Quantitative measurements of total yields from electron stimulated desorption of ice

Sputtering yields from electron stimulated desorption (ESD) are typically neglected by planetary science models, although mid-energy (200-1000eV) electrons can produce significant sputtering yields. Here, we investigated the total and relative yields from ESD on comet ice analogs in an Ultra-High Vacuum (UHV) chamber with base pressure of 3x10^-11 torr. Gas was introduced to the chamber, then condensed on a sample holder, which was then irradiated with an electron source at various energies. A quartz-crystal microbalance (QCM) was used for precise mass desorption measurements, while a quadrupole mass spectrometer (QMS) was used to measure the positive, negative and neutral species that desorbed off the ice. These processes are relevant for various planetary science environments which are subjected to high intensity of electron bombardment, such as the rings of Saturn, Icy Moons, and interstellar ices. The results of our experiments will provide more accurate yields for modeling sputtering from airless bodies.