Application of a laser produced plasma: Experimental Stark widths of single ionized lead lines

Abstract

The optical emission spectroscopy from laser produced plasma generated by a 10,640 Å radiation, with an irradiance of 1.4 × 10 10 W cm − 2 on several lead targets, in vacuum and in an atmosphere of argon, was recorded and analyzed between 1900 and 7000 Å. The Local Thermodynamic Equilibrium conditions and plasma homogeneity have been checked. Stark widths for 31 lines of Pb II have been measured. These lines measured in this work correspond to the transitions 7s → 6p, n( n = 8, 9, 10)s → 7p, n( n = 7, 8)p → 7s, n( n = 7, 8)p → 6p 2, n( n = 7, 8)d → 7p, n( n = 5, 6)f → 6d, n( n = 5, 6)f → 6p 2. The population level distribution and the corresponding temperatures were obtained using Boltzmann plots. The plasma electron densities were determined using well-known Stark broadening parameters of spectral lines. Special attention was dedicated to the possible self-absorption of the different transitions. Temporal evolution of the plasma parameters was studied between 0.1 and 9 μs. Stark broadening parameters of the spectral lines were measured at 2.5 μs where the electron temperature was close to 11,300 K and the electron density to 0.8 × 10 16 cm − 3 . The experimental results obtained have been compared with the experimental and theoretical values given by other authors. A systematic trend of this parameter versus temperature of 4244.9 Å Pb II line has been presented.