ABSTRACT
In this chapter, we describe X-ray diffraction tomography (XRDT) as a method for determining the molecular structure of an object at each voxel throughout its volume. After a brief review of the underlying physics of X-ray diffraction and existing XRDT methods, we focus on coded aperture XRDT (CA-XRDT). In CA-XRDT, one makes parallel, multiplexed measurements of the scatter from different voxels and uses a combination of physical layer coding and computational postprocessing to recover the localized scatter properties of the material. The advantages of this approach include the ability to realize novel, flexible architectures with higher photon throughputs for reduced scan times and/or dose as well as relatively simpler and/or less expensive components. After discussing the conceptual and mathematical underpinnings of CA-XRDT, we discuss the practical details associated with its experimental and computational implementation for a wide range of design choices. Finally, we discuss explicit examples of applications of CA-XRDT across medical, security, and industrial imaging and detection.
