Data Science

Alloy 182 RPV Steel Weldline

Assessment of stress corrosion cracking incidents in Alloy 182 – reactor pressure vessel dissimilar metal welds

Several stress corrosion cracking (SCC) incidents recently occurred in Alloy 182 - reactor pressure vessel (RPV) dissimilar metal welds in boiling water reactors (BWR). These SCC cracks tend to grow towards the RPV due to weld microstructure and residual stress profiles and might grow into the RPV. They thus represent a serious potential safety concern. PSI has evaluated under which conditions such cracks could grow into the RPV and also developed SCC crack growth disposition curves for the RPV steels that can be used for safety assessments of such cracks. With these curves that were recently accepted as a new Code Case N-896 in the ASME Boiler and Pressure Vessel Code, sufficient safety margins could be demonstrated for such crack configurations with the current inspection intervals of the periodic in-service inspection.

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Possible room-temperature signatures of unconventional 4f-electron quantum criticality in YbMn6Ge6−xSnx

We investigate the Sn composition dependence of the Yb valence and local magnetization in YbMn6Ge6−xSnx (4.25 􏰁≤x≤ 5.80) using x-ray absorption spectroscopy (XANES) and x-ray magnetic circular dichroism at the Yb L3 edge. In these materials, where Mn is ferromagnetically ordered, we observe a decrease of the Yb valence upon reducing the chemical pressure by Sn doping and a suppression of the Yb magnetic moment for strongly hybridized  4f states (ν ∼ 2.77).

Pic 1-4 LRT Highlight 01-2020

Nuclear Data – Towards a Stronger Link between Nuclear Physics and Nuclear Simulations

All matter in the universe is made of atoms and all atoms are made of particles. Spontaneous changes within atoms as well as collisions between atoms and surrounding particles are nuclear reaction processes guided by nuclear physics laws. To simulate these processes using computer models, probabilities for the various involved nuclear reactions are required. This is precisely the role of nuclear data: supply the computational models with evaluated quantities representing these nuclear reaction probabilities.

Through this, nuclear data can effectively be seen as the fundamental link between nature and any computer simulation involving nuclear reactions. It is thus of primary importance to continuously improve knowledge on nuclear data. In that context, researchers at the laboratory for reactor physics and thermal-hydraulics have recently focused on the development and application of Bayesian frameworks combining both differential and integral experiments for the improvement of nuclear data. By considering the different experiments together, the aim is to achieve enhancements of the nuclear data evaluations while preserving the basic nuclear physics sum rules.

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Assessing Resilience of Europe's Natural Gas Network

FRS researchers used open-​sourced information to access the disruption performance of the European Natural Gas Network, presenting a supply grade mapping for the case of Italy.

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Magnetism and anomalous transport in the Weyl semimetal PrAlGe: possible route to axial gauge fields

In magnetic Weyl semimetals, where magnetism breaks time-reversal symmetry, large magnetically sensitive anomalous transport responses are anticipated that could be useful for topological spintronics. The identification of new magnetic Weyl semimetals is therefore in high demand, particularly since in these systems Weyl node configurations may be easily modified using magnetic fields. Here we explore experimentally the magnetic semimetal PrAlGe, and unveil a direct correspondence between easy-axis Pr ferromagnetism and anomalous Hall and Nernst effects. 

Anna Soter

Anna Sótér starts Ambizione fellowship

Anna Sótér has started an Ambizione fellowship at ETH Zurich and PSI. Her project is dedicated to developing a novel source of cold muonium atoms, which will be used for a new interferometry experiment that enables testing the weak equivalence principle by directly probing gravitational interaction of antimatter.

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Wrinkles and wrinklons: magnetic films with tuneable topographies

Sebastian Gliga has been awarded an SNF Spark grant to investigate the possibility of combining magnetic thin films with graphene to create logical devices. As electronic components, such as those found in computer CPUs, are miniaturized, they generate waste heatand alternative schemes are being explored to create novel data processing architectures. This project, to be carried out in the Microspectroscopy group (PSD), aims to exploit the tunable topography of graphene to create magnetic systems, which allow simultaneously guiding spin waves and performing logical operations based on spin wave interference. 

Thermometerhalterung

Thermometerhalterung für Ölbäder

Einen neu entwickelten Thermometerhalter für die Laboranten EFZ, Fachrichtung Chemie erleichtert nun die Arbeit, dies mit grosser Unterstützung der Lernenden Polymechaniker EFZ.

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Topological Magnetic Phase in the Candidate Weyl Semimetal CeAlGe

We report the discovery of topological magnetism in the candidate magnetic Weyl semimetal CeAlGe. Using neutron scattering we find this system to host several incommensurate, square-coordinated multi-k⃗ magnetic phases below TN. The topological properties of a phase stable at intermediate magnetic fields parallel to the c axis are suggested by observation of a topological Hall effect. 

OER/LOER and dissolution/ redeposition mechanism

Energy Conversion Processes with Perovskite-type Materials

Mixed oxides derived from the perovskite structure by combination of A- and B-site elements and by partial substitution of oxygen provide an immense playground of physico-chemical properties. Here, we give an account of our own research conducted at the Paul Scherrer Institute on perovskite-type oxides and oxynitrides used in electrochemical, photo(electro)chemical and catalytic processes aimed at facing energy relevant issues.

Oxygen diffusion

Oxygen diffusion in oxide thin films grown on SrTiO3

SrTiO3 thin films were grown on 18O-exchanged SrTiO3 single crystalline substrates by pulsed-laser deposition, rf sputtering, and oxide molecular-beam epitaxy to study their oxygen diffusion depth profiles using secondary ion mass spectrometry and elastic recoil detection analysis depth profiling. The oxygen depth profiling shows that SrTiO3 films prepared with the three different deposition techniques will take oxygen from the substrate, even at room temperature. This confirms that the substrate is one possible oxygen source for the growth of oxide thin films independent of the physical vapor deposition technique employed. It was also found that a reactive oxygen environment changes the oxygen composition of the substrate during the growth of a film and partly replaces 18O with 16O up to a depth of several tens of nm. These findings imply that SrTiO3 and therefore other ion conducting oxide substrates, which are commonly used as platforms for thin film growth, can be considered capricious in nature with respect to oxygen chemistry and lattice constants.

Illustration of the crystal structure of (MA)PbBr3

Ultrafast diffuse x-ray scattering of a hybrid perovskite crystal

Organic–inorganic ‘hybrid’ perovskites have recently gained attention as a low-cost alternative to silicon solar cells. However, many properties of these materials are still poorly understood. In particular, how imperfections in the crystals, which can be both static or dynamic, affect energy transport remains unclear.

PSI2019

Workshop on the Physics of Fundamental Symmetries and Interactions

The 5th Workshop on the Physics of Fundamental Symmetries and Interactions (PSI2019) took place from 20 to 25 October 2019 at PSI, bringing together 200 scientists from all over the world working on some of today’s most precise particle-physics experiments at the low-energy frontier.

Magnetic double spiral

Field-Induced Double Spin Spiral in a Frustrated Chiral Magnet

X-rays and neutrons has been used to investigate the correlation between structural and magnetic chirality in magnetic fields and its impact on the polarization in multiferroic langasites. A long wavelength modulation of the magnetic structure has been found, and it is shown that the chirality of the crystals structure connects to chirality of the magnetic structure that leads to an additional electric polarization in this field induced phase, which, depending on the christal chirality, can either increase the electric polarization or lead to a reversal of it for increasing magnetic fields. The theoretical description based on allowed Lifshitz invariants intriguingly contain all the essential ingredients for the realization of topologically stable antiferromagnetic skyrmions.

Luo et al

Determination and evaluation of the nonadditivity in wetting of molecularly heterogeneous surfaces

Every folded protein presents an interface with water that is composed of domains of varying hydrophilicity/-phobicity. Many simulation studies have highlighted the nonadditivity in the wetting of such nanostructured surfaces in contrast with the accepted theoretical formula that is additive. We present here an experimental study on surfaces of identical composition but different organization of hydrophobic and hydrophilic domains.

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Florian Döring received the PSI Founder Fellowship

A new PSI spin-off is on the horizon: Dr. Florian Döring, PostDoc in the Laboratory for Micro- and Nanotechnology, received a PSI Founder Fellowship at Park Innovaare.

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Assessment of electricity supply resilience

Researchers from FRS and the Paul Scherrer Institute have developed the Electricity Supply Resilience Index (ESRI) to measure electricity supply resilience in 140 countries.

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TecDay: LMX meets Hohe Promenade

TecDay is an SATW initiative that was developed at the Kantonsschule Limmattal in 2007 and has since been rolled out to more than 60 secondary schools across Switzerland. By the end of 2017 it had reached  around 45,000 students and 5,000 teachers. In December 2019 the LMX contributed in one module, that received a total of 16 students over the course of a morning. The module was organized in three different “stations”, each one focusing on one topic or area that the group is working on.

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Fascinating colloquium about the 200 Swiss frank banknote

The designers of the new Swiss banknote series together with the scientific advisor Günther Dissertori from ETHZ gave a fascinating PSI-colloquium on the 200 Swiss Frank banknote.

ultralow-emittance SwissFEL

Generation and measurement of ultralow-emittance electron beams at SwissFEL

The emittance is a fundamental parameter of particle distributions accounting for the average spread of the particles’ positions and momenta. We have generated and characterized intense ultralow-emittance electron beams, setting new standards for electron linear accelerators. The measurements have been carried out at the SwissFEL accelerator of PSI. SwissFEL is one of the few X-ray free-electron lasers (FELs) worldwide, which are cutting-edge research instruments to investigate matter with resolutions at the level of atomic processes.

Ribbon for highly-cited researchers

2019 Highly Cited Researchers

Again in 2019: Three LAC researchers were highly cited.

Overview of the RECAST3D interface.

Towards dynamic feedback control during time-resolved CT at TOMCAT

Researchers from the CWI in Amsterdam and the TOMCAT beamline have developed and implemented a real-time CT reconstruction, visualisation, and on-the-fly analysis approach to monitor dynamic processes as they occur. With processes of  multiple sets of CT slices per second, this represents the next crucial step towards adaptive feedback control of time-resolved in situ tomographic experiments. The results of this study were published in Scientific Reports on December 5, 2019.

Overview of the RECAST3D interface.

Towards dynamic feedback control during time-resolved CT at TOMCAT

Researchers from the CWI in Amsterdam and the TOMCAT beamline have developed and implemented a real-time CT reconstruction, visualisation, and on-the-fly analysis approach to monitor dynamic processes as they occur. With the processing of  multiple sets of CT slices per second, this represents the next crucial step towards adaptive feedback control of time-resolved in situ tomographic experiments. The results of this study were published in Scientific Reports on December 5, 2019.

Jahresschlussapéro 2019

Jahresschlussapéro 2019

Am Mittwoch, 4. Dezember fand der Jahresschlussapéro in der OASE statt. Viele Lernende, Berufsbildnerinnen und Berufsbildner, wie auch weitere Gäste genossen den Anlass in der OASE. Der Leiter der Berufsbildung Paul Kramer hat das Jahr Revue passieren lassen.