Spatial and temporal probing of a laser-induced plasma plume by cavity ringdown spectroscopy

Krstulović, Nikša; Cutic, Nino; Milošević, Slobodan

doi:10.1016/j.sab.2008.07.004

Cited by 14 publications

(5 citation statements)

References 33 publications

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“…Since photons absorbed by helium atoms within the cavity move back and forth, the Doppler broadening is enhanced for atoms moving in the radial direction (parallel to the sample surface and the cavity axis). This effect connected to the nature of CRDS detection of atoms in divergent beams has been discussed in more detail in Krstulovic et al [49].…”

Section: Resultsmentioning

confidence: 89%

Metastable helium atom density in a single electrode atmospheric plasma jet during sample treatment

Zaplotnik

Bišćan

Popović

et al. 2016

Plasma Sources Sci. Technol.

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The metastable He atoms play an important role in atmospheric pressure plasma jet (APPJ) chemistry processes and in the plasma generation. This work presents cavity ringdown spectroscopy (CRDS) investigation of metastable helium atom (2 S 3 1 ) densities in a single electrode APPJ during sample treatment. A spatially resolved density distribution of a free jet (without sample) was measured at a He flow rate of 2 slm. The maximum measured density of a free jet was around × 7 10 11 cm −3 . With the insertion of a sample the densities increased up to 10 times. Helium metastable atoms, in a single electrode helium APPJ (2 slm, ≈2.5 kV, pulsed DC, 10 kHz repetition rate), decayed exponentially with a mean lifetime of ± 0.27 0.03 μs. Eight different samples of the same sizes but different conductivities were used to investigate the influence of a sample material on the He metastable densities. The correlation between sample conductivities and metastable He densities above the sample surface was found. Metastable He density can also be further increased with decreasing sample distance, increasing conductive sample surface area and by increasing He flow.

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Section: Resultsmentioning

confidence: 89%

Metastable helium atom density in a single electrode atmospheric plasma jet during sample treatment

Zaplotnik

Bišćan

Popović

et al. 2016

Plasma Sources Sci. Technol.

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“…In order to improve the signalto-noise ratio, measured ring-down waveforms are to be averaged, usually using from 10 to 100 samples. In practice, time resolution can easily be 100 ns or even lower [64][65][66]. To obtain a good fit it is important to have not only a good time resolution of a digital oscilloscope but also vertical resolution (>8-bit).…”

Section: Setting Up the Experimentsmentioning

confidence: 99%

“…Molecules were also detected within the plasma plume [87,88], as were atoms within the dark region of the plasma plume [89]. A spatially and temporally resolved study of single-and double-pulsed plasma was carried out [64,90,91] and helium metastable density determined upon helium excitation by electrons ejected from various target materials [92]. The latter case of LPP shows similarities with APPJ due to pulsed plasma nature and timedependent absorptions.…”

Section: Crds Propertiesmentioning

confidence: 99%

Cavity ring-down spectroscopy for atmospheric pressure plasma jet analysis

Zaplotnik

Bišćan

Krstulović

et al. 2015

Plasma Sources Sci. Technol.

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Pulsed cavity ring-down spectroscopy (CRDS) is a direct absorption, highly sensitive, versatile technique suitable for the analysis of a wide range of plasmas. CRDS belongs to a wide class of cavity-enhanced spectroscopies. This work briefly describes the basic principles of CRDS and summarizes the main literature specifically related to applications for atmospheric pressure plasma jets (APPJ). Emphasis is given to the temporal resolution and pulsed character of the plasma sources. As an example we present in more detail the determination of metastable helium density in the 2s S 3 1 state produced in a single-electrode atmospheric pressure plasma jet driven by a pulsed high-voltage waveform. Measured He( S 3 1 ) number densities ranged from × −

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“…Here, it was shown that the same analytical performance could be obtained as with a commercial Echelle-intensified charged-coupled device detection system. Also, a spatial and temporal probing of a laser-induced plasma plume by cavity ringdown spectroscopy has been described (139). Here, a model was developed to perform a forward convolution of atomic absorption line profile measurements.…”

Section: Laser Induced Breakdown Spectroscopymentioning

confidence: 99%