Track production in cellulose nitrate by protons, H2+ molecules and low energy heavy ions

Cellulose nitrate film has been irradiated with protons, H2+ molecular ions, and low energy heavy ions and the tracks produced have been observed using the chemical etching technique. The energy region over which protons can produce tracks in cellulose nitrate has been found to extend from 0.02 MeV up to 2.2 MeV. The detection efficiency gradually decreased for energies above approximately 1.0 MeV but no sharp threshold was observed. The low energy limit could not be investigated as tracks were observed for the lowest energy (0.02 MeV) at which a stable beam could be obtained. For the same energy/nucleon the tracks of H2+ molecular ions had the same diameter as those of protons and no effects of the presence of the second proton could be detected. Low energy heavy ions, which were losing energy mainly through nuclear collisions, were found to produce etchable damage in cellulose nitrate. Individual tracks were observed for Kr+ ions with energy 0.95 keV/nucleon and the etched irradiated area was observed down to 0.6 keV/nucleon. (author)