Spectrum detection method and system for plasma generated by laser ablation

Abstract

The invention belongs to the technical field of laser ablation and plasma spectrum detection, and discloses a method and a system for detecting a plasma spectrum generated by laser ablation. The plasma spectrum detection method comprises the following steps: acquiring a plasma spectrum signal; randomly generating N plasma temperatures based on the plasma spectral signal, wherein N is the population number of the plasma temperatures; taking the N plasma temperatures as parents, executing crossover operation according to a preset crossover probability, executing variation adjustment on the individuals after the crossover operation according to a preset variation probability to obtain variation offspring, replacing the individuals in the original parents with the variation offspring, continuously iterating and updating the population until an iteration termination condition is met, and terminating iteration to obtain a new population; the iteration termination condition is met, and the plasma temperature value corresponding to the minimum fitness function value is the final plasma temperature value. According to the invention, the accuracy and reliability of spectrum detection of plasma temperature can be obviously improved, and the detection requirements of complex matrix samples can be better met.

Description

Technical Field

[0001] The present invention relates to the technical field of laser ablation and plasma spectrum detection, and in particular to a plasma spectrum detection method and system generated by laser ablation. Background Art

[0002] With the development of laser ablation technology and plasma spectrum detection technology, these two technologies have been widely used in many fields, especially in material composition analysis and material damage detection.

[0003] The existing technology provides a spectral detection method. The sample to be tested is placed in a graphite heating device. An electric current is used to generate high temperatures to particle the sample to be tested. The particleized sample gas is then sprayed into a sample chamber. A femtosecond pulsed laser is then focused into a plasma for excitation, generating a plasma fluorescence spectrum that is detected by a spectral collection and detection module. This method has the following problems: First, it is complex and expensive. This method requires the use of a graphite heating device and a femtosecond laser. These complex and expensive equipment limits its widespread application in certain situations. Second, it is difficult to meet the needs of rapid detection. Since the sample must first be particle-ized, this increases the number of steps and time required, making it unsuitable for scenarios requiring rapid detection.

[0004] The prior art also provides a two-dimensional plasma lattice grating enhanced laser-induced breakdown spectroscopy detection sensitivity device, which forms light filaments and cross-interacts through beam splitting, time-domain synchronization and focusing to form a two-dimensional plasma lattice grating, thereby achieving sample excitation and collecting analysis spectra. This solution has the following shortcomings: First, the system complexity is high. The device requires multiple modules (such as beam splitting module, time-domain synchronization module, focusing module, etc.) to work together, the system is complex, and maintenance and debugging are difficult; second, the operation is difficult. Users need to have high professional skills and experience to correctly operate and maintain the device, and it is not suitable for application in ordinary laboratories or industrial sites; third, the scope of application is limited. It is mainly suitable for samples that are difficult to excite. The detection effect on conventional samples is not described in detail, and it is not suitable for all types of samples.

[0005] In summary, existing spectral detection methods and devices have shortcomings such as high complexity and cost, complex sample processing, low detection accuracy and efficiency, difficult operation, and limited scope of application. Summary of the Invention

[0006] The purpose of the present invention is to address the deficiencies of the existing technology and provide a method and system for detecting plasma spectra produced by laser ablation. The method randomly generates plasma temperature from the collected plasma spectrum signal, and iteratively optimizes the plasma temperature value through crossover and mutation operations, thereby significantly improving the accuracy and reliability of spectral detection of plasma temperature and better meeting the detection needs of complex matrix samples.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for detecting a plasma spectrum generated by laser ablation, comprising the following steps:

[0009] S1. Collect plasma spectrum signals;

[0010] S2. Randomly generate N plasma temperatures based on the plasma spectrum signal, where N is the number of plasma temperature populations;

[0011] S3. Take N plasma temperatures as parents, perform crossover operation according to the preset crossover probability, perform mutation adjustment on the individuals after the crossover operation according to the preset mutation probability to obtain mutant offspring, replace the individuals in the original parent generation with the mutant offspring, and continuously iterate and update the population until the iteration termination condition is met, then terminate the iteration. The plasma temperature value that meets the iteration termination condition and minimizes the fitness function value is the final plasma temperature value.

[0012] As a possible implementation, the plasma temperature is denoted as T j , j = 1, 2...N, and N plasma temperatures are randomly generated by the following method:

[0013] T j =T min +rand(0,1)×(T max ―T min )

[0014] Among them, T max is the maximum plasma temperature, T min is the minimum plasma temperature, and rand(0,1) is a random number distributed in [0, 1].

[0015] As a possible implementation, the preset crossover probability is 0.8 to 0.9; the preset mutation probability is 0.1 to 0.3.

[0016] As a possible implementation method, the iteration termination condition is: the fitness function value is less than or equal to 10 ―2 , or, the number of iterations is equal to 1000 times.

[0017] As a possible implementation, the fitness function is f(T j ):

[0018]

[0019] Where M is the number of selected wavelengths, i = 1 to M, I exp (λ i ) is the spectral intensity obtained by experimental measurement, I model (λ i ,T j ) is the spectral intensity predicted by the thermal radiation model, and the thermal radiation model is Among them, λ i is the i-th wavelength, h is Planck's constant, c is the speed of light, k B is the Boltzmann constant.

[0020] As a possible implementation method, the crossover operation includes: randomly selecting n1 plasma temperatures from N plasma temperatures based on a preset crossover probability to form a crossover population, n1<N; using a crossover model to perform a crossover operation on any two plasma temperatures in the crossover population, any two plasma temperatures before the crossover operation are recorded as Ta and Tb, and any two plasma temperatures after the crossover operation are recorded as Ta′ and Tb′, and the crossover model is: Ta′=(1―α)Ta+αTb, Tb′=αTa+(1―α)Tb, where α is a weight coefficient, and its value is [0, 1].

[0021] As a possible implementation method, the mutation operation includes: randomly selecting n2 plasma temperatures from the new crossover population formed after the crossover operation is performed based on a preset mutation probability to form a mutation population, where n2<n1; the plasma temperature before mutation is recorded as Tk′, Tk′ is Ta′ or Tb′, and the plasma temperature after mutation is recorded as Tk″, and the mutation model is: Tk″=Tk′+ε·ρ, where ε is a number randomly drawn from the standard normal distribution N(0,1), and ρ=k·(T max ―T min ), k is the proportional coefficient, the value is 0.05, if Tk′>T max , then let Tk′=T max .

[0022] In a second aspect, the present invention provides a plasma spectrum detection system generated by laser ablation, comprising:

[0023] a laser ablation module for generating a focused laser beam;

[0024] The sample processing module is used to fix the sample to be tested and focus the laser beam onto the sample to be tested to generate a plasma spectrum signal;

[0025] Spectral detection module, used to capture plasma spectrum signals;

[0026] The data processing module is used to execute S2 to S3 of the first aspect.

[0027] As a possible implementation method, the laser ablation module includes a pulsed laser and a laser focusing device; the pulsed laser is a nanosecond pulse width multi-pulse laser or a picosecond pulse width multi-pulse laser; the output single pulse energy and output pulse number of the pulsed laser are adjustable; the laser beam emitted by the pulsed laser is focused onto the surface of the sample to be tested by the laser focusing device, generating a plasma spectrum signal.

[0028] As a possible implementation, the data processing module includes a data acquisition card and a data processing unit. The data acquisition card receives the plasma spectrum signal captured by the spectrum detection module and transmits it to the data processing unit; the data processing unit executes S2 to S3 of the first aspect.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The plasma spectral detection method produced by laser ablation proposed in this invention randomly generates plasma temperature from the collected plasma spectral signal, and iteratively optimizes the plasma temperature value through crossover and mutation operations, thereby improving the accuracy and reliability of spectral detection of plasma temperature and better meeting the detection needs of complex matrix samples.

[0031] 2. The plasma spectrum detection method and system proposed in the present invention, which generate by laser ablation, do not require complicated sample processing, and are simple to operate, highly convenient and low in cost.

[0032] 3. The plasma spectrum detection system generated by laser ablation proposed in the present invention can automatically adjust the laser focus position when the position of the sample surface changes, ensuring that the laser is always focused on the optimal position on the sample surface, significantly improving the accuracy and consistency of laser ablation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 This is a flow chart of a method for detecting plasma spectra generated by laser ablation according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] To facilitate a clear description of the technical solutions of the embodiments of the present invention, the words "first" and "second" are used in the embodiments of the present invention to distinguish between identical or similar items with substantially the same functions and effects. For example, the first threshold and the second threshold are merely used to distinguish between different thresholds and do not limit their order. Those skilled in the art will understand that the words "first" and "second" do not limit the quantity or execution order, and the words "first" and "second" do not necessarily mean different.

[0036] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0037] In the present invention, "at least one" refers to one or more, and "more" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: the existence of A alone, the existence of A and B at the same time, and the existence of B alone, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. The following at least one item (item) or similar expressions thereof refer to any combination of these items, including any combination of single items (items) or plural items (items). For example, at least one item (item) of a, b or c can represent: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or multiple.

[0038] The embodiments of the present invention aim to provide a method and system for detecting plasma spectra generated by laser ablation, so as to solve the problems existing in the prior art, such as high complexity and high cost, complex sample processing, low detection accuracy and efficiency, great difficulty in operation, and limited scope of application.

[0039] In the first aspect, the present invention provides a method for detecting plasma spectra generated by laser ablation, see Figure 1 , including the following steps:

[0040] S1. Collect plasma spectrum signals;

[0041] As an example, a laser is focused onto the surface of a sample to be tested to generate a plasma spectrum signal, and a spectrum collection device is used to collect the generated plasma spectrum signal. At the same time, a fiber optic spectrometer is used to obtain a corresponding relationship curve between the wavelength and intensity of the spectrum signal in the plasma spectrum signal.

[0042] S2. Randomly generate N plasma temperatures based on the plasma spectrum signal, where N is the number of plasma temperature populations;

[0043] As a possible implementation, the plasma temperature is denoted as T j , j = 1, 2...N, and N plasma temperatures are randomly generated by the following method:

[0044] T j =T min +rand(0,1)×(T max ―T min )

[0045] Among them, T max is the maximum plasma temperature, T min is the minimum plasma temperature. As an example, the maximum plasma temperature T max =10 6 K, minimum plasma temperature T min =10 3 K.

[0046] rand(0,1) is a random number distributed in [0,1]. For example, the population number N of plasma temperature is 100, and 100 numbers are randomly generated between [0,1]. Since the maximum and minimum values ​​of the plasma temperature are known, N randomly generated plasma temperatures can be obtained based on the random value of rand(0,1).

[0047] S3. Taking N plasma temperatures as parents, performing a crossover operation according to a preset crossover probability;

[0048] As a possible implementation method, the preset crossover probability is 0.8-0.9; the crossover operation includes: randomly selecting n1 plasma temperatures from N plasma temperatures based on the preset crossover probability to form a crossover population, n1<N; for example, setting the crossover probability to 0.8 means that 80% of the parents participate in the crossover, that is, the number of plasma temperatures constituting the crossover population n1=N×80%.

[0049] A crossover model is used to perform a crossover operation on any two plasma temperatures in the crossover population. Before the crossover operation, any two plasma temperatures are recorded as Ta and Tb, and after the crossover operation, any two plasma temperatures are recorded as Ta′ and Tb′. The crossover model is: Ta′=(1-α)Ta+αTb, Tb′=αTa+(1-α)Tb, where α is the weight coefficient and its value is [0, 1].

[0050] The individuals after the crossover operation are then subjected to mutation adjustment according to the preset mutation probability to obtain mutant offspring;

[0051] As a possible implementation method, the preset mutation probability is 0.1 to 0.3; the mutation operation includes: randomly selecting n2 plasma temperatures from the new crossover population formed after the crossover operation is performed based on the preset mutation probability to form a mutation population, n2 < n1; the plasma temperature before mutation is recorded as Tk′, Tk′ is Ta′ or Tb′, and the plasma temperature after mutation is recorded as Tk″, and the mutation model is: Tk″=Tk′+ε·ρ, where ε is a number randomly drawn from the standard normal distribution N(0,1), and ρ=k·(T max ―T min ), k is the proportional coefficient, the value is 0.05, if Tk′>T max , then let Tk′=T max .

[0052] As an example, setting the mutation probability to 0.1 means that 10% of the offspring mutate, that is, the number n2 of plasma temperatures constituting the mutant population is 10% of the number of plasma temperatures in the new crossover population formed after the crossover operation is performed.

[0053] The individuals in the original parent generation are replaced by the mutated offspring, and the population is continuously updated iteratively until the iteration termination condition is met. The iteration is terminated, and the plasma temperature value corresponding to the minimum value of the fitness function and the satisfaction of the iteration termination condition is the final plasma temperature value.

[0054] As a possible implementation method, the iteration termination condition is: the fitness function value is less than or equal to 10 ―2 , or, the number of iterations is equal to 1000 times.

[0055] As a possible implementation, the fitness function is f(T j ):

[0056]

[0057] Where M is the number of selected wavelengths, i = 1 to M, I exp (λ i ) is the spectral intensity obtained by experimental measurement, I model (λ i ,T j ) is the spectral intensity predicted by the thermal radiation model, and the thermal radiation model is Among them, λ i is the i-th wavelength, h is Planck's constant, c is the speed of light, k B is the Boltzmann constant.

[0058] Fitness function f(T j ) is the sum of squares of the errors between the experimentally measured spectral intensity and the spectral intensity predicted by the thermal radiation model, and the fitness function f(Tj ) is smaller, indicating that the spectral intensity obtained by the experimental measurement is closer to the spectral intensity predicted by the thermal radiation model, so the plasma temperature value T at this time is j as the final plasma temperature value.

[0059] As an example, if the number of iterations has not reached 1000, the fitness function f(T j ) is less than or equal to 10 ―2 The temperature value is the final plasma temperature value. If the iteration reaches 1000 times, the fitness function f(T j ) is still not less than or equal to 10 ―2 , also terminate the iteration, and find the fitness function f(T j ) is taken as the final plasma temperature value.

[0060] This embodiment randomly generates plasma temperature from the collected plasma spectral signal, and iteratively optimizes the plasma temperature value through crossover and mutation operations, thereby improving the accuracy and reliability of spectral detection of plasma temperature and being able to better meet the detection needs of complex matrix samples.

[0061] In a second aspect, an embodiment of the present invention provides a plasma spectrum detection system generated by laser ablation, comprising: a laser ablation module, a sample processing module, a spectrum detection module, and a data processing module;

[0062] As a possible implementation, a control system is used to control the operation of the plasma spectrum detection system provided in this embodiment. Specifically, the control system includes a central processing unit, a data storage device, a signal transceiver, and a power management module.

[0063] As an example, the control system also includes a user interface and a remote control module. The user interface includes a touch screen and operating buttons, and the remote control module includes a remote communication module and a data transmission interface. The user interface is installed in front of the control system and is used to provide a user interface and display system status. The remote control module connects to external control devices via the data transmission interface and enables remote control via the remote communication module. The user interface provides a user interface via a touch screen and operating buttons. The central processing unit is connected to the user interface via a data bus, receives user commands and displays system status. The remote communication module connects to external control devices via the data transmission interface to enable remote data transmission and control.

[0064] The laser ablation module is used to generate a focused laser beam. As a possible implementation method, the laser ablation module includes a pulsed laser and a laser focusing device. The pulsed laser is a nanosecond pulse width multi-pulse laser or a picosecond pulse width multi-pulse laser. The output single pulse energy and output pulse number of the pulsed laser are adjustable. The laser beam emitted by the pulsed laser is focused onto the surface of the sample to be tested by the laser focusing device to generate a plasma spectrum signal.

[0065] As a possible implementation, the laser ablation module also includes an autofocus system, which includes an autofocus motor, a focus sensor, and a focus adjustment mechanism. The autofocus motor is mounted on the base of the laser focusing device and uses the focus sensor to monitor changes in the laser focus position in real time. The central processing unit sends instructions to the autofocus motor via a signal transceiver based on the spectral signal collected by the spectral collection device to adjust the laser focus position and ensure that the laser is focused on the optimal position on the sample surface. The focus adjustment mechanism includes multiple focusing lenses, each of which is connected to the main body of the laser focusing device via an adjustable connector. The autofocus motor drives the adjustment of the focusing lens through a linkage mechanism, allowing the focusing lens to automatically adjust the focus position according to the position of the sample surface.

[0066] The present invention can automatically adjust the laser focus position when the position of the sample surface changes, ensuring that the laser is always focused on the optimal position of the sample surface, thereby significantly improving the accuracy and consistency of laser ablation.

[0067] The sample processing module is used to fix the sample to be tested and irradiate the focused laser beam onto the sample to be tested to generate a plasma spectrum signal;

[0068] As an example, a sample stage is installed below the laser focusing device to fix the sample to be tested. The sample fixing device includes a sample stage bracket and a sample fixing clamp. The sample stage bracket is installed below the sample stage to support the sample stage. The sample fixing clamp is installed on the sample stage to fix the sample to be tested and ensure that the sample is in a stable position during the laser ablation process.

[0069] The spectrum detection module is used to capture plasma spectrum signals;

[0070] As a possible implementation method, the spectral detection module includes a spectrometer and a spectral collection device. The spectral collection device includes a spectral collection optical fiber, a spectral collection lens and a spectral collection probe. The spectral collection optical fiber is connected to the spectral collection probe through the spectral collection lens. The spectral collection probe is installed on the side of the laser focusing device to capture the plasma spectral signal.

[0071] As an example, the spectral detection module also includes a multi-wavelength spectral analysis system, which includes a multi-wavelength filter and a spectral analysis unit. The multi-wavelength filter is installed between the spectral collection probe and the spectral collection lens to selectively filter spectral signals of different wavelengths. The spectral analysis unit is connected to the central processing unit to analyze the spectral signals of different wavelengths and extract spectral peak characteristics. The multi-wavelength filter has a wavelength range of 200 to 1000 nm. By extracting spectral peak characteristics, the accuracy and reliability of spectral detection of plasma temperature are improved.

[0072] The data processing module is used to execute S2 to S3 of the first aspect.

[0073] As a possible implementation, the data processing module includes a data acquisition card and a data processing unit. The data acquisition card receives the plasma spectrum signal captured by the spectrum detection module and transmits it to the data processing unit. The data processing unit performs S2 to S3 of the first aspect, namely:

[0074] Based on the plasma spectrum signal, N plasma temperatures are randomly generated, where N is the population number of plasma temperatures. Specifically, the plasma temperature is recorded as T j , j = 1, 2...N, and N plasma temperatures are randomly generated by the following method:

[0075] T j =T min +rand(0,1)×(T max ―T min )

[0076] Among them, T max is the maximum plasma temperature, T min is the minimum value of plasma temperature, rand(0,1) is a random number uniformly distributed in [0,1]. For example, the population number N of plasma temperature is 100, and the maximum value of plasma temperature T max =10 6 K, minimum plasma temperature T min =10 3 K.

[0077] Take N plasma temperatures as parents, perform crossover operation according to the preset crossover probability, perform mutation adjustment on the individuals after the crossover operation according to the preset mutation probability to obtain mutant offspring, replace the individuals in the original parent generation with the mutant offspring, and continuously iterate and update the population until the iteration termination condition is met. Then terminate the iteration. The plasma temperature value that meets the iteration termination condition and minimizes the fitness function value is the final plasma temperature value.

[0078] In specific implementations, the crossover probability is preset to 0.8-0.9. The crossover operation includes randomly selecting n1 plasma temperatures from N plasma temperatures based on the preset crossover probability to form a crossover population, where n1 < N. For example, setting the crossover probability to 0.8 means that 80% of the parents participate in the crossover, that is, the number of plasma temperatures forming the crossover population, n1 = N × 80%. A crossover operation is performed on any two plasma temperatures in the crossover population using a crossover model. Before the crossover operation, any two plasma temperatures are denoted as Ta and Tb, and after the crossover operation, any two plasma temperatures are denoted as Ta' and Tb'. The crossover model is: Ta' = (1-α)Ta + αTb, Tb' = αTa + (1-α)Tb, where α is a weight coefficient and takes a value in the range [0, 1].

[0079] The preset mutation probability is 0.1 to 0.3; the mutation operation includes: randomly selecting n2 plasma temperatures from the new crossover population formed after the crossover operation is performed based on the preset mutation probability to form a mutation population, where n2 < n1; the plasma temperature before mutation is recorded as Tk′, Tk′ is Ta′ or Tb′, and the plasma temperature after mutation is recorded as Tk″, and the mutation model is: Tk″=Tk′+ε·ρ, where ε is a number randomly drawn from the standard normal distribution N(0,1), and ρ=k·(T max ―T min ), k is the proportional coefficient, the value is 0.05, if Tk′>T max , then let Tk′=T max For example, if the mutation probability is set to 0.1, it means that 10% of the offspring mutate, that is, the number of plasma temperatures n2 constituting the mutant population is 10% of the number of plasma temperatures in the new crossover population formed after the crossover operation is performed.

[0080] The iteration termination condition is: the fitness function value is less than or equal to 10 ―2 , or, the number of iterations is equal to 1000 times, and the fitness function is f(T j ), Where M is the number of selected wavelengths, i = 1 to M, I exp (λ i ) is the spectral intensity obtained by experimental measurement, I model (λ i ,T j ) is the spectral intensity predicted by the thermal radiation model, and the thermal radiation model is Among them, λ i is the i-th wavelength, h is Planck's constant, c is the speed of light, k B is the Boltzmann constant.

[0081] As an example, a data acquisition card is connected to a spectrometer to collect spectral signals output by the spectrometer. A data processing unit is connected to the data acquisition card to process the collected spectral signals, extract spectral features, and store the processed data in a data memory. The data processing unit is connected to a central processing unit, which is connected to the data memory via a data bus to store data collected by the spectral detection module and data processed by the data processing unit.

[0082] As a possible implementation method, the laser ablation module is connected to the spectrum detection module through a spectrum collection device, and is connected to the control system through a signal transceiver. The spectrum detection module is connected to the data processing module through a data acquisition card, and is connected to the control system through a data bus. The sample processing module is connected to the laser ablation module through a sample tray, and is connected to the control system through a signal transceiver.

[0083] The plasma spectrum detection method and system proposed in the present invention, which generate by laser ablation, do not require complicated sample processing, and are simple to operate, highly convenient and low in cost.

[0084] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art can understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the accompanying drawings. In the specification, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit can implement several functions listed in the specification. Certain measures are recorded in different embodiments, but this does not mean that these measures cannot be combined to produce good results.

[0085] Although the present invention has been described with reference to specific features and embodiments thereof, it will be apparent that various modifications and combinations thereof may be made without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the present invention and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the invention. It will be apparent that various modifications and variations of the present invention may be made by those skilled in the art without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such modifications and variations as fall within the scope of the invention and its equivalents.

Claims

1. A method for detecting plasma spectra generated by laser ablation, characterized in that: The steps include: S1. Collect plasma spectrum signals; S2. Randomly generate N plasma temperatures based on the plasma spectrum signal, where N is the number of plasma temperature populations; S3. Take N plasma temperatures as parents, perform a crossover operation according to a preset crossover probability, perform mutation adjustment on the individuals after the crossover operation according to a preset mutation probability to obtain mutant offspring, and replace the individuals in the original parent generation with the mutant offspring. Continuously iterate and update the population until the iteration termination condition is met, then terminate the iteration. The plasma temperature value corresponding to the minimum fitness function value that satisfies the iteration termination condition is the final plasma temperature value; Among them, the crossover operation includes: randomly selecting n1 plasma temperatures from N plasma temperatures based on a preset crossover probability to form a crossover population, n1<N; using a crossover model to perform a crossover operation on any two plasma temperatures in the crossover population, any two plasma temperatures before the crossover operation are recorded as Ta and Tb, and any two plasma temperatures after the crossover operation are recorded as Ta′ and Tb′, and the crossover model is: Ta′=(1―α)Ta+αTb, Tb′=αTa+(1―α)Tb, where α is a weight coefficient, and its value is [0, 1].

2. The method for detecting plasma spectrum generated by laser ablation according to claim 1, characterized in that: The plasma temperature is denoted as T j , j = 1, 2...N, and N plasma temperatures are randomly generated by the following method: T j =T min +rand(0,1)×(T max ―T min ) Among them, T max is the maximum plasma temperature, T min is the minimum plasma temperature, and rand(0,1) is a random number distributed in [0, 1].

3. The method for detecting plasma spectrum generated by laser ablation according to claim 1, characterized in that: The preset crossover probability is 0.8-0.9; the preset mutation probability is 0.1-0.

3.

4. The method for detecting plasma spectrum generated by laser ablation according to claim 2, characterized in that: The iteration termination condition is: the fitness function value is less than or equal to 10 ―2 , or, the number of iterations is equal to 1000 times.

5. The method for detecting plasma spectrum generated by laser ablation according to claim 4, characterized in that: The fitness function is Where M is the number of selected wavelengths, i = 1 to M, I exp (λ i ) is the spectral intensity obtained by experimental measurement, I model (λ i ,T j ) is the spectral intensity predicted by the thermal radiation model, and the thermal radiation model is Among them, λ i is the i-th wavelength, h is Planck's constant, c is the speed of light, k B is the Boltzmann constant.

6. The method for detecting plasma spectrum generated by laser ablation according to claim 1, characterized in that: The mutation operation includes: randomly selecting n2 plasma temperatures from the new crossover population formed after the crossover operation is performed based on the preset mutation probability to form a mutation population, where n2<n1; the plasma temperature before mutation is recorded as Tk′, Tk′ is Ta′ or Tb′, and the plasma temperature after mutation is recorded as Tk″. The mutation model is: Tk″=Tk′+ε·ρ, where ε is a number randomly drawn from the standard normal distribution N(0,1), and ρ=k·(T max ―T min ), k is the proportional coefficient, the value is 0.05, if Tk′>T max , then let Tk′=T max .

7. A plasma spectrum detection system generated by laser ablation, characterized in that: include: a laser ablation module for generating a focused laser beam; The sample processing module is used to fix the sample to be tested and focus the laser beam onto the sample to be tested to generate a plasma spectrum signal; Spectral detection module, used to capture plasma spectrum signals; A data processing module is used to execute S2 to S3 described in claim 1.

8. The plasma spectrum detection system generated by laser ablation according to claim 7, characterized in that: The laser ablation module includes a pulse laser and a laser focusing device; the pulse laser is a nanosecond pulse width multi-pulse laser or a picosecond pulse width multi-pulse laser; the output single pulse energy and output pulse number of the pulse laser are adjustable; The laser beam emitted by the pulsed laser is focused onto the surface of the sample to be tested by a laser focusing device to generate a plasma spectrum signal.

9. The plasma spectrum detection system generated by laser ablation according to claim 8, characterized in that: The data processing module includes a data acquisition card and a data processing unit. The data acquisition card receives the plasma spectrum signal captured by the spectrum detection module and transmits it to the data processing unit; the data processing unit executes S2 to S3 described in claim 1.

10. The plasma spectrum detection system generated by laser ablation according to claim 7, characterized in that: The spectrum detection module includes a spectrometer and a spectrum collection device. The spectrum collection device includes a spectrum collection optical fiber, a spectrum collection lens and a spectrum collection probe. The spectrum collection optical fiber is connected to the spectrum collection probe through the spectrum collection lens. The spectrum collection probe is installed on the side of the laser focusing device to capture the plasma spectrum signal.

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