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Resonant inelastic X-ray scattering (RIXS) is an ideal X-ray spectroscopy method to push the combination of energy and time resolutions to the Fourier transform ultimate limit, because it is unaffected by the core-hole lifetime energy broadening. Also, in pump–probe experiments the interaction time is made very short by the same core-hole lifetime. RIXS is very photon hungry so it takes great advantage from high-repetition-rate pulsed X-ray sources like the European XFEL. The Heisenberg RIXS instrument is designed for RIXS experiments in the soft X-ray range with energy resolution approaching the Fourier and the Heisenberg limits. It is based on a spherical grating with variable line spacing and a position-sensitive 2D detector. Initially, two gratings were installed to adequately cover the whole photon energy range. With optimized spot size on the sample and small pixel detector the energy resolution can be better than 40 meV (90 meV) at any photon energy below 1000 eV with the high-resolution (high-transmission) grating. At the SCS instrument of the European XFEL the spectrometer can be easily positioned thanks to air pads on a high-quality floor, allowing the scattering angle to be continuously adjusted over the 65–145° range. It can be coupled to two different sample interaction chambers, one for liquid jets and one for solids, each state-of-the-art equipped and compatible for optical laser pumping in collinear geometry. The measured performances, in terms of energy resolution and count rate on the detector, closely match design expectations. The Heisenberg RIXS instrument has been open to public users since the summer of 2022.

Isotopic dating is a valuable method to constrain the timing of lithospheric processes: geodynamic episodes, ore deposition and geothermal regimes. The K–Ar dating technique has the main advantage of being applied to ubiquitous K-bearing minerals that crystallize at various temperatures, from magmatic to low temperatures. Clays are of significant interest among all K-bearing minerals, as they crystallize during various hydrothermodynamic processes. Nonetheless, the dating of illites by the K–Ar method is not straightforward. K–Ar dates on illite usually rely on a mixed isotopic signal referring to various illitic populations that might have experienced isotopic resetting or recrystallization processes. Therefore, reliable K–Ar dates on illite depend on (1) the grain size separation of large numbers of clay fractions; (2) the study of the morphology, mineralogy and crystallography; (3) the determination of precise K–Ar dates on each clay size fraction; and (4) the meaningful interpretation of ages using either end-member ages or the illite age analysis (IAA) method. This paper describes the instrumentation and methods recently developed at the GeoRessources laboratory of the University of Lorraine to obtain valuable ages on illite mixtures.

The European Commission’s 2015 aging report forecasts a substantial increase in public spending on Long-Term Care (LTC) for OECD countries by 2060, posing significant fiscal challenges. This study aims to assess the efficiency and productivity of the LTC sector from 2010 to 2019 and explore whether efficiency gains can alleviate these fiscal pressures. Using a non-parametric Data Envelopment Analysis (DEA) model, combined with Tobit regression, we estimate the efficiency of OECD countries and examine the role of decentralization in shaping performance outcomes. The findings reveal that, on average, countries operate at 94% efficiency, with modest productivity growth. However, technical inefficiencies persist, especially in unitary countries, while federal countries, though initially less efficient, show greater improvements over time. Despite these gains, the current efficiency levels are insufficient to counterbalance the projected increase in LTC demand. Policymakers should prioritize reforms that enhance efficiency through decentralization, promoting accountability and competition as mechanisms to sustain the LTC system in the face of demographic shifts.

The advent of X-ray free-electron lasers (XFELs) has revolutionized fundamental science, from atomic to condensed matter physics, from chemistry to biology, giving researchers access to X-rays with unprecedented brightness, coherence and pulse duration. All XFEL facilities built until recently provided X-ray pulses at a relatively low repetition rate, with limited data statistics. Here, results from the first megahertz-repetition-rate X-ray scattering experiments at the Spectroscopy and Coherent Scattering (SCS) instrument of the European XFEL are presented. The experimental capabilities that the SCS instrument offers, resulting from the operation at megahertz repetition rates and the availability of the novel DSSC 2D imaging detector, are illustrated. Time-resolved magnetic X-ray scattering and holographic imaging experiments in solid state samples were chosen as representative, providing an ideal test-bed for operation at megahertz rates. Our results are relevant and applicable to any other non-destructive XFEL experiments in the soft X-ray range.

The complex electronic structure of metallic ferromagnets is determined by a balance between exchange interaction, electron hopping leading to band formation, and local Coulomb repulsion. By combining high energy and temporal resolution in femtosecond time-resolved X-ray absorption spectroscopy with ab initio time-dependent density functional theory we analyze the electronic structure in fcc Ni on the time scale of these interactions in a pump-probe experiment. We distinguish transient broadening and energy shifts in the absorption spectra, which we demonstrate to be captured by electron repopulation respectively correlation-induced modifications of the electronic structure, requiring to take the local Coulomb interaction into account.

Abstract Resonant absorption of a photon by bound electrons in a solid can promote an electron to another orbital state or transfer it to a neighboring atomic site. Such a transition in a magnetically ordered material could affect the magnetic order. While this process is an obvious road map for optical control of magnetization, experimental demonstration of such a process remains challenging. Exciting a significant fraction of magnetic ions requires a very intense incoming light beam, as orbital resonances are often weak compared to above‐band‐gap excitations. In the latter case, a sizeable reduction of the magnetization occurs as the absorbed energy increases the spin temperature, masking the non‐thermal optical effects. Here, using ultrafast X‐ray spectroscopy, this work is able to resolve changes in the magnetization state induced by resonant absorption of infrared photons in Co‐doped yttrium iron garnet, with negligible thermal effects. This work finds that the optical excitation of the Co ions affects the two distinct magnetic Fe sublattices differently, resulting in a transient non‐collinear magnetic state. The present results indicate that the all‐optical magnetization switching (AOS) most likely occurs due to the creation of a transient, non‐collinear magnetic state followed by coherent spin rotations of the Fe moments.

Femtosecond transient soft X-ray absorption spectroscopy (XAS) is a very promising technique that can be employed at X-ray free-electron lasers (FELs) to investigate out-of-equilibrium dynamics for material and energy research. Here, a dedicated setup for soft X-rays available at the Spectroscopy and Coherent Scattering (SCS) instrument at the European X-ray Free-Electron Laser (European XFEL) is presented. It consists of a beam-splitting off-axis zone plate (BOZ) used in transmission to create three copies of the incoming beam, which are used to measure the transmitted intensity through the excited and unexcited sample, as well as to monitor the incoming intensity. Since these three intensity signals are detected shot by shot and simultaneously, this setup allows normalized shot-by-shot analysis of the transmission. For photon detection, an imaging detector capable of recording up to 800 images at 4.5 MHz frame rate during the FEL burst is employed, and allows a photon-shot-noise-limited sensitivity to be approached. The setup and its capabilities are reviewed as well as the online and offline analysis tools provided to users.

Free-electron lasers provide bright, ultrashort, and monochromatic x-ray pulses, enabling novel spectroscopic measurements not only with femtosecond temporal resolution: The high fluence of their x-ray pulses can also easily enter the regime of the non-linear x-ray–matter interaction. Entering this regime necessitates a rigorous analysis and reliable prediction of the relevant non-linear processes for future experiment designs. Here, we show non-linear changes in the L 3-edge absorption of metallic nickel thin films, measured with fluences up to 60 J/cm2. We present a simple but predictive rate model that quantitatively describes spectral changes based on the evolution of electronic populations within the pulse duration. Despite its simplicity, the model reaches good agreement with experimental results over more than three orders of magnitude in fluence, while providing a straightforward understanding of the interplay of physical processes driving the non-linear changes. Our findings provide important insights for the design and evaluation of future high-fluence free-electron laser experiments and contribute to the understanding of non-linear electron dynamics in x-ray absorption processes in solids at the femtosecond timescale.

The advent of X-ray free-electron lasers (XFELs) has revolutionized fundamental science, from atomic to condensed matter physics, from chemistry to biology, giving researchers access to X-rays with unprecedented brightness, coherence and pulse duration. All XFEL facilities built until recently provided X-ray pulses at a relatively low repetition rate, with limited data statistics. Here, results from the first megahertz-repetition-rate X-ray scattering experiments at the Spectroscopy and Coherent Scattering (SCS) instrument of the European XFEL are presented. The experimental capabilities that the SCS instrument offers, resulting from the operation at megahertz repetition rates and the availability of the novel DSSC 2D imaging detector, are illustrated. Time-resolved magnetic X-ray scattering and holographic imaging experiments in solid state samples were chosen as representative, providing an ideal test-bed for operation at megahertz rates. Our results are relevant and applicable to any other non-destructive XFEL experiments in the soft X-ray range.

The SASE3 soft X-ray beamline at the European XFEL has been designed and built to provide experiments with a pink or monochromatic beam in the photon energy range 250–3000 eV. Here, the focus is monochromatic operation of the SASE3 beamline, and the design and performance of the SASE3 grating monochromator are reported. The unique capability of a free-electron laser source to produce short femtosecond pulses of a high degree of coherence challenges the monochromator design by demanding control of both photon energy and temporal resolution. The aim to transport close to transform-limited pulses poses very high demands on the optics quality, in particular on the grating. The current realization of the SASE3 monochromator is discussed in comparison with optimal design performance. At present, the monochromator operates with two gratings: the low-resolution grating is optimized for time-resolved experiments and allows for moderate resolving power of about 2000–5000 along with pulse stretching of a few to a few tens of femtoseconds RMS, and the high-resolution grating reaches a resolving power of 10 000 at the cost of larger pulse stretching.

Abstract Microbialites and peloids are commonly associated throughout the geologic record. Proterozoic carbonate megafacies are composed predominantly of micritic and peloidal limestones often interbedded with stromatolitic textures. The association is also common throughout carbonate ramps and platforms during the Phanerozoic. Recent investigations reveal that Hamelin Pool, located in Shark Bay, Western Australia, is a microbial carbonate factory that provides a modern analog for the microbialite-micritic sediment facies associations that are so prevalent in the geologic record. Hamelin Pool contains the largest known living marine stromatolite system in the world. Although best known for the constructive microbial processes that lead to formation of these stromatolites, our comprehensive mapping has revealed that erosion and degradation of weakly lithified microbial mats in Hamelin Pool leads to the extensive production and accumulation of sand-sized micritic grains. Over 40 km2 of upper intertidal shoreline in the pool contain unlithified to weakly lithified microbial pustular sheet mats, which erode to release irregular peloidal grains. In addition, over 20 km2 of gelatinous microbial mats, with thin brittle layers of micrite, colonize subtidal pavements. When these gelatinous mats erode, the micritic layers break down to form platey, micritic intraclasts with irregular boundaries. Together, the irregular micritic grains from pustular sheet mats and gelatinous pavement mats make up nearly 26% of the total sediment in the pool, plausibly producing ~ 24,000 metric tons of microbial sediment per year. As such, Hamelin Pool can be seen as a microbial carbonate factory, with construction by lithifying microbial mats forming microbialites, and erosion and degradation of weakly lithified microbial mats resulting in extensive production of sand-sized micritic sediments. Insight from these modern examples may have direct applicability for recognition of sedimentary deposits of microbial origin in the geologic record.

The electrical properties of rocks are widely used in the geophysical exploration of natural resources, such as minerals, hydrocarbons and groundwater. In mining exploration, the primary goal is to map electrically anomalous geological features associated with different mineralization styles, such as clay alteration haloes, metal oxides and sulphides, weathered crystalline rocks or fractured zones. As such, the reconciliation of geophysical data with geological information (geochemistry, mineralogy, texture and lithology) is a critical step and can be performed based on petrophysical properties collected either on core samples or as downhole measurements. Based on data from 189 diamond drill cores collected for uranium exploration in the Athabasca Basin (Saskatchewan, Canada), this paper presents a case study of reconciliation of downhole resistivity probing with core sample geochemistry and short‐wave infrared spectroscopy (350–2500 nm) through three successive steps: (i) multivariate analysis of resistivity and other petrophysical properties (porosity, density) against geochemical and infrared spectroscopy information to characterize electrical properties of rocks with respect to other physical parameters, (ii) a machine‐learning workflow integrating geochemistry and spectral signatures in order to infer synthetic resistivity logs along with uncertainties. The best model in the basin was Light Gradient‐Boosting Machine with pairwise log‐ratio, which yielded a coefficient of determination R2 = 0.80 (root mean square error = 0.16), and in the basement, support vector regression with data fusion of infrared spectroscopy and pairwise log‐ratios on geochemistry yielded R2 = 0.82 (root mean square error = 0.35); (iii) the best model was then fitted on an area that was excluded from the original dataset (Getty Russell property) in order to infer synthetic resistivity logs for that zone. Software code is publicly available. This workflow can be re‐used for the valorization of legacy datasets. [ABSTRACT FROM AUTHOR]

The European Commission's 2015 aging report forecasts a substantial increase in public spending on Long-Term Care (LTC) for OECD countries by 2060, posing significant fiscal challenges. This study aims to assess the efficiency and productivity of the LTC sector from 2010 to 2019 and explore whether efficiency gains can alleviate these fiscal pressures. Using a non-parametric Data Envelopment Analysis (DEA) model, combined with Tobit regression, we estimate the efficiency of OECD countries and examine the role of decentralization in shaping performance outcomes. The findings reveal that, on average, countries operate at 94% efficiency, with modest productivity growth. However, technical inefficiencies persist, especially in unitary countries, while federal countries, though initially less efficient, show greater improvements over time. Despite these gains, the current efficiency levels are insufficient to counterbalance the projected increase in LTC demand. Policymakers should prioritize reforms that enhance efficiency through decentralization, promoting accountability and competition as mechanisms to sustain the LTC system in the face of demographic shifts. [ABSTRACT FROM AUTHOR]

The Fregeneda-Almendra pegmatite field of the Iberian Massif represents a typical expression of peraluminous rare-metal magmatism that occurred over western Europe at the end of the Variscan orogeny. It is the host for two main types of Li-mineralized intrusions, identified at the scale of the Variscan belt, including petalite- or spodumene-rich pegmatites, as well as Li-mica-rich pegmatites, for which the origin of mineralogical-chemical differences is not yet understood. Here, we provide cassiterite and columbite-group mineral (CGM) U-Pb ages along with oxide, mica and phosphate mineral compositions for Li-pegmatites from the Fregeneda-Almendra field in order to assess their petrogenesis and tectonic-magmatic context of emplacement. U-Pb geochronology indicates that petalite-rich and Li-mica-rich pegmatites were mostly emplaced sub-synchronously from 315 ± 6 to 308 ± 6 Ma, during strike-slip deformation and granitic magmatism within an anatectic dome bounding the pegmatite field. U-Pb data and pegmatite geographic zonation suggest that Li-pegmatites were sourced from buried equivalents of leucogranites and migmatites from the dome. Li-pegmatites experienced a complex crystallization including K-feldspar, petalite, topaz, Nb-Ta-Fe-Mn-rich cassiterite, amblygonite-group minerals (AGM) and CGM as early magmatic phases, followed by lepidolite for Li-mica-rich pegmatites. At the magmatic-hydrothermal transition, notably leading to the formation of Nb-Ta-Mn-Fe-poor cassiterite hosting CGM inclusions, earlier minerals were resorbed by muscovite and albite. A later F-rich hydrothermalism is locally reflected by zinnwaldite overgrowths on muscovite. Cassiterite, CGM and micas from petalite-rich pegmatites show lower Mn/Fe ratios and higher Ti contents, along with lower Zr-Ga contents for cassiterite, than that from Li-mica-rich pegmatites. Such behavior is consistent with a magmatic differentiation process whereby Ti content decreased and the degree of Mn-Fe geochemical fractionation and solubilities of Ga and Zr increased in the melts, possibly in relation with high fluorine activity. In Li-mica-rich pegmatites, AGM equilibrated with a melt with up to 2 wt% F, similar to that in equilibrium with lepidolite (1–3 wt%). In petalite-rich pegmatites, the relatively high F concentration of the melts equilibrated with AGM (≤ 1.5 wt% F) contrasts with the liquid equilibrated with muscovite (< 0.5 wt% F). This can be accounted for by muscovite crystallization after the exsolution of a F-rich aqueous phase at the magmatic-hydrothermal transition. Relatively similar F contents in the initial melts of petalite- and Li-mica-rich pegmatites support the hypothesis that the stability of lepidolite does not only involve high F but also a low H2O/F activity ratio. For the Fregeneda-Almendra Li-mica-rich pegmatites, this could be explained by a decrease of melt H2O solubility due to a relatively low pressure of emplacement.

We report the observation and analysis of the gain curve of amplified Kα x-ray emission from solutions of Mn(II) and Mn(VII) complexes using an x-ray free electron laser to create the 1s core-hole population inversion. We find spectra at amplification levels extending over 4 orders of magnitude until saturation. We observe bandwidths below the Mn 1s core-hole lifetime broadening in the onset of the stimulated emission. In the exponential amplification regime the resolution corrected spectral width of ∼1.7  eV FWHM is constant over 3 orders of magnitude, pointing to the buildup of transform limited pulses of ∼1  fs duration. Driving the amplification into saturation leads to broadening and a shift of the line. Importantly, the chemical sensitivity of the stimulated x-ray emission to the Mn oxidation state is preserved at power densities of ∼10^{20}  W/cm^{2} for the incoming x-ray pulses. Differences in signal sensitivity and spectral information compared to conventional (spontaneous) x-ray emission spectroscopy are discussed. Our findings build a baseline for nonlinear x-ray spectroscopy for a wide range of transition metal complexes in inorganic chemistry, catalysis, and materials science.

The paper investigates the Hoeffding–Sobol decomposition of homogeneous co-survival functions. For this class, the Choquet representation is transferred to the terms of the functional decomposition, and in addition to their individual variances, or to the superset combinations of those. The domain of integration in the resulting formulae is reduced in comparison with the already known expressions. When the function under study is the stable tail dependence function of a random vector, ranking these superset indices corresponds to clustering the components of the random vector with respect to their asymptotic dependence. Their Choquet representation is the main ingredient in deriving a sharp upper bound for the quantities involved in the tail dependograph, a graph in extreme value theory that summarizes asymptotic dependence.

Abstract Brannerite, UTi2O6 is reported to occur in various uraniferous deposits worldwide. Natural brannerite specimens are found in the amorphous state and are usually considered to be refractory to dissolution due to the formation of TiO2 passivation layer. In the present work, brannerite was synthesized by wet chemistry route, then characterized prior the development of multiparametric dissolution experiments. The evolution of U and Ti concentrations was followed in 0.1–2 mol/L H2SO4 solutions, for temperatures ranging from 25 to 80 °C, in the presence (or not) of 2.8 g/L of dissolved Fe(III). The dissolution of synthetic brannerite was congruent in the whole experimental domain. The formation of Ti-enriched secondary phase at the surface of the brannerite grains was not evidenced. The dissolution rate constants, activation energies and partial orders of the overall dissolution reaction relative to proton activity were determined in the presence (or absence) of Fe(III). The introduction of Fe(III) in sulfuric acid solutions increased the dissolution rate constant by 5 orders of magnitude and induced significant modifications of the apparent activation energy (from 71 ± 4 to 91 ± 6 kJ/mol) and of the partial order relative to proton activity (from 0.42 ± 0.09 to 0.84 ± 0.08). This study suggested that the uncongruency of the brannerite dissolution and the changes usually observed in the rate-controlling step with temperature could be linked to the loss of the crystal structure in natural samples.