Subsections

Get X-ray PDF

The top frame of the GUI shows some general settings, as explained in Table 3.2. Please refer to Table 3 for the column descriptions in all tables.

**Table 3.9:** Descriptions of the GUI top frame of Get X-ray PDF
$\begin{table}\centering \begin{tabularx}{\textwidth}{\vert r\vert l\vert X\vert}... ...ing up a GUI to select working directory \\ \hline \end{tabularx} \end{table}$

Input data files

You can specify the file format by clicking on the Customize... button. Please see Appendix B for all supported file formats. It should be straightforward to load data and background files. One restriction is that the four kinds of file (sample, sample background, container, container background) must have exactly the same format, but can have different number of data points. In the case of multiple scans in SPEC format, each scan is considered as the merged data for one detector. Data from more than one detectors will be blended together to get I(Q). For each detector, some degrees of freedom is provided for both sample and background data. Table 3.2.1 shows the descriptions, noting that they only become editable after data files are read successfully (by clicking on the Get I(Q) button).

**Table 3.10:** Descriptions of the GUI to input and edit data files
$\begin{table}\centering \begin{tabularx}{\textwidth}{\vert r\vert l\vert X\vert}... ...m, but applied to different data type \\ \par\hline \end{tabularx} \end{table}$

Experimental setup

In this section, X-ray wavelength and polarization factor can be selected from some predefined values, or entered manually when choosing type as Customize .... In case of non-polarized X-ray (in-house source), you will be asked to input the monochromator information, such as the crystal type, where it's positioned, and the d-spacing of the reflection plane used.

The absorption coefficient of the container only becomes important when it's large. When a filter is used after the sample (either to suppress the fluorescence or Compton contributions), the absorption of the filter is needed if elastic scattering is also significantly attenuated. Others are optional, mostly for the purpose of keeping a good record.

Sample information

**Table 3.11:** Descriptions of the GUI to set up sample information
$\begin{table}\centering \begin{tabularx}{\textwidth}{\vert r\vert l\vert X\vert}... ...he estimated $\mu$t here (not editable) \\ \hline \end{tabularx} \end{table}$

In this section, you need to input the chemical compositions of your sample. First thing you need to do is to specify the elements. See Table 3.2.3 for details.

**Table 3.12:** Descriptions of the GUI to set up S(Q) corrections (I)
$\begin{table}\centering \begin{tabularx}{\textwidth}{\vert r\vert l\vert X\vert}... ...less the polarization factor is 1.0. \\ \par\hline \end{tabularx} \end{table}$

**Table 3.13:** Descriptions of the GUI to set up S(Q) corrections (II)
$\begin{table}\centering \begin{tabularx}{\textwidth}{\vert r\vert l\vert X\vert}... ...the same data into a file you select \\ \par\hline \end{tabularx} \end{table}$

S(Q) corrections set up

This GUI section tells the program what corrections to apply, as well as some parameter values. It's not as complicated as it may look like. At this moment, only the Generic correction method is implemented. So keep it set all the time. For all other corrections, please see Table 3.2.3 and 3.2.3.

G(r) set up

Under the GUI section of G(r) Optimization, what's of most interest is the range of S(Q) to use and the range of G(r) to generate. It should be straightforward to input those values. In particular, Qgrid of 0.0 means all Q values in the data will be used (either regular or irregular).

Data visualization and actions

Data visualization has bee described in details in Section 2.4.9. Data processing is triggered by the row of buttons near the bottom. What they do is explained in Table 3.2.6.

**Table 3.14:** Descriptions of the GUI to visualize data and process data
$\begin{table}\centering \begin{tabularx}{\textwidth}{\vert r\vert l\vert X\vert}... ...the same data into a file you select \\ \par\hline \end{tabularx} \end{table}$

The last row of the GUI is User Message, which displays some information during the data processing, as well as warning or error messages. When running on Linux/UNIX platforms, the program also writes messages to the terminal.

Xiangyun Qiu 2004-04-23