Measurements of gain and line broadening in lithiumlike aluminum

Spectroscopic measurements were made of lithiumlike Al emission lines from laser-produced plasmas. Flat targets, consisting of thin layers of Al coated on a Mylar backing, were irradiated with up to eight beams of the OMEGA laser system employing a line-focus configuration. The Al x i 4f-3d line at 154.7 Å exhibited a gain coefficient of 4.1±1.2 ${\mathrm{cm}}^{\mathrm{-}1}$ from comparisons of line intensities from 3- and 6-mm-long plasmas. Similarly, the 4d-3p line at 150.7 Å and the 5f-3d line at 105.7 Å had gain coefficients of 4.5±1.3 and 3.5±0.8 ${\mathrm{cm}}^{\mathrm{-}1}$, respectively. The linewidth of the 5f-3d line was measured to be 0.35 Å, which is much larger than the expected Doppler and instrumental width and can be attributed to Stark broadening. This Stark broadening corresponds to an electron density of 3×${10}^{19}$ ${\mathrm{cm}}^{\mathrm{-}3}$.