Proceedings of the 12th International Spacecraft Charging and Technology Conference
The range of temperature measurements have been significantly extended for an existing space environment simulation test chamber used in the study of electron emission, sample charging and discharge, electrostatic discharge and arcing, electron transport, and luminescence of spacecraft materials. This was accomplished by incorporating a new twostage, closed-cycle helium cryostat which has an extended sample temperature range from 40 K to 450 K, with long-term controlled stability of 0.5 K. The system was designed to maintain compatibility with an existing ultrahigh vacuum chamber (base pressure 10-7 Pa) that can simulate diverse space environments. These existing capabilities include controllable vacuum and ambient neutral gases conditions (10-8 to 10-1 Pa), electron fluxes (5 eV to 30 keV monoenergetic, focused, pulsed sources over 10-4 to 1010 nA-cm-2), ion fluxes (0.1 to 5 keV monoenergetic sources for inert and reactive gases with pulsing capabilities), and photon irradiation (numerous continuous and pulsed monochromated and broad band IR/VIS/UV [0.5 to 7 eV] sources). The new sample mount accommodates 1 to 4 samples of 1 cm to 2.5 cm diameter in a low temperature carousel, which allows rapid sample exchange and controlled exposure of the individual samples. Custom hemispherical grid retarding field analyzer and Faraday cup detectors, custom high speed, high sensitivity electronics, and charge neutralization capabilities used with 50 pA, 5 us, 3103 electrons/pulse pulsed beam sources permit high-accuracy electron emission measurements of extreme insulators with minimal charging effects. In situ monitoring of surface voltage, arcing, and luminescence (250 nm to 5000 nm) have recently been added.
Dekany, Justin; Johnson, Robert H.; Wilson, Gregory; Evans, Amberly; and Dennison, John R., "Ultrahigh Vacuum Cryostat System for Extended Low Temperature Space Environment Testing" (2012). All Physics Faculty Publications. Paper 1455.