Advancing Quantitative Chemical Imaging
organisation: D. Grolimund
duration: 0.5 days
X-ray microprobe techniques play an important role in quantitative chemical imaging. Most advantageous are the achievable spatial resolution, the chemical selectivity as well as the fast data acquisition speed. However, full quantitative analysis is still hampered as x-ray techniques relying on fluorescence photon detection represent matrix sensitive analytical procedures.
Proper spectrum evaluation represents the most crucial step in quantitative x-ray microprobe analysis. The analysis must address few key points such as different and complex type of continuum (background analysis and subtraction), scattering, the overlap of different elemental lines, secondary fluorescence, presence of escape and pile-up peaks, etc. With the availability of DSP detector read-out electronics, XRF scanning in full spectra mode became feasible. Accordingly, for each single pixel a full spectrum is available for quantitative analysis. Corresponding fast data processing pipelines have to be conceptualized and implemented.
Finally, in addition to chemical imaging, molecular-level analysis by means of X-ray Absorption Spectroscopy in fluorescence mode will greatly benefit by recording data in full spectra mode. The true measurement signal can more accurately be deconvolved from background and scatter contribution. A reduced noise level and higher spectrum quality would result.
The aims of the proposed workshop include:
- introduction to quantitative XRF analysis
- state of the art XRF spectrum analysis
- reliable XRF quantification based on full spectrum deconvolution
discuss/demonstrate fast, on-line data processing schemes during full spectra mode XRF imaging