Fast reconstruction tools for ptychography at Sirius, the fourth-generation Brazilian synchrotron

Abstract

Described here are image reconstruction optimizations for ptychographic coherent X-ray scattering data and X-ray fluorescence, which have been developed for the new fourth-generation synchrotron light source, Sirius, at the Brazilian Synchrotron Light Laboratory. The optimization strategy has been applied to the standard experimental strategy for ptychographic and fluorescence experiments on the Carnaúba beamline which involves the use of high-speed continuous scans (fly scans) for a fast acquisition time over large areas through the use of a newly proposed trajectory named the alternating linear trajectory. The scientific computing developments presented here target an efficient use of graphical processing units (GPUs) to the point where large fly-scan acquisitions can be processed in real time on a local high-performance computer. Some optimizations involving a custom fast Fourier transform implementation and use of mixed precision can be applied to other algorithms and phase-retrieval techniques, and therefore this work provides a general optimization scheme. Finally, the optimization strategy presented here has improved performance by a factor of ∼2.5 times faster when compared with non-optimized GPU implementations.

An approach for the optical and mechanical design of an X-ray beamline: application to the plane-wave CDI station CATERETÊ/SIRIUS

“…Nonetheless, the reconstructed sample shows high contrast, with a pixel size of 64 nm. The reconstruction was performed by a mixture of the alternating projections and RAAR algorithms [18]. More efforts are underway to quantitatively assess the coherence properties of the beam.…”

Schwartz Symmetry Condition for Coherent Diffraction Imaging Patterns

“…To illustrate our methodology, we present a radiographic projection recovered using the ptychography technique [22] with data collected at the fourth-generation Brazilian Synchrotron beamline CATERETE [23]. The measurements were taken at a distance of 14m with an energy of 3.8 KeV.…”

Introduction to the special issue on Ptychography: software and technical developments

“…(6) Lastly, there were several contributions showcasing new computer codes and software, as was to be expected from a developers' conference. Baraldi et al (2020) describe highly optimized software tools for fast ptychographic reconstructions, particularly suited to the high-speed fly scans that have been developed at Sirius. Wakonig et al (2020) introduce PtychoShelves, a high-performance modular framework for ptychographic reconstructions developed at the Paul Scherrer Institute, but which has been tested at a variety of light sources including home sources and electron sources.…”