R5: Extraterrestrial materials

[R5-07] Nano-order chemical state analysis for H₂⁺-irradiated corundum simulating space weathering

*Yohei Igami¹, Shunsuke Muto¹, Masahiro Ohtsuka², Yuta Yamamoto¹, Aki Takigawa ³, Akira Miyake³ (1. Nagoya Univ., IMaSS, 2. Nagoya Univ., Eng., 3. Kyoto Univ., Sci.)

Keywords:corundum, space weathering, hydrogen analysis, electron microscopy/spectroscopy

We conducted H₂⁺–irradiation experiment for corundum (α-Al₂O₃) and analyzed the sample using S/TEM-EELS. TEM imaging showed dense crystal defects and nano-voids (~1 nm in diameter) from the surface to a depth of ~300 nm. Multivariate curve resolution technique for STEM-EELS spectrum imaging exhibited existence of reduced Al and hydroxyl group (OH). Similar analysis for low loss region indicated that a component with small H₂ gas peak exists. Spatial distribution of this resolved component is consistent with density distribution of the nano-voids observed by TEM observation.