Polarization of electron-beam irradiated LDPE films to understand space charge generation and transport

摘要

The implantation of electrons into insulating materials and the monitoring of the electrical response afterwards can constitute one of the ways of characterizing and modelling dielectrics. However, energetic electrons have on their own secondary effects, e.g. ionization processes that modify the response. To investigate these effects, Low Density Polyethylene (LDPE) films of different thicknesses were irradiated for 10 minutes by a 80 keV electron-beam with a current flux of 1 nA/cm2 under vacuum. Space charge measurements using the Pulsed Electro-Acoustic method were then performed in air under polarization and volt-off. The influence of the electric field polarity, amplitude, and the location of the irradiation zone as regards the electrodes are presented and discussed. Upon DC stressing, the presence of a huge amount of positive charges, due to the creation of electron/hole pairs during irradiation, is put forward.