Christoph Quitmann

Diffraction-limited storage rings - a window to the science of tomorrow.

This article summarizes the contributions in this special issue on Diffraction-Limited Storage Rings. It analyses the progress in accelerator technology enabling a significant increase in brightness and coherent fraction of the X-ray light provided by storage rings. With MAX IV and Sirius there are two facilities under construction that already exploit these advantages. Several other projects are in the design stage and these will probably enhance the performance further. To translate the progress in light source quality into new science requires similar progress in aspects such as optics, beamline technology, detectors and data analysis. The quality of new science will be limited by the weakest component in this value chain. Breakthroughs can be expected in high-resolution imaging, microscopy and spectroscopy. These techniques are relevant for many fields of science; for example, for the fundamental understanding of the properties of correlated electron materials, the development and characterization of materials for data and energy storage, environmental applications and bio-medicine.

X-Treme beamline at SLS: X-ray magnetic circular and linear dichroism at high field and low temperature

X-Treme is a soft X-ray beamline recently built in the Swiss Light Source at the Paul Scherrer Institut in collaboration with École Polytechnique Fédérale de Lausanne. The beamline is dedicated to polarization-dependent X-ray absorption spectroscopy at high magnetic fields and low temperature. The source is an elliptically polarizing undulator. The end-station has a superconducting 7 T-2 T vector magnet, with sample temperature down to 2 K and is equipped with an in situ sample preparation system for surface science. The beamline commissioning measurements, which show a resolving power of 8000 and a maximum flux at the sample of 4.7 × 10(12) photons s(-1), are presented. Scientific examples showing X-ray magnetic circular and X-ray magnetic linear dichroism measurements are also presented.

Nanostructure characterization by a combined x-ray absorption/scanning force microscopy system

A combined x-ray transmission and scanning force microscope setup (NanoXAS) recently installed at a dedicated beamline of the Swiss Light Source combines complementary experimental techniques to access chemical and physical sample properties with nanometer scale resolution. While scanning force microscopy probes physical properties such as sample topography, local mechanical properties, adhesion, electric and magnetic properties on lateral scales even down to atomic resolution, scanning transmission x-ray microscopy offers direct access to the local chemical composition, electronic structure and magnetization. Here we present three studies which underline the advantages of complementary access to nanoscale properties in prototype thin film samples.

9th International Conference on X-Ray Microscopy

This volume compiles the contributions to the International Conference on X-Ray Microscopy (XRM2008) held on 20–25 July 2008 in Zurich, Switzerland. The conference was the ninth in a series which started in Gottingen in 1984. Over the years the XRM conference series has served as a forum bringing together all relevant players working on the development of methods, building instrumentation, and applying x-ray microscopy to challenging issues in materials science, condensed matter research, environmental science and biology. XRM2008 was attended by about 300 participants who followed 44 oral presentations and presented 220 posters. Figure 1: Participants of the XRM2008 conference gathered in front of the main building of the ETH-Zurich. The conference showed that x-ray microscopy has become a mature field resting on three pillars. The first are workhorse instruments available even to non-specialist users. These exist at synchrotron sources world-wide as well as in laboratories. They allow the application of established microscopy methods to solve scientific projects in areas as diverse as soil science, the investigation of cometary dust particles, magnetic materials, and the analysis of ancient parchments. Examples of all of these projects can be found in this volume. These instruments have become so well understood that now they are also commercially available. The second pillar is the continued development of methods. Methods like stroboscopic imaging, wet cells or high and low temperature environments add versatility to the experiments. Methods like phase retrieval and ptychographic imaging allow the retrieval of information which hitero was thought to be inaccessible. The third pillar is the extension of such instruments and methods to new photon sources. With x-ray free electron lasers on the horizon the XRM community is working to transfer their know-how to these novel sources which will offer unprecedented brightness and time structure, but which at the same time require unprecedented effort to perform the experiment and to extract meaningful information from the data. Resting on these three pillars, the XRM community seems well prepared to solve the scientific questions of today and to help solve even more challenging scientific questions in the future. Many people contributed to the success of XRM2008, first and foremost were the participants with their excellent contributions and through their lively discussions. Organizing the event was made possible due to many helping hands and brains at the organizing institution, the Paul Scherrer Institut. It is our pleasure to thank all of these people. Financial support was given by the Gold Sponsor, XRADIA, by the European Round Table for Synchrotrons and Free Electron Lasers, the Center for Imaging Science and Technology at Zurich, and by the Swiss National Science Foundation. The conference was kindly hosted by ETH Zurich which provided a perfect setting for this venue. We thank all the participants of XRM2008, everybody who helped in the organization and all financial supporters and are looking forward to hearing about further progress during XRM2010 which will be organized by Argonne National Laboratory in Chicago. C Quitmann, C David, F Nolting, F Pfeiffer and M Stampanoni Proceedings Editors Figure 2 View over Zurich and into the alps from the terrace of the ETHZ main building during the XRM2008 reception. Figure 3 Flag tosser and Alphorn blowers in front of the ETH Zurich main building during the XRM2008 opening reception. Figure 4 Industry exhibition in the entrance hall of the ETHZ main building. Figure 5 Lively discussions amongst the conference participants took place during the two poster sessions. Figure 6 Lecture hall with the participants busily discussing between talks. Figure 7 Past and present winners of the Werner Meyer-Ilse Award are joined by Andrea Meyer-Ilse, the wife of the deceased x-ray microscopy pioneer Werner Meyer-Ilse. From left to right: Weilun Chao (winner 2005), Ann Sakdinawat (winner 2008), Piere Thibault (winner 2008), Andrea Meyer-Ilse and M Feser (winner 2002). Figure 8 Reception in the court of Schloss Rapperswil during the XRM2008 conference excursion. Figure 9 Conference participants walking towards the castle of Rapperswil during the conference excursion. Figure 10 Accompanying persons group gathered in the port of Lucerne.

NanoXAS, a novel concept for high resolution microscopy

We currently develop a novel type of scanning x-ray microscope. This instrument will combine the chemical specificity of x-ray absorption spectroscopy with the very high spatial resolution of scanning probe microscopy . In a fundamentally new instrumental approach, the instrument can be used as a conventional scanning transmission x-ray microscope (STXM), as a conventional scanning probe microscope (SPM) or in a mode combining these two techniques. In the latter case, the sample is placed in the focus generated by the fresnel zone plate of the STXM. The SPM-tip placed downstream acts as as a local detector of the emitted photoelectrons. Simulations and experiments have shown that the use of shielded SPM-tips is crucial to obtain a strongly increased chemical resolution. In contrast to similar projects underway at other synchrotrons we use a coaxial geometry. This should greatly enhance the flux density and reduce background signals caused by straylight illuminating the tip.

Extended SX-700 type monochromator combining normal and grazing incidence optics for a new undulator beamline at SLS

Abstract The surfaces and interfaces spectroscopy (SIS) beamline at the Swiss Light Source (SLS) covers the photon energy range from 10 to 800 eV . The beamline will start operation in summer 2001. The optical design is based on a SX-700 type plane grating monochromator extended by a normal incidence light path to provide high resolving power and harmonic rejection also at low photon energies.

Surface science at the PEARL beamline of the Swiss Light Source

The Photo-Emission and Atomic Resolution Laboratory is a new soft X-ray beamline at the Swiss Light Source for the study of surface structure using photoelectron diffraction and scanning tunneling microscopy.

Photon Counting System for Time-resolved Experiments in Multibunch Mode

Photon Counting System for Time-resolved Experiments in Multibunch Mode Aleksandar Puzic a; Timo Korhonen a; Babak Kalantari a; Jörg Raabe a; Christoph Quitmann a; Patrick Jüllig b; Lars Bommer b; Dagmar Goll b; Gisela Schütz b; Sebastian Wintz c; Thomas Strache c; Michael Körner c; Daniel Markó c; Chris Bunce c;Jürgen Fassbender c a Paul Scherrer Institut, Villigen, Switzerland b Max-Planck-Institut fŸr Metallforschung, Stuttgart, Germany c Forschungszentrum Dresden-Rossendorf, Dresden, Germany

A single probe for imaging photons, electrons and physical forces.

The combination of complementary measurement techniques has become a frequent approach to improve scientific knowledge. Pairing of the high lateral resolution scanning force microscopy (SFM) with the spectroscopic information accessible through scanning transmission soft x-ray microscopy (STXM) permits assessing physical and chemical material properties with high spatial resolution. We present progress from the NanoXAS instrument towards using an SFM probe as an x-ray detector for STXM measurements. Just by the variation of one parameter, the SFM probe can be utilised to detect either sample photo-emitted electrons or transmitted photons. This allows the use of a single probe to detect electrons, photons and physical forces of interest. We also show recent progress and demonstrate the current limitations of using a high aspect ratio coaxial SFM probe to detect photo-emitted electrons with very high lateral resolution. Novel probe designs are proposed to further progress in using an SFM probe as a STXM detector.

Lattice and Magnetic Dynamics of a Laser Induced Phase Transition in FeRh

We study the two coupled components of the laser induced phase transition in FeRh. We compare structural and magnetization dynamics measured with respectively time-resolved x-ray diffraction and magneto optical Kerr effect.