At PSI, several projects are dedicated to important research questions concerning the Sars-CoV-2 coronavirus and the resulting diseases. We provide information on activities and projects, for example on investigations of lung tissue, on the production of proteins and antibodies or on ideas for new research on Covid-19.
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PSI summer school 2015
The PSI summer school 2015 on Condensed Matter Research will be organized at the Lyceum Alpinum in Zuoz, Switzerland from August 15-21, 2015. International experts and PSI staff members will introduce and deepen your knowledge not only on methods but also on those phenomena, which are presently at the forefront of modern solid state physics and chemistry. The school will be followed by hands-on practical training at the PSI large user facilities SINQ, SμS and SLS. Online registration and detailed information is available from the school's webpage.
Coexistence of 3d-Ferromagnetism and Superconductivity in [(Li1-Fex)OH](Fe1-yLiy)Se
Superconducting [(Li1-xFex)OH](Fe1-yLiy)Se (x≈0.2, y≈0.08) was synthesized by hydrothermal methods and characterized by single-crystal and powder X-ray diffrac- tion. The structure contains alternating layers of anti-PbO type (Fe1-yLiy)Se and (Li1-xFex)OH. Electrical resistivity and magnetic susceptibility measurements reveal superconductivity at 43K.
Fractional excitations in the square-lattice quantum antiferromagnet
Quantum magnets have occupied the fertile ground between many-body theory and low-temperature experiments on real materials since the early days of quantum mechanics. However, our understanding of even deceptively simple systems of interacting spin-1/2 particles is far from complete. The quantum square-lattice Heisenberg antiferromagnet, for example, exhibits a striking anomaly of hitherto unknown origin in its magnetic excitation spectrum.
Shortcut to protein portraits
All living organisms, from bacteria to humans, rely on proteins to perform their vital functions. How these proteins accomplish their tasks depends on their structure. Researchers from the Paul Scherrer Institute have now devised a novel method to determine the crystal structure of proteins using X-ray light, which could also hasten the development of new drugs in future. The study will be published in the journal Nature Methods on 15 December.
A measurement of the neutron to 199Hg magnetic moment ratio
The neutron gyromagnetic ratio has been measured relative to that of the 199Hg atom with an uncertainty of 0.8 ppm. We employed an apparatus where ultracold neutrons and mercury atoms are stored in the same volume and report the result γn/γHg = 3.8424574(30).
Biomasse als Stütze der Energiewende
Mit 80 Teilnehmerinnen und Teilnehmern fand am 2. Dezember am Paul Scherrer Institut PSI die erste Jahreskonferenz des Kompetenzzentrums des Bundes für Bioenergie (SCCER BIOSWEET) statt. Das im Rahmen des Aktionsplans Energieforschung Schweiz gegründete Kompetenzzentrum definierte in der Tagung die Ziele, Strategien und Positionierung der Bioenergie-Forschung vor dem Hintergrund der neuen schweizerischen Energiepolitik.This news release is only available in German.
Short-Range Correlations in the Magnetic Ground State of Na4Ir3O8
The magnetic ground state of the Jeff = 1/2 hyperkagome lattice in Na4Ir3O8 is explored via combined bulk magnetization, muon spin relaxation, and neutron scattering measurements. A short-range, frozen state comprised of quasistatic moments develops below a characteristic temperature of TF = 6K, revealing an inhomogeneous distribution of spins occupying the entirety of the sample volume. Quasistatic, short- range spin correlations persist until at least 20 mK and differ substantially from the nominally dynamic response of a quantum spin liquid. Our data demonstrate that an inhomogeneous magnetic ground state arises in Na4Ir3O8 driven either by disorder inherent to the creation of the hyperkagome lattice itself or stabilized via quantum fluctuations.
Measurement of the parameter ξ″ in polarized muon decay and implications on exotic couplings of the leptonic weak interaction
The muon decay parameter ξ″ has been determined in a measurement of the longitudinal polarization of positrons emitted from polarized and depolarized muons. The result, ξ″ = 0.981 ± 0.045stat ± 0.003syst, is consistent with the Standard Model prediction of unity, and provides an order of magnitude improvement in the relative precision of this parameter. This value sets new constraints on exotic couplings beyond the dominant V-A description of the leptonic weak interaction.
Innovation Award on Synchrotron Radiation 2014 for high-resolution 3D hard X-ray microscopy
The 2014 Innovation Award on Synchrotron Radiation was bestowed to researchers Ana Diaz, Manuel Guizar-Sicairos, Mirko Holler, and Jörg Raabe from the Paul Scherrer Institut, Switzerland, for their contributions to method and instrumentation development, which have set new standards in high-resolution 3D hard X-ray microscopy.
k=0 Magnetic Structure and Absence of Ferroelectricity in SmFeO3
SmFeO3 has attracted considerable attention very recently due to its reported multiferroic properties above room temperature. We have performed powder and single crystal neutron diffraction as well as complementary polarization dependent soft X-ray absorption spectroscopy measurements on floating-zone grown SmFeO3 single crystals in order to determine its magnetic structure. We found a k=0 G-type collinear antiferromagnetic structure that is not compatible with inverse Dzyaloshinskii-Moriya interaction driven ferroelectricity. While the structural data reveal a clear sign for magneto-elastic coupling at the Néel-temperature of ∼675 K, the dielectric measurements remain silent as far as ferroelectricity is concerned.
SwissFEL ready for assembly
Researchers from PSI have spent the last four years developing key technologies for the X-ray laser SwissFEL and subjecting them to the acid test in the injector test facility. Now that the development programme has drawn to a close, the installation of the new large research facility is due to get underway in early 2015.
Ist dies der richtige Zeitpunkt für ein waghalsiges Experiment?
PSI-Direktor Joël Mesot hat sich heute in der Aargauer Zeitung mit einem Gastkommentar zur Debatte um die Ecopop-Initiative geäussert. Lesen Sie hier seinen vollständigen Text.This news release is only available in German.
Das Kompetenzzentrum Speicherung zieht nach einem Jahr Bilanz
Am vergangenen 4. November fand am Paul Scherrer Institut das erste Jahressymposium des Kompetenzzentrum des Bundes für Forschung zu Strom- und Wärmespeicherung (SCCER Heat and Electricity Storage) statt. Vertreter aus den beteiligten Forschungsgruppen sowie aus Industrieunternehmen mit einem Bezug zum Thema Speicherung berichteten in ihren Vorträgen über die jüngsten Fortschritte auf dem Gebiet der Wärme- und Stromspeicherung in der Schweiz. Die Tagung zeigte die Intensität der Transformationen, die von der Energiestrategie 2050 in Gang gesetzt worden sind.This news release is only available in German.
When thawing glaciers release pollutants
As glaciers increasingly melt in the wake of climate change, it is not only the landscape that is affected. Thawing glaciers also release many industrial pollutants stored in the ice into the environment. Now, within the scope of a Swiss National Science Foundation project, researchers from the Paul Scherrer Institute (PSI), Empa, ETH Zurich and the University of Berne have measured the concentrations of a class of these pollutants à polychlorinated biphenyls (PCB) à in the ice of an Alpine glacier accurately for the first time.
A high-pressure hydrogen time projection chamber for the MuCap experiment
The MuCap experiment at the Paul Scherrer Institute performed a high-precision measurement of the rate of the basic electroweak process of nuclear muon capture by the proton, μ- + p → n + νμ. The experimental approach was based on the use of a time projection chamber (TPC) that operated in pure hydrogen gas at a pressure of 10 bar and functioned as an active muon stopping target. The TPC detected the tracks of individual muon arrivals in three dimensions, while the trajectories of outgoing decay (Michel) electrons were measured by two surrounding wire chambers and a plastic scintillation hodoscope.
Competitive thanks to high pressure
Various basic materials for the chemical industry are manufactured using technology developed by the Ticino based company, Casale. The chemical compounds produced serve to make products like synthetic fertilisers or Plexiglas. In co-operation with PSI, Casale aims to make these production processes even more efficient as basic chemical products are export goods that face stiff competition around the globe. Tiny differences in production costs can be decicive when it comes to which licence a plant operator goes for.
During winter smog fire places put cars in the shade
On winter smog days in Switzerland wood burning is the main source of harmful carbon-containing fine particles. This is revealed by a large-scale Swiss study on fine particle pollution conducted over a five-year period by scientists at the Paul Scherrer Institute (PSI), the University of Bern and ETH Zurich.
Puzzling new behaviour observed in high-temperature superconductors
New effect might be important for emergence of High-Temperature SuperconductivityAn international team of researchers has observed a new, unexpected kind of behaviour in copper-based high-temperature superconductors. Explaining the new phenomenon à an unexpected form of collective movement of the electrical charges in the material à poses a major challenge for the researchers. A success in explaining the phenomenon might be an important step toward understanding high-temperature superconductivity in general. The crucial experiments were conducted at the Paul Scherrer Institute.
Molecular Scale Dynamics of Large Ring Polymers
We present neutron scattering data on the structure and dynamics of melts from polyethylene oxide rings with molecular weights up to ten times the entanglement mass of the linear counterpart. The data reveal a very compact conformation displaying a structure approaching a mass fractal, as hypothesized by recent simulation work. The dynamics is characterized by a fast Rouse relaxation of subunits (loops) and a slower dynamics displaying a lattice animal-like loop displacement.
A large research facilities disappears in the woods
The building of the new PSI large research facility SwissFEL in Würenlingen forest could only enjoy the sunshine for a brief spell: it is now disappearing under a mound of earth. This superstructure is one of the measures taken to integrate the facility as harmoniously as possible into the natural environment.
Multiferroic Properties of o−LuMnO3 Controlled by b-Axis Strain
Strain is a leading candidate for controlling magnetoelectric coupling in multiferroics. Here, we use x-ray diffraction to study the coupling between magnetic order and structural distortion in epitaxial films of the orthorhombic (o-) perovskite LuMnO3. An antiferromagnetic spin canting in the E-type magnetic structure is shown to be related to the ferroelectrically induced structural distortion and to a change in the magnetic propagation vector.
Useful for spintronics: Big surprises in a thin surface region
The need for ever faster and more efficient electronic devices is growing rapidly, and thus the demand for new materials with new properties. Oxides, especially ones based on strontium titanate (SrTiO3), play an important role here. A collaborative project headed by scientists from the PSI has now revealed properties of strontium titanate that make it an important base material for applications in spintronics.
Structural and magnetic dynamics in the magnetic shape-memory alloy Ni2MnGa
Magnetic shape-memory Heusler alloys are multiferroics stabilized by the correlations between electronic, magnetic, and structural order. To study these correlations we use time-resolved x-ray diffraction and magneto-optical Kerr effect experiments to measure the laser induced dynamics in a Heusler alloy Ni2MnGa film and reveal a set of time scales intrinsic to the system.
New Renewables on integration course
The Swiss government’s Energy Strategy 2050 includes a significant expansion of renewable energy such as solar and wind power. The integration of this electric energy, which is produced in a decentralised way and with temporal fluctuations, poses a major challenge for power grids. One possible solution involves using the electricity surplus that would otherwise overload the grid for the production of gases such as hydrogen or methane. The electric energy would thus be stored temporarily in form of chemical energy. These gaseous energy carriers can be converted back into electricity, heat or kinetic energy (in gas engines) at a later date as and when needed. Dubbed power to gas, the concept is the focus of the new Energy System Integration (ESI) Platform at PSI.
Foundation Stone Ceremony Marks Scientific Importance of ESS
Today, several hundred members of the European scientific community gathered at the European Spallation Source (ESS) construction site in Lund, Sweden, for the ESS Foundation Stone Ceremony. The event was held to lay the foundation’ both for the new facility, which has recently begun construction, and for a new generation of science in Europe.
The last piece of the puzzle
Julia H. Smith is a postdoctoral fellow working on detectors for the SwissFEL x-ray free electron laser, which can be envisioned as the eyes of the new PSI large research facility. During her time at PSI, she has a good chance of accompanying her detector up to its use at the new facility. Even more important than witnessing the first experiments at SwissFEL is acquiring new knowledge and skills during my time as a postdoc at PSI. Smith would like to continue working in the field of detectors and technology development after her postdoc – at a company or at another research institute.
Direct Spectroscopic Observation of a Shallow Hydrogenlike Donor State in Insulating SrTiO3
We present a direct spectroscopic observation of a shallow hydrogenlike muonium state in SrTiO3 which confirms the theoretical prediction that interstitial hydrogen may act as a shallow donor in this material. The formation of this muonium state is temperature dependent and appears below ∼70 K. From the temperature dependence we estimate an activation energy of ∼50 meV in the bulk and ∼23 meV near the free surface. The field and directional dependence of the muonium precession frequencies further supports the shallow impurity state with a rare example of a fully anisotropic hyperfine tensor.
The μ → eγ decay in a systematic effective field
We implement a systematic effective field theory approach to the benchmark process μ → eγ, performing automated one-loop computations including dimension 6 operators and studying their anomalous dimensions. We obtain limits on Wilson coefficients of a relevant subset of lepton-flavour violating operators that contribute to the branching ratio μ → eγ at one-loop.
Giants who control miniscule particles
Magnets are the unsung heroes in particle accelerators because they keep protons or electrons on track. But such magnets have very little in common with the small ones on the domestic fridge door. Quite a few of the magnets at PSI are heavier and bulkier than the fridge itself, yet despite this they are also masterpieces of precision and control.
A reliable type from the 1980s
The source of the proton beam at PSI is a retro-style Cockcroft-Walton linear accelerator. Since 1984 it has been the first acceleration stage for protons which are taken up to around 80 percent of the speed of light by two further ring accelerators. This has resulted in the generation of a significant proton beam over decades, and which has even held the world record as the highest performing beam since 1994 thanks to ongoing retrofitting.