Jisoo Kim receives the PSI Thesis Medal 2023. With this award, PSI recognises outstanding PhD theses, achieving a high degree of innovation and potentially leading to scientific breakthroughs. Jisoo holds a Master of Science from the Korean Advanced Institute of Science &Technology and defended his thesis entitled “Towards time-resolved X-ray scattering tensor tomography” at ETH Zürich.
Jisoo Kim was awarded the 2022 Werner Meyer-Ilse Memorial Award. The WMI Award is given to young scientists for exceptional contributions to the advancement of X-ray microscopy through either outstanding technical developments or applications, as evidenced by their presentation at the International Conference on X-ray Microscopy and supporting publications. Jisoo was awarded for his development of the method "Time-resolved x-ray scattering tomography for rheological studies", and is co-recipient of the award with Yanqi Luo from the Advanced Photons Source for her work on applications. The award was presented during the 15th International Conference on X-ray Microscopy XRM2022 hosted by the National Synchrotron Radiation Research Center (NSRRC) in Hsinchu, Taiwan on 19 - 24 June, 2022.
The orientation mismatch between the cone beam of an X-ray tube and the grating lines in a flat substrate remains a big challenge for laboratory grating-based X-ray interferometry, since it severely limits the imaging field of view. To solve this problem, we fabricated fan-shaped G0 source gratings by modulating the electric field during the deep reactive ion etching of silicon. With local electric field modulation in plasma we can etch high aspect ratio fan-shaped gratings that match the X-ray cone beam emission of a tube source. This new technology replaces the grating bending and allows a more compact design with larger field of view. Our work have recently been published in Applied Surface Science.
In the framework of the HERCULES European School about Neutrons & Synchrotron Radiation for Science which is coordinated by the Université de Grenoble Alpes and took place on February 28 – April 1, 2022, we were pleased to virtually host 4 students for a hands-on session. During this practical on “Absorption and phase contrast X-ray tomographic microscopy”, the students had the chance to go, with the help of a jupyter notebook and the guidance of our team members Margaux Schmeltz and Christian Schlepütz, through different examples of tomographic reconstructions. They learnt about basic decisions and tradeoffs that have to be taken into account when planning to acquire tomographic imaging data, were introduced to some segmentation tools and even got to play with dynamic tomographic data!
The X-ray Tomography group welcomes Marie-Christine Zdora as a new member. In her role as translational X-ray imaging adjunct scientist, Marie will mainly work on phase-contrast and dark-field imaging focusing on the further development of these techniques towards their clinical translation. Before joining TOMCAT, Marie was a postdoc in the X-ray optics and applications group at the Laboratory for Micro- and Nanotechnology (LMN) at PSI, where she worked on the development of new X-ray optics as well as X-ray wavefront sensing. Prior to this position, she was a research fellow at the University of Southampton in the UK, where she made advances in X-ray speckle-based imaging using synchrotron and lab sources.
Deep learning based classification of dynamic processes in time-resolved X-ray tomographic microscopy
Time-resolved X-ray tomographic microscopy provides new opportunities in the volumetric investigation of dynamic processes. Full exploitation of these new capabilities is currently still hindered by the lack of efficient post-processing approaches capable of handling TBs of noisy datasets. A deep learning based reconstruction and classification algorithm designed to reconstruct and segment dynamic processes within a static matrix with high efficiency is a solution to this issue. In a paper published recently in Scientific Reports, we demonstrate the advantages of the proposed approach on dynamic, time-resolved fuel cell data, for which the current data post-processing pipeline heavily relies on manual labor, typically limiting the experimental plans to just a small range of the full parameter space.
X-ray scattering tensor tomography facilitates the investigation of the microstructural organization in statistically large sample volumes. Established acquisition protocols based on scanning small-angle X-ray scattering and X-ray grating interferometry inherently require long scan times even with high brilliance X-ray sources. Recent developments in X-ray circular diffractive optics enable fast single-shot acquisition of the sample scattering properties with 2D omnidirectional sensitivity. Researchers from the TOMCAT beamline at Paul Scherrer Institut have proposed simple yet inherently rapid acquisition protocols for X-ray scattering tensor tomography leveraging these new optical elements. Results from both simulation and experimental data, supported by a null space analysis, suggest that the proposed acquisition protocols are rapid and corroborate, providing sufficient information for the accurate volumetric reconstruction of the scattering properties. The proposed acquisition protocols will be the cornerstones for rapid inspection or time-resolved tensor tomography of the microstructural organization over an extended field of view. The work is published in Scientific Reports on 29 November 2021.
In the framework of the 15th EXCITE Summer School in Biomedical Imaging which took place in Zürich on 6-17 September 2021, we were pleased to host 8 students at the beamline for a hands-on session. During this practical on “Synchrotron based X-ray tomographic microscopy”, the students had the chance to see and learn about the beamline infrastructure, scan a few test samples, reconstruct the tomographic volumes and discuss different aspects of tomographic microscopy at a synchrotron.
The X-ray Tomography group welcomes Craig Lawley as Postdoc in the X-ray optics design and fabrication team. He will contribute to developing the microfabrication process of hard X-ray gratings in silicon substrates suitable for preclinical testing with pitch size in the micrometer range and aspect ratio higher than 100.