Ultrafast X-ray science at the advanced light source

On May 19, 2004, 250 guests from all over the world joined the DESY research center to celebrate 40 years of research with synchrotron radiation at DESY in Hamburg. “The first measurements with the light beam from the DESY ring accelerator started in 1964. DESY was one of the seed laboratories in which the worldwide success story of research with synchrotron radiation began,” Albrecht Wagner, chairman of the DESY Board of Directors, explained in his welcoming address. “Today, more than 1,900 scientists from 31 countries come to DESY every year to carry out experiments with synchrotron radiation.”

Forty years ago, synchrotron radiation at DESY started from scratch. At the beginning of the 1960s, the radiation generated by the electrons in the bending magnets of their new 6 GeV electron synchrotron was regarded by DESY particle physicists as an unwanted, disruptive effect.     

High-pressure Mössbauer spectroscopy with nuclear forward scattering of synchrotron radiation

Abstract

Using a diamond anvil cell, high-pressure ⁵⁷Fe Mössbauer spectroscopy has been performed with the nuclear forward scattering of synchrotron radiation. A pressure-induced magnetic hyperfine interaction at ⁵⁷Fe in SrFeO_{2, 97} has been detected at 44 GPa and 300 K for a first time by a quantum-beat modulation of the decay rate after collective nuclear excitation by the synchrotron pulse. The basic concept and method used to detect nuclear forward scattering with synchrotron radiation are discussed.     

X-ray absorption spectroscopy and high pressure

Abstract

The difficulties of the adaptation of high pressure to x-ray absorption are presented. The advantages of the energy-dispersive geometry are discussed as well as the future improvements expected with the new synchrotron radiation sources.

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

A large volume pressure cell for high temperatures

Abstract

Studies of matter under very high pressure at synchrotron radiation sources are mostly done using pressure cells with single-crystal diamond anvils. In some cases the available volume (≤ 10^?3mm³)in such cells causes problems especially at high temperature and for crystal synthesis. To ensure sufficient homogeneity of pressure and temperature, the use of cells with large sample volumes (≥ 1 mm³) is necessary.

Existing devices for such measurements are compared with a novel setup which consists of a toroidal anvil arrangement and a lightweight (50 kg) press with 250 tonnes (2.5 MN) capacity. Preliminary tests of this instrument with synchrotron radiation are reported.

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

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”.     

Nuclear resonant scattering of synchrotron radiation by multilayer structures

Multilayer structures form a particular class of samples employed in nuclear resonant scattering of synchrotron radiation. Their specific properties lead to unusual energy and time characteristics of nuclear resonant scattering, which differ much from those of single crystals. The analysis of these distinctions is presented. Several approaches to achieve pure nuclear reflections with multilayers are discussed. Finally, we review the studies of multilayer structures with nuclear resonant scattering of synchrotron radiation.

     

Polarization effects in resonant nuclear scattering

Polarization phenomena are present in every radiative transition, whether it is of atomic or nuclear origin. Nuclear resonant scattering of synchrotron radiation is an ideal technique for their study because (a) the probing radiation is in a well characterized polarization state, in most cases linear, (b) the scattered radiation can be efficiently analyzed with polarization filters, and (c) synchrotron pulses are very short compared to the lifetime of a nuclear resonance, resulting in a clean signal. In the following article we describe experimental and theoretical studies of the 14.4 keV Mössbauer resonance of ⁵⁷Fe and its transitions with linear and circular polarization. After introducing the required instrumentation a formalism to calculate time dependent polarization phenomena is derived. With the help of different scattering geometries we illustrate various aspects, such as polarization mixing and selective excitation of subsets of the resonance. Perhaps the most fascinating example is the Faraday geometry where the E-vector rotates several 360^ο turns during the lifetime of the resonant scattering. A comparison of this phenomenon with the optical Faraday effect is given. New powerful synchrotron radiation sources will enable researchers to exploit polarization phenomena in nuclear resonant scattering to detect subtle changes in physically and chemically relevant systems.

     

Application of Advanced Synchrotron Radiation–Based and Conventional Molecular Techniques in Recent Research on Molecular Structure,Metabolic Characteristics,and Nutrition in Coproducts from Biofuel Processing

Abstract

Advanced synchrotron radiation infrared microspectroscopy, as a nondestructive and rapid analytical technique, is able to simultaneously reveal the structural, chemical, and environmental features of biomaterials at cellular and molecular levels within intact tissue. However, to date, this advanced synchrotron-based technique is still seldom used by feed and nutrition scientists. This article aims to provide detailed information regarding how to apply advanced synchrotron radiation–based and conventional molecular techniques to research in coproducts from biofuel processing on the molecular structure, metabolic characteristics, and nutrition. The information described in this article provides better insight on coproduct research progress and updates with advanced synchrotron radiation-based and globar-based (conventional) molecular spectroscopy.     

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.     

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.     

Diffusion in crystalline materials

Recently nuclear scattering of synchrotron radiation proved to be a powerful new method to study the elementary diffusion jump in crystalline solids. The scattered radiation decays faster when atoms move on the time scale of the excited-state lifetime of a Mössbauer isotope because of a loss of coherence. The acceleration of the decay rate differs for different crystal orientations relative to the beam providing information not only about the rates but also about the directions of the elementary jumps. We discuss first applications of the method.

     

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     

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.     

General properties of nuclear resonant scattering

The process of nuclear resonant scattering resonant scattering is considered on the basis of an optical model. The coherent properties coherent properties of the radiation and scattering mechanism are described. The complementary pictures of γ-ray resonant scattering in energy and time domains are presented. Special attention is paid to scattering of a γ quantum by an ensemble of nuclei. The central concept of the theory of nuclear resonant scattering, the nuclear exciton, nuclear exciton as a delocalized nuclear excitation, is described in detail. It is shown that both temporal and spatial aspects of coherence play a crucial role in the evolution of the nuclear exciton. A large place is given to the analysis of resonant scattering of synchrotron radiation by nuclear ensembles.

     

The X-ray emission from the knots in 3C 120

3C 120 is a Seyfert galaxy with a well detected X-ray jet. We investigate the X-ray emission of its five jet knots and fit their spectral energy distributions (SEDs) from the radio to the X-ray bands with a single-zone lepton model. We find that the SEDs of knots k7, s2, and s3 can be explained by synchrotron radiation, and the X-rays are the simple extension of the radio-optical emission component, but that of the inner knot k4 requires the IC/CMB model, in which the X-rays are due to the inverse Compton scattering of the cosmic microwave background photons by relativistic electrons in the jet with a beaming factor δ∼14. The outer knot k25 is resolved into a three-part sub-structure. It is shown that the fitting of the X-rays from this knot with the IC/CMB model needs an extraordinary beaming factor δ∼15–25 for a jet at the kpc scale. If the X-rays of knot k25 are produced by synchrotron radiation similar to k7, s2, and s3, they may be contributed by a relativistic electron population whose radiations in other wavelengths are not detected.

     

Third annual ALS users’ meeting

The 20^th anniversary of Synchrotron Radiation News is a good opportunity to think back about the extraordinary development of the field during that period. From personal experience I can offer comments in two areas: ? the evolution of synchrotron radiation research facilities from the 1970s to the 1990s;

? the early history and impact of wiggler and undulator insertion devices.

     

Enhancement and speedup in nuclear resonant diffraction

The interaction of Mössbauer radiation with the nuclei in a single crystal provides the unique possibility to enhance the coherent channel in nuclear resonance scattering by means of a properly phased excitation of the scattering centers. When a primary beam is incident in the exact Bragg direction, all nuclei are excited in phase. The resonance parameters of such a collective nuclear excitation of a perfect single crystal (γ-exciton) are entirely different from those of an individual nuclear excitation. In Bragg geometry diffraction, the resonance lines are shifted and broadened (enhancement effect), the lifetime of the collective excited state is shortened (speedup effect) and the reflectivity becomes total (suppression effect). Recent experiments arc reviewed, where these effects were studied in the resonant diffraction of Mössbauer and of synchrotron radiation.

     

Dielectric loss measurements on silver halide sheet crystals

Abstract

A series of studies on the partial X-ray diffuse scattering intensities from ternary alloys analysed through synchrotron radiation experiments has been reviewed. An intensity expression for the short-range order diffuse scattering has been developed, which is necessary in understanding the separation method of an observed X-ray diffuse intensity into partial intensities contributed from different origins. Techniques have been described in detail mainly concerning the Cu₂NiZn alloy, which have shown the benefits of the anomalous scattering effect of synchrotron radiation. The negative partial intensity maximum for the Cu-Ni pair found in the Cu-Ni-Zn alloy has been discussed from the viewpoints of crystallography and thermodynamics. In addition, at the end of the paper, local atomic arrangements causing the diffuse scatterings have been discussed.     

Energy - dispersive X - ray diffraction of the ammonium - halides under pressure

Abstract

The structure of the ammonium halides NH₄X (X = Cl, Br, I) has been studied under pressure up to 40 GPa by energy dispersive X-ray diffraction using synchrotron radiation. Equations of state and a discussion on the possible structure of phase V will be presented.     

Rietveld analysis for energy dispersive x-ray diffraction under high pressure with synchrotron radiation

Abstract

A new program has been developed for the conversion of energy-dispersive x-ray diffraction spectra obtained from powder samples at high pressure in a diamond anvil cell (DAC) into conventional pseudo angle-dispersive data. The program is compatible with a conventional Rietveld program. This allows the determination of the structural parameters of the samples investigated. Results of a synchrotron radiation study of polycrystalline SrFCl in the tetragonal phase at high pressure are presented.

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