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Showing papers on "Synchrotron radiation published in 2022"


Journal ArticleDOI
TL;DR: In this paper , a dual nitrogen source coordinated strategy was proposed to realize high dense Cu-N 4 SAS with a metal loading of 5.61 wt% supported on 3D N-doped carbon nanotubes/graphene structure.
Abstract: The emerging star of single atomic site (SAS) catalyst has been regarded as the most promising Pt-substituted electrocatalyst for oxygen reduction reaction (ORR) in anion-exchange membrane fuel cells (AEMFCs). However, the metal loading in SAS directly affects the whole device performance. Herein, we report a dual nitrogen source coordinated strategy to realize high dense Cu-N 4 SAS with a metal loading of 5.61 wt% supported on 3D N-doped carbon nanotubes/graphene structure wherein simultaneously performs superior ORR activity and stability in alkaline media. When applied in H 2 /O 2 AEMFC, it could reach an open-circuit voltage of 0.90 V and a peak power density of 324 mW cm -2 . Operando synchrotron radiation analyses identify the reconstruction from initial Cu-N 4 to Cu-N 4 /Cu-nanoclusters (NC) and the subsequent Cu-N 3 /Cu-NC under working conditions, which gradually regulate the d-band center of central metal and balance the Gibbs free energy of *OOH and *O intermediates, benefiting to ORR activity.

28 citations


Journal ArticleDOI
TL;DR: In this article , the authors summarized the achievements of multifarious synchrotron-radiation characterization methods in studying the local environments of single-atom catalysts (SACs).
Abstract: The unique structures of single-atom catalysts (SACs) endow them with widespread energy applications. This review summarized the achievements of multifarious synchrotron-radiation characterization methods in studying the local environments of SACs.

14 citations


Journal ArticleDOI
TL;DR: In this paper , the authors present the recently implemented "historical materials BAG", a community proposal giving to 10 European institutes the opportunity for guaranteed beamtime at two X-ray powder diffraction (XRPD) beamlines with a particular focus on applications to cultural heritage.
Abstract: The European Synchrotron Radiation Facility (ESRF) has recently commissioned the new Extremely Brilliant Source (EBS). The gain in brightness as well as the continuous development of beamline instruments boosts the beamline performances, in particular in terms of accelerated data acquisition. This has motivated the development of new access modes as an alternative to standard proposals for access to beamtime, in particular via the “block allocation group” (BAG) mode. Here, we present the recently implemented “historical materials BAG”: a community proposal giving to 10 European institutes the opportunity for guaranteed beamtime at two X-ray powder diffraction (XRPD) beamlines—ID13, for 2D high lateral resolution XRPD mapping, and ID22 for high angular resolution XRPD bulk analyses—with a particular focus on applications to cultural heritage. The capabilities offered by these instruments, the specific hardware and software developments to facilitate and speed-up data acquisition and data processing are detailed, and the first results from this new access are illustrated with recent applications to pigments, paintings, ceramics and wood.

11 citations


Journal ArticleDOI
TL;DR: In this article , the authors performed a statistical analysis using the first Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) catalog and identified a few discriminant properties between repeating and non-repeating FRBs such as the repetition rate, duration, bandwidth, spectral index, peak luminosity, and potential peak frequency.
Abstract: It is still a highly debated question as to whether fast radio bursts (FRBs) are classified into one or two populations. To probe this question, we perform a statistical analysis using the first Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) catalog and identify a few discriminant properties between repeating and non-repeating FRBs such as the repetition rate, duration, bandwidth, spectral index, peak luminosity, and potential peak frequency. If repeating and non-repeating FRBs belong to one population, their distribution distinctions for the repetition rate and duration can be explained by the selection effect due to the beamed emission as in Connor et al. However, we obtain that the distribution distinctions for the spectral index and potentially the peak frequency cannot be explained by the beamed emission within the framework of either the coherent curvature radiation or synchrotron maser emission. This indicates that there could be two populations. We further discuss three possible scenarios for the required two populations.

11 citations


Journal ArticleDOI
Jacco Vink, D.A. Prokhorov, Riccardo Ferrazzoli, Patrick Slane, Ping Zhu, Kazunori Asakura, Luca Baldini, Niccolò Bucciantini, Enrico Costa, A. Di Marco, Jeremy S. Heyl, Frédéric Baron, Tsunefumi Mizuno, Chi-Yung Ng, Melissa Pesce-Rollins, Brian D. Ramsey, John Rankin, Ajay Ratheesh, Carmelo Sgrò, Paolo Soffitta, Douglas A. Swartz, Toru Tamagawa, Martin C. Weisskopf, Yijia Yang, Ronaldo Bellazzini, R. Bonino, E. Cavazzuti, Luigi Costamante, N. Di Lalla, Luca Latronico, S. Maldera, Alberto Manfreda, Francesco Massaro, Ikuyuki Mitsuishi, Nicola Omodei, Chiara Oppedisano, Silvia Zane, Ivan Agudo, L. A. Antonelli, Matteo Bachetti, W. H. Baumgartner, F. Bianchi, Stephen D. Bongiorno, A. Brez, Fiamma Capitanio, S. Castellano, Stefano Ciprini, A. de Rosa, E. Del Monte, L. Di Gesu, I. Donnarumma, Victor Doroshenko, Michal Dovciak, S. Ehlert, Teruaki Enoto, Y. Evangelista, Sergio Fabiani, Javier A. García, Shuichi Gunji, Kiyoshi Hayashida, Wataru Iwakiri, Svetlana G. Jorstad, Vladimir Karas, Takao Kitaguchi, Jeffrey Kolodziejczak, Henric Krawczynski, Fabio La Monaca, Ioannis Liodakis, Andrea Marinucci, Alan P. Marscher, Herman L. Marshall, Giorgio Matt, Fabio Muleri, Stephen L. O'Dell, Alessandro Papitto, George G. Pavlov, A. L. Peirson, M. Perri, M. Pilia, A. Possenti, Juri Poutanen, Simonetta Puccetti, Roger W. Romani, Gloria Spandre, Fabrizio Tavecchio, Roberto Taverna, Yuzuru Tawara, Allyn F. Tennant, Nicolas Thomas, Francesco Tombesi, Alessio Trois, Sergey S. Tsygankov, Roberto Turolla, Kinwah Wu, Fei Xie 
TL;DR: In this paper , a pixel-by-pixel search for polarization provides a few tentative detections from discrete regions at the ∼ 3σ confidence level, but the significance is insufficient to claim a detection for individual pixels, but implies considerable turbulence on scales smaller than the angular resolution.
Abstract: We report on a ∼5σ detection of polarized 3–6 keV X-ray emission from the supernova remnant Cassiopeia A (Cas A) with the Imaging X-ray Polarimetry Explorer (IXPE). The overall polarization degree of 1.8% ± 0.3% is detected by summing over a large region, assuming circular symmetry for the polarization vectors. The measurements imply an average polarization degree for the synchrotron component of ∼2.5%, and close to 5% for the X-ray synchrotron-dominated forward shock region. These numbers are based on an assessment of the thermal and nonthermal radiation contributions, for which we used a detailed spatial-spectral model based on Chandra X-ray data. A pixel-by-pixel search for polarization provides a few tentative detections from discrete regions at the ∼ 3σ confidence level. Given the number of pixels, the significance is insufficient to claim a detection for individual pixels, but implies considerable turbulence on scales smaller than the angular resolution. Cas A’s X-ray continuum emission is dominated by synchrotron radiation from regions within ≲1017 cm of the forward and reverse shocks. We find that (i) the measured polarization angle corresponds to a radially oriented magnetic field, similar to what has been inferred from radio observations; (ii) the X-ray polarization degree is lower than in the radio band (∼5%). Since shock compression should impose a tangential magnetic-field structure, the IXPE results imply that magnetic fields are reoriented within ∼1017 cm of the shock. If the magnetic-field alignment is due to locally enhanced acceleration near quasi-parallel shocks, the preferred X-ray polarization angle suggests a size of 3 × 1016 cm for cells with radial magnetic fields.

9 citations


Journal ArticleDOI
TL;DR: In this article , the authors demonstrate the possibility of retrieving a high-quality image of the crystalline sample, with unprecedented quality, using the first 4th-generation synchrotron source.
Abstract: New 4th-generation synchrotron sources, with their increased brilliance, promise to greatly improve the performances of coherent X-ray microscopy. This perspective is of major interest for crystal microscopy, which aims at revealing the 3D crystalline structure of matter at the nanoscale, an approach strongly limited by the available coherent flux. Our results, based on Bragg ptychography experiments performed at the first 4th-generation synchrotron source, demonstrate the possibility of retrieving a high-quality image of the crystalline sample, with unprecedented quality. Importantly, the larger available coherent flux produces datasets with enough information to overcome experimental limitations, such as strongly deteriorated scanning conditions. We show this achievement would not be possible with 3rd-generation sources, a limit that has inhibited the development of this otherwise powerful microscopy method, so far. Hence, the advent of next-generation synchrotron sources not only makes Bragg ptychography suitable for high throughput studies but also strongly relaxes the associated experimental constraints, making it compatible with a wider range of experimental set-ups at the new synchrotrons.

9 citations


Journal ArticleDOI
TL;DR: In this article , a non-nucleophilic phenolate-based magnesium complex (PMC) electrolyte enabling reversible stripping/plating with a low over-potential of 84.3 mV at 1 mA cm-2.
Abstract: Rechargeable magnesium batteries (RMBs) are one of the more promising future energy storage systems. This work proposes a non‐nucleophilic phenolate‐based magnesium complex (PMC) electrolyte enabling reversible Mg stripping/plating with a low over‐potential of 84.3 mV at 1 mA cm–2. Subsequently, Co doping is introduced to prepare FeS2, Fe0.9Co0.1S2, Fe0.75Co0.25S2 and Fe0.5Co0.5S2. Multiple characterizations confirm that Co doping can expand the crystal lattice and reduce particle sizes, thus benefiting cathode reactions. With Co doping, Fe orbitals can be expected to transform from high spin to low spin states without valence changes while the spin state of Co atoms is little influenced. Then, Co‐doped FeS2 cathodes coated on copper collectors coupling with a PMC electrolyte for RMBs show superior electrochemical performance among reported chalcogenide cathodes, displaying a maximum discharge capacity (700 mAh g–1) at 0.1 A g–1. Specifically, Fe0.5Co0.5S2 cathodes exhibit the best cycling stability and shortest activation time. Even at 1 A g–1, a discharge capacity (164 mAh g–1) is still achieved after 1000 cycles. Mechanistic studies indicate that copper collector participates in the cathode reactions accompanied by Cu1.8S generation while Fe and Co species play a synergistic catalytic role, providing effective tactics for rational design of electrolytes, conversion type cathodes, and collectors.

9 citations


Journal ArticleDOI
TL;DR: In this article , a superconducting magnet for a compact heavy-ion synchrotron in collaboration with the National Institutes for Quantum Science and Technology (QST) is described, and a short model with the same cross section as the designed coil was fabricated and an excitation test was carried out.
Abstract: A project to develop a next-generation small facility for heavy-ion radiotherapy called Quantum Scalpel is underway at the National Institutes for Quantum Science and Technology (QST), having started in 2016. One of the aims of this project is to downsize the synchrotron by applying superconducting technology. With a view to accomplishing this, we have been developing a superconducting magnet for a compact heavy-ion synchrotron in collaboration with QST. This superconducting magnet can generate a dipole field of 3.5 T at an operating current of 265 A. It adopts conduction cooling with GM cryocoolers and is designed to be able to raise the magnetic field from 0.3 T to 3.5 T in 5 seconds. Such high-speed excitation causes large AC loss in the superconducting coil. In this paper, the thermal design result, including countermeasures for this AC loss, is described. In addition, a short model with the same cross section as the designed coil was fabricated and an excitation test was carried out. As a result of the test, it was confirmed that the magnet can generate the designed maximum field of 3.5 T in 5 seconds without quench. And it was also confirmed that there was a difference of about 0.5 K between the measurement results and the thermal calculation results of the pattern test. The design of a full-scale magnet is almost completed, and the results of the present work shows that the conduction-cooling method using 4K GM cryocoolers is applicable to the superconducting magnet for the synchrotron.

8 citations


Journal ArticleDOI
TL;DR: In this article, the authors investigated whether the γ-rays can be produced by the high-energy electrons/positrons in a nebula powered by PSR J2229+6114.

8 citations


Journal ArticleDOI
TL;DR: In this paper, a comprehensive multi-material and multi-method approach based on the combination of synchrotron radiation X-ray micro-analytical techniques (i.e., Xray diffraction, Xray fluorescence and Xray absorption near edge structure spectroscopy at S K/Ag L3-/As K-edges) and vibrational micro-spectroscopy methods was proposed to unveil the causes and mechanism of darkening of “fake-gilded” decorations in tempera paintings, originally consisting of an unusual mixture of As2
Abstract: Redox processes activated by environmental factors have been identified as the main cause of the chromatic alterations of a number of artists’ pigments, including the yellow pigment orpiment (As2S3). Although a general comprehension of the mechanisms has been provided through characterization of degradation compounds of As2S3, experimental evidences to prove how other paint components and how different environmental agents influence the formation pathways of specific secondary compounds are still lacking. Thus, it becomes fundamental to develop a methodological strategy which enable achieving a discrimination among the causes affecting the chemical stability of more heterogenous As2S3-based paints and defining the mechanism through which the alteration establishes and evolves, with the ultimate goal of optimizing the preventive conservation measures of unique masterpieces. In this paper, we propose a comprehensive multi-material and multi-method approach based on the combination of synchrotron radiation X-ray micro-analytical techniques (i.e., X-ray diffraction, X-ray fluorescence and X-ray absorption near edge structure spectroscopy at S K-/Ag L3-/As K-edges) and vibrational micro-spectroscopy methods to unveil the causes and mechanism of darkening of “fake-gilded” decorations in tempera paintings, originally consisting of an unusual mixture of As2S3 and metallic silver (Ag0). Such degradation process is a not yet understood phenomenon threatening a series of Old Master paintings, including those by the Italian painters Cimabue and Pietro Lorenzetti. The high specificity, sensitivity and lateral resolution of the employed analytical methods allowed providing first-time evidence for the presence of black acanthite (α-Ag2S), mimetite [Pb5(AsO4)3Cl] and syngenite [K2Ca(SO4)2∙H2O] as degradation products of the “fake-gilded” decorations in the Maesta by Cimabue (Church of Santa Maria dei Servi, Bologna, Italy). Furthermore, the study of the painting combined with that of tempera paint mock-ups permitted to explore and define the environmental agents and internal factors causing the darkening, by proving that: (i)Ag0 and moisture are key-factors for triggering the transformation of As2S3 to α-Ag2S and As-oxides; (ii)S2--ions arising from the degradation of As2S3 are the main responsible for the formation of α-Ag2S; (iii)light exposure strengthens the tendency of the paint components towards alteration. Based on our findings, we finally propose a degradation mechanism of As2S3/Ag0-based tempera paints.

8 citations


Journal ArticleDOI
TL;DR: In this paper , Mössbauer spectroscopy and X-ray diffraction were used to determine the precision values of the hyperfine interaction parameters and the crystal structure of FeBO3 single crystals in a wide temperature range.

Journal ArticleDOI
01 Jan 2022
TL;DR: In this paper , the key factors that should be considered during the planning and execution of a time-resolved structural study are outlined, with a particular focus on synchrotron-based experiments.
Abstract: With recent developments in X-ray sources, instrumentation and data-analysis tools, time-resolved crystallographic experiments, which were originally the preserve of a few expert groups, are becoming simpler and can be carried out at more radiation sources, and are thus increasingly accessible to a growing user base. However, these experiments are just that: discrete experiments, not just `data collections'. As such, careful planning and consideration of potential pitfalls is required to enable a successful experiment. Here, some of the key factors that should be considered during the planning and execution of a time-resolved structural study are outlined, with a particular focus on synchrotron-based experiments.

Journal ArticleDOI
TL;DR: In this article , Synchrotron radiation X-ray microanalytical techniques and vibrational micro-spectroscopy methods were used to establish the factors and mechanism of darkening of “fake-gilded” decorations in the Maestà by Cimabue and aged paint mock-ups.
Abstract: Synchrotron radiation X-ray micro-analytical techniques and vibrational micro-spectroscopy methods were used to establish the factors and mechanism of darkening of “fake-gilded” decorations in the Maestà by Cimabue and aged paint mock-ups.

Journal ArticleDOI
TL;DR: In this article , a review of the research and development of SCUs worldwide from the late 1970s to 2021 is presented, and the SCU design requirements and compares the theory limits of different types of planar and helical SCUs.
Abstract: Superconducting undulators (SCUs) with a period >15 mm can offer a much higher on-axis undulator field B 0 than state-of-the-art cryogenic permanent magnet undulators with the same period and vacuum gap. The commissioned NbTi planar SCUs for user operation in the Karlsruhe Institute of Technology synchrotron and the advanced photon source storage ring are operated stably without quenches, producing outperformed photon flux in the high energy part of the hard x-ray spectrum. Another potential advantage of deploying SCU is its radiation hardness, a crucial characteristic for being used in free electron lasers (FELs) driven by high repetition rate superconducting linear accelerators (LINACs) and diffraction limited storage rings (DLSRs) with small vacuum gap and large averaged beam current. The development of shorter period but high field SCU is an important mission in an EU founded CompactLight project as this technology would reduce both the length of undulators and the length of LINACs. This review paper first overviews the research and development of SCUs worldwide from the late 1970s to 2021, then presents the SCU design requirements and compares the theory limits of different types of planar and helical SCUs, and finally reviews the technical challenges including the SCU cryostat, the magnetic field measurement, the integral/local field correction and the high-temperature superconductor (HTS) challenges and prospects the research needs for SCUs.

Journal ArticleDOI
TL;DR: In this paper , the authors demonstrate the possibility of retrieving a high-quality image of the crystalline sample, with unprecedented quality, using the first 4th-generation synchrotron source.
Abstract: New 4th-generation synchrotron sources, with their increased brilliance, promise to greatly improve the performances of coherent X-ray microscopy. This perspective is of major interest for crystal microscopy, which aims at revealing the 3D crystalline structure of matter at the nanoscale, an approach strongly limited by the available coherent flux. Our results, based on Bragg ptychography experiments performed at the first 4th-generation synchrotron source, demonstrate the possibility of retrieving a high-quality image of the crystalline sample, with unprecedented quality. Importantly, the larger available coherent flux produces datasets with enough information to overcome experimental limitations, such as strongly deteriorated scanning conditions. We show this achievement would not be possible with 3rd-generation sources, a limit that has inhibited the development of this otherwise powerful microscopy method, so far. Hence, the advent of next-generation synchrotron sources not only makes Bragg ptychography suitable for high throughput studies but also strongly relaxes the associated experimental constraints, making it compatible with a wider range of experimental set-ups at the new synchrotrons.

Journal ArticleDOI
TL;DR: In this paper , radio synchrotron emission was detected in the galaxy cluster Abell 2255, and it was shown that the magnetic field energy density was at least 100 times higher than expected from a simple compression of primordial fields, presumably implying that dynamo operates efficiently also in the cluster periphery.
Abstract: The hot plasma within merging galaxy clusters is predicted to be filled with shocks and turbulence that may convert part of their kinetic energy into relativistic electrons and magnetic fields generating synchrotron radiation. Analyzing Low Frequency Array (LOFAR) observations of the galaxy cluster Abell 2255, we show evidence of radio synchrotron emission distributed over very large scales of at least 5 megaparsec. The pervasive radio emission witnesses that shocks and turbulence efficiently transfer kinetic energy into relativistic particles and magnetic fields in a region that extends up to the cluster outskirts. The strength of the emission requires a magnetic field energy density at least 100 times higher than expected from a simple compression of primordial fields, presumably implying that dynamo operates efficiently also in the cluster periphery. It also suggests that nonthermal components may contribute substantially to the pressure of the intracluster medium in the cluster periphery.

Journal ArticleDOI
TL;DR: In this paper , the chiroptical properties of thin-film samples of two dithiophene-based oligothiophenes with optoelectronic properties were carried out at Diamond B23 beamline using the synchrotron radiation electronic circular dichroism imaging (SR‐ECDi) facility.
Abstract: The study of the chiroptical properties of thin‐film samples of two chiral benzo[1,2‐b:4,5‐b’]dithiophene‐based oligothiophenes with optoelectronic properties was carried out at Diamond B23 beamline using the synchrotron radiation electronic circular dichroism imaging (SR‐ECDi) facility. The experimental results support the hypothesis that the non‐reciprocal circularly polarized absorption observed in these materials is due to the combined linear dichroism and linear birefringence contributions. The mapping at 50‐µM spatial resolution revealed that several species coexist in the mesoscopic chiral domains likely due to different aggregated phases, which were identified in the films by SR‐ECDi but could not be detected with benchtop ECD instruments.

Journal ArticleDOI
TL;DR: In this paper , synchrotron X-ray refraction radiography (SXRR) has been paired with in-situ heat treatment to monitor microstructure and porosity evolution as a function of temperature.
Abstract: For the first time, synchrotron X-ray refraction radiography (SXRR) has been paired with in-situ heat treatment to monitor microstructure and porosity evolution as a function of temperature. The investigated material was a laser powder bed fusion (LPBF) manufactured AlSi10Mg, where the initial eutectic Si network is known to disintegrate and spherodize into larger particles with increasing temperature. Such alloy is also prone to thermally induced porosity (TIP). We show that SXRR allows detecting the changes in the Si-phase morphology upon heating, while this is currently possible only using scanning electron microscopy. SXRR also allows observing the growth of pores, usually studied via X-ray computed tomography, but on much smaller fields-of-view. Our results show the great potential of in-situ SXRR as a tool to gain in-depth knowledge of the susceptibility of any material to thermally induced damage and/or microstructure evolution over statistically relevant volumes.

Journal ArticleDOI
TL;DR: In this paper , microscopic damages such as fiber/matrix debonding and micro-cracks under mixed-mode (mode I + II) loading are characterized in situ using nondestructive nanoscopic synchrotron radiation X-ray computed tomography (nanoscopic SR X-CT).
Abstract: Nanoscale fracture mechanism in CFRPs is still debated owing to the considerable difficulty in determining the three-dimensional mechanism of fracture using conventional techniques such as optical and/or electron microscopy relying on side-surface- and fracture-surface-based observation. In this study, microscopic damages such as fiber/matrix debonding and microcracks under mixed-mode (mode I + II) loading are characterized in situ using nondestructive nanoscopic synchrotron radiation X-ray computed tomography (nanoscopic SR X-CT). It is clearly shown that crack formation proceeds in three steps: (i) initiation at the carbon fiber/epoxy matrix interface, (ii) propagation into the epoxy, and (iii) formation of microcracks (hackles) in the resin matrix, and the resulting microstructures of cracks at the nanoscale are largely affected by the local fiber geometrical distributions. A sharp and straight interfacial crack initiates at the “thin” epoxy-resin region (thickness < half the diameter of the carbon fiber (dCF)) and propagates along the carbon fiber/epoxy interface. The sharp cracks propagate into the epoxy at the “thick” epoxy-region (thickness > ∼1/2 dCF) and hackles are formed in the resin matrix perpendicular to the local principal tensile stress direction. Nanoscopic SR X-CT provides information on three-dimensional mechanisms at the nanoscale during deformation, which is indispensable for understanding heterogenous materials such as CFRPs.

Journal ArticleDOI
TL;DR: In this paper , the authors revisited predictions of the maximum energy to which electrons can be accelerated at a relativistic blast wave, and showed that simultaneous fits to the X-ray and TeV gamma-ray emission of this object are not possible unless the limit on acceleration imposed by the ambient magnetic field is comparable to or weaker than that imposed by radiation losses.
Abstract: Abstract Motivated by the detection of very-high-energy (VHE) gamma rays deep in the afterglow emission of a gamma-ray burst (GRB), we revisit predictions of the maximum energy to which electrons can be accelerated at a relativistic blast wave. Acceleration at the weakly magnetized forward shock of a blast wave can be limited by either the rapid damping of turbulence generated behind the shock, the effect of a large-scale ambient magnetic field, or radiation losses. Within the confines of a standard, single-zone, synchrotron self-Compton (SSC) model, we show that observations of GRB 190829A rule out a rapid damping of the downstream turbulence. Furthermore, simultaneous fits to the X-ray and TeV gamma-ray emission of this object are not possible unless the limit on acceleration imposed by the ambient magnetic field is comparable to or weaker than that imposed by radiation losses. This requires the dominant length scale of the turbulence behind the shock to be larger than that implied by particle-in-cell simulations. However, even then, Klein–Nishina effects prevent production of the hard VHE gamma-ray spectrum suggested by observations. Thus, TeV observations of GRB afterglows, though still very sparse, are already in tension with the SSC emission scenario.

Journal ArticleDOI
17 Feb 2022-Analyst
TL;DR: In this article , the authors used synchrotron-sourced attenuated total reflection Fourier transform infrared (ATR-FTIR) microspectroscopy to provide spatio-temporal resolution of chemical changes within fingermark droplets, as a function of time since deposition.
Abstract: Degradation of fingermark residue has a major impact on the successful forensic detection of latent fingermarks. The time course of degradation has been previously explored with bulk chemical analyses, but little is known about chemical alterations within specific regions of the fingermark, which is difficult to study with bulk measurement. Here we report the use of synchrotron-sourced attenuated total reflection-Fourier transform infrared (ATR-FTIR) microspectroscopy to provide spatio-temporal resolution of chemical changes within fingermark droplets, as a function of time since deposition, under ambient temperature conditions. Eccrine and sebaceous material within natural fingermark droplets were imaged on the micron scales at hourly intervals from the time of deposition until the first 7-13 hours after deposition, revealing that substantial dehydration occurred within the first 8 hours. Changes to lipid material were more varied, with samples exhibiting an increase or decrease in lipid concentration due to the degradation and redistribution of this material. Across 12 donors, it was noticeable that the initial chemical composition and morphology of the droplet varied greatly, which appeared to influence the rate of change of the droplet over time. Further, this study attempted to quantify the total water content within fingermark samples. The wide-spread nature and strength of the absorption of Terahertz/Far-infrared (THz/Far-IR) radiation by water vapour molecules were exploited for this purpose, using THz/Far-IR gas-phase spectroscopy. Upon heating, water confined in natural fingermarks was evaporated and expanded in a vacuum chamber equipped with multipass optics. The amount of water vapour was then quantified by high-spectral resolution analysis, and fingermarks were observed to lose approximately 14-20 μg of water. The combination of both ATR-FTIR and Far-IR gas-phase techniques highlight important implications for experimental design in fingermark research, and operational practices used by law enforcement agencies.

Proceedings ArticleDOI
02 Mar 2022
TL;DR: SISSI-Bio is the Chemical and Life Sciences branch of the SISSI (Synchrotron Infrared Source for Spectroscopy and Imaging) at Elettra-Sincrotrone, Trieste, Italy as discussed by the authors .
Abstract: SISSI-Bio is the Chemical and Life Sciences branch of the infrared beamline SISSI (Synchrotron Infrared Source for Spectroscopy and Imaging) at Elettra-Sincrotrone, Trieste, Italy. The laboratory has always been kept up-to-date with the latest equipment for Fourier Transform InfraRed (FTIR) analysis and currently hosts three endstations: one for spectroscopy, one for microscopy and one for nanospectroscopy. Although the synchrotron radiation allows for measurements at the diffraction limit over the full IR spectral range, all three end stations can alternatively be operated with benchtop sources, increasing the usage time of the setups beyond the infrared synchrotron radiation availability. In this contribution, the SISSI-Bio equipment will be presented in an integrated manner to highlight the multipurpose capabilities of the laboratory, emphasizing the opportunities for facility users and collaborators to perform cutting-edge scientific experiments. Selected examples, focusing on multi-scale and correlative analyses will be presented, highlighting topics such as cell and tissue analysis for FTIR hyperspectral histology and cytology, strategies for bio-specimen measurements in physiological conditions, environmental science and cultural heritage. The short-term development plans to incur in the field of biophysics in the far-IR and THz region will be also introduced.

Journal ArticleDOI
01 Sep 2022
TL;DR: XANES spectroscopy as mentioned in this paper offers substantial information about the local structure of biological samples, encompassing those without long range order such as Pt anticancer molecules, and nanometre scale or amorphous particles of calcium phosphate.
Abstract: XANES spectroscopy, which uses synchrotron radiation as a probe, offers substantial information about the local structure of biological samples, encompassing those without long range order such as Pt anticancer molecules, and nanometre scale or amorphous particles of calcium phosphate. Its subcellular spatial resolution, as well as its capacity to operate at room temperatures and pressures represent major advantages for medical research. Moreover, paraffin embedded biopsy samples can be analysed without any further preparation, Key publications which illustrate these capacities are presented.

Journal ArticleDOI
TL;DR: In this article , a memory and CPU efficient coherent mode decomposition (CMD) method for wave-optics based simulation of the partially coherent undulator radiation propagation through a hard X-ray beamline in a 3rd generation synchrotron radiation source is presented.
Abstract: Application examples of a memory and CPU efficient coherent mode decomposition (CMD) method for wave-optics based simulation of the partially coherent undulator radiation propagation through a hard X-ray beamline in a 3rd generation synchrotron radiation source are presented. The high efficiency of the method is achieved thanks to the analytical treatment of the common quadratic phase terms that are developed in the phase of cross-spectral density (CSD) of partially coherent radiation at a distance from source. This treatment allows for a considerable, several orders of magnitude, reduction of the 4D CSD mesh density (and the memory occupied by the CSD) required for ensuring sufficient accuracies of wavefront propagation simulations with the modes produced by the CMD at a beamline entrance. This method, implemented in the "Synchrotron Radiation Workshop" open-source software, dramatically increases the feasibility of the CMD of 4D CSD for producing 2D coherent modes for a large variety of applications at storage rings and other types of radiation sources.


Journal ArticleDOI
TL;DR: In this article , the krypton number densities in a sooting, atmospheric pressure, non-premixed coflow flame that is widely used in combustion research were measured using synchrotron x-ray fluorescence.
Abstract: Synchrotron x-ray fluorescence has been used to measure temperatures in optically dense gases where traditional methods would fail. These data provide a benchmark for stringent tests of computational fluid dynamics models for complex systems where physical and chemical processes are intimately linked. The experiments measured krypton number densities in a sooting, atmospheric pressure, nonpremixed coflow flame that is widely used in combustion research. The experiments not only form targets for the models, but the simulations also identify potential sources of uncertainties in the measurements, allowing for future improvements.

Journal ArticleDOI
TL;DR: In this paper , the introduction of synchrotron radiation X-ray techniques and their applications in single-atom catalysts (SACs) are discussed, as well as a systematic summary of the applications of Synchronized Radiation X-Ray (SRX) on different types of SACs (noble metals and transition metals).
Abstract: Single atom catalysts (SACs) can achieve a maximum atom utilization efficiency of 100%, which provides significantly increased active sites compared with traditional catalysts during catalytic reactions. Synchrotron radiation technology is an important characterization method for identifying single‐atom catalysts. Several types of internal information, such as the coordination number, bond length and electronic structure of metals, can all be analyzed. This review will focus on the introduction of synchrotron radiation techniques and their applications in SACs. First, the fundamentals of synchrotron radiation and the corresponding techniques applied in characterization of SACs will be briefly introduced, such as X‐ray absorption near edge spectroscopy and extended X‐ray absorption fine structure spectroscopy and in situ techniques. The detailed information obtained from synchrotron radiation X‐ray characterization is described through four routes: 1) the local environment of a specific atom; 2) the oxidation state of SACs; 3) electronic structures at different orbitals; and 4) the in situ structure modification during catalytic reaction. In addition, a systematic summary of synchrotron radiation X‐ray characterization on different types of SACs (noble metals and transition metals) will be discussed.

Journal ArticleDOI
TL;DR: In this paper , a new ellipsometry method for soft X-ray SHG was proposed to suppress the contribution of second-harmonic radiation from the light source through measurements of a GaAs(100) crystal.
Abstract: Second harmonic generation (SHG) is a unique non-linear optical effect that can be used to investigate chemical states of molecules at surfac-es/interfaces. By the use of soft X-rays, SHG gains element selectivity through the inner-core excitation resonance. However, it is challenging to observe SHG signals separately from the second-order light generated from the undulator. Here, we report a new ellipsometry method for soft X-ray SHG to suppress the contribution of second-harmonic radiation from the light source. Through measurements of a GaAs(100) crystal, we demonstrate that pure SHG signals can be obtained for the horizontally polarized component. The present method is generally applicable regard-less of the incident photon energy and hence the absorption edge of the targeted materials. If combined with optical filters blocking the sec-ond-harmonic radiation and equipped with soft X-ray phase shifters, the method allows one to obtain further information from SHG signals such as tensor components of second-order non-linear susceptibility.

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TL;DR: In this article , a site selective synthesis of a homogeneous WOC with two adjacent 3D metals, [Co2Ni2(PW9O34)2]10- (CoNi2P2) as a tractable molecular model for CoNi oxide, with the use of multi-wavelength synchrotron X-radiation anomalous dispersion scattering (synchoretron XRAS) that quantifies both the location and percent occupancy of Co (∼97% outer-central-belt positions only) and Ni ( ∼97% inner-central belt positions only).
Abstract: Mixed 3d metal oxides are some of the most promising water oxidation catalysts (WOCs), but it is very difficult to know the locations and percent occupancies of different 3d metals in these heterogeneous catalysts. Without such information, it is hard to quantify catalysis, stability, and other properties of the WOC as a function of the catalyst active site structure. This study combines the site selective synthesis of a homogeneous WOC with two adjacent 3d metals, [Co2Ni2(PW9O34)2]10- (Co2Ni2P2) as a tractable molecular model for CoNi oxide, with the use of multiwavelength synchrotron X-radiation anomalous dispersion scattering (synchrotron XRAS) that quantifies both the location and percent occupancy of Co (∼97% outer-central-belt positions only) and Ni (∼97% inner-central-belt positions only) in Co2Ni2P2. This mixed-3d-metal complex catalyzes water oxidation an order of magnitude faster than its isostructural analogue, [Co4(PW9O34)2]10- (Co4P2). Four independent and complementary lines of evidence confirm that Co2Ni2P2 and Co4P2 are the principal WOCs and that Co2+(aq) is not. Density functional theory (DFT) studies revealed that Co4P2 and Co2Ni2P2 have similar frontier orbitals, while stopped-flow kinetic studies and DFT calculations indicate that water oxidation by both complexes follows analogous multistep mechanisms, including likely Co-OOH formation, with the energetics of most steps being lower for Co2Ni2P2 than for Co4P2. Synchrotron XRAS should be generally applicable to active-site-structure-reactivity studies of multi-metal heterogeneous and homogeneous catalysts.

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TL;DR: In this article , the authors employ combined particle-in-cell and polarized radiation transfer simulations to study multi-wavelength radiation and optical polarization signatures under the leptonic scenario from relativistic magnetic reconnection.
Abstract: It is commonly believed that blazar jets are relativistic magnetized plasma outflows from supermassive black holes. One key question is how the jets dissipate magnetic energy to accelerate particles and drive powerful multi-wavelength flares. Relativistic magnetic reconnection has been proposed as the primary plasma physical process in the blazar emission region. Recent numerical simulations have shown strong acceleration of nonthermal particles that may lead to multi-wavelength flares. Nevertheless, previous works have not directly evaluated $\gamma$-ray signatures from first-principle simulations. In this paper, we employ combined particle-in-cell and polarized radiation transfer simulations to study multi-wavelength radiation and optical polarization signatures under the leptonic scenario from relativistic magnetic reconnection. We find harder-when-brighter trends in optical and {\it Fermi-LAT} $\gamma$-ray bands as well as closely correlated optical and $\gamma$-ray flares. The optical polarization angle swings are also accompanied by $\gamma$-ray flares with trivial time delays. Intriguingly, we find highly variable synchrotron self Compton signatures due to inhomogeneous particle distributions during plasmoid mergers. This feature may result in fast $\gamma$-ray flares or orphan $\gamma$-ray flares under the leptonic scenario, complementary to the frequently considered mini-jet scenario. It may also infer neutrino emission with low secondary synchrotron flux under the hadronic scenario, if plasmoid mergers can accelerate protons to very high energy.