Development of Signal Recovery Method in Space Charge Measurement

脉冲电声（PEA）法是研究绝缘材料中空间电荷分布的一种常用方法。通过增加声阻抗显微镜（AIM），在PEA系统中实现了样品内部空间电荷信号和声学特性信号的同时测量。利用实验组装的校准系统，成功地将PEA法的校准方法用于空间电荷测量中的声信号恢复。该方法使用PEA信号和AIM信号之间的关系。该校准系统可以解决衰减、上电极与样品声阻抗失配等问题。半导体和黄铜都被用作上电极，两种材料给出了相同的结果。因此，发现校准方法是校准所测量的PEA信号的有效手段。此外，这种校准方法不必使用半导体。

Pulsed electro-acoustic (PEA) method is widely used for space charge distribution in insulating materials. The simultaneous measurements of space charge signal and acoustic properties signal within a sample in PEA system have been assembled by adding an Acoustic-impedance microscope (AIM). By using the experimentally assembled calibration system, a calibration method for the PEA method was used successfully to recover the acoustic signal in space charge measurement. The method uses the relationship between the PEA signal and the AIM signal. The calibration system can solve problems such as attenuation, acoustic impedance mismatching between upper electrode and sample. Both a semi-conductor and brass were used as the upper electrode and both materials gave the same results. The calibration method was therefore found to be an effective means of calibrating the measured PEA signal. Furthermore this calibration method doesn't have to use the semi-conductor.