High-Energy Electron-Induced Discharges in Printed Circuit Boards

Experimental investigations of spacecraft charging effects produced by energetic electrons capable of penetrating the spacecraft exterior have been performed. Electron exposures of printed circuit boards have revealed relatively large discharges resulting in correspondingly large transients induced onto the PC board strips to which electronic components are directly attached. Voltages in excess of 50 volts have been measured across 50-ohm impedances. Coupled signals had rise times of 10 nsec or less and pulse widths of from 10 nsec to hundreds of nanoseconds. Spacecraft charging and discharging within spacecraft electronics appear to be a new and important aspect of the spacecraft charging problem.