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This report (I) aims to investigate defect behavior during the growth of heavily phosphorus (P)-doped Czochralski silicon (HP-Cz-Si) crystals. The defects and P chemical states in as-grown crystals with a resistivity of 0.6 mΩ cm and the wafers annealed at around 600 °C were evaluated by transmission electron microscopy and hard x-ray electron spectroscopy (HAXPES). Micro-dislocation loops (MDLs) were observed in the bottom portion of the crystal, and larger stacking faults (SFs), including complex dislocation clusters, were observed in the middle portion. HAXPES revealed two different P states, P1 and P2. P1 was attributed to a substitutional P (Ps). The P2 present in as-grown crystals was found to be electrically active, while the newly formed P2 after annealing was electrically inactive, indicating that they are in different states. HAXPES evaluation of HP-Cz-Si after electron irradiation showed similar behavior to P2 after annealing, suggesting that P-vacancy (V) clusters are formed when the crystals are held at temperatures below 600 °C during crystal growth. Combining the experimental results with our theoretical analysis in the report (II) based on density functional theory calculations, we identified the following defect formation mechanisms. Interstitial P (Pi) atoms introduced at the melting point become supersaturated during cooling to 600 °C, and MDLs are generated by the aggregation of Si self-interstitials (Is) released through a position exchange from Pi to Ps. In crystal portions with a long residence time below 600 °C, supersaturated Ps transforms into P–V clusters, and Is generated simultaneously are absorbed by the MDLs, which grow into SFs containing dislocation clusters. [ABSTRACT FROM AUTHOR]

We investigate the temporal correlation between very-high-frequency (VHF, at frequencies of the order of 10–100 MHz), ultrahigh-frequency (UHF, at frequencies within 1–6 GHz), and x-ray (with photon energies more than 10 keV) emissions, which accompany the development of a high-voltage discharge initiated in a long gap at voltages up to 1 MV. The x-ray and UHF emissions are found to emerge starting approximately from the prepulse current onset observed before the discharge gap breakdown and both gradually decay coming to this instant. The UHF emission spectrum is represented with frequencies up to 6 GHz, with the highest spectral power being achieved within 1–2 GHz. The radio emission power drops sharply at frequencies below 1 GHz and increases closer to 150 MHz with the highest spectral power of VHF radiation being reached within 60–90 MHz. The VHF emission can appear before the discharge current and UHF emission onsets in the form of 100-ns-long prepulses, and its intensity significantly increases as the UHF emission starts. The analysis of the temporal correlation between x rays, VHF, and UHF radiations, discharge current, and voltage waveforms indicates that the generation mechanisms of the discharge electromagnetic radiations are difficult to be interpreted in terms of the developing or colliding streamer concepts. [ABSTRACT FROM AUTHOR]

A fraction of the active supermassive black holes at the centers of galaxies in our Universe are capable of launching extreme kiloparsec-long relativistic jets. These jets are known multiband (radio to γ-ray) and multimessenger (neutrino) emitters, and some of them have been monitored over decades at all accessible wavelengths. However, several open questions remain unanswered about the processes powering these highly energetic phenomena. These jets intrinsically produce soft-to-hard X-ray emission that extends from E > 0.1 keV up to E > 100 keV, and simultaneous broadband X-ray coverage, combined with excellent timing and imaging capabilities, is required to uncover the physics of jets. Indeed, truly simultaneous soft-to-hard X-ray coverage, in synergy with current and upcoming high-energy facilities (such as IXPE, COSI, CTAO, etc.) and neutrino detectors (e.g., IceCube), would enable us to disentangle the particle population responsible for the high-energy radiation from these jets. A sensitive hard X-ray survey (F20-80 keV < 10-15erg cm-2 s-1) could unveil the bulk of their population in the early Universe. Acceleration and radiative processes responsible for the majority of their X-ray emission would be pinned down by microsecond timing capabilities at both soft and hard X-rays. Furthermore, imaging jet structures for the first time in the hard X-ray regime could unravel the origin of their high-energy emission. The proposed Probe-class mission concept High Energy X-ray Probe (HEX-P) combines all these required capabilities, making it the crucial next-generation X-ray telescope in the multi-messenger, time-domain era. HEX-P will be the ideal mission to unravel the science behind the most powerful accelerators in the Universe. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles offer many exciting possibilities in biomedicine, from cell imaging to cancer treatment. One of the currently researched nanoparticles are magnetosomes, magnetite nanoparticles of high chemical purity synthesized by magnetotactic bacteria. Despite their therapeutic potential, very little is known about their degradation in human cells, and even less so of their degradation within tumours. In an effort to explore the potential of magnetosomes for cancer treatment, we have explored their degradation process in a 3D human lung carcinoma model at the subcellular level and with nanometre scale resolution. We have used state of the art hard X-ray probes (nano-XANES and nano-XRF), which allow for identification of distinct iron phases in each region of the cell. Our results reveal the progression of magnetite oxidation to maghemite within magnetosomes, and the biosynthesis of magnetite and ferrihydrite by ferritin. [ABSTRACT FROM AUTHOR]

The Biomedical Imaging and Therapy facility of the Canadian Light Source comprises two beamlines, which together cover a wide X‐ray energy range from 13 keV up to 140 keV. The beamlines were designed with a focus on synchrotron applications in preclinical imaging and veterinary science as well as microbeam radiation therapy. While these remain a major part of the activities of both beamlines, a number of recent upgrades have enhanced the versatility and performance of the beamlines, particularly for high‐resolution microtomography experiments. As a result, the user community has been quickly expanding to include researchers in advanced materials, batteries, fuel cells, agriculture, and environmental studies. This article summarizes the beam properties, describes the endstations together with the detector pool, and presents several application cases of the various X‐ray imaging techniques available to users. [ABSTRACT FROM AUTHOR]

Recently, material strength measurements have been often performed by combining mechanical material characterization and lattice diffraction experiments using hard X-rays. When X-ray diffraction experiments are performed simultaneously with tensile tests, plastic deformation due to stress can be analyzed at the lattice level. Although this evaluation procedure is suitable for materials such as metals, it does not provide information on molecular state changes and stress-induced electronic state transitions in polymer materials. Combined with an evaluation system in the electron energy band involved in chemical bonding during the tensile stress application, the systems would advance our understanding of adhesion states such as interfaces in polymer materials and composites. Here, we developed a MEMS-based system aimed at implementing a Raman spectroscopy imaging system and a stress control system on a soft X-ray absorption spectroscopy and photoelectron spectroscopy microscopy (PEEM) system. We prepared two types of MEMS device: a double-sided beam structure device and a three-point tensile testing device. A three-point tensile MEMS was integrated into a micro-Raman spectroscopy system to perform micro-Raman spectroscopy measurements during the tensile testing of a silicon beam. As for the double-sided beam structure MEMS, it was successfully introduced into the synchrotron radiation PEEM system and its operation was confirmed in vacuum. [ABSTRACT FROM AUTHOR]

Utilizing four archival X-ray data sets taken with the Hard X-ray Detector onboard Suzaku , timing studies were performed on three magnetars, 1E 1841−045 (observed in 2006), SGR 0501+4516 (2008), and 1RXS J170849.0−400910 (2009 and 2010). Their pulsations were reconfirmed, typically in an energy range of 12–50 keV. The 11.783 s pulses of 1E 1841−045 and those of SGR 0501+4516 at 5.762 s were periodically phase modulated, with a long period of |$\approx 23.4$| and |$\approx 16.4$|  ks, respectively. The pulse-phase modulation was also observed, at |$\approx 46.5$|  ks, from two data sets of 1RXS J170849.0−400910. In all these cases, the modulation amplitude was 6 per cent to 16 per cent of the pulse cycle. Including previously confirmed four objects, this characteristic timing behaviour is now detected from seven magnetars in total, and interpreted as a result of free precession of neutron stars that are deformed to an asphericity of |$\sim 10^{-4}$|⁠. Assuming that the deformation is due to magnetic stress, these magnetars are inferred to harbour toroidal magnetic fields of |$B_{\rm t}\sim 10^{16}$|  G. By comparing the estimated |$B_{\rm t}$| of these objects with their poloidal dipole field |$B_{\rm d}$|⁠ , the |$B_{\rm t}/B_{\rm d}$| ratio is found to increase with their characteristic age. Therefore, the toroidal fields of magnetars are likely to last longer than their poloidal fields. This explains the presence of some classes of neutron stars that have relatively weak |$B_{\rm d}$| but are suspected to hide strong |$B_{\rm t}$| inside them. [ABSTRACT FROM AUTHOR]

One of the most promising methods to measure the spin of an accreting black hole is fitting the broad iron K |$\alpha$| line in the X-ray spectrum. The line profile also depends on the geometry of the hard X-ray emitting corona. To put constraints on the black hole spin and corona geometry, it is essential to understand how do they affect the iron K |$\alpha$| line emissivity profile. In this work, we present calculations of the illumination and the iron K |$\alpha$| emissivity profiles performed with the Monte Carlo GR radiative transfer code monk. We focus on distinction between the illumination and emissivity profiles, which is in most previous studies neglected. We show that especially for the case of black hole X-ray binaries (BHXRBs), the difference is very large. For active galactic nuclei (AGNs), the emissivity profile has a more similar shape as the illumination profile, but it is notably steeper in the innermost region within a few gravitational radii. We find out that the different behaviour between AGN and BHXRB discs is due to the different energy spectra of the illuminating radiation. This suggests that the emissivity profile of the iron K |$\alpha$| line cannot be determined by black hole spin and corona geometry alone and the energy spectrum of the illuminating radiation has to be taken into account. We also examined the effect of including the self-irradiation, and find it to be more important than the corona emission in BHXRBs. [ABSTRACT FROM AUTHOR]

Most of the |$\gamma$| -ray sources in the Fermi-LAT 14-yr source catalogue are associated with pulsars and blazars. However, unveiling the nature of the still unassociated |$\gamma$| -ray sources is important for the understanding of high energy emission mechanisms in astrophysical objects. This work presents a comprehensive study towards the region covered by the Fermi source 4FGL J1846.9 |$-$| 0227, previously suggested to be a blazar and a massive protostar. Using multiwavelength observations, we analysed several astrophysical objects in the region as possible counterparts of the Fermi-LAT source. Having discarded most of them after a detailed and comprehensive analysis, we suggest that the most likely candidate to be such a counterpart is IRAS 18443 |$-$| 0231, a likely protoplanetary nebula. We found that the radio continuum emission at 3 GHz of IRAS 18443 |$-$| 0231 shows a compact source related to faint emission with jet-like morphology. Additionally, we identified an associated redshifted CO molecular outflow. Using data from several catalogues, we obtained radio spectral index values ranging from |$-$| 0.57 to |$-$| 0.39 for IRAS 18443 |$-$| 0231, indicating synchrotron emission due to particles accelerated by the jets. We point out that these jets could explain the |$\gamma$| -ray emission through mechanisms such as proton–proton collisions and relativistic bremsstrahlung. IRAS 18443 |$-$| 0231, lying almost at the centre of the Fermi confidence ellipse and related to the hard X-ray source 4XMM J184700.4 |$-$| 022752, would be the first association between a protoplanetary nebula and |$\gamma$| -ray emission. [ABSTRACT FROM AUTHOR]

Production of hard X-ray via inverse Compton scattering at photon energies below 100 keV range aimed at potential applications in medicine and material research is reported. Experiments have been performed at the Brookhaven National Laboratory, Accelerator Test Facility, employing the counter collision of a 70 MeV, 0.3 nC electron beam with a near infra-red Nd: YAG laser (1064 nm wavelength) pulse containing ~ 100 mJ in a single shot basis. The radiation distribution of the scattered photon beam is assessed to be sufficiently quasi monochromatic to produce clear contrast from the Au K- edge at 80.7 keV. [ABSTRACT FROM AUTHOR]

In this work, we present the results of a detailed X-ray spectral analysis of the brightest active galactic nuclei (AGNs) detected in the XMM–Newton 1.75 Ms Ultra Narrow Deep Field. We analysed 23 AGNs that have a luminosity range of |$\sim 10^{42} {\!-\!} 10^{46}\, \rm {erg}\, \rm {s}^{-1}$| in the |$2 {\!-\!} 10\, \rm {keV}$| energy band, redshifts up to 2.66, and |$\sim 10\,000$| X-ray photon counts in the |$0.3{ \!-\! }10\, \rm {keV}$| energy band. Our analysis confirms the 'Iwasawa – Taniguchi effect,' an anticorrelation between the X-ray luminosity (⁠|$L_x$|⁠) and the Fe – k |$\alpha$| equivalent width (⁠|${\rm EW}_{\rm Fe}$|⁠) possibly associated with the decreasing of the torus covering factor as the AGN luminosity increases. We investigated the relationship among black hole mass (⁠|$M_{\rm BH}$|⁠), |$L_x$|⁠ , and X-ray variability, quantified by the Normalized Excess Variance (⁠|$\sigma ^2_{\rm rms}$|⁠). Our analysis suggest an anticorrelation in both |$M_{\rm BH} - \sigma ^2_{\rm rms}$| and |$L_x- \sigma ^2_{\rm rms}$| relations. The first is described as |$\sigma ^2_{\rm rms} \propto M^{-0.26 \pm 0.05}_{\rm BH}$|⁠ , while the second presents a similar trend with |$\sigma ^2_{\rm rms} \propto L_{x}^{-0.31 \pm 0.04}$|⁠. These results support the idea that the luminosity – variability anticorrelation is a byproduct of an intrinsic relationship between the BH mass and the X-ray variability, through the size of the emitting region. Finally, we found a strong correlation among the Eddington ratio (⁠|$\lambda _{\rm Edd}$|⁠), the hard X-ray photon index (⁠|$\Gamma$|⁠), and the illumination factor |$\log (A)$|⁠ , which is related to the ratio between the number of Compton scattered photons and the number of seed photons. The |$\log (\lambda _{\rm Edd})-\Gamma -\log (A)$| plane could arise naturally from the connection between the accretion flow and the hot corona. [ABSTRACT FROM AUTHOR]

A powerful and flexible hard x-ray (HXR) camera has been recently installed and tested on the WEST tokamak (CEA, France) in collaboration with the Princeton Plasma Physics Laboratory. The diagnostic is a pinhole camera fielded with a 2D pixel detector equipped with a 1 mm thick CdTe sensor. The novelty of this diagnostic technique is the detector's capability of adjusting the threshold energy at the pixel level. This innovation provides great flexibility in the energy configuration, allowing simultaneous space, energy, and time resolved x-ray measurements. The novel camera has been used to measure the core radiation from non-Maxwellian (fast) electrons accelerated by Lower Hybrid (LH) waves and also the beam–target emission of tungsten in the divertor region produced by fast electron losses interacting with the target. In addition, anisotropic hard x-ray emission has been detected for the first time at the WEST core and edge plasma, with opposite toroidal intensity trends. Experimental vertical and toroidal HXR profiles have been successfully reproduced with the LH code LUKE. [ABSTRACT FROM AUTHOR]

The SPARC tokamak will be equipped with a hard X-ray (HXR) monitor system capable of measuring the bremsstrahlung emission from runaway electrons with photon energies in excess of about 100 keV. This diagnostic will detect the formation of runaway electron beams during plasma start-up and inform the plasma control system to terminate the discharge early to protect the machine. In this work, we present a 0D estimate of the HXR emission in SPARC during plasma start-up. Then we discuss the characterization of a prototype of the HXR monitor. The detector mounts a 1 × 1-in.2 LaBr3 inorganic scintillator coupled with a photomultiplier tube and has been tested with γ-ray sources to find its dynamic range. Finally, two possible modes of operation for spectroscopic and current mode measurements on SPARC are proposed. [ABSTRACT FROM AUTHOR]

The effect of non-Planckian radiation source is investigated in pure and 2% silicon doped polystyrene ablator foils by using radiation hydrodynamic simulations, covered over a broad range of drive parameters namely, its strength and hard or M-band x-ray contribution α (ratio of externally imposed Gaussian to original Planck energy density). The spatiotemporal dynamics of shock propagation indicates a large change in rear surface conditions, measured in terms of density and material temperature evolution with the increasing values of α and doping. Different scaling relations, motivated by the generalization of stationary x-ray driven ablation and strong shock theory, are proposed for different variables of interest that suggest a sharp and slow rise with strength and α of incident source, respectively. Just a 2% of silicon doping is able to increase the shock speed by ∼ 9 % and, to reduce the shock breakout and the maximum preheating temperature by ∼ 40 % and ∼ 50 % , respectively for extreme drive conditions. A thorough understanding of the results is important in interpreting the present inertial confinement fusion experiments and proposing the next generation polystyrene based implosion designs for National Ignition Facility. [ABSTRACT FROM AUTHOR]

Halide perovskite single crystals (SCs) have attracted much attention for their application in high‐performance x‐ray detectors owing to their desirable properties, including low defect density, high mobility–lifetime product (μτ), and long carrier diffusion length. However, suppressing the inherent defects in perovskites and overcoming the ion migration primarily caused by these defects remains a challenge. This study proposes a facile process for dipping Cs0.05FA0.9MA0.05PbI3 SCs synthesized by a solution‐based inverse temperature crystallization method into a 2‐phenylethylammonium iodide (PEAI) solution to reduce the number of defects, inhibit ion migration, and increase x‐ray sensitivity. Compared to conventional spin coating, this simple dipping process forms a two‐dimensional PEA2PbI4 layer on all SC surfaces without further treatment, effectively passivating all surfaces of the inherently defective SCs and minimizing ion migration. As a result, the PEAI‐treated perovskite SC‐based x‐ray detector achieves a record x‐ray sensitivity of 1.3 × 105 μC Gyair−1 cm−2 with a bias voltage of 30 V at realistic clinical dose rates of 1–5 mGy s−1 (peak potential of 110 kVp), which is 6 times more sensitive than an untreated SC‐based detector and 3 orders of magnitude more sensitive than a commercial α‐Se‐based detector. Furthermore, the PEAI‐treated‐perovskite SC‐based x‐ray detector exhibits a low detection limit (73 nGy s−1), improved x‐ray response, and clear x‐ray images by a scanning method, highlighting the effectiveness of the PEAI dipping approach for fabricating next‐generation x‐ray detectors. [ABSTRACT FROM AUTHOR]

The buried interface tens of nanometers beneath the solid-liquid junction is crucial for photocarrier extraction, influencing the overall efficiency of photoelectrochemical devices. Precise characterization of the interfacial properties is essential for device optimization but remains challenging. Here, we directly probe the in situ transformation of a CuxO interlayer at the NiO/n-Si interface by hard X-ray photoelectron spectroscopy. It is found that Cu(I) in the CuxO interlayer gradually transforms to Cu(II) with air exposure, forming an energetically more favorable interface and improving photoanode's efficiency. Based on this finding, a reactive e-beam evaporation process is developed for the direct deposition of a CuO interlayer, achieving a half-cell solar-to-hydrogen efficiency of 4.56% for the optimized NiO/CuO/n-Si heterojunction photoanode. Our results highlight the importance of precision characterization of interfacial properties with advanced hard X-ray photoelectron spectroscopy in guiding the design of efficient solar water-splitting devices. The buried interface beneath the solid-liquid junction is crucial for photoelectrochemical device efficiency and requires precise characterization for optimization. Here the authors probe the in situ transformation of a CuxO interlayer at the NiO/n-Si interface by hard X-ray photoelectron spectroscopy and improve solar-to-hydrogen efficiency to 4.56%. [ABSTRACT FROM AUTHOR]

In this paper, the ferroelectric properties of TiN/Ti/Si:HfO2/TiN stacks are shown to be modulated by the Ti oxygen scavenging layer, leading to improved remanent polarization and wake-up at low switching fields. Hard x-ray photoelectron spectroscopy is used to measure the oxygen vacancy (VO) concentration in Si-doped HfO2 based capacitors. This VO engineered ferroelectric stack is then assessed at the wafer scale within 16 kbit 1T-1C FeRAM arrays integrated into 130 nm CMOS. The introduction of a Ti oxygen scavenging layer at the top interface of Si:HfO2-based BEOL-integrated metal/ferroelectric/metal capacitors enhances their ferroelectric (FE) behavior (+100% remanent polarization 2.Pr), confirming the positive role of modest concentrations of VO in orthorhombic phase crystallization at low thermal budgets. It is statistically demonstrated at 16 kbit array level that VO-rich FE Si:HfO2 facilitates 2.5 V FeRAM array operation with improved memory window. The field cycling dependence of the memory window is correlated with the VO concentration, and an endurance of 108 cycles is measured at the array level. [ABSTRACT FROM AUTHOR]

X‐ray detectors have obtained great attention in medical diagnostics, security checks, and space exploration. However, ion migration of X‐ray detectors results in dark current drift, low signal‐to‐noise ratio, and degradation of detection performance. Here, ion migration properties of Li2ZrTeO6 and ZrTe3O8 are comprehensively investigated by theoretical analysis and experimental results. ZrTe3O8 single crystal exhibits a high migration barrier of O2− ion (1.89 eV), a high ion activation energy (992.6 meV), and an ultralow dark current drift (3.16 × 10−9 nA cm−1 s−1 V−1) due to the absence of Li+ cations and the disconnecting of adjacent ZrO6 octahedra, which is better than Li2ZrTeO6 single crystal. These results show that the absence of low atomic number elements and the disconnecting of adjacent octahedra in crystal structure can inhibit ion migration essentially. Owing to a high resistivity, a high mobility lifetime product, suppressed ion migration, and the lone‐pair electrons enhancement effect of detection performance for Te4+ cations, ZrTe3O8 X‐ray detector shows a high sensitivity of 348 µC Gy−1 cm−2 and an ultralow detection limit of 15.4 nGyair s−1. This work proposes an effective strategy to inhibit ion migration and proves the enhancement effect of detection performance for the cations containing lone‐pair electrons. [ABSTRACT FROM AUTHOR]

Synchronous spatiotemporal measurements of hard X rays emitted during the development of a high-voltage discharge at voltages of ~1 MV in half-meter open air gaps have been carried out for the first time. Using an array of scintillation detectors with lead diaphragms and the nanosecond photography of the discharge in the intrinsic luminescence, it has been shown that X rays are emitted in the discharge development stage when numerous brightly luminescent plasma channels are formed in the entire discharge gap and the discharge current with an amplitude of hundreds of amperes flows. It has been found that the emission of X rays (photons with energies above 5 keV) can start almost synchronously in the entire discharge gap, including the cathode and anode regions, near-cathode and near-anode regions, and the middle of the discharge gap. The statistical distributions of the total power and the number of the observed X-ray flashes along the discharge gap have been obtained. [ABSTRACT FROM AUTHOR]

The SRG/eROSITA All-Sky Survey (eRASS) allows for the creation of a complete sample of X-ray dim isolated neutron stars (XDINSs), which will significantly facilitate the study of their population properties, evolution, and connection to other families of isolated neutron stars (INSs). In this work, we conduct a systematic search for XDINSs on the eROSITA western Galactic hemisphere down to an X-ray flux limit of 10−13 erg s−1 cm−2 and discuss the resulting candidate sample. Consistently with the properties of the known XDINSs, we selected all eRASS sources possessing a soft X-ray spectral distribution and that are unlikely to be associated with optical or infrared sources. Our selection criteria allowed us to recover all known XDINSs and previously proposed candidates. In addition, we put forward 33 new candidate members for dedicated follow-up identification campaigns. We found the resulting candidate sample to be about 30–50% complete, mainly due to source confusion and the stringent cross-matching criteria adopted to select the most promising candidates for immediate follow-up investigation. The candidates of the sample presented here can be broadly divided into two groups: 13 rather soft and 20 hot and somewhat hard X-ray emitters. Interestingly, the remarkably thermal nature of the candidates in the first group as well as their spatial distribution, lack of known counterparts, and absence of significant flux variability agree well with the properties of other confirmed thermally emitting INSs. For the candidates in the second group, the current observational data do not allow one to discern between rotation-powered or recycled pulsars, cataclysmic variables, or quiescent neutron stars in binary systems or even to rule out an extragalactic nature. On the basis of population synthesis and the estimated source completeness of the search, we expect that between one and three new XDINSs are among the already singled-out list of XDINS candidates – a long-sought increase in the proposed number of members of this elusive class of X-ray emitters. [ABSTRACT FROM AUTHOR]

Context. Ultra-fast outflows (UFOs) have been revealed in a large number of active galactic nuclei (AGN) in the past two decades. Their extreme velocities and high ionization states make them a promising candidate for AGN feedback on the evolution of the host galaxy. However, their exact underlying driving mechanism is not yet fully understood. Aims. Given that the variability of UFOs may be used to distinguish among different launching mechanisms, we aim to search for and characterize the responses of the UFO properties to the variable irradiating luminosity. Methods. We perform a high-resolution time- and flux-resolved spectroscopy of archival XMM-Newton observations on six highly accreting narrow-line Seyfert 1 (NLS1) galaxies, selected by UFO detection and sufficient exposure times. The state-of-the-art methods of the blind Gaussian line scan and photoionization model scan are used to identify UFO solutions. We search for ionized winds and investigate the structure of ionized winds and their responses to the luminosity variations. The location, density, and kinetic energy of UFOs are estimated as well. Results. The powerful photoionization model scan reveals three previously unreported UFOs in RE J1034+396, PG 1244+026 and I ZW 1 with a detection significance above 3σ, and two new warm absorbers (WAs) in RE J1034+396. Five out of six (83%) AGN in our sample host multi-phase ionized winds, where outflows in I ZW 1 are energy-conserved. The relatively low-ionization entrained UFOs are discovered in four (66%) AGN of our sample, supporting the shocked outflow interpretation for ionized winds in AGN. We notice that two out of seven (28%) UFOs in our sample seem to respond to the radiation field and three (43%) UFOs hint at a radiatively accelerated nature, requiring further observations. Combined with published works, we do not find any correlations between UFO responses and AGN properties except for a tentative (∼1.8σ) anti-correlation between the UFO acceleration and the Eddington ratio, to be confirmed by further observations and an enlarged sample. The kinetic energy of UFOs, mostly detected in soft X-rays, is found to have a large uncertainty. We, therefore, cannot conclude whether soft X-ray UFOs have sufficient energy to drive the AGN feedback, although they are very promising based on some reasonable assumptions. The primary UFO in I ZW 1 (detected in the hard X-ray) is the only case in our sample to possess conclusively sufficient energy to affect the host galaxy. [ABSTRACT FROM AUTHOR]

Context. Massive star winds are known to be responsible for X-ray emission arising from wind plasma heated by the strong shocks up to temperatures of 106–107 K in the case of colliding wind binaries. The investigation of X-ray emission from massive stars thus constitutes a valuable tool for identifying binaries, which is otherwise a difficult task using classical techniques. Aims. We investigated thermal and nonthermal X-ray emission from the massive O-type star HD 93250 to unveil its binary orbital parameters independently. Methods. To meet our goal, we analyzed X-ray data obtained with European Photon Imaging Camera on board XMM-Newton spanning over ~19 yr. Additionally, we analyzed NuSTAR observations of HD 93250 taken at various epochs. Results. We determine the variability timescale of the X-ray emission to be 193.8±1.3d, in full agreement with the 194.3±0.4d period derived from the astrometric orbit. The X-ray spectrum of HD 93250 is well explained by a three-temperature thermal plasma emission model with temperatures of 0.26, 1.0, and 3.3 keV. The resulting X-ray flux varies in compliance with the typical colliding wind emission from eccentric massive binaries where it enhances near periastron passage and decreases gradually close to apastron in proportion to the inverse of the binary separation. The periastron-to-apastron X-ray emission ratio points to an eccentricity range of 0.20–0.25, once again in agreement with the previously determined astrometric orbit. Finally, we do not detect any hard X-ray emission attributable to nonthermal emission above 10 keV. Conclusions. Given the derived plasma temperature, the strong phase-locked variability, and the significant over-luminosity in X-rays, we establish that the X-ray emission from HD 93250 is dominated by the colliding-wind region. Our results lend support to the idea that X-ray time analysis of massive stars constitutes a relevant tool for investigating their multiplicity and for extracting relevant information on their basic orbital parameters – such as period and eccentricity – independently of any orbital solution derived from classical techniques. [ABSTRACT FROM AUTHOR]

We report on the detection of type-C quasi-periodic oscillations during the initial stages of the outburst of Swift J1727.8–1613 in 2023. Using data of the INTEGRAL observatory along with the data of the Mikhail PavlinskyART-XC telescope on board Spektr-RG and X-ray Telescope (XRT) of the Neil Gehrels Swift observatory the fast growth of the quasi-periodic oscillations (QPO) frequency was traced. We present a hard X-ray light curve that covers the initial stages of the 2023 outburst – the fast rise and plateau – and demonstrate that the QPO frequency was stable during the plateau. The switching from type-C to type-B QPO was detected with the beginning of the source flaring activity. We have constructed a broad-band spectrum of Swift J1727.8−1613 and found an additional hard cutoff power-law spectral component extending at least up to 250 keV. Finally, we have obtained an upper limit on the hard X-ray flux at the beginning of the optical outburst and estimated the delay of the hard X-ray outburst with respect to the optical one. [ABSTRACT FROM AUTHOR]

Unconventional superconductivity often couples to other electronic orders in a cooperative or competing fashion. Identifying external stimuli that tune between these two limits is of fundamental interest. Here, we show that strain perpendicular to the copper-oxide planes couples directly to the competing interaction between charge stripe order and superconductivity in La1.88Sr0.12CuO4 (LSCO). Compressive c-axis pressure amplifies stripe order within the superconducting state, while having no impact on the normal state. By contrast, strain dramatically diminishes the magnetic field enhancement of stripe order in the superconducting state. These results suggest that c-axis strain acts as tuning parameter of the competing interaction between charge stripe order and superconductivity. This interpretation implies a uniaxial pressure-induced ground state in which the competition between charge order and superconductivity is reduced. Tuning superconductivity and its interplay with other phases in cuprates yields insights into the underlying physics of this material class. Here, the authors performed a hard x-ray diffraction experiment on La1.88Sr0.12CuO4 showing that uniaxial pressure along the c-axis acts as a direct tuning parameter of the competition between superconductivity and charge order. [ABSTRACT FROM AUTHOR]

Unconventional superconductivity often couples to other electronic orders in a cooperative or competing fashion. Identifying external stimuli that tune between these two limits is of fundamental interest. Here, we show that strain perpendicular to the copper-oxide planes couples directly to the competing interaction between charge stripe order and superconductivity in La1.88Sr0.12CuO4 (LSCO). Compressive c-axis pressure amplifies stripe order within the superconducting state, while having no impact on the normal state. By contrast, strain dramatically diminishes the magnetic field enhancement of stripe order in the superconducting state. These results suggest that c-axis strain acts as tuning parameter of the competing interaction between charge stripe order and superconductivity. This interpretation implies a uniaxial pressure-induced ground state in which the competition between charge order and superconductivity is reduced. Tuning superconductivity and its interplay with other phases in cuprates yields insights into the underlying physics of this material class. Here, the authors performed a hard x-ray diffraction experiment on La1.88Sr0.12CuO4 showing that uniaxial pressure along the c-axis acts as a direct tuning parameter of the competition between superconductivity and charge order. [ABSTRACT FROM AUTHOR]

Unconventional superconductivity often couples to other electronic orders in a cooperative or competing fashion. Identifying external stimuli that tune between these two limits is of fundamental interest. Here, we show that strain perpendicular to the copper-oxide planes couples directly to the competing interaction between charge stripe order and superconductivity in La1.88Sr0.12CuO4 (LSCO). Compressive c-axis pressure amplifies stripe order within the superconducting state, while having no impact on the normal state. By contrast, strain dramatically diminishes the magnetic field enhancement of stripe order in the superconducting state. These results suggest that c-axis strain acts as tuning parameter of the competing interaction between charge stripe order and superconductivity. This interpretation implies a uniaxial pressure-induced ground state in which the competition between charge order and superconductivity is reduced. Tuning superconductivity and its interplay with other phases in cuprates yields insights into the underlying physics of this material class. Here, the authors performed a hard x-ray diffraction experiment on La1.88Sr0.12CuO4 showing that uniaxial pressure along the c-axis acts as a direct tuning parameter of the competition between superconductivity and charge order. [ABSTRACT FROM AUTHOR]

Unconventional superconductivity often couples to other electronic orders in a cooperative or competing fashion. Identifying external stimuli that tune between these two limits is of fundamental interest. Here, we show that strain perpendicular to the copper-oxide planes couples directly to the competing interaction between charge stripe order and superconductivity in La1.88Sr0.12CuO4 (LSCO). Compressive c-axis pressure amplifies stripe order within the superconducting state, while having no impact on the normal state. By contrast, strain dramatically diminishes the magnetic field enhancement of stripe order in the superconducting state. These results suggest that c-axis strain acts as tuning parameter of the competing interaction between charge stripe order and superconductivity. This interpretation implies a uniaxial pressure-induced ground state in which the competition between charge order and superconductivity is reduced. Tuning superconductivity and its interplay with other phases in cuprates yields insights into the underlying physics of this material class. Here, the authors performed a hard x-ray diffraction experiment on La1.88Sr0.12CuO4 showing that uniaxial pressure along the c-axis acts as a direct tuning parameter of the competition between superconductivity and charge order. [ABSTRACT FROM AUTHOR]

In the scope of the latest upgrade of the Swiss Light Source, five hard X‐ray beamlines will be constructed or rebuilt. To use synergies between these beamline projects, a concept is developed here for hard X‐ray beamlines that is tailored to the new storage ring. Herein, this concept is described from the source, via the front end, to the beamline optics. The latter will be outlined in detail, including a new and modular concept for hard X‐ray monochromators, focusing optics and heat‐load management. With a simple, easy‐to‐operate and robust beamline design, the new beamlines will greatly profit from the increased brilliance of the new storage ring. The performance increase is up to four orders of magnitude, while the beamline concept allows for the broad application of experimental techniques, from propagation‐based methods, such as phase‐contrast tomography, to imaging techniques with nanometre resolution. At the same time, spectroscopy experiments are possible as well as high‐performance serial X‐ray crystallography. [ABSTRACT FROM AUTHOR]

X‐ray gas monitors (XGMs) are operated at the European XFEL for non‐invasive single‐shot pulse energy measurements and average beam‐position monitoring. The underlying measurement principle is the photo‐ionization of rare gas atoms at low gas pressures and the detection of the photo‐ions and photo‐electrons created. These are essential for tuning and sustaining self‐amplified spontaneous emission (SASE) operation, machine radiation safety, and sorting single‐shot experimental data according to pulse energy. In this paper, the first results from XGM operation at photon energies up to 30 keV are presented, which are far beyond the original specification of this device. Here, the Huge Aperture MultiPlier (HAMP) is used for single‐shot pulse energy measurements since the standard X‐ray gas monitor detectors (XGMDs) do not provide a sufficient signal‐to‐noise ratio, even at the highest operating gas pressures. A single‐shot correlation coefficient of 0.98 is measured between consecutive XGMs operated with HAMP, which is as good as measuring with the standard XGMD detectors. An intra‐train non‐linearity of the HAMP signal is discovered, and operation parameters to mitigate this effect are studied. The upper repetition rate limit of HAMP operation at 2.25 MHz is also determined. Finally, the possibilities and limits for future XGM operation at photon energies up to 50 keV are discussed. [ABSTRACT FROM AUTHOR]

Imaging energy filters in photoelectron microscopes and momentum microscopes use spherical fields with deflection angles of 90°, 180° and even 2 × 180°. These instruments are optimized for high energy resolution, and exhibit image aberrations when operated in high transmission mode at medium energy resolution. Here, a new approach is presented for bandpass‐filtered imaging in real or reciprocal space using an electrostatic dodecapole with an asymmetric electrode array. In addition to energy‐dispersive beam deflection, this multipole allows aberration correction up to the third order. Here, its use is described as a bandpass prefilter in a time‐of‐flight momentum microscope at the hard X‐ray beamline P22 of PETRA III. The entire instrument is housed in a straight vacuum tube because the deflection angle is only 4° and the beam displacement in the filter is only ∼8 mm. The multipole is framed by transfer lenses in the entrance and exit branches. Two sets of 16 different‐sized entrance and exit apertures on piezomotor‐driven mounts allow selection of the desired bandpass. For pass energies between 100 and 1400 eV and slit widths between 0.5 and 4 mm, the transmitted kinetic energy intervals are between 10 eV and a few hundred electronvolts (full width at half‐maximum). The filter eliminates all higher or lower energy signals outside the selected bandpass, significantly improving the signal‐to‐background ratio in the time‐of‐flight analyzer. [ABSTRACT FROM AUTHOR]

Nanoscale structural and electronic heterogeneities are prevalent in condensed matter physics. Investigating these heterogeneities in 3D has become an important task for understanding material properties. To provide a tool to unravel the connection between nanoscale heterogeneity and macroscopic emergent properties in magnetic materials, scanning transmission X‐ray microscopy (STXM) is combined with X‐ray magnetic circular dichroism. A vector tomography algorithm has been developed to reconstruct the full 3D magnetic vector field without any prior noise assumptions or knowledge about the sample. Two tomographic scans around the vertical axis are acquired on single‐crystalline Nd2Fe14B pillars tilted at two different angles, with 2D STXM projections recorded using a focused 120 nm X‐ray beam with left and right circular polarization. Image alignment and iterative registration have been implemented based on the 2D STXM projections for the two tilts. Dichroic projections obtained from difference images are used for the tomographic reconstruction to obtain the 3D magnetization distribution at the nanoscale. [ABSTRACT FROM AUTHOR]

Nanotomography with hard X‐rays is a widely used technique for high‐resolution imaging, providing insights into the structure and composition of various materials. In recent years, tomographic approaches based on simultaneous illuminations of the same sample region from different angles by multiple beams have been developed at micrometre image resolution. Transferring these techniques to the nanoscale is challenging due to the loss in photon flux by focusing the X‐ray beam. We present an approach for multi‐beam nanotomography using a dual‐beam Fresnel zone plate (dFZP) in a near‐field holography setup. The dFZP generates two nano‐focused beams that overlap in the sample plane, enabling the simultaneous acquisition of two projections from slightly different angles. This first proof‐of‐principle implementation of the dual‐beam setup allows for the efficient removal of ring artifacts and noise using machine‐learning approaches. The results open new possibilities for full‐field multi‐beam nanotomography and pave the way for future advancements in fast holotomography and artifact‐reduction techniques. [ABSTRACT FROM AUTHOR]

Resistive Random Access Memory (RRAM) is a prominent contender in the realm of emerging non-volatile memory technologies owing to its numerous advantages like simple structure, low power usage, high speed, and exceptional scalability. In the current study, RRAM device was fabricated using tantalum oxide (TaOx) as a resistive switching insulating oxide layer, which was sandwiched between two conducting electrodes, namely Ag and ITO. RF magnetron sputtering was used to deposit the insulating layer of TaOx at room temperature on the ITO substrate. Further, X-ray reflectivity and hard X-ray photoelectron spectroscopy analyses were conducted to find the thickness, roughness, and elemental composition of the deposited TaOx films. Using a semiconductor analyzer, the RRAM cell's first DC switching characteristics were determined. The data acquired exhibited a resistance ratio (RHRS/RLRS) of 120 showing a good distinction between the two-resistance states. Additionally, a thorough investigation was conducted to examine the electrical conduction mechanism occurring inside the fabricated RRAM device. [ABSTRACT FROM AUTHOR]

AI/ML-based data-driven methodologies are becoming increasingly effective in understanding and predicting plasma disruption in tokamaks by identifying critical signatures present in various diagnostic signals obtained from tokamaks. A high-performance ML-based disruption predictor requires large accurately labelled data. Until now, plasma shots from the ADITYA tokamak have primarily been classified (labelled) as disruptive or non-disruptive manually. Here, we present three computational techniques, namely the Sorted-array approach, the Interval comparison approach and the Threshold-Straight line method for automatic labelling of the ADITYA shots as disruptive or non-disruptive based on the plasma current dropdown time. Statistical analysis and comparison between automatic labelling and manual labelling indicate the promising potential of the proposed techniques. A correlation analysis is also conducted by incorporating plasma diagnostics such as Plasma current, Loop voltage, Bolometer, Mirnov, Hard X-ray, Soft–X-ray, Radiation from Hydrogen-alpha, ionised oxygen and ionised carbon. This comprehensive study offers valuable insights into diverse physical phenomena associated with disruptions. Furthermore, correlation analysis based on current quench time highlights the significance of different diagnostics in providing distinct signatures related to plasma disruption. The insights obtained from this work can play a pivotal role in advancing the development of data-driven disruption prediction systems for ADITYA tokamak. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the Al2O3/GaN critical buried interface of the next generation of gallium nitride (GaN)‐based transistors using time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) and hard X‐ray photoelectron spectroscopy (HAXPES). Results highlight that gallium oxidation at this interface is enhanced when increasing the Al2O3 thickness from 3 up to 20 nm. Gallium oxidation is reduced when using both O3 and H2O as oxidant precursors, compared with only H2O during the growth of Al2O3. In addition, the O3/H2O‐based Al2O3 favors a reduction of contaminants such as hydrogen and carbon but enhances the presence of halides (Cl− and F−) at this Al2O3/GaN interface. [ABSTRACT FROM AUTHOR]

We investigate the crosstalk between Transition-Edge Sensor (TES) pixels in a 24-pixel hard X-ray spectrometer array fabricated at the Advanced Photon Source, Argonne National Laboratory. Analysis shows thermal cross talk, possibly associated with insufficient thermalization, and rare but larger in magnitude electrical crosstalk between specific perpetrator-victim pixel combinations, potentially due to defects in the bias wiring or microwave multiplexing circuit. We use a method based on group-triggering and averaging to isolate the crosstalk response despite only having access to X-ray photon illumination uniform across the entire array. This allows us to identify thermal and electrical crosstalk between pixel pairs in repeated measurements to the level of 1 part in 1000 or better. In the array under study, the magnitude of observed crosstalk is small but comparable to the resolving power of this pixel design ( E / Δ E ∼ 1000 at 20 keV) and so potentially responsible for a degradation in energy resolution of the array at high incident photon rates. Having proven the methods to identify and quantify crosstalk in our setup, we can now consider mitigations. [ABSTRACT FROM AUTHOR]

The Biomedical Imaging and Therapy facility of the Canadian Light Source comprises two beamlines, which together cover a wide X-ray energy range from 13 keV up to 140 keV. The beamlines were designed with a focus on synchrotron applications in preclinical imaging and veterinary science as well as microbeam radiation therapy. While these remain a major part of the activities of both beamlines, a number of recent upgrades have enhanced the versatility and performance of the beamlines, particularly for high-resolution microtomography experiments. As a result, the user community has been quickly expanding to include researchers in advanced materials, batteries, fuel cells, agriculture, and environmental studies. This article summarizes the beam properties, describes the endstations together with the detector pool, and presents several application cases of the various X-ray imaging techniques available to users.

X-ray gas monitors (XGMs) are operated at the European XFEL for non-invasive single-shot pulse energy measurements and average beam-position monitoring. The underlying measurement principle is the photo-ionization of rare gas atoms at low gas pressures and the detection of the photo-ions and photo-electrons created. These are essential for tuning and sustaining self-amplified spontaneous emission (SASE) operation, machine radiation safety, and sorting single-shot experimental data according to pulse energy. In this paper, the first results from XGM operation at photon energies up to 30 keV are presented, which are far beyond the original specification of this device. Here, the Huge Aperture MultiPlier (HAMP) is used for single-shot pulse energy measurements since the standard X-ray gas monitor detectors (XGMDs) do not provide a sufficient signal-to-noise ratio, even at the highest operating gas pressures. A single-shot correlation coefficient of 0.98 is measured between consecutive XGMs operated with HAMP, which is as good as measuring with the standard XGMD detectors. An intra-train non-linearity of the HAMP signal is discovered, and operation parameters to mitigate this effect are studied. The upper repetition rate limit of HAMP operation at 2.25 MHz is also determined. Finally, the possibilities and limits for future XGM operation at photon energies up to 50 keV are discussed.

In the scope of the latest upgrade of the Swiss Light Source, five hard X-ray beamlines will be constructed or rebuilt. To use synergies between these beamline projects, a concept is developed here for hard X-ray beamlines that is tailored to the new storage ring. Herein, this concept is described from the source, via the front end, to the beamline optics. The latter will be outlined in detail, including a new and modular concept for hard X-ray monochromators, focusing optics and heat-load management. With a simple, easy-to-operate and robust beamline design, the new beamlines will greatly profit from the increased brilliance of the new storage ring. The performance increase is up to four orders of magnitude, while the beamline concept allows for the broad application of experimental techniques, from propagation-based methods, such as phase-contrast tomography, to imaging techniques with nanometre resolution. At the same time, spectroscopy experiments are possible as well as high-performance serial X-ray crystallography.

Ultrashort period 1.0 nm W/Si multilayers have potential as dispersive Bragg reflectors in high-resolution x-ray fluorescence. However, formation of WSix leads to poor optical performance. To address this, we introduce ultrathin 0.1 nm B4C diffusion barriers in sputter-deposited 1.0 nm W/Si, inhibiting W–Si interaction. We demonstrate that the peak reflectance at a wavelength of 0.834 nm increased with a factor of 3.4 compared to W/Si. Diffuse scattering measurements reveal no change in interfacial roughness when applying B4C barriers compared to W/Si. X-ray reflectivity analysis shows a substantial increase in optical contrast between Si and W as well as sharper transitions between the layers. Chemical analysis suggests that the B4C barrier reduces formation of WSix through partial substitution of W-silicide bonds with W-carbide/boride bonds, leading to an increase in optical contrast. The resulting structure of W/Si with B4C barriers offers a compelling alternative to the more established W/B4C multilayer at the ultrashort scale due to its superior soft- and hard x-ray reflectance. [ABSTRACT FROM AUTHOR]

In contrast to traditional X‐ray photoelectron spectroscopy (XPS), hard X‐ray photoelectron spectroscopy (HAXPES) can provide information from deeper within a sample while maintaining chemical resolution. However, working with higher energy X‐rays introduces a series of new or different issues ranging from energy calibration to factors associated with quantitative analysis. As part of the efforts to identify and increase community awareness about these issues, a workshop was held to review HAXPES metrology challenges with the perspective of converting it into a quantitative technique. A summary is hereby given of this workshop, which was entitled “What New Challenges Come with the Capabilities of HAXPES?” It was held in Portland, OR, USA, on November 7, 2023, and was primarily sponsored by the ASTM E42 Committee and the Applied Surface Science Division of the American Vacuum Society. This report contains summaries of the presentations and discussions at this workshop regarding the current open problems in HAXPES metrology. There were 20 participants at the workshop. [ABSTRACT FROM AUTHOR]

Hafnium Nitride (HfN) is a promising and very robust alternative to gold for applications of nanoscale metals. Details of the nanomorphology related to variations in strain states and optical properties can be crucial for applications in nanophotonics and plasmon‐assisted chemistry. Ultrafast reciprocal space mapping (URSM) with hard X‐rays is used to unveil the nanomorphology of thin HfN films. Static high‐resolution X‐ray diffraction reveals a twofold composition of the thin films being separated into regions with identical lattice constant and similar out‐of‐plane but hugely different in‐plane coherence lengths. URSM upon femtosecond laser excitation reveals different transient strain dynamics for the two respective Bragg peak components. This unambiguously locates the longer in‐plane coherence length in the first 15 nm of the thin film adjacent to the substrate. The transient shift of the broad diffraction peak displays the strain dynamics of the entire film, implying that the near‐substrate region hosts nanocrystallites with small and large coherence length, whereas the upper part of the film grows in small columnar grains. The results illustrate that URSM is a suitable technique for non‐destructive and depth‐resolved investigations of the morphology of nanostructures. [ABSTRACT FROM AUTHOR]

Optical quantum memories are key elements in modern quantum technologies to reliably store and retrieve quantum information. At present, they are conceptually limited to the optical wavelength regime. Recent advancements in x-ray quantum optics render an extension of optical quantum memory protocols to ultrashort wavelengths possible, thereby establishing quantum photonics at x-ray energies. Here, we introduce an x-ray quantum memory protocol that utilizes mechanically driven nuclear resonant 57Fe absorbers to form a comb structure in the nuclear absorption spectrum by using the Doppler effect. This room-temperature nuclear frequency comb enables us to control the waveform of x-ray photon wave packets to a high level of accuracy and fidelity using solely mechanical motions. This tunable, robust, and highly flexible system offers a versatile platform for a compact solid-state quantum memory at room temperature for hard x-rays. [ABSTRACT FROM AUTHOR]

Transition metal complexes, particularly copper hydrides, play an important role in various catalytic processes and molecular inorganic chemistry. This study employs synchrotron hard X‐ray spectroscopy to gain insights into the geometric and electronic properties of copper hydrides as potential catalysts for CO2 hydrogenation. The potential of high energy resolution X‐ray absorption near‐edge structure (HERFD‐XANES) and valence‐to‐core X‐ray emission (VtC‐XES) is demonstrated with measurement on Stryker's reagent (Cu6H6) and [Cu3(μ3‐H)(dpmppe)2](PF6)2 (Cu3H), alongside a non‐hydride copper compound ICu(dtbppOH) (Cuy−I). The XANES analysis reveals that coordination geometries strongly influence the spectra, providing only indirect details about hydride coordination. The VtC‐XES analysis exhibits a distinct signal around 8975 eV, offering a diagnostic tool to identify hydride ligands. Theoretical calculations support and extend these findings by comparing hydride‐containing complexes with their hydride‐free counterparts. [ABSTRACT FROM AUTHOR]

During thermonuclear bursts, it is suspected that cooling of the corona by the burst emission may be the cause of hard X-ray deficits. Although such a deficit has been observed in nine sources, it has not been observed from 4U 1608–52, a nearby prolific burster. Therefore, the authenticity and universality of the hard X-ray deficit may be in question. To investigate this suspicion, Insight–HXMT performed cadence observations during the low/hard state of 4U 1608–52 in 2022 September and detected 10 thermonuclear X-ray bursts. Two of these bursts show a double-peaked structure in the soft X-ray band, which could be caused by the high temperature of the burst emission and a marginal photospheric radius expansion (PRE) around the burst peak time. This is indicated by their peak fluxes being up to the Eddington limit and having a large colour factor at the peak of the bursts. A hard X-ray deficit is observed at a significant level during bursts at > 30 keV. Furthermore, the fraction of this deficit shows saturation at 50 per cent for the first eight bursts. This saturation may indicate that the corona is layered and only part of the corona is cooled by the bursts: for example, the part close to the neutron star surface is cooled while the rest remains intact during bursts. This result provides a clue to the geometry of the corona. For example, a possible scenario is that the corona has two forms: a quasi-spheric corona between the neutron star and the disc and a disc corona on both surfaces of the disc. [ABSTRACT FROM AUTHOR]

A fundamental goal of modern-day astrophysics is to understand the connection between supermassive black hole (SMBH) growth and galaxy evolution. Merging galaxies offer one of the most dramatic channels for galaxy evolution known, capable of driving inflows of gas into galactic nuclei, potentially fueling both star formation and central SMBH activity. Dual active galactic nuclei (dual AGNs) in late-stage mergers with nuclear pair separations <10 kpc are thus ideal candidates to study SMBH growth along the merger sequence since they coincide with the most transformative period for galaxies. However, dual AGNs can be extremely difficult to confirm and study. Hard X-ray (>10 keV) studies offer a relatively contamination-free tool for probing the dense obscuring environments predicted to surround the majority of dual AGN in late-stage mergers. To date, only a handful of the brightest and closest systems have been studied at these energies due to the demanding instrumental requirements involved. We demonstrate the unique capabilities of HEX-P to spatially resolve the soft and -- for the first time -- hard X-ray counterparts of closely-separated (~2" -- 5") dual AGNs in the local Universe. By incorporating physically-motivated obscuration models, we reproduce realistic broadband X-ray spectra expected for deeply embedded accreting SMBHs. Hard X-ray spatially resolved observations of dual AGNs -- accessible only to HEX-P -- wiU hence transform our understanding of dual AGN in the nearby Universe. [ABSTRACT FROM AUTHOR]

Depth-selective x-ray diffraction (XRD) technique was developed. In this technique, XRD spectra were measured using an energy dispersive (ED) x-ray detector at fixed angles. A straight capillary optic was used to define the incident x-ray beam, and a second straight capillary defined the beam path from the sample to detector. Thereby, only the XRD spectrum at the small intersection of two capillary optics could be obtained. A depth-selective XRD is possible by changing the sample position in depth. Many XRD peaks appear in a high-energy range more than 10 keV in the ED spectrum. The detection of these peaks will be advantageous for depth analysis because of low absorption in the sample. Depth-selective measurement would be advantageous over general XRD. In this study, depth-selective and ED-XRD spectra are demonstrated for the layered sample, which consisted of film-like Si powder and a muscovite film. [ABSTRACT FROM AUTHOR]

Many nanodevices and quantum devices, with their sizes often spanning from millimeters down to sub-nanometer, have intricate low-dimensional, non-uniform, or hierarchical structures on surfaces and interfaces. Since their functionalities are dependent on these structures, high-resolution surface-sensitive characterization becomes imperative to gain a comprehensive understanding of the function–structure relationship. We thus developed hard x-ray ptychographic reflectometry imaging, a new technique that merges the high-resolution two-dimensional imaging capabilities of hard x-ray ptychography for extended objects, with the high-resolution depth profiling capabilities of x-ray reflectivity for layered structures. The synergy of these two methods fully leverages both amplitude and phase information from ptychography reconstruction to not only reveal surface topography and localized structures, such as shapes and electron densities, but also yields statistical details, such as interfacial roughness that is not readily accessible through coherent imaging solely. The hard x-ray ptychographic reflectometry imaging is well-suited for three-dimensional imaging of mesoscopic samples, particularly those comprising planar or layered nanostructures on opaque supports, and could also offer a high-resolution surface metrology and defect analysis on semiconductor devices, such as integrated nanocircuits and lithographic photomasks for microchip fabrications. [ABSTRACT FROM AUTHOR]

Hard x-ray photoelectron spectroscopy (HAXPES) using monochromatic Cr Kα radiation (5414.8 eV) has been used to acquire XPS and Auger data on an argon gas cluster-sputtered CeO2 sample. Survey data, high-resolution scans of all observed photoelectron peaks, and high-resolution scans of Auger lines are presented herein. [ABSTRACT FROM AUTHOR]