Laser-Induced Breakdown Spectroscopy of Steels at Atmospheric Pressure and in Air

Belliveau, James F.; Cadwell, L.; Coleman, Kenneth; Hüwel, Lutz; Griffin, H.

doi:10.1366/0003702854250202

Cited by 30 publications

(4 citation statements)

References 5 publications

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“…The majority of the LIBS studies have involved solid samples (e.g., paper, soils, paint, metals, steel); LIBS analysis of gaseous samples have been reported for the detection of F, Cl, S, P, As, and Hg in air and column III, V hydrides (e.g., B 2 H 6 , PH 3 ). − The intent of the studies was the measurement of trace amounts of analytes in hostile environments and gas impurities for the hydride work. Hg was detected at the parts per billion level in air using a photodiode array detection system which recorded single-shot spectra over a range of 20 nm .…”

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confidence: 99%

Laser-Induced Breakdown Spectroscopy for Real-Time Detection of Halon Alternative Agents

et al. 1998

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We report the results of an evaluation of laser-induced breakdown spectroscopy (LIBS) for the detection of candidate halon replacement compounds (CF 4 , CF 3 H, CF 2 H 2 , C 2 F 5 H). The fundamental (1.064 µm) from a Nd: YAG Q-switched pulsed laser was focused into an air flow containing 0.0005-5% of the analyte halocarbon compounds. The laser-produced plasma emission consists of a large number of intense fluorine atom lines in the 600-850 nm spectral range. Limit-of-detection studies indicate that LIBS can detect these compounds in the parts per million range. Also, we have recorded singleshot LIBS spectra with good signal-to-noise ratios using an intensified photodiode array. Our results indicate that LIBS is a promising detection technique for in situ and real-time measurement of halons during use in full-scale fire suppression testing.

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confidence: 99%

Laser-Induced Breakdown Spectroscopy for Real-Time Detection of Halon Alternative Agents

et al. 1998

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“…No sample preparation is necessary for LIBS, making it a very popular technique in many applications that include environmental monitoring [10][11][12], material analysis [13], forensics [14], characterization of fossils [15], biological identification [16,12], analysis of works of art [17], and space exploration [18,19]. Though the applications of LIBS are vast, LIBS suffers a disadvantage in sensitivity when compared to other spectroscopy techniques, such as inductively coupled plasma atomic emission spectroscopy (ICP-AES) [20][21][22][23][24]. Double-pulse laser-induced breakdown spectroscopy (DP-LIBS) is typically used to improve sensitivity compared to single-pulse LIBS (SP-LIBS) [25].…”

Section: Introductionmentioning

confidence: 99%

Effect of atmosphere on collinear double-pulse laser-induced breakdown spectroscopy

Effenberger

Scott

2011

Anal Bioanal Chem

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Double-pulse laser-induced breakdown spectroscopy (DP-LIBS) has been shown to enhance LIBS spectra. Several researchers have reported significant increases in signal-to-noise (S/N) and/or spectral intensity compared to single-pulse (SP) LIBS. In addition to DP-LIBS, atmospheric conditions can also increase sensitivity. Thus, in this study, a collinear DP-LIBS scheme was used along with manipulation of the atmospheric conditions. The DP-LIBS scheme consisted of an initial 45 mJ pulse at 1064 nm fired into a sample contained in a controlled atmospheric/vacuum chamber. A second analytical 45 mJ pulse at 1064 nm was then fired 0 to 200 μs after and along the same path of the first pulse. Ar, He, and air at pressures ranging from atmospheric pressure to 1 Torr are introduced during DP-LIBS and SP-LIBS experiments. For a brass sample, significant increases in the spectral intensities of Cu and Zn lines were observed in DP-LIBS under Ar compared to DP-LIBS in air. It was also found that Cu and Zn lines acquired with SP-LIBS in Ar are nearly as intense as DP-LIBS in air. While collinear DP-LIBS is effective for increasing the sensitivity for some reduced atmospheres (i.e., Ar and air at 630 to 100 Torr and He at 300 Torr), the enhanced spectral intensity ultimately dropped off as the pressure was reduced below 10 Torr for all atmospheric compositions in the experimental arrangement used in this study. At all pressures of air and Ar, the plasma temperature remained rather constant with increased inter-pulse delays; however, the plasma temperature was more variable for different He gas pressures and inter-pulse delays.

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“…Laser-induced breakdown spectroscopy (LIBS) is becoming an increasingly popular technique for fast analysis of materials in industrial, 1 security, [2][3][4] forensic, 5,6 and exploratory applications. 7,8 One limitation of LIBS technology in portable applications [9][10][11] is the size of the fiber-optic spectrometers used to analyze LIBS signals.…”

Section: Introductionmentioning

confidence: 99%

Utilization of the Coherence Function with Welch's Method for Signal Analysis in Low Resolution Laser-Induced Breakdown Spectroscopy

O'Leary

Kelley

2010

Appl Spectrosc

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This work presents a technique by which a low resolution ( approximately 1 nm) fiberoptic spectrometer may be used to definitively identify elements and molecular fragments in laser-induced breakdown spectroscopy. Commercial laser-induced breakdown spectroscopy (LIBS) spectrometers have high resolution in the area of spectral interest, and software is used to identify elements via a look-up table containing known spectral lines. When analyzing spectra from a lower resolution fiber-optic spectrometer, software based on look-up tables can produce erroneous results, reporting elements absent from the sample. As a solution to this problem, an analysis using the coherence function in conjunction with Welch's method is used to compare sample spectra with a library of reference spectra, which contain peaks primarily from a single element. The analysis has proved to be adept at identifying specific elemental signatures in multi-component samples. The technique leverages the increased information content of concomitant atomic emission lines, which are easily collected with a low resolution broadband (200-1100 nm) fiber-optic spectrometer. This technique alleviates the need for the user to visually verify the vicinity of individual peaks during testing. While Pearson's method is generally used for this type of analysis, we show that Welch's method has the advantage of being less susceptible to problems caused by continuum background.

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Laser-Induced Breakdown Spectroscopy of Steels at Atmospheric Pressure and in Air

Cited by 30 publications

References 5 publications

Laser-Induced Breakdown Spectroscopy for Real-Time Detection of Halon Alternative Agents

Laser-Induced Breakdown Spectroscopy for Real-Time Detection of Halon Alternative Agents

Effect of atmosphere on collinear double-pulse laser-induced breakdown spectroscopy

Utilization of the Coherence Function with Welch's Method for Signal Analysis in Low Resolution Laser-Induced Breakdown Spectroscopy

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