TSC study of traps in electron-irradiated Teflon and polyethylene

Abstract

Thermally stimulated currents (TSC) have been measured from Teflon (PTFE) and polyethylene irradiated in vacuum with low-energy (6 keV) electrons at −180°C. The spectra from both materials are virtually identical, and consist of seven overlapping peaks. Each material contains at most three different traps in spite of the larger number of peaks. All of the trap energies and escape frequencies have been determined for PTFE and a number of them for polyethylene. The results suggest that there are different structural locations in a material for the same type of trap, and that differences in peak positions are due to different degrees of molecular motion. No peaks are observed from either material above 0°C. Previous work has shown a large number of peaks above 0°C from corona-charged specimens. This and other results show that the long-term stability of corona-charged electrets must be attributed to ion trapping rather than electron trapping.