Desorption of gold nanoclusters (2-150Â nm) by 1Â GeV Pb ions

Nanodispersed targets of gold (grains sized at 2-150 nm) were irradiated with 956 MeV ions of Pb54+ ((dE/dx)e in gold 87 keV/nm). Ejected gold was gathered on collectors. Desorbed nanoclusters of gold were detected by means of TEM while the total matter transfer was measured by neutron activation analysis. For all the targets a part of ejected gold presents nanoclusters in the same size range as that of the grains on the corresponding targets. Desorption of nanoclusters with the size up to 90 nm was observed for the first time for atomic primary ions in the electronic stopping regime. The yield of the desorbed nanoclusters decreases from 22 to 1.4 cluster/ion with increasing the mean grain size from 6 to 30 nm. The total matter transfer measured for the target with the grain size 6-10 nm has a great value - ∼5 × 105 at./ion. Results are discussed.