T. Salditt et al., X-RAY COHERENCE AND ULTRA-SMALL ANGLE RESOLUTION AT GRAZING-INCIDENCEAND EXIT ANGLES, Zeitschrift fur Physik. B, Condensed matter, 96(2), 1994, pp. 227-230
We measure the nonspecular x-ray scattering at grazing incidence and e
xit angles from a GaAs surface, modulated by an one-dimensional latera
l grating of effectively variable periodicity 1 mu m less than or equa
l to d less than or equal to 60 mu m. Due to the projection onto the s
ample surface, the lateral coherence length is enlarged by a factor of
more than 100. The line broadening of the diffraction maxima is used
to deduce the number of periods that add up coherently for a given per
iod d and given angle of incidence. We demonstrate that the scattering
geometry used allows for large coherently illuminated lengths on the
sample and ultra small angle resolution of one- or two-dimensional obj
ects. Thus structures of mu m size and larger will be accessible by co
herent x-ray scattering.