Space charge accumulation and degradation in electron beam irradiated dielectrics for spacecraft

Effect of electron beam irradiation on dielectric properties in various insulating materials for spacecraft is investigated using PEA (Pulsed Electro-Acoustic) method. In space environment, spacecraft is exposed to plasma or radioactive-rays. In such condition, multilayer insulating materials covering the spacecraft are charged up. Sometimes the charge accumulation causes to the serious damage to the electric devices and degradation of insulating materials. To investigate the change of the electrical properties of dielectrics by electron beam irradiation, we measure the space charge distributions and the conduction current in some e-beam irradiated materials under dc stress. From the measurement results, it was found that the large amount of charges accumulated in some irradiated materials under dc stress, while almost no charges accumulated in the non-irradiated materials under the same stress.