Quantitative chemical mapping in 3-d by STXM tomography

WHO:  Adam Hitchcock, Göran Johansson, BIMR, McMaster University;  
            Gary Mitchell, Melinda Keefe, Dow Chemical, Midland, MI
             Tolek Tyliszczak, Advanced Light Source, Berkeley Lab, Berkeley, CA 94720 USA
 
WHERE:  Advanced Light Source  BL 5.3.2  Scanning Transmission X-ray Microscope (STXM)
 
WHEN:   Jan-June 2007               POSTED:  19 November 2007

WHAT:  An apparatus to allow rotation of samples at the focus of the X-ray beam in scanning transmission X-ray microscopy has been developed and used to measure three-dimensional chemical distributions with ~50 nm spatial resolution in 3-d. The sample is polymer latex microspheres in water, with each ~1 micron diameter polystyrene sphere enclosing low density polyacrylate (~2 wt-% of the solid). By measuring at 2 photon energies, the difference signal maps the acrylate. The first movie shows a fly through of a rendering of the quantitative 3-d chemical mapping of the whole system, with the water removed. The second movie isolates the signal from the acrylate and displays its 3-d distribution using green for more dense and blue for less dense voxels. This informaiton is useful to Dow chemists optimizing the acrylate filling of these microspheres, for use as a high performance coating component.

REFERENCE: G.A. Johansson, T. Tyliszczak, G.E. Mitchell, M. Keefe and A. P. Hitchcock, Three dimensional chemical mapping by scanning transmission X-ray spectromicroscopy, J. Synchrotron Radiation 14 (2007) 395-402