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The article discusses the ongoing upgrade of the Advanced Photon Source (APS) and the implementation of advanced computational technologies for experiment control, data acquisition, and data analysis. The upgrade aims to make the APS the brightest hard X-ray synchrotron light source in the world. The article highlights the use of automated optics alignment and artificial intelligence/machine learning approaches for improved precision and efficiency in experiments. It also describes the development of a new control system for a spectroscopy beamline using Bluesky and Ophyd, which has already enabled user experiments during commissioning. The article emphasizes the importance of these advancements in handling the increasing volume of data generated at the APS and improving research opportunities. The APS is partnering with the Argonne Leadership Computing Facility (ALCF) to provide streamlined computing capabilities for researchers, including dedicated computing allocations and standardized processing workflows. The APS has also implemented a Fast Autonomous Scanning Toolkit (FAST) that uses neural networks and efficient hardware controls for scanning microscopy experiments. These advancements will enhance the capabilities of the APS and facilitate real-time data processing and analysis during experiments. [Extracted from the article]

A combined X-ray photon correlation spectroscopy and rheology study is carried out to capture the evolution of structure, fast particle-scale dynamics, and moduli (elastic and loss) at early times of gel formation near the fluid–gel boundary of a suspension of nanoparticles. The system is comprised of moderately concentrated suspensions of octadecyl silica in decalin (ϕ = 0.2) undergoing thermoreversible gelation. Near the gel boundary, the rate of gel formation is very sensitive to changes in attraction strength. However, we find that at different attraction strengths, the system goes through identical intermediate states of microscopic and macroscopic behavior, even though the absolute time needed to form a gel varies by orders of magnitude. We identify a single dimensionless time parameter, tw/tg, where tw is the wait time following the quench and tg is the rheologically determined gel time, that captures the similarity in gel formation at a range of attraction strengths. Following a temperature quench below the gel boundary, the system is initially fluidlike and forms diffusive clusters (∼8.5 times the particle diameter). After a lag-time, tL, clusters aggregate to form a network like structure which is characterized by the onset of mechanical rigidity and a rapid growth in microscopic relaxation times. At tg, the Baxter parameter obtained from adhesive hard sphere fits of the structure factor attains a constant value corresponding to the theoretical percolation boundary, thus demonstrating that gelation is percolation driven. [ABSTRACT FROM AUTHOR]

We are applying ML techniques to a variety of different X-ray characterization techniques at the APS to enable faster, more accurate data inversion than traditional methods. The APS is working to ensure that we can harness the extraordinary AI/ML opportunities that Aurora will provide to address the APS's most challenging AI/ML computational problems. The ongoing Advanced Photon Source Upgrade (APS-U) will replace the entire APS storage ring with a ring based on a reverse bend multi-bend achromat (MBA) lattice design. Artificial intelligence/machine learning (AI/ML) approaches have shown promise in not only speeding up but also expanding the potential robustness of X-ray data analysis methods, and are poised to play an increasing role in the APS-U Era. [Extracted from the article]

pyXPCSviewer, a Python-based graphical user interface that is deployed at beamline 8-ID-I of the Advanced Photon Source for interactive visualization of XPCS results, is introduced. pyXPCSviewer parses rich X-ray photon correlation spectroscopy (XPCS) results into independent PyQt widgets that are both interactive and easy to maintain. pyXPCSviewer is open-source and is open to customization by the XPCS community for ingestion of diversified data structures and inclusion of novel XPCS techniques, both of which are growing demands particularly with the dawn of near-diffraction-limited synchrotron sources and their dedicated XPCS beamlines. [ABSTRACT FROM AUTHOR]

The performance of the new 52 kHz frame rate Rigaku XSPA‐500k detector was characterized on beamline 8‐ID‐I at the Advanced Photon Source at Argonne for X‐ray photon correlation spectroscopy (XPCS) applications. Due to the large data flow produced by this detector (0.2 PB of data per 24 h of continuous operation), a workflow system was deployed that uses the Advanced Photon Source data‐management (DM) system and high‐performance software to rapidly reduce area‐detector data to multi‐tau and two‐time correlation functions in near real time, providing human‐in‐the‐loop feedback to experimenters. The utility and performance of the workflow system are demonstrated via its application to a variety of small‐angle XPCS measurements acquired from different detectors in different XPCS measurement modalities. The XSPA‐500k detector, the software and the DM workflow system allow for the efficient acquisition and reduction of up to ∼109 area‐detector data frames per day, facilitating the application of XPCS to measuring samples with weak scattering and fast dynamics. [ABSTRACT FROM AUTHOR]

This paper illustrates the use of spatial filtering with a horizontal slit near the source to enlarge the horizontal coherence in an experimental station and produce a diffraction‐limited round focus at an insertion device beamline for X‐ray photon correlation spectroscopy experiments. Simple expressions are provided to guide the optical layout, and wave propagation simulations confirm their applicability. The two‐dimensional focusing performance of Be compound refractive lenses to produce a round diffraction‐limited focus at 11 keV capable of generating a high‐contrast speckle pattern of an aerogel sample is demonstrated. The coherent scattering patterns have comparable speckle sizes in both horizontal and vertical directions. The focal spot sizes are consistent with hybrid ray‐tracing calculations. Producing a two‐dimensional focus on the sample can be helpful to resolve speckle patterns with modern pixel array detectors with high visibility. This scheme has now been in use since 2019 for the 8‐ID beamline at the Advanced Photon Source, sharing the undulator beam with two separate beamlines, 8‐ID‐E and 8‐ID‐I at 7.35 keV, with increased partially coherent flux, reduced horizontal spot sizes on samples, and good speckle contrast. [ABSTRACT FROM AUTHOR]

Vivid, saturated structural colors are conspicuous and important features of many animals. A rich diversity of three-dimensional periodic photonic nanostructures is found in the chitinaceous exoskeletons of invertebrates. Three-dimensional photonic nanostructures have been described in bird feathers, but they are typically quasi-ordered. Here, we report bicontinuous single gyroid β-keratin and air photonic crystal networks in the feather barbs of blue-winged leafbirds (Chloropsis cochinchinensis sensu lato), which have evolved from ancestral quasi-ordered channel-type nanostructures. Self-assembled avian photonic crystals may serve as inspiration for multifunctional applications, as they suggest efficient, alternative routes to single gyroid synthesis at optical length scales, which has been experimentally elusive. [ABSTRACT FROM AUTHOR]

Small‐angle X‐ray photon correlation spectroscopy (XPCS) measurements spanning delay times from 826 ns to 52.8 s were performed using a photon‐counting pixel array detector with a dynamic range of 0–3 (2 bits). Fine resolution and a wide dynamic range of time scales was achieved by combining two modes of operation of the detector: (i) continuous mode, where data acquisition and data readout are performed in parallel with a frame acquisition time of 19.36 µs, and (ii) burst mode, where 12 frames are acquired with frame integration times of either 2.56 µs frame−1 or 826 ns frame−1 followed by 3.49 ms or 1.16 ms, respectively, for readout. The applicability of the detector for performing multi‐speckle XPCS was demonstrated by measuring the Brownian dynamics of 10 nm‐radius gold and 57 nm‐radius silica colloids in water at room temperature. In addition, the capability of the detector to faithfully record one‐ and two‐photon counts was examined by comparing the statistical distribution of photon counts with expected probabilities from the negative binomial distribution. It was found that in burst mode the ratio of 2 s to 1 s is markedly smaller than predicted and that this is attributable to pixel‐response dead‐time. [ABSTRACT FROM AUTHOR]

Understanding and designing sophisticated new materials require measurements of not only their average structural properties but also their dynamic behavior. X-ray photon correlation spectroscopy (XPCS) provides this information by characterizing fluctuations in condensed matter across a broad range of length scales and timescales. Over the past two decades, XPCS has provided a wide variety of results in the study of materials properties. In this review, we provide an overview of coherence, photon correlation spectroscopy, and the dynamic structure factor as well as information on the mechanics of XPCS experiments. We highlight the impact that this infrastructure has had on materials research and the bright future that is forthcoming with the anticipated upgrade of many third-generation synchrotron sources to fourth-generation multibend achromat sources. [ABSTRACT FROM AUTHOR]

Multi‐speckle X‐ray photon correlation spectroscopy (XPCS) is a powerful technique for characterizing the dynamic nature of complex materials over a range of time scales. XPCS has been successfully applied to study a wide range of systems. Recent developments in higher‐frame‐rate detectors, while aiding in the study of faster dynamical processes, creates large amounts of data that require parallel computational techniques to process in near real‐time. Here, an implementation of the multi‐tau and two‐time autocorrelation algorithms using the Hadoop MapReduce framework for distributed computing is presented. The system scales well with regard to the increase in the data size, and has been serving the users of beamline 8‐ID‐I at the Advanced Photon Source for near real‐time autocorrelations for the past five years. [ABSTRACT FROM AUTHOR]

Abstract: Polymer/clay composite inks are exceptionally useful materials for fabrication processes based on 3D direct‐ink writing, however, there remains an insufficient understanding of how their physiochemical dynamics impact printability. Using a model system, N‐isopropylacrylamide/Laponite, the electrostatic interactions between Laponite platelets are modified to tune critical rheological properties in order to improve printability. Rheological measurements and X‐ray scattering experiments are carried out to monitor the nano/micro‐structural dynamics and complex physicochemical interactions of Laponite as it impacts complex modulus in the linear region, flow behavior, thixotropy, and yield stress of the composite ink. Modification of the electrostatic interactions between platelets reduces the yield stress of the material, while maintaining a complex microstructure that allows for sufficient recovery times upon removal of stress to form stable, and thus printable, filaments. A printing‐centric approach is established based on a fundamental understanding of electrostatic inter‐particle interactions, harnessing the innate microstructure of Laponite in 3D direct‐ink writing of composites. [ABSTRACT FROM AUTHOR]

ABSTRACT We present an X-ray photon correlation spectroscopy (XPCS) study of dynamic transitions in an anisotropic colloid-polymer dispersion with multiple arrested states. The results provide insight into the mechanism for formation of repulsive glasses, attractive glasses, and networked gels of colloids with weakly adsorbing polymer chains. In the presence of adsorbing polymer chains, we observe three distinct regimes: a state with slow dynamics consisting of finite particles and clusters, for which interparticle interactions are predominantly repulsive; a second dynamic regime occurring above the saturation concentration of added polymer, in which small clusters of nanoparticles form via a short-range depletion attraction; and a third regime above the overlap concentration in which dynamics of clusters are independent of polymer chain length. The observed complex dynamic state diagram is primarily governed by the structural reorganization of a nanoparticle cluster and polymer chains at the nanoparticle-polymer surface and in the concentrated medium, which in turn controls the dynamics of the dispersion. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 752-760 [ABSTRACT FROM AUTHOR]

The Vertically Integrated Photon Imaging Chip (VIPIC) was custom-designed for X-ray photon correlation spectroscopy, an application in which occupancy per pixel is low but high time resolution is needed. VIPIC operates in a sparsified streaming mode in which each detected photon is immediately read out as a time- and position-stamped event. This event stream can be fed directly to an autocorrelation engine or accumulated to form a conventional image. The detector only delivers non-zero data (sparsified readout), greatly reducing the communications overhead typical of conventional frame-oriented detectors such as charge-coupled devices or conventional hybrid pixel detectors. This feature allows continuous acquisition of data with timescales from microseconds to hours. In this work VIPIC has been used to measure X-ray photon correlation spectroscopy data on polystyrene latex nano-colliodal suspensions in glycerol and on colloidal suspensions of silica spheres in water. Relaxation times of the nano-colloids have been measured for different temperatures. These results demonstrate that VIPIC can operate continuously in the microsecond time frame, while at the same time probing longer timescales. [ABSTRACT FROM AUTHOR]

The static structure and dynamic behavior of cadmium sulfide nanoparticles suspended in block copolymer matrix are investigated using transmission electron microscopy, small-angle X-ray scattering, and X-ray photon correlation spectroscopy. The transmission electron microscopy study shows that cadmium sulfide nanoparticles are preferentially segregated within the polyisoprene domain of a poly(styrene- block-isoprene) diblock copolymer. For the dynamics study, X-ray photon correlation spectroscopy captures the relaxation process of cadmium sulfide nanoparticles. The measured characteristic relaxation time reveals that the observed dynamics are hyperdiffusive. The characteristic velocity and corresponding activation energy, which are hallmarks of a hyperdiffusive system, are determined from the relationship between the characteristic relaxation time and the wavevector. [ABSTRACT FROM AUTHOR]

The technique of speckle visibility spectroscopy has been employed for the measurement of dynamics using coherent X-ray scattering. It is shown that the X-ray contrast within a single exposure can be related to the relaxation time of the intermediate scattering function, and this methodology is applied to the diffusion of 72 nm-radius latex spheres in glycerol. Data were collected with exposure times as short as 2 ms by employing a resonant shutter. The weak scattering present for short exposures necessitated an analysis formalism based on the spatial correlation function of individual photon charge droplets on an area detector, rather than the usual methods employed for intensity correlations. It is demonstrated that this method gives good agreement between theory and experiment and thus holds promise for extending area-detector-based coherent scattering methods to the study of faster dynamics than previously obtainable. [ABSTRACT FROM AUTHOR]

As an increasingly important structural-characterization technique, grazing-incidence X-ray scattering (GIXS) has found wide applications for in situ and real-time studies of nanostructures and nanocomposites at surfaces and interfaces. A dedicated beamline has been designed, constructed and optimized at beamline 8-ID-E at the Advanced Photon Source for high-resolution and coherent GIXS experiments. The effectiveness and applicability of the beamline and the scattering techniques have been demonstrated by a host of experiments including reflectivity, grazing-incidence static and kinetic scattering, and coherent surface X-ray photon correlation spectroscopy. The applicable systems that can be studied at 8-ID-E include liquid surfaces and nanostructured thin films. [ABSTRACT FROM AUTHOR]

The 2010 Advanced Photon Source (APS) Users Meeting, held May 3-5 during Argonne's User Week, celebrated the 20th anniversary of groundbreaking for the APS, with the theme “Twenty Years of Groundbreaking Science.” [ABSTRACT FROM AUTHOR]

Complex three-dimensional biophotonic nanostructures produce the vivid structural colors of many butterfly wing scales, but their exact ñanoscale organization is uncertain. We used small angle X-ray scattering (SAXS) on single scales to characterize the 3D photonic nanostructures of five butterfly species from two families (Papilionidae, Lycaenidae). We identify these chitin and air nanostructures as single network gyroid (I4132) photonic crystals. We describe their optical function from SAXS data and photonic band-gap modeling. Butterflies apparently grow these gyroid nanostructures by exploiting the self-organizing physical dynamics of biological lipid-bilayer membranes. These butterfly photonic nanostructures initially develop within scale cells as a core-shell double gyroid (Ia3d), as seen in block-copolymer systems, with a pentacontinuous volume comprised of extracellular space, cell plasma membrane, cellular cytoplasm, smooth endoplasmic reticulum (SER) membrane, and intra-SER lumen. This double gyroid nanostructure is subsequently transformed into a single gyroid network through the deposition of chitin in the extracellular space and the degeneration of the rest of the cell. The butterflies develop the thermodynamically favored double gyroid precursors as a route to the optically more efficient single gyroid nanostructures. Current approaches to photonic crystal engineering also aim to produce single gyroid motifs. The biologically derived photonic nanostructures characterized here may offer a convenient template for producing optical devices based on biomimicry or direct dielectric infiltration. [ABSTRACT FROM AUTHOR]

The design and performance of a novel ultra-high-vacuum-compatible artificial channel-cut monochromator that has been commissioned at undulator beamline 8-ID-I at the Advanced Photon Source are presented. Details of the mechanical and optical design, control system implementation and performance of the new device are given. The monochromator was designed to meet the challenging stability and optical requirements of the X-ray photon correlation spectroscopy program hosted at this beamline. In particular, the device incorporates a novel in-vacuum sine-bar drive mechanism for the combined pitch motion of the two crystals and a flexure-based high-stiffness weak-link mechanism for fine-tuning the pitch and roll of the second crystal relative to the first crystal. The monochromator delivers an exceptionally uniform and stable beam and thereby improved brilliance preservation. [ABSTRACT FROM AUTHOR]

In 2007 the Advanced Photon Source (APS) joined with several other Argonne National Laboratory (ANL) user facilities to host Users' Week at ANL on May 7-12, 2007. The other facilities hosting sessions at the meeting were the Center for Nanoscale Materials (CNM), the Electron Microscopy Center (EMC), and the Intense Pulsed Neutron Source (IPNS). For the first time, these facilities participated in an integrated fashion with individual science sessions and joint cross-disciplinary workshops. More than 740 registered participants, the most in the history of this meeting, attended the 4 general science sessions and 11 joint workshops. [ABSTRACT FROM AUTHOR]

To determine the suitability of commonly used windows for small-angle X-ray scattering, a range of materials, including Kapton, (aluminized) Mylar, beryllium, high-purity aluminium foil, mica and silicon nitride have been studied. At small wavevector transfers, Q, in the range 2 × 10−3 to 0.2 nm−1, the scattering from Kapton, mica and beryllium is reasonably well described by power laws in Q with exponents of −3.25, −3.6 and −3.9, respectively. There are large variations in the scattering from mica, but a freshly cleaved natural mica window was by far the weakest scatterer. For applications where radiation in the infrared or visible range should be blocked, aluminized Mylar is the most suitable material. Both Mylar and Kapton can be used to make very simple demountable superfluid-tight windows using indium O-ring seals. [ABSTRACT FROM AUTHOR]

Measuring the deviation of a wavefront from a sphere provides valuable feedback on lens alignment and manufacturing errors. We demonstrate that these aberrations can be accurately measured at hard x-ray wavelengths, from far-field intensity measurements, using phase retrieval with a moveable structure in the beam path. We induce aberrations on a hard x-ray kinoform lens through deliberate misalignment and show that the reconstructed wavefronts are in good agreement with numerical simulations. Reconstructions from independent data, with the structure at different longitudinal positions and significantly separated from the beam focus, agreed with a root mean squared error of 0.006 waves. [ABSTRACT FROM AUTHOR]

Recent measurements of the scattering function and of the dynamics of surface and interfacial fluctuations in thin supported molten films and bilayers using synchrotron X-ray diffuse scattering and photon correlation spectroscopy in reflection geometry are reported. The results for monolayer films thicker than four times of the radius of gyration of polystyrene show behavior of normal over-damped capillary waves expected for the surface fluctuations of a viscous liquid. However, thinner films show deviations indicating the need to account for viscoelasticity. The theory has been extended to the surface and interfacial modes in a bilayer film system. The results are discussed in terms of surface tension, viscosity and shear modulus. Also recent experiments to measure the isothermal compressibility of supported polystyrene films by studying `bulk' scattering from the interior of the films is discussed. [ABSTRACT FROM AUTHOR]