Thermal stability and chemical reactivity of defects produced in silicates by high energy heavy ions

For several years we have studied the defects formed by high energy Fe, Kr and Xe ions in silicates using two complementary methods: small angle X-ray scattering, from which the size and the linear density of defects can be determined, and the classical track etching method, which relies on the enhanced chemical reactivity induced by the defects. To achieve a better understanding of the processes involved, these studies have been extended to much heavier ions (Au and U) in monocrystals of labradorite and muscovite. Unfortunately, owing to the large size of the crystals the defects could not be observed with the present wavelength of the small angle X-ray scattering apparatus. Our main results have thus been obtained using the track etching method. The thermal behavior and chemical reactivity of these tracks show that the latent track is now a continuous cluster of defects, similar to an amorphous phase, along part of the range. From these results, we tentatively assess the relation between energy loss and defect production in silicates. (author)