Analysis of Atomic Beams Produced by Laser-Induced Ablation

Pulsed atomic beams with flux densities above 10 16 cm -2 s -1 have been produced in vacuum with high reproducibility by laser induced ablation from titanium and iron targets. The power of the TEA CO 2 laser was kept at a level where plasma production at the target surface was avoided: no ions were detectable. The beams were analysed by laser fluorescence. The high directionality of the beam, a discrepancy between velocity distribution and flux density as well as very low excitation temperatures of the fine structure levels of the ground state point to a non-thermal ejection process of the atoms and/or to impurity surface effects.