LIBS of several gaseous components (N2, Ar, air and SF6) in different pressures

In this work, an irxadiance chamber is used to study LIBS of several gaseous samples such as air, pure Ar, N₂ and SF₆ in different pressures by means of a fundamental harmonic of Nd:YAG laser and CCD spectrograph. Delay time and repetition rate are set 1mus and 5Hz. Plasma temperature was extracted from Boltzmann equation and the corresponding electron density was estimated using stark broadening. For reducing the fitting error and by regarding single Ne assumption, the fit averaged over several lines. Discrepancy between obtained Ne and Ne measured from Saha equation is discussed. Integrated intensity versus pressure was plotted so for improving the precision SNR and RSD% were determined at various pressures. Finally extraordinary behavior of SF₆ in comparison with other gases is discussed according to deviation from ideal gas and dominant processes in plasma formation in different pressures.