Kinetic energy distribution of ions in the laser ablation of copper targets

In this work we report on a study of the plasmas produced in laser ablation of copper targets by XeF (lambda = 351 nm) excimer laser irradiation. The kinetic energy of positive ions was measured by energy resolved time of flight mass spectrometry. Average kinetic energies of the Cu(+) ions of the order of 1-30 eV were observed, as a function of the laser pulse fluence. The experimental kinetic energy distributions show a double-peak structure. The first located at very low kinetic energy (similar to 1 eV) can be related to a thermoionic component, whereas the second is strongly dependent on laser fluence. (C) 1998 Elsevier Science B.V.