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The BL17B beamline at the Shanghai Synchrotron Radiation Facility was first designed as a versatile high‐throughput protein crystallography beamline and one of five beamlines affiliated to the National Facility for Protein Science in Shanghai. It was officially opened to users in July 2015. As a bending magnet beamline, BL17B has the advantages of high photon flux, brightness, energy resolution and continuous adjustable energy between 5 and 23 keV. The experimental station excels in crystal screening and structure determination, providing cost‐effective routine experimental services to numerous users. Given the interdisciplinary and green energy research demands, BL17B beamline has undergone optimization, expanded its range of experimental methods and enhanced sample environments for a more user‐friendly testing mode. These methods include single‐crystal X‐ray diffraction, powder crystal X‐ray diffraction, wide‐angle X‐ray scattering, grazing‐incidence wide‐angle X‐ray scattering (GIWAXS), and fully scattered atom pair distribution function analysis, covering structure detection from crystalline to amorphous states. This paper primarily presents the performance of the BL17B beamline and the application of the GIWAXS methodology at the beamline in the field of perovskite materials. [ABSTRACT FROM AUTHOR]

Benefiting from the development of high‐brilliance synchrotron radiation sources, microbeam X‐ray scattering has become a well established scattering‐based imaging technology. This article describes the newly constructed time‐resolved microbeam small‐angle X‐ray scattering (µSAXS) experimental station at the BL10U1 beamline at the Shanghai Synchrotron Radiation Facility. The µSAXS endstation provides SAXS/WAXS measurements with a 10 µm hard X‐ray beam and a flux of ∼1012 photons s−1. A multi‐axis sample stage, an on‐axis viewer and in situ experimental apparatus are incorporated to facilitate multi‐method scientific experiments in various material fields. As scientific examples, this article explores 1D tomography, 2D mapping and tomographic sectioning based on X‐ray scattering to investigate the micro–nanostructures of polymer fiber, spherulite and bamboo samples. [ABSTRACT FROM AUTHOR]

Following the rapid growth in accelerator-based light sources research since the mid of 20th century, miscellaneous third generation synchrotron radiation (SR) facilities such as SSRL, APS, ESRF, PETRA-III, and SPring-8 have come into existence. These SR source facilities provide 1020–1025 photons/s/mrad2/mm2/0.1%BW peak brightness within the photon energy range of 10–105 eV. Since different measurement techniques are utilized at X-ray beamlines of SR facilities, many kinds of insertion devices (i.e., undulators and wigglers) and optical components (e.g., high-resolution monochromators, double-crystal monochromators, lenses, mirrors, etc.) are employed for each experimental setup as a matter of course. Under the circumstances, optimization of a synchrotron beamline is a big concern for many scientists to ensure required radiation characteristics (i.e., photon flux, spot size, photon energy, etc.) for dedicated user experiments. In this respect, an in-vacuum hybrid undulator driven by a 6 GeV synchrotron electron beam is optimized using evolutionary algorithms (EA). Finally, it is shown that EA results are well consistent with both the literature and the analytical calculations, resulting in a promising design estimation for beamline scientists. [ABSTRACT FROM AUTHOR]

Internal shocks are a leading candidate for the dissipation mechanism that powers the prompt γ-ray emission in gamma-ray bursts (GRBs). In this scenario a compact central source produces an ultra-relativistic outflow with varying speeds, causing faster parts or shells to collide with slower ones. Each collision produces a pair of shocks – a forward shock (FS) propagating into the slower leading shell and a reverse shock (RS) propagating into the faster trailing shell. The RS's lab-frame speed is always smaller, while the RS is typically stronger than the FS, leading to different conditions in the two shocked regions that both contribute to the observed emission. We show that optically thin synchrotron emission from both (weaker FS + stronger RS) can naturally explain key features of prompt GRB emission such as the pulse shapes, time evolution of the ν F ν peak flux and photon energy, and the spectrum. Particularly, it can account for two features commonly observed in GRB spectra: (i) a sub-dominant low-energy spectral component (often interpreted as 'photospheric'-like), or (ii) a doubly broken power-law spectrum with the low-energy spectral slope approaching the slow-cooling limit. Both features can be obtained while maintaining high-overall radiative efficiency without any fine tuning of the physical conditions. [ABSTRACT FROM AUTHOR]

This article provides an overview of the upgrade of the Swiss Light Source (SLS) synchrotron facility at the Paul Scherrer Institute in Switzerland. The upgrade, known as SLS 2.0, aims to improve the facility's performance by implementing new technologies such as multibend achromats and higher storage-ring energy. The article discusses the X-ray sources at SLS 2.0, including bending magnets and insertion devices, with innovations and upgrades being made for the undulators. The beamlines at SLS 2.0 are also undergoing changes, with upgrades in optics and the addition of new beamlines. The timeline for the project is provided, with full user operation expected after the completion of the upgrades. [Extracted from the article]

N 157B located in the Large Magellanic Cloud is the first pulsar wind nebula detected outside of the Galaxy in γ-rays. In this paper, we analyse the emission above 30 GeV from N 157B using ∼14.3 yr of Fermi -LAT data. The γ-ray spectrum between 30 and 500 GeV is well described by a single power-law function with a photon index of 1.83 ± 0.26, and its integral photon flux is (4.10 ± 0.83) × 10−11 photons cm−2 s−1. We adopt a one-zone leptonic model to investigate whether the multiband non-thermal emission of the target source can be generated by synchrotron radiation and inverse-Compton scattering of the electrons/positrons. Assuming the electrons/positrons in the nebula have a broken power-law spectrum with two breaks, the model can reproduce the observed fluxes in the radio, X-ray, and γ-ray bands. This result indicates that the γ-ray emission from N 157B can be explained by the leptonic process of electrons/positrons via inverse-Compton scattering. [ABSTRACT FROM AUTHOR]

Metal halide perovskites (MHPs) are semiconductors with promising application in optoelectronic devices, particularly, in solar cell technologies. The chemical and electronic properties of MHPs at the surface and interfaces with adjacent layers dictate charge transfer within stacked devices and ultimately the efficiency of the latter. X‐ray photoelectron spectroscopy is a powerful tool to characterize these material properties. However, the X‐ray radiation itself can potentially affect the MHP and therefore jeopardize the reliability of the obtained information. In this work, the effect of X‐ray irradiation is assessed on Cs0.05MA0.15FA0.8Pb(I0.85Br0.15)3 (MA for CH3NH3, and FA for CH2(NH2)2) MHP thin‐film samples in a half‐cell device. There is a comparison of measurements acquired with synchrotron radiation and a conventional laboratory source for different times. Changes in composition and core levels binding energies are observed in both cases, indicating a modification of the chemical and electronic properties. The results suggest that changes observed over minutes with highly brilliant synchrotron radiation are likely occurring over hours when working with a lab‐based source providing a lower photon flux. The possible degradation pathways are discussed, supported by steady‐state photoluminescence analysis. The work stresses the importance of beam effect assessment at the beginning of XPS experiments of MHP samples. [ABSTRACT FROM AUTHOR]

The electrical‐substitution cryogenic detector BOLometer for Use in the range of X‐rays (BOLUX), which was developed some years ago at CEA/DAM, has been set up and restarted now at LNHB. It has been used for the primary measurement of the intensity (total energy per unit time) of monochromatic synchrotron beams in the energy range from 3 to 30 keV. These well‐determined photon beams have been employed for the efficiency calibration of two photodiodes in terms of current induced per unit optical power at different photon energies. In a final step, we explored the possibility to use these primary‐calibrated photodiodes to determine the efficiency curve of an energy‐dispersive spectrometer based on a semiconductor detector (Silicon Drift Detector) using less intense monochromatic photon fluxes. The characteristics of the radiometer BOLUX and its principle of operation are described, and the measurements carried out at the synchrotron beamline are presented, including the determination of the beams' intensities, the direct calibration of photodiodes with respect to BOLUX and the use of one of those photodiodes as a standard transfer for the calibration of the SDD. [ABSTRACT FROM AUTHOR]

The article provides an overview of the synchrotron radiation calculation code SPECTRA, which is used to evaluate the characteristics of synchrotron radiation. It discusses the history of the code's development, including challenges and limitations of earlier versions, and highlights new functions and improvements in the current version. The article also mentions special features of SPECTRA for beamline design. Additionally, the text discusses computational methods used to evaluate synchrotron radiation in a third-generation facility and introduces a simplified method for performing the coherent mode decomposition. The article concludes by mentioning that the SPECTRA code is available for use on the official website. [Extracted from the article]

Synchrotrons are brilliant sources of X-ray radiation used in a variety of methods to study the structure of matter and dynamics of processes on the atomic scale. X-ray spectroscopy methods at synchrotrons are typically combined with the beam monochromatization which guarantees better energy resolution but also reduces orders of magnitude the photon flux incident on the sample and thus wastes the vast majority of the photons produced. Here we report on the commissioning of an X-ray spectrometer at the PolyX beamline of SOLARIS specialized in application of white, broadband and monochromatic X-ray beam in multimodal microimaging, microtomography and microscpectroscopic studies. The spectrometer was used to acquire good quality Fe K-edge X-ray absorption spectrum over about 120 eV-range within seconds. In this work we present the first X-ray absorption spectrum measured using a synchrotron white beam in combination with a von Hámos geometry-based spectrometer. [ABSTRACT FROM AUTHOR]

Microwave-plasma undulator (MPU), as a standard short-period length undulator, is a desirable source of hard X-ray with continuous wide spectrum. In this article, the electron wiggling motion under the effect of transverse electric mode, propagating in cold plasma-filled waveguide, is investigated. The deflection parameter and period length of MPU in counter-propagating and co-propagating modes are calculated. Advantages of MPU over conventional and microwave undulators are investigated. It is shown that MPUs generate higher photon flux with overlapping harmonics compared to conventional standard undulators and cover wider energy range of synchrotron radiation. A rectangular MPU with period length of 2.98 mm and deflection parameter of 2.23 and a circular MPU with period length of 2.99 mm and deflection parameter of 2.23 are introduced. Also, a short variable period MPU, with the period length varying from 2.62 mm to 4.12 mm, and a helical MPU is introduced. [ABSTRACT FROM AUTHOR]

Combining wave optics propagation and geometric ray tracing, the mutual optical intensity (MOI) model is extended to quantitatively simulate the propagation of partially coherent light through a kinoform lens at high speed. The MOI model can provide both a high accuracy and a high efficiency simulation. The intensity and coherence degree distributions at the focal plane are calculated using the MOI model. It is beneficial to improve the focusing capability of the kinoform lens by reducing the coherence or increasing the number of lens steps. In addition, increasing the number of steps is also beneficial to increase the photon flux and reduce the depth of focus. [ABSTRACT FROM AUTHOR]

Synchrotron radiation based dynamic micro-computed tomography (micro-CT) is a powerful technique available at synchrotron light sources for investigating evolving microstructures. Wet granulation is the most widely used method of producing pharmaceutical granules, precursors to products like capsules and tablets. Granule microstructures are known to influence product performance, so this is an area for potential application of dynamic CT. Here, lactose monohydrate (LMH) was used as a representative powder to demonstrate dynamic CT capabilities. Wet granulation of LMH has been observed to occur on the order of several seconds, which is too fast for lab-based CT scanners to capture the changing internal structures. The superior X-ray photon flux from synchrotron light sources makes sub-second data acquisition possible and well suited for analysis of the wet-granulation process. Moreover, synchrotron radiation based imaging is non-destructive, does not require altering the sample in any way, and can enhance image contrast with phase-retrieval algorithms. Dynamic CT can bring insights to wet granulation, an area of research previously only studied via 2D and/or ex situ techniques. Through efficient dataprocessing strategies, dynamic CT can provide quantitative analysis of how the internal microstructure of an LMH granule evolves during the earliest moments of wet granulation. Here, the results revealed granule consolidation, the evolving porosity, and the influence of aggregates on granule porosity. [ABSTRACT FROM AUTHOR]

Angle-resolved photoemission spectroscopy with sub-micrometer spatial resolution (μ-ARPES), has become a powerful tool for studying quantum materials. To achieve sub-micrometer or even nanometer-scale spatial resolution, it is important to focus the incident light beam (usually from synchrotron radiation) using x-ray optics, such as the zone plate or ellipsoidal capillary mirrors. Recently, we developed a laser-based μ-ARPES with spin-resolution (LMS-ARPES). The 177 nm laser beam is achieved by frequency-doubling a 355 nm beam using a KBBF crystal and subsequently focused using an optical lens with a focal length of about 16 mm. By characterizing the focused spot size using different methods and performing spatial-scanning photoemission measurement, we confirm the sub-micron spatial resolution of the system. Compared with the μ-ARPES facilities based on the synchrotron radiation, our LMS-ARPES system is not only more economical and convenient, but also with higher photon flux (>5 × 1013 photons/s), thus enabling the high-resolution and high-statistics measurements. Moreover, the system is equipped with a two-dimensional spin detector based on exchange scattering at a surface-passivated iron film grown on a W(100) substrate. We investigate the spin structure of the prototype topological insulator Bi2Se3 and reveal a high spin-polarization rate, confirming its spin-momentum locking property. This lab-based LMS-ARPES will be a powerful research tool for studying the local fine electronic structures of different condensed matter systems, including topological quantum materials, mesoscopic materials and structures, and phase-separated materials. [ABSTRACT FROM AUTHOR]

A promising accelerator light source mechanism called steady-state microbunching (SSMB) is being actively studied. With the combination of strong coherent radiation from microbunching and high repetition rate of a storage ring, high-average-power narrow-band radiation can be anticipated from an SSMB storage ring, with wavelengths ranging from THz to soft X-ray. Such a novel light source could provide new opportunities for accelerator photon science like high-resolution angle-resolved photoemission spectroscopy and industrial applications like extreme ultraviolet (EUV) lithography. In this paper, a theoretical and numerical study of the average and statistical properties of coherent radiation from SSMB are presented. The results show that 1 kW average-power quasi-continuous-wave EUV radiation can be obtained from an SSMB ring provided that an average current of 1 A and a microbunch train with bunch length of 3 nm can be formed at the radiator which is assumed to be an undulator. Together with the narrow-band feature, the EUV photon flux can reach 6 × 1015 photons s-1 within a 0.1 meV energy bandwidth, which is three orders of magnitude higher than that in a conventional synchrotron source and is appealing for fundamental condensed matter physics and other research. In this theoretical investigation, we have generalized the definition and derivation of the transverse form factor of an electron beam which can quantify the impact of its transverse size on coherent radiation. In particular, it has been shown that the narrow-band feature of SSMB radiation is strongly correlated with the finite transverse electron beam size. Considering the pointlike nature of electrons and quantum nature of radiation, the coherent radiation fluctuates from microbunch to microbunch, or for a single microbunch from turn to turn. Some important results concerning the statistical properties of SSMB radiation are presented, with a brief discussion on its potential applications, for example the beam diagnostics. The presented work is of value for the development of SSMB to better serve potential synchrotron radiation users. In addition, this also sheds light on understanding the radiation characteristics of free-electron lasers, coherent harmonic generation, etc. [ABSTRACT FROM AUTHOR]

The project of the station of synchrotron radiation of the second stage Plamya-2 for the Siberian ring photon source SKIF is based on the experience gained during the development of the station "Plamya" on the storage ring VÉPP-4 at the Siberian Center for Synchrotron Radiation (SR). The station is designed to study the processes of combustion and thermal decomposition of various organic compounds by the method of photoionization mass spectrometry using vacuum ultraviolet (VUV) synchrotron radiation. The use of selective photoionization by VUV radiation in the molecular beam method of sampling from the reaction zone in flames or pyrolyzers makes it possible to identify and quantify the concentrations of atoms, radicals, and other labile and short-lived compounds, which provides key information on chemical transformations under conditions of high-speed combustion and thermal decomposition. The paper considers the possibility of using various SR generators available on the SKIF storage ring, as well as the optical scheme of the station and the conceptual design of its front-end. The experimental results of measuring photon fluxes for the Plamya station and the calculated photon fluxes on the sample for the Plamya-2 station are also presented. [ABSTRACT FROM AUTHOR]

BElChem-PGM The BElChem-PGM beamline will cover the soft X-ray energy range from approximately 90 eV to 2000 eV with a plane grating monochromator. One beamline, the undulator beamline U49/2 PGM (plane grating monochromator), covers the soft X-ray energy range, whereas the other dipole magnet sourced beamline, BElChem-DCM, with a double crystal monochromator (DCM), covers the tender X-ray energy range. The layout of the BElChem-PGM beamline is shown in Figure 2A. The optical elements and layout of the beamline have been optimized to deliver a high photon flux over a broad energy range, in particular at energies above 800 eV, with moderate spectral resolution. The Berlin Joint Lab for Electrochemical Interfaces (BElChem) is located at the BESSY II synchrotron in Berlin, Germany, and co-run by the Fritz-Haber-Institut, the Max-Planck-Institut of Chemical Energy Conversion and the Helmholtz-Zentrum Berlin. [Extracted from the article]

Rodents are used extensively as animal models for the preclinical investigation of microvascular‐related diseases. However, motion artifacts in currently available imaging methods preclude real‐time observation of microvessels in vivo. In this paper, a pixel temporal averaging (PTA) method that enables real‐time imaging of microvessels in the mouse brain in vivo is described. Experiments using live mice demonstrated that PTA efficiently eliminated motion artifacts and random noise, resulting in significant improvements in contrast‐to‐noise ratio. The time needed for image reconstruction using PTA with a normal computer was 250 ms, highlighting the capability of the PTA method for real‐time angiography. In addition, experiments with less than one‐quarter of photon flux in conventional angiography verified that motion artifacts and random noise were suppressed and microvessels were successfully identified using PTA, whereas conventional temporal subtraction and averaging methods were ineffective. Experiments performed with an X‐ray tube verified that the PTA method could also be successfully applied to microvessel imaging of the mouse brain using a laboratory X‐ray source. In conclusion, the proposed PTA method may facilitate the real‐time investigation of cerebral microvascular‐related diseases using small animal models. [ABSTRACT FROM AUTHOR]

In this paper, we describe the project of a photon source with energies up to 2500 MeV at the SKIF synchrotron radiation facility (under construction in Novosibirsk). It is intended for experiments on photonuclear reactions, nonlinear QED, EM detector calibration and other applications. A polarized photon beam with a flux of 106–108 Hz (in full spectrum) is produced using Compton backscattering (or inverse scattering) of IR, visible, and UV laser radiation, as well as the UV band of its own synchrotron radiation, on the SKIF electron beam (15 kHz). Spectrum monochromatization with collimators or/and tagging system by recoil electrons is possible. The discrepancy between experimental and theoretical photofission cross sections of actinide nuclei in a photon energy range of hundreds of MeV has been known since the 1980s, so it is proposed to study these cross sections in the first series of experiments. [ABSTRACT FROM AUTHOR]

The small time gaps of synchrotron radiation in conventional multi‐bunch mode (100–500 MHz) or laser‐based sources with high pulse rate (∼80 MHz) are prohibitive for time‐of‐flight (ToF) based photoelectron spectroscopy. Detectors with time resolution in the 100 ps range yield only 20–100 resolved time slices within the small time gap. Here we present two techniques of implementing efficient ToF recording at sources with high repetition rate. A fast electron‐optical beam blanking unit with GHz bandwidth, integrated in a photoelectron momentum microscope, allows electron‐optical 'pulse‐picking' with any desired repetition period. Aberration‐free momentum distributions have been recorded at reduced pulse periods of 5 MHz (at MAX II) and 1.25 MHz (at BESSY II). The approach is compared with two alternative solutions: a bandpass pre‐filter (here a hemispherical analyzer) or a parasitic four‐bunch island‐orbit pulse train, coexisting with the multi‐bunch pattern on the main orbit. Chopping in the time domain or bandpass pre‐selection in the energy domain can both enable efficient ToF spectroscopy and photoelectron momentum microscopy at 100–500 MHz synchrotrons, highly repetitive lasers or cavity‐enhanced high‐harmonic sources. The high photon flux of a UV‐laser (80 MHz, <1 meV bandwidth) facilitates momentum microscopy with an energy resolution of 4.2 meV and an analyzed region‐of‐interest (ROI) down to <800 nm. In this novel approach to 'sub‐µm‐ARPES' the ROI is defined by a small field aperture in an intermediate Gaussian image, regardless of the size of the photon spot. [ABSTRACT FROM AUTHOR]

Soft X‐rays excite the inner shells of materials more efficiently than any other form of light. The investigation of synchrotron radiation (SR) processes using inner‐shell excitation requires the beamline to supply a single‐color and high‐photon‐flux light in the soft X‐ray region. A new integrated computing multi‐layered‐mirror (MLM) monochromator was installed at beamline 07A (BL07A) of NewSUBARU, which has a 3 m undulator as a light source for irradiation experiments with high‐photon‐flux monochromatic light. The MLM monochromator has a high reflectivity index in the soft X‐ray region; it eliminates unnecessary harmonic light from the undulator and lowers the temperature of the irradiated sample surfaces. The monochromator can be operated in a high vacuum, and three different mirror pairs are available for different experimental energy ranges; they can be exchanged without exposing the monochromator to the atmosphere. Measurements of the photon current of a photodiode on the sample stage indicated that the photon flux of the monochromatic beam was more than 1014 photons s−1 cm−2 in the energy range 80–400 eV and 1013 photons s−1 cm−2 in the energy range 400–800 eV. Thus, BL07A is capable of performing SR‐stimulated process experiments. [ABSTRACT FROM AUTHOR]

Hard X-ray imaging with ultra-high speed acquisition rates using synchrotron-based sources or free-electron lasers has recently gained significant attention: commercially available CMOS-based cameras as basis for indirect detection allow for the use of radioscopy with MHz acquisition rates in a routine manner. Hence, an increasing number of experiments are reported in the literature studying with ultra-high speed radioscopy phenomena ranging from materials research (additive manufacturing), astrophysics (meteorite formation) to dynamic compression (propagation of shock and compression waves). By using the high flux beamline BL40XU of the SPring-8 synchrotron light source this MHz radioscopy approach has been developed further: the outstanding high photon flux density at narrow bandwidth of beamline BL40XU allowed for reaching unprecedented temporal resolution at high X-ray imaging sensitivity. Furthermore, a proto-type of a new ultra-high speed framing camera was integrated, demonstrating that frame rates close to the native radio frequency of the storage ring should become feasible in the future, i.e. an approach towards GHz radioscopy. [ABSTRACT FROM AUTHOR]

XIDer is a 2D pixelated hybrid X-ray detector that is supposed to act as a multi-purpose platform for diffraction experiments at fourth-generation high-energy synchrotron light sources like the Extremely Brilliant Source of the European Synchrotron Radiation Facility (ESRF-EBS). As such it needs to tackle a wide variety of requirements. These include x-ray energies of 30 keV to 100 keV imposing the utilisation of high-Z sensors, a wide dynamic range from single photons to fluxes of 1 × 109 photons pixel−1 s−1 and expected raw data rates up to the order of TB s−1 in the final detector design. As a result, XIDer's readout ASIC has to provide smart and flexible ways for on-chip data pre-processing to reduce the output data rate to manageable sizes. This article focusses on introducing the ASIC's novel and unique data-handling concepts like the custom-designed telegram protocol followed by the presentation of exemplary configurations and use cases. [ABSTRACT FROM AUTHOR]

Purpose: X‐ray microbeam radiation therapy is a preclinical concept for tumor treatment promising tissue sparing and enhanced tumor control. With its spatially separated, periodic micrometer‐sized pattern, this method requires a high dose rate and a collimated beam typically available at large synchrotron radiation facilities. To treat small animals with microbeams in a laboratory‐sized environment, we developed a dedicated irradiation system at the Munich Compact Light Source (MuCLS). Methods: A specially made beam collimation optic allows to increase x‐ray fluence rate at the position of the target. Monte Carlo simulations and measurements were conducted for accurate microbeam dosimetry. The dose during irradiation is determined by a calibrated flux monitoring system. Moreover, a positioning system including mouse monitoring was built. Results: We successfully commissioned the in vivo microbeam irradiation system for an exemplary xenograft tumor model in the mouse ear. By beam collimation, a dose rate of up to 5.3 Gy/min at 25 keV was achieved. Microbeam irradiations using a tungsten collimator with 50 μm slit size and 350 μm center‐to‐center spacing were performed at a mean dose rate of 0.6 Gy/min showing a high peak‐to‐valley dose ratio of about 200 in the mouse ear. The maximum circular field size of 3.5 mm in diameter can be enlarged using field patching. Conclusions: This study shows that we can perform in vivo microbeam experiments at the MuCLS with a dedicated dosimetry and positioning system to advance this promising radiation therapy method at commercially available compact microbeam sources. Peak doses of up to 100 Gy per treatment seem feasible considering a recent upgrade for higher photon flux. The system can be adapted for tumor treatment in different animal models, for example, in the hind leg. [ABSTRACT FROM AUTHOR]

Nanoprobe X‐ray diffraction (nXRD) using focused synchrotron radiation is a powerful technique to study the structural properties of individual semiconductor nanowires. However, when performing the experiment under ambient conditions, the required high X‐ray dose and prolonged exposure times can lead to radiation damage. To unveil the origin of radiation damage, a comparison is made of nXRD experiments carried out on individual semiconductor nanowires in their as‐grown geometry both under ambient conditions and under He atmosphere at the microfocus station of the P08 beamline at the third‐generation source PETRA III. Using an incident X‐ray beam energy of 9 keV and photon flux of 1010 s−1, the axial lattice parameter and tilt of individual GaAs/In0.2Ga0.8As/GaAs core–shell nanowires were monitored by continuously recording reciprocal‐space maps of the 111 Bragg reflection at a fixed spatial position over several hours. In addition, the emission properties of the (In,Ga)As quantum well, the atomic composition of the exposed nanowires and the nanowire morphology were studied by cathodoluminescence spectroscopy, energy‐dispersive X‐ray spectroscopy and scanning electron microscopy, respectively, both prior to and after nXRD exposure. Nanowires exposed under ambient conditions show severe optical and morphological damage, which was reduced for nanowires exposed under He atmosphere. The observed damage can be largely attributed to an oxidation process from X‐ray‐induced ozone reactions in air. Due to the lower heat‐transfer coefficient compared with GaAs, this oxide shell limits the heat transfer through the nanowire side facets, which is considered as the main channel of heat dissipation for nanowires in the as‐grown geometry. [ABSTRACT FROM AUTHOR]

Absolute measurement of photon flux under high‐fluence rate X‐rays was required in photon diagnostics for X‐ray lasers. A free‐air ionization chamber used for the reproducibility of air‐kerma in high‐fluence rate X‐ray was designed, and the monoenergetic X‐rays flux of (6–20) keV were absolutely measured on Beijing Synchrotron Radiation Facility. The energy spectrum of the monoenergetic X‐rays was measured using a silicon drift detector, and the proportion of higher harmonics was determined. The saturation curve, air attenuation correction factor, and composite loss correction factor of the free‐air ionization chamber were obtained experimentally. The air‐kerma rate for the (6~20) keV monoenergetic X‐ray was measured accurately, and the relative combined standard uncertainty of the air‐kerma is 0.61%. [ABSTRACT FROM AUTHOR]

Enhancement of X‐ray excited optical luminescence in a 100 µm‐thick diamond plate by introduction of defect states via electron beam irradiation and subsequent high‐temperature annealing is demonstrated. The resulting X‐ray transmission‐mode scintillator features a linear response to incident photon flux in the range 7.6 × 108 to 1.26 × 1012 photons s−1 mm−2 for hard X‐rays (15.9 keV) using exposure times from 0.01 to 5 s. These characteristics enable a real‐time transmission‐mode imaging of X‐ray photon flux density without disruption of X‐ray instrument operation. [ABSTRACT FROM AUTHOR]

We offer a theoretical and experimental study of the single-photon photoionization of Ne III. The high photon flux and the high-resolution capabilities of the Advanced Light Source at the LBNL were employed to measure absolute photoionization cross sections. The resulting spectrum has been benchmarked against high accuracy relativistic Breit-Pauli R -matrix calculations. A large close-coupling wave function expansion which comprises up to 58 fine-structure levels of the residual ion Ne IV of configurations 2 s 2 2 p 3 , 2 s 2 p 4 , 2 p 5 , 2 s 2 2 p 2 3 s , 2 s 2 2 p 2 3 p and 2 s 2 2 p 2 3 d was included. A complete identification of the measured features was achieved by considering seven low-lying levels of Ne III. We found that the photoionization cross-section ( σ P I ) exhibits the presence of prominent resonances in the low-energy region near the ionization thresholds that correspond to low-lying levels. These include high-peak narrow resonances with almost zero background introduced by relativistic effects. However, there does not exist a significant contribution to σ P I from relativistic effects at the high-energy interval of the present study. Image 1 • Accurate measurements of the single photoionization of oxygen-like Ne III ions. • Relativistic ab-initio R-matrix, Breit-Pauly calculations. • Auto-ionizing Rydberg series. • Cross section measurements. [ABSTRACT FROM AUTHOR]

The BL02B bending‐magnet beamline at the Shanghai Synchrotron Radiation Facility (SSRF) has been constructed and is now operational for ambient‐pressure photoelectron spectroscopy (APPES) and photon‐in/photon‐out spectroscopy (PIPOS) experimental use. Optical optimization was implemented for realization of high performance, e.g. photon flux, energy‐resolving power and focus spot size. X‐ray photoelectron spectroscopy experiments show that the energy range extends from 40 to 2000 eV. Argon, nitrogen and neon gas core‐shell excitation spectra indicate energy‐resolving powers of over 1.4 × 104 @ 244 eV, 1.0 × 104 @ 401 eV and 7.0 × 103 @ 867 eV, respectively. The measured photon flux is 1.3 × 1011 photons s−1 @ E/ΔE = 3700 at 244 eV at the expected sample position, for the SSRF electron energy of 3.5 GeV and electron current of 240 mA. The spot sizes are 177 µm × 23 µm and 150 µm × 46 µm at the APPES and PIPOS samples, respectively. The BL02B beamline with high energy resolution and high photon flux at the Shanghai Synchrotron Radiation Facility has been operating for APPES and PIPOS experimental use. [ABSTRACT FROM AUTHOR]

In this paper, a new beamline optical system design method is reported in which the calculation of synchrotron radiation source flux distribution, monochromator spectral resolving power, mirror reflectance and grating diffraction efficiency are integrated together in one program to evaluate the whole beamline optical system performance. We demonstrate the advantage of this method by applying it to the Surface Physics beamline at Hefei Light Source to find out better optical system parameters. By using this method, a higher photon flux with the same spectral resolving power than the original design is achieved. The integrated optical system design method provides a great promising application in the beamline optical design and optimization in the future. [ABSTRACT FROM AUTHOR]

An X‐ray prism for the extraction of a specific harmonic of undulator radiation is proposed. By using the prism in a grazing incidence geometry, the beam axes of fundamental and harmonics of undulator radiation are separated with large angles over 10 µrad, which enables the selection of a specific harmonic with the help of apertures, while keeping a high photon flux. The concept of the harmonic separation was experimentally confirmed using X‐ray beams from the X‐ray free‐electron laser SACLA. [ABSTRACT FROM AUTHOR]

Blazed gratings are of dedicated interest for the monochromatization of synchrotron radiation when a high photon flux is required, such as, for example, in resonant inelastic X-ray scattering experiments or when the use of laminar gratings is excluded due to too high flux densities and expected damage, for example at free-electron laser beamlines. Their availability became a bottleneck since the decommissioning of the grating manufacture facility at Carl Zeiss in Oberkochen. To resolve this situation a new technological laboratory was established at the Helmholtz Zentrum Berlin, including instrumentation from Carl Zeiss. Besides the upgraded ZEISS equipment, an advanced grating production line has been developed, including a new ultra-precise ruling machine, ion etching technology as well as laser interference lithography. While the old ZEISS ruling machine GTM-6 allows ruling for a grating length up to 170 mm, the new GTM-24 will have the capacity for 600 mm (24 inch) gratings with groove densities between 50 lines mm-1 and 1200 lines mm-1. A new ion etching machine with a scanning radiofrequency excited ion beam (HF) source allows gratings to be etched into substrates of up to 500 mm length. For a final at-wavelength characterization, a new reflectometer at a new Optics beamline at the BESSY-II storage ring is under operation. This paper reports on the status of the grating fabrication, the measured quality of fabricated items by ex situ and in situ metrology, and future development goals. [ABSTRACT FROM AUTHOR]

The SUT-NANOTEC-SLRI beamline was constructed in 2012 as the flagship of the SUT-NANOTEC-SLRI Joint Research Facility for Synchrotron Utilization, co-established by Suranaree University of Technology (SUT), National Nanotechnology Center (NANOTEC) and Synchrotron Light Research Institute (SLRI). It is an intermediate-energy X-ray absorption spectroscopy (XAS) beamline at SLRI. The beamline delivers an unfocused monochromatic X-ray beam of tunable photon energy (1.25-10 keV). The maximum normal incident beam size is 13 mm (width) × 1 mm (height) with a photon flux of 3 × 108 to 2 × 1010 photons s−1 (100 mA)−1 varying across photon energies. Details of the beamline and XAS instrumentation are described. To demonstrate the beamline performance, K-edge XANES spectra of MgO, Al2O3, S8, FeS, FeSO4, Cu, Cu2O and CuO, and EXAFS spectra of Cu and CuO are presented. [ABSTRACT FROM AUTHOR]

A new angle resolved photoelectron energy spectrum (ARPES) beamline is designed as a branch of the photoelectron experimental system (dreamline) at Shanghai Synchrotron Radiation Facility (SSRF). Its purpose is to provide a powerful instrument to conduct ARPES experiments for users from all over the world. During the design and construction of the beamline, many technical difficulties needed to be solved because of its high energy resolution, high photon flux and high focusing quality, including the design of monochromator, the design of Kirkpatrick–Baez (KB) mirror system and the manufacture of the optics. In this paper, the KB mirror system is described, including its principle and design scheme. The practical significance of displacement function is discussed. For vertical linear driving mechanism, the variation of resolution and repeatability induced by its axial deformation and radial deformation is analyzed. The results show that it is within the scope of permissible error. Linear resolution and repeatability, and angle resolution and repeatability are tested as 0.56 μm, 1.6 μm, 0.6″ and 1.08″, which guarantee the high accurate motion of KB mirrors and further improve the performance of the beamline. The simulation and ray tracing results of the beamline show that the energy resolution is better than 11.2 meV at 1000 eV, the photon flux is higher than 10 11 phs/s/0.01%BW and the spot size on sample is about 15 μm × 4.7 μm (FWHM), demonstrating that the performance is beyond prediction. [ABSTRACT FROM AUTHOR]

Commissioned in May 2004 on the SLS machine, the LUCIA beamline was moved to the synchrotron SOLEIL during the summer of 2008. To take advantage of this new setting several changes to its design were introduced. Here, a review of the various improvements of the mechanics and, mostly, of the optics is given. Described in detail are the results of a new multilayer grating monochromator implemented on the Kohzu vessel already holding the two-crystal set-up. It consists of a grating grooved onto a multilayer (replacing the first crystal) associated to a multilayer (as a second crystal). It allows a shift of the low-energy limit of the beamline to around 500 eV with an energy resolution and a photon flux comparable with those of the previous couples of crystals (KTP and beryl). [ABSTRACT FROM AUTHOR]

In the last five years, a strong experimental and theoretical activity has been dedicated to the study of inner-shell double photoionization. Almost simultaneously, between 2009 and 2011, different experiments were performed using two different light sources: well established third generation synchrotron light sources that exist for more than two decades and recently developed x-ray free electron lasers (X-FEL) that provide brightness of about 10 orders of magnitude higher. The high photon flux of X-FEL has made possible the successive absorption of many x-ray photons by inner-shell electrons in femtosecond timescale. The possibility to create multiple inner-shell vacancies with this new X-FEL light source has resuscitated “prophetic” 25 years old calculations by Cederbaum et al. [1,2] concerning double K-shell ionization that could be of great interest when conventional Electron Spectroscopy for Chemical Analysis (ESCA) finds some limitations. As a feedback, this has stimulated new theoretical developments. On the other hand, it was considered practically out of reach to observe such states with conventional third generation synchrotron light sources due to the very weak probability to eject two inner-shell electrons by a single photon when the dominant process, that could mask everything else, is single inner-shell ionization. However, due to the development of very efficient detection techniques, it was also possible to perform spectroscopy of double core-hole states with excellent accuracy using third generation synchrotron sources. In this paper we give an outlook on the basis of recently published results, of the complementarity of these light sources for double core-hole spectroscopy. Some new developments and results are also presented with a prospective of what could be done in the future with the technical breakthrough that will be necessary to improve our further understanding of chemical analysis. [ABSTRACT FROM AUTHOR]

A compact multi-functional diagnostic tool has been installed for commissioning beamlines at the Taiwan Light Source. For a photon beam, the instrument can measure the photon flux, energy resolution and beam size, consecutively with a photodiode or gold mesh, a windowless gas cell and a movable fluorescence screen viewport. Two gratings with ruling densities of 350 and 1000 lines mm−1 and dispersing photons of energies from 80 to 1200 eV were calibrated with a photon flux of 1011 photon s−1 at slit openings of 50 µm × 50 µm; a maximum resolving power of greater than 10000 was certified with an absorption spectra of gaseous samples. Pressure differences over four orders of magnitude were achieved between the ion chamber and the flux measurement chamber with a single capillary differential pumping stage. A sequence of beam profiles was measured by moving continuously in the vicinity of the nominal focal positions. This tool is useful in commissioning or trouble-shooting at most beamlines in a synchrotron facility. [ABSTRACT FROM AUTHOR]

A new monochromator is designed to develop a high performance soft X-ray microscopy beamline at Shanghai Synchrotron Radiation Facility (SSRF). But owing to its high resolving power and high accurate spectrum output, there exist many technical difficulties. In the paper presented, as two primary design targets for the monochromator, theoretical energy resolution and photon flux of the beamline are calculated. For wavelength scanning mechanism, primary factors affecting the rotary angle errors are presented, and the measuring results are 0.15" and 0.17" for plane mirror and plane grating, which means that it is possible to provide sufficient scanning precision to specific wavelength. For plane grating switching mechanism, the repeatabilities of roll, yaw and pitch angles are 0.08", 0.12" and 0.05", which can guarantee the high accurate switch of the plane grating effectively. After debugging, the repeatability of light spot drift reaches to 0.7", which further improves the performance of the monochromator. The commissioning results show that the energy resolving power is higher than 10000 at Ar L-edge, the photon flux is higher than 1 × 108 photons/sec/200 mA, and the spatial resolution is better than 30 nm, demonstrating that the monochromator performs very well and reaches theoretical predictions. [ABSTRACT FROM AUTHOR]

The maximum of the Wigner distribution (WD) of synchrotron radiation (SR) fields is considered as a possible definition of SR source brightness. Such a figure of merit was originally introduced in the SR community by Kim [(1986), Nucl. Instrum. Methods Phys. Res. A, 246, 71-76]. The brightness defined in this way is always positive and, in the geometrical optics limit, can be interpreted as the maximum density of photon flux in phase space. For undulator and bending magnet radiation from a single electron, the WD function can be explicitly calculated. In the case of an electron beam with a finite emittance the brightness is given by the maximum of the convolution of a single electron WD function and the probability distribution of the electrons in phase space. In the particular case when both electron beam size and electron beam divergence dominate over the diffraction size and the diffraction angle, one can use a geometrical optics approach. However, there are intermediate regimes when only the electron beam size or the electron beam divergence dominate. In these asymptotic cases the geometrical optics approach is still applicable, and the brightness definition used here yields back once more to the maximum photon flux density in phase space. In these intermediate regimes a significant numerical disagreement is found between exact calculations and the approximation for undulator brightness currently used in the literature. The WD formalism is extended to a satisfactory theory for the brightness of a bending magnet. It is found that in the intermediate regimes the usually accepted approximation for bending magnet brightness turns out to be inconsistent even parametrically. [ABSTRACT FROM AUTHOR]

In the 1–2 keV range, we adopted YB66 crystal for dispersing synchrotron radiation of the beamline No.15 (BL15XU) at SPring-8. YB66 crystal has a large d-value of 0.586 nm for the 4 0 0 reflection and is useful as a soft X-ray monochromator for dispersing synchrotron radiation, since there is no intrinsic absorption edge and it is more resistant than other crystals to synchrotron radiation damage. We investigated the resolution of the YB66 double-crystal monochromator and measured the photon flux passing through this monochromator. The full-width at half-maximum of the rocking curve ranged from 0.15 eV at 1.1 keV to 0.42 eV at 2.1 keV. The photon flux ranged from 6×108 photons/sec/100 mA measured at an experimental position at 1.1 keV to 5×109 photons/sec/100 mA measured at an experimental position at 2 keV. It is considered that the better energy resolution of the YB66 crystal was achieved by irradiating only a small restricted area of the crystal by an incident beam with small angular divergence originated from a helical undulator. [Copyright &y& Elsevier]

With the development of full-field transmission X-ray microscopy (TXM) for research in biology, life science, material science and physics, zone plate-based full-field TXM is becoming a powerful tool for obtaining quantitative internal structural and chemical information at the nanoscale when combined with spectroscopic imaging. For the TXM beamline design, the best choice is to match the phase space needed by the zone plate from the source point. However, for the nearly diffraction-limited synchrotron radiation sources, it is not easy to fully match the needed phase space due to its low-emittance. Using redshift radiation from an undulator, under consideration of experimental requirements and the heat load effect, this paper describes the design of TXM beamline at the nearly diffraction-limited High Energy Photon Source (HEPS). In this design, not only sufficient illumination angle can be acquired, but also a nearly annular illumination can be obtained to match the illumination required for zone plate imaging. Furthermore, about two times photon flux can be obtained at source point and the photons can be fully used in this design using redshift undulator radiation. The presented design can also be informative for the same kind of beamline design at other nearly diffraction-limited synchrotron photon sources. [ABSTRACT FROM AUTHOR]

Sources of high-energy photons have important applications in almost all areas of research. However, the photon flux and intensity of existing sources is strongly limited for photon energies above a few hundred keV. Here we show that a high-current ultrarelativistic electron beam interacting with multiple submicrometer-thick conducting foils can undergo strong self-focusing accompanied by efficient emission of gamma-ray synchrotron photons. Physically, self-focusing and high-energy photon emission originate from the beam interaction with the near-field transition radiation accompanying the beam-foil collision. This near field radiation is of amplitude comparable with the beam self-field, and can be strong enough that a single emitted photon can carry away a significant fraction of the emitting electron energy. After beam collision with multiple foils, femtosecond collimated electron and photon beams with number density exceeding that of a solid are obtained. The relative simplicity, unique properties, and high efficiency of this gamma-ray source open up new opportunities for both applied and fundamental research including laserless investigations of strong-field QED processes with a single electron beam. [ABSTRACT FROM AUTHOR]

New high-flux synchrotron radiation circular dichroism (SRCD) beamlines are providing important information for structural biology, but can potentially cause denaturation of the protein samples under investigation. This effect has been studied at the new CD1 dedicated SRCD beamline at ISA in Denmark, where radiation-induced thermal damage effects were observed, depending not only on the radiation flux but also on the focal spot size of the light. Comparisons with similar studies at other SRCD facilities worldwide has lead to the estimation of a flux density threshold under which SRCD beamlines should be operated when samples are to be exposed to low-wavelength vacuum ultraviolet radiation for extended periods of time. [ABSTRACT FROM AUTHOR]

A new photon-in/photon-out endstation at beamline 02B02 of the Shanghai Synchrotron Radiation Facility for studying the electronic structure of energy materials has been constructed and fully opened to users. The endstation has the capability to perform soft x-ray absorption spectroscopy in total electron yield and total fluorescence yield modes simultaneously. The photon energy ranges from 40 eV to 2000 eV covering the K-edge of most low Z-elements and the L-edge of 3d transition-metals. The new self-designed channeltron detector allows us to achieve good fluorescence signals at the low photon flux. In addition, we synchronously collect the signals of a standard reference sample and a gold mesh on the upstream to calibrate the photon energy and monitor the beam fluctuation, respectively. In order to cross the pressure gap, in situ gas and liquid cells for soft x-ray absorption spectroscopy are developed to study the samples under realistic working conditions. [ABSTRACT FROM AUTHOR]

Coronary angiography is clinically used worldwide to diagnose diseases of coronary arteries. Despite its effectiveness, this technique is quite invasive and it is associated with significant risks due to the arterial catheterisation needed to inject the contrast agent. A valid alternative is using the K-edge subtraction (KES) method, which is based on the subtraction of two images acquired at energies bracketing the K-edge of the contrast element. The enhanced sensitivity of KES allows the intravenous injection of the contrast agent, thus reducing the risks of catheterisation. This technique can be effectively implemented by using intense and quasi-monochromatic x-ray beams. Synchrotron radiation has been proven to work well for this purpose, but its cost and size prevent a widespread clinical application. Inverse Compton sources are among the most promising innovative sources of intense and quasi-monochromatic x-rays. These sources are intrinsically more compact than those based on synchrotron radiation. In this work, the potential application of inverse Compton radiation to KES angiography is investigated. To this purpose, after a short review of the physics behind the inverse Compton process, an analytical framework is described. The proposed model is based on the application of the KES algorithm to calculate the SNR of details inside a suitable mathematical phantom. That allowed us to identify the characteristics of an inverse Compton source required for KES imaging. In particular, it was estimated that a photon fluence of 108 ph mm−2 is necessary to detect signals of clinical interest. Novel sources based on inverse Compton promise to achieve this requirement with an acquisition time of few hundreds of ms. This feature, together with compactness, broad two-dimensional radiation field, absence of harmonic contamination and the ability to deliver high photon fluxes also at high energies, makes this kind of sources promising for KES angiography and other diagnostic applications. [ABSTRACT FROM AUTHOR]