Experimental tools for track structure investigations: new approaches for dosimetry and microdosimetry

In recent years, several new methods have been developed for track structure investigations. They use macroscopic gas volumes to transfer the results to microscopic dimensions and are based on either the cluster counting principle or on optical methods for full track analysis. The first type of method allows cluster size distributions in nanometre dimensions to be measured. The second type reveals the full topology of the ionisation pattern of tracks or track segments within a volume of a few micrometers with a spatial resolution down to 5 nm. The basic principles of these instruments and their main features are summarised and a selection of results obtained to date are shown. (author)