title: Crystal optics as guard apertures for coherent x-ray diffraction imaging.
abstract: A crucial issue in coherent x-ray diffraction imaging experiments is how to increase the signal-to-noise ratio when measuring relatively weak diffraction intensities from a nonperiodic object. A novel crystal guard aperture is described that makes use of a pair of multiple-bounce crystal optics to eliminate unwanted parasitic scattering background. This background is often produced by upstream optical elements such as a coherent-beam defining aperture. Recent experimental observation and theoretical analysis confirm the effectiveness of the crystal guard aperture method with coherence-preserved wave propagation through the crystal guard aperture and dramatically reduced scattering background in coherent x-ray diffraction images.
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA. xhxiao@aps.anl.gov
authors.forename: Xianghui
authors.initials: X
authors.lastname: Xiao
authors.forename: Martin D
authors.initials: MD
authors.lastname: de Jonge
authors.forename: Yuncheng
authors.initials: Y
authors.lastname: Zhong
authors.forename: Yong S
authors.initials: YS
authors.lastname: Chu
authors.forename: Qun
authors.initials: Q
authors.lastname: Shen