Scanning force microscopy study of surface tracks induced in mica by 78.2-MeV 127I ions

Tapping mode scanning force microscopy has been employed for the first time to image the radiation damage tracks on muscovite mica due to individual, normally incident 78.2-MeV I-127 ions from the Uppsala EN tandem accelerator. Conical-shaped hillocks having nearly circularly-shaped bases with mean width 20+/-2 nm and mean height 0.5+/-0.2 nm have been observed. Similar types of hillocks have been observed in the contact mode both in air and under water. The absence of lattice structure on the tops of the hillocks indicates the formation of an amorphous region as a result of the expansion created by the passage of each ion. The presence of a crater beneath a hillock has been observed after the hillock was erased using strong interactions between the scanning force microscope probe tip and the surface.