The POWDER DIFFRACTION (2-D) interface allows Debye-Scherrer
rings which have been recorded of a 2-D detector to be integrated
to the equivalent of a 2-theta scan with a zero-dimensional detector
[10].
An example of an input image and the main menu are shown in
Figure 32, Page .
To aid with this the MASK sub-menu allows interactive definition
of masked areas i.e. pixels which will be ignored during further
operations. The TILT button allows the beam centre and
any non-orthogonality of the detector to the main beam to be refined,
and this tilt is used by the INTEGRATE command. Other types
of output are also available. The CAKE sub-menu allows different
regions of the image to be defined with graphical coordinate input for
the starting azimuth, end azimuth and inner and outer radii of the
integrated region. The number of output bins in both the azimuthal and
the 2-theta or radial direction are user specified. This allows a
variety of different output possibilities e.g. A number of different
2-theta scans, for different azimuth ranges; a 1-D profile of intensity
of a ring as a function of azimuth (e.g. for texture studies); or
a polar transform of the data. The output formats include one of the
GSAS formats [15], one of the
Cerius formats9, and a general purpose ASCII two column format, which
may easily be edited.
The POWDER DIFFRACTION (2-D) Main Menu contains the following commands: