Plasma diagnostics with semiconductor lasers using fluorescence and absorption spectroscopy.

摘要

Plasma diagnostics based on fluorescence and absorption spectroscopy using narrow-bandwidth semiconductor lasers have been developed in a 1-kW atmospheric-pressure inductively coupled plasma torch. Measurements of species and electron number density, atom (T) and electron (T;The agreement between atom and electron kinetic temperatures, inferred from the Doppler-broadening lineshape component and the Stark width/shift ratio, respectively, suggests that all species are in translational equilibrium. The relationship between 4s-population temperatures, inferred from integrated absorption coefficients, and the kinetic temperature suggests that the argon individual 4s-state populations are in mutual equilibrium at levels which are higher than the local thermodynamic equilibrium value at the kinetic temperature. Electron number density values, determined from Stark width and shift measurements, are significantly higher than calculated Saha-equilibrium values at the kinetic temperature, thereby indicating the presence of an elevated electron population. The measured 4s-population was less than 25% of the value in partial local thermodynamic equilibrium with the measured electron number density at the kinetic temperature. Saturation intensity values were inferred from variations in the linecenter, linewidth, and integrated lineshape values of partially saturated profiles with laser intensity. Quench rates, determined from saturation intensity values, were in good agreement with calculated values of collisional transfer rate, when measured kinetic temperature and electron number density values were used as input parameters.;Emission diagnostics enabled a determination of the excitation temperature (T