Models of radiation damage in diamond were developed, for electron- and γ-irradiation, by using Monte Carlo computer simulations. The energies which were investigated ranged from 0.25 to 10MeV for electron irradiation, and from 1 to 15MeV for γ irradiation. It was noted that electrons had a low collision cross-section with C atoms, and that much of their energy was therefore dissipated in ionization before the electron displaced an atom. The γ radiation caused damage via an indirect process which involved the generation of electrons (by Compton scattering and pair production) which then displaced atoms and ionized the material. The knock-on atoms could cause further damage by displacing yet more atoms. However, both electron and γ radiation mainly created isolated vacancies and interstitials (Frenkel pairs). The range of 1MeV electrons in diamond was about 1.3mm, with a nearly constant damage profile up to this cut-off point. The range of γ photons was much greater, with about 85% of 1MeV photons passing through a 5mm-thick diamond without causing any damage. The total damage rates were predicted to vary from 0.01 to 5.15 vacancies per incident electron, and between 0.02 and 6.10 vacancies per photon over the energy ranges investigated.

Radiation Damage of Diamond by Electron and Gamma Irradiation. B.Campbell, A.Mainwood: Physica Status Solidi A, 2000, 181[1], 99-107