Irradiation-induced amorphization of graphite: a dislocation accumulation model

We present a kinetic model to explain irradiation-induced phenomena in graphite up to a high dose of amorphization. We attribute the origin of amorphization to the accumulation of dislocation dipoles instead of a disordered region assumed in a previous model by Niwase. Calculated results for the change in a sample dimension up to amorphization and the Raman intensity ratio in a low-damage range compare favourably with the experimental results, revealing the existence of a barrier inhibiting the mutual annihilation of an interstitial and a vacancy.