ION INDUCED SELF-DIFFUSION OF CARBON

Mixing and diffusion of **1**3C marker atoms in a **1**2C graphite matrix has been studied as a function of temperature 10 to 1500 K under the influence of bombardment with 70 to 150 kev **1**2C** plus and 13 to 20 kev D** plus ions. At temperatures between 10 and 220 K the mixing of the marker atoms is weak, but probably still stronger than pure ballistic mixing. Around room temperature the evaluated diffusion coefficient increases steeply towards a plateau value which is constant up to 1100 K. Above 1100 K the diffusion coefficient increases monotonically with temperature. This temperature dependence can be understood within a model taking into account mobile defects like interstitials and vacancies and their mutual recombination.