Volume Charge Distribution Measurement in Thin Dielectrics

ABSTRACT: Over half of spacecraft system anomalies attributed to interactions with the natural space environmentincluding electron upsets, damage to components, power system debilities, and complete satellite failuresare attributed to spacecraft charging. While measurements of electron emission, surface potential and electrostatic breakdown provide important information, the"holy grail"of materials characterization in spacecraft charging is a nondestructive method which directly measures the magnitude, spatial distribution, and temporal evolution of internal charge appropriate to practical spacecraft charging problems. Pulsed electro-acoustic (PEA) measurements are potentially such a method. Active spacecraft charging groups with PEA capabilities exist only outside the US. Spacecraft environment fluxes are typically dominated by low energy particles with penetration depths into dielectric materials<2m, which is less than the resolution of current PEA methods. Box Elder Innovations"Phase I effort will determine feasibility of increasing spatial charge distribution resolution to ~1m, while maintaining or improving current temporal resolution and charge sensitivity. Phase II will develop an instrument to measure time evolution and charge density distributions on<1m length scales. In total, the project should result in a quantum leap in charge density distribution characterization to support the prediction, avoidance and mitigation of destructive effects of charging on spacecraft. BENEFIT: Potential applications include 1) spacecraft charging 2) high voltage transmission line insulation characterization and design, 3) electrostatic breakdown in high voltage devices, and 4) high field breakdown in semiconductor materials/devices and solar arrays. Potential markets exist for each of these applications for measurement systems developed in Phase II of this program.