Forschung zu Covid-19

Am PSI widmen sich mehrere Projekte wichtigen Forschungsfragen rund um das Coronavirus Sars-CoV-2 und den daraus resultierenden Erkrankungen. Wir informieren über Aktivitäten und Vorhaben, zum Beispiel zu Untersuchungen von Lungengewebe, zur Produktion von Proteinen und Antikörpern oder über Ideen für neue Forschung zu Covid-19.

Nützliche Links

Vopicka et al

One-pot neutron imaging of surface phenomena, swelling and diffusion during methane absorption in ethanol and n-decane under high pressure

We study the gas diffusion in still liquids under gas high pressures. We demonstrate that the pressure-induced gas diffusion, liquid swelling and the liquid surface tension can be measured simultaneously in a one-pot experiment. The measurements are performed using the high-resolution neutron imaging in a non-tactile way. A major advantage of this new method is that the determination of surface tension necessitate no assumptions imposed on the properties of the liquid.

advances_in_long-wavelength_native_phasing_at_x-ray_free-electron_lasers.png

Advances in long-wavelength native phasing at X-ray free-electron lasers

Long-wavelength pulses from the Swiss X-ray free-electron laser (XFEL) have been used for de novo protein structure determination by native single-wavelength anomalous diffraction (native-SAD) phasing of serial femtosecond crystallography (SFX) data.

Kundu PRL

Signatures of a Spin-1/2 Cooperative Paramagnet in the Diluted Triangular Lattice of Y2CuTiO6

We present a combination of thermodynamic and dynamic experimental signatures of a disorder driven dynamic cooperative paramagnet in a 50% site diluted triangular lattice spin-1/2 system: Y2CuTiO6. Magnetic ordering and spin freezing are absent down to 50 mK, far below the Curie-Weiss scale (-θCW) of ∼134 K. 

narrow-band_thz_generation_setup

Narrow-band and tunable intense terahertz pulses for mode-selective coherent phonon excitation

We generate frequency-tunable narrow-band intense fields in the terahertz (THz) range by optical rectification of a temporally modulated near-infrared laser pumping a nonlinear organic crystal.

Yin Nat Comm

Spin-orbit quantum impurity in a topological magnet

Quantum states induced by single-atomic impurities are at the frontier of physics and material science. While such states have been reported in high-temperature superconductors and dilute magnetic semiconductors, they are unexplored in topological magnets which can feature spin-orbit tunability. Here we use spin-polarized scanning tunneling microscopy/ spectroscopy (STM/S) to study the engineered quantum impurity in a topological magnet Co3Sn2S2. We find that each substituted In impurity introduces a striking localized bound state.

 

Smolentsev_2020

The structure of active sites of CoMo/Al2O3 catalysts determined by RIXS spectroscopy.

A fundamental understanding of the active sites in technical CoMo/ Al2O3 catalysts is crucial to improve the production of clean transportation fuels by hydrodesulfurization (HDS), which removes sulfur from fossil fuels. Sulfur dioxide, resulting from fossil fuel combustion, is one of the main causes for acid rain. In situ X-ray spectroscopic experiments at the SuperXAS beamline of the SLS provided insight in the structure and number of active sites (“Co−Mo−S”) in sulfided CoMo/ Al2O3 catalysts. When the Co to Mo ratio is less than 0.1, cobalt forms isolated sites on the MoS2 phase, where the cobalt promoter atoms are in centrosymmetric octahedral coordination with six-sulfur ligands.

Guguchia_PRL

Using Uniaxial Stress to Probe the Relationship between Competing Superconducting States in a Cuprate with Spin-stripe Order

We report muon spin rotation and magnetic susceptibility experiments on in-plane stress effects on the static spin-stripe order and superconductivity in the cuprate system La2−xBaxCuO4 with x = 0.115. An extremely low uniaxial stress of ∼0.1 GPa induces a substantial decrease in the magnetic volume fraction and a dramatic rise in the onset of 3D superconductivity, from ∼10 to 32 K.

Teaser

Used Nuclear Fuel: from Better Characterization to Better Optimization

A safe, economical and environmental friendly disposal of used nuclear fuel represents an essential objective of relevance for all. This guides the approach under development at the laboratory for reactor physics and thermal-hydraulics. Establish higher resolution simulation methods to gain more detailed knowledge on the content of each single nuclear fuel rod ever irradiated in a reactor. Thereafter, use this knowledge to explore optimization approaches that could potentially enlarge the range of disposal options allowing to fulfill the highest level of safety standards while reducing economical costs and geological footprints at the same time.

OAM Imprinting on He Atoms

Photoelectric Effect with a Twist

In a joint research effort, an international team of scientists lead by Prof. Giovanni de Ninno (University of Nova Gorica, Elettra Sincrotrone Trieste) now demonstrated that an OAM-dependent dichroic effect can be observed on photoelectrons. The photoelectrons are released from a sample of He atoms that is excited by the strong extreme ultraviolet light pulses from the FERMI free electron laser, whereas the orbtial momentum is imprinted with an intense infrared laser pulse. The X-ray Optics and Applications group of PSI supported the team with their experience in the creation of OAM beams and during the experiments.

Lehrabschlussfeier 2020

Lehrabschlussfeier 2020

Stolz, mit viel Freunde und dem "nötigen Abstand" durften wir am Freitag, 14. August 25 neue Berufsleute feiern. Sie schlossen ihre Berufslehre mit einem tollen Noten-Durchschnitt und einer Höchstnote von 5.9 ab. Wir gratulieren herzlich und sind sehr stolz auf sie!

Einführungswoche 2020

Einführungswoche 2020

Unter erschwerten Bedingungen haben wir gestartet ...

3D Printing silica aerogels.

3D printing silica aerogels at the micrometer scale

A group of EMPA and ETH Zürich researchers have developed a new method to directly write ink made of silica aerogels in 3D. Thanks to X-ray phase contrast tomography at the TOMCAT beamline they characterized the resulting printed material with different compositions. Their results were published in Nature on August 18, 2020.

3D Printing silica aerogels.

3D printing silica aerogels at the micrometer scale

A group of EMPA and ETH Zürich researchers have developed a new method to directly write ink made of silica aerogels in 3D. Thanks to X-ray phase contrast tomography at the TOMCAT beamline they characterized the resulting printed material with different compositions. Their results were published in Nature on August 18, 2020.

Novel Optics

Novel optics enable better X-ray Free Electron Laser experiments

Our research on multifocus off-axis zone plates was accepted in “Optica”, the highest impact journal of the Optical Society of America. In the paper we report on different ways to combine focusing and beam-splitting functionalities in one single optical element.

Coutinho PRL

Global Fit to Modified Neutrino Couplings and the Cabibbo-Angle Anomaly

Recently, discrepancies of up to 4σ between the different determinations of the Cabibbo angle were observed. In this context, we point out that this “Cabibbo-angle anomaly” can be explained by lepton flavor universality violating new physics in the neutrino sector. However, modified neutrino couplings to standard model gauge bosons also affect many other observables sensitive to lepton flavor universality violation, which have to be taken into account in order to assess the viability of this explanation.

u1x

X-rays illuminate the particle atomic structure of cyan light emitting 6-monolayers CsPbBr3 nanoplatelets by Total Scattering

A cyan light (492 nm) emitting colloidal suspension of CsPbBr3 nanoplatelets in a flask, together with the high-quality XRPD Total Scattering pattern of the suspension measured at the X04SA-MS beamline and the full-nanoparticle structure thereby inferred.

Lehmann Nat Nanotech

Relation between microscopic interactions and macroscopic properties in ferroics

The driving force in materials to spontaneously form states with magnetic or electric order is of fundamental importance for basic research and device technology. The macroscopic properties and functionalities of these ferroics depend on the size, distribution and morphology of domains; that is, of regions across which such uniform order is maintained. Typically, extrinsic factors such as strain profiles, grain size or annealing procedures control the size and shape of the domains, whereas intrinsic parameters are often difficult to extract due to the complexity of a processed material. Here, we achieve this separation ...

 

Cover art of Small 16(33)

Phase contrast microtomography reveals nanoparticle accumulation in zebrafish

Metal-based nanoparticles are a promising tool in medicine – as a contrast agent, transporter of active substances, or to thermally kill tumor cells. Up to now, it has been hardly possible to study their distribution inside an organism. Researchers at the University of Basel in collaboration with the TOMCAT team have used phase contrast X-ray tomographic microscopy to take high-resolution captures of the nanoparticle aggregation inside zebrafish embryos.

The study was published in the journal Small and featured on the cover of its current issue.

Mahrt_Fabian

Welcome to Fabian Mahrt

We gladly announce that Fabian Mahrt has started to work as Postdoc in the Laboratory of Environmental Chemistry. He formally joined the Surface Chemistry group on 1 August 2020 but has started his work actually at the University of British Columbia (UBC), Canada.