We have observed direct target ionization of He at low velocity (0.2 t
o 1.7 a.u.) by highly charged ions of C6+, N7+, O8+, Ar16+, and Xe30+.
The measured single ionization cross sections increase rapidly with i
ncreasing velocity. The cross sections, divided by the charge of the i
ncident projectile, are found to lie on a universal curve when plotted
versus the ratio of the projectile velocity to the classical Bohr-Lin
dhard velocity limit for ionization. Impact parameter information was
determined for O8+ on He collisions and suggests that single target io
nization happens over an impact parameter range very similar to that f
or single capture.