Nanodosimetry of 125I – Auger electrons – Experiment and modeling

The experiment with 125I-Auger electrons, interacting with gaseous nitrogen with size equivalent to segment of DNA in mass per unit area scale, are described. The discrete ionization cluster-size distributions have been obtained. The shapes of which are definitely determined by the size of the interaction volumes. The volume sizes studied in the present work are comparable with a segment of DNA and of nucleosome. The experiments have been carried out with the set up, called Jet Counter, and are the first cluster-size distributions as yet measured for an Auger-electron emitter like 125I. The experimental results have been compared with those obtained by Monte Carlo simulation. The results for 125I have been compared with calculated cluster size distribution for 131I.

► The results of nanodosimetric experiments using Auger electrons of 125I are presented.
► The cluster distribution of radiation is the primary source of radiation damage.
► The new descriptors of electron interaction at the DNA level are defined.