Simulation of atomic and ionic absorption and emission spectra for thermal plasma diagnostics: application to a volatilisation study in a plasma jet

摘要

Simulation of atomic emission and absorption spectra has been carried out in order to improve and to check the validity of measurement techniques and data processing for plasma diagnostic. Doppler, Van der Waals, Stark and instrumental broadenings and shifts have been taken into account. The effect of self-absorption has also been considered. The input parameters are pressure, temperature, electron density, and emitting species number density. In such calculations data needed for the determination of collisional and Stark broadenings are not always available. An empirical method of data evaluation is described and discussed. The limits and the precision of this modelling are discussed with experimental examples. This simulation method has been applied to the diagnostic of volatilisation phenomena in thermal plasma spraying processes. It has been used to assist in the choice of diagnostic lines, instrumental parameters and data processing parameters. It has also been used to evaluate the accuracy of the temperature and density distributions calculated from spectroscopic measurements.