Energiewende

The implementation of Focused Ion Beam instruments in material research laboratories during the last decade has not only strongly improved the preparation of very thin specimens for the Transmission Electron Microscope (TEM), in particular at interfaces, but also led to the development of new analysis methods inside the instrument itself. It became a powerful instrument for the analyses of highly radioactive materials, because it allows for the production and analysis of very small specimens that can be then analyzed with very sensitive detectors without strong interference from the radiation field of the specimen itself.

The investigation of the nuclear fuel at very high burnup is critical for evaluating the safety margin for the evaluated fuel in normal as well as in accidental conditions. PSI is one of the very few hot laboratories which possess access to irradiated UO2 fuel with very high burnup from commercial reactors. The application of relevant tools for the investigation, handling and analysis of those highly irradiated materials emphasize the necessary expertise.

Researchers at PSI have established a link between the martensitic transformation, microstructural evolution and the mechanical behavior under multiaxial deformation in a NiTi alloy by using a unique combination of in situ high-resolution Digital Image Correlation (DIC), in situ X-ray diffraction and electron microscopy characterization.

On the 17th of December 2017 SwissFEL saw its first pilot experiment in the Alvra experimental station of the SwissFEL ARAMIS beamline. A team of scientists from the University of Bremen, Krakow and PSI, led by Matthias Vogt (Univ. Bremen) and Chris Milne (PSI)in collaboration with J. Szlachetko, J. Czapla-Masztafiak, W. M. Kwiatek (Inst. of Nucl.Phys. PAN (Krakow), successfully did the first pilot experiment at SwissFEL-Alvra on 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.

The compound Sr_0.5Ce_0.5FBiS₂ belongs to the intensively studied family of layered BiS₂ superconductors. It attracts special attention because superconductivity at T_sc = 2.8 K was found to coexist with local-moment ferromagnetic order with a Curie temperature T_C = 7.5 K. Recently it was reported that upon replacing S by Se T_C drops and ferromagnetism becomes of an itinerant nature.

Throughout 2017, the material α−RuCl₃ has continued to inspire and fascinate those interested in correlated condensed matter. New experimental data now provide unique insight, and pose fresh challenges.

The Charpak-Ritz Prize 2018, jointly awarded by the French Physical Society and the Swiss Physical Society, has been bestowed to Roland Paul Horisberger for his numerous contributions to the development of precision silicon vertex detectors for particle physics experiments as well as for the application of these technologies in X-ray photon sciences.

Jean-Baptiste Mosset from the Laboratory of Particle Physics is the winner of a PSI Founder Fellowship and plans now to commercialise a neutron detector to spot plutonium and uranium. With his new technology, less expensive and more efficient neutron detectors could be developed. In the next 18 months, Mosset wants to further develop his prototype and find out if demand for this technology exists in industry.

The evolution of the interaction between an anionic nanoparticle and a nonionic surfactant and their resultant phase behavior in aqueous solution in the presence of electrolyte and ionic surfactants have been studied. The mixed system of anionic silica nanoparticles (Ludox LS30) with nonionic surfactant decaethylene glycol monododecylether (C12E10) forms a highly stable clear phase over a wide concentration range of surfactant.

Christopher Mudry and his collaborators have shown theoretically how to construct strongly interacting phases of matter that realize topological order in two-dimensional space by strongly coupling quantum wire. Remarkably, their model supports both Abelian topological order (ATO) and non-Abelian topological order (NATO) with a continuous phase transition separating them. Read the full paper here

α-RuCl₃ is a leading candidate material for the observation of physics related to the Kitaev quantum spin liquid (QSL). By combined susceptibility, specific-heat, and nuclear-magnetic-resonance measurements, we demonstrate that α-RuCl₃ undergoes a quantum phase transition to a QSL in a magnetic field of 7.5 T applied in the ab plane. We show further that this high-field QSL phase has gapless spin excitations over a field range up to 16 T.

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. The goal was to study the picosecond dynamics of a light-induced phase transition from a semiconductor to metallic crystal structure in a Titanium Oxide (D).

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.

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. The goal was to study the picosecond dynamics of a light-induced phase transition from a semiconductor to metallic crystal structure in a Titanium Oxide (D).

The prototypical magnetic memory shape alloy Ni2MnGa undergoes various phase transitions as a function of the temperature, pressure, and doping. In the low-temperature phases below 260 K, an incommensurate structural modulation occurs along the [110] direction which is thought to arise from the softening of a phonon mode. It is not at present clear how this phenomenon is related, if at all, to the magnetic memory effect. Here we report time-resolved measurements which track both the structural and magnetic components of the phase transition from the modulated cubic phase as it is brought into the high-symmetry phase.

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.

Molecular dynamics simulations of transient stress drops have been carried out in different regimes on a nanocrystalline Aluminum sample with average grain size of 12 nm. Besides confirming the interpretation of experimental results obtained during in situ X-ray diffraction, the creep simulations performed at 2 or 3 orders of magnitude lower strain rates than usual reveal deformation mechanisms that have not been observed previously.