COMPOSITION AND GAS-DYNAMICS OF LASER-ABLATED AIN PLUMES

The formation, composition and propagation of pulsed laser produced pl asma plumes from an AIN target have been studied in real time by spati ally and temporally resolved optical spectroscopy. The mean front velo city has been measured and appears to be slightly slower in the presen ce of added gas than in vacuum. In the initial stage of expansion, thi s velocity is almost the same for all neutral particles in the plume i n the initial stage of expansion. Velocities of neutral and ionic spec ies have been measured by their time of arrival from the target to a q uadrupole mass spectrometer and their expansion beam Maxwell-Boltzmann (MB) temperature determined. The plume electronic temperature has bee n determined by assuming a local thermodynamic equilibrium of the emit ting species.