Characterizing the hard x-ray diffraction properties of a GaAs linear Bragg-Fresnel lens

We investigated the diffractive focusing properties of (111) GaAs linear Br agg-Fresnel lenses (BFLs) developed for hard x-ray microscopy and microdiff raction of complex materials in confined geometries. We demonstrated that t he use of GaAs yields significant processing advantages due to the reduced zone depth. Focal plane diffraction patterns of linear BFLs measured at the advanced photon source using 8-40 keV x rays were compared to a simple mod el based on Kirchhoff-Fresnel diffraction theory. Good agreement was obtain ed between experimental data and model calculations using only zones within an effective aperture defined by the transverse coherence of the source. ( C) 2000 American Institute of Physics. [S0003-6951(00)00929-3].