HR: 11:05h
AN: SH32A-04    [Abstracts]
TI: Analysis of Solar Wind Samples Returned by Genesis Using Laser Post Ionization Secondary Neutral Mass Spectrometry
AU: Veryovkin, I V
EM: VerIgo@anl.gov
AF: Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 United States
AU: * Calaway, W F
EM: WFCalaway@anl.gov
AF: Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 United States
AU: Tripa, C E
EM: tripa@anl.gov
AF: Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 United States
AU: Pellin, M J
EM: pellin@anl.gov
AF: Materials Science Division, Argonne National Laboratory, 9700 S. Cass Ave., Argonne, IL 60439 United States
AU: Burnett, D S
EM: burnett@gps.caltech.edu
AF: Geological and Planetary Sciences Division, California Institute of Technology, Mail Code 100-23, Pasadena, CA 91125 United States
AB: A new secondary neutral mass spectrometry (SNMS) instrument implementing laser post ionization (LPI) of ion sputtered and laser desorbed neutral species has been developed and constructed for the specific purpose of quantitative analysis of metallic elements at ultra trace levels in solar wind collector samples returned to Earth by the Genesis Discovery mission. The first LPI SNMS measurements are focusing on determining Al, Ca, Cr, and Mg in these samples. These measurements provide the first concentration and isotopic abundances determinations for several key metallic elements and also elucidate possible fractionation effects between the photosphere and the solar wind compositions. It is now documented that Genesis samples suffered surface contamination both during flight and during the breach of the Sample Return Capsule when it crashed. Since accurate quantitative analysis is compromised by sample contamination, several features have been built into the new LPI SNMS instrument to mitigate this difficulty. A normally-incident, low-energy (<500 eV) ion beam combined with a keV energy ion beam and a desorbing laser beam (both microfocused) enables dual beam analyses. The low-energy ion beam can be used to remove surface contaminant by sputtering with minimum ion beam mixing. This low-energy beam also will be used to perform ion beam milling, while either the microfocused ion or laser beam probes the solar wind elemental compositions as a function of sample depth. Because of the high depth resolution of dual beam analyses, such depth profiles clearly distinguish between surface contaminants and solar wind implanted atoms. In addition, in-situ optical and electron beam imaging for observing and avoiding particulates and scratches on solar wind sample surfaces is incorporated in the new LPI SNMS instrument to further reduce quantification problems. The current status of instrument tests and analyses will be presented. This work is supported by the U. S. Department of Energy, BES-Materials Sciences, under Contract W-31-109-ENG-38, and by NASA under Work Orders W-19,895 and W-10,091.
DE: 1027 Composition of the planets
DE: 1060 Planetary geochemistry (5405, 5410, 5704, 5709, 6005, 6008)
DE: 2164 Solar wind plasma
DE: 2169 Solar wind sources
DE: 2194 Instruments and techniques
SC: SPA-Solar and Heliospheric Physics [SH]
MN: Fall Meeting 2005