Annealing kinetics of latent particle tracks in Durango apatite

Abstract

Using synchrotron small angle X-ray scattering we determine the 'latent' track morphology and their annealing kinetics in the Durango apatite. The latter, measured during ex situ and in situ annealing experiments, suggests structural relaxation followed by recrystallisation of the damaged material. The resolution of fractions of a nanometer with which the track radii are determined, as well as the non-destructive, artefact-free measurement methodology shown here, provides a new means for in-depth studies of ion-track formation in natural minerals under a wide variety of geological conditions.

Morphology and annealing kinetics of ion tracks in minerals

“…An additional term was added when calculating the scattering intensity taking into account a roughening of the track boundaries during the annealing process [17],…”

“…Small angle X-ray scattering (SAXS) provides an alternative technique to study ion track damage as it measures density changes at the nanometre scale. We have recently demonstrated, that SAXS can provide previously unresolved details of the track structure in amorphous SiO 2 [14][15][16], metallic glasses, and natural apatite [17][18][19]. Using in situ and ex situ annealing experiments, we have demonstrated that SAXS is well suited for determining the annealing kinetics of ion tracks [17].…”

“…To study the annealing kinetics of the ion tracks, we have performed isochronal annealing experiments as a function of temperature (ex situ) and isothermal annealing as a function of time (in situ) on the sample irradiated with 2.2 GeV Au ions [17]. For the ex situ annealing measurements, part of the sample irradiated with Au ions was sequentially annealed at temperatures between 200 and 500 °C for 30 min under ambient conditions.…”

“…A narrow Gaussian distribution of track radii was implemented to account for deviations of perfectly aligned cylindrical tracks [17]. The solid lines in figure 2 show the analytical fits to this model.…”

SAXS study on the morphology of etched and un-etched ion tracks in apatite

“…At this facility it is also possible to generate ion tracks under high pressure and high temperature conditions. Previous studies in our group focussed on the variations in un-etched track morphology characterised by synchrotron based small angle x-ray scattering (SAXS) [3,4]. SAXS is a non-destructive technique used to study the size, orientation and spatial arrangement of nano-to micro-sized objects.…”