Open circuit TSD method and anomalous air gap current in Teflon FEP

The paper shows an extension in the technique of thermally stimulated discharge in open circuit (TSD) consisting in simultaneously measuring the current and its charge on the external circuit as a function of temperature. With it, we were able to show that the noise usually appearing in the current curve of negatively charged Teflon FEP is due to microbreakdown events in the sample. Moreover, we detected the ejection of positive charges out the surface of virgin uncharged FEP samples, when a positive bias voltage was applied in the measuring circuit.