Laser-Induced Breakdown Spectroscopy And Its Application In Gemmology

Laser-Induced Breakdown Spectroscopy - which we call it LIBS,is a new developed technology for chemical elements analyses.It has several important advantages such as no need to prepare samples,easy operation,and high sensitivity.So there have many researches on it and make a rapid development.The first used for LIBS to Gemmology is to identify the Be-diffused corundum,which is a kind of new diffuse method and is hard to identify by usual test.There are three method be found to identify the Be-diffused corundum,which are LA-ICP-MS,SIMS,and LIBS.Compare whit the former two technologies,LIBS has a simpler setup and lower price. Also,to identify Be-diffused corundum is not the only use of LIBS for Gemmology,but because of the late appearance there is no many research about this now.This article is mainly about the research of our LIBS system and its application to Gemmology.The first part of this article is summarizing the current research about LIBS,from the aspects of setup,analyses software,quantitative methods and the application.Also have some introductions about the application research for gemology.The second part is about our LIBS system.After explaining the fundamental theory of laser-induced breakdown spectroscopy,we mainly introduced our LIBS setup:the equipments and the abilities.There are some improvements for this system,such as the environment gas,the spectrum collection mode and so on.Also the stability research is done,and from the result we can found that laser is the main influence to the apparatus precision.The method to avoid this influence is putted up,which is taking the average of many tests at the same place.But this method would increase the damage and seemed not good for gemstone test.Detect limit of this LIBS system is also computed in this part.The third part of this thesis is the development of LIBS software.The development environment is visual C++ 6.0,and uses the Microsoft Access database.The software have three parts of functions,there are spectrum measure,spectrum analysis and the spectrum database.The first function is based on the DLL file,recurs all the measure fictions which the spectrometer's own software have.The second and the third functions are wrote and designed by ourselves. Spectrum analysis contains many functions,which are peak-seeking,baseline correction, auto-elements analyses,spectrum extending,and so on.Spectrum database allow user set up their sample spectrum database,and by the spectrum match function,user can identify the type of the sample quickly.We also set up ourselves gemstone database,which contains more than seventy spectrums of gemstones,minerals and noble metals.Also the spectrum analysis and the spectrum database function can be used to all the laser-induced breakdown spectroscopy.The fourth party uses the above LIBS system to quantitative analyze some gemstones and the gold alloy.There are three quantitative models be used,the traditional quantitative method, calibration free LIBS method and external standard normalization method.Compared the three method,we can find that the quantitative analysis for gold alloy can use the traditional quantitative method and for the rocks the external standard normalization method seemed can achieve a better accuracy than other two methods.The fifth part takes many practices to the LIBS use for Gemmology and concludes seven aspects of the potential use for Gemmology research.LIBS can be used to identify the Be-diffused corundum,identify the glue-filled jadeite,distinguish the sea water pearl and the fresh water pearl,measure the transition metal elements,identify the type of stones quickly, identify the origin of the gemstones and analysis the purity of the noble metal.Form above practices,we summarize some notice for the LIBS use to Gemmology.At the end of this article,we discuss and sum up the all researches above,and make a clearly and definitely goal for the further study.