Spatial resolution in Bragg-magnified X-ray images as determined by Fourier analysis

The spatial resolution of an imaging system is most often experimentally determined by using model objects and idealized imaging conditions. This traditional approach does not properly take into account the influence of noise and the dependence of contrast on the object. The latter influence is essential especially in the case of magnified X-ray images acquired by two fold asymmetric Bragg diffraction. For this phase sensitive technique the application of a criterion for spatial resolution based upon Fourier analysis is shown to provide reliable resolution values in a simple way, overcoming the limitations mentioned above. For the case of Bragg-magnified imaging of an ant leg with 166 fold magnification (effective pixel size 0.094 mu m), the physical resolution achieved in the image is found to be 0.4 mu m. (c) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.