Scientific Highlights from PSI's research divisions


Condensed Matter Research with Neutrons and Muons (NUM)

19 January 2018

Low-Field Bi-Skyrmion Formation in a Noncentrosymmetric Chimney Ladder Ferromagnet

The real-space spin texture and the relevant magnetic parameters were investigated for an easy-axis non-centrosymmetric ferromagnet Cr11Ge19 with Nowotny chimney ladder structure. Using Lorentz transmission electron microscopy,we report the formation of bi-Skyrmions,i.e., pairs of spin vortices with opposite magnetic helicities. The quantitative evaluation of the magnetocrystalline anisotropy and Dzyaloshinskii-Moriya interaction (DMI) proves that the magnetic dipolar interaction plays a more important role than the DMI on the observed bi-Skyrmion formation. Notably, the critical magnetic field value required for the formation of bi-Skyrmions turned out to be extremely small in this system, which is ascribed to strong easy-axis anisotropy associated with the characteristic helix crystal structure. The family of Nowotny chimney ladder compounds may offer a unique material platform where two distinctive Skyrmion formation mechanisms favoring different topological spin textures can become simultaneously active.
Facility: SINQ

Reference: R. Takagi et al, Physical Review Letters 120, 037203 (2018)

Read full article: here
Photon Science Division (PSD)

1 March 2019

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Towards X-ray Transient Grating Spectroscopy at SwissFEL

The high brilliance of new X-ray sources such as X-ray Free Electron Laser opens the way to non-linear spectroscopies. These techniques can probe ultrafast matter dynamics that would otherwise be inaccessible. One of these techniques, Transient Grating, involves the creation of a transient excitation grating by crossing X-ray beams on the sample. Scientists at PSI have realized a demonstration of such crossing by using an innovative approach well suited for the hard X-ray regime. The results of their work at the Swiss Free Electron Laser have been published in the journal Optics Letters.

1 February 2019

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Virtual lens improves X-ray microscopy

Media Releases Matter and Material Research Using Synchrotron Light

A method developed by PSI researchers makes X-ray images of materials even better. The researchers took a number of individual images while moving an optical lens. From these, with the help of computer algorithms, they generated one overall image.

4 January 2019

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Dr Yasin Ekinci elected as Fellow of SPIE

Dr. Yasin Ekinci, Head of the Advanced Lithography and Metrology Group and ad interim Head of the Laboratory for Micro and Nanotechnology, has been elected to the grade of Fellow of The International Society for Optics and Photonics (SPIE).

1 January 2019

SESAME beamline for tomography project (BEATS) is launched

On 1st January 2019, the European Horizon 2020 project BEAmline for Tomography at SESAME (BEATS) was launched with the objective to design, procure, construct and commission a beamline for hard X-ray full-field tomography at the SESAME synchrotron in Jordan. The European grant is worth 6 million euros and will span a four-year period from beginning 2019 to end 2022.

17 December 2018

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First femtosecond protein pump-probe measurements at SwissFEL

A major milestone in the commissioning of SwissFEL has been reached: the first pump-probe experiments on proteins have been successfully carried out. Crystals of several retinal-binding proteins were delivered in a viscous jet system and a femtosecond laser was used to start the isomerization reaction. Microsecond to sub-picosecond snapshots were then collected, catching the retinal proteins shortly after isomerization of the chromophore.
General Energy (ENE)

13 December 2018

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2018 Highly Cited Researchers

Three LAC researchers were highly cited in 2018.

23 October 2018

Electron crystallography for everyone

Recent advances in electron crystallography published in Angewandte Chemie and highlighted by Science, Chemical & Engineering News and ScienceNews!

Under the lead of LSK member, "Rapid structure determination of microcrystalline molecular compounds using electron diffraction", published in Angewandte Chemie International Edition https://onlinelibrary.wiley.com/doi/abs/10.1002/anie.201811318 has attracted great attention in the chemistry community.

17 October 2018

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Why the Little Ice Age ended in the middle of the 19th century

Media Releases Energy and Environment Environment

In the first half of the 19th century, a series of large volcanic eruptions in the tropics led to a temporary global cooling of Earth's climate. That Alpine glaciers grew and subsequently receded again during the final phase of the so-called Little Ice Age was due to a natural process. This has now been proven by PSI researchers on the basis of ice cores.

29 June 2018

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Brennstoffzellen zum Durchbruch verhelfen

Wasserstoff gilt als vielversprechende Alternative für eine Zukunft ohne fossile Energieträger. Um Brennstoffzellen weiterzuentwickeln und für einen Markteintritt vorzubereiten, verstärkt die Empa die Zusammenarbeit mit der H2 Energy Holding AG und dem Paul Scherrer Institut (PSI).
Biology and Chemistry (BIO)

22 August 2018

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A biotechnological revolution

Biology Medical Science Human Health Radiopharmacy

Gebhard Schertler is head of the research division Biology and Chemistry at the Paul Scherrer Institute PSI and professor for Structural Biology at ETH Zurich. In this interview he talks about biological research at PSI and the future of drug development.

14 June 2018

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Biological light sensor filmed in action

Media Releases Biology SwissFEL

Using X-ray laser technology, a team led by researchers of the Paul Scherrer Institute PSI has recorded one of the fastest processes in biology. In doing so, they produced a molecular movie that reveals how the light sensor retinal is activated in a protein molecule. Such reactions occur in numerous organisms. The movie shows for the first time how a protein efficiently controls the reaction of the embedded light sensor.
Nuclear Energy and Safety (NES)

13 December 2018

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EPFL Adjunct Professorship to Christopher Mudry

Dr Christopher Mudry, who joined PSI in 1999 and is Research Group Leader of the Condensed Matter Theory Group at PSI since 2009, was awarded the title of Adjunct Professor at EPF Lausanne with the following citation. "Dr Christopher Mudry is a highly acclaimed theoretical physicist. He is regarded as one of the world’s leading experts on the quantum field theory of condensed matter and in the rapidly developing field of the topological properties of matter."

3 December 2018

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Progress in non intrusive laser based measurements of gas-phase thermoscalars and supporting modeling near catalytically reacting interfaces



Heterogeneous and combined hetero/homogeneous chemical processes have attracted increased attention in many energy conversion systems, which include large scale power generation, microreactors for portable power generation, household burners, fuel processing technologies and automotive exhaust gas aftertreatment. Progress in such systems crucially depends on the development of catalysts with enhanced activity and thermal stability and on the comprehensive understanding of the fundamental processes occurring near gas solid reacting interfaces. Recent advances in non intrusive lased based measurements of gas phase thermoscalars over the catalyst boundary layer are reviewed. Such measurements, combined with theoretical analyses and numerical simulations, have fostered fundamental investigations of the catalytic and gas phase chemical processes and their coupling at industrially relevant operating conditions. The methodology for assessing local catalytic reaction rates and validating gas phase reaction mechanisms under steady conditions using 1D Raman and planar laser induced fluorescence (PLIF) of radical species, respectively, is presented first. Progress in the measurement of minor and major stable species using PLIF is outlined and the potential of this technique as a suitable method for assessing the catalytic reactivity under dynamic operating conditions is discussed. State of the art numerical modeling necessary for the interpretation of the measurements is presented in parallel with the laser based techniques. Turbulence modeling, direct numerical simulation (DNS) and near wall non intrusive measurements of species concentrations and velocity have clarified aspects of the complex interplay between interphase turbulent transport and hetero /homogeneous kinetics. Controlling parameters are the competition between the heterogeneous and homogeneous reaction pathways, diffusional imbalance of the deficient reactant, flow laminarization induced by the hot catalytic walls, and fuel leakage through the gaseous reaction zone that leads to concurrent catalytic and gas phase combustion. Experimental needs for assessing turbulent fluctuations of catalytic reaction rates as well as for investigating intrinsic instabilities (heterogeneously or homogeneously driven) are discussed. Future directions for combining in situ surface science diagnostics with in situ non intrusive gas phase thermoscalar diagnostics and for advancing current numerical tools are finally proposed.
Division Large Research Facilities (GFA)

1 April 2018

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Outstanding high gradient performances of two test structures produced at PSI for the CLIC project

X-band (12 GHz) radio-frequency (RF) accelerating structures are under consideration for future free electron lasers, medical linacs and linear colliders. Two such structures, built by PSI in the framework of a CERN/PSI collaboration, are currently being tested at high power at CERN. They are reported to have reached an accelerating gradient in excess of 115 MV/m (CERN Courier, April 2018, http://cerncourier.com/cws/article/cern/71293), making them among the best X-band structures to have been tested by the CERN Linear Collider project group. The structures have benefitted from the fabrication protocols used for the SwissFEL C-band structures. The gradient continues to improve with further “conditioning” at CERN. For structure “aficionados” a recent conditioning curve (courtesy of CERN) shows structure T24PSI1 approaching 120 MV/m. The structures were financed by an SNF FLARE* grant 20FL20_147463.
* Funding for LArge international REsearch projects.