PSpice Modeling of the Pulsed Electro-acoustic Signal

Dielectric materials are frequently used in satellite structures as thermal blankets. Various aspects of the space environment can cause orbit satellite anomalies. One of these aspects is charge accumulation due to the flux of space charged particles. To get a better control of the discharge, it is necessary to clarify the nature and the time evolution of position and quantity of stored charges space and to understand the dynamics of the charge transport in solid dielectrics used in space. As dielectrics materials for space application are thin, less than 100 mu m, the current pulsed electroacoustic (PEA) method used to recover charges within this kind of material is no longer sufficiently precise, i.e. spatial resolution is on the order of ten mu m. This study aims at improving the spatial resolution of PEA technique in order to reach a resolution of about 1 mu m. To understand physical mechanisms linked to the improvement of space resolution, an electrical model of this technique has been developed using the PSpice software. The acoustic detector is specifically studied in this paper. We highlight the fact that piezoelectric losses and impedance matching between the different materials of PEA cell have a significant influence on the quality of the output voltage of this method. Moreover, an optimization algorithm is presented in order to estimate an optimized set of parameters capable of predicting the output voltage of a PEA cell.