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 noncentrosymmetric ferromagnet Cr11Ge19 with Nowotny chimney ladder structure. Using Lorentz transmission electron microscopy,we reportthe formationofbi-Skyrmions,i.e.,pairs ofspinvortices 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
Synchrotron Radiation and Nanotechnology (SYN)

17 November 2017

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PSI spin-off GratXray wins Swiss Technology Award 2017

Research Using Synchrotron Light Human Health

A spin-off from PSI has received this year's Swiss Technology Award: The young company GratXray is developing a new method for early diagnosis of breast cancer.

16 March 2017

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3-D X-ray imaging makes the finest details of a computer chip visible

Media Releases Materials Research Micro- and Nanotechnology Matter and Material Research Using Synchrotron Light

Researchers at the PSI have made detailed 3-D X-ray images of a commercially available computer chip. In their experiment, they examined a small piece that they had cut out of the chip beforehand. This sample remained undamaged throughout the measurement. It is a major challenge for manufacturers to determine if, in the end, the structure of their chips conforms to the specifications. Thus these results represent one important application of an X-ray tomography method that the PSI researchers have been developing for several years.
General Energy (ENE)

26 September 2017

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Atmosphere in X-ray light

PSI researchers have developed an experimental chamber in which they can recreate atmospheric processes and probe them with unprecedented precision, using X-ray light from the Swiss Light Source SLS. In the initial experiments, they have studied the production of bromine, which plays an essential role in the decomposition of ozone in the lower layers of the atmosphere. In the future, the new experiment chamber will also be available for use by researchers from other scientific fields.
Biology and Chemistry (BIO)

23 December 2016

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A three-dimensional movie of structural changes in bacteriorhodopsin

Snapshots of bacteriorhodopsin
Bacteriorhodopsin is a membrane protein that harvests the energy content from light to transport protons out of the cell against a transmembrane potential. Nango et al. used timeresolved serial femtosecond crystallography at an x-ray free electron laser to provide 13 structural snapshots of the conformational changes that occur in the nanoseconds to milliseconds after photoactivation. These changes begin at the active site, propagate toward the extracellular side of the protein, and mediate internal protonation exchanges that achieve proton transport.
SwissFEL

First lasing in SwissFEL test facility

On the 15th of January 2014, first lasing was achieved in the SwissFEL injector test facility. This is a great success on the way towards SwissFEL, the future hard x-ray free-electron laser that is currently under construction at PSI. It proves the successful functioning of many key components together in a larger system as required for SwissFEL. Furthermore, this is the very first operation of a free-electron laser in Switzerland. Since 2010, PSI has been operating a test facility to study and optimize the electron source for SwissFEL. Over the last years, the test facility was advanced to one of the most brilliant electron sources in the world, and during the last shutdown end of 2013, a first undulator - a highly precise periodic array of magnets - was installed in the facility. This innovative type of undulator is an in-vacuum design with a very small period length of only 15 mm, that was specifically developed for SwissFEL. During the very first beam time after the installation of the undulator, the electron beam could be successfully tuned to pass the undulator with low losses - this is very important to prevent radiation damage to the sensitive 1060 permanent magnets of the undulator. The electrons generate spontaneous radiation when passing the undulator, and this radiation was detected with scintillator screen monitors. In a next step, the electron beam was strongly compressed in a bunch compressor chicane to generate a very large charge density, which is required for the FEL process. This initiated the free-electron lasing process, leading to an exponential increase of the emitted radiation along the undulator. An electron beam with an energy of 220 MeV and a bunch charge of 200 pC was used in that process, and first lasing was detected at a wavelength of around 80 nm. By adjusting the gap of the undulator, the wavelength of the emitted laser light could be tuned over one octave from around 45 to 90 nm
Facility: SwissFEL
Reference: Hans Braun; hans.braun@psi.ch; Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland