Software Development And Application For Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy(LIBS)is a promising element analysing technology,owing to the unique features of fast analysis speed,simple sample preparation,remote and on-line analysis,etc.This technology has received more and more attentions in the fields of metallurgy,agriculture,geology,energy and environmental protection,and get great advance in hardware development and experimental technology in the last few years.The development of software system for LIBS has also been in great interest.However,the ability of cooperative devices control and comprehensive data analysis are mostly unavailable in those programs at the present moment.The lack of advanced software system for LIBS already has become the bottleneck affecting general adoption for LIBS instruments.Therefore,there is an urgent need to develop a comprehensive LIBS software system.Therefore,in this paper we present a software system,which has the ability of cooperative hardware control,qualitative and quantitative data analysing,and applied it on various LIBS equipment developed by our research group.The main research contents and results of this paper are listed below:(1)A modular software development framework has been implemented.This framework effectively solves a series of problems in the software system development process,such as a great number of hardware need to control,complex functions need to implement,demands were constantly changing,and so on.At the same time,by provides a secure runtime environment for each module,between modules and modules,modules and the whole system,the stability of the software improved significantly.What's more,by supporting modular development with high flexibility and efficiency,the implementation of this architecture lays the foundation for the development of laser probe software.(2)Based on the above framework,a comprehensive LIBS software has been implemented.By providing different modules and the combination of those modules with the different instrument's components/requests,like individual device control,cooperative devices control,and qualitative/quantitative data analysis.This software has been running well on five different LIBS equipment serials,and makes these instruments easier to use and improves the productivity.(3)A spectrometer wavelength calibration method for C-T spectrometer and a spectral reduction algorithm for Echelle spectrometer were proposed.These two types of spectrometer are the two most commonly used spectrometers in the field of LIBS,however,the conventional calibration procedure for C-T spectrometer is hard to carry-out,and the reduced spectral data accuracy with conventional algorithm for Echelle spectrometer is deteriorated easily with the ambient temperature changing and mechanical vibration.To solve these problems,a new calibration method for C-T spectrometer and spectral reduction algorithm for Echelle spectrometer are presented.The new calibration method for C-T spectrometer is easy to perform and improves spectral accuracy at both ends in the detector.Unlike conventional approaches,the new spectral reduction algorithm for the Echelle spectrometer is to model the spectrogram rather the spectrometer,which makes the algorithm more adaptive to different designs.This algorithm also introduces a dynamic adjusting procedure for generating optimized spectra from laser-induced plasmas.This additional step improved the spectrum stability and absolute line intensity of the spectrum and yielded better quantification performance.Experimental results demonstrated that the quantification results of analyzing elements of Si,Mn,Ni,Zn in aluminum alloy samples were generally improved,theR~2 factor improved 5.3%,3.3%,2%,2.8%respectively,the LoD factor improved 46%,77%,62%,46%respectively,the RMSECV factor improved 19%,66%,40%,43%respectively.(4)The spectral line recognition and background subtraction problems were studied.Aiming at the difficulty of element spectral line recognition in spectral data,an automated method for determining algorithm parameters is proposed on the basis of conventional ridge line peak finding algorithm,which achieves good spectral peak finding without human intervention.Aiming at the problem that the continuous background is difficult to deduct effectively in the spectral data,based on the background subtraction algorithm based on wavelet transform,an automatic parameter optimization algorithm based on the fitting degree of the spectral peak is proposed as the evaluation factor,which realizes the effective deduction of the continuous background of the spectrum.Reduce the fluctuation of the spectrum and improve the accuracy of the quantitative model.Experimental results demonstrated that the quantification results of analyzing elements of Mn,Cr,Ni,Co in iron alloy samples were generally improved,theR~2 factor improved 1.9%,1.1%,0.9%,4.6%respectively,the LoD factor improved 43%,58%,31%,55%respectively,the RMSECV factor improved 32%?54%?30%?17%respectively.(5)For the five different series of laser probe equipment developed by our research group,this software system has carried out a series of application verification in different applications and for different detection requirements.The laser probe device equipped with this software has been successfully used for quantitative analysis of elements in samples such as steel,titanium alloy,aluminum alloy,iron ore,elements distribution analysis in samples such as optical fiber preforms,metal ores,and soil sample pellets,and qualitative or semi-quantitative analysis of core,plastic,soil and other samples.In summary,this paper studies the development of software systems from software architecture,functional implementation,key equipment and data processing,and develops integrated control and analysis software with complete functions and good performance.The engineering practice laid the foundation for the software.The serialized laser probe component analysis equipment equipped with this software system has been successfully applied in the detection of steel,ore,special alloys,non-metal materials,etc.,laying the foundation for mass production of equipment.