the to-be-tested spectral line based on the target surface parameters, and determine the corrected intensity of the to-be-tested spectral line according to the measured intensity of the to-be-tested spectral line at the selected position point and the target efficiency surface, so as to perform quantitative analysis on the to-be-tested sample according to the corrected intensities of the to-be-tested spectral lines.

[0078] In an embodiment of the present application, the determining the corrected intensity of the to-be-tested spectral line according to the measured intensity of the to-be-tested spectral line at the selected position point and the target efficiency surface includes:

[0079] Obtain the target acquisition efficiency corresponding to the selected position point according to the target efficiency surface;

[0080] Divide the measured intensity by the target acquisition efficiency to obtain the corrected intensity of the to-be-tested spectral line.

[0081] Specifically, the target acquisition efficiency of any to-be-tested spectral line at any position point can be obtained from E(λ i , x, y). And the measured intensity corresponding to the to-be-tested spectral line at the selected position point can be obtained according to the wavelength of the to-be-tested spectral line. Divide the measured intensity by the target acquisition efficiency to obtain the corrected intensity of the to-be-tested spectral line. After calculating the corrected intensities of the to-be-tested spectral lines, quantitative analysis can be performed on the to-be-tested sample according to the theoretical knowledge of the spectrum.

[0082] The following is an exemplary description of the specific implementation:

[0083] S101, select pure titanium as the standard sample for obtaining the efficiency surface.

[0084] S102, select a high-repetition-rate pulsed fiber laser as the laser, and some of its parameters are: pulse width 123 ns, pulse repetition frequency 30 kHz, and laser power 30.2 W. Select the 425.46 nm spectral line of Cr element as the spectral line to be analyzed.

[0085] S103, set the galvanometer scanning parameters, laser parameters, spectrometer acquisition parameters, and synchronization module parameters. The scanning area range is -18.5 to 18.5 mm in the x direction and -18.5 to 18.5 mm in the y direction. As Figure 7 shown in the area, the scanning path length is 37 mm, the scanning direction is one-way scanning, and place the pure titanium sample in the efficiency surface area (i.e., the acquisition area described in the present application);

[0086] S104, start the spectrometer, synchronization module, and laser galvanometer scanning in sequence to obtain position information and spectrum information; after the scanning, the position information and the corresponding spectrum information can be obtained respectively, and the two files are saved to complete one operation;

[0087] S105, efficiency surface spectrum and position information fusion:

[0088] S106, selecting 12 spectral lines with wavelengths of 399.87nm, 407.86nm, 416.4nm, 430.04nm, 439.51nm, 450.13nm, 461.7nm, 474.2nm, 489.93nm, 502.51nm, 512.09nm, and 522.66nm at intervals along the wavelength as target spectral line λ n (n = 1, 2, 3 ... 12), the obtained x-axis and y-axis values ​​reflecting the position information and the target intensity of the target spectrum line are matched one by one to obtain 12 position intensity distribution diagrams, and the distribution diagrams are fitted on a fixed grid to obtain the intensity distribution I n (λ n ,x,y)(n=1,2,3…12), such as Figure 2 As shown;

[0089] S107, repeat the above steps 10 times to obtain 10 groups of spectral position information, and take the average of the nth (n=1, 2, 3...12) in each group, and we have Finally The maximum value is taken as the denominator for normalization and the efficiency distribution E is obtained by two-dimensional Gaussian fitting. n (λ n ,x,y)(n=1,2,3…12);

[0090] S108, select the spectral line λ of the element to be analyzed i =425.46nm, according to E n (λ n ,x,y)(n=1,2,3…12) where the parameters ω1, ω2, x c ,y c and λ n (n=1,2,3…12) The relationship fitting results in ω1, ω2, x c ,y c The relationship between and λ is as follows: Figures 3 - 6 As shown in the figure, we can get λ i The parameters ω1=5.70mm、ω2=7.34mm、x c =-1.15mm, y c =2.44 mm, thus obtaining E(λ i ,x,y) surface;

[0091] S109, Preparation for spectral acquisition of the sample to be measured (applied to scanning area 1): Define scanning area 1 as shown in Figure 7 Figure. The range of scanning area 1 is x: -8 to 8 mm, y: -4 to 4 mm, and the scanning path length is 16 mm. Place the sample to be measured in this area and adjust the scanning area to the sample plane. It should be noted that Figure 7 the efficiency surface area (i.e., the area formed by the largest border) in

[0092] is the acquisition area of this application. In the spectral acquisition of the sample to be measured in the embodiment of this application, the sample to be measured can be placed in scanning area 1 to perform spectral acquisition on the sample to be measured.

[0093] S110, Acquisition of the spectrum and position of the sample to be measured: Turn on the spectrometer, galvanometer scanner, and synchronization module in sequence to obtain the spectral information and position information of the sample to be measured;

[0093] S111, Fusion of the spectrum and position of the sample to be measured to obtain According to the obtained E(λ i , x, y), calculate the corrected spectral correction intensity where is the set of measurement intensities of the spectral line to be measured at each position point, is the set of corrected intensities of the spectral line to be measured at each position point.

[0094] In another way of spectral acquisition of the sample to be measured (applied to scanning area 2): At this time, the sample to be measured can be placed in scanning area 2 for spectral acquisition. Since the scanning range of the galvanometer of the acquisition system can be set, for example, when the sample to be measured is placed in scanning area 2, the scanning range of the galvanometer can correspond to scanning area 2 at this time. Similarly, when the sample to be measured is placed at other positions in the efficiency surface area, the scanning range of the galvanometer can be adjusted to the corresponding position accordingly. Therefore, in the embodiment of this application, the sample to be measured is placed in scanning area 1 and scanning area 2 to cope with the changes brought by the placement position of the sample to be measured. Thus, no matter which position the sample to be measured moves to within the acquisition area, the scanning range of the galvanometer can be adjusted to the corresponding position to obtain the acquisition efficiency at the corresponding position, so as to obtain the corrected intensity of the spectral line to be measured.

[0095] In the implementation manner for scanning area 2, the corrected intensity is obtained through the following steps:

[0096] S201, Select pure titanium as the standard sample for obtaining the efficiency surface.

[0097] S202, Select a high-repetition-rate pulsed fiber laser for the laser. Some of its parameters are: pulse width 123 ns, pulse repetition frequency 30 kHz, and laser power 30.2 W. Select the 403.08 nm spectral line of the Cr element as the spectral line to be analyzed.

[0098] S203, Set the galvanometer scanning parameters, laser parameters, spectrometer acquisition parameters, and synchronization module parameters. Among them, the scanning area range is -18.5 to 18.5 mm in the x direction and -18.5 to 18.5 mm in the y direction. As shown in the area, the scanning path length is 37 mm, and the scanning direction is one-way scanning. Place the pure titanium sample in the efficiency surface area (i.e., the acquisition area described in this application); Figure 7 As shown in the area, the scanning path length is 37 mm, and the scanning direction is one-way scanning. Place the pure titanium sample in the efficiency surface area (i.e., the acquisition area described in this application);

[0099] S204, Turn on the spectrometer, synchronization module, and laser galvanometer scanning in sequence to obtain position information and spectral information. After the scanning is completed, the position information and the corresponding spectral information can be obtained respectively, and these two files are saved to complete one operation;

[0100] S205, Fusion of efficiency surface spectrum and position information:

[0101] S206, Select 12 spectral lines with wavelengths of 399.87 nm, 407.86 nm, 416.4 nm, 430.04 nm, 439.51 nm, 450.13 nm, 461.7 nm, 474.2 nm, 489.93 nm, 502.51 nm, 512.09 nm, and 522.66 nm as the target spectral lines λ n (n = 1, 2, 3…12) at intervals along the wavelength. The x and y axis values reflecting the position information obtained are corresponding to the target intensities of the target spectral lines one by one to obtain 12 position intensity distribution maps, and the intensity distribution I n (λ n , x, y)(n = 1, 2, 3…12) is fitted on a fixed grid as shown; Figure 2 As shown;

[0102] S207, Repeat the above steps 10 times to obtain 10 groups of spectral position information, take the average of the nth (n = 1, 2, 3…12) in each group, and finally take the maximum value in Finally, take the maximum value in as the denominator for normalization and use two-dimensional Gaussian fitting to obtain the efficiency distribution E n (λ n , x, y)(n = 1, 2, 3…12);

[0103] S208, Select the spectral line of the element to be analyzed λ i = 425.46 nm. According to the parameters ω1, ω2, xc, yc and λ in E n (λ n , x, y)(n = 1, 2, 3…12) n(n = 1, 2, 3…12) The relationship between ω1, ω2, xc, yc, and λ is obtained by fitting, as Figures 3 - 6 shown, and then λ is obtained. i In i , the parameters are ω1 = 5.70 mm, ω2 = 7.34 mm, xc = -1.15 mm, yc = 2.44 mm, thus obtaining the E(λ i , x, y) surface;

[0104] S209. By setting the galvanometer scanning parameters, laser parameters, spectrometer acquisition parameters, and synchronization module parameters, where the range of the scanning area 2 is x: -8 to 8 mm, y: -14 to -6 mm, and the scanning path length is 16 mm, as Figure 7 shown for the scanning area 2.

[0105] S210. At this time, the spectral line λ i = 403.08 nm of the element to be analyzed is selected. According to E n (λ n , x, y) (n = 1, 2, 3…12), the relationship between ω1, ω2, x c , y c and λ n (n = 1, 2, 3…12) is obtained by fitting, as c shown, and then λ c is obtained. As Figures 3 - 6 shown, and then λ i is obtained. As Figures 3 - 6 shown, and then λ i is obtained. In i , the parameters are ω1 = 6.20 mm, ω2 = 8.08 mm, x c = -0.22 mm, y c = 3.43 mm, thus obtaining the E(λ i , x, y) surface, that is, the target efficiency surface of the spectral line λ i = 403.08 nm described in this application.

[0106] S211. The spectrum and position of the sample to be measured are fused to obtain According to the obtained E(λ i , x, y), the corrected spectral correction intensity is calculated where is the set of measured intensities of the spectral line to be measured at each position point, is the set of corrected intensities of the spectral line to be measured at each position point.

[0107] In summary, this application uses the method of the efficiency surface to make up for the disadvantage of large fluctuations in the spectral acquisition efficiency of the galvanometer FL-LIBS method, improves the deficiency of untrue spectral intensity caused by objective factors of the system, can obtain a more real spectrum, and is conducive to qualitative or quantitative analysis.

[0108] This application operates without changing the spectral system and can achieve industrial on-line and remote analysis. It retains the advantages of LIBS technology in aspects such as remote detection, on-line detection, and rapid analysis.

[0109] In addition, the above-mentioned drawings are only schematic illustrations of the processes included in the method according to the exemplary embodiments of the present application, rather than for limiting purposes. It is easy to understand that the processes shown in the above-mentioned drawings do not indicate or limit the chronological order of these processes. Additionally, it is also easy to understand that these processes can be executed, for example, synchronously or asynchronously in multiple modules.

[0110] It should be understood that the present application is not limited to the exact structures that have been described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A method for reducing the fluctuation of the spectral acquisition efficiency of a galvanometer FL-LIBS system, characterized in that, Applied to a collection system, the collection system is used to scan a sample to be measured or a standard sample within a collection area, and the method includes: Obtain efficiency surface information obtained by the collection system through scanning and collecting the standard sample. The efficiency surface information includes efficiency surfaces of multiple target spectral lines, and each efficiency surface is used to characterize the collection efficiency corresponding to each position point within the collection area of the collection system; For each target spectral line, determine the mapping relationship between the wavelength and the surface parameters according to the wavelength of the target spectral line and the surface parameters of the efficiency surface corresponding to the target spectral line; Obtain target spectral information obtained by the collection system through scanning and collecting the sample to be measured. The target spectral information includes spectral information collected by the collection system at each of the position points, and each spectral information includes multiple spectral lines to be measured and the measurement intensities of each of the spectral lines to be measured; For each spectral line to be measured, determine the target surface parameters of the spectral line to be measured according to the wavelength of the spectral line to be measured and the mapping relationship, and determine the target efficiency surface of the spectral line to be measured based on the target surface parameters, and determine the corrected intensity of the spectral line to be measured according to the measurement intensity of the spectral line to be measured at the selected position point and the target efficiency surface, so as to perform quantitative analysis on the sample to be measured according to the corrected intensities of each of the spectral lines to be measured.

2. The method according to claim 1, wherein The obtaining the efficiency surface information obtained by the collection system through scanning and collecting the standard sample includes: Perform scanning on the standard sample for a target number of rounds to obtain multiple groups of scanning information corresponding to the target number. Each group of scanning information includes standard spectral information corresponding one-to-one to each of the position points, and each standard spectral information includes intensity position distribution information of each of the target spectral lines; For each position point, take the average of the intensity position distribution information of each target spectral line in each group of scanning information according to the target number to obtain the target intensity of each target spectral line; For each target spectral line, select the position point with the maximum target intensity among the target intensities corresponding to each position point as the target position point, mark the collection efficiency of the target position point as one, and perform normalization processing on each position point according to the target intensities of each position point to obtain the collection efficiency of each position point, and determine the efficiency surface of the target spectral line according to each collection efficiency; Determine the efficiency surface information according to the efficiency surfaces of each target spectral line.

3. The method according to claim 2, wherein The surface parameters of the efficiency surface include a first surface parameter, a second surface parameter, a third surface parameter, and a fourth surface parameter. The determining the mapping relationship between the wavelength and the surface parameters according to the wavelength of the target spectral line and the surface parameters of the efficiency surface corresponding to the target spectral line includes: Input the wavelength of the target spectral line into a preset fitting calculation formula to obtain the first surface parameter, the second surface parameter, the third surface parameter, and the fourth surface parameter of the efficiency surface corresponding to the target spectral line, so as to determine the mapping relationship between the wavelength and the surface parameters; Among them, the fitting calculation formula is applicable to each of the target spectral lines or each of the spectral lines to be measured.

4. The method according to claim 3, characterized in that, The determining the target surface parameters of the spectral line to be measured according to the wavelength of the spectral line to be measured and the mapping relationship includes: According to the mapping relationship, input the wavelength of the spectral line to be measured into the fitting calculation formula to obtain the target surface parameters of the spectral line to be measured; Among them, the target surface parameters include a first target surface parameter, a second target surface parameter, a third target surface parameter, and a fourth target surface parameter.

5. The method according to claim 4, characterized in that The determining the target efficiency surface of the spectral line to be measured based on the target surface parameters includes: Determine the target efficiency surface of the spectral line to be measured according to the first target surface parameter, the second target surface parameter, the third target surface parameter, and the fourth target surface parameter, so as to determine the acquisition efficiency of each position point according to the target efficiency surface.

6. The method according to claim 5, wherein The determining the corrected intensity of the spectral line to be measured according to the measured intensity of the spectral line to be measured at the selected position point and the target efficiency surface includes: Obtain the target acquisition efficiency corresponding to the selected position point according to the target efficiency surface; Divide the measured intensity by the target acquisition efficiency to obtain the corrected intensity of the spectral line to be measured.

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