[Ifeffit] Possible bug in Athena during alignment
L.Clarke at mmu.ac.uk
Wed Oct 15 09:21:39 CDT 2014
I'd like to report a possible bug within Athena.
Last week I collected Br K-edge data at the APS and have experienced an issue with Athena during data alignment. The beamline energy required calibration and so I did the following data processing steps, in this order:
1. Completed pre- and post-edge corrections, using windows relative to the actual Br K-edge energy, on the raw data exported from the beamline. (In other words these windows were not energy offsets relative to the actual measured edge position).
2. Used the flatten post-edge feature within Athena.
3. 'Calibrated' (Normalised is a better term really) the first derivative of a NaBr measurement to the Br K-edge energy using the calibrate drop-down option. This resulted in the requirement for a -17.39 eV energy offset.
4. Tried to align all of the sample data to the NaBr 'standard' using the align drop-down option.
The issue I have had is with step #4. When I aligned, for several samples the XAFS (XANES) plots went wrong. It seems that Athena was not transforming the pre- and post-edge windows correctly for such a large energy shift, i.e. didn't shift these to lower energies by 17.39 eV, and I think this is a bug within Athena.
I hope the above makes sense; I can provide an Athena project file, if required.
Many thanks, Leon
Dr Leon J. Clarke
Senior Lecturer in Environmental Analytical Chemistry
Division of Chemistry and Environmental Sciences
School of Science and the Environment
Faculty of Science and Engineering
Manchester Metropolitan University
John Dalton East
E-mail: l.clarke at mmu.ac.uk<mailto:l.clarke at mmu.ac.uk>
Tel: +44 (0)161 247 1412
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