演題概要

2P-19

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太陽風起源ヘリウム同位体イメージング法の開発

(¹北大・ ²物材研・ ³JEOL・ ⁴阪大・ ⁵九大)
^o馬上謙一¹・ 川﨑教行¹・ 坂口勲²・ 鈴木拓²・ 糸瀬悟³・ 松谷幸³・ 石原盛男⁴・ 内野喜一郎⁵・ 圦本尚義¹

Isotope imaging is commonly used to investigate the localization of trace elements and their isotopes. In situ noble gas analysis of meteorites revealed the distribution of primordial noble gases that were trapped in the building blocks of asteroids and planets during the early stage of the Solar System. Solar wind noble gases are among the primordial gases present in meteorites and were trapped through exposure to solar wind. High spatial resolution in-situ noble gas analysis is crucial for identifying the carrier phase of the solar wind noble gases. We have developed ⁴He isotope imaging utilizing secondary neutral mass spectrometry with strong field post-ionization. This technique achieved a lateral resolution of 2 µm and a 4He detection limit of 2 x 10¹⁷ cm^–3. This development allows for the study of ⁴He incorporation in the solar wind gas-rich meteorite, Northwest Africa 801 carbonaceous chondrite, with micrometer-resolution.