Fabrication And Application Of Laser Induced Breakdown Spectroscopy

Laser induced breakdown spectroscopy (LIBS) is a relatively new elemental detection and analysis technique. It is achieved by focusing a short-pulse laser beam on a sample surface to vaporize a small amount of a sample and generate plasma that is rich in electrons, excited atoms and irons. The excited atoms and ions in the plasma emit radiation that is characteristic of the elemental composition of the sample. LIBS has the ability to detected all elements of solids, liquids, gases by analyzing the data of spectroscopy that is acquired by spectrometer. Excepting for characteristic peak what atoms emit, the spectroscopy contains the bremsstrahlung of charged particle, but the background spectroscopy coming from bremsstrahlung doesn't effect the identification of elements.In resent years, the interesting of studying laser induced breakdown spectroscopy is increasing in international and local day by day. The technique of LIBS is popularized from lab to environment monitoring, relic identification and protection, medical and medicine and numerous other fields. Because LIBS is affected easily by environmental factor and there is a long distance between LIBS and traditional analysis techniques in quantitative analysis, it needs more study for overall popularization.In this thesis, a brief introduction of influencing factor, research status and basic principle of laser induced breakdown spectroscopy was presented; the fundamental mechanical of LIBS was described; an experimental system was set up; a software using for acquisition and enquiry the data of spectroscopy was designed base on spectrometer HR4000; after that we studied laser induced breakdown spectroscopy of sample. In analyzing the spectroscopy of the sample of Al and Si, we found that some new characteristic peaks of AlⅢand SiⅢappeared in vacuum, because the temperature of plasmas in vacuum is higher than that in air due to the decreasing of the cooling time of plasmas. We researched the factors which will affect the LIBS signals, such as laser energy and frequency. The result showed that the augmenter of signal intensity of the spectroscopy of air is higher than that of the sample as the laser energy increasing; as the frequency of laser pulse increase, we would acquired good signal intensity of sample using low laser energy. We analyzed how to identify the characteristic peak and reduced the affect of wavelength deviation by spectroscopy translation and comparing to the spectroscopy of standard sample.