open access

https://hdl.handle.net/2115/59846

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

英語

post-ionization

2015

The Geochemical Society of Japan

Geochemical Journal

49(5)

559-566

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 4He 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 ~8.5 × 1014 cm-2. The shape of the solar wind 4He depth profile is consistent with TRIM simulations using the observed 4He 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.

学術雑誌論文

Version of Record

0016-7002

1880-5973