An approach to experimental microdosimetry at the nanometre scale

An experimental set-up called ''Jet Counter'' has been built for studying the microdosimetry pattern of the interactions of charged particles with nanometre-size gas volume. Such nanometre-size gas volume (in unit density scale) have been produced in a device consisting of a pulse operated valve which injects gas in the form of an expansion jet into an interaction chamber. The range of the effective thicknesses of the obtained simulated nanometre sites was from a tenth to 250 nm. The mean values of energies deposited in simulated sites of 11 and 36 nm, irradiated by 700 eV monoenergetic electrons, have been determined in the experiment. (author)