STUDIES OF SILICON EROSION IN PLASMA-TARGET-INTERACTION FROM OPTICAL-EMISSION AND ABSORPTION-SPECTROSCOPY

The densities of eroded silicon from a target in interaction with a cy lindrically symmetric plasma are determined from measurements of the t ransverse radiance and transmittance of Doppler broadened spectral lin es with high spectral resolution. The transmission distributions, bran ching ratios, and the spectral line shapes, which depend on the optica l depths of the emitting and absorbing particles along the line of sig ht, are investigated for particle density and temperature determinatio n. First results on emission and transmission measurements of the Si I resonance multiplet spectral line branching ratios and line profiles (centered at 251 and 288 nm, respectively) for silicon as the erosion product from a C/C-SiC target in a low temperature plasma jet give abs orption coefficients, from which erosion rates can be deduced, which a re in good agreement with the results from the emission spectroscopy a nd from the gravimetric measurements.