Large Area and High Resolution Mapping and Spectral Imaging

Maximum Possible Information on the Nature of a Sample

Identification of trace elements and corresponding phases with hyperspectral imaging (ESPRIT HyperMap)

Comparing Sum Spectrum and MaximumPixelSpectrum
Comparing sum (blue) and MaximumPixel-
Spectra (red) of a granite section.
Several rare earth elements could be
determined in the sample

Determining traces of elements in a sample is an important task in EDS. Elements present are normally searched in a sum spectrum. Nevertheless, this is somewhat error-prone, as elements present in a few locations only may be averaged out and so overlooked. The MaximumPixelSpectrum function available for ESPRIT HyperMap helps to avoid this by synthesizing a spectrum containing the highest count level of each channel of each spectrum in the HyperMap. The figure above compares sum spectrum and MaximumPixelSpectrum.

Using the information gained from the MaximumPixelSpectrum found elements can easily be made visible in the element map. The sample analyzed was a polished granite section containing very few monazite particles. It could for instance be shown that cerium is present in five small isolated particles distributed over the mapped area.

Download the corresponding application note #04 (PDF)

 

High resolution mapping of an oceanic drill core

Oceanic Drill Core Map
Map (original size 3072 x 4096 pixels)
showing the uppermost layer of ejecta
in the oceanic drill core ODP Leg 207,
discernible by the orange tinted
layer. Note that the carbonates (light
and dark blue particles) and quartz
(purple) are restricted

A large area and high resolution mapping allows to gain an overview and to see details of a sample in a single map. The specimen analyzed was a piece of an oceanic drill core containing ejecta from the Chicxulub crater in Mexico. The meteorite that caused this crater around 65 million years ago is said to be the reason for the extinction of the dinosaurs.

A 4096 x 3072 pixel map was obtained from the ejecta layer in the specimen. Thanks to the capabilities of the XFlash® detectors the mapping could be performed in only 33 minutes, using an input count rate of 500 kcps.

The high resolution composite element map displays a distinct layer in the uppermost millimeters of the ejecta deposit. It comprises abundant calcite (CaCO3) and dolomite [(Ca,Mg)CO3] spherules, few shocked quartz (SiO2) fragments and aluminosilicate grains such as feldspar [(K,Na)AlSi3O8, NaAlSi3O8  – CaAl2Si2O8]. The dolomite spherules have irregular serrated boundaries enclosed by a layered clay shell indicating impact-induced mechanical and thermal stress during the impact event. The porous calcite spherules resemble experimentally produced degassing textures.

Download the corresponding application note #07 (PDF)

Advanced light element and low energy X-ray analysis of a TiB2-TiC-SiC ceramic material using EDS spectrum imaging

Quantitative Single Element  Maps of a Ceramic Sample
Quantitative maps of main constituents
boron (a), carbon (b), silicon (c) and
titanium (d). Major phases are identifiable
by comparing concentrations in the
individual maps. TiB<sub>2</sub>, SiC and
TiC have been labeled for reference

The sample investigated is a sintered hard ceramic material, mainly composed of titanium di-boride (TiB2), titanium carbide (TiC), silicon carbide (SiC) and a number of minor constituents. A polished but uncoated section of this material was analyzed.

The task we are looking at is quantitative light element mapping. The target was to determine chemical phase distribution in the sample. A possibility of doing this is by comparing quantitative single element maps. ESPRIT offers a lookup table to assign colors to concentration ranges coded in atomic% (weight % is also possible), as shown in the figure above. Comparing concentrations in the same ranges of the map allows to localize phases. As an aid to localize the phases in the maps according labels have been placed in the image above.

The next step would be to use ESPRIT Autophase to clearly assign phases.

Download the corresponding application note #10 (PDF)