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The use of Auger spectroscopy for the in situ
elemental
characterization of sub-micrometer presolar grains.
Stadermann F. J., Floss C., Bose M., and Lea A. S. (2008)
Meteorit. Planet. Sci., 44(7), 1033-1049.
ABSTRACT
Presolar grains are small samples of stardust which can be
found at low abundances in some of the most unaltered types of
extraterrestrial materials. While earlier laboratory studies of
stardust mainly focused on grain types that can be extracted from bulk
meteorites by acid dissolution techniques, such as silicon carbide and
graphite, recent analyses of presolar silicates rely on isotope imaging
searches for locating these grains in situ. Since presolar
silicates are generally less than a micrometer in diameter and
represent at best only a few hundred ppm of their host materials (e.g.,
primitive meteorites or interplanetary dust particles), locating and
studying these particles can be analytically challenging. Recently, we
began using scanning Auger spectroscopy for the in situ
elemental characterization of presolar silicate grains as a complement
to NanoSIMS isotopic studies for obtaining spatially matched
compositional data. Auger spectroscopy is a well-established analytical
technique for elemental characterizations in the material sciences, but
has not been widely used in geological applications. We discuss the
application of this technique to sub-micrometer sized silicate grains
and address practical issues such as sample preparation, measurement
settings, spatial resolution, data processing, and elemental
quantification.
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