This PDF file contains the front matter associated with SPIE Proceedings Volume 12698, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

X-ray tomography is a nondestructive technique that visualizes interior features in solid objects. To achieve a given resolution, a sufficient number of projection images over a cycle is required for 3D reconstruction based on the Crowther criterion. However, practical limitations such as geometrical constraints, data acquisition time, and low dose requirements often prohibit the acquisition of the full dataset, only allowing a limited angular range. The unsampled angles lead to the 'missing edge' problem in tomography, which introduces strong artifacts in reconstruction. To tackle this challenge, we propose an approach that integrates a Convolutional Neural Network (CNN) as a regularizer into an iterative solving engine. It combines perceptual prior knowledge about the sample with the physical model to produce an artifact-free solution. Our approach demonstrates excellent results with an experimental dataset with a missing edge of over 90 degrees.

Multilayer Laue lenses (MLLs) are promising optics for high efficiency nano focusing in the hard x-ray regime. However, since MLLs are one-dimensional focusing elements, a pair of MLLs need to be orthogonally aligned with respect to each other to achieve point focusing. This involves eight independent motions with nanoscale resolutions. This requirement poses significant technical challenges for a microscopy system and requires a highly specialized and stable instrument. The development of monolithic 2D MLL nano focusing optics could greatly reduce the instrument complexity, increase focusing stability, and minimize the degrees of a nanoscale motion needed for operating the MLL optics. A critical step in building 2D MLL optics is to ensure the orthogonality between two MLLs during the alignment. In this work, we report our approach for precise angular alignment of 2D MLL optics. This process, by utilizing a machine learning algorithm on the interferometer data, can automatically and precisely detect the small orthogonality error of 2D MLL optics. It is easy to use, accurate, and robust, and remarkably simplifies the procedure of 2D MLL alignment.

In situ multimodal microscopic x-ray characterizations demonstrate their unique capabilities in revealing the mechanisms of material degradation and the pathways for mitigation in energy harvesting applications such as halide perovskite solar cells. Despite the excellent device performance exhibited by halide perovskites, their sensitive nature and material interfaces necessitate a precisely controlled and tunable characterization environment to identify the sources of device performance loss. In this work, we designed an in-situ sample chamber that allows the control of various environmental conditions, including heat, illumination, and bias, while simultaneously collecting chemical (X-ray fluorescence, XRF), optical (X-ray Excited Optical Luminescence, XEOL), and performance (X-ray Beam Induced Current, XBIC) measurements on functional devices. The integrated thermoelectric cooler module of the designed chamber enables controlled heating up to 100 °C and rapid cooling back down to room temperature. This allows simultaneous multimodal XRF, XEOL and XBIC signal collections on Cs_0.05FA_0.95PbI₃ perovskite devices at various temperatures. The results show increasing homogeneity in the XBIC maps and continuous reduction in XEOL intensity, with a redshift in XEOL peak positions as sample temperatures increase. The results of the simultaneous multimodal study pave the way for improved in situ sample environments for future photovoltaic device characterizations.

Besides electron imaging in Scanning Electron Microscopy (SEM), techniques like Energy Dispersive X-ray spectroscopy (EDX) or Electron Backscatter Diffraction (EBSD) are widely established. With integration of a target holder and a pixelated x-ray detector, x-ray Computed Tomography (CT) in SEM can be realized and extends the modalities of materials characterization in one instrument. For nano-CT mode, an electron beam is focused on a suitable target leading to x-ray emission. While passing through a specimen, x-rays are differently attenuated depending on their material properties and detected by a direct converting x-ray detector afterward. Presented is a SEM-based nano-CT called XRM-II nanoCT and different applications of correlative microscopy using electron imaging, energy dispersive x-ray spectroscopy and CT. Besides multiscale investigation on materials for fuel cells and electrolysers by 3D visualization with micro- and nano-CT, nano-CT characterization of a catalytic converter with additional chemical analysis is depicted. At last, time-resolved imaging of morphology changes in an annealed Al alloy using nano-CT is presented. Results show grain coarsening as well as precipitations in the range of 200 – 1200 nm.

X-ray ptychography is one of the coherent x-ray diffractive imaging techniques with the object of interest scanned in small steps by an overlapping probe. The collected diffraction pattern set is reconstructed into real-space images of the sample by iterative phase retrieval calculation with a 10 nm order spatial resolution. The spectroscopic ptychography method is a combination of x-ray ptychography imaging and XAFS spectroscopy, where x-ray ptychography measurements are applied in x-ray energy around the target absorption edge. Thus, the reconstructed image stacks of the sample objects provide highly spatially resolved XAFS spectra of the non-uniform materials in nanoscale, which is considered to be the most promising tools for visualizing mesoscopic structures and chemical states (e.g., element composition, valence, local structures, etc.). Here, we report on our research and developments of hard x-ray spectroscopic ptychography systems at SPring-8, Japan, and show some demonstrations of the use of this method to visualize the chemical states of practical materials, especially battery material particles on the nano- and meso-scale. We have also developed x-ray ptychography in tender x-ray regions (2.5 keV) for the first time. This technique will be a powerful tool for analyzing samples containing sulfur, phosphorus, chlorine, etc., with high spatial resolution, such as battery materials, soft materials, and biomaterials.

X-ray ptychography is often implemented for nanoimaging at synchrotron radiation sources and extensions are being developed to make experiments faster. This work is on multi-beam ptychography with Fresnel zone plates that have a small lateral separation, enabling the imaging of an extended field of view without increasing exposure time. Sectional zone inversion is implemented for coding respective probes and up to three Fresnel zone plates are successfully used in parallel. The speed-up achieved, compared to single beam ptychography, is linear with the number of probes. The combination of versatility of the fabrication process for the Fresnel zone plates and performance enhancement by scanning in multi-beam mode makes this an optimal solution for studying samples fast and obtaining enlarged fields of view.

The diffraction of x-rays in quasi-perfect thin crystals of elements with high Z can generate multiple diffracted beams at the exiting surface of a crystal. These beams propagate in the free space parallel to each other and share the same divergence and monochromatic properties. These beams have a spatial separation that varies between few nm and couples of μm. Due to the different path that the photons follow, these x-ray beams present a temporal delay between each other in the order of the fs. It is for these that the x-ray beams generated by this ultrafast diffraction process are so-called x-ray echoes. The x-ray echoes can only be described using the dynamical diffraction theory formalism. Here, we present simulations with the expected diffracted wave-fronts both in the diffracted and forward direction in several compounds, such as Ni, GaAs, InSb and in particular Au. This work presents also the dependence with energy and thickness of the x-ray echoes. The properties of these x-ray beams can produce ambiguous results while performing temporal studies, that became obvious with fs and sub-fs pulse facilities. Moreover, the spatial overlapping of the echoes can mislead the scientist to think that speckles from a small crystal could be generated from different centers of diffraction, while in reality are a dynamical diffraction effect.

The Soft X-ray Nanoprobe (SXN) beamline, in development at Synchrotron NSLS-II under NEXT-II U.S. Department of Energy MIE project, is dedicated to soft x-ray scanning microscopy. It will offer researchers state-of-the-art soft x-ray nano-imaging and spectroscopy tools with world-leading coherent high photon flux in the energy range from 250 eV to 2500 eV and full polarization control with an aim to reach spatial resolution below 10 nm. It will provide element access from carbon (C) to sulfur (S) through K-edges and many other important elements through L- and M-edges. The primary endstation, nanoISM, will offer both a conventional Scanning Transmission X-ray Microscopy (STXM) mode, for high throughput 2D/3D absorption imaging, and a coherent diffractive imaging (ptychography) mode, for extra high spatial resolution. This article presents the design and status of the SXN beamline. The result of wave-optics- simulation allowed us to verify the beam performance from “source to sample” and supports the design of the beamline.

Synchrotrons accelerate and bend electron beams to create tangential, high-flux photons across a wide energy range. While synchrotrons are quite challenging to access with very expensive beamtime, there are several powerful analytical modalities accessible through this approach, including X-ray crystallography, infrared microscopy, powder diffraction, X-ray absorption spectroscopy, and others. Here we discuss X-ray fluorescence microscopy (XFM), another powerful application associated with Synchrotrons, and how recent advances in lab-based μXRF (micro X-ray fluorescence) spectroscopy can be used to inform proper synchrotron design of experiment and substitute for difficult to access synchrotron beamtime. Lab-based μXRF instruments now allow decentralized access to high spatial resolution elemental mapping of samples down to 5 μm spot excitation diameter. Data will be presented comparing synchrotron-generated elemental maps to lab-based μXRF for several different sample types, including cofactor migration tracking within biological tissue sections, element accumulation and distribution in plants, and mineralogy mapping.

We are developing a next-generation scanning x-ray microscope that will significantly enhance 3D ptychographic imaging capabilities available at NSLS-II. One of the important technical tasks pertains to providing high-speed data acquisition using fly-scanning, which may hold a significant advantage overstep scanning. The developed state-of-the-art x-ray microscope is EPICS-compatible and utilizes piezo actuators for fast raster scanning. The position is monitored by laser interferometers (or native encoders) and transferred to an FPGA-based device (Zebra box), which outputs detector trigger signals at a high frequency. The developed system is supported in a standard NSLS-II controls environment and can be implemented at existing and to-be-developed beamlines. At present, a similar fly-scanning capability is deployed at Submicron Resolution x-ray Spectroscopy (SRX) and Hard X-ray Nanoprobe (HXN) beamlines at NSLS-II.

At TPS 39A2 nanoARPES end station, the small space occupied by focusing devices such as the zone plate, Order Sorting Aperture (OSA), and detectors at the synchrotron end station makes collisions highly probable during adjustment or scanning. To address this issue, we developed a mechanical model using Solidworks to calculate the shortest distances among different objects after movement. Our approach utilizes a self-developed Software Development Kit (SDK) that can load an object description file to describe the spatial location and movement relation among triangle meshes. While the SDK can only calculate distance in static conditions and does not account for moving objects with speed or acceleration, we separated the program code and mechanical structure to ensure code portability. The collision.c and collision.h files are written in pure ANSI C code, and changes to the spatial or motion relation can be made by modifying the description file. The program was developed using National Instruments LabWindows/CVI and uses OpenGL to provide a visual and intuitive representation of the spatial relation between objects.