ABSTRACT
The relevance and significance of clustered DNA damage, defined as two or more lesions formed within 1–2 helical turns of DNA by a single radiation track, to various biological effects are now widely accepted. However, it is still unknown how a given type of radiation, for example, an ion particle, causes clustered DNA damage. Here, we describe our simulation results of very fast processes immediately following ion irradiation, and the importance of unravelling the physical process immediately after ion particle irradiation. We suggest that laser-driven ion particles can be used to clarify the very fast physical process. Two possible pump-probe schemes for picosecond time-resolved measurements after laser-driven ion irradiation are discussed. The first is time domain THz spectroscopy, in which the effect of a heavy ion-induced strong electric field on the movement of polar molecular ions can be investigated. Second is the time-resolved X-ray small angle scattering technique (SAXS), in which the clustered molecules or holes generated in water could be detected. The very fast processes immediately following ion particle irradiation of water/cells remains an important area to be investigated in order to understand the underlying early stage mechanisms of ion-particle induced biological effects, particularly the formation of clustered DNA damage.
