Time-resolved LIBS (laser-induced breakdown spectroscopy) system and sample component analysis method and product thereof

Abstract

The invention discloses a time-resolved LIBS (laser-induced breakdown spectroscopy) system and a sample component analysis method and product thereof, and relates to the field of laser-induced breakdown spectroscopy. After the sample is irradiated by the ablation laser, plasma is generated; in the plasma expansion and cooling process, excited state atoms and ions are subjected to energy level transition, and a characteristic radiation spectrum is released; the delay control module sets different delay time so as to control the working time interval of the laser generator and the spectrograph; the spectrograph receives the characteristic radiation spectrums at different delay times by using an optical fiber probe, stimulates the characteristic radiation spectrums at the integration time, and determines characteristic radiation spectral lines of different elements; and the computer analyzes the characteristic radiation spectral lines, determines spectral line intensities of different elements, and determines a component result of the sample in combination with the calibrated spectral line intensities and the element content function curve so as to improve the accuracy of the component result of the sample.

Description

Technical Field

[0001] The present application relates to the field of laser-induced breakdown spectroscopy, and particularly to a time-resolved LIBS system, a method for analyzing sample components thereof, and a product. Background Art

[0002] Laser induced breakdown spectroscopy (LIBS) uses high-energy lasers to generate plasma on the surface of an object, and analyzes the spectral lines of atomic emissions to perform quantitative and qualitative analysis of elements. In the patent with publication number CN103620374B and title "Device and Method for Quantitative Sample Analysis Using Laser Induced Plasma", a device is proposed to perform quantitative sample analysis using this technology. However, there are obvious deficiencies in the accuracy and precision of laser-induced breakdown spectroscopy in quantitative analysis. The main reasons for the low LIBS quantitative accuracy include: the instability of the plasma, the sample matrix effect, the fluctuation of laser energy, the insufficient sensitivity of the detection system, and the superposition of multiple factors such as spectral self-absorption. And the LIBS quantitative accuracy directly affects the accuracy of the results of the components of the sample to be measured. Summary of the Invention

[0003] The purpose of the present application is to provide a time-resolved LIBS system, a method for analyzing sample components thereof, and a product, so as to solve the problem of low accuracy of the results of the components of the sample measured by traditional LIBS technology.

[0004] To achieve the above purpose, the present application provides the following solutions.

[0005] In the first aspect, the present application provides a time-resolved LIBS system, including the following modules.

[0006] A laser generator for emitting ablation laser to a sample on a sample stage.

[0007] After the sample is irradiated by the ablation laser, plasma is generated; during the expansion and cooling process of the plasma, excited atoms and ions undergo energy level transitions, releasing characteristic radiation spectra.

[0008] A delay control module connected to the laser generator and the spectrometer, for setting different delay times to control the working time interval between the laser generator and the spectrometer; the working time interval is determined based on different elements.

[0009] A spectrometer for using an optical fiber probe to receive the characteristic radiation spectra at different delay times, and stimulating the characteristic radiation spectra under an integration time to determine the characteristic radiation spectral lines of different elements.

[0010] A computer, connected to the spectrometer, is used to analyze the characteristic radiation spectral lines, determine the spectral line intensities of different elements, and combine the calibrated spectral line intensity and element content function curve to determine the composition result of the sample; the spectral line intensity is the integral intensity.

[0011] In a second aspect, the present application provides a sample composition analysis method based on the above, including the following steps.

[0012] The delay control module is made to set different delay times to control the working time interval between the laser generator and the spectrometer.

[0013] Receive the characteristic radiation spectral lines of different elements transmitted by the spectrometer; the characteristic radiation spectral lines are determined by stimulating the characteristic radiation spectra at different delay times under the integration time.

[0014] Analyze the characteristic radiation spectral lines, determine the spectral line intensities of different elements, and combine the calibrated spectral line intensity and element content function curve to determine the composition result of the sample; the spectral line intensity is the integral intensity.

[0015] In a third aspect, the present application provides a computer program product, including a computer program which, when executed by a processor, implements the above sample composition analysis method.

[0016] According to the specific embodiments provided by the present application, the present application has the following technical effects: The present application uses a spectrometer to dynamically collect characteristic spectra at different delay times to capture the characteristic radiation spectral lines of different elements within different time windows, thereby reducing the self-absorption effect and improving the accuracy of elemental quantitative analysis.

[0017] By setting the delay time and the integration time, the present application can effectively select the optimal emission stage of the plasma, extract characteristic radiation spectra with high signal-to-noise ratio, achieve precise detection of target elements, and improve the accuracy rate of the sample composition result. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a schematic diagram of the laser-induced laser ablation process of laser breakdown spectroscopy provided by an embodiment of the present application.

[0020] Figure 2 It is a schematic diagram of the structure of a time-resolved LIBS system provided by an embodiment of the present application.

[0021] Figure 3 Schematic diagram of time-resolved laser-induced breakdown spectroscopy provided by an embodiment of the present application.

[0022] Figure 4 Schematic flow diagram of a sample composition analysis method provided by an embodiment of the present application.

[0023] Figure 5 Schematic flow diagram of a time-resolved LIBS matrix effect correction provided by an embodiment of the present application.

[0024] Figure 6 Schematic diagram of the structure of a computer device provided by an embodiment of the present application. Detailed implementation manners

[0025] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0026] To make the purpose, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0027] To solve the problem of low precision in LIBS quantitative analysis, time resolution is used to perform precise calculations on LIBS quantitative analysis to improve its quantitative analysis accuracy. As Figure 1 shown, the ablation process of the LIBS technology is the core link that determines the formation and evolution of the plasma, and has a profound impact on the excitation of elements, the intensity of the emission spectrum, and the analysis accuracy. During the interaction between the laser and the material, multiple physical processes such as the absorption of laser energy, heat conduction, melting, vaporization, plasma generation, and its kinetic evolution are coupled with each other, directly affecting the composition and distribution of the ablation products, and further affecting the electron density, excitation temperature, and spectral emission characteristics of the plasma. The ablation process is complexly affected by laser parameters (such as wavelength, pulse duration, energy density, repetition frequency, etc.), environmental conditions (such as air pressure, medium type), and material properties (such as thermal properties, absorption coefficient, surface roughness), making the ablation mechanism exhibit highly non-linear and dynamic change characteristics. Precise regulation of the ablation process can not only improve the stability of the plasma and the signal-to-noise ratio of the spectral lines, but also reduce the matrix effect and improve the reliability of element quantitative analysis. Therefore, in-depth research on the LIBS ablation process not only helps to optimize experimental parameters, improve detection sensitivity and repeatability, but also lays a solid foundation for expanding its applications in complex environments (such as on-line monitoring, planetary exploration, biomedical analysis, etc.).

[0028] Dynamically collecting the plasma spectral signal using a spectrometer with high time resolution can capture spectral features within different time windows, thereby optimizing the signal acquisition strategy, reducing the self-absorption effect, and improving the accuracy of elemental quantitative analysis. By reasonably setting the delay time and integration time, the optimal emission stage of the plasma can be effectively selected, spectral signals with high signal-to-noise ratio can be extracted, and precise detection of target elements can be achieved. In addition, combined with the Time-Resolved Laser-Induced Breakdown Spectroscopy (TR-LIBS) technology, the formation and evolution mechanism of the plasma can be further studied, providing important theoretical and experimental support for optimizing the laser ablation parameters and improving the quantitative analysis ability of the LIBS technology.

[0029] To improve the quantitative analysis accuracy of the LIBS technology, a high-time-resolution LIBS experimental device is constructed, namely the time-resolved LIBS system provided in this application. This system studies the time-varying spectral evolution law of the plasma. By optimizing the time-resolved acquisition strategy of the spectrometer, the dynamic changes of the electron density, excitation temperature, and spectral emission characteristics of the plasma on different time scales are deeply analyzed. The influence of the integration time on the spectral signal quality is mainly discussed. Based on the experimental data of different delay times and integration windows, the acquisition parameters of the spectrometer are optimized to reduce the matrix effect during the plasma evolution process. A reasonable time-resolved strategy can not only effectively reduce the self-absorption effect and background interference, but also improve the stability and accuracy of elemental quantitative analysis, providing important experimental support and theoretical basis for the application of the LIBS technology in complex matrix environments.

[0030] As Figure 2 shown, the embodiment of this application provides a time-resolved LIBS system, which includes the following modules.

[0031] A laser generator 1 for emitting ablation laser to a sample 3 on a sample stage 2.

[0032] After being irradiated by the ablation laser, the sample 3 generates a plasma; during the expansion and cooling process of the plasma, excited atoms and ions undergo energy level transitions, releasing characteristic radiation spectra.

[0033] A delay control module 4, connected to the laser generator 1 and the spectrometer 5, for setting different delay times to control the working time interval between the laser generator 1 and the spectrometer 5; the working time interval is determined based on different elements.

[0034] A spectrometer 5 for using an optical fiber probe to receive the characteristic radiation spectra at different delay times and stimulating the characteristic radiation spectra under the integration time to determine the characteristic radiation spectral lines of different elements.

[0035] A computer 6, connected to the spectrometer 5, is configured to analyze the characteristic radiation spectral lines, determine the spectral line intensities of different elements, and combine the calibrated spectral line intensity and the element content function curve to determine the composition result of the sample 3; the spectral line intensity is the integrated intensity.

[0036] In practical applications, the laser generator 1 is a neodymium-doped yttrium aluminium garnet (Nd:YAG) laser generator, which can emit high-energy pulsed ablation lasers.

[0037] In practical applications, the delay control module is used to control the working time interval between the spectrometer 5 and the Nd:YAG laser generator, and the delay control module sets the time delay between the laser emission of the laser generator and the light collection of the spectrometer 5.

[0038] In an exemplary embodiment, the present application further includes: a reflecting mirror 7, having an included angle with the laser generator 1, for changing the emission direction of the ablation laser.

[0039] In practical applications, the included angle is 45°.

[0040] In an exemplary embodiment, the present application further includes: a convex lens 8, parallel to the reflecting mirror 7 and located on the reflection light path of the reflecting mirror 7, for focusing the ablation laser and irradiating the focused ablation laser onto the sample 3.

[0041] In an exemplary embodiment, the working time interval is the time interval between the laser emission time of the laser generator 1 and the light collection time of the spectrometer 5.

[0042] In an exemplary embodiment, the plasma includes electrons, ions, atoms, and molecular fragments.

[0043] At any moment, the atom or ion of the element transitions from a high energy level u to a low energy level l level, and the integrated intensity generated by integrating the energy level radiation within the integration time is: ; where is the integrated intensity at the delay time ; is t the instantaneous radiation intensity at the moment of

[0044] In practical applications, the computer 6 is used to analyze and process the information collected by the spectrometer 5, mainly including connecting to the spectrometer 5 through USB, acquiring atomic emission spectra, storing them in the computer 6, obtaining the intensity of the spectral lines of the pre-analyzed elements through comparison with the NIST atomic emission spectral lines, and calculating the composition results of the sample 3 according to the calibrated function curve of the spectral line intensity and the element content.

[0045] The specific process is as follows: The high-energy pulsed ablation laser is incident at a large angle and is adjusted by the mirror 7 to be perpendicular to the sample 3. The convex lens ensures that the high-energy pulsed ablation laser is well focused on the surface of the sample 3, vaporizing the sample 3 in a short time and further ionizing it to form a high-temperature plasma. This plasma contains electrons, ions, neutral atoms, and molecular fragments. During the expansion and cooling of the plasma, the excited atoms and ions undergo energy level transitions, releasing characteristic radiation spectra, which are received by the spectrometer 5 after a specific time interval, and the data is transmitted to the computer 6 for analysis to obtain the composition of the sample 3.

[0046] In this embodiment, the delay control module provides the system time. If the laser generation is taken as the 0 moment, after the high-energy pulsed ablation laser breaks down the sample 3 into plasma (about 150 us), during the expansion and cooling process of the plasma, characteristic radiation spectra are released ( moment), at this time the spectrometer 5 starts to receive signals, as Figure 3 shown, where is the spectral intensity change of element 1 over time, is the spectral integral change of element 1 from time to time period, is the spectral intensity change of element 2 over time; is the spectral integral change of element 2 from time to time period, and t0 - t3 are the excitation integration time points of the element laser-induced breakdown spectroscopy.

[0047] Generally, the lifetime of the laser-induced plasma is about 10 us to 100 us. Research shows that by continuously monitoring the evolution of the unified plasma, it can be found that in the early stage (within 100 ns), the plasma is relatively stable, but small fluctuations may cause drastic changes in the later stage (after 300 ns), resulting in poor repeatability of the emission intensity.

[0048] At a certain moment, when an atom or ion of an element makes a transition from a higher energy level u to a lower energy level l, its energy level radiation intensity is: ; where is the number density of the species corresponding to the u-level excited state, is the transition probability of the u-level energy level.

[0049] The spectrometer 5 stimulates the characteristic spectrum of radiation under an extremely short integration time. The decay curves of different elements and plasmas are different, and there are great differences in the characteristic radiation spectral lines at different time nodes. Therefore, high-precision spectral information acquisition can be achieved.

[0050] The regression algorithm is a data analysis algorithm. By performing regression calculations on the spectral information obtained during the LIBS measurement process, the element content is determined. First, the spectral intensities of different known elements, such as calcium, cobalt, sodium, etc., are measured. After obtaining the characteristic spectral distributions of these elements, they can be calibrated according to the different spectral intensities corresponding to different elements.

[0051] Similarly, other elements in other samples 3 will also have similar spectral intensities. Therefore, the content of the corresponding elements can be obtained through the spectrum.

[0052] As Figure 4 shown, the present application also provides a method for analyzing the composition of a sample, including the following steps.

[0053] S1: Let the delay control module set different delay times to control the working time interval between the laser generator and the spectrometer.

[0054] S2: Receive the characteristic radiation spectral lines of different elements transmitted by the spectrometer; the characteristic radiation spectral lines are determined by stimulating the characteristic radiation spectra at different delay times under the integration time.

[0055] S3: Analyze the characteristic radiation spectral lines, determine the spectral line intensities of different elements, and combine the calibrated spectral line intensity and the element content function curve to determine the composition result of the sample; the spectral line intensity is the integration intensity.

[0056] In an exemplary embodiment, at any moment, the atom or ion of the element transitions from a high energy level u energy level to a low energy level l energy level, and the integration intensity generated by integrating the energy level radiation within the integration time is: ; where is the delay time under the integration intensity; is t the instantaneous radiation intensity at the moment.

[0057] The excitation source of LIBS technology is not constantly stable, and the interaction between the laser and the sample 3 is relatively complex. Therefore, each laser-induced plasma is transient and there are certain differences. Generally, the lifetime of laser-induced plasma is about 10 μs to 100 μs. Research shows that by continuously monitoring the evolution of the same plasma, it can be found that in the early stage (within 100 ns), the plasma is relatively stable, but tiny fluctuations may cause drastic changes in the later stage (after 300 ns), resulting in poor repeatability of the emission intensity, as Figure 3 shown. To avoid the interference of strong bremsstrahlung and recombination radiation, the spectrometer usually starts integrating after 1 μs, making it possible for there to be obvious differences in the plasma during the integration stage. Such differences are mainly reflected in the changes in the instantaneous energy level radiation intensity at different delay times and the different attenuations of energy level radiation during the integration process, ultimately affecting the spectral line intensity detected by the spectrometer. It can be seen that the existing plasma parameter correction methods usually target the correction of instantaneous radiation intensity, while the problem of signal uncertainty caused by the radiation attenuation difference during the integration time is often ignored.

[0058] TR-LIBS realizes the precise analysis of its time-varying evolution process by collecting plasma spectral signals within a specific time window. The formation of laser-induced plasma undergoes a complex kinetic process, including laser ablation, plasma expansion, cooling, and spectral emission, etc., resulting in significant changes in its electron density, excitation temperature, and spectral line intensity over time. In the early stage, the plasma temperature and electron density are relatively high, leading to spectral line broadening and strong self-absorption effects, while in the later stage, the spectral signal may decay due to particle recombination and cooling effects. TR-LIBS technology optimizes the signal quality, reduces matrix effects, and improves the accuracy and stability of element quantitative analysis by adjusting the time delay (Gate Delay) and integration time (Gate Width) of the spectrometer 5 to collect spectra at different stages of plasma evolution. This method not only has significant advantages in reducing background noise and enhancing signal characteristics, but also provides an important means for in-depth study of the formation mechanism and evolution law of plasma.

[0059] The specific working principle is as follows: At a certain moment, when an atom or ion of an element makes a transition from a higher energy level u to a lower energy level l, the energy level radiation intensity can be calculated by the following formula.

[0060] (1) where is the number density of species corresponding to the u-level excited state, is the transition probability of the u-level energy level. Under the condition of local thermodynamic equilibrium (LTE), the number of species in the u-level excited state The relationship with the total number of species is in line with the Boltzmann distribution.

[0061] (2) where K is the Boltzmann constant, U(T) is the partition function at temperature T, and are the statistical weight and excitation energy of the u energy level respectively. Substituting Equation (2) into Equation (1), the radiation intensity The relationship with the total number of species is as follows.

[0062] (3) It should be noted that the radiation intensity obtained by this formula is strictly speaking only the radiation intensity generated when atoms or ions transition to the excited state at a certain moment. However, as the plasma state changes with time, the number and distribution of excited-state substances will also change. Therefore, the change of radiation intensity with time should satisfy the following equation.

[0063] (4) where T(t) is the temperature that changes with time, and 0(t) is all other factors that change with time and affect the radiation intensity (the number of excited-state atoms or ions, the distribution of substances in the plasma, the degree of ionization, etc.).

[0064] In the quantitative analysis of LIBS, since the spectrometer 5 requires an integration time, the integrated radiation intensity is usually used instead of the instantaneous radiation intensity, thus ignoring the uncertainty brought by the change of radiation intensity during the integration stage. Therefore, the more accurate formula for the emission line intensity collected by the LIBS system is as follows.

[0065] (5) where is the delay time, is the integration time. Each time-related function must have a decay coefficient, which must affect the result of the integration function. For the sake of easy understanding and distinction, the following is: will be described as the energy-level radiation (instantaneous radiation intensity) and will be described as the integrated intensity or line intensity (the intensity generated by integrating the energy-level radiation within the integration time).

[0066] In the laboratory, a spectrometer 5 with a high-speed shutter is often used to integrate the energy-level radiation for microseconds or even shorter times. However, the intensity obtained by integration is far from equivalent to the instantaneous energy-level radiation relative to the plasma lifetime. For in-situ or portable applications, due to the high cost of ICCD, line or area CCD detectors with an integration time covering the entire plasma evolution process are mostly used in LIBS devices. Therefore, the uncertainty of the decay rate of the energy-level radiation during the integration stage cannot be ignored. As can be seen from the above formula, formula (5) is transformed into formula (6).

[0067] (6) This application uses a fixed time, optimizes the rules between different elements, and calibrates the matrix effect, as Figure 5 shown, where tm is the end time of exposure and tn is the start time of exposure.

[0068] Based on the experimental data of different delay times and integration windows, this application optimizes the acquisition parameters of the spectrometer 5 to reduce the matrix effect during the plasma evolution process. A reasonable time-resolved strategy can not only effectively reduce the self-absorption effect and background interference, but also improve the stability and accuracy of elemental quantitative analysis.

[0069] In an exemplary embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory. When the processor executes the computer program, the steps in the above method embodiments are implemented. The computer device can be a server or a terminal, and its internal structure diagram can be as Figure 6 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data to be processed. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with external terminals through a network connection. When the computer program is executed by the processor, a sample composition analysis method is implemented.

[0070] Those skilled in the art can understand, Figure 6The structure shown is only a block diagram of some structures related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine some components, or have different component arrangements. In an exemplary embodiment, a computer device is provided, including a memory and a processor. A computer program is stored in the memory, and when the processor executes the computer program, the steps in the above method embodiments are implemented.

[0071] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0072] In an exemplary embodiment, a computer program product is provided, including a computer program, and when the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0073] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data that have been authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0074] Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above methods. Among them, any reference to a memory, database, or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memories. Non-volatile memories can include read-only memory (ROM), magnetic tapes, floppy disks, flash memories, optical memories, high-density embedded non-volatile memories, resistive random access memories (ReRAM), magnetoresistive random access memories (MRAM), ferroelectric random access memories (FRAM), phase change memories (PCM), graphene memories, etc. Volatile memories can include random access memory (RAM) or external cache memories, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0075] The databases involved in the embodiments provided in the present application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., without limitation. The processors involved in the embodiments provided in the present application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logics, data processing logics based on quantum computing, etc., without limitation.

[0076] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered to be within the scope described in this specification.

[0077] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The descriptions of the above embodiments are only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A time-resolved LIBS system, characterized in that, Comprising: A laser generator for emitting ablation laser towards a sample on a sample stage; After the sample is irradiated by the ablation laser, a plasma is generated; During the expansion and cooling of the plasma, excited atoms and ions undergo energy level transitions, releasing characteristic radiation spectra; A delay control module, connected to the laser generator and the spectrometer, for setting different delay times to control the working time interval between the laser generator and the spectrometer; the working time interval is determined based on different elements; A spectrometer for receiving the characteristic radiation spectra at different delay times using an optical fiber probe and stimulating the characteristic radiation spectra under an integration time to determine the characteristic radiation spectral lines of different elements; A computer, connected to the spectrometer, for analyzing the characteristic radiation spectral lines, determining the spectral line intensities of different elements, and combining a calibrated spectral line intensity and an element content function curve to determine the composition result of the sample; the spectral line intensity is the integrated intensity.

2. The time-resolved LIBS system according to claim 1, wherein Further comprising: A reflector having an angle with the laser generator for changing the emission direction of the ablation laser.

3. The time-resolved LIBS system according to claim 2, characterized in that, Further comprising: A convex lens, parallel to the reflector and located on the reflection light path of the reflector, for focusing the ablation laser and irradiating the focused ablation laser onto the sample.

4. The time-resolved LIBS system according to claim 1, wherein, The working time interval is the time interval between the laser emission time of the laser generator and the light collection time of the spectrometer.

5. The time-resolved LIBS system according to claim 1, characterized in that, The plasma includes electrons, ions, atoms, and molecular fragments; At any moment, an atom or ion of the element makes a transition from a high energy level u level to a low energy level l level, and the integrated intensity generated by integrating the energy level radiation within the integration time is: ； Among them, is the delay time under the integral intensity; is t the instantaneous radiation intensity at the moment.

6. A method for analyzing the composition of a sample, characterized in that, The sample composition analysis method is applied to the time-resolved LIBS system according to any one of claims 1-5, and the sample composition analysis method includes: Instructing the delay control module to set different delay times to control the working time interval between the laser generator and the spectrometer; Receiving the characteristic radiation spectral lines of different elements transmitted by the spectrometer; the characteristic radiation spectral lines are determined by stimulating the characteristic radiation spectra at different delay times under an integration time; Analyzing the characteristic radiation spectral lines, determining the spectral line intensities of different elements, and combining a calibrated spectral line intensity and an element content function curve to determine the composition result of the sample; the spectral line intensity is the integrated intensity.

7. The sample composition analysis method according to claim 6, wherein At any moment, the atoms or ions of the element transition from a high energy level u level to a low energy level l level, and the integrated intensity generated by integrating the energy level radiation within the integration time is as follows: ； Among them, is the integration intensity at the delay time ; is t the instantaneous radiation intensity at the moment 8. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements the sample composition analysis method according to any one of claims 6-7.

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