I20-Scanning-X-ray spectroscopy (XAS/XES)
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Diamond Proposal Number(s):
[31940]
Abstract: Epitaxial YBa 2 Cu3O7−δ/MgO thin films fabricated with pulsed laser deposition are grown as idealised epitaxial systems with a minimal number of different elements for X-ray absorption spectroscopy studies of irradiation damage. These films are characterised in terms of their superconducting performance, crystallinity, surface morphology, and Cu local environment. This reveals a structural heterogeneity of [100] oriented material, referred to as “a-axis grains”, decorating the desired [001] oriented phase of the thin film, coinciding with suppressed superconducting performance.
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Jan 2026
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Open Access
Abstract: We report the first experimental discovery of Hidden Satellites within the Kemission lines of manganese metal (Mn, ) with a total integrated statistical significance exceeding 270 (standard error), far beyond the discovery threshold. Experimental data were collected at the I20-Scanning beamline at the Diamond Light Source using our new eXtended-Range High-Energy-Resolution Fluorescence Detection (XR-HERFD) technique. The Hidden Satellites, embedded in the core emission structure, represent novel quantum many-body processes that evolve systematically as the incident photon energy increases. Principal Component Analysis (PCA) was applied to extract the major separable physical processes and validate the significance of the observed Hidden Satellites. The application of physical insight to the PCA method allowed us to isolate the satellites, and measure the evolutionary profile. Our paper reveals that the total intensity of shake-off satellites can reach as high as 20–25%. Although these are hidden, they are very significant. These results directly challenge the traditional treatment of the many-body reduction factor, , as a constant in the standard XAFS equation. Our findings demonstrate that this term must be modelled as an energy-dependent function, reflecting its variation with incident photon energy and highlighting its role in many-body interactions. This deeper understanding of fundamental atomic processes directly impacts relativistic quantum mechanics, in theory and application. Also, this develops the two most popular experimental techniques at synchrotrons: X-ray absorption and X-ray emission spectroscopy, responsible for some 12,000 papers per annum, and all applications of these techniques in chemistry, physics, and biology. It offers insights into the evolution of satellites and underscores the broader implications of hidden features in X-ray spectra.
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Dec 2025
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Jack
Stephens
,
Ramesh
Rijal
,
Daniel
Sier
,
Nicholas T. T.
Tran
,
Jonathan W.
Dean
,
Paul
Di Pasquale
,
Tony
Kirk
,
Minh
Dao
,
Chanh Q.
Tran
,
Shusaku
Hayama
,
Sofia
Diaz-Moreno
,
Christopher T.
Chantler
Diamond Proposal Number(s):
[39257]
Open Access
Abstract: The discovery of the novel n = 2 satellite transition in the Kβ emission spectrum of manganese and its evolution with incident photon energy are presented. Using the XR-HERFD (extended-range high-energy-resolution fluorescence detection) technique, we conclusively demonstrate the existence of this phenomenon with a statistical significance corresponding to 652 σse across the measured spectrum, far above the discovery threshold of 3–6 σse. We apply principal component analysis (PCA) to the XR-HERFD data to extract advanced structural insights. The evolution of this novel spectral feature and physical process are quantified by incorporating regression, revealing the increase in intensity over a wide range of incident photon energies. We validate these findings through independent test data. These results directly challenge the conventional treatment of the many-body reduction factor S02 as a constant independent of incident photon energy in the standard XAFS (X-ray absorption fine structure) equation. Thereby, these results present compelling evidence that S02 should be modelled as a varying function of incident photon energy, marking the first observation of this behaviour in Kβ spectra. This facilitates a greater quantitative understanding of HERFD spectra and a comprehensive representation of many-body effects in condensed matter systems.
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Sep 2025
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Ramesh
Rijal
,
Jack
Stephens
,
Daniel
Sier
,
Nicholas T. T.
Tran
,
Truong V. B.
Nguyen
,
Jonathan W.
Dean
,
Pierce
Bowman
,
Minh
Dao
,
Paul
Di Pasquale
,
Tony
Kirk
,
Chanh Q.
Tran
,
Shusaku
Hayama
,
Matteo
Aramini
,
Nitya
Ramanan
,
Sofia
Diaz-Moreno
,
Christopher T.
Chantler
Open Access
Abstract: This study of manganese (Mn, Z = 25) introduces a novel combination of extended-range high energy resolution fluorescence detection (XR-HERFD), multiple-crystal spectrometers and advanced binary data splicing techniques to address challenges in X-ray emission spectroscopy. XR-HERFD enhances spectral precision by utilizing high-resolution crystal analysers and optimized detector configurations. The systematic application of these methods using multiple Bragg crystal analysers at Diamond Light Source has led to substantial improvements in data quality. Simultaneously, advanced binary data splicing integrates multiple datasets to correct distortions and improve resolution, resulting in sharper spectral features. Our results show a significant increase in peak counts and a notable reduction in full width at half-maximum (FWHM), with peak amplitudes increasing by 83% and resolution improving by 46%. These developments provide greater detail for X-ray absorption or emission spectra, offering valuable insights into complex materials, and permitting advances and breakthroughs in atomic relativistic quantum mechanics, chemical sensitivity of atomic transitions and modelling of solid-state effects.
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Jul 2025
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Diamond Proposal Number(s):
[19223]
Abstract: High-charge micas exhibit improved adsorption properties and are a promising alternative clay material for the engineered barrier in deep geological repositories. When combined with Eu3+ cations, they serve as an in situ luminescent probe for tracking the physical–chemical changes occurring in this engineered barrier over the long term. Therefore, a better understanding of the local environment of the lanthanide is highly desirable to comprehend the specific behavior of these systems. A combination of different techniques, (X-ray diffraction, thermogravimetry, fluorescence, and X-ray absorption spectroscopy), has allowed the study of the local environment of two luminescent lanthanide cations, Eu3+ and Gd3+, embedded in the galleries of two high-charge micas with different Si/Al tetrahedral ratio. The results show that the hydration state of these cations is primarily influenced by the layer charge of the aluminosilicate, and secondarily by the cation’s hydration enthalpy. High-charge micas doped with trivalent lanthanide cations are more hydrated compared to the original clays with Na+ in the interlayer. Nevertheless, both Eu3+ and Gd3+ are adsorbed as inner-sphere complexes in the galleries of high-charge micas. They are located inside the distorted hexagonal cavity in all cases, coordinated by 3 oxygens from the tetragonal sheet, one fluorine from the octahedral sheet, and by 2–4 oxygens from water molecules, all at distances around 2.4 Å. An additional oxygen atom at a distance of 3.45–3.50 Å, is proposed from an H2O molecule in the second coordination shell.
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Jan 2025
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Abstract: X-ray absorption spectroscopy (XAS) is an established experimental technique for studying the electronic and local geometric structures of materials. As a short-range order structural probe, it can be applied to all states of matter: crystalline or amorphous solids, liquids and gases. The method is element selective and highly sensitive, with little compromise required to integrate complex sample environment set-ups. These characteristics make the technique suitable for applications in a range of scientific disciplines, from chemistry and catalysis to environmental science, materials science, physics, biology, medicine and cultural heritage. An XAS spectrum is obtained by measuring the modulation of the sample absorption coefficient as a function of the incident X-ray beam energy. Data are usually collected in transmission detection mode, although fluorescence and electron yield detection modes are often used. The XAS spectrum is divided into two regimes: X-ray absorption near-edge structure and extended X-ray absorption fine structure. In this Primer, an overview of XAS fundamentals is given, together with a description of the experimental set-ups, sample requirements, data analysis and possible applications.
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Dec 2024
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Abstract: The technique of extended-range high-energy-resolution fluorescence detection (XR-HERFD), developed from X-ray absorption spectroscopy, X-ray emission spectroscopy and resonant inelastic X-ray scattering (RIXS), has been used to successfully observe a new X-ray fluorescent satellite in manganese. The experimental methodology, spectral processing and analysis, and how statistical information and structure can be defined, extracted and used from HERFD spectra are detailed. Novel approaches to measure and improve accurate data uncertainty in XR-HERFD, HERFD and RIXS data sets are also presented. This includes definitions of intrinsic resolution and improvements to the resolution of the output and data by a factor of two relative to raw data or standard processing. Novel systematics common in HERFD and RIXS experiments are detailed, including background subtraction and elastic Bragg harmonics, with approaches to dealing with them.
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Dec 2024
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I20-Scanning-X-ray spectroscopy (XAS/XES)
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Diamond Proposal Number(s):
[28846]
Open Access
Abstract: Understanding irradiation damage of REBCO is increasingly of interest for compact tokamak fusion reactor designs, as these materials are critical for the proposed magnetic plasma confinement systems. Here commercially sourced samples of REBCO coated conductor are irradiated with 300 keV He+ ions to a damage level of 169×10-3 displacements-per-atom, to the point where superconductivity is no longer detectable, meaning these samples correspond to a non-functional end-of-life component in a fusion reactor context. Subsequent analysis of the crystal structure through a combination of X-ray diffraction and X-ray absorption spectroscopy measurements reveals a complex variation away from the as-grown structure. The local structure probed by the spectroscopy measurements is further observed to change as a function of the relative polarisation of the incident X-ray beam, indicating that within this damage regime the structural anisotropy of the REBCO unit cell plays a determining role in where defects accumulate within the material. Here the local structure measurements probing the a-b plane of the system vary significantly less than those probing the c-axis direction following irradiation, mirroring the observed trend in the X-ray diffraction data that the a:b ratio is preserved upon irradiation whilst the absolute values increase, whereas the c-axis parameter expands. These observations highlight the role of oxygen defect formation in driving the degradation of superconductivity within irradiated REBCO. These changes are observed to preferentially accumulate along the c-axis of the material, indicating a possible mechanistic signature of the degradation of the superconducting properties within these systems that are evident using a local structure probe such as EXAFS.
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Nov 2024
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I18-Microfocus Spectroscopy
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Diamond Proposal Number(s):
[31385]
Open Access
Abstract: A free-standing and compact reaction cell for combined in situ/operando x-ray spectroscopy, scattering, and imaging measurements at high pressures and high temperatures is described. The cell permits measurements under realistic operating conditions (up to 50 bar and 1000 °C), under static and flow conditions (up to 100 ml/min), over a wide range of hard x-ray energies, variable detection modes (transmission, fluorescence, and scattering), and at all angles of rotation. An operando XAS, x-ray fluorescence, x-ray computed tomography, and x-ray diffraction computed tomography case study on the reduction of a heterogeneous catalyst is presented to illustrate the performance of the reaction cell.
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Oct 2024
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Open Access
Abstract: Accurate analysis of the rich information contained within X-ray spectra usually calls for detailed electronic structure theory simulations. However, density functional theory (DFT), time-dependent DFT and many-body perturbation theory calculations increasingly require the use of advanced codes running on high-performance computing (HPC) facilities. Consequently, many researchers who would like to augment their experimental work with such simulations are hampered by the compounding of nontrivial knowledge requirements, specialist training and significant time investment. To this end, we present Web-CONEXS, an intuitive graphical web application for democratizing electronic structure theory simulations. Web-CONEXS generates and submits simulation workflows for theoretical X-ray absorption and X-ray emission spectroscopy to a remote computing cluster. In the present form, Web-CONEXS interfaces with three software packages: ORCA, FDMNES and Quantum ESPRESSO, and an extensive materials database courtesy of the Materials Project API. These software packages have been selected to model diverse materials and properties. Web-CONEXS has been conceived with the novice user in mind; job submission is limited to a subset of simulation parameters. This ensures that much of the simulation complexity is lifted and preliminary theoretical results are generated faster. Web-CONEXS can be leveraged to support beam time proposals and serve as a platform for preliminary analysis of experimental data.
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Sep 2024
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