Synchrotron Radiation Research Articles

In situ cell for grazing-incidence x-ray diffraction on thin films in thermal catalysis.

A cell for synchrotron-based grazing-incidence x-ray diffraction at ambient pressures and moderate temperatures in a controlled gas atmosphere is presented. The cell is suited for the in situ study of thin film samples under catalytically relevant conditions. To some extent, in addition to diffraction, the cell can be simultaneously applied for x-ray reflectometry and fluorescence studies. Different domes enclosing the sample have been studied and selected to ensure minimum contribution to the diffraction patterns. The applicability of the cell is demonstrated using synchrotron radiation by monitoring structural changes of a 3nm Pd thin film upon interaction with gas-phase hydrogen and during acetylene semihydrogenation at 150 °C. The cell allows investigation of very thin films under catalytically relevant conditions.

The ALMA View of Positive Black Hole Feedback in the Dwarf Galaxy Henize 2–10

Henize 2–10 is a dwarf starburst galaxy hosting a ∼106 M ⊙ black hole (BH) that is driving an ionized outflow and triggering star formation within the central ∼100 pc of the galaxy. Here, we present Atacama Large Millimeter/submillimeter Array continuum observations from 99 to 340 GHz, as well as spectral line observations of the molecules CO (1–0, 3–2), HCN (1–0, 3–2), and HCO+ (1–0, 3–2), with a focus on the BH and its vicinity. Incorporating centimeter-wave radio measurements from the literature, we show that the spectral energy distribution of the BH is dominated by synchrotron emission from 1.4 to 340 GHz, with a spectral index of α ≈ − 0.5. We analyze the spectral line data and identify an elongated molecular gas structure around the BH with a velocity distinct from the surrounding regions. The physical extent of this molecular gas structure is ≈130 pc × 30 pc and the molecular gas mass is ∼106 M ⊙. Despite an abundance of molecular gas in this general region, the position of the BH is significantly offset from the peak intensity, which may explain why the BH is radiating at a very low Eddington ratio. Our analysis of the spatially resolved line ratio between CO J = 3–2 and J = 1–0 implies that the CO gas in the vicinity of the BH is highly excited, particularly at the interface between the BH outflow and the regions of triggered star formation. This suggests that the cold molecular gas is being shocked by the bipolar outflow from the BH, supporting the case for positive BH feedback.

Develop an automated data acquisition system for TPS correction magnet power supply

Taiwan Photon Source is a third-generation 3 GeV synchrotron light source. Since the successful operation of the first beamline in 2013, comprehensive long-term testing and acceptance work has been carried out to ensure the stable operation of various types of correction magnet power supplies, totalling 1038 units. To standardise and save workforce and time for the measurement of correction magnet power supplies, an automated data acquisition system platform for correction magnet power supplies was developed using LabVIEW. This platform integrates control interface cards, high-resolution digital voltmeters, and analysis instruments. It also includes linearization and calibration compensation for the multi-channel direct constant current transformer to ensure simultaneous measurement of 24 magnet power supplies. Furthermore, it can automatically generate test reports in Word format, saving significant human resources and time. This platform has verified TPS correction magnet power supplies before installation, reducing the failure rate. Regarding measurement results, the output current ripple for the DCCT version is within five ppm, while the shunt resistor version is within ten ppm. The long-term current stability is consistently within ten ppm. The development of the fully automated data acquisition system platform and the measurement of 1038 power supplies were completed in four months.

CLASS Angular Power Spectra and Map-component Analysis for 40 GHz Observations through 2022

Measurement of the largest angular scale (ℓ < 30) features of the cosmic microwave background (CMB) polarization is a powerful way to constrain the optical depth to reionization and search for the signature of inflation through the detection of primordial B-modes. We present an analysis of maps covering 73.6% of the sky made from the 40 GHz channel of the Cosmology Large Angular Scale Surveyor (CLASS) from 2016 August to 2022 May. Taking advantage of the measurement stability enabled by front-end polarization modulation and excellent conditions from the Atacama Desert, we show this channel achieves higher sensitivity than the analogous frequencies from satellite measurements in the range 10 < ℓ < 100. Simulations show the CLASS linear (circular) polarization maps have a white noise level of 125(130)μKarcmin . We measure the Galaxy-masked EE and BB spectra of diffuse synchrotron radiation and compare to space-based measurements at similar frequencies. In combination with external data, we expand measurements of the spatial variations of the synchrotron spectral energy density (SED) to include new sky regions and measure the diffuse SED in the harmonic domain. We place a new upper limit on a background of circular polarization in the range 5 < ℓ < 125 with the first bin showing D ℓ < 0.023 μKCMB2 at 95% confidence. These results establish a new standard for recovery of the largest-scale CMB polarization from the ground and signal exciting possibilities when the higher sensitivity and higher-frequency CLASS channels are included in the analysis.

Statistical characterization of the collective synchrotron radiation power emitted by non-ideal magnetized plasma fluids in relativistic jets

The problem of determining the collective synchrotron radiation power emitted by non-ideal magnetized plasma fluids at kinetic equilibrium in relativistic jets is addressed. A covariant statistical kinetic approach is implemented based on a novel solution for the corresponding non-isotropic kinetic distribution function (KDF). This is expressed by a Gaussian-like solution that is consistent with relativistic magnetic moment conservation holding in collisionless magnetized plasmas and predicts tensorial equation of state and pressure anisotropy which are specific for these systems. Notably, the same equilibrium admits also a convergent integrable Chapman–Enskog series expansion around a leading-order Juttner distribution, which affords the analytical calculation of continuum fluid fields. In this reference, it is shown that the statistical average of total synchrotron power evaluated over the non-isotropic KDF differs significantly from the corresponding ensemble estimate that would be trivially obtained if the underlying velocity distribution were purely isotropic. It is pointed out that the knowledge of such a statistical discrepancy on the radiation-power curve could provide an independent framework for the characterization of the physical properties of the relativistic plasma state or of the background magnetic field that permeates these astrophysical scenarios.

Key role of microbial necromass and iron minerals in retaining micronutrients and facilitating biological nitrogen fixation in paddy soils

Paddy fields, as the largest anthropogenic wetlands on Earth, face a high risk of micronutrient loss through surface runoff and leaching due to their frequent irrigation-drainage cycles, as well as removal with crop harvest. While micronutrient's losses largely impede biological nitrogen fixation (BNF) in soils, agricultural practices and mechanisms that retain micronutrients and thus increase BNF in paddy soils remain underexplored. Here we showed that the long-term (40 years) application of fertilizers increased the contents of microbial necromass in paddy soils by 20%-43% compared to the unfertilized control. In particular, long-term organic fertilizations increased poorly crystalline minerals through intensifying mineral weathering, which further contributed to the increased stable carbon burials in paddy soils. Synchrotron radiation based spectromicroscopy analysis provided direct evidence demonstrating a differential control of mineral hydroxyl on C functional groups at the submicron scale in paddy soils. Notably, microbial necromass and short-range ordered minerals had a strong correlation with the content and bioavailability of micronutrients in paddy soils, indicating their key roles in the retention of micronutrients. Metagenomic sequencing analysis further indicated that the content and bioavailability of micronutrients were strongly correlated with the abundance of the key N-fixing genera (i.e., Azospirillum and Bradyrhizobium). Unexpectedly, structural equation modeling (SEM) identified that microbial necromass exerted the strongest control on N-fixing genera, highlighting an underappreciated role of microbial necromass as a reservoir of micronutrients. Based on micronutrient's bioavailability and metagenomic sequencing, we conclude that micronutrients are the key factor for BNF in paddy soils, offering significant implications for managing BNF in paddy soils.

Automatic Analysis and Anomaly Detection System of Transverse Electron Beam Profile Based on Advanced and Interpretable Deep Learning Architectures

Abstract The National Synchrotron Radiation Center SOLARIS, ranked among the top infrastructures of that type worldwide, is the only one located in Central-Eastern Europe, in Poland. The SOLARIS Center, with six fully operational beamlines, serves as a hub for research across a diverse range of disciplines. This cutting-edge facility fosters innovation in fields like biology, chemistry, and physics as well as material engineering, nanotechnology, medicine, and pharmacology. With its advanced infrastructure and multidisciplinary approach, the SOLARIS Center enables discoveries and pushes the boundaries of knowledge. The most important aspect of such enormous research as well as industry infrastructure is to provide stable working conditions for the users and the conducted projects. Due to its unique properties, problem complexities, and challenges that require advanced approaches, the problem of anomaly detection and automatic analysis of signals for the beam stability assessment is still a huge challenge that has not been fully developed. To increase the effectiveness of centers with advanced research infrastructure we focus on the automatic analysis of transverse beam profiles generated by the Pinhole diagnostic beam-line. Pinhole beamlines are typically installed in the middle and high-energy synchrotrons to thoroughly analyze emitted X-rays and therefore assess electron beam quality. To address the problem we take advantage of AI solutions including up-to-date pre-trained convolutional neural network (CNN) models among others EfficientNetB0-B4-B6, InceptionV3 and DenseNet121. In this research, we propose the benchmark for Pinhole image classification including data preprocessing, model implementation, training process, hyperparameter selection as well as testing phase. Created from scratch database contains over one million transverse beam profile images. The proposed solution, based on the InceptionV3 architecture, classifies pinhole beamline images with 94.1% accuracy and 96.6% precision which is a state-of-the-art result in this research area. Finally, we employed interpretability algorithms to perform an analysis of the models and achieved results.

Research and optimization of flow-induced vibrations in a water-cooled monochromator.

To enhance the stability of the water-cooled double-crystal monochromator used at the BL17B beamline of the Shanghai Synchrotron Radiation Facility (SSRF), a study was conducted to optimize its cooling system's flow-induced vibration. Through simulation and experimental verification, the researchers analyzed the vibration mechanism and implemented improvement measures. The results indicate that the elastic bellows greatly amplify flow-induced vibration, transmitting it to the first-crystal. By positioning the bellows closer to the crystal, the relative pitch angular vibration of the double-crystal was reduced by 17.5%, and the roll angular vibration decreased by 6.1%. Furthermore, changing the flow rate from 3 to 2.4 l/min further diminished the relative pitch angular vibration by 6.0% and the roll angular vibration by 7.9%. By effectively reducing flow-induced vibration in the water-cooled double-crystal monochromator, equipment stability is enhanced, and the relative angular vibration of the double-crystal has been reduced. This research provides a valuable method and approach for optimizing the stability of the monochromator and related equipment.

Polarized images of charged particles in vortical motions around a magnetized Kerr black hole

In this work, we study the images of a Kerr black hole (BH) immersed in uniform magnetic fields, illuminated by the synchrotron radiation of charged particles in the jet. We particularly focus on the spontaneously vortical motions (SVMs) of charged particles in the jet region and investigate the polarized images of electromagnetic radiations from the trajectories along SVMs. We notice that there is a critical value ω_c for charged particle released at a given initial position and subjected an outward force, and once |qB_0/m|=|ω_B|>|ω_c| charged particles can move along SVMs in the jet region. We obtain the polarized images of the electromagnetic radiations from the trajectories along SVMs. Our simplified model suggests that the SVM radiations can act as the light source to illuminate the BH and form a photon ring structure.

Translating microcalcification biomarker information into the laboratory: A preliminary assessment utilizing core biopsies obtained from sites of mammographic calcification

Rationale and objectivesThe potential of breast microcalcification chemistry to provide clinically valuable intelligence is being increasingly studied. However, acquisition of crystallographic details has, to date, been limited to high brightness, synchrotron radiation sources. This study, for the first time, evaluates a laboratory-based system that interrogates histological sections containing microcalcifications. The principal objective was to determine the measurement precision of the laboratory system and assess whether this was sufficient to provide potentially clinical valuable information. Materials and methodsSections from 5 histological specimens from breast core biopsies obtained to evaluate mammographic calcification were examined using a synchrotron source and a laboratory-based instrument. The samples were chosen to represent a significant proportion of the known breast tissue, mineralogical landscape. Data were subsequently analysed using conventional methods and microcalcification characteristics such as crystallographic phase, chemical deviation from ideal stoichiometry and microstructure were determined. ResultsThe crystallographic phase of each microcalcification (e.g., hydroxyapatite, whitlockite) was easily determined from the laboratory derived data even when a mixed phase was apparent. Lattice parameter values from the laboratory experiments agreed well with the corresponding synchrotron values and, critically, were determined to precisions that were significantly greater than required for potential clinical exploitation. ConclusionIt has been shown that crystallographic characteristics of microcalcifications can be determined in the laboratory with sufficient precision to have potential clinical value. The work will thus enable exploitation acceleration of these latent microcalcification features as current dependence upon access to limited synchrotron resources is minimized.

Modeling of Radio Supernovae: Including the Effects of Inhomogeneities and Radiative Cooling

The presence of inhomogeneities in a spatially unresolved source is often hard to establish. This limits the accuracy with which the source properties can be determined. It is shown how observed features not expected for a homogeneous model can be used to infer the properties of the inhomogeneities in radio supernovae. Furthermore, the observed consequences of radiative cooling can be seriously affected by inhomogeneities. It is shown that the deduced source properties are very sensitive to the observed value of the cooling frequency; even a lower limit is often useful to constrain its characteristics. It is argued that the main synchrotron emission region in SN 2003L has a small volume filling factor, possibly as low as a few percent. On the contrary, deviations from homogeneity are substantially smaller in SN 2002ap. The observed properties of Type Ib/c radio supernovae in general indicate the volume filling factor to remain rather constant with time for individual sources, but those peaking later at radio frequencies have lower filling factors. The conditions in the main synchrotron component in both SN 2003L and SN 2002ap are consistent with equipartition of energy between relativistic electrons and magnetic fields.

Modeling Blazar Broadband Emission with a Convolutional Neural Network. I. Synchrotron Self-Compton Model

Modeling the multiwavelength spectral energy distributions (SEDs) of blazars provides key insights into the underlying physical processes responsible for the emission. While SED modeling with self-consistent models is computationally demanding, it is essential for a comprehensive understanding of these astrophysical objects. We introduce a novel, efficient method for modeling the SEDs of blazars by the mean of a convolutional neural network (CNN). In this paper, we trained the CNN on a leptonic model that incorporates synchrotron and inverse Compton emissions, as well as self-consistent electron cooling and pair creation–annihilation processes. The CNN is capable of reproducing the radiative signatures of blazars with high accuracy. This approach significantly reduces the computational time, thereby enabling real-time fitting to multiwavelength data sets. As a demonstration, we used the trained CNN with MultiNest to fit the broadband SEDs of Mrk 421 and 1ES 1959+650, successfully obtaining their parameter posterior distributions. This novel framework for fitting the SEDs of blazars will be further extended to incorporate more sophisticated models based on external Compton and hadronic scenarios, allowing for multimessenger constraints in the analysis. The models will be made publicly available via a web interface at the Markarian Multiwavelength Data Center to facilitate self-consistent modeling of multimessenger data from blazar observations.

EUV durability of CNT pellicles for next-generation scanner

The pellicle plays a crucial role in the EUV photolithography process and has garnered increased attention from advanced semiconductor manufacturers as they strive to advance development for smaller process nodes. Carbon nanotubes (CNTs) are highly promising for EUV pellicle applications due to their exceptional mechanical, thermal, and optical properties. It is necessary for the pellicle to be durable and robust enough to withstand extreme scanner conditions, which involve combinations of high temperatures and active hydrogen species generated by EUV light. In this study, we present test results conducted to simulate the environment of the next-generation 600 W scanner using the NewSUBARU synchrotron light source facility. Our investigation focused on evaluating the performance of CNT films, both with and without protective coating layers. Surprisingly, the results indicate that the CNT film without coating demonstrated the most promising characteristics for pellicle applications, showcasing superior performance in the demanding EUV scanner environment.

A Study on the Nanostructural Evolution of Bi/C Anode Materials during Their First Charge/Discharge Processes.

As a candidate anode material for Li-ion batteries, Bi-based materials have attracted extensive attention from researchers due to their high specific capacity, environmental friendliness, and simple synthesis methods. However, Bi-based anode materials are prone to causing large volume changes during charging and discharging processes, and the effect of these changes on lithium storage performance is still unclear. This work introduces that Bi/C nanocomposites are prepared by the Bi-based MOF precursor calcination method, and that the Bi/C nanocomposite maintains a high specific capacity (931.6 mAh g-1) with good multiplicative performance after 100 cycles at a current density of 100 mA g-1. The structural evolution of Bi/C anode material during the first cycle of charging and discharging is investigated using in situ synchrotron radiation SAXS. The SAXS results indicate that the multistage scatterers of Bi/C composite, used as an anode material during the first lithiation, can be classified into mesopores, interspaces, and Bi nanoparticles. The different nanostructure evolutions of three types of Bi nanoparticles were observed. It is believed that this result will help to further understand the complex reaction mechanism of Bi-based anode materials in Li-ion batteries.

Charging modulation of the pyridine nitrogen of covalent organic frameworks for promoting oxygen reduction reaction

Covalent organic frameworks (COFs) are ideal templates for constructing metal-free catalysts for the oxygen reduction reaction due to their highly tuneable skeletons and controllable porous channels. However, the development of highly active sites within COFs remains challenging due to their limited electron-transfer capabilities and weak binding affinities for reaction intermediates. Herein, we constructed highly active catalytic centres by modulating the electronic states of the pyridine nitrogen atoms incorporated into the frameworks of COFs. By incorporating different pyridine units (such as pyridine, ionic pyridine, and ionic imidazole units), we tuned various properties including dipole moments, reductive ability, hydrophilicity, and binding affinities towards reaction intermediates. Notably, the ionic imidazole COF (im-PY-BPY-COF) exhibited greater activity than the neutral COF (PY-BPY-COF) and ionic pyridine COF (ion-PY-BPY-COF). Specifically, im-PY-BPY-COF demonstrated a half-wave potential of 0.80 V in 0.1 M KOH, outperforming other metal-free COFs. Theoretical calculations and in situ synchrotron radiation Fourier transform infrared spectroscopy confirmed that the carbon atoms in the ionic imidazole rings improved the activity by facilitating binding of the intermediate OOH* and promoting the desorption of OH*. This study provides new insights into the design of highly active metal-like COF catalysts.

Synchrotron signatures of cosmic ray transport physics in galaxies

ABSTRACT Cosmic rays (CRs) may drive outflows and alter the phase structure of the circumgalactic medium, with potentially important implications on galaxy formation. However, these effects ultimately depend on the dominant mode of transport of CRs within and around galaxies, which remains highly uncertain. To explore potential observable constraints on CR transport, we investigate a set of cosmological fire-2 CR-magnetohydrodynamic simulations of L* galaxies which evolve CRs with transport models motivated by self-confinement (SC) and extrinsic turbulence (ET) paradigms. To first order, the synchrotron properties diverge between SC and ET models due to a CR physics-driven hysteresis. SC models show a higher tendency to undergo ‘ejective’ feedback events due to a runaway buildup of CR pressure in dense gas due to the behaviour of SC transport scalings at extremal CR energy densities. The corresponding CR wind-driven hysteresis results in brighter, smoother, and more extended synchrotron emission in SC runs relative to ET and constant diffusion runs. The differences in synchrotron arise from different morphology, interstellar medium gas, and B properties, potentially ruling out SC as the dominant mode of CR transport in typical star-forming L* galaxies, and indicating the prospect for non-thermal radio continuum observations to constrain CR transport physics.

Development of magnesium alloys: Advanced characterization using synchrotron radiation techniques

Magnesium alloys are the lightest metal structural materials owing to their excellent physical and chemical properties. Microstructural evolution in magnesium alloys under the conditions of casting, thermal-mechanical processing, and in-service environment, play an important role in governing their mechanical properties and reliability/sustainability. A synchrotron light source produces high flux, tunable X-ray energy, high resolution, and high coherence X-ray beams, which can realize in-situ dynamic observation of microstructural evolution in a wide range of alloys during the entire processing chain and in simulated service environments. This article reviews the fundamentals of synchrotron radiation characterization techniques (imaging, diffraction, scattering, and fluorescence holography) and state-of-the-art advanced synchrotron characterization techniques on the microstructure evolution mechanism of magnesium alloys. Case studies span a broad range of solidification, deformation, precipitation, fracture and damage, corrosion, and energy storage. Research opportunities and challenges of physical metallurgy studies of magnesium alloys are highlighted for future studies.

Design and experiment of conduction cooling HTS current leads suited for superconducting Wiggler magnets

The cryogenic system of the 6T superconducting Wiggler magnets at the Hefei National Synchrotron Radiation Laboratory was upgraded. During the upgrade process, the original copper leads of the superconducting Wiggler magnets are replaced with two 460A high-temperature superconducting current leads and three 20A high-temperature superconducting current leads, reducing the heat load of the cryogenic system. Five HTS current leads can be cooled using a GM cryocooler based on the optimal design and experimental verification of their current-carrying capability and heat load. According to the loading current experimental data, the running voltage and operating temperature are stable. The results of the overcurrent capacity experiments demonstrate that the maximum loading current of the 20A high-temperature superconducting current lead can reach 142A and that of the 460A high-temperature superconducting current lead can reach 780A.

Commissioning of Bunch Compressor to Compress Space Charge-Dominated Electron Beams for THz Applications

The high peak current of the electron beam was found to be the key parameter for the THz SASE FEL at the Photo Injector Test facility at DESY in Zeuthen (PITZ). A multipurpose bunch compressor was implemented at PITZ to expand the parameter space of proof-of-principle studies on the tunable high-power accelerator-based THz source for pump-probe experiments at the European XFEL. The magnetic chicane, consisting of four rectangular dipole magnets, is designed with a bending angle of 19 degrees, due to limited space in the PITZ original beamline, to compress electron bunches with a beam momentum of 15–20 MeV/c and a charge up to 2 nC. The space charge effect and coherent synchrotron radiation are expected to drastically affect the bunch compressor performance for these parameters, thereby challenging the beam transport throughout the bunch compressor. A staged commissioning strategy was developed in order to achieve optimum bunch compressor operation. The first commissioning procedure establishes electron beam transport throughout the reference path and provides minimum beam momentum dispersion after the bunch compressor. This procedure yielded correlations between dipole magnet currents. As a result, the first bunch compression experiments were performed.

Characterization of nitrided SiC(1 [formula omitted] 00) MOS structures by means of electrical measurements and X-ray photoelectron spectroscopy

Interface nitridation in nitric oxide is a standard technique for improving the performance of silicon carbide (SiC) metal-oxide-semiconductor (MOS) devices. In this study, we focused on m-face SiC MOS structures and investigated the impact of nitridation by means of electrical measurements and X-ray photoelectron spectroscopy (XPS). Gate leakage characteristics were measured in a wide temperature range of about −150 – 100 °C, which clarified that nitridation leads to an unwanted increase in the Fowler-Nordheim leakage current. Scanning XPS measurements revealed that the amount of nitrogen incorporated at the m-face MOS interface could reach about 2.3 times higher than the Si-face MOS interface. The incorporation of nitrogen likely reduces the conduction band offset at the SiO2/SiC interface, thereby increasing the gate leakage. This conclusion was further corroborated in an analysis of band alignment based on synchrotron radiation XPS measurements. Therefore, while nitrided m-face SiC MOS devices exhibit superior on-state performances, they have a limitation in terms of reliability.