Determination of temperature distribution in single- and double-side metallized electret films

The well-known thermal-pulse technique is based on the temporal change of the temperature distribution in an electret sample. The resulting nonuniform thermal expansion in the sample volume leads to an electrical signal that contains information on the charge or polarization profile. A new method is proposed in which known charge profiles (e.g., electron-beam-deposited charge layers) serve as probes for the temperature distribution as it develops after heat-pulse excitation of one of the sample electrodes. The principle of operation is described for both single- and double-side metalized samples, and first experiments on electron-beam-charged Teflon fluoroethylenepropylene films are reported