W0182
Powder Diffraction using a Single Crystal Diffractometer
and Area Detector for Phase Identification. Kingsley Smith, Bob He, Bruker
AXS, Inc, 5465 East Cheryl Parkway, Madison, WI 53711-5373 USA.
Sometimes, even a crystallographer needs to collect a powder
pattern on various samples or polymorphs. Samples can be: mounted single
crystals, filled capillary, or small reflection mount, depending upon the amount
of material available. Using a typical single crystal diffractometer with an
area detector, we will explore the various data collection strategies to obtain
the highest accuracy powder spectrum. Despite the collecting of multiple frames
at different 2T "swing" angles, a single composite image, analogous to the old
Debye-Scherrer film cameras, is present to the user. A single region of interest
(ROI) is selected by the user on the composite image. We will discuss the
algorithms used in converting intensities of frame pixels into a single
diffraction spectrum, particularly the "normalized bin" algorithm of accurately
converting every intensity count to the 2T spectrum and the "merge" algorithm of
combining multiple frame images into a single diffraction spectrum.