Link to NIST Center for Neutron Research home page Link to National Institute of Standards & Technology home page
Link to Tcl/Tk information


EXPGUI top Next page Previous page

EXPGUI, part 3

A.3 Histogram pane

The histogram pane is used to edit background and diffractometer constants for a histogram, as well as set damping and refinement flags for these parameters.

If "Multiple Histogram Selection" mode is set to "All", this pane is disabled. For other settings of this mode, groups of histograms can be selected and modified collectively.

If the EXPTOOL program (see the installation instructions) is installed, a button for adding histograms will appear on the bottom right on this pane, as seen below. If the program is not properly installed, no errors occur, but the button does not appear.

Note that the order that histograms appear in this pane is determined by the "Sort histograms by" option in the Options Menu.

EXPGUI Screen snapshot

If there is more than one phase present in the refinement, an extra box appears at the top of the pane to allow phase flags to be selected. This allows a phase to be used in some histograms but not in others. It also offers a simple way to effectively "delete" a phase by removing it from all histograms. Be sure to rerun POWPREF after changing the phase flags.
EXPGUI Screen snapshot

The pane appears slightly differently when "Multiple Histogram Selection" mode is set to a single histogram type. In this case diffractometer constants are edited in separate windows (see Global Editing of Parameters, below).

EXPGUI Screen snapshot

A.3.1 Editing background

EXPGUI Screen snapshot When the button labeled "Edit Background", (or "Globally Edit Background" or in the case where "Multiple Histogram Selection" mode is set to a single histogram type) is pressed, a window such as the one to the left is displayed. In the case where background coefficients are being edited for more than one histogram ( "Multiple Histogram Selection" mode must be set to a single histogram type) the entry boxes will appear blank and only those terms that are filled in will be changed when the "Set" button is pressed. This option is mostly useful when changing the background function or the number of terms for several histograms at a single time. Note that no changes are made until the "Set" button is pressed.

A.3.2 Global Editing of Parameters

EXPGUI Screen snapshot The dialog to the left shows how a difractometer constant can be edited for more than one histogram ( "Multiple Histogram Selection" mode must be set to a single histogram type). This menu is also used to globally set the Phase Fraction.

A.3.3 Entering New Diffractograms

EXPGUI Screen snapshot Pressing the "Add New Histogram" button creates the dialog to the left. A data file and an instrument parameter file are selected using the "Select File" buttons. If more than one bank is defined, the bank must be selected and the maximum data value to be considered, must be entered. Note that the units for the maximum (minimum for d-spaces) must also be selected. To view a data file, to see the extent of the data, the "Run RAWPLOT" button may be used. Note that EXPGUI cannot communicate the names of the data and instrument parameter files to RAWPLOT, so they must be reentered.

If errors are detected in the input, an error message is displayed detailing where the errors are found. Otherwise, the EXPTOOL program is run. and the output is displayed


EXPGUI top Next page Previous page
Brian Toby (Brian.Toby@NIST.GOV)
$Revision: 333 $ $Date: 2009-12-04 23:04:18 +0000 (Fri, 04 Dec 2009) $