CN103411931A - Remote LIBS element quantitative analysis method based on weighted multispectral calibration - Google Patents

Abstract

The invention discloses a remote LIBS (Laser-induced Breakdown Spectroscopy) element quantitative analysis method based on weighted multispectral calibration. The method comprises the following steps: firstly, achieving remote target LIBS spectral acquisition of a test site, and in the process, qualitatively obtaining major element compositions of the remote target to be tested, as well as the line strengths of multiple spectral lines of elements to be tested; then, finishing laboratory sample calibration and obtaining the relation fitted equation between the strengths and the percentage contents of the multiple lines of the elements to be tested; finally, quantitatively calculating the percentage contents of the elements to the tested according to the multispectral weighting method. The method can solve the remote LIBS element quantitative analysis problems better.

Description

Long-range LIBS quantitative elementary analysis method based on the demarcation of weighting multiline

Technical field

This patent relates to a kind of laser spectrum quantitative elementary analysis method, relates in particular to a kind of remote laser induced breakdown spectroscopy of demarcating based on the weighting multiline (Laser-induced breakdown spectroscopy is called for short LIBS) quantitative analysis method.

Background technology

The occasion that can't approach some testers, as the chemical contamination zone; The zones with a varied topography such as crag, river valley, solution cavity, carrying out material chemistry element set one-tenth and content analysis is a difficult problem, carries out chemical analysis because the tester can't gather target sample.In this case, can utilize remote laser induced breakdown spectroscopy (LIBS) Detection Techniques to solve.

Remote laser induced breakdown spectroscopy (LIBS) Detection Techniques are to utilize high energy pulse laser, through condenser lens, focus on long-range target surface, on focus point, obtain the laser pulse of instantaneous high power density, can make the ablation of target surface focus point, evaporation and ionization form the plasma spark of high temperature, high pressure, high electron density, give off the spectrum that comprises atom and ion characteristic spectral line, the element that can be used for detecting material forms.

A major issue of long-range LIBS Detection Techniques is the content of accurate analysis target component how.Because the tester can't be near target, and the priori that does not have object element to form, make quantitative test become a difficult problem.

For solving long-range LIBS quantitative elementary analysis problem, this patent proposes a kind of long-range LIBS quantitative elementary analysis method of demarcating based on the weighting multiline.At first complete test site distant object LIBS spectra collection, line strength of the essential element of the remote target to be measured of qualitative acquisition composition and many spectral lines of element to be measured in this process; Second step completes the laboratory sample calibration, obtains the fit equation that concerns between many line strength of element to be measured and degree; Finally according to the multiline weighted method, quantitatively calculate the degree of element to be measured.

Summary of the invention

The purpose of this patent is to provide a kind of long-range LIBS quantitative elementary analysis method of demarcating based on the weighting multiline, solves long-range LIBS quantitative elementary analysis problem.

This patent is achieved like this, and its method step is:

Step 1, complete test site distant object LIBS spectra collection

In test site, set up long-range LIBS testing apparatus, the domain test personnel between long-range LIBS testing apparatus and distant object are unapproachable (for example chemical contamination zone, the dangerous geographical environment such as precipice etc.).The LIBS spectroscopic data that utilizes long-range LIBS testing apparatus to obtain distant object is measured the distance L of distant object simultaneously with the laser range finder carried on testing apparatus, in order to improve reliability and to eliminate disturbance, the several times LIBS spectroscopic data that laser pulse is induced averages, and obtains the average LIBS spectroscopic data of distant object.According to the average LIBS curve of spectrum, the essential element that obtains distant object forms and line strength corresponding to some spectral lines of element X to be measured.

Step 2, laboratory sample are demarcated

The essential element of the distant object obtained according to step 1 forms, selection contains the several compound of element X to be measured and target chief component element, and this several compound is prepared to several samples with different ratio row, with balance, measure the quality of each compound in sample, according to molecular formula, calculate respectively the degree of element X in each sample.

In laboratory, the mode the same with test site installs long-range LIBS testing apparatus, now the tester can place sample on the long-range LIBS testing apparatus L of distance position far away, repeatedly LIBS spectroscopic data to each sample collection averages, and obtains respectively line strength of some the spectral lines identical with step 1 of element X.

The line strength of take is ordinate, and the degree of element X is horizontal ordinate, carries out linear fit, obtains the fitting a straight line equation of some spectral lines of element X.

Step 3, multiline weighted method are quantitatively calculated the degree K of element X to be measured.

The fitting a straight line equation of these spectral lines that line strength that some the spectral lines of element X that obtain according to step 1 are corresponding and step 2 obtain, can obtain respectively the degree based on these spectral line gained of element X to be measured.

These degree of confidence based on the degree of the different spectral line gained of element X are directly proportional to the weight of line strength of these spectral lines, according to the weighted average calculation of these degrees, obtain the degree K of element X to be measured.

The method is under laboratory condition, in the distance identical with the on-the-spot test target, place the calibration sample of preparation, and utilized many spectral lines of element to be measured to demarcate, when finally calculating, the spectral intensity of every spectral line of foundation is as weight, utilize the weighting multiline to demarcate the degree that obtains element to be measured, can solve the difficult problem of long-range LIBS quantitative elementary analysis.

The accompanying drawing explanation

Fig. 1 is the schematic diagram of this patent, in figure: 1---and solid pulse laser; 2---long-range LIBS electro-optical system; 3---fiber spectrometer; 4---laser range finder; 5---test site; 6---distant object; 7---sample A; 8---sample B; 9---sample C; 10---laboratory.

Embodiment

As shown in Figure 1, long-range LIBS testing apparatus comprises solid pulse laser 1, long-range LIBS electro-optical system 2, fiber spectrometer 3 and laser range finder 4 to the principle of this patent.

Step 1, complete test site distant object LIBS spectra collection

In test site 5, set up long-range LIBS testing apparatus, the domain test personnel between long-range LIBS testing apparatus and distant object 6 are unapproachable (for example chemical contamination zone, the dangerous geographical environment such as precipice etc.).The laser pulse that solid pulse laser 1 sends focuses on and excites distant object 6 to induce formation LIBS spectral signal to receive and be kept in fiber spectrometer 3 through long-range LIBS electro-optical system 2 through long-range LIBS electro-optical system 2.With the laser range finder 4 carried on proving installation, measure the distance L of distant object 6 from long-range LIBS testing apparatus simultaneously, in order to improve reliability and to eliminate disturbance, 100 LIBS spectroscopic datas that laser pulse is induced average, and obtain the average LIBS spectroscopic data of distant object 6.According to the average LIBS curve of spectrum, the essential element that obtains distant object 6 forms and element X spectral line I to be measured, II, line strength T that III is corresponding _I, T _II, T _III.

Step 2, laboratory sample are demarcated

The essential element of the distant object 6 obtained according to step 1 forms, selection contains three kinds of compounds of element X to be measured and distant object 6 chief component elements, and these three kinds of compounds are prepared to three sample A with different ratio row, B, C, measure the quality of each compound in sample with balance, calculate respectively A according to molecular formula, B, the degree K of element to be measured in C _A, K _B, K _C.

In laboratory 10, the mode the same with test site 5 installs long-range LIBS testing apparatus, and now the tester can place sample A7 on the long-range LIBS testing apparatus L of distance position far away.100 LIBS spectroscopic datas that sample A7 is gathered average, and obtain element X spectral line I to be measured, II, line strength T of III _IA, T _IIA, T _IIIA.

Similarly, use the same method, sample B8 is obtained to element X spectral line I to be measured, II, line strength T of III _IB, T _IIB, T _IIIB; Sample C9 is obtained to element X spectral line I to be measured, II, line strength T of III _IC, T _IIC, T _IIIC.

The line strength of take is ordinate, and the degree of element X to be measured is horizontal ordinate, according to coordinate points (K _A, T _IA), (K _B, T _IB), (K _C, T _IC) carry out linear fit, draw the fitting a straight line equation T (K) of element X spectral line I to be measured _I; Use similar method, obtain the fitting a straight line equation T (K) of element X spectral line II to be measured _IIAnd the fitting a straight line equation T (K) of spectral line III _III.

Step 3, multiline weighted method are quantitatively calculated the degree K of element X to be measured.

The T obtained according to step 1 _IAnd the fitting a straight line equation T (K) of the spectral line I that obtains of step 2 _I, can obtain the degree K based on spectral line I gained of element X to be measured _I.Similarly, according to T _IIWith T (K) _II, can obtain the degree K based on spectral line II gained of element X to be measured _II; According to T _IIIWith T (K) _III, can obtain the degree K based on spectral line III gained of element X to be measured _III.

K _I, K _II, K _IIIDegree of confidence and three line strength T _I, T _II, T _IIIWeight be directly proportional, according to following formula, quantitatively calculate the degree K of element X to be measured:

$K=\frac{T_I}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_I+\frac{T_{\mathrm{II}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_{\mathrm{II}}+\frac{T_{\mathrm{III}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_{\mathrm{III}}=\frac{T_I{K}_I+T_{\mathrm{II}}{K}_{\mathrm{II}}+T_{\mathrm{III}}{K}_{\mathrm{III}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}.$

Claims (1)

1. remote laser induced breakdown spectroscopy quantitative elementary analysis method of demarcating based on the weighting multiline is characterized in that comprising following three steps:

Step 1, complete test site distant object LIBS spectra collection

In test site (5), set up long-range LIBS testing apparatus, between long-range LIBS testing apparatus and distant object (6), be the unapproachable zones of tester such as chemical contamination zone, precipice or dangerous geographical environment, the laser pulse that solid pulse laser (1) sends focuses on through long-range LIBS electro-optical system (2) and excites distant object (6) to induce formation LIBS spectral signal to receive and be kept in fiber spectrometer (3) through long-range LIBS electro-optical system (2); With the laser range finder carried on proving installation (4), measure the distance L of distant object (6) from long-range LIBS testing apparatus simultaneously, in order to improve reliability and to eliminate disturbance, 100 LIBS spectroscopic datas that laser pulse is induced average, and obtain the average LIBS spectroscopic data of distant object (6); According to the average LIBS curve of spectrum, the essential element that obtains distant object (6) forms and element X spectral line I to be measured, II, line strength T that III is corresponding _I, T _II, T _III

Step 2, laboratory sample are demarcated

The essential element of the distant object (6) obtained according to step 1 forms, selection contains three kinds of compounds of element X to be measured and distant object (6) chief component element, and these three kinds of compounds are prepared to three sample A with different ratio row, B, C, measure the quality of each compound in sample with balance, calculate respectively A according to molecular formula, B, the degree K of element to be measured in C _A, K _B, K _C

In laboratory (10), the mode the same with test site (5) installs long-range LIBS testing apparatus, and now the tester can place sample A(7 on the long-range LIBS testing apparatus L of distance position far away); To sample A(7) 100 LIBS spectroscopic datas gathering average, and obtain element X spectral line I to be measured, II, line strength T of III _IA, T _IIA, T _IIIA

Similarly, use the same method, to sample B(8) acquisition element X spectral line I to be measured, II, line strength T of III _IB, T _IIB, T _IIIB; To sample C(9) acquisition element X spectral line I to be measured, II, line strength T of III _IC, T _IIC, T _IIIC

The line strength of take is ordinate, and the degree of element X to be measured is horizontal ordinate, according to coordinate points (K _A, T _IA), (K _B, T _IB), (K _C, T _IC) carry out linear fit, draw the fitting a straight line equation T (K) of element X spectral line I to be measured _I; Use similar method, obtain the fitting a straight line equation T (K) of element X spectral line II to be measured _IIAnd the fitting a straight line equation T (K) of spectral line III _III

Step 3, multiline weighted method are quantitatively calculated the degree K of element X to be measured

The T obtained according to step 1 _IAnd the fitting a straight line equation T (K) of the spectral line I that obtains of step 2 _I, can obtain the degree K based on spectral line I gained of element X to be measured _ISimilarly, according to T _IIWith T (K) _II, can obtain the degree K based on spectral line II gained of element X to be measured _II; According to T _IIIWith T (K) _III, can obtain the degree K based on spectral line III gained of element X to be measured _III

K _I, K _II, K _IIIDegree of confidence and three line strength T _I, T _II, T _IIIWeight be directly proportional, according to following formula, quantitatively calculate the degree K of element X to be measured:

$K=\frac{T_I}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_I+\frac{T_{\mathrm{II}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_{\mathrm{II}}+\frac{T_{\mathrm{III}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}{K}_{\mathrm{III}}=\frac{T_I{K}_I+T_{\mathrm{II}}{K}_{\mathrm{II}}+T_{\mathrm{III}}{K}_{\mathrm{III}}}{T_I+T_{\mathrm{II}}+T_{\mathrm{III}}}.$

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