  The conventional treatment of the Bethe-Bloch equation for protons accounts
for electron capture at the end of the projectile track by the small Barkas
correction. This is only a possible way for protons, whereas for light and
heavier charged nuclei the exchange of energy and charge along the track has to
be accounted for by regarding the projectile charge q as a function of the
residual energy. This leads to a significant modification of the Bethe-Bloch
equation, otherwise the range in a medium is incorrectly determined. The LET in
the Bragg peak domain and distal end is significantly influenced by the
electron capture. A rather significant result is that in the domain of the
Bragg peak the superiority of carbon ions is reduced compared to protons.
