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

Autori
Zaplotnik, Rok ; Bišćan, Marijan ; Popović, Dean ; Mozetič, Miran ; Milošević, Slobodan

Izvornik
Plasma Sources Science and Technology (0963-0252) 25 (2016), 3; 035023, 10

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
atmospheric plasma jet ; cavity ring-down spectroscopy ; helium metastable density ; optical emission spectroscopy ; electromagnetic measurements

Sažetak
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 ring-down spectroscopy (CRDS) investigation of metastable helium atom (23S1) 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 7×1011 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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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