Biophysics with electrons
In recent years there has been a significant level of interest in the way in which low energy secondary electrons, a by-product of high-energy ionising radiation, can inflict damage in human tissue. It has beenfound that electrons with energy well below the ionisation potential can cause strand breaks, through a process called dissociative attachment, whereby a low energy electron attaches to a molecule in the DNA chain to form a temporary anion state (or negative ion resonance) which then dissociates into a negatively charged and neutral fragment, both of which can be highly reactive free radicals.
The goal of this particular research program in CAMS is to understand more about the formation of these resonances and the breakup process that follows. In particular, studies using the crossed beam spectrometer at ANU will identify resonances in electron scattering from targets such as tetrahydrofuran and the DNA bases - guanine, thymine, cytosine and adenine, all of which are important components in the DNA double helix. It is hoped that a better understanding of the details of electron interactions with these targets that a more detailed picture can be built of radiation damage within living tissue.
Our particular contribution will be to quantify this role for the elastic scattering and vibrational excitation channels. In this project new techniques, in particular the incorporation of a new beam source for the bio-molecules, will be applied to the study of bio-systems in order to provide benchmark electron cross section measurements. Measurements of the break-up fragments will also be incorporated into the experimental program.
