A model was developed for O sub-system evolution in thin films of this material during  irradiation. The model took account of interactions between the defects which were formed, of inhomogeneity of the defect distribution (leading to the formation of 2 regions with differing O contents), and of saturation of the twin boundaries with O. By analyzing experimental data, it was estimated that the twin-boundary sink strength was about 9 x 1010/cm2, that the cross-section for O-vacancy formation due to ionization under  irradiation was about 3 x 10-19cm2, and that the energy barrier to O escape from the intercrystalline boundary was about 1.5eV.

D.V.Kulikov, R.A.Suris, J.V.Trushin: Superconductor Science and Technology, 1995, 8[5], 303-10