Deutsche Tagung f ¨ur Forschung mit ... - SNI-Portal

Methoden und Instrumentierung Poster: Mi., 14:00–16:30 M-P62
Current state of diffraction data analysis software at beamline F1, Hasylab/DESY
Carsten Paulmann 1 , Thomas Malcherek 1
1 Mineralogisch-Petrographisches Institut, Grindelallee 48, 20146 Hamburg, Germany
Since spring 2005 the beamlines F1 and D3 at Hasylab/DESY are equipped with new
Marresearch GmbH CCD detectors with an active diameter of 165 mm and a resolution
of 2048x2048 pixels (2x2 binning).
The combination of bright X-ray sources with 2D area detector systems not only allows
fast Bragg data collections (eg. charge density studies) but also greatly facilitates
studies of disordered crystals which may show weak diffuse scattering ranging from
broad and structured intensity up to weak commensurate or incommensurate satellite
reflections. Currently indexing, integration and correction of the single crystal diffraction
data collected at F1/D3 is based on the XDS package [1] which is mainly tailored
for the evaluation of standard Bragg data collections on well-ordered samples.
Analysis of diffraction data from disordered samples requires more advanced data processing
and visualisation features covering non-integer indexed positions in reciprocal
space (modulated structures, twinning) as well as a complete pixel-wise data processing
in case of short-range ordered samples exhibiting broad diffuse scattering.
To aid this process a range of software tools (C, F90, Perl) has been developed which
provides advanced possibilities of viewing and processing CCD-based diffraction data
of disordered samples. The tools include scripts to view individual image frames,
to overlay a spot prediction based on the orientation matrix obtained by XDS or to
search for the position of particular diffraction positions in a sequence of rotation
frames. Furthermore, special emphasis has been put on possibilities for a post data
collection processing (scaling, binning, data format conversion, averaging, background
subtraction). Another set of software tools aims at the reciprocal space reconstruction
from raw image data with interfaces to different common data formats (ASCII, Igor,
Kuplot). This set is currently tailored to MarCCD/XDS data but an extension to
other experimental setups (eg. Bruker-Nonius) is in progress.
All programs are mainly command line driven in order to allow for simple generation
of automated scripts and cross-network use.
[1] W. Kabsch, J. Appl. Cryst. 26 (1993) 795