Scientific Highlights

MOOCs – a paradigm shift in education

In March 2018, the nine-week MOOC “Introduction to synchrotrons and x-ray free-electron lasers” (abbreviated to “SYNCHROTRONx”) came online via the edX provider of the École Polytechnique Fédérale de Lausanne (EPFL), created by Phil Willmott of the Swiss Light Source, Paul Scherrer Institute. “MOOC” is an acronym for “massive open online course”, a teaching platform started in the first decade of this century, which has become increasingly popular in the last five to six years. MOOCs have no limits to participation and are free. Some of the most popular MOOCs can attract many tens of thousands of participants. Even the most specialized subjects may have an initial enrollment of over a thousand, more than an order of magnitude larger than that typically found in traditional higher education. There were over 70 million MOOC enrollments covering nearly 10’000 subjects offered by the top five providers in 2017 alone!

Creation and deletion of isolated magnetic skyrmions via electrical currents

The writing and deletion of magnetic Skyrmions is a fundamental step towards the fabrication of memory devices based on this promising spin configuration. Researchers at the Korea Institute of Technology have demonstrated the writing and deleting of isolated magnetic Skyrmions at room temperature in ferrimagnetic multilayer superlattice stacks using electrical currents.

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Fresnel Zone Plates with Zone Widths below 10 nm

The spot size of a Fresnel Zone Plate lens is mainly determined by the zone widths of its outermost zone. It is therefore essential to fabricate zone plates with structures as small as possible for high-resolution X-ray microscopy. Researchers at the Laboratory for Micro- and Nanotechnology at the PSI have now developed Fresnel zone plates with zone widths well below 10 nm, down to 6.4 nm. These lenses are capable of pushing resolution in X-ray microscopy to the single-digit regime.

Dr. Caterina Biscari, Director of the ALBA Synchrotron in Spain and Vice Chair of LEAPS, League of European Accelerator-based Photon Sources, presented the LEAPS Strategy 2030 to Jean-David Malo, Director, Directorate General Research and Innovation, European Commission

LEAPS join forces with the European Commission to strengthen Europe’s leading role in science

“A world where European science is a catalyst for solving global challenges, a key driver for competitiveness and a compelling force for closer integration and peace through scientific collaboration.” This is the vision of LEAPS, League of European Accelerator-based Photon Sources, on which the LEAPS Strategy 2030 is based. Director Jean-David Malo, DG Research and Innovation, received the strategy today at the Bulgarian Presidency Flagship Conference on Research Infrastructures.

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HERCULES at the Swiss Light Source

In the week of March 18-23 PSI welcomes 20 PhD students and postdocs taking part in the HERCULES 2018 school on Neutron and Synchrotron Radiation. They will attend lectures and perform two days of practical courses at several beam lines of the Swiss Light Source.

Left: X-ray absorption spectra from supersaturated calcium carbonate solutions taken with a liquid microjet at the PHOENIX beamline. Comparison of the spectra with theoretical modeling shows the dominance of various ion pairs in solution, as expected in a classical solution. Right: image of liquid microjet in PHOENIX endstation.

Are supersaturated calcium carbonate solutions classical or non-classical ?

Classical theory predicts that supersaturated carbonate solutions consist mostly of ions and ion pairs, with a small number of larger clusters present in the solution. The population of the different sized clusters in a solution is solely defined by the cluster’s size dependent Free Energy. If clusters are large enough they serve as nucleation germs for a new solid phase. The nucleation occurs once the surface free energy barrier posed by the new solid-liquid interface is overcome by the free energy win from bulk phase growth.

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Unravelling structure sensitivity in CO2 hydrogenation over nickel

Using a unique set of well-defined silica-supported Ni nanoclusters (1–7 nm) and advanced characterization methods it was proved how structure sensitivity influences the mechanism of catalytic CO2 reduction, the nature of which has been long debated.

First Pilot Experiment at SwissFEL-Alvra: UV photo-induced charge transfer in OLED system

On the 17th of December 2017 SwissFEL saw its first pilot experiment in the Alvra experimental station of the SwissFEL ARAMIS beamline.

First time resolved Pilot Experiment by SwissFEL: Semiconductor to metal transition in Ti3O5 nanocrystals

On the 30th of November 2017 SwissFEL saw its first time resolved pilot experiment in the Bernina experimental station of the SwissFEL ARAMIS beamline. A team of scientists from the University of Rennes, ESRF and PSI, led by Marco Cammarata (Univ. Rennes) and Henrik Lemke (PSI), successfully started the experimental phase at SwissFEL.

Extreme Ultraviolet Vortices at Free Electron Lasers

PSI scientists have developed tailored diffractive X-ray optics for a free electron laser that induces an optical vortex in extreme ultraviolet radiation. The experiment facilitates the first demonstration of orbital angular momentum in radiation created by a free electron laser in the extreme ultraviolet regime, with an extraordinary clean and defined wavefront. In a collaborative effort with researchers from the FERMI free electron laser in Trieste, Italy and from the University of Nova Gorica in Slovenia, the wavefront of the intense beams carrying an orbtial angular momentum was characterized. Furthermore, a method to characterize the footprint of a focused beam from a free electron laser was refined based on ablation imprints in polymers and subsequent treatment with organic solvents. In this way, the sensitivity of the imprint method could be enhanced to a dynamic range of three orders of magnitude in a single shot.

How ‘super-microscopes’ are changing the face of European science

13 November 2017 – Brussels – 16 organisations representing 19 light sources facilities across Europe gathered to launch the LEAPS initiative and signed an agreement to strengthen their collaboration, in the presence of Robert-Jan Smits, Director General for Research and Innovation (RTD) at the European Commission, and Giorgio Rossi, Chair of the European Strategy Forum on Research Infrastructures (ESFRI).

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Magnetic structures take a new turn

The unexpected finding that in an ‘artificial spin ice’ magnetostatic energy can be transformed into directed rotation of magnetization provides fresh insights into such nano-patterned magnetic structures — and might enable novel applications in nanoscale devices.

First light in SwissFEL Experimental Station Bernina

Friday, October 20th, 2017, we brought the first light (wavelength 1.2 nm) into the experimental hutch of Bernina. The beam passed the Alvra endstation, went through the diagnostic devices and hit the diagnostic screen in front of the refocussing KB-system of Bernina. The upper picture shows the pink beam on the last diagnostic screen of the beamline. The lower left at the entrance of Bernina-hutch, 133 m downstream of the undulator. The lower right picture shows the beam centered in the alignment iris in front of the KB-system.

Making the world go round - a look into the structure of a prominent heterogeneous catalyst

Fluid catalytic cracking catalysts, which are composite particles of hierarchical porosity, were examined using ptychographic X-ray tomography. These particles are essential to the conversion of crude oil into gasoline. Examination of catalysts at decreasing levels of catalytic conversion efficacy allowed the detection of possible deactivation causes.

Magnetisation switching of a 500 nm diameter Pt/Co/AlOx disc.

Time- and spatially-resolved magnetization dynamics driven by spin-orbit torques

Current-induced spin-orbit torques hold a great potential for manipulation of magnetization at ultrafast timescales. Researchers at ETH Zürich have demonstrated, using time-resolved STXM imaging at the Swiss Light Source, the influence of spin-orbit torques on the switching behaviour of Pt/Co/AlOx nanostructured elements.

Schematic illustration of lateral homo-epitaxial growth in which well-ordered zone-cast material provides a template for further deposited molecules.

Highly Crystalline C8-BTBT Thin-Film Transistors by Lateral Homo-Epitaxial Growth on Printed Templates

Highly crystalline thin films of organic semiconductors offer great potential for high-performance, low-cost flexible electronics. Researchers at IMEC Belgium have developed a new double-step thin film fabrication process that offers higher performance devices. Soft X-ray spectro-microscopy at the Swiss Light Source was used to prove that the increased performance comes from larger areas of material sharing the same molecular orientation.

ATHOS Conceptual Design Report (CDR)

The ATHOS Conceptual Design Report has recently been completed and describes the ATHOS project in detail. The CDR starts with a summary of the characteristics of the ATHOS undulator line. Especially the design parameters of the different ATHOS operation modes are explained and illustrated by simulation results. The core part of the report is a description of all key components, i.e. from the electron bunch extraction kicker down to the ATHOS experimental stations.

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Dr. Nan Xu awarded SPS 2017 Prize in Condensed Matter Physics

The SPS 2017 Prize in Condensed Matter Physics, sponsored by IBM, has been awarded to Dr. Nan Xu for his excellent work on topological quantum states. Dr. Nan Xu is a joint postdoc of Paul Scherrer Institute (PSI) and the École Polytechnique Fédérale de Lausanne (EPFL).

A new RIXS analyzer scheme based on transmission zone plates

PSI scientists have developed a new type of X-ray optics that allows for analyzing the emission in resonant inelastic x-ray scattering (RIXS) experiments. The new approach combines the energy dispersion with imaging capabilities. In a collaborative effort with research groups from Göttingen and Hamburg, two new classes of RIXS experiments, energy mapping and RIXS imaging, have been demonstrated.

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Single-shot Monitoring of Ultrafast Processes via X-ray Streaking at a Free Electron Laser

The advent of x-ray free electron lasers has extended the unique capabilities of resonant x-ray spectroscopy techniques to ultrafast time scales. Here, in collaboration between researchers from PSI, Sorbonne Universités, HASYLAB/DESY, Synchrotron SOLEIL, CNRS, and Uppsala University, we report on a novel experimental method that allows retrieving with a single x-ray pulse the time evolution of an ultrafast process, not only at a few discrete time delays, but continuously over an extended time window.

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Nanomaterial helps store solar energy: efficiently and inexpensively

By combining a scalable cutting-edge synthesis method with time-resolved X-ray absorption spectroscopy measurements, it was possible to capture the dynamic local electronic and geometric structure during realistic operando conditions for highly active OER perovskite nanocatalysts.

Understanding the reaction mechanism in lignin catalytic fast pyrolysis

Lignin is a major constituent of plants, and may be used as a precursor for fuels and fine chemicals. Catalytic fast pyrolysis of lignin is one of the most promising approaches. By using vacuum ultraviolet synchrotron radiation and threshold photoelectron spectroscopy we could identify elusive intermediates, which are responsible for the formation of phenol and benzene and could thus tackle this reaction mechanism. Mechanistic understanding could enable targeted improvement of production methods in the future, beyond the currently used "cook-and-look" approach.

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Scientists get first direct look at how electrons ‘dance’ with vibrating atoms

Scientists at the SLAC National Accelerator Laboratory and Stanford University - one of the leading authors, Simon Gerber, has in the meantime relocated to PSI - have made the first direct measurements, and by far the most precise ones, of how electrons move in sync with atomic vibrations rippling through an quantum material, in the present study an unconventional superconductor, as if they were “dancing" to the same beat.

Photonic structure of white beetle wing scales: optimized by evolution

A very thin layer on this beetle’s wings exhibits a complicated structure on the nanoscale that gives them a bright white color. X-ray nanotomography acquired at the Swiss Light Source provides a faithful image of this structure in three dimensions with which scientists can confirm its evolutionary optimization: just enough material for an efficient reflection of white light.

Isomer-Selective Generation and Spectroscopic Characterization of Biofuel Intermediates

Online combustion analysis relies heavily on spectral data to detect reactive intermediates isomer-selectively to establish e.g. kinetic flame models. Due to the difficulty to generate these species cleanly, spectral data are rather scarce. Here we report on the selective generation of three picolyl radical isomers (C5H4N-CH2*) by deamination of aminomethylpyridines. Picolyl radicals are relevant in biofuel combustion, and could now be characterized by threshold photoelectron spectroscopy using synchrotron radiation. Vibrationally resolved bands and distinct ionization energies allow for isomer-specific detection of these elusive species in complex environments and permit us to explore new avenues in soot- and NOx formation kinetics.

Electronic and structural transition on time domain: After excitation to charge transfer state (MLCT) the Fe(bpy)3 complex (negative amplitude signal) gets trapped in magnetic switched state  (positive amplitude signal), and executes coherent “breathing-like” motions.

Observing switching of Molecules using Free Electron Lasers

Free electron lasers (FELs) like SwissFEL help scientists to understand the mechanisms that switch properties of materials which are the basis for functions in electronics, solar cells, chemistry and biology. By using ultrashort X-ray pulses it becomes possible to visualize the ultrafast rearrangements of electrons and atoms that enable the properties to switch in molecules or crystals.