High-brilliance Synchrotron Radiation Source Research Articles

A new experimental station for microbeam X-ray scattering at the SSRF BL10U1 beamline

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.

Study of ruthenium film grown in oxygen environment for x-ray optics application

Ru shows high damage threshold as compared to other standard materials Au, Rh and Pt for high heat load applications in high brilliance synchrotron radiation source and x-ray free electron laser. It is also a promising candidate to be used as a protective capping layer in multilayers for increasing their life time. In the present study, Ru thin films of 500Å thickness were deposited in oxygen environment at different substrate temperatures varying from 70°C to 500°C. In reactive ion beam sputtering process, the flow of Ar and reactive O2 gas was maintained in 4:1 ratio keeping total flow 3 SCCM constant. The deposited films were characterized using grazing incidence x-ray reflectivity (GIXRR), grazing incidence x-ray diffraction (GIXRD) and secondary ion mass spectroscopy (SIMS) techniques. A significant change in GIXRR profile was observed in the sample grown at 100°C and 500°C whereas the GIXRD measurements indicated no significant formation of ruthenium oxide at different temperatures. However, a strong peak of Ru2Si3 (222) at 500°C was observed indicating a strong interfacial reaction at ruthenium/ substrate interface.The experimental data suggested a weak signature of RuO2 phase in the films deposited at RT, 70°C and 100°C and therefore the effect of ruthenium oxide with 10% composition in pure ruthenium was calculated on optical performance in extreme ultra violet region of photon energy (85-115 eV).

Disentangling x-ray dichroism and birefringence via high-purity polarimetry

High-brilliance synchrotron radiation sources have opened new avenues for x-ray polarization analysis that go far beyond conventional polarimetry in the optical domain. With linear x-ray polarizers in a crossed setting, polarization extinction ratios down to 10 − 10 can be achieved. This renders the method sensitive to probe the tiniest optical anisotropies that would occur, for example, in strong-field quantum electrodynamics due to vacuum birefringence and dichroism. Here we show that high-purity polarimetry can be employed to reveal electronic anisotropies in condensed matter systems with utmost sensitivity and spectral resolution. Taking CuO and L a 2 C u O 4 as benchmark systems, we present a full characterization of the polarization changes across the Cu K-absorption edge and their separation into dichroic and birefringent contributions. At diffraction-limited synchrotron radiation sources and x-ray lasers, where polarization extinction ratios of 10 − 12 can be achieved, our method has the potential to assess birefringence and dichroism of the quantum vacuum in extreme electromagnetic fields.

Evolution of Complexity in Out-of-Equilibrium Systems by Time-Resolved or Space-Resolved Synchrotron Radiation Techniques

Out-of-equilibrium phenomena are attracting high interest in physics, materials science, chemistry and life sciences. In this state, the study of structural fluctuations at different length scales in time and space are necessary to achieve significant advances in the understanding of the structure-functionality relationship. The visualization of patterns arising from spatiotemporal fluctuations is nowadays possible thanks to new advances in X-ray instrumentation development that combine high-resolution both in space and in time. We present novel experimental approaches using high brilliance synchrotron radiation sources, fast detectors and focusing optics, joint with advanced data analysis based on automated statistical, mathematical and imaging processing tools. This approach has been used to investigate structural fluctuations in out-of-equilibrium systems in the novel field of inhomogeneous quantum complex matter at the crossing point of technology, physics and biology. In particular, we discuss how nanoscale complexity controls the emergence of high-temperature superconductivity (HTS), myelin functionality and formation of hybrid organic-inorganic supramolecular assembly. The emergent complex geometries, opening novel venues to quantum technology and to the development of quantum physics of living systems, are discussed.

Laboratory-based high pressure X-ray photoelectron spectroscopy: A novel and flexible reaction cell approach.

The last 10-15 years have witnessed a resurgence in the application of high pressure X-ray photoelectron spectroscopy, mainly through the development of new electron energy analyser designs and the utilization of high-brilliance synchrotron radiation sources. To continue this expansion of the technique, it is crucial that instruments are developed for the home-laboratory, considering that this is where the vast majority of traditional ultra-high vacuum (UHV) X-ray photoelectron spectroscopy is performed. The research presented here introduces a new addition to the field, an instrument capable of performing spectroscopy measurements from UHV to high pressure (25 mbar), achieved using a retractable and modular reaction cell design. The ease of use, stability (of analyser, X-ray source, and gas delivery, etc.), and overall capability of the instrument will be demonstrated.

Time-resolved soft X-ray microscopy of magnetic nanostructures at the P04 beamline at PETRA III

We present first time-resolved measurements of a new mobile full-field transmission microscope [1] obtained at the soft X-ray beamline P04 at the high brilliance synchrotron radiation source PETRA III.A nanostructured magnetic permalloy (Ni80Fe20) sample can be excited by the magnetic field of a 400 ps full width at half maximum (FWHM) long electric current pulse in a coplanar waveguide. The full-field soft X-ray microscope successively probes the time evolution of the sample magnetization via X-ray magnetic circular dichroism (XMCD) [2] spectromicroscopy in a pump-probe scheme by varying the delay between pump and probe pulses electronically. Static and transient magnetic fields of a permanent magnet and a coil are available in the sample plane to reset the system and to provide external offset fields.The microscope generates a flat-top illumination field of 20 μm diameter by using a grating condenser [3] and the sample plane is directly imaged by a micro zone plate with 60 nm resolution onto a 2D gateable X-ray detector to select the particular bunch in the storage ring that contains the dynamic information. The setup is built into a mobile endstation vacuum system with in-house developed three-axis piezo motorized stages for high accuracy positioning of all microscopy-components inside the chambers.

Effect of Fluorination on Membrane Interactions of an Antimicrobial Peptoid Macrocycle

The need for new antibiotics is of increasing importance as bacteria continue to develop resistance to conventional antibacterial agents in clinical use. A promising source of potential anti-infective agents have been reported for a family of antimicrobial peptide mimics known as peptoids. However, bioavailability, and target binding affinity are key factors in determining if a bioactive compound will establish effective therapeutic efficacy in vivo. A widely used strategy in drug design is to increase metabolic stability and lipophilicity by compound fluorination. In this investigation we compare the mechanism of action of the cyclic peptoid C(3-15) and its fluorinated analog C(3-2) on model bacteria membrane systems using a high brilliance synchrotron radiation source. We have employed X-ray reflectivity (XR) on two different Langmuir monolayers mimicking the outer membrane of Gram-positive and Gram-negative bacteria composed of 1,2-dipalmitoyl-sn-glycero-3-phospho (DPPG) and the lipopolysaccharide (LPS) LipidA-Kdo2 respectively. XR reveals that although both compounds insert readily into DPPG and LPS monolayers, the fluorinated peptoid shows a greater activity than its nonfluorinated analog.

Grain Tracking at the High Energy Materials Science Beamline of the Petra III Synchrotron Radiation Source

Grain tracking is a term used to describe experiments that investigate polycrystalline materials in terms of the crystallites or grains from which they are composed, non-destructively and in three dimensions. The new German high brilliance synchrotron radiation source, Petra III, will become available to users in 2010 [1]. The GKSS research centre will operate two beamlines, including the high energy materials science beamline (HEMS) [2]. HEMS will feature an instrument dedicated to grain tracking, able to support a range of experiments of this kind. This paper describes the design and specification of this instrument, and gives examples of the types of experiments that will be possible.

Hard x-ray photoelectron spectroscopy of oxide hybrid and heterostructures: a new method for the study of buried interfaces

Hard x-ray photoelectron spectroscopy (HAXPES) is a new variant of the well-established photoemission technique, which extends its range to much higher photoelectron energies up to 10 keV and thus to enhanced probing depths of the order of 10 nm and beyond. This not only facilitates direct access to the intrinsic bulk electronic structure of solids, but also allows extended depth profiling and the study of buried interfaces not possible by conventional photoemission. Here, we present two HAXPES case studies on transition metal hybrid and heterostructures demonstrating the potential of the method. We also discuss a new HAXPES setup at the high-brilliance hard x-ray synchrotron radiation source PETRA III at DESY (Hamburg) currently under construction.

Deformation of metallic glasses: Insight from in-situ high- energy x-ray diffraction

The most notable property of bulk metallic glasses is their ultrahigh (near theoretical) strength and hardness. Because many of known BMGs miss tensile plasticity and thus exhibit catastrophic failure upon tension it is of great importance to understand deformation mechanisms involved and thus improve their performance. Time-resolved in-situ x-ray diffraction experiments may nowadays be performed at high-brilliance synchrotron radiation sources for a variety of conditions. An example is provided, concerning mapping of the strain distribution in tensile stressed Zr-based BMG by in-situ hard x-ray diffraction.

New orbit correction method uniting global and local orbit corrections

A new orbit correction method, called the eigenvector method with constraints (EVC), is proposed and formulated to unite global and local orbit corrections for ring accelerators, especially synchrotron radiation(SR) sources. The EVC can exactly correct the beam positions at arbitrarily selected ring positions such as light source points, simultaneously reducing closed orbit distortion (COD) around the whole ring. Computer simulations clearly demonstrate these features of the EVC for both cases of the Super-SOR light source and the Advanced Light Source (ALS) that have typical structures of high-brilliance SR sources. In addition, the effects of errors in beam position monitor (BPM) reading and steering magnet setting on the orbit correction are analytically expressed and also compared with the computer simulations. Simulation results show that the EVC is very effective and useful for orbit correction and beam position stabilization in SR sources.

X-ray high-resolution diffraction using refractive lenses

Refractive x-ray lenses have recently been applied for imaging and scanning microscopy with hard x rays. We report the application of refractive lenses in an optical scheme for high-resolution x-ray diffraction, performed at a high brilliance synchrotron radiation source. An experimental proof of principle and a theoretical discussion are presented. In particular, we observe the x-ray diffraction pattern from a two-dimensional photonic crystal with 4.2μm periodicity, which normally is employed to scatter light in the infrared.

Application of synchrotron radiation techniques to nanoscience

The development of high-brilliance synchrotron radiation sources have provided powerful new methods for probing the structure and dynamics of nanostructured materials. We shall review some of the recent applications of synchrotron radiation techniques to the study of nanomaterials. These include both scattering and real-space imaging methods and the use of coherent X-ray beams for studying nanostructures, the use of resonant magnetic scattering to study magnetic nanostructures, and the use of photon correlation spectroscopy to study their dynamics.

Multilayer Fresnel zone plate for high-energy X-ray by DC sputtering deposition

A hard X-ray microbeam is a key technology for third-generation high-brilliance synchrotron radiation sources such as SPring-8. A Fresnel zone plate (FZP) is one of the promising focusing elements for X-rays. A multilayer (sputtered–sliced) FZP is suitable for use in hard X-ray region, because large thickness can be available. Zone (multilayer interface) roughness is inevitable to the multilayer FZP, which results in the inferior-focusing characteristic. Some Cu/Al concentric multilayers were fabricated by DC sputtering deposition. In order to reduce the oblique incidence of sputtered atoms on the wire substrate, a cylindrical slit was placed between the target and the wire substrate. As a result, the interface roughness was improved with very good repeatability.

Comparison of monochromators with a bent parabolic mirror and a varied-spacing grating for the 2.0 GeV high-brilliance synchrotron radiation source (VSX)

A design study of monochromators for a 2.0 GeV electron/positron storage ring for high-brilliance synchrotron radiation in the vacuum ultraviolet (VUV) and the soft X-ray regions is described. Two types of VUV/soft X-ray grazing-incidence monochromators, one with a bent parabolic mirror and the other with a varied-spacing grating, are designed. Without any slope error, the expected resolving power of the former is much higher, but the latter is less affected by slope errors of the optical elements.

Design of and metrological results from a bent parabolic mirror.

This article describes the successful design and fabrication of, and metrological results from, an elastically bent parabolic mirror. The mirror is equipped with a bending structure that allows the mirror to be bent meridionally to a parabolic shape. This bent parabolic mirror is the key component of the extremely high-quality monochromators designed for the SPring-8 figure-8 soft X-ray undulator and the 2.0 GeV high-brilliance synchrotron radiation source (VSX).

Insertion devices for BESSY II.

The high-brilliance synchrotron radiation source BESSY II will provide space for the installation of 14 insertion devices. At the time of writing (July 1997), eight insertion devices are funded. The first light for use by scientists will be available in January 1999. The undulators are designed for a scanning operation in parallel with the monochromator. This modus requires tight tolerances concerning the drive system. The first insertion device to be installed, a U-49 undulator, has been assembled and magnetically measured. The r.m.s. phase error is 2 degrees. An endpole configuration using coils with less than 64 amp-turns makes the angular kick smaller than +/-3 micro rad over a gap range 15-50 mm.

Synchrotron Radiation Diffraction Studies of Magnetic Materials

Since the advent of high brilliance synchrotron radiation sources, magnetic X-ray diffraction has become a standard microscopic probe for the investigation of magnetic structures, magnetic phase transitions and magnetic disorder phenomena. Modern experiments highlight the complementarity of this new probe to the standard neutron diffraction technique by taking advantage of the high momentum space resolution, the element sensitivity, the possibility to separate spinand orbital contributions etc. In this paper we present selected experiments performed at HASYLAB which exemplify the present possibilities of resonant and non-resonant magnetic X-ray diffraction.

Optics and beamlines for high-pressure research at the european synchrotron radiation facility

The European Synchrotron Radiation Facility (ESRF) is the first high-energy, high-brilliance synchrotron radiation source in operation today and it is ideally suited to high pressure research. Whit...

Surface/Interface X-Ray Diffraction

Abstract The structural challenges presented by the two-dimensional (2D) world of surfaces and interfaces have proven formidable. In spite of the critical role that they play in such diverse sciences as catalysis, tribology, metallurgy, and electronic devices and in spite of the expected richness of two-dimensional physics of melting, magnetism, and related phase transitions, only a few surface structures are known and most of those only semiquantitatively (e.g., their symmetry). Our inability in many cases to understand atomic structure and to make the structure/properties connection in the 2D region of surfaces and interfaces has significantly inhibited progress in understanding this rich area of science. Furthermore, the synthesis of new materials has played a key role in modern industrial evolution, and this synthesis is also the foundation of contemporary materials research. Many of the new materials fabrication processes are based on crystal growth and thin film deposition techniques, such as molecular beam epitaxy (MBE), chemical vapor deposition (CVD), liquid phase epitaxy (LPE), sputtering deposition, laser ablation and electrochemical plating. To improve the development and engineering of materials based on these techniques, it is essential to have a detailed understanding of the fundamental interactions and effects pertaining to the basic surface and interface structures. This knowledge will allow scientists and engineers to predict and control material properties based on the processing parameters and resulting configurations. This knowledge will be useful also for the understanding of modern composites, ceramics, and nanophase materials in which surfaces and interfaces play a large role in determining their physical and chemical characteristics. With the advent of high-brilliance synchrotron radiation sources and improved analytical methods, surface-sensitive X-ray techniques have recently been developed to study the structure and the associated reactions/transformations at surfaces and interfaces. These synchrotron X-ray techniques have already proven to be a powerful tool to probe surfaces/interfaces beyond the capabilities of earlier experimental methods involving electrons, ions, neutrons and light. This paper will discuss the general principles and experimental method of surface/interface X-ray diffraction as well as provide several examples to demonstrate the usefulness of the techniques applied to surface/interface problems.