Sputtering of lunar regolith simulant by protons and singly and multicharged Ar ions at solar wind energies

The lunar surface-exosphere connection: Measurement of secondary-ions from Apollo soils

“…We note that, although oxygen is sputtered from the surface (Meyer et al, 2011), O + ions are an insignificant fraction of the secondary ion spectrum. …”

Kinetic and potential sputtering of lunar regolith: The contribution of the heavy (minority) solar wind ions

“…[1]) to compare mass-resolved sputtering in the range 2-20 amu by 375 eV/amu protons and same velocity Ar + , Ar 6+ , and Ar 9+ ions. The Ar 6+ , and Ar 9+ ions were used as proxies for solar wind multicharged ions having neutralization energies in the range 300-1000 eV.…”

“…On the basis of preliminary measurements of H + , Ar +1 , Ar +6 and Ar +9 ion sputtering of JSC-1A lunar regolith simulant at solar wind velocities, performed at the ORNL Multicharged Ion Research Facility using quadrupole mass spectrometry [1], together with TRIM [2] simulations of kinetic sputtering yields, the relative contributions of kinetic and potential sputtering contributions are estimated. XPS analyses of simulant samples exposed to singly and multicharged Ar ions show the characteristic signature of reduced Fe, consistent with the preferential ejection of oxygen atoms expected in metal oxide potential sputtering.…”

Sputtering of Spherical SiO2Samples

“…In the solar wind, except the proton component that represents about 93% of the charged particle flux, the remaining 7% is distributed among the major solar wind heavier ions (He through Ar [11]). These heavy elements in the solar wind are usually multicharged (e.g., O 6+ and Fe 10+ ), thus their internal energy can enhance the sputtering yield of nonconducting grains by a potential sputtering mechanism [11]- [13]. This potential sputtering may significantly alter the total sputtering yield (e.g., of the lunar surface oxides) despite their low abundances relative to protons [4], [14].…”

“…However, experimental data on the yield angular dependence are rather sparse, namely, for oxides and compounds (see [17] for a review). Researchers usually rely on simulated dependences (see [6], [13], [18]), and the TRIM software package [19], [20] is frequently used for this purpose (see [21]). However, modeling approaches need knowledge of input parameters that are quite disputable for multicomponent targets.…”