A fundamental study of laser-induced breakdown spectroscopy using fiber optics for remote measurements of trace metals. 1998 annual progress report

Technical Report · Mon Jun 01 00:00:00 EDT 1998

DOI:https://doi.org/10.2172/13445· OSTI ID:13445

Goode, S; Angel, S M

'Improved technologies are required by DOE for characterization and monitoring for site clean-up and waste processing applications. Especially needed are field deployable methods and devices of real-time monitoring to reduce dependency on laboratory analyses which are costly and time consuming. Improved sensors are needed for on-site analyses to provide real-time analytical capabilities for screening level and/or decision-quality data. Matrices of interest to the DOE are soils (or other solids), slurries, and aqueous and non-aqueous solutions. Laser-induced breakdown spectroscopy (LIBS) is a useful method for determining the elemental composition of solids. This method has been recently reviewed and a number of different applications have been described. In the LIBS technique, a high-power pulsed laser is used to generate a plasma from the sample of interest. This phenomenon was first demonstrated in 1963 using a pulsed ruby laser. The elemental composition of the sample is accomplished by measuring the atomic emission from the atoms and ions in the plasma. There are many reports of the use of LIBS for measuring metals in solid substrates. There have also been LIBS investigations of aerosols, single particles, metals in solution including uranium, and even chlorinated species in solution. More recently, LIBS has been used for measuring Ba and Cr in soil using a fiber-optic cable. LIBS shows great potential for measuring metal contaminants in soils and on particles (e.g., stack emissions) based on their atomic emission in a laser-induced plasma. Another important application for this technique is the remote analysis of highly radioactive materials, such as the glasses produced by the Defense Waste Processing Facility. The use of fiber optics for both collection of the atomic emission and delivery of the laser to the sampling area could eliminate the need for sampling. In this work the authors study the time-evolution of the LIBS emission for different matrices to better understand how to optimize the signal. Also, they investigate the use of fiber optics for laser delivery and signal collection, and the influence of the geometry of the fiber optic launch and collection probes to determine the effect on the signal-to-noise ratio (SNR). Finally, they study the LIBS signal for different sample matrices as a function of excitation wavelength across a broad spectrum. A result of this study should be a determination of the optimal excitation and collection conditions and sampling times for metal contaminants in different matrices, and an understanding of the strengths and limitations of using fiber optics for LIBS sampling.'

• Research Organization: Univ. of South Carolina, Dept. of Chemistry and Biochemistry, Columbia, SC (US)
• Sponsoring Organization: USDOE Office of Environmental Management (EM), Office of Science and Risk Policy
• OSTI ID: 13445
• Report Number(s): EMSP-55205-98; ON: DE00013445
• Country of Publication: United States
• Language: English

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Progress Report
Laser Spectroscopy
Ablation
Remedial Action
Decontamination
Decommissioning
High-Level Radioactive Wastes
Radioactive Wastes
Chemical Wastes
PROGRESS REPORT
LASER SPECTROSCOPY
ABLATION
REMEDIAL ACTION
DECONTAMINATION
DECOMMISSIONING
HIGH-LEVEL RADIOACTIVE WASTES
RADIOACTIVE WASTES
CHEMICAL WASTES