Influence of proton irradiations on Fe track stability in silicates

Abstract
Muscovite mica and labradorite crystals have been irradiated by 1013-1014 cm−2 protons (12 MeV) and ∼106 Fe ions (1.9 MeV/amu). Three types of samples were prepared, having received respectively: (i) Fe ions only; (ii) protons followed by Fe ions; (iii) Fe ions followed by protons. The annealing behavior of Fe tracks was studied in the three types of samples. In samples first irradiated with high doses of protons, Fe tracks anneal at a higher temperature than in the other samples. We discuss implications on track formation mechanisms and the enhanced stability of fossil tracks compared to artificial tracks.