Support for Saugat Kandel

Saugat Kandel, working on the behalf of Northwestern University, will be working on coherent diffractive imaging (CDI) theory, experiments, and algorithmic development, with a specific focus on CDI for high energy X-rays (>40 keV). Specifically, his research will address the problem of 3D image reconstruction from high energy coherent X‐ray Bragg diffraction patterns. This area remains largely unexplored due to the limited coherence at current high energy X‐ray sources, and the inability of commonly used phase retrieval algorithms to handle under‐sampled data sets. This work will be integrated into the imaging capabilities at sector 1-ID-D at the APS and will rely on computational resources at the ALCF for iterative reconstruction of large‐scale data sets. Furthermore, the approach will have immediate impact for APS‐U beamlines such as HEXM, ATOMIC, and CHEX that emphasize in situ characterization of heterogeneous materials and require the penetrating ability of hard X‐rays. He will work in close collaboration with Dr. Stephan Hruszkewycz and Dr. Siddharth Maddali at the Synchrotron Radiation Studies Group of the Materials Science Division (MSD) at Argonne. His work will involve simulation of coherent high-energy diffraction experiments and data analysis at Northwestern University, participation in occasional meetings at Argonne, and work at Argonne. His deliverables for the above period include the following: • Quarterly summaries of progress • Simulating data from coherent high-energy diffraction experiments • Investigating failure points for current Bragg phase retrieval methods