The STARTRACK experiment

STARTRACK is the acronym of an experiment that aims to measure ionisation cluster distributions in nanometric sites placed at different distances from an accelerated charged particle track. STARTRACK will first use the 20 nm wall-less detector, already used for studying the nanometric track structure of an alpha particle, and then a new detector designed for measuring ionisation clusters in 10 nm sites. The experiment is mounted on the beam line of the Tandem-Alpi accelerator facility of the Legnaro Laboratories, which supplies ion beams from hydrogen to gold up to energy ranging from 7 to 28 MeV/amu. Track nanodosimetry aims to measure ionisation clusters along and aside the ion track down to occurrence probability of 10(-5). To reach such a goal at least 10(6) events have to be collected and the cluster pile-up probability has to be reduced to less than 10(-6). By using a beam profile detector, which is sensitive to very weak currents, and an event rejector counter, such an aim is feasible.