The radiolytic species created by the incident radiation are spatially deposited in a very nonhomogeneous manner, the radiation track structure. The radiation track structure is highly dependent on the type and energy of the incident radiation.
The first 3D simulations of the time evolution of an electron track during the non-homogeneous chemical stage were published in the 1980's. These simulations were difficult to perform at that time because computer power was inadequate. There is now a renewed interest for time evolution of 3D tracks, because these 3D images of radiation tracks are able to provide insight on spurs chemistry by direct visualization of chemical reactions.
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This is the radiation track video of a 300 MeV 12C6+ ion (LET ~ keV/μm), from ~10-12 to ~10-6 s. The left picture is the 3D track; the right picture is the XZ projection of the same track. Each dot represents radiolytic specie. The changes in color indicate chemical reactions.
These simulations, which are now much more accessible thanks to the phenomenal increase in computer power, will allow a better comprehension of the biological effects of radiation by linking the radiation track structure with biomolecular damage. This is of great interest for the growing field of heavy ion therapy in medicine and for space radiation protection.
The text and video are excerpted from the article Radiation Chemistry Primer by Ianik Plante, Ph.D.