Send, S.; Abboud, A.; Wiesner, N.; Shokr, M.; Klaus, M.; Genzel, C.; Conka-Nurdan, T.; Schlosser, D.; Huth, M.; Hartmann, R.; Strüder, L.; Pietsch, U.:
Application of a pnCCD for energy-dispersive Laue diffraction with ultra-hard X-rays. Journal of Applied Crystallography 49 (2016), p. 222 - 233
10.1107/S1600576715023997
Abstract:
In this work the spectroscopic performance of a pnCCD detector in the ultrahard
energy range between 40 and 140 keV is tested by means of an energydispersive
Laue diffraction experiment on a GaAs crystal. About 100 Bragg
peaks were collected in a single-shot exposure of the arbitrarily oriented sample
to white synchrotron radiation provided by a wiggler at BESSY II and resolved
in a large reciprocal-space volume. The positions and energies of individual
Laue spots could be determined with a spatial accuracy of less than one pixel
and a relative energy resolution better than 1%. In this way the unit-cell
parameters of GaAs were extracted with an accuracy of 0.5%, allowing for a
complete indexing of the recorded Laue pattern. Despite the low quantum
efficiency of the pnCCD (below 7%), experimental structure factors could be
obtained from the three-dimensional data sets, taking into account photoelectric
absorption as well as Compton scattering processes inside the detector. The
agreement between measured and theoretical kinematical structure factors
calculated from the known crystal structure is of the order of 10%. The results of
this experiment demonstrate the potential of pnCCD detectors for applications
in X-ray structure analysis using the complete energy spectrum of synchrotron
radiation.