Noble gas mass-spectrometry for extraterrestrial micro-samples: analyses of asteroid matter returned by Hayabusa2 JAXA mission

Mass spectrometry of noble gas isotopes extracted from limited amounts of extraterrestrial materials delivered by robotic space missions requires high sensitivity, high ion transmission, low detection limit, and several other characteristics not readily available in commercial instruments. We compared two different configurations of electron impact ionisation. We concluded that the ion source with cylindrical symmetry and without a magnetic field in the ionisation region is better for analyzing all stable noble gas isotopes extracted from sub-milligram extraterrestrial samples. Isotopic analyses of noble gases retrieved using multi-step heating of sub-mg samples delivered from near-Earth (162 173) asteroid Ryugu support this conclusion. Mass spectrometry of noble gas isotopes from the asteroid materials delivered by robotic space missions requires high sensitivity, high ion transmission, low detection limit, and other characteristics not readily available in commercial instruments.