Single crystal EXAFS at high pressure

Abstract

We present a new technique for structure characterization under high pressure conditions. The use of an undulator beam of the third-generation ESRF source of synchrotron radiation has enabled the first single crystal EXAFS experiments at high pressure using a diamond anvil cell as pressure generator. Taking advantage of the linear polarization of X-rays the technique becomes an orientation-selective probe of the local structure of materials. We describe the principle of the technique and some applications.     

A high aperture beamline for vacuum ultraviolet circular dichroism on the srs

The three-day international workshop Actinide-XAS-2006 was held at Forschungszentrum Karlsruhe (FZK), Germany, from September 18–20, 2006. Actinide-XAS-2006 was the fourth workshop on speciation, techniques, and facilities for radioactive materials at synchrotron light sources. The Actinide-XAS series addresses the specialized field of the application of synchrotron techniques for investigating radioactive materials and is a forum for teaching and scientific discussion in this field, thereby strengthening existing and establishing new transnational cooperative scientific networks. The first and second workshops, Actinide-XAS-1998 and Actinide-XAS-2000, were held in Grenoble at the ESRF. The third and last workshop, Actinide-XAS-2004, was held at Lawrence Berkeley National Laboratory.     

Current progress and future developments in sychrotron radiation instrumentation for high-pressure research including the esrf programme

Abstract

The field of synchrotron radiation instrumentation and techniques for high-pressure research is reviewed. Current state-of-the-art, recent developments, main directions of progress and areas with the greatest need for further developments are discussed. Large volume devices, diamond-anvil cells, temperature variation, detectors, all diffraction techniques and dispersive x-ray absorption are covered. Theplanned ESRF high-pressure facilities and programme are presented.     

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

Abstract

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. White-beam and monochromatic diffraction techniques are being optimized in particular for structural studies of low-Z materials and poor scatterers generally, the best example being hydrogen single crystals at very high pressures. Most high pressure measurements are carried out on a versatile beamline equipped with a wiggler and an undulator. Focusing and image plates are used in all monochromatic angle-dispersive studies. The success of the high pressure programme has so far been achieved on a non-optimized beamline, but the next phase of the programme needs an optimized facility. A beamline is being constructed to fully exploit the intrinsic qualities of this unique source and insertion devices for high pressure studies. Its main design concepts are presented.     

Diffraction study of actinides under pressure

Abstract

Uranium and thorium have sufficiently low radioactive dose rates to allow their study at synchrotrons and neutron facilities. Correspondingly, numerous compounds of these two actinides have been studied under pressure by synchrotron x-ray diffraction. The maximum pressures reached were on the order of 60-80 GPa, and 300 GPa in one case.

The situation is much more difficult for all other actinides. Their high level of radioactivity has up to now prevented their study at synchrotrons, except in a few special cases. In contrast, all actinide metals available in sufficient quantities, and a large number of compounds of highly radioactive actinides, have been studied in highpressure laboratory facilities.

Recent examples of in situ high pressure x-ray diffraction work will be described.     

Protein crystallography with the PILATUS 1M detector at the Swiss Light Source

The last few years have seen an increase in the demand of automation at synchrotron radiation facilities. The main driving forces behind this quest are the Structural Genomics Centers and related projects [1], with their need for large throughput of samples and an increasing number of relatively unskilled users with ever increasing demands.

In order to meet the needs of this diverse community, the structure determination process must be streamlined. A production pipeline for high volume determination of structures requires optimization and automation of current processes in use at synchrotron facilities. The ultimate goal is to arrive at a system that, with little more input than a sample, will provide the researcher with the final molecular structure.     

Meeting Reports: 2005 Annual Meeting of JSSRR (Japanese Society for Synchrotron Radiation Research)

The 18th Annual Meeting and General Assembly of the Japanese Society for Synchrotron Radiation Research (JSSRR) and the joint symposium of synchrotron radiation facility user's society groups were held at Sun-Messe Tosu Conference Hall in Tosu City, Japan, from January 7 to 9, 2005. The meeting was attended by 607 people and included 6 symposiums, 96 oral presentations, and 356 poster presentations covering all aspects of synchrotron radiation research and technology. The meeting also included 49 industrial exhibitions.

The six symposiums were on “Recent progress on soft X-ray optical elements,” “Now and the future on SR-XRF analysis for biological and environmental sciences,” “Recent development of THz Coherent Synchrotron Radiation,” “Super high-resolution protein structure analysis,” “Frontlines of Bio-Nano-microspectroscopy by UV-SX high brilliance SR,” and “The role of synchrotron radiation in the future of science: groundbreaking SR utilization for research on excited states”.     

Suppression of Jahn-Teller Distortion and Insulator-To-Metal Transition in LaMnO 3 at High Pressures

Structural, vibrational and electronic properties of LaMnO 3 under pressures up to 38 GPa have been studied by synchrotron X-ray powder diffraction, Raman spectroscopy, optical reflectivity, and transport measurements. The cooperative Jahn-Teller distortion of the MnO 6 octahedra of the perovskite-type structure is continuously suppressed with increasing pressure, a process which appears completed at ～20 GPa. The system remains insulating to 32 GPa, where an insulator-metal transition is observed. This transition is attributed to strengthened Mn--O--Mn interactions due to the increasing overlap of atomic orbitals.     

New techniques for new sources: A fresh look at energy-dispersive diffraction for high-pressure studies

Abstract

Energy-dispersive diffraction is the most frequently used technique for high-pressure studies with synchrotron radiation. For optimum performance it requires high-energy radiation and few existing sources are able to meet this requirement. This is also important with large volume devices which demand even higher energies in order to obtain sufficient transmission. When working with diamond-anvil cells, the main experimental difficulties arise from the very small sample sizes. The use of a conical diffraction geometry increases the diffracted intensities, improves the signal-to-noise ratio and largely overcomes the crystallite statistics problem. This technique can also be used to greatly simplify high-pressure single-crystal studies. Combining these developments with recent progress in detectors and electronics will open up the field of high-pressure kinetics, but it is only with the operation of third generation synchrotron sources such as the ESRF that the present experimental limitations will be overcome.

Presented at the IUCr Workshop on ‘Synchrotron Radiation Instrumentation for High Pressure Crystallography’. Daresbury Laboratory 20-21 July 1991     

Technical Reports: Time-Resolved Activities at the Advanced Photon Source Requiring the Pulsed Structure of the X-ray Beam

Scientific research in the time domain using the pulsed structure of the X-ray beams from a third-generation synchrotron source, such as the Advanced Photon Source (APS), has become a major interest among synchrotron users. The traditional material science, chemistry, and biology communities are getting an early glimpse of the potential impact of fast time-resolved X-ray studies. The scientific disciplines that have benefited from these studies include atomic and molecular physics, biology, chemical science, condensed matter physics, engineering science, environmental science, material science, and nuclear science. Technically, the turn-key-type femtosecond (fs) optical lasers with high peak power, used as pumps in many X-ray pump-probe experiments, have only recently become available.     

ESRF 11th users' meeting and workshops

More than 90 participants from Europe, the US and Japan gathered from April 27 to 29, 2005, in Zeuthen, near Berlin, to hold a lively international meeting on time-resolved soft X-ray science. The meeting continued the series of preceding workshops held in 2002 in Napa (California, USA) and in 2003 in Montreux (Switzerland). It was organized by the three synchrotron radiation sources BESSY (Berlin, Germany), the Swiss Light Source SLS (Villigen) and the French synchrotron radiation source SOLEIL (Orsay).

The aim of the workshop was to bring together the existing ultrafast laser community and the emerging ultrafast X-ray community in order to discuss recent scientific highlights from both fields and to outline new directions for the application of ultrafast X-rays.     

Nuclear resonance scattering

Nuclear resonance scattering is an atomistic spectroscopy sensitive to magnetic and electronic properties as well as slow and fast structural dynamics. Applications, which take advantage of both the outstanding properties of third generation synchrotron radiation sources and those of the Mössbauer effect, benefit most. Examples resulting from investigations at the ESRF will be given in applications to high pressure and low temperatures, nano-scale materials, and dynamics of disordered systems. To cite this article: R. Rüffer, C. R. Physique 9 (2008).     

Ksrs inaugurated in moscow

To foster scientific collaborations among the Advanced Photon Source (APS), the European Synchrotron Radiation Facility (ESRF), and the Super Photon Ring-8 GeV (SPring-8), the three facilities meet on a regular basis to hold technical discussions on accelerator and beamline topics and management and operational issues of common interest. The 2008 Three-Way Meeting (3WM) was held on March 18–19 at the APS with more than 20 representatives from each facility. Satellite workshops were also held on the topics of X-ray Optics, Nanoscience with X-rays, User Services, and Accelerator R&;D. The 3WM and satellite workshops served as platforms for presentations and discussions of new and exciting developments at the three synchrotron sources.     

From Atoms to Aerosols: A Workshop on Opportunities for Chemical Physics at the ALS

Can the capabilities of the “big three” synchrotron radiation facilities still be “big” in the future? The three third-generation synchrotron radiation facilities — ESRF, APS, and SPring-8 — were inaugurated with performances significantly beyond that of smaller, lower-energy machines. For the past few years, though, mid-scale (～3 GeV) low-emittance machines, both operating and planned, have been gaining ground, in part taking advantage of the technological developments at the larger rings. The future competitiveness of the big three was one of the issues addressed during the ESRF/APS/SPring-8 Three-Way Meeting.     

Probing the local,electronic and magnetic structure of matter under extreme conditions of temperature and pressure

ABSTRACT

In this paper we present recent achievements in the field of investigation of the local, electronic and magnetic structure of the matter under extreme conditions of pressure and temperature. These results were obtained thanks to the coupling of a compact laser heating system to the energy-dispersive XAS technique available on the ID24 beamline at the ESRF synchrotron. The examples chosen concern the melting and the liquid structure of 3d metals and alloys under high pressures (HPs) and the observation of temperature-induced spin crossover in FeCO₃ at HP.     

XRMS 2008 Workshop at DESY

From January 23–24, 2008, the Deutsches Elektronen Synchrotron (DESY) provided a forum for more than 75 scientists from 12 countries to discuss recent developments in the investigation of magnetic solids with synchrotron radiation. The framework for this meeting was the International Workshop for X-ray Spectroscopy of Magnetic Solids (XRMS 2008). The XRMS workshop series was established in 2000 when the first meeting was held at BESSY (Berlin, Germany). It then continued annually or bi-annually, always in conjunction with a users meeting at one of the European synchrotron radiation facilities. In this year, the XRMS workshop preceded the HASYLAB Users Meeting at DESY on January 25.     

Laser shock XAFS studies at OMEGA facility

ABSTRACT

State-of-the-art laser facilities offer an excellent opportunity for studying materials at Mbar-Gbar pressures by dynamical compression. This paper summarizes recent experiments on EXAFS measurements of compressed solid iron up to 5?Mbar using OMEGA laser facility. The X-ray source is produced by a spherical implosion, providing enough brightness and spectral smoothness required for EXAFS measurements. The compression path is tuned by laser pulse shaping to achieve off-hugoniot states. With an anharmonic model, the density, temperature and upper limit of strength of the compressed iron are determined from EXAFS data. Prospects of XAFS study of other materials are also discussed.     

Equations of state of MgO at high pressure and temperature

Abstract

A synchrotron X-ray diffraction study on MgO has been done at simultaneous high pressure and temperature. The lattice parameter of MgO has been measured up to a static pressure of 6 GPa and a temperature of 1273 K, using a large volume pressure cell and energy-dispersive synchrotron X-ray powder diffraction. The compression was made following six high-temperature isotherms. A Vinet equation of state was used to fit the experimental P-V-T data. The Vinet's model compares very well with the experimental data above the Debye temperature (760 K) and allows the use of MgO as an alternative internal pressure calibrant for experiments at high temperature.     

2011 U.S. National School on Neutron and X-ray Scattering

The 13^th annual U.S. National School on Neutron and X-ray Scattering was held June 11-25, 2011, at both Oak Ridge and Argonne National Laboratories. This school brought together 65 early career graduate students from 56 different universities in the United States and provided them with a broad introduction to the properties and techniques available at the major large-scale neutron and synchrotron X-ray facilities. This school is focused primarily on techniques relevant to the physical sciences, but also touches on cross-disciplinary bio-related scattering measurements. During the school, the students received lectures by more than 30 researchers from academia, industry, and national laboratories and participated in a number of short demonstration experiments at Argonne's Advanced Photon Source (APS) and Oak Ridge's Spallation Neutron Source (SNS) and High Flux Isotope Reactor (HFIR) facilities to get hands-on experience in using neutron and synchrotron sources.     

Determination of Phonon Dispersion Curves at Gigapascal Pressures by Inelastic X-ray Scattering

The study of phonon dispersion curves of materials under hydrostatic pressure provides important information such as the evolution of sound velocities, elastic constants, interatomic potentials, phase transition mechanisms, etc. Until very recently, coherent inelastic neutron scattering was the only spectroscopic technique, which allowed performing these types of studies up to typically 10 GPa. Today, inelastic X-ray scattering with meV energy resolution provides a complementary spectroscopic technique, where, using diamond anvil cell techniques, pressures beyond 100 GPa can be reached.