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Laser-induced breakdown spectroscopy with improved detection sensitivity
Laser-induced breakdown spectroscopy (LIBS), as a powerful spectroscopic technology for chemical analysis with advantages of little or no sample preparation, in-situ and rapid analysis, simultaneously active for all elements, and remote detection capability, has been extensively applied in different fields in the past decades. However, higher detection sensitivity, special environmental applications, and compact LIBS system which can be used for field detection or integrated with other facilities for process monitoring are always desired. Therefore, the research in this dissertation includes 1) the study of LIBS in a high-temperature environment, 2) a proposed method for detection sensitivity improvement, 3) using compact double-pulse laser for LIBS detection with improved sensitivity, 4) using LIBS system for uranium and samarium detection in zircon glasses, and 5) 3D chemical mapping to determine spatial distribution of targeted elements. Specifically, (a) the plasma emission dynamics in a high-temperature flame environment was investigated. Enhanced optical signals were observed for plasma in high-temperature environment. (b) A compact commercial micro torch was used as a convenient and cost-effective method for LIBS detection sensitivity improvement. Especially, this method was demonstrated for optical signal enhancement at lower laser pulse energies, indicating great capability for sensitivity improvement of LIBS system with low power laser source. (c) A developed compact collinear double-pulse laser source was used for LIBS measurement. Optical signals with the enhancement factor more than 60 times were achieved and early spectra before 1 µs in double-pulse LIBS were studied. (d) The detection of uranium and samarium in zircon glasses reached a limit of detection (LOD) of 154 parts per million (ppm) for uranium and 6 ppm for samarium, respectively, using a standard LIBS system with appropriate gating time. (e) Three-dimensional (3D) LIBS mapping system was developed and used for determination of the spatial distribution of elements.
Physical chemistry|Electrical engineering
Liu, Lei, "Laser-induced breakdown spectroscopy with improved detection sensitivity" (2016). ETD collection for University of Nebraska-Lincoln. AAI10248738.