Constant hole schubweg in teflon FEP (fluorinated ethylene propylene copolymer).

The hole schubweg (distance travelled between deep trapping events) in Teflon FEP (fluorinated ethylene propylene copolymer) is determined by measuring the mean depth of charge injected from the polymer surface, with various fields applied to the sample. It is found that the mean-depth of the injected charge after deep trapping is independent of the electrical field strength from 0.04 to 0.4MV/cm. The lower value of 0.04MV/cm is determined by the sensitivity of the method.