# DELIA (Dispersive Exafs caLIbration and Analysis)

## Module characteristics

- Goal: To perform operations over a bunch of spectra. Operations: calibration the spectra, extraction of the XAFS signal and Fourier (and back-Fourier) filtering. This applications has been designed for the particular needs of the ESRF/ID24 beamline. The Dispersive XAFS and Turbo-XAS techniques generate a huge amount of XAFS spectra in few seconds or minutes. This module allows the user to visualize the spectra, calibrate them, extract the XAFS signal and perform Fourier and back-Fourier transforms simultaneously over all the spectra by simply point-and-click.
- Input: a file with raw data. Two possible ways of input data:

- CCD File

- ASCII: an ASCII file with a title, and an spectrum per line, the first number is the index and then the channels. Example:
  :log(I0/sample
  0 -0.602633 -0.676992 -0.650588 ........... -0.686716 -0.650588
  1 -1.287139 -1.292275 -1.289845 ............-1.287207 -1.286393
  ..............
  1500 -0.504617 -0.503630 -0.503203.......-0.490741 -0.490417
- An ESRF Data File with the spectral data.

- Sequential File:

- ASCII: a multicolumn file containing at least three columns (more columns also accepted) with X,Mu and index. The index can be any value that identify the spectrum. Usually indices are 0,1,2..., but can be, for example, a temperature value, etc.
- Binary: file that contains three columns with X,Mu and Index, all floats, written in binary format by a big endian system. The file size is then number_of_points*3*8 bits. Note that you can run DELIA in both little or big endian systems, but the file must be written by a big endian system (or also by a little endian system but swapping the byte ordering).

- Output: The results of the operations performed with DELIA can be saved using the menu File->Export CCD file. Note also that many graphical applications used for visualization also allows writing data in a number of different formats.

## Example of use

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. You may use the buton for loading an example data.
   You may export one of them for calibration.
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 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, press the 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 or exported using the "Plot results" buttons.
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. The parameters of the extraction are copied automatically to their respective boxes.
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.