Laboratory Analysis of Neutral and Ion Sputtering of Lunar Soils
Abstract
Solar system bodies that lack a significant atmosphere do have surface bounded exospheres comprising of populations from distinct sources. These include evolved gases from planetary interiors (e.g. radionuclides such as 40Ar from the decay of 40K), sputtering from the solar wind and micrometeorite impacts, electron and photon desorption processes, and thermal reemission from the surface of exospheric volatiles. These populations exhibit differing thermal properties and since exospheric particles do not undergo collisions, this non-interaction serves to preserve information on the particle's sources and energetics. Thus, the study of exospheres yields global and regional information on their sources including surface composition, the processes that create them, and it reveals information on the transport of volatiles.
Data from surface bounded exospheres are limited, needing laboratory measurements to support interpretation, especially as it pertains to separating the distinct exospheric sources in the in-situ data. To this end we describe progress on laboratory experiments to determine the energetics of sputtering from lunar regolith samples and simulants. An ion beam designed to simulate the solar wind is directed toward lunar samples under ultra-high vacuum. Using a pulsed beam to effect sputtering and through phased extraction of the sputtered particles we determine their composition and velocity distribution. We will compare ion sputtering yields and velocity distribution from primary ions Ar+ and H2+ from 1 amu to ~100 amu from target JSC1a and lunar soil 76055. The sample, 76055 is a vesicular breccia soil collected during Apollo 17. In this presentation we will discuss the experiment, preliminary results and implications for interpreting astronomical observations and orbital data.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P31C3483K
- Keywords:
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- 6205 Asteroids;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6230 Martian satellites;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6250 Moon;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS