This time, we will have shorter presentations by two PhD students from the Synchrotron Radiation Research division. We hope to see more PhD student and postdoc presentations in the future, so if you have any suggestions just send us an email.

Hanna Dierks will talk about  “Propagation-based phase contrast imaging with laboratory X-ray sources”

X-ray microscopy using propagation-based phase contrast (PB-PC) is a powerful technique to study low absorption samples, e.g., soft tissue or plastics on the micrometer scale. It is characterized by the appearance of additional ‘edge-enhancement fringes’ in the X-ray projection images. When transferring the method from synchrotron experiments to lab setups with a divergent X-ray source a trade-off between the distance-dependent flux, magnification and coherence must be made when choosing the geometry. I will present a systematic investigation of this trade-off, based on experiments with 3 different lab setups located at Lund University: a low-magnification setup with a reflection micro-focus source and high-resolution detector, a commercial integrated system (Zeiss Xradia) and a high-magnification setup using a nano-focus transmission source and low-resolution detector. Based on the measurements and theory, some simple rules for designing a PB-PC imaging experiment are presented.

Isac Lazar will talk about “In-situ observation of precipitate formation using scanning X-ray fluorescence in novel Al alloy tailored for additive manufacturing”

In this study, in-situ formation and growth of different Mn and Cr enriched precipitates was imaged while annealing a 3D-printed Al alloy. The investigated material belongs to a family of Al-Mn-Cr-Zr based alloys tailored for the powder bed fusion-laser beam process and the study was conducted using synchrotron scanning X-ray fluorescence at the P06 beamline at DESY, Hamburg. In-situ heat treatments showed selective accumulation of Cr and Mn in two types of precipitates, with a possible splitting or co-precipitation phenomenon of precipitates at grain boundaries. The method proved to be a valuable tool in studying the kinetics of micrometre-scale precipitation and the results can be used as direct input for future alloy designs.