Superposition Effects of Electron Radiation Direction on Dielectric Deep Charging Characteristics of Polyetheretherketone Dielectric

Deep dielectric charging induced by high-energy electron radiation in space environment is a key issue on the operation of the spacecraft. The insulation structure that used in roll-ring conductive rotating joint is subjected to charging, leading to insulation failure. In this paper, the deep charging characteristics of the PEEK (polyetheretherketone) dielectric in roll-ring structure by electron irradiation with an energy of 0.3 MeV and density of 5\times 10^{-7}\ \mathrm{A}/\mathrm{m}^{2} were studied. Unlike the previous work, the different radiation directions are considered in this paper. The electron beam with an angle of 0°-90° strikes the roll-ring insulation and the dielectric charging related to the superposition effects of charging are focused. A simulation model including the dielectric deep charging process and radiation induced conductivity (RIC) is conducted. The characteristics of high-energy electron charge deposition, space charge, electric field and current density are discussed. The simulation results show that the electric field distribution in the insulation structure shifts to high value with the increase in the radiation angle. When the incident angle of electron beam is higher than 45 °, the electric field at the electrode-dielectric junction point is higher than that of the electrode-dielectric-vacuum triple junction point. In this case, the discharge is likely to occur before at triple junction point.