  Experiments with multiwalled carbon nanotubes and graphite as targets in a
source of negative ions with cesium sputtering have shown that nanotubes with
nanometer radii and micrometer length can be compared with micrometer size
graphite grains to understand the irradiation effects that include the
formation, sputtering of carbon clusters and the resulting structural changes.
The simultaneous adsorption of cesium on the surface and bombardment by
energetic cesium ions is shown to play its role in the cluster formation and
sputtering of carbon atoms and clusters and the cesium substituted carbon
clusters as anions. Qualitative and quantitative sputtered species outputs are
related to their respective structures. Structural changes are shown to occur
in MWCNTs and seen in SEM micrographs. The individual identity of the heavily
bombarded MWCNTs may have given way to the merged structures while effects on
the structure of heavily irradiated graphite grains size needs to be further
investigated
