Radiation Induced Conductivity in Teflon FEP Irradiated With Multienergetic Electron Beam

Teflon Fluorinated Ethylene Propylene (FEP), used as thermal blankets on satellites, has a specific electrical behavior under space ionizing environment. Charging behaviors of this dielectric material, under electron beam irradiation, is of special interest for future spacecraft needs. Hence, ground experimental parameters have been adjusted in order to distinguish between the different physical mechanisms that steers FEP charging potential. The effect of incident electron spectrum, electric field, and dose rate has been investigated through surface potential measurements during and after the irradiation process. The experimental results especially reveal that charging potential evolution as a function of time is not strongly dependent upon the electron spectrum and the electric field but varies noticeably with dose rate. These results have been analyzed in the light of a physical model that takes into account ionization, trapping/detrapping, and recombination mechanisms for negative and positive charges.