Eur. Phys. J. D 32, 19-24 (2005)
https://doi.org/10.1140/epjd/e2004-00150-y

Contribution of ion emission to sputtering of uranium dioxide by highly charged ions

Monomers and cluster size distributions

Centre Interdisciplinaire de Recherche Ions Lasers CIRIL, UMR 6637 (CEA-CNRS-ENSICAEN), boulevard Henri Becquerel, 14070 Caen Cedex 05, France

Corresponding author: ^a rothard@ganil.fr

Received: 8 April 2004
Revised: 7 September 2004
Published online: 3 November 2004

Abstract

Measurements of the cluster size (n) distribution of secondary (UO ions from sputtering of uranium dioxide (UO by Ne⁸⁺, Ar⁸⁺ and Xe ions (q=10, 23) at fixed kinetic energy (81 keV) have been performed with a time-of-flight mass spectrometer. The cluster ion yields Y follow a power law with . This is in contrast to a statistical recombination of the constituents upon ejection, but in agreement with the predictions of collective ejection models. Such a power law was also observed in the electronic stopping regime with MeV/u ions. The exponent  is found to decrease with increasing projectile mass (and thus total sputter yield) at fixed kinetic energy. The ratio of emitted ionic clusters to monomers varies from 3 to 4.5 depending on the projectile. The contribution of positive ions to the total sputtering yield amounts to about 0.03%.