A Molecular Dynamics Study of Temperature Dependence of the Primary State of Cascade Damage Processes

In this work, the temperature effects on the primary state of cascade damage processes were investigated using molecular dynamics simulation method for gold. For this purpose, the simulations were carried out using the molecular dynamics code GRAPE to control the initial irradiation temperatures of a computational cell. At higher temperature, more displaced atoms are produced since an effective threshold displacement energy is lower. However, most of them are unstable defect pairs due to the shorter separation of interstitial atom and vacancies, so that the quenched cascade defect fraction (QDF) is reduced with higher temperature irradiation. The short interstitial- vacancy separation at higher temperature is predominantly observed in the length of replacement collision sequences RCSs. The assisted focusing process is stable against the large thermal lattice vibration at higher temperature.