A method to reduce the fluctuation of spectral acquisition efficiency of galvanometer FL-LIBS system

Abstract

The present application relates to the technical field of spectral analysis, and relates to a method for reducing fluctuations in the spectrum acquisition efficiency of a galvanometer FL‑LIBS system. The method comprises: obtaining efficiency surface information; for each target spectrum line, determining a mapping relationship between wavelength and surface parameters according to the wavelength of the target spectrum line and the surface parameters; obtaining target spectrum information; for each spectrum line to be measured, determining target surface parameters according to the wavelength of the spectrum line to be measured and the mapping relationship, and determining a target efficiency surface based on the target surface parameters and each position point, and determining a correction intensity of the spectrum line to be measured according to the measured intensity of the spectrum line to be measured at the selected position point and the target efficiency surface, so as to facilitate quantitative analysis of the sample to be measured according to the correction intensity of each spectrum line to be measured. The method of the present application can overcome the problem of unrealistic spectral intensity caused by fluctuations in the acquisition efficiency of the acquisition system due to factors such as dispersion, and solves the problems and pain points of weak spectral stability and low analysis accuracy in the prior art.

Description

Technical Field

[0001] The present application relates to the field of spectral analysis technology, and in particular, to a method for reducing fluctuations in 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 the laser onto the surface of the sample to be analyzed to generate plasma, and then obtain the type and content information of the elements inside the sample by collecting and analyzing the spectrum generated by the plasma. LIBS technology has the advantages of full element, nearly non-destructive, in-situ, fast, and capable of detecting solid, liquid, and gas, and is therefore widely used for element detection in various fields. The LIBS technology that uses 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] Incorporating galvanometers into FL-LIBS systems offers unique advantages for acquiring spectra from large, heavy samples. Furthermore, their extremely fast scanning speeds enable ultra-high-speed spectral acquisition. However, galvanometers require a field lens, which can cause fluctuations in the system's spectral acquisition efficiency. Specifically, factors such as optical system dispersion can cause significant differences in spectra collected from different locations on the surface of a sample with the same elemental distribution. The fundamental principle of LIBS is that spectral intensity reflects elemental content. Spectra obtained from galvanometer-based FL-LIBS systems fail to accurately reflect elemental distribution, hindering final qualitative or quantitative elemental analysis.

[0004] To address these shortcomings, a method is urgently needed to improve them. Because factors such as optical system dispersion are objective and unavoidable, a method is needed to reduce fluctuations in the galvanometer FL-LIBS spectral acquisition efficiency. This would improve the stability of the spectra collected by the galvanometer FL-LIBS system, enabling the collected spectra to accurately reflect the two-dimensional surface distribution of elements and enhance the accuracy of galvanometer FL-LIBS analysis. Summary of the Invention

[0005] The present application provides a method for reducing fluctuations in 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 provide a beneficial option or create conditions.

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

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

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

[0009] For each target spectral line, determining a 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] Obtaining target spectral information obtained by the acquisition system through scanning and acquisition of the sample to be tested, wherein the target spectral information includes spectral information collected by the acquisition system at each of the position points, and each of the spectral information includes multiple spectral lines to be tested and the measured intensity of each of the spectral lines to be tested;

[0011] For each of the spectral lines to be measured, the target surface parameters of the spectral line to be measured are determined according to the wavelength of the spectral line to be measured and the mapping relationship, and the target efficiency surface of the spectral line to be measured is determined based on the target surface parameters, and the correction intensity of the spectral line to be measured is determined according to the measured intensity of the spectral line to be measured at the selected position point and the target efficiency surface, so as to facilitate quantitative analysis of the sample to be measured according to the correction intensity of each spectral line to be measured.

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

[0013] Scanning the standard sample a target number of times to obtain multiple sets of scanning information corresponding to the target number, each set of scanning information including standard spectrum information corresponding to each of the position points, each set of standard spectrum information including intensity position distribution information of each of the target spectral lines;

[0014] For each of the position points, averaging the intensity position distribution information of each target spectral line of each group of the scanning information according to the number of targets, to obtain the target intensity of each target spectral line;

[0015] For each target spectral line, a position point with the largest target intensity is selected from the target intensities corresponding to the position points as the target position point, and the acquisition efficiency of the target position point is marked as one. Each position point is normalized according to the target intensity of each position point to obtain the acquisition efficiency of each position point, and the efficiency surface of the target spectral line is determined according to each acquisition efficiency;

[0016] The efficiency surface information is determined according to the efficiency surfaces of the target spectral lines.

[0017] In one embodiment of the present application, based on the aforementioned 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. Determining a 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] Inputting the wavelength of the target spectral line into a preset fitting calculation formula to obtain a first surface parameter, a second surface parameter, a third surface parameter, and a fourth surface parameter of the efficiency surface corresponding to the target spectral line, so as to determine a mapping relationship between the wavelength and the surface parameters;

[0019] The fitting calculation formula is applicable to each target spectral line or each spectral line to be measured.

[0020] In one embodiment of the present application, based on the above solution, determining the target surface parameter of the spectral line to be measured according to the wavelength of the spectral line to be measured and the mapping relationship includes:

[0021] According to the mapping relationship, the wavelength of the spectral line to be measured is input into the fitting calculation formula to obtain the target surface parameter of the spectral line to be measured;

[0022] 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 one embodiment of the present application, based on the above solution, determining the target efficiency surface of the spectral line to be measured based on the target surface parameters includes:

[0024] The target efficiency surface of the spectrum line to be measured is determined 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 collection efficiency of each of the position points according to the target efficiency surface.

[0025] In one embodiment of the present application, based on the above solution, determining the correction 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:

[0026] Acquire the target collection efficiency corresponding to the selected position point according to the target efficiency surface;

[0027] The measured intensity is divided by the target acquisition efficiency to obtain the corrected intensity of the spectral line to be measured.

[0028] The principle of this application is: the acquisition system, that is, the galvanometer FL-LIBS system mentioned in the background technology, collects the efficiency surface information of the standard sample in the acquisition area through the 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, we can obtain the spectral line intensity at different locations for each spectral line, and from this, we can infer the acquisition efficiency of the acquisition system at each location within the acquisition area. The acquisition efficiency is also related to the wavelength of the spectral line. Since a mapping relationship between wavelength and surface parameters has been established using the efficiency surface, the target surface parameters for the spectral line to be measured can be obtained simply by comparing the wavelength of the spectral line to this mapping relationship. Using the target surface parameters, we can generate a target efficiency surface, which represents the acquisition efficiency of the spectral line to be measured at each location.

[0030] During the actual acquisition process, the system collects spectral information at selected locations. This spectral information provides the measured intensity of each spectral line at that location. Furthermore, the corrected intensity of each spectral line can be determined by comparing the measured intensity with the target efficiency curve for the spectral line. Once the corrected intensity for each spectral line is calculated, quantitative analysis of the sample can be performed.

[0031] The beneficial effects of the present application are as follows: by determining the acquisition efficiency of different position points, the correction intensity of each spectral line to be measured in the spectral information corresponding to the position point can be known, so as to perform quantitative analysis on the sample to be measured and improve the accuracy of quantitative analysis. It can overcome the problem of unrealistic spectral intensity caused by fluctuations in the acquisition efficiency due to factors such as dispersion in the acquisition system, and solve the problems and pain points of weak spectral stability and low analysis accuracy in the prior art.

[0032] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings are incorporated into and constitute a part of the specification, illustrating embodiments consistent with the present application and, together with the specification, explaining the principles of the present application. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0034] Figure 1 This is a flow chart of a method for reducing fluctuations in spectral acquisition efficiency of a galvanometer FL-LIBS system according to an embodiment of the present application;

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

[0036] Figure 3 1 is a fitting relationship diagram between wavelength and parameter ω1 according to an embodiment of the present application;

[0037] Figure 4 2 is a fitting relationship diagram between wavelength and parameter ω2 according to an embodiment of the present application;

[0038] Figure 5 The wavelength and parameter x shown in the embodiment of the present application c The fitting relationship diagram of

[0039] Figure 6 The wavelength and parameter y shown in the embodiment of the present application c The fitting relationship diagram of

[0040] Figure 7 Schematic diagram of a plane 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, example embodiments can be implemented in many 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 thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art.

[0042] In addition, described feature, structure or characteristic can be combined in one or more embodiments in any suitable manner.In the following description, many specific details are provided so as to provide a full understanding of the embodiments of the present application. However, it will be appreciated by those skilled in the art that the technical scheme of the present application can be put into practice without one or more of the specific details, or other methods, components, devices, steps etc. can be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid blurring the various aspects of the application.

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

[0044] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0045] It should be noted that the term "plurality" used in this document refers to two or more. "And / or" describes a relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. The character " / " generally indicates an "or" relationship between the associated objects.

[0046] The following is a detailed introduction to the logical principles of this application:

[0047] First, the acquisition system mentioned in this application is the galvanometer FL-LIBS system mentioned in the background technology. The acquisition system can be moved to a certain position within the acquisition area to collect spectra. The acquired spectral information contains multiple spectral lines and the measured intensity of each spectral line. However, due to factors such as dispersion in the optical system mentioned in the background technology, the measured intensity of the spectral line is not the true intensity. At this time, this application introduces acquisition efficiency to reflect the connection between measured intensity and true intensity.

[0048] At the same time, the acquisition system has different collection efficiencies at different locations. For example, during the spectral information acquisition process of a standard sample (i.e., a pure sample without interference from other elements), the measured intensities of a spectral line at positions A and B are 800 and 1000, respectively. Therefore, the collection efficiency varies at different locations within the acquisition area. It should be noted that, taking pure titanium as an example, the standard sample has no interference from other elements, so the collection efficiency at different locations will not be affected by interference from other elements (spectral lines). This establishes a correlation between different locations and collection efficiency.

[0049] By performing a spectrum acquisition on each acquisition point (i.e., each position point) in the acquisition area, the measured intensity of each spectrum line (this application only selects a part of the spectrum lines as the target spectrum lines for analysis) can be obtained. Taking a certain target spectrum line as an example, this application takes the position point with the largest measured intensity (i.e., the target intensity of the target spectrum line described in this application) as the target position point. At this time, the acquisition efficiency is the highest, that is, the target intensity of each position point is normalized according to the acquisition efficiency of the target position point as 1, and the acquisition efficiency of each position point is obtained by proportional conversion to generate an efficiency surface (the efficiency surface actually characterizes the acquisition efficiency corresponding to each position point). It should be noted that the efficiency surface of each target spectrum line is different. For example, the acquisition efficiency of target spectrum line a at position point A is 0.9, and the acquisition efficiency at position point B is 0.8; however, the acquisition efficiency of target spectrum line b at position point A is 0.85, and the acquisition efficiency at position point B is 0.7. In this way, according to different target spectrum lines (i.e., the target spectrum line is identified according to the wavelength of the target spectrum line), the corresponding efficiency surface is generated.

[0050] In the actual spectrum acquisition of the sample to be tested, since different spectral lines to be tested are distinguished by their wavelengths, for example, the wavelength of the spectral line c is 430.04nm, and the wavelength of the spectral line d is 450.13nm, we only need to know the wavelength of the spectral line to know the information of the spectral line. The collected target spectrum information of the sample to be tested also contains the spectral information of each position point, that is, the measured intensity of each spectral line to be tested at the corresponding position point can be determined from the spectral information (the measured intensity at this time is also inaccurate and needs to be calculated based on the acquisition efficiency to obtain the corrected intensity).

[0051] The acquisition efficiency can then be determined by the wavelength of the spectral line to be measured, because the mapping relationship between wavelength and surface parameters can be obtained from the analysis of standard samples. This mapping relationship can be reflected by a fitting calculation formula, which can be applied to efficiency surfaces or target efficiency surfaces. Through this fitting calculation formula, the acquisition efficiency of the spectral line to be measured at a certain position can be obtained. In turn, the acquisition efficiency of each spectral line to be measured can be obtained. The acquisition system performs spectral acquisition at a selected position point. Simply divide 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 to obtain the corrected intensity of the spectral line to be measured. After the corrected intensity of each spectral line to be measured is calculated, quantitative analysis of the sample to be measured can be performed.

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

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

[0054] First, it's important to note that the wavelength of the target spectral line is known. The efficiency surface provides information about the acquisition efficiency at each location. Preparing for acquiring the efficiency surface involves setting the galvanometer scanning parameters, laser parameters, spectrometer acquisition parameters, and synchronization module parameters. Opening the serial port, placing a pure sample within the scanning plane, and leveling the sample surface are also essential.

[0055] Spectrum and position acquisition: Turn on the spectrometer, synchronization module, and laser galvanometer scanning in sequence to obtain position information and spectrum information, where the position information and spectrum information constitute the scanning information in this application.

[0056] Fusion of efficiency surface spectrum and position information: N spectral lines (corresponding to N efficiency surfaces, N is exemplarily 12 in this application) are selected as target spectral lines λ at each wavelength interval n (n = 1, 2, 3 ... N), the obtained x, y coordinates reflecting the position information (corresponding to the position point in this application) and the target intensity of the target spectrum line are matched one by one to obtain N position intensity distribution maps (i.e., the efficiency surface in this application), and the position intensity distribution map is interpolated on a fixed grid to obtain the intensity distribution I n (λ n,x,y)(n=1,2,3…N). The intensity position distribution information graph (ie, the efficiency surface of this application) can be as follows Figure 2 As shown in the figure, Efficiency represents the collection efficiency.

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

[0058] Scanning the standard sample a target number of times to obtain multiple sets of scanning information corresponding to the target number, each set of scanning information including standard spectrum information corresponding to each of the position points, each set of standard spectrum information including intensity position distribution information of each of the target spectral lines;

[0059] For each of the position points, averaging the intensity position distribution information of each target spectral line of each group of the scanning information according to the number of targets, to obtain the target intensity of each target spectral line;

[0060] For each target spectral line, a position point with the largest target intensity is selected from the target intensities corresponding to the position points as the target position point, and the acquisition efficiency of the target position point is marked as one. Each position point is normalized according to the target intensity of each position point to obtain the acquisition efficiency of each position point, and the efficiency surface of the target spectral line is determined according to each acquisition efficiency;

[0061] The efficiency surface information is determined according to the efficiency surfaces of the target spectral lines.

[0062] Specifically, to avoid contingency, the standard sample is scanned repeatedly k times to obtain k groups of scanning information (including position information and spectral information), and the nth (n = 1, 2, 3 ... N) spectral line in each group of scanning information is averaged. That is to say, the target spectrum line corresponding to each position point has collected the spectrum line intensity k times, and the k spectrum line intensities obtained by the k collections need to be averaged to represent the target intensity of the target spectrum line to be measured at the position point. Take the maximum value as the denominator and normalize to get the efficiency distribution E n (λ n ,x,y)(n=1,2,3…N), it should be noted that the maximum value is taken, that is, the target intensity of the spectrum line to be measured at each position point for comparison, and the position point with the largest intensity is selected as the target position point, and the acquisition efficiency of the position point at this time is marked as one, and then normalization is performed to obtain the efficiency distribution of each position point, so from E n (λ n,x,y)(n=1,2,3…N), we can know the acquisition efficiency corresponding to any target spectrum line at any position point.

[0063] In step S2, for each target spectral line, a mapping relationship between wavelength and 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 a 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 a first surface parameter, a second surface parameter, a third surface parameter, and a fourth surface parameter of the efficiency surface corresponding to the target spectral line, so as to determine a mapping relationship between the wavelength and the surface parameters;

[0066] The fitting calculation formula is applicable to each target spectral line or each spectral line to be measured.

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

[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 represent the first surface parameter (i.e., the half-height width in the x direction) and the second surface parameter (i.e., the half-height width in the y direction), respectively, and x c and y c Represent the third and fourth surface parameters respectively, that is, x c and y c It should be noted that the relationship between ω1, ω2 and wavelength is obtained by quadratic fitting, x c and y c Through linear fitting, the fitting relationship between the four parameters and wavelength can be obtained as follows: Figure 3-Figure 6 As shown, in Figure 3-Figure 6 Where Wavelength represents wavelength. The fitting calculation formula is applicable to each target spectrum line or each spectrum line to be measured, ω1, ω2, x c and y c Also represent the first target surface parameter, the second target surface parameter, the third target surface parameter and the fourth target surface parameter. In general, through the wavelength of the spectrum to be measured and the mapping relationship (see Figure 3-6) can obtain the first target surface parameters, the second target surface parameters, the third target surface parameters and the fourth target surface parameters.

[0070] Furthermore, by inputting the first target surface parameters, the second target surface parameters, the third target surface parameters and the fourth target surface parameters into the fitting calculation formula, 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, thereby knowing the collection efficiency corresponding to each position point.

[0071] Furthermore, determining the target efficiency surface of the spectral line to be measured based on the target surface parameters includes:

[0072] The target efficiency surface of the spectrum line to be measured is determined 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 collection efficiency of each of the position points according to the target efficiency surface.

[0073] Specifically, for each of the position points, since the first target surface parameters, the second target surface parameters, the third target surface parameters, the fourth target surface parameters, and the wavelength of the spectrum line to be measured have been known through the above steps, it is only necessary to input the position point corresponding to the spectrum line to be measured into the fitting calculation formula to obtain the acquisition efficiency of the acquisition system at the position point.

[0074] The acquisition efficiency of each position point is obtained by calculation, so the target efficiency surface can be generated, and E(λ i ,x,y) expression, that is, from E(λ i ,x,y) can be used to know the collection efficiency of any spectral line to be measured at any position.

[0075] In step S3, the target spectral information obtained by the acquisition system through scanning and acquisition of the sample to be tested is obtained, and the target spectral information includes the spectral information collected by the acquisition system at each of the position points, and each of the spectral information includes multiple spectral lines to be tested and the measurement intensity of each of the spectral lines to be tested.

[0076] Specifically, in the actual spectrum acquisition of the sample to be tested, since different spectral lines to be tested are distinguished by their wavelengths, for example, the wavelength of the spectral line c to be tested is 430.04nm, and the wavelength of the spectral line to be tested is 450.13nm, then we only need to know the wavelength of the spectral line to know the information of the spectral line. The target spectrum information of the sample to be tested also contains the spectral information of each position point, that is, the measured intensity of each spectral line to be tested at the corresponding position point can be determined from the spectral information (the measured intensity at this time is also inaccurate and needs to be calculated based on the acquisition efficiency to obtain the corrected intensity).

[0077] In step S4, for each of the spectral lines to be measured, the target surface parameters of the spectral line to be measured are determined according to the wavelength of the spectral line to be measured and the mapping relationship, and the target efficiency surface of the spectral line to be measured is determined based on the target surface parameters, and the correction intensity of the spectral line to be measured is determined according to the measured intensity of the spectral line to be measured at the selected position point and the target efficiency surface, so as to facilitate quantitative analysis of the sample to be measured according to the correction intensity of each spectral line to be measured.

[0078] In one embodiment of the present application, determining the correction intensity of the spectral line to be measured based on the measured intensity of the spectral line to be measured at the selected position point and the target efficiency surface includes:

[0079] Acquire the target collection efficiency corresponding to the selected position point according to the target efficiency surface;

[0080] The measured intensity is divided by the target acquisition efficiency to obtain the corrected intensity of the spectral line to be measured.

[0081] Specifically, from E(λ i ,x,y) can be used to determine the target acquisition efficiency of any spectral line to be measured at any location. The wavelength of the spectral line to be measured can be used to determine the measured intensity corresponding to the spectral line at the selected location. Dividing the measured intensity by the target acquisition efficiency yields the corrected intensity of the spectral line to be measured. Once the corrected intensity of each spectral line has been calculated, quantitative analysis of the sample can be performed based on theoretical knowledge of spectroscopy.

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

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

[0084] S102 : A high repetition rate pulsed fiber laser is selected as the laser. Some of its parameters are: pulse width 123 ns, pulse repetition frequency 30 kHz, and laser power 30.2 W. The 425.46 nm spectral line of the Cr element is selected 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 x-direction: -18.5~18.5mm, y-direction: -18.5~18.5mm, such as Figure 7 In the area shown, the scanning path length is 37 mm, the scanning direction is unidirectional scanning, and the pure titanium sample is placed in the efficiency surface area (i.e., the collection area described in this application);

[0086] S104, sequentially start the spectrometer, synchronization module, and laser galvanometer scanning to obtain position information and spectral information; after the scanning is completed, the position information and corresponding spectral information can be obtained respectively, and these two files are saved, completing one operation;

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

[0088] S106: 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 at intervals along the wavelength as target spectral lines 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 maps, and the distribution maps 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 Take the maximum value 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);

[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) relationship fitting yields ω1, ω2, x c 、y c The relationship between and λ is as follows: Figure 3-6 As shown, we can get λ i The parameters ω1=5.70mm、ω2=7.34mm、x c =-1.15mm, y c =2.44mm, thus obtaining E(λ i ,x,y) surface;

[0091] S109, preparation for spectrum acquisition of sample to be tested (applied to scanning area 1): demarcate as follows Figure 7 The scanning area 1 shown in the figure has a range of x: -8~8mm, y: -4~4mm, and a scanning path length of 16mm. The sample to be tested is placed in this area and the scanning area is adjusted to the sample plane. It should be noted that Figure 7 The efficiency surface area (ie, the area formed by the largest frame) is the acquisition area of ​​the present application. In the spectrum acquisition of the sample to be tested in the embodiment of the present application, the sample to be tested can be placed in the scanning area 1 to acquire the spectrum of the sample to be tested.

[0092] S110, spectrum and position acquisition of the sample to be tested: sequentially start the spectrometer, galvanometer scanning, and synchronization module to obtain spectrum information and position information of the sample to be tested;

[0093] S111, spectrum and position of the sample to be tested are fused to obtain According to the obtained E(λ i ,x,y) calculate the spectral correction intensity after correction in 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 measured spectral line at each position point.

[0094] In another way of collecting the spectrum of the sample to be tested (applied to scanning area 2): the sample to be tested can be placed in scanning area 2 for spectrum collection, because the scanning range of the galvanometer of the collection system can be set. For example, if the sample to be tested is placed in scanning area 2, the scanning range of the galvanometer can correspond to scanning area 2. Similarly, if the sample to be tested is placed in other positions in the efficiency surface area, the scanning range of the galvanometer can be adjusted to the corresponding position accordingly. Therefore, the embodiment of the present application places the sample to be tested in scanning area 1 and scanning area 2 in order to cope with the changes brought about by the placement position of the sample to be tested. Therefore, no matter where the sample to be tested moves to in the collection area, the scanning range of the galvanometer can be adjusted to the corresponding position to obtain the collection efficiency of the corresponding position, so as to obtain the corrected intensity of the spectral line to be tested.

[0095] In the embodiment for scanning area 2, the calibration intensity is obtained by the following steps:

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

[0097] S202 : A high repetition rate pulsed fiber laser is selected as the laser, with the following parameters: pulse width 123 ns, pulse repetition frequency 30 kHz, and laser power 30.2 W. The 403.08 nm spectral line of the Cr element is selected as the spectral line to be analyzed.

[0098] S203, set the galvanometer scanning parameters, laser parameters, spectrometer acquisition parameters, synchronization module parameters, where the scanning area range is x direction: -18.5 ~ 18.5mm, y direction: -18.5 ~ 18.5mm, such as Figure 7 In the area shown, the scanning path length is 37 mm, the scanning direction is unidirectional scanning, and the pure titanium sample is placed in the efficiency surface area (i.e., the collection area described in this application);

[0099] S204, sequentially start the spectrometer, synchronization module, and laser galvanometer scanning to obtain position information and spectral information; after the scanning is completed, the position information and corresponding spectral information can be obtained respectively, and these two files are saved, completing one operation;

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

[0101] S206, 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 lines 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 maps, and the distribution maps 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;

[0102] S207, 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 Take the maximum value 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 λ of the element to be analyzed i =425.46nm, according to E n (λ n ,x,y)(n=1,2,3…12) in which the parameters ω1, ω2, xc, yc and λ n(n=1,2,3…12) The relationship between ω1, ω2, xc, yc and λ is obtained by fitting the relationship, such as Figure 3-6 As shown, we can get λ i The parameters ω1=5.70mm、ω2=7.34mm、xc=-1.15mm、yc=2.44mm, thus we get E(λ i ,x,y) surface;

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

[0105] S210, at this time, select the spectral line λ of the element to be analyzed i =403.08nm, 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) relationship fitting yields ω1, ω2, x c 、y c The relationship between and λ is as follows: Figure 3-6 As shown, we can get λ i ,like Figure 3-6 As shown, we can get λ i The parameters ω1=6.20mm、ω2=8.08mm、x c =-0.22mm, y c =3.43mm, thus obtaining E(λ i ,x,y) surface, that is, the spectrum line λ described in this application i =Target efficiency surface of 403.08nm.

[0106] S211, spectrum and position of the sample to be tested are fused to obtain According to the obtained E(λ i ,x,y) calculate the spectral correction intensity after correction in 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 measured spectral line at each position point.

[0107] In summary, the efficiency surface method used in this application can make up for the shortcomings of the galvanometer FL-LIBS method with large fluctuations in spectral acquisition efficiency, improve the deficiency of unrealistic spectral intensity caused by objective system factors, and obtain more realistic spectra, which is conducive to qualitative or quantitative analysis.

[0108] This application operates without changing the spectral system, enabling industrial online and remote analysis, while retaining the advantages of LIBS technology in remote detection, online testing, and rapid analysis.

[0109] Furthermore, the above-mentioned figures are merely illustrative of the processes included in the methods according to exemplary embodiments of the present application and are not intended to be limiting. It is readily understood that the processes illustrated in the above-mentioned figures do not indicate or limit the temporal order of these processes. Furthermore, it is readily understood that these processes may be executed synchronously or asynchronously, for example, 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 that various modifications and changes can be performed without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for reducing fluctuations in spectral acquisition efficiency of a galvanometer FL-LIBS system, characterized in that: Applied to a collection system for scanning a sample to be tested or a standard sample within a collection area, the method comprises: Acquiring efficiency surface information obtained by scanning and collecting the standard sample by the acquisition system, wherein the efficiency surface information includes efficiency surfaces of multiple target spectral lines, each of the efficiency surfaces being used to characterize the acquisition efficiency of the acquisition system corresponding to each position point in the acquisition area; For each target spectral line, determining a 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; Obtaining target spectral information obtained by the acquisition system through scanning and acquisition of the sample to be tested, wherein the target spectral information includes spectral information collected by the acquisition system at each of the position points, and each of the spectral information includes multiple spectral lines to be tested and the measured intensity of each of the spectral lines to be tested; For each of the spectral lines to be measured, a target surface parameter of the spectral line to be measured is determined according to the wavelength of the spectral line to be measured and the mapping relationship, and a target efficiency surface of the spectral line to be measured is determined based on the target surface parameter, and a correction intensity of the spectral line to be measured is determined according to the measured intensity of the spectral line to be measured at a selected position point and the target efficiency surface, so as to facilitate quantitative analysis of the sample to be measured according to the correction intensity of each spectral line to be measured; The obtaining of efficiency surface information obtained by scanning and collecting the standard sample by the collection system includes: Scanning the standard sample a target number of times to obtain multiple sets of scanning information corresponding to the target number, each set of scanning information including standard spectrum information corresponding to each of the position points, each set of standard spectrum information including intensity position distribution information of each of the target spectral lines; For each of the position points, averaging the intensity position distribution information of each target spectral line of each group of the scanning information according to the number of targets, to obtain the target intensity of each target spectral line; For each target spectral line, a position point with the largest target intensity is selected from the target intensities corresponding to the position points as the target position point, and the acquisition efficiency of the target position point is marked as one. Each position point is normalized according to the target intensity of each position point to obtain the acquisition efficiency of each position point, and the efficiency surface of the target spectral line is determined according to each acquisition efficiency; Determining the efficiency surface information according to the efficiency surfaces of each target spectral line; 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 a 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: Inputting the wavelength of the target spectral line into a preset fitting calculation formula to obtain a first surface parameter, a second surface parameter, a third surface parameter, and a fourth surface parameter of the efficiency surface corresponding to the target spectral line, so as to determine a mapping relationship between the wavelength and the surface parameters; The fitting calculation formula is applicable to each target spectral line or each spectral line to be measured.

2. The method according to claim 1, characterized in that The determining the target surface parameter 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, the wavelength of the spectral line to be measured is input into the fitting calculation formula to obtain the target surface parameter of the spectral line to be measured; 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.

3. The method according to claim 2, characterized in that The determining the target efficiency surface of the spectral line to be measured based on the target surface parameters includes: The target efficiency surface of the spectrum line to be measured is determined 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 collection efficiency of each of the position points according to the target efficiency surface.

4. The method according to claim 3, characterized in that The step of determining the correction 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: Acquire the target collection efficiency corresponding to the selected position point according to the target efficiency surface; The measured intensity is divided by the target acquisition efficiency to obtain the corrected intensity of the spectral line to be measured.

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