Charge distribution in electron-beam irradiation polymers

The laser-induced pressure pulse (LIPP) method was used to measure charge distributions in electron-beam charged Teflon, Mylar, and Kapton as a function of charge density. One-side metallized 24 to 25 μm thick Mylar and Kapton films were charged through their nonmetallized face with 10 to 40 keV electron beams and investigated with the LIPP method. The measurements show negative space-charge layers whose depth increased with electron-beam energy and with injected charge density. In addition, positive surface- and near-surface-charge layers due to air breakdown and negative surface-charge layers caused by ohmic relaxation or by dipole effects are present on some samples