Optical elements for dynamically broadening the focus of micro-focus optics at synchrotron x-ray sources

Third generation synchrotron radiation sources offer the possibility of using high demagnification ratio optics to achieve a micro-focused X-ray beam profile of size less than one micrometre size. This is highly advantageous for a variety of experiments. There is however also a requirement for the capability to dynamically broaden the micro-focused beam size during an experiment. As is described in this paper, this can be achieved using a specially profiled X-ray mirrors or by using custom designed refractive optics. These two approaches have the effect of introducing a controlled distortion onto the X-ray wavefront and when the wavefront propagates to the focal plane, the distortion determines the intensity profile of the X-ray beam.