IUCr journals

Development of new apertures for coherent X-ray experiments

J. Synchrotron Rad. (2009). 16, 358–367 (doi.org/10.1107/S0909049509003720)

[Fraunhofer diffraction patterns] Fraunhofer diffraction patterns in the horizontal (bottom) and vertical direction (top, multiplied by 10) of a 6 mm x 6 mm novel GaAs aperture generated with partially coherent 3.1 keV X-rays. The solid lines are least-squares fit of the model presented. Note that refraction effects cause the second order fringes to be more intense than the first order ones.
In a coherent X-ray scattering experiment at synchrotron sources, the incident beam must be spatially filtered by slits on a length scale smaller than the transverse coherence length of the source (10–100 μm). The Fraunhofer diffraction pattern of the slit is an important source of background in these experiments. This paper shows how one might reduce the diffracted intensity in the tail of the diffraction pattern by making slit edges softened by partial X-ray transmission using a method in visible optics called apodization.

E.M. Dufresne, S.B. Dierker, Z. Yin and L. Berman