The growth of gas bubbles in solids under irradiation at elevated temperatures around 0.5 Tsub(m)

This paper reviews experimental observations and theoretical models on bubble growth due to gas atom and vacancy absorption as well as due to coalescence. In order to get an improved insight into the mode of bubble growth and motion, the experimental results on bubble distributions are correlated with those calculated from current models based on the Chandrasekhar equation for the coagulation of colloids in a short time interval. By modifying the original assumptions made by Gruber for the case of gas bubble migration and coalescence, it was shown that in the case of annealing experiments of cold helium-implanted samples the experimental data can be matched by using an analysis based on that equation. However, under different experimental conditions, i.e. hot implantation or dual-beam irradiations, the model fails due to the Gruber assumption of a zero production rate, i.e. due to assumption of a constant number of gas atoms during the coalescence process. Replacing that limitation by introducing a continuous gas production term, the model predicts a bimodal bubble size distribution, which was postulated and observed in experiments. (author)