skip to main content

SciTech ConnectSciTech Connect

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

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 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 x 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.
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [5] ;  [6] ;  [7] ;  [8] ;  [9] ;  [1]
  1. Hokkaido Univ., Sapporo (Japan)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Arizona State Univ., Tempe, AZ (United States)
  4. California Inst. of Technology (CalTech), Pasadena, CA (United States)
  5. National Institute for Materials Science, Ibaraki (Japan)
  6. JEOL Ltd., Tokyo (Japan)
  7. Osaka Univ., Osaka (Japan)
  8. Kyushu Univ., Fukuoka (Japan)
  9. Institute for Isotope Geology and Mineral Resources, Zurich (Switzerland)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 0016-7002
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Geochemical Journal
Additional Journal Information:
Journal Volume: 49; Journal Issue: 5; Journal ID: ISSN 0016-7002
Geochemical Society of Japan
Research Org:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Org:
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS solar wind; helium; SRIM; depth profile; NASA Genesis mission; post-ionization