Gregg A. Lithgow

Laser-Induced Breakdown Spectroscopy Detection and Classification of Biological Aerosols

Laser-induced breakdown spectroscopy (LIBS) is examined as a potential method for detecting airborne biological agents. A spectrally broadband LIBS system was used for laboratory measurements on some common biological agent simulants. These measurements were compared to those of common, naturally occurring biological aerosol components (pollen and fungal spores) to determine the potential of LIBS for discriminating biological agents from natural background aerosols. A principal components analysis illustrates that linear combinations of the detected atomic lines, which are present in different ratios in each of the samples tested, can be used to discriminate biological agent simulants from other biological matter. A more sensitive, narrowband LIBS instrument was used to demonstrate the detection of single simulant (Bg) particles in the size range 1–5 μm. Ca, Mg, and Na, which are present in varying concentrations between 0.3 and 11% (by mass) in the Bg particles, were observed in single particles using LIBS.

LIBS in Industry: Sparks Fly

Laser-induced breakdown spectroscopy (LIBS) is emerging as a potent industrial spectroscopy. Uniquely capable for light-element detection, useful for material identiifcation, depth profiling, and elemental surface mapping, LIBS can solve numerous industrial problems in real-time.

Combustion system analysis using laser-induced breakdown spectroscopy

Practical combustion systems are characterized by rapid fluctuations due to turbulence and unsteady operation. Real-time diagnostic and analysis methods must be both highly sensitive and capable of capturing significant amounts of information instantly. This talk describes the use of Laser-Induced Breakdown Spectroscopy (LIBS) for combustion system analysis, including the measurement of complete mixture fraction, inorganic species concentrations, and/or associations of individual elements in aerosol particulate matter, in a single measurement. Equivalence ratio measurements in engines, parameterized by ratios of observed C, O, and N emission lines, have been used to determine fluctuations in operation and ascertain performance. In laboratory diffusion flames similar measurements have been used to determine PDFs of turbulent mixing between air and fuel. In addition, the composition of particulate matter may be monitored, both trace species and major species. These multiple measurement modalities make LIBS attractive as a general, broadband diagnostic for combustion systems. Future directions and new applications will be addressed.Practical combustion systems are characterized by rapid fluctuations due to turbulence and unsteady operation. Real-time diagnostic and analysis methods must be both highly sensitive and capable of capturing significant amounts of information instantly. This talk describes the use of Laser-Induced Breakdown Spectroscopy (LIBS) for combustion system analysis, including the measurement of complete mixture fraction, inorganic species concentrations, and/or associations of individual elements in aerosol particulate matter, in a single measurement. Equivalence ratio measurements in engines, parameterized by ratios of observed C, O, and N emission lines, have been used to determine fluctuations in operation and ascertain performance. In laboratory diffusion flames similar measurements have been used to determine PDFs of turbulent mixing between air and fuel. In addition, the composition of particulate matter may be monitored, both trace species and major species. These multiple measurement modalities make LIBS ...