Characterization of Materials through High Resolution Imaging: High Resolution Characterization of Materials with Coherent Diffraction Imaging
Sponsored by: TMS Structural Materials Division, TMS: Advanced Characterization, Testing, and Simulation Committee
Program Organizers: Richard Sandberg, Brigham Young University; Ross Harder, Argonne National Laboratory; Xianghui Xiao, Brookhaven National Laboratory; Brian Abbey, La Trobe University; Saryu Fensin, Los Alamos National Laboratory; Ana Diaz, Paul Scherrer Institute; Mathew Cherukara, Argonne National Laboratory
Wednesday 8:30 AM
March 17, 2021
Room: RM 14
Location: TMS2021 Virtual
Session Chair: Ana Diaz, Paul Scherrer Institute
8:30 AM Invited
Investigating the Early Life on Earth with Nanoscale X-ray Coherent Imaging: Lara Maldanis1; Douglas Galante2; 1Université Grenoble Alpes; 2Brazilian Synchrotron Light Laboratory
Deciphering the earliest records of life on Earth is a challenging undertaking, especially after billions of years of geological processing that obliterate original biological compounds and that can also generate biology-like structures. We explored ptychographic X-ray computed tomography (PXCT) to reveal in 3D the morphological and mineralogical components of ancient microfossils at the nanoscale. This unprecedented non-destructive investigation revealed ultracellular features with relevance for the unequivocal identification of controversial structures, while the quantitative electron density information identified organic and mineral components that shed light into the preservation processes. We will present how PXCT can contribute to the understanding of the earliest fossilized traces of life on Earth, and also for the investigation of near-future samples returned from Mars. We will also provide an overview of the latest developments of Sirius, the new Brazilian 4th generation synchrotron that will take advantage of a high coherent flux for different high-resolution imaging methods.
9:00 AM
Confocal Bragg Ptychography for 3D Mapping of Bulk Specimens: Henning Friis Poulsen1; 1DTU
We report on two new x-ray coherent imaging methods, that combine high spatial resolution with the ability to map volumes deep within polycrystalline specimens. In both an x-ray objective is introduced between the sample and the detector. Iterative oversampling routines and Fourier synthesis are used to reconstruct the shape and strain field from the far field intensity pattern. The first method, mimicking Bragg CDI, is shown experimentally to be reconstruct small but embedded grains in 3D without compromising the spatial resolution. In the second method, confocal Bragg ptychography, a local volume is defined by the dimensions of an incident pencil beam and the objective. Numerical simulations show a resolution of order 20 nm. The lens characteristics are shown to be not critical. The status and limitations of the methods will be outlined. This work is a collaboration between DTU, ESRF, Aix Marseille and MAX IV.
9:20 AM
Improve Phase Retrieval Performance in Bragg CDI by Simultaneous Reconstruction of Multiple Diffraction Peaks: Yuan Gao1; Garth Williams1; 1Brookhaven National Laboratory
Bragg coherent diffractive imaging (BCDI) is a non-invasive microscopy technique that can visualize the morphology and internal lattice deviations of crystals with nanoscale spatial resolution and picometer deformation sensitivity. While BCDI has been successfully applied in various studies of materials, it is less successful for highly strained crystals. Specifically, it is difficult to correctly reconstruct the electron density of a highly strained object using the conventional phase retrieval algorithms. Although various algorithms have been developed to overcome this challenge, most of them require a priori knowledge that is not always available in practice. Here we report on modified error reduction and hybrid input-output algorithms that can invert diffraction patterns from multiple Bragg peaks simultaneously. Due to the large degree of data redundancy, the new method is able to reliably reconstruct highly strained objects in a single run without a priori knowledge of the sample.
9:40 AM
Near-surface Optical Characterisation of Ion Implantation in Titanium Oxide Thin Films: Eugeniu Balaur1; Brian Abbey1; 1La Trobe University
Monitoring the dielectric properties of thin films is critical for both electronic applications and integrated circuit production but is often difficult to achieve using conventional imaging techniques. Here we present a new approach using optical coherent diffraction to characterise ion implantation in ultra-thin layers of titanium oxide. Analysis of the data enables us to characterise the doped regions in the films based on their near-surface optical contrast. Using Monte Carlo simulations and the Maxwell-Garnett relation, we are able to quantitatively interpret the observed results in terms of the ion implantation dose.
10:00 AM Invited
ID01 in Light of the ESRF-EBS: Steven Leake1; Peter Boesecke1; Tobias Schulli1; 1ESRF - The European Synchrotron
The ID01 beamline was built to combine Bragg diffraction with imaging techniques to produce a strain and mosaicity microscope for materials in their native or operando state[1]. Conceived with the upgraded ESRF-EBS source in mind over the past four years it has been optimised to exploit the new source to the maximum, typically delivering coherent focused x-ray beams of 50nm – 1μm in dimension [1,2]. The ESRF-EBS source will deliver increased coherent flux (x28), providing not only throughput and/or resolution gains but coherent diffractive imaging up to 35keV[3]. We will demonstrate the cutting edge available on ID01 today, the results of the first 6 months of operation with the ESRF-EBS and our perspective on the opportunities that are yet to be exploited. References: [1] S.J.Leake et al., J. Synchrotron Rad. (2019) https://doi.org/10.1107/S160057751900078X [2] S.J.Leake et al. Mat. & Design, (2017) https://doi.org/10.1016/j.matdes.2017.01.092[3] S.Maddali et al., arXiv:1903.11815 (2019) https://arxiv.org/abs/1903.11815
10:30 AM
Retrieving the Full 3D Strain Tensor for Nanoscale Materials Science Applications at 34-ID-C: Anastasios Pateras1; Ross Harder2; Wonsuk Cha2; Jonathan Gigax1; Jon Baldwin1; Jon Tischler2; Ruxing Xu2; Wenjun Liu2; Mark Erdmann2; Robert Kalt2; Richard Sandberg3; Saryu Fensin1; Reeju Pokharel1; 1Los Alamos National Laboratory; 2Argonne National Laboratory; 3Bringham Young University
Crystalline materials properties depend on their nanoscale structure. In micron to nanometer scale dimensions, knowing the crystallographic orientation and full strain tensor can predict the mechanical properties of particles and crystal grains of polycrystalline metals. Bragg coherent x-ray diffraction imaging allows the visualization of the local atomic lattice displacement of single nanoparticles or grains in 3D. However, measurement modalities in Bragg coherent diffraction imaging broadly rely on a single crystalline grain satisfying the Bragg condition within a potentially large population of sub-micrometer scale crystals with unknown crystallographic orientations. We report the commissioning of a movable monochromator at the 34-ID-C end station of the Advanced Photon Source, which delivers multi-reflection BCDI and full strain tensor 3D imaging as a standard tool in a single beamline instrument. We discuss the design and concept of operation of the instrument, and show examples of materials science applications that would benefit from the new capabilities.
10:50 AM
Multi-peak Phase Retrieval for Coherent X-ray Diffraction Imaging at High Energies: Matthew Wilkin1; Anthony Rollett1; 1Carnegie Mellon University
Bragg Coherent X-ray Diffraction Imaging (BCDI) non-destructively allows for the study of nano-scale defect interactions through the reconstruction of a coherent diffraction pattern. While one Bragg peak provides a projection of the strain along a particular plane normal, it has recently been demonstrated that, by measuring patterns from multiple Bragg reflections and reconstructing them through concurrent phase retrieval, the full strain tensor can be recovered. In the study of bulk polycrystals using high energy BCDI, partial coherence seriously affects the ability to consistently reconstruct Bragg peaks. We propose a new method for strain calculation when peak quality is variable. Using a reconstruction confidence index, Bragg peaks are weighted using least squares weighted fit, giving higher weight to peaks which converge more consistently than others, resulting in more accurate strain tensor recovery.
11:10 AM Invited
X-ray Imaging of Three-dimensional Magnetic Systems and Their Dynamics: Claire Donnelly1; 1University of Cambridge
Three-dimensional magnetic systems promise significant opportunities for both fundamental physics, and applications [1,2]. However, their experimental realisation requires new characterisation techniques. We have developed X-ray magnetic nanotomography [3], providing access to the three-dimensional magnetic configuration at the nanoscale. In a first demonstration, we determined the three-dimensional magnetic structure within the bulk of a magnetic micropillar that contains vortices and antivortices, as well as Bloch point singularities [3]. In addition, the dynamic response of three-dimensional magnetic configurations is key. We have developed pump-probe X-ray magnetic laminography, providing access to the magnetisation dynamics of a three-dimensional magnetic system [4]. These new experimental capabilities unlock the elucidation of complex three-dimensional magnetic structures, and their dynamic behaviour. [1] Fernández-Pacheco et al., Nature Comm. 8, 15756 (2017) [2] Donnelly and Scagnoli, J. Phys. D (2019). [3] Donnelly et al., Nature 547, 328 (2017). [4] Donnelly et al., Nature Nanotechnology 15, 356 (2020).