A Condenser Scanner for Artifact-Free, Large Field of View, Full-Field X-ray Microscopy at Synchrotrons

Most full-field microscopes at synchrotrons exhibit a highly peaked illumination in the center of the field of view for stationary condenser and objective optics. This illumination pattern is typically reference-corrected by division with an image without the sample to correct for the uneven illumination. However, this correction does not rectify problems such as the poor signal-to-noise ratio away from the center and the variation in image quality across the field of view due to the unbalanced illumination. These non-uniformity issues affect imaging strategies that stitch several fields of view together as is needed for large samples. We present the implementation of a condenser scanner that time-averages the illumination on the sample, leading to vastly improved image uniformity and the avoidance of image artifacts.