Modeling of laser induced breakdown spectroscopy for very low-pressure conditions

Antony, Joseph; Jatana, Gurneesh S.; Vasa, Nilesh J.; Raja, Vignesh; Laxmiprasad, A. S.

doi:10.1007/s00339-010-5782-1

Cited by 14 publications

(6 citation statements)

References 9 publications

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“…40 Studies have been performed that show the peak temperatures of laser produced plasma regardless of pressure are the same; however, in reduced pressures, the plasma expands at faster velocities and cools faster. 41,42 Equally consistent with this, our results could also show that the plasma persists for shorter times in reduced pressure and results in reduced line intensities.…”

Section: Description Of the Spectra And Atmospheric Impactssupporting

confidence: 91%

Effects of Laser Beam Focusing Characteristics on Laser-Induced Breakdown Spectra

2020

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The impact of altering laser focusing conditions on laser-induced breakdown spectroscopy experiments is investigated under ambient Earth laboratory and simulated Martian atmospheres. Experiments were performed in which the focal spot size was varied on a sample by altering the lens to sample distance with respect to targets of interest. Samples investigated include aluminum, copper, and steel. Specific neutral and ionic transitions of each sample were monitored. Atomic and ionic emissions show different intensity peak distributions along the varying lens to sample distance. Ionic species have peak emissions when laser plasma is initiated with a focused spot within the sample in ambient Earth laboratory air, while atomic emissions have peak intensities several millimeters deeper into a sample. In simulated Martian atmospheres, atomic emissions are observed to peak when the laser is focused within the sample, while ionic emissions have peak intensities when the laser is focused near the surface of a sample.

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Section: Description Of the Spectra And Atmospheric Impactssupporting

confidence: 91%

Effects of Laser Beam Focusing Characteristics on Laser-Induced Breakdown Spectra

2020

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“…Such an assumption is somehow supported by theoretical papers where it is demonstrated the almost constant plasma temperature and front expansion during the first millimeter of the plasma as long as a certain base pressure has been reached. 19…”

Section: Resultsmentioning

confidence: 99%

Pressure Effects in Laser-Induced Plasmas of Trinitrotoluene and Pyrene by Laser-Induced Breakdown Spectroscopy (LIBS)

2014

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The influence of the ambient atmosphere on the dynamics of plasma expansion, besides the interaction between excited plasma and gas molecules, has been studied for specific organic aromatic compounds. To analyze the influence of air on the formation pathways of atomic and molecular species inside the plasma plume, the spectral emissions in laser-induced breakdown spectroscopy (LIBS) of 2,4,6-trinitrotoluene (TNT) and pyrene were compared at different pressure environments, from high vacuum to atmospheric pressure. Pelletized samples of the compounds were introduced in a vacuum chamber for excitation with the fourth harmonic output of an Nd : YAG laser (266 nm). The optical emission signal was collected with an optical fiber connected to a spectrograph fitted with a intensified charge-coupled device detector. Results from LIBS spectra indicate that changes in pressure level affect the kinetics of the characteristic excited species and their spatial distribution inside the plasma plume.

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“…The plasma passes by the optical eld of view of the spectrographic system with a specic velocity (generally 10 5 to 10 6 cm s À1 ) so this requires fast dynamic detection and gives short temporal duration. 16 Concerning the lifetime of ions presented in the plasma (Fig. 3, top right), the minimum time resolution achievable was 800 ns to allow proper ion extraction.…”

Section: Resultsmentioning

confidence: 99%

“…4a summarizes the data corresponding to the evolution of four atomic species (H, C, N and O) with uence. The signals corresponding to 1 H + , 12 C + , 14 N + and 16 O + were recorded in the mass spectrometer, whereas the emissions at 656.28 nm, 247.82 nm, 746.82 nm and 777.42 nm were used for H, C, N and O, respectively. The four wavelengths selected correspond to emissions from excited states of the neutral atom.…”

Section: Resultsmentioning

confidence: 99%

Laser-induced plasma spectroscopy of organic compounds. Understanding fragmentation processes using ion–photon coincidence measurements

Delgado

Vadillo

Laserna

2013

J. Anal. At. Spectrom.

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Coincidence detection is of interest to get as much information as possible about transient events occurring in laser induced plasmas. The present work is focused on coincidence ion-photon detection of laser plasmas of high-energy organic compounds (TNT and DNT) in a condensed phase irradiated with UV laser pulses using an advanced instrument for simultaneous monitoring of both types of chemical species generated. The optical emission spectrum is acquired from atoms, atomic ions and diatomic molecules, whereas the mass spectrum derives from fragment ions of the molecule. These fragments result from direct ionization or may be formed through indirect pathways. Fluence-resolved experiments showed the evolution of the main optical-mass signals in the acquired spectra for a limited energetic range, showing the different stages of lifetime of plasma: the rising thresholds and extinction of the different atomic and molecular studied species, besides the breakage of the aromatic ring and the later excitation of ionic species at a higher fluence level.

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Modeling of laser induced breakdown spectroscopy for very low-pressure conditions

Cited by 14 publications

References 9 publications

Effects of Laser Beam Focusing Characteristics on Laser-Induced Breakdown Spectra

Effects of Laser Beam Focusing Characteristics on Laser-Induced Breakdown Spectra

Pressure Effects in Laser-Induced Plasmas of Trinitrotoluene and Pyrene by Laser-Induced Breakdown Spectroscopy (LIBS)

Laser-induced plasma spectroscopy of organic compounds. Understanding fragmentation processes using ion–photon coincidence measurements

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