Depth profiling analysis of solar wind helium collected in diamond-like carbon film from Genesis

作者：Bajo Ken ichi; Olinger Chad T; Jurewicz Amy J G; Burnett Donald S; Sakaguchi Isao; Suzuki Taku; Itose Satoru; Ishihara Morio; Uchino Kiichiro; Wieler Rainer; Yurimoto Hisayoshi^*

来源：Geochemical Journal, 2015, 49(5): 559-566.

DOI：10.2343/geochemj.2.0385

• solar wind
• depth profile
• helium
• NASA Genesis mission
• post-ionization

The distribution of solar-wind ions in Genesis mission collectors, as determined by depth profiling analysis, constrains the physics of ion-solid interactions involving the solar wind. Thus, they provide an experimental basis for revealing ancient solar activities represented by solar-wind implants in natural samples. We measured the first depth profile of He-4 in a Genesis collector; the shallow implantation (peaking at <20 nm) required us to use sputtered neutral mass spectrometry with post-photoionization by a strong field. The solar wind He fluence calculated using depth profiling is similar to 8.5 x 10(14) cm(-2). The shape of the solar wind He-4 depth profile is consistent with TRIM simulations using the observed He-4 velocity distribution during the Genesis mission. It is therefore likely that all solar-wind elements heavier than H are completely intact in this Genesis collector and, consequently, the solar particle energy distributions for each element can be calculated from their depth profiles. Ancient solar activities and space weathering of solar system objects could be quantitatively reproduced by solar particle implantation profiles.

• 出版日期2015