Macrocluster effect caused by single multiply charged ions: masses of gold nanoclusters (3–30 nm) arising as a result of electronic processes induced by fission fragment bombardment in ultradispersed targets of gold

Abstract

Ultradispersed islet gold targets with mean sizes of islets within the range 5–20 nm are bombarded by 252Cf fission fragments (FF) in the electronic stopping regime. As a result, gold nanoclusters are ejected from the targets. By means of a collector technique using transmission electron and scanning force microscopies (TEM and SFM), sizes and masses of the clusters are measured. It is shown that the clusters have a practically perfect spherical shape and that their size distributions are similar to those of islets on the targets. Taking into account the quasi-spherical shape of such gold islets the results obtained testify to a desorption mechanism involving the formation of free metal clusters within the nanometer size range (3–30 nm) as result of relaxation of the electron excitation created by single FFs in target islets and the target itself.