Proceedings of the 12th International Spacecraft Charging and Technology Conference
New instrumentation has been developed for non-contact, in vacuo measurements of the electron beam-induced surface voltage as a function of time and position for non-conductive spacecraft materials in a simulated space environment. Used in conjunction with the capabilities of an existing ultrahigh vacuum electron emission analysis chamber, the new instrumentation facilitates measurements of charge accumulation, bulk resistivity, effects of charge depletion and accumulation on yield measurements, electron induced electrostatic breakdown potentials, radiation induced conductivity effects, and the radial dispersion of surface voltage. The novel system uses two movable capacitive sensor electrodes that can be swept across the sample to measure surface charge distributions on samples, using a non-contact method that does not dissipate sample charge. Design details, calibration and characterization measurements of the system are presented, for a surface voltage range from <1 V to >30 kV, voltage resolution <1 V, and spatial resolution <1.5 mm. Extensive characterization tests with externally biased conductors were performed to calibrate the system and determine the instrument stability, sensitivity, accuracy, range, spatial resolution and temporal response.
Hodges, Joshua L.; Dennison, JR; Dekany, Justin; Wilson, Gregory; Evans, Amberly; and Sim, Alec, "In Situ Surface Voltage Measurements of Dielectrics Under Electron Beam Irradiation" (2012). All Physics Faculty Publications. Paper 1453.