Research Of Cr In Stainless Steel Alloy With Femtosecond Laser Induced Breakdown Spectroscopy

Femtosecond laser induced breakdown spectroscopy (FsLIBS) is a brand newtechnique for element analysis. It has advantage such as ultrafast time resolution andreal time analysis mode. For LIBS, the femotseond laser pulse is focused into thesurface of the sample, it may melt the materials rapidly and produce high-temperatureplasma, then we use detector to measure the emission spectra and analysis the samples.After the research for last ten years, many theories and experimental results arepublished, but laser induced plasma is very complex, it may be affected by the sampleor the experimental setup and so on. Compare to nanosecond laser pulse, femotsecondlaser pulse can achieve minimum the effect of force and heat, and exclude the effectof environmental materials. Benefitting the ultrafast and ultrahigh intensity offemtosecond laser pulse, FsLIBS has unique advantage for accurate manufacture,which has very important and extensive application.This thesis will include five parts. First, we started from describing the history ofthe femtosecond laser pulse and his character, second, we carefully introduced theprinciple of the FsLIBS, the methods for analysis the sample and calculating theelectron temperature are also discussed here. Third, we briefly described theinstrument and how to run the experiment, the fs laser pulse is used to ablation stealwith different density of Cr and induce plasma, the plasma spectroscopy will bemeasured by the detector. Forth, the data analysis and further discussions are shownhere, we found three separate Cr lines around427nm, those lines integral intensity iscalculated, and then we can revise the intensity basing on the relation between theplasma temperature and integral intensity. Finally we can discuss the dependencebetween integral intensity and the Cr density; the experimental results are testified by the origin simulation. The last part is summery, we conclude the motivation of ourresearch, which is that basing on the well known curve of typical sample, and we candirectly get the density ratio of the new sample. We also summarized the experienceof the experimental data analysis and show the perspective of our research.