Thermal pulse method with an applied field

Based on conventional thermal pulse method, a space charge measuring system that can be used with applied voltage is presented in this study. Compared to the traditional thermal method for space charge and polarization profiles measurement, the thermal pulse method with applied voltage brings the advantages of easy calibration and the monitor of space charge dynamics under applied field. The principle of the calibration is presented based on the scale-transformation method. The influence of the applied voltage circuit within the measuring system on the thermal response current of the sample to the thermal excitation was discussed. The samples used in this investigation were commercially available biaxially oriented polypropylene (BOPP) film. The thermal pulse was generated by pulse laser with short pulse width 18ns. The results show the newly improved thermal pulse is successful to be used for space charge measurement in thin films.