PARTICLE VELOCITIES AT THE COMPLEX SOLIDS LASER-ABLATION IN VACUUM AND IN GAS AMBIENTS

The comparative study of the laser ablated Y-Ba-Cu-O high T-c supercon ductor, PbTe(Ga) semiconductor and Sn(Cu) metallic alloy has been carr ied out using a YAG:Nd3+ Q-switched laser, an electrostatic probe and OMA in a region of laser power up to 4.8 J/cm(2) and in a region of ar gon or oxygen pressure up to 0.5 Torr. Ion and electron velocity distr ibutions have been obtained from the probe measurements. Vapor composi tion and temperature were studied from optical emission spectra. The n eutral particle velocity distributions have been calculated from TOF Q MS measurements for PbTe(Ga) reported earlier. Two fluxes of the charg ed particles exist in the region of p = 20-100 mTorr: the flux of slow ions and electrons scattered onto the gas molecules, and the flux of the fast non-scattered particles. The position of the ion peaks on the time scale and the average cross section of the scattering in a gas d epended on the target material.