Track separation due to dissociation of MeV C-60 inside a solid

Samples of yttrium iron garnet were irradiated at 300 K with 10-40 MeV Au-4 and C-60 ions at normal and grazing incidences. The samples were then observed in a transmission electron microscope. It is seen that the cluster ions create large size amorphous continuous tracks and that strong sputtering occurs. Irradiations at grazing incidence allow direct observations of the track shape evolution as the projectiles slow down in the target. For the first time it was possible to visualize the dissociation of C-60 ions inside a solid. The stochastic nature of this separation process results in tracks of different shapes and lengths. The tracks generated in the target keep a constant diameter during the correlated slowing-down of the C-60 projectile constituents during travelled distances L-const approximate to 100 nm, although the area on which the constituents are spread increases by almost two orders of magnitude between the target entrance and the depth L-const. (C) 1997 Elsevier Science B.V.