CN102590157B - Element spectrum analysis method and laser element exploration equipment adopting same - Google Patents

Abstract

The invention belongs to the field of spectrum analysis and detection, and in particular relates to an element spectrum analysis method and laser element exploration equipment adopting the method. The present invention aims to solve the technical problems that the current atomic emission spectrum analysis method for elements has defects, and the intensity of the laser light source on the currently used laser element exploration equipment is not stable enough and is not convenient to carry, and provides an element spectrum analysis method and adopts the method. Laser element exploration equipment. An element spectrum analysis method includes a qualitative analysis method and a quantitative analysis method for the atomic emission spectrum line of a sample to be tested. A laser element prospecting device includes a laser light source system, a spectrum acquisition system, and a signal processing module. The element spectrum analysis method disclosed by the invention overcomes the defects of the previous analysis methods. The laser energy intensity output by the device disclosed by the invention is stable, and the device is small in size and light in weight, and is very suitable for field operations.

Description

Element spectrum analysis method and laser element exploration equipment using the method

technical field

The invention belongs to the field of spectrum analysis and detection, and in particular relates to an element spectrum analysis method and laser element exploration equipment adopting the method.

Background technique

In industrial production and scientific research, it is often necessary to conduct qualitative and quantitative detection and analysis of chemical elements of related materials and minerals. Traditional materials and ore detection and analysis methods mainly include chemical assay, atomic absorption method and inductively coupled plasma emission spectrometry. Among them, chemical analysis method and atomic absorption method need to collect samples from the field, require a long analysis time and cumbersome operating procedures, and are prone to secondary pollution, so they are limited to laboratory analysis; inductively coupled plasma emission spectrometry has high sensitivity , can measure multiple elements at the same time, but requires complex pretreatment of the sample, the amount of reagents is also large, and the plasma torch is easily contaminated. At present, the dominant method in the field exploration industry at home and abroad is X-ray fluorescence spectrometry (XRF), which uses the principle of X-ray fluorescence energy dispersion or wavelength dispersion. Perform direct detection and analysis, but its ability to identify light elements (such as Mg, Al, Si, P, S, etc.) It must be in direct contact with the sample to be tested, and telemetry cannot be realized. In addition, X-rays have radiation hazards, and long-term use is likely to cause various diseases, all of which limit the further promotion of this method.

Laser-induced breakdown spectroscopy (laser induced breakdown spectroscopy) referred to as LIBS, is a laser ablation spectroscopy analysis technology, which has the advantages of no need for sample pretreatment, fast measurement speed, high sensitivity, less destructive to samples, simultaneous analysis of multiple elements, It has the advantages of strong identification ability for light elements (such as Mg, Al, Si, P, S, etc.), safety and no radiation, and remote measurement. Laser-induced breakdown spectroscopy is based on pulsed laser technology. A beam of high-energy laser is focused on the surface of the substance to be analyzed, and part of the substance at the focus is ablated to generate high-temperature plasma. The temperature of the plasma rises to several thousand degrees. produce more charged ions. The electric lines of each element in the plasma form a continuous background line, which takes hundreds of nanoseconds; then the atomic emission lines of each element in the plasma are formed, and the atomic emission lines contain the characteristic information of each element. Different elements Corresponding to the respective atomic emission lines, the intensity of the line is approximately proportional to the concentration of the element, and this process lasts for several microseconds, which is an important part of qualitative analysis, especially quantitative analysis of elements. The type of elements contained in the sample can be determined by analyzing the atomic emission spectrum; the relative content of each element in the sample can be quantitatively analyzed by analyzing the intensity ratio between the spectral lines. The free calibration method well known in the industry is used in the quantitative analysis of elements, that is, the concentration of each component is calculated directly according to the relative intensity of the atomic emission spectrum obtained by normalization, which can avoid the variation of different types of ore substrates caused interference. When calculating the relative intensity of the spectral line, the peak height of the spectral line is used as the relative intensity of the spectral line.

When the quantitative analysis method uses the free calibration method to analyze the element concentration, the measurement accuracy of the free calibration method is improved by improving the calculation accuracy of relevant intermediate calculation parameters (plasma temperature, electron density, spectral line intensity, etc.). When calculating the plasma temperature, the Saha-Boltzmann multi-line diagram method is used instead of the commonly used Boltzmann oblique method, and the monovalent ion spectrum and neutral atomic spectrum of the same element are changed through the Saha equation to determine the temperature. Because the emission lines from different ionization states are selected, and their upper energy levels have a larger energy level difference, the calculation of temperature has higher accuracy. The Saha transformation needs to measure the electron density of the plasma. Here, the electron density is calculated by analyzing the Stark broadening of the emission line. The main linetype of spectral line Stark broadening is Lorentzian type, and Lorentzian contour linetype fitting is used to correct the spectral linetype, which can avoid the interference caused by overlapping spectral lines, improve the calculation accuracy of spectral peak half maximum width, and indirectly improve the measurement precision.

At present, the qualitative analysis of elements still needs to use the naked eye to find the atomic emission spectrum peak, and then search and compare it through the atomic spectrum database of the National Institute of Standards and Technology (NIST). The judgment of position is often not accurate enough, making it impossible to realize accurate qualitative analysis of unknown mineral samples; in quantitative analysis, the spectral peak height is used to represent the relative intensity of atomic emission lines, resulting in unreliable analysis results; the currently used LIBS detection system has laser The intensity is not stable enough. When the emitted laser ablates the sample, the intensity of the atomic emission spectrum radiated by the plasma generated by the sample is also unstable, which affects the accuracy of quantitative analysis; the currently formed LIBS detection system is generally It consists of a Q-switched Nd:YAG laser pumped by a xenon lamp, a spectrometer, a signal generator, a data acquisition and signal processing system, etc. It is large in size and needs 220V mains power supply, which limits its mobility and is not convenient for field work or Take it with you during site inspections.

Contents of the invention

The present invention aims to solve the technical problems of inaccurate analysis results caused by defects in the current atomic emission spectrum analysis method for elements, and the technical problems that the intensity of the laser light source on the currently used laser element exploration equipment is not stable enough and the carrying is not convenient enough, and provides an element spectrum analysis method. Method and laser element prospecting equipment using the method.

The element spectrum analysis method of the present invention adopts the following technical scheme to realize: a kind of element spectrum analysis method, comprises the qualitative analysis method that the atomic emission spectrum line of the sample to be measured is carried out and adopts the quantitative analysis method of free calibration method; The qualitative analysis method includes the following steps: (a) calculate the second derivative of the atomic emission spectrum of the sample; (b) judge the result of the second derivative of the spectral line according to the threshold judgment standard as follows: Minimum point:

Only keep the points that are smaller than the threshold after the second derivative, and the standard deviation is the standard deviation of the data obtained after the second derivative of the spectral line; (c) For the points that are smaller than the threshold, use the three-point comparison method to determine the minimum value point, the minimum value point is the characteristic peak corresponding to the original spectral line; (d) compare the selected characteristic peak with the NIST atomic emission spectrum database, and calibrate the element type corresponding to each spectral line; use the free calibration method The quantitative analysis method uses the integrated intensity of the spectral peak area to represent the relative intensity when calculating the relative intensity of the emission spectrum, and uses the LIBS spectral line correction method to correct the influence of spectral line broadening when calculating the spectral peak area.

In the qualitative analysis method, the second derivative is calculated for the collected LIBS spectral lines, as shown in Figure 1(b), according to the properties of the second derivative, the peak is located at the minimum value. For the weak peak on the base of the original spectral line, because of its slow change, the second-order derivative will become a peak or a smooth line with a small amplitude. Set a threshold, and the minimum point greater than the threshold is regarded as caused by the slowly changing false peak on the substrate, and will not be considered; only the part where the second order derivative is smaller than the threshold is considered, as shown in Figure 1 (c); compare with three points The minimum value point is determined by the method, which is the peak location of the original spectral line, as shown in Figure 1(d). In order to suppress meaningless false peaks on the substrate as much as possible without missing true peaks, it is necessary to select an appropriate threshold to obtain a good peak finding effect. A threshold that is too low will find many spurious or statistically insignificant peaks on the substrate, while a threshold that is too high will miss meaningful true peaks. This method is based on a large number of experiments, and the selected threshold value fluctuates up and down based on the standard deviation (Stanard Deviation, SD) of the data. After experiments, it is found that when the standard deviation of the data is large, taking the standard deviation as the threshold can suppress false peaks to the greatest extent without missing the true peak; when the standard deviation is small, the threshold needs to be appropriately increased to avoid false peaks on the substrate. The peak is misrecognized, and the smaller the SD is, the larger the multiple needs to be increased to obtain a good peak finding effect. This method can well eliminate the influence of background noise and improve the precision of qualitative analysis. The three-point comparison method is widely used in the field of signal analysis and is common knowledge of those skilled in the art.

Quantitative analysis of elements adopts the free calibration method well known in the industry. When calculating the relative intensity of the emission spectrum, the peak area is used instead of the peak height. Compared with the traditional analysis method that only relies on the peak height to judge the peak intensity, this method can effectively improve the accuracy of the analysis results. However, when this method is applied to the analysis of the intensity of atomic emission lines, the following problems will occur, that is, the broadening of individual lines will cause changes in the area of the spectral peaks, as shown in Figure 2 for lines a and b, the peak height of line a is less than B line, but due to broadening, the peak area of a line is larger than that of b line, resulting in inaccurate measurement results. Therefore, when calculating the spectral peak area, it is necessary to use the LIBS spectral line correction method to correct the influence of spectral line broadening and improve the calculation accuracy of the relative intensity of spectral lines.

The laser element exploration equipment disclosed in the present invention is realized by adopting the following technical scheme: a laser element exploration equipment adopting an element spectrum analysis method, including a laser light source system, a spectrum acquisition system, a signal processing module including a photoelectric converter and a computer system ; The output end of the photoelectric converter is connected with the input end of the computer system; The laser light source system includes a laser head, a laser power supply connected to the laser head, a trigger connected to the laser power supply, and a power supply connected to the trigger The spectrum acquisition system includes a micro-focusing system, a spectrometer connected to the micro-focusing system through an optical fiber and connected to a power supply, and the optical fiber is connected to the input end of the spectrometer; an angle-adjustable focusing lens is provided along the optical path of the laser head The output end of the spectrometer is connected with the input end of the photoelectric converter; the output end of the computer system is connected with a display screen; the computer system in the signal processing module, with the support of corresponding software, adopts the described element spectrum analysis method to collect the The atomic emission spectrum is analyzed, and the analysis results are output to the display.

The laser element prospecting equipment also includes a closed-loop energy negative feedback laser energy stabilization system, the closed-loop energy negative feedback laser energy stabilization system includes an angle-adjustable beam splitter prism and a beam splitter arranged between the laser head and the focusing lens The detection device matched with the prism, the feedback circuit connected with the detection device, the feedback circuit is connected with the laser power supply, the detection device includes a thermopile detector and a computer control system connected with the thermopile detector; the signal output of the thermopile detector terminal is connected with the signal input end of the computer control system, and the signal output end of the computer control system is connected with the feedback circuit; the closed-loop energy negative feedback type laser energy stabilization system adopts the following method to control the pulsed laser intensity output by the laser head: Part of the pulsed laser light emitted by the laser head is reflected to the thermopile detector by the beam splitter. The thermopile detector converts the collected optical signal of the pulsed laser into an electrical signal and inputs it to the computer control system. The computer control system is supported by the corresponding software. Calculate the intensity of the collected pulsed laser energy that has been converted into an electrical signal. During the calculation, the integrated intensity of the spectral peak area of the pulsed laser is used to represent the energy intensity of the pulsed laser, and the calculation result is compared with the rated laser intensity output by the laser head. The values are compared, and the computer control system inputs the electrical signal of the difference obtained after the comparison to the feedback circuit, and the feedback circuit automatically adjusts the pumping voltage of the laser power supply according to the input difference signal to stabilize the pulsed laser energy.

The laser element exploration equipment also includes a whole body, the whole body includes a hand-held body and a suitcase connected with the hand-held body; the laser head, micro-focusing system, focusing lens and detection device are arranged on the hand-held Inside the fuselage; the laser power supply, signal processing module, feedback circuit, trigger, power supply, and spectrometer are set inside the suitcase; the power supply is a battery, the optical fiber is set inside the overall fuselage, and the hand-held fuselage is along the optical path of the laser head A conical measuring head is provided at one end of the device, and the micro-focusing system is arranged near the conical measuring head; the display screen is a micro-display screen and is arranged on the outside of the hand-held body, and a handle is also provided on the outside of the hand-held body.

The power supply supplies power to the trigger and the spectrometer, and the trigger is used to control the pumping voltage of the laser power supply, which acts as a switch; the computer system is equipped with a storage battery, which can supply power to the entire signal processing module. When working, aim the laser head at the sample, start the laser power supply through the trigger, the laser power supply controls the laser head to emit pulsed laser, the pulsed laser is focused by the focusing lens, and irradiates the surface of the sample to be tested, so that the sample is excited to generate plasma at the focused part The atomic emission line radiated by the plasma is received by the micro-focusing system and transmitted to the spectrometer through an optical fiber. The spectrometer splits it and transmits the spectral signal to the signal processing module. The converter converts the optical signal into a corresponding electrical signal. With the support of corresponding software, the computer system uses the element spectrum analysis method to conduct qualitative and quantitative analysis on the spectral signal converted into an electrical signal, and displays the analysis results on the display. Those skilled in the art can easily write corresponding software according to the element spectrum analysis method disclosed in the present invention.

When using LIBS for element exploration, the influence of factors such as laser energy instability and lens contamination will cause certain fluctuations in the plasma generated by the pulsed laser, and the intensity of the spectral signal will vary, which will greatly affect the quantitative analysis. accuracy. In order to overcome this shortcoming, a closed-loop energy negative feedback laser energy stabilization system is designed to stabilize the pulsed laser energy. The specific implementation is as follows: a beam splitting prism and a detection device matched with the beam splitting prism are placed in the laser output light path, the beam splitting prism reflects a part of the laser light to the detection device, and the detection device is used to detect the output pulsed laser energy. The corresponding feedback signal is input into the feedback circuit, and the pumping voltage in the laser power supply is adjusted in real time through the feedback circuit to stabilize the output pulse laser energy. A closed-loop control system is formed among the laser light source system, the detection device and the feedback circuit. The feedback circuit can be implemented in various structures, and related technologies are well known to those skilled in the art. The computer control system in the detection device is equipped with a battery to supply power to the entire detection device; when the electrothermal pile detector collects laser energy, the sampling rate is 200000S/s, as shown in Figure 4 for the collected pulse energy signal. When calculating the pulsed laser energy, in order to improve the calculation accuracy, the integrated intensity of the spectral peak area is used instead of its peak height to represent the energy of the pulsed laser, that is, the difference between the shaded area in Figure 4 and the area occupied by the background signal, the background The strength of the signal can be represented by the average of the flatter parts on both sides of the spectral peak. Comparing the pulse energy calculated by this method with the result measured by the power meter, the result is shown in Figure 5. It can be seen from Figure 5 that there is almost a linear relationship between the two, and the correlation is relatively high. The thermopile detector converts the detected pulsed laser energy signal into an electrical signal and then inputs it to the computer control system. With the support of the corresponding software, the computer control system _compares the intensity value I of the input pulsed laser energy converted into an electrical signal with _The rated pulse laser output intensity I of the laser light source system used is compared, and the electrical signal reflecting the _{difference between} I and _I is input to the feedback circuit, and the feedback circuit controls the pumping voltage of the laser power supply according to the input difference electrical signal. Real-time adjustment, if the output laser intensity is greater than the rated value, the feedback circuit controls the pumping voltage of the laser power supply to reduce, so that the output laser intensity of the laser head decreases until it is close to the rated value; when the output laser intensity is lower than the rated value, the feedback circuit controls The pumping voltage of the laser power supply increases to increase the laser intensity output by the laser head until it is close to the rated value. The invention can control the instability of pulsed laser output energy within ±2%. Figure 6 shows the pulse energy stability test chart when the laser outputs 100 continuous laser pulses before and after using the closed-loop energy negative feedback laser energy stabilization system under the same parameters. It can be seen from FIG. 6 that the closed-loop energy negative feedback laser energy stabilization adopted in the present invention can greatly improve the stability of laser output energy, thereby improving the accuracy and stability of quantitative analysis.

The various components of the LIBS detection system are set inside the overall fuselage, and the trigger and spectrometer are powered by the battery, which is convenient to carry around in the field or on-site exploration; the angles of the focusing lens and the micro-focusing system inside the handheld fuselage are uniform. It can be fine-tuned to ensure that the focus of the outgoing laser light after being focused by the focusing lens is located in the center of the conical measuring head, so that the sample is excited into plasma, and the micro-focusing system can receive atomic emission lines with a high enough signal-to-noise ratio; the overall machine There are switches on the outside of the body to control the internal components, which is convenient for the operation of the whole equipment; the setting of the handle is conducive to the operator's grasp. The use of a tapered measuring head helps to align the body with the sample; the power supply uses a battery, which is very simple to charge and discharge, and can be replaced at any time, which is convenient for carrying when going out; Displays the analysis results.

The laser light source system, spectrum acquisition system, signal processing module and detection device described in the present invention are all known technologies, and can have various structures and related models for selection, and are easy to purchase on the market.

The qualitative analysis method disclosed in the present invention overcomes the problems of inaccurate peak finding, slow analysis process and inaccurate results in previous similar methods; The LIBS spectral line correction method corrects the influence of spectral line broadening and improves the accuracy of quantitative analysis results. The closed-loop energy negative feedback laser energy stabilization system adopted makes the laser emitted by the laser light source system more stable, and the spectrum emitted by the plasma generated during sampling is more stable, which improves the reliability of quantitative analysis results. Due to its small volume and light weight, the present invention can display the results in real time, and is very suitable for field operations.

Description of drawings

Figure 1 Schematic diagram of the qualitative analysis method. Figure a is the sample atomic emission spectrum line measured by the spectrometer; Figure b is the result of calculating the second derivative of the measured spectrum; Figure c is the peak left after removing points greater than the threshold according to the threshold judgment standard; Figure d It is the peak position of the original spectral line found according to the three-point comparison method, and the solid point in the figure represents the peak position.

Figure 2. Effect of peak broadening in calculating peak area.

Fig. 3 Schematic diagram of the structure of the laser element exploration equipment of the present invention.

Fig. 4 Schematic diagram of the pulsed laser energy signal collected by the thermopile detector and the area integral of the laser energy.

Figure 5 Schematic diagram of the comparison between the laser intensity calculated by using the integrated intensity of the spectral peak area and the result measured by the power meter. The solid dots in the figure indicate the corresponding relationship between the laser intensity measured by the power meter and the corresponding peak area, and the oblique lines indicate the corresponding relationship between the integrated intensity of the peak area and the laser intensity.

Figure 6. The pulse energy stability test chart when the laser outputs 100 continuous laser pulses before and after using the closed-loop energy negative feedback laser energy stabilization system. Picture a is before use and picture b is after use. Solid points indicate the measured energy intensity of the pulsed laser.

Fig. 7 The present invention is to the detection result of four kinds of samples. Picture a is brass, picture b is aluminum plate, picture c is solar silicon plate, picture d is magnesium borate sheet.

1-laser head, 2-detection device, 3-beam splitting prism, 4-focusing lens, 5-taper measuring head, 6-miniature focusing system, 7-optical fiber, 8-miniature display, 9-handle, 10-signal Processing module, 11-power supply, 12-feedback circuit; 13-laser power supply, 14-trigger, 15-spectrometer, 16-handheld body, 17-suitcase, 18-sample.

Detailed ways

An elemental spectral analysis method, including a qualitative analysis method for the atomic emission line of a sample to be tested and a quantitative analysis method using a free calibration method; the qualitative analysis method includes the following steps: (a) analyzing the atomic emission line of the sample Calculate the second derivative of the spectral line; (b) For the result of the second derivative of the spectral line, judge the minimum value point after the derivative according to the threshold judgment standard specified below:

Only keep the points that are smaller than the threshold after the second derivative, and the standard deviation is the standard deviation of the data obtained after the second derivative of the spectral line; (c) For the points that are smaller than the threshold, use the three-point comparison method to determine the minimum value point, the minimum value point is the characteristic peak corresponding to the original spectral line; (d) compare the selected characteristic peak with the NIST atomic emission spectrum database, and calibrate the element type corresponding to each spectral line; use the free calibration method The quantitative analysis method uses the integrated intensity of the spectral peak area to represent the relative intensity when calculating the relative intensity of the emission spectrum, and uses the LIBS spectral line correction method to correct the influence of spectral line broadening when calculating the spectral peak area.

A laser element prospecting device adopting an element spectrum analysis method, comprising a laser light source system, a spectrum acquisition system, a signal processing module 10 including a photoelectric converter and a computer system; the output end of the photoelectric converter is connected to the input end of the computer system The laser light source system includes a laser head 1, a laser power supply 13 connected to the laser head 1, a trigger 14 connected to the laser power supply 13, and a power supply 11 connected to the trigger 14; the spectrum acquisition system includes a micro focus system 6. A spectrometer 15 connected to the micro-focusing system 6 and connected to the power supply 11 through an optical fiber 7, the optical fiber 7 is connected to the input end of the spectrometer 15; an angle-adjustable focusing lens is provided along the optical path of the laser head 1 4; the output end of the spectrometer 15 is connected with the input end of the photoelectric converter; the output end of the computer system is connected with a display screen 8; the computer system in the signal processing module 10 adopts the described element spectral analysis method under the support of corresponding software The collected atomic emission lines are analyzed, and the analysis results are output to the display screen 8 . It also includes a closed-loop energy negative feedback laser energy stabilization system. The closed-loop energy negative feedback laser energy stabilization system includes an angle-adjustable beam-splitting prism 3 arranged between the laser head 1 and the focusing lens 4, and cooperates with the beam-splitting prism 3. The detection device 2, the feedback circuit 12 connected with the detection device 2, the feedback circuit 12 is connected with the laser power supply 13; the detection device 2 comprises a thermopile detector and a computer control system connected with the thermopile detector; the thermopile detector The signal output end of the computer control system is connected with the signal input end of the computer control system, and the signal output end of the computer control system is connected with the feedback circuit 12; the closed-loop energy negative feedback type laser energy stabilization system adopts the following method to the pulse output by the laser head 1 Laser intensity control: Part of the pulsed laser light emitted by the laser head 1 is reflected by the beam splitter 3 to the thermopile detector 2, and the thermopile detector 2 converts the collected optical signal of the pulsed laser into an electrical signal and inputs it to the computer control system. With the support of corresponding software, the computer control system calculates the intensity of the collected pulsed laser energy that has been converted into an electrical signal. During the calculation, the integrated intensity of the peak area of the pulsed laser spectrum is used to represent the energy intensity of the pulsed laser, and the calculated result Compared with the value of the rated laser intensity of the laser head 1, the computer control system inputs the electrical signal of the difference obtained after the comparison to the feedback circuit 12, and the feedback circuit 12 automatically adjusts the pumping voltage of the laser power supply 13 according to the input difference signal. Stabilize the pulsed laser energy. Also comprise an integral body, integral body comprises hand-held body 16 and the suitcase 17 that is connected with hand-held body 16; The inside of the fuselage 16; the laser power supply 13, the signal processing module 10, the feedback circuit 12, the trigger 14, the power supply 11, and the spectrometer 15 are arranged inside the suitcase 17; the power supply 11 is a storage battery, and the optical fiber 7 is arranged on the whole fuselage Inside, the hand-held body 16 is provided with a tapered measuring head 5 along one end of the optical path of the laser head, and the miniature focusing system 6 is arranged near the tapered measuring head 5; the display screen 8 is a miniature display and is arranged on the hand-held body On the outside, a handle 9 is also provided on the outside of the hand-held body 16 . The handheld body 16 is connected with the suitcase 17 by a threaded pipe. The laser head 1 is a high voltage trigger laser head. The computer system in the signal processing module 10 adopts a miniature notebook computer. The battery is a 12V battery.

The hand-held body 16 is connected with the suitcase 17 through a threaded pipe, which can facilitate the movement of the hand-held body and facilitate the alignment of the target sample during detection; the computer system adopts a miniature notebook computer, which further reduces the volume of the device; 12V battery Small size, fast charging; high-voltage trigger laser head has the advantages of high reliability and low standby current.

During specific implementation, the laser light source system used is a portable high-power Nd:YAG laser system, and the model used in the laser head 1 is a high-voltage trigger laser head of LMS-367; the model used by the trigger 14 is MK-367HC; the laser power supply 13 The model used is MK-106.20, the spectrometer 15 is Avantes AvaSpec-2048-USB2 spectrometer produced by Avantes Company of the Netherlands, and the optical fiber 7 is an all-silica optical fiber produced by Avantes Company of the Netherlands, with a numerical aperture of 0.22 and a fiber core diameter of 600 microns.

Fig. 7 is the analysis result displayed on the micro-display screen 8 after the present invention is specifically applied to actual exploration. Each solid point in the figure represents the peak value of the atomic emission spectrum of each element in the sample 18 analyzed by the signal processing module. The invention can accurately analyze the composition of the sample and give the composition of each element contained in the sample.

Claims (10)

1. an element spectrum analysis method, comprises the method for qualitative analysis that the atomic emission line of testing sample is carried out and the quantitative analysis method that adopts free scaling method; It is characterized in that, described method for qualitative analysis comprises the following steps: (a) atomic emission line of sample is asked to second derivative; (b), for the result after spectral line second derivative, according to the stimulus threshold criterion of following regulation, judge the minimum point after difference quotient:

Only retain the point that is less than threshold value after second derivative, described standard deviation is the standard deviation of the data obtained after spectral line second derivative; (c) to being less than the point of threshold value, adopt triangle test to determine minimum point wherein, this minimum point is the characteristic peak of corresponding former spectral line; (d) characteristic peak of selecting and NIST atomic emission spectrum database are compared, the element kind that each spectral line is corresponding is demarcated; Adopt the quantitative analysis method of free scaling method when calculating the relative intensity of the spectral line of emission, to adopt the integrated intensity of spectrum peak area to represent relative intensity, when calculating spectrum peak area, adopt the impact of LIBS spectral line modification method innovation spectrum line broadening.

2. adopt a laser element exploring equipment for element spectrum analysis method as claimed in claim 1, comprise laser source system, spectra collection system, include the signal processing module (10) of photoelectric commutator and computer system; The output terminal of photoelectric commutator is connected with the input end of computer system; Described laser source system comprises laser head (1), the Laser Power Devices (13) that are connected with laser head (1), the trigger (14) being connected with Laser Power Devices (13) and the power supply (11) being connected with trigger (14); Spectra collection system comprises miniature focusing system (6), the spectrometer (15) that is connected and is connected with power supply (11) with miniature focusing system (6) by optical fiber (7), and described optical fiber (7) is connected with the input end of spectrometer (15); Light path along laser head (1) is provided with the adjustable condenser lens of angle (4); Spectrometer (15) output terminal is connected with the input end of photoelectric commutator; Computer system output terminal is connected with display screen (8); It is characterized in that, the computer system in signal processing module (10), under the support of corresponding software, adopts described element spectrum analysis method to analyze collected atomic emission line, and exports analysis result to display screen (8).

3. laser element exploring equipment as claimed in claim 2, characterized by further comprising closed loop energy negative feedback laser energy systems stabilisation, described closed loop energy negative feedback laser energy systems stabilisation comprises the feedback circuit (12) that is arranged on laser head (1) Amici prism (3) adjustable with angle between condenser lens (4), the sniffer (2) matching with Amici prism (3), is connected with sniffer (2), and feedback circuit (12) is connected with Laser Power Devices (13), sniffer (2) comprises thermopile detector and the computer control system being connected with thermopile detector, the signal output part of thermopile detector is connected with the signal input part of computer control system, and the signal output part of computer control system is connected with feedback circuit (12), described closed loop energy negative feedback laser energy systems stabilisation is adopted with the following method the pulse laser intensity of laser head (1) output is controlled: the partial pulse laser that laser head (1) sends reflexes to thermopile detector (2) through Amici prism (3), thermopile detector (2) is converted to the light signal of the pulse laser collecting electric signal and inputs to computer control system, computer control system is carried out intensity calculating to the pulsed laser energy that is converted into electric signal collecting under the support of corresponding software, during calculating, adopt the integrated intensity of the spectrum peak area of pulse laser to carry out the energy intensity of indicating impulse laser, and the numerical value of the specified laser intensity of result of calculation and laser head (1) is compared, computer control system inputs to feedback circuit (12) by the electric signal of relatively rear gained difference, feedback circuit (12) is adjusted the pumping voltage of Laser Power Devices (13) so that pulsed laser energy is stable automatically according to the difference signal of input.

4. laser element exploring equipment as claimed in claim 3, characterized by further comprising an integral body, and integral body comprises hand-held fuselage (16) and the suitcase (17) being connected with hand-held fuselage (16); Laser head (1), miniature focusing system (6), condenser lens (4) and sniffer (2) are arranged on hand-held fuselage (16) inside; Laser Power Devices (13), signal processing module (10), feedback circuit (12), trigger (14), power supply (11), spectrometer (15) are arranged on suitcase (17) inside; Described power supply (11) is accumulator, and optical fiber (7) is arranged on integral body inside, and hand-held fuselage (16) is provided with taper measuring head (5) along one end of laser head (1) light path, and miniature focusing system (6) is arranged near taper measuring head (5); Described display screen (8) is for miniature display screen and be arranged on hand-held fuselage outer side, and hand-held fuselage (16) outside is also provided with handle (9).

5. laser element exploring equipment as claimed in claim 4, is characterized in that hand-held fuselage (16) is connected by threaded line pipe with suitcase (17).

6. laser element exploring equipment as claimed in claim 2 or claim 3, is characterized in that described laser head (1) is high pressure trigger-type laser head.

7. laser element exploring equipment as claimed in claim 4, is characterized in that described laser head (1) is high pressure trigger-type laser head.

8. laser element exploring equipment as claimed in claim 2 or claim 3, is characterized in that the computer system in described signal processing module (10) adopts mini-notebook computer.

9. laser element exploring equipment as claimed in claim 4, is characterized in that the computer system in described signal processing module (10) adopts mini-notebook computer.

10. laser element exploring equipment as claimed in claim 4, is characterized in that described accumulator is 12V accumulator.

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