Research And Application Of Stand-off Laser-Induced Breakdown Spectroscopy Assisted With Multi-collector

Laser-induced breakdown spectroscopy(LIBS)has the advantages of real-time and in situ detection,no complex sample pretreatment,and capable of remote or stand-off detection.However,the detection equipment for remote or stand-off detection is expensive and bulky,which is not convenient to carry.Moreover,the detection sensitivity and accuracy are very low for stand-off LIBS.Based on this,a multi-collector(MC)stand-off LIBS detection system based on artificial optical compound eye(AOCE)structure was presented in this thesis.Taking rock samples as targets,the MC stand-off LIBS system performance was investigated to find a high-performance,and portable stand-off LIBS detection method.The content is as follows:The MC stand-off LIBS detection system based on AOCE was presented for the first time.The comparison with traditional telescope collection system shows that the detection performances are also at the same level under the same effective collection area,and the MC stand-off LIBS detection system can offer a better analysis accuracy and sensitivity.The qualitative methods based on the MC stand-off LIBS system were studied.The performances of MC stand-off LIBS assisted with principal component analysis(PCA)and linear discriminant analysis(LDA)were compared when analyzing the rock powder samples.Furthermore,an automatic spectral peak identification LDA(ASPI-LDA)algorithm was applied for stand-off LIBS for the first time.The classification results show that ASPI-LDA can improve the efficiency and the accuracy of the qualitative detection effectively.The quantitative methods based on the MC stand-off LIBS system were also investigated.The conventional quantitative methods and partial least-squares regression(PLSR)algorithm were adopted for quantitative analysis of rock power samples.In addition,the elemental contents of marble samples were calculated by calibration-free LIBS(CF-LIBS),and the results meet the requirement of quantitative analysis without standard samples in remote distance.Finally,the concept analyzer based on multi-collector stand-off LIBS was design by solidworks software.In summary,the MC stand-off LIBS system was systemically investigated in this thesis,which has greatly improved the detection performances of stand-off LIBS,and this study may provide technical and theoretical support for wider application of LIBS for remote analysis.