Effects of low energy carbon ions on plasmid DNA

The damage induced in supercoiled plasmid DNA molecules by low energy (< 1 keV u^-1) singly and doubly charged carbon ions has been investigated as a function of ion exposure. The production of short linear fragments through multiple double strand breakage is indicated and exponential exposure responses for each of the topoisomers are presented. The damage produced by C²⁺ is apparent at much lower ion exposures that with C⁺.