  Three questions should be interesting, for better understanding of the basic
physics of damage creation and stopping ions of different types, in the damaged
tube: 1) Between the mass and charge effects, i.e. potential- independent and
potential- dependent effects on the damaged tube, Which ones may the cross-
section $\sigma$ effects belong to? 2) One method has calculated number of
energetic recoils (both ions and carbon atoms), which hit the metal layer below
the damaged tube, to study the stopping of both incident ions and recoil carbon
atoms in it. Another method has calculated the ion- deposited energy
$E_0-E_{penetrating}$ in the damaged tube, to distinguish between penetrating
and stopped ions. Which method is better for studying the stopping between two
ones? 3) Why can tens of the graphitic shells easily stop energetic ions with
energies up to 10 keV? Which effects on the stopping? In kinetic energy
formulas, we give answers for discussion.
