Publications by authors named "Matthew G Frith"

Next-generation synchrotron radiation facilities, such as the Advanced Photon Source Upgrade (APS-U), bring significant advancements in scientific research capabilities, necessitating advanced diagnostic tools. Central to these diagnostics are x-ray wavefront sensors, crucial for preserving beam properties, including brightness, coherence, and stability. This paper presents two novel wavefront sensor prototypes developed at the APS using the coded-mask-based technique.

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We describe the application of an AI-driven system to autonomously align complex x-ray-focusing mirror systems, including mirrors systems with variable focus spot sizes. The system has been developed and studied on a digital twin of nanofocusing X-ray beamlines, built using advanced optical simulation tools calibrated with wavefront sensing data collected at the beamline.We experimentally demonstrated that the system is reliably capable of positioning a focused beam on the sample, both by simulating the variation of a beamline with random perturbations due to typical changes in the light source and optical elements over time, and by conducting similar tests on an actual focusing mirror system.

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A neural-network machine learning model is developed to control a bimorph adaptive mirror to achieve and preserve aberration-free coherent X-ray wavefronts at synchrotron radiation and free electron laser beamlines. The controller is trained on a mirror actuator response directly measured at a beamline with a real-time single-shot wavefront sensor, which uses a coded mask and wavelet-transform analysis. The system has been successfully tested on a bimorph deformable mirror at the 28-ID IDEA beamline of the Advanced Photon Source at Argonne National Laboratory.

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Colloidal gels result from the aggregation of Brownian particles suspended in a solvent. Gelation is induced by attractive interactions between individual particles that drive the formation of clusters, which in turn aggregate to form a space-spanning structure. We study this process in aluminosilicate colloidal gels through time-resolved structural and mechanical spectroscopy.

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Hypothesis: Understanding the stability and rheological behavior of suspensions composed of anisotropic particles is challenging due to the complex interplay of hydrodynamic and colloidal forces. We propose that orientationally-dependent interactions resulting from the anisotropic nature of non-spherical sub-units strongly influences shear-induced particle aggregation/fragmentation and suspension rheological behavior.

Experiments: Wide-, small-, and ultra-small-angle X-ray scattering experiments were used to simultaneously monitor changes in size and fractal dimensions of boehmite aggregates from 6 to 10,000 Å as the sample was recirculated through an in-situ capillary rheometer.

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In this paper, the composition, structure, morphology and kinetics of evolution during isothermal oxidation of FeCrMoYCB metallic glass powder in the supercooled region are investigated by an integrated ex-situ and in-situ characterization and modelling approach. Raman and X-ray diffraction spectra established that oxidation yielded a hierarchical structure across decreasing length scales. At larger scale, FeO grows as a uniform shell over the powder core.

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Hydrogen gas is formed when Mg corrodes in water; however, the manner and extent to which the hydrogen may also enter the Mg metal is poorly understood. Such knowledge is critical as stress corrosion cracking (SCC)/embrittlement phenomena limit many otherwise promising structural and functional uses of Mg. Here, we report via DO/D isotopic tracer and HO exposures with characterization by secondary ion mass spectrometry, inelastic neutron scattering vibrational spectrometry, electron microscopy, and atom probe tomography techniques direct evidence that hydrogen rapidly penetrated tens of micrometers into Mg metal after only 4 h of exposure to water at room temperature.

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