INVESTIGATIONS TOWARDS EVALUATING THE CONTRIBUTION OF (ALPHA+AL,SI) INTERACTIONS TO FOSSIL TRACKS IN MUSCOVITE MICA TRACK DETECTORS

In order to characterize the tracks in the muscovite mica detector gen erated by Al and Si nuclei recoiling after the interaction with energe tic alpha particles from the decay chains of the U and Th present in t he mineral as impurities, two experiments have been performed: (1) irr adiation of the muscovite detectors with 6, 9 and 12 MeV alpha particl es produced by a Van de Graaff tandem accelerator, and (2) exposures o f the muscovite detectors to 8.8 MeV alpha particles from a Th chemica l compound under radioactive equilibrium. After irradiation, the musco vite detectors were chemically etched, and the tracks studied by optic al microscopy. Both experiments led to the conclusion that the recoili ng nuclei from interactions with high energy alpha particles have a tr ack pattern which is different from those presented by fission fragmen ts or heavy ions from cluster radioactivity.