Transition énergétique

For the first time in the history of the High Intensity Proton Accelerator the availability of the facility reached an outstanding value of 95% in 2015 with a record value of 99.3% in week 44. In comparison to the two previous years this corresponds to a reduction of the downtime by 50%. The user operation in 2015 was started as scheduled and already in the first week the machine was available 97% of the scheduled beam time. In addition to the smooth operation of the facility, high intensity beam experiments could regularly be performed with currents of up to 2.4 mA. nu

The family of iron-based superconductors has recently acquired a new member material, FeS. Theoretically, this compound has been shown to have electronic structure similar to that of the superconducting FeSe. However, contradictory ground states have been predicted for FeS. In this work, a collaboration of authors from Switzerland and Germany use muon spin rotation and relaxation to show that weak-moment magnetism microscopically coexists with bulk superconductivity.

Drei Jahre in Folge hat Jenna Poonoosamy den Preis für die beste Präsentation am Doktorandentag im Bereich Nukleare Energie und Sicherheit (NES) am Paul Scherrer Institut PSI erhalten. Poonoosamy stammt ursprünglich von der Insel Mauritius im Indischen Ozean. Schon in der Schule interessierte sie sich vor allem für Chemie. «Die meisten meiner Freunde wollten in die Wirtschaft», erzählt sie. «Mich dagegen haben die Naturwissenschaften fasziniert.» Und so zog sie nach der Schule zum Chemie-Studium nach Paris. Und kam später für ihre Doktorarbeit ans PSI.

The Paul Scherrer Institut is building an X-ray free electron laser (SwissFEL) providing a source of intense, ultra-short pulses of coherent radiation in the wavelength range of 0.1 nm to 0.7nm. For the hard X-ray beam line, the magnet section in GFA/ATK has the responsibility for the design, the procurement and the magnetic qualification of 267 electro-magnets of 22 different types. Several design studies were performed in an attempt to meet the required magnet specifications while optimizing construction and operation cost.

The biological influence of radiation on living matter has been studied for years; however, several questions about the detailed mechanism of radiation damage formation remain largely unanswered. Among all biomolecules exposed to radiation, DNA plays an important role because any damage to its molecular structure can affect the whole cell and may lead to chromosomal rearrangements resulting in genomic instability or cell death.

On the 25th of January, the first "completed" undulator has been transported to its final position in the SwissFEL tunnel. The 1064 permanent magnets of this undulator where shimmed to the sub-micrometer level and the magnetic profile has been carefully measured for the full gap range. Twelve of such undulators will be installed until October 2016!

The phase behavior of nanoparticle (silica)−polymer (polyethylene glycol) system without and with an electrolyte (NaCl) has been studied. It is observed that nanoparticle−polymer system behaves very differently in the presence of electrolyte. In the absence of electrolyte, the nanoparticle−polymer system remains in one-phase even at very high polymer concentrations.

The mechanical performance of materials at oil/water interfaces after consumption is a key factor affecting hydrophobic drug release. In this study, we methylated the surface of nanocrystalline cellulose (NCC) by mercerization and dimethyl sulfate exposure to produce thermosensitive biopolymers. These methylated NCC (metNCC) were used to investigate interfacial thermogelation at air/water and medium-chain triglyceride (MCT)/water interfaces at body temperature.

If a ball is rolled up a hill with less kinetic energy than the potential energy at the top, it will return eventually, and stays bound in the valley. Tunnelling is a distinctly quantum mechanical phenomenon, in which such balls can magically cross the hill, and appear in the neighbouring valley, as if going through a tunnel. In order for this to happen with a non-negligible probability, the ball has to be small and the barrier, i.e. the hill, sharp.

The present Letter reports on self-diffusion in amorphous silicon. Experiments were done on ²⁹Si/^natSi heterostructures using neutron reflectometry and secondary ion mass spectrometry. The diffusivities follow the Arrhenius law in the temperature range between 550 and 700°C with an activation energy of (4.4 ± 0.3) eV.

Mirrors are key elements to distribute and shape the Xray beam generated by the undulators of the SwissFEL facility. They are essential tools to guide and focus the light according to the specific users requirements and should do this without noticeable effects on the beam quality. A quantitative measure is the quality of the beam wavefront. The wavefront must be conserved by the optical elements in the SwissFEL beamlines within a fraction of the wavelength which can be as short as one Angstrom in the case of Aramis. There are only few companies in the world, who are able to fabricated such ultraprecise mirrors.

The performance and degree of efficiency of industrial transformers are directly influenced by the magnetic properties of high-permeability steel laminations (HPSLs). Industrial transformer cores are built of stacks of single HPSLs. While the insulating coating on each HPSL reduces eddy-current losses in the transformer core, the coating also induces favorable inter-granular tensile stresses that significantly influence the underlying magnetic domain structure.

Mirrors are key elements to distribute and shape the Xray beam generated by the undulators of the SwissFEL facility. They are essential tools to guide and focus the light according to the specific users requirements and should do this without noticeable effects on the beam quality. A quantitative measure is the quality of the beam wavefront.

Obwohl die Schweiz aus der Kernenergie aussteigt, muss sie eine Lösung für das in den Kernkraftwerken, aber auch in Medizin, Industrie und Forschung entstandene, radioaktive Material finden. Daher stellt sie sich einer aussergewöhnlichen, verantwortungsvollen Aufgabe: Sie sucht einen Ort, an dem sie ihre radioaktiven Abfälle mehrere hunderttausend Jahre lang sicher lagern kann. So lange, bis sie von selbst die Radioaktivität natürlicher Gesteine erreicht haben.

A new type of detector developed by Dr. van Genderen enables the structure determination of pharmaceutical compounds with electron diffraction at room temperature. The group concentrate on expanding this new technique to macromolecular compounds.

The transfer rate of a probe molecule across the interfacial layer of a water-in-oil (w/o) microemulsion was investigated using a combination of transverse field muon spin rotation (TF-μSR), avoided level crossing muon spin resonance (ALC-μSR), and Monte Carlo simulations. Reverse micro-emulsions consist of nanometer-sized water droplets dispersed in an apolar solvent separated by a surfactant monolayer.

The discovery of exceptionally well-preserved, tiny fossil seeds dating back to the Early Cretaceous corroborates that flowering plants were small opportunistic colonizers at that time, according to a new Yale-led study.

The determination of the mass density of cellular compartments is one of the many analytical tools that biologists need to unravel the extremely complex structure of biological systems. Cryo X-ray nanotomography reveals absolute mass density maps of frozen hydrated cells in three dimensions.

A new kind of 2DEG is found by inserting two atomic layers of the antiferromagnetic and insulating compound EuTiO₃ between LaAlO₃ and SrTiO₃. The 2DEG is found to exhibit besides a superconducting ground state, a strong spin-polarization. The magnetism of Eu and Ti was studied by XMCD at the X-Treme beamline in SLS.