Absolute yields and angular distributions of gold nanoclusters (2–22 nm) desorbed due to electronic processes by fast heavy ions from nanodispersed gold targets

Yields and angular distributions of gold nanoclusters in the size range 2–22 nm desorbed from nanodispersed islet targets of gold by single 252Cf fission fragments (FF) were measured. It is shown that the angular distributions are narrow, stretched normally to the target surface and are well described by the function dn/dΩ=g(θ)∼exp(−kθ)×cos(θ). When the mean cluster size 〈d〉 increases from ∼3 to 21 nm, the mean polar angle 〈θ〉 decreases from ∼45° to ∼21° as 〈θ〉=(a+b)/〈d〉2 and the cluster yields Y decrease from 3 to 0.3 clusters per FF as Y(〈d〉)=A(1/〈d〉−1/dthr) (A≈16.5nm/FF,dthr≈39nm). Parameter dthr is interpreted as a size threshold of cluster desorption. The results are discussed.