Charge Accumulation Characteristics of Fluorine Insulating Materials under Electron Beam Irradiation

Insulating materials are frequently used in spacecraft's structure and especially as thermal blanket which are protecting the electronic devices. Their behavior in relation to an electron beam irradiation due to space environment must be clearly elucidate. For example, when the electron beam is irradiated to the material, it charged up and a large electric potential difference generate between the charged and uncharged surfaces. If the difference in potential becomes very large, a discharge sometimes occurs between them. Such discharge is very harmful for the spacecraft. Therefore, at designing stage of spacecraft, it is important to understand the charging characteristics of the surface material of the spacecraft. In this paper, we focused on the charge accumulation in the materials under an irradiation of high energy electron beam. In the experiments, some fluorine materials are used which are ordinary used for the spacecraft. Judging from the measurement results, it was found that the amounts of accumulated electrons gradually decreased ever during an electron beam irradiation. In addition, we tried to explain for this phenomenon using an idea of RIC (Radiation Induced Conductivity).