Annealing behaviour of ion tracks in olivine, apatite and britholite

Abstract

Ion tracks were created in olivine from San Carlos, Arizona (95% Mg2SiO4), apatite (Ca5(PO4)3(F,Cl,O)) from Durango, Mexico, and synthetic silicates with the apatite structure: Nd8Sr2(SiO4)6O2 and Nd8Ca2(SiO4)6O2 using 1.6 and 2.2 GeV Au ions. The morphology and annealing behaviour of the tracks were investigated by means of synchrotron based small angle X-ray scattering in combination with ex situ annealing. Tracks in olivine annealed above ∼400 °C undergo a significant change in track radius due to recrystallisation of the damage tracks. At temperatures higher than 620°C, the scattering images indicate fragmentation of the track cylinders into smaller subsections. Ion tracks were annealed at elevated temperatures up to 400°C in the Durango and Ca-britholite, and up to 560°C in Sr-britholite. While there was a significant change in the track radii in the Durango apatite, tracks in the two synthetic samples remained almost unchanged.