Researchers from Argonne National Laboratory and Northwestern University are using ALCF supercomputing resources to develop new methods for nanoscale x-ray imaging of 3D objects. This visualization first shows the simulated propagation of a plane wave through a thick Fresnel zone plate, which is a widely used type of x-ray focusing optic. The zone plate is finely sampled on a gigavoxel-sized 3D array, which allows the propagating wavefield to be computed using the multislice technique. After the x-ray beam is focused on the sample, far-field diffraction patterns are collected while the sample is being constantly translated and rotated. The team uses multislice as a forward model of this process to calculate diffraction patterns produced by a present guess of the object, and then uses highly parallelized optimization-based methods to adjust the object guess to give a match to measured diffraction data. This allows the researchers to reconstruct the 3D volume of an arbitrarily thick object, beyond depth of focus and multiple scattering limits. This will be essential for future experiments using Argonne’s Advanced Photon Source as it is upgraded to a diffraction-limited storage ring.

Visualization: Ming Du, Argonne National Laboratory, Sajid Ali, Northwestern University, and Chris Jacobsen, Argonne National Laboratory/Northwestern University