Radiation induced electrical degradation in ceramics insulators

Radiation under the specific set of conditions has been shown to lead to severe electrical conductivity in insulators such as alumina. This study is devoted to examining the effects of radiation induced conductivity and electrical degradation in polycrystalline alumina and sapphire. Experiments were carried out at temperatures up to 823 K and an electric field of 500 kV/m. Experimental results show that radiation induced conductivity (RIC) in alumina consists of recoverable and permanent contributions when irradiated with charged particles. These two radiation induced effects are not completely separable and are functions of irradiation dose. In polycrystalline alumina, a significant increase in the permanent conductivity was observed after an incubation dose of 10-4 dpa. However only limited permanent electrical degradation was observed in single crystal samples at three times this damage level indicating the importance of grain boundaries in the radiation induced electrical degradation (RIED) process. Results from Rutherford Backscattering Spectroscopy (RBS) confirm that radiation enhanced diffusion of the gold contact is responsible for the degradation observed in polycrystalline alumina. copyright 1996 American Institute of Physics