Module DELIA (Dispersive Exafs caLIbration and Analysis)

Module characteristics

Follow the steps

The DELIA analysis is done in four main steps, Each step is implemented in a different panel in the main window: Raw, mu(E), chi(k) and Fourier. You should pass from one panel to the next one after completing the operations in the current one. The names are self explanatory:

  1. Phase I [Raw]: allows to read raw data, visualize the individual spectra, overplot them. The user must identify the columns with X, Mu and indices. Using the ASCII raw sample file f29 I obtained the sample window 1.
  2. Phase II [mu(E)]: Interpolation and Calibration. It allows the user to input the parameters. Default parameters for the interpolation limits are presented. The minimum correspond to maximum value between all the abscissas spectra minima, and the maximum corresponds to the minimum between all abscissas maxima. They may be changed by the user. The user should also supply the calibrating coefficients a,b,c. By using the Get... button, the XAID_CALIB application is started to help in finding the coefficients. The coefficients found in this way are automatically transferred to the DELIA window. Once all parameters are filled, predd the RUN interpolate & calibrate button to make calculations over all spectra. The results appear in the "Result:" text window and also in a newly created XPlot window. The results can be visualized using the 2D and 3D buttons.
    If you want to create a file for further use with DELIA, press the 2D button, and from the XPLot window, select File->Write ASCII file with current set..., select then Data to save: All columns and Include header (SPEC type): No. The resulting file can then be loaded using the DELIA File->Load file with Mu(E)... menu. Some example windows are in windows 2 and 3.
  3. Phase III [chi(k)]: extraction of the XAFS signal, i.e., calculate Chi(k) from Mu(Energy) over all the spectra. For selecting the appropriate parameters for the extraction, the user must perform interactively the extraction on a single spectrum (select its index and then press the Go button to start XAID_MU2CHI module (remember to perform the extraction in k space). The parameters of the extraction are copied automatically to their respective boxes. The results can be visualized in 2D or 3D and saved to a file for further use in DELIA as shown in Phase II. See examples in windows 4 and 5.
  4. Phase IV [Fourier]: Fourier transform and filtering. As in the previous phase, the user must first perform the Fourier Filtering on a single Chi(k) spectrum, by using the XAID_FF module. The parameters are copied automatically. A sample can be found in window 6 and

FAQs

Window examples

Window 1. Main panel after loading the ASCII raw data file f29.


Window 2. Main panel after interpolation and calibration (Phase II).


Window 3. XPlot window after interpolation and calibration (Phase II).
(Click on the image for full resolution.)


Window 4. Main DELIA window during XAFS extraction (Phase III).


Window 5. XPlot window after XAFS extraction (Phase III).
(Click on the image for full resolution.)


Window 5. Main DELIA window during Fourier Filtering (Phase IV).


Acknowledgement

Thanks to the ID24 staff for providing me with the example data.



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