PEA System Modeling and Signal Processing for Measurement of Volume Charge Distributions in Thin Dielectric Films

This paper discusses an effort to develop advanced pulsed electroacoustic (PEA) measurement system capabilities that incorporate state-of-the-art hardware and improved signal processing and modeling to characterize embedded charge distributions in thin dielectric films. Objectives in developing this system include: (1) improved spatial resolution, while maintaining reasonable temporal resolution; (2) improved signal processing tools for increased signal/noise ratios; (3) integrated PEA modeling tools; and (4) integrated environmental controls. We emphasize system improvements required to achieve high spatial resolution for in vacuo measurements of thin dielectrics charged using electron beam injection, which are most applicable for spacecraft charging tests. PEA measurement systems provide an important tool to investigate the spatial extent and dynamic evolution of such embedded charge distributions in thin dielectric materials. This knowledge has important applications in spacecraft industries, as well as for semiconductors, high-power electronic devices, high-voltage DC power cable insulation, and high-energy and plasma physics apparatus. Charge is introduced into spacecraft materials through electron beam or high energy plasma injection, and can accumulate in dielectric materials until potentials are high enough to initiate electrostatic discharge, which can lead to damage and diminished capacity of expensive and critical space assets. Knowing how, where, and how much charge accumulates and how it redistributes and dissipates can predict destructive charging effects which are recognized as a significant threat to asset survivability and mission success and have led to billions of dollars of losses