Secondary electron emission from lunar soil: Yields, energy distributions, and charging effects

•We report energy distributions of electrons ejected from lunar soil 61241 by 40–2000 eV electrons.•Total secondary electron yields are ∼1 for 40–2000 eV electrons on lunar soil 61241.•Charging with 10 keV electrons in ultrahigh vacuum showed differential charging and grain motion on the surface of lunar soil 61241.

We report the electron emission and charging of sub-mature lunar highland soil 61241 by electron impact under ultra-high vacuum for 40–2000 eV electrons. The energy distribution of emitted secondary electrons was measured as a function of primary electron energy under neutral charging conditions, and electron energy loss spectroscopy was used to determine the ∼8 eV band gap. Total electron yields were obtained with low electron fluxes. Imaging the soil with a Scanning Auger Microprobe using 10 keV electrons revealed differential grain motion induced by charging in ultra-high vacuum.