Data Science

The recent improvement on the capability of neutron imaging that allows acquiring neutron images with isotropic spatial resolution of about 5 micrometres is demonstrated. This is achieve by combining the tailor-made high-numerical aperture magnifying optics together with a thin isotopically-enriched ¹⁵⁷Gd₂O₂S:Tb scintillator screens (see Trtik & Lehmann, NIM-A 788 (2015) 67-70). The newly achieved level of the spatial resolution represents about 30% enhancement compared to the first prototype (see Trtik et al, Physics Procedia 69 (2015) 169-176) and approximately six-fold enhancement in the spatial resolution capabilities available for the general users community at PSI before the start of the Neutron Microscope project.

The activation and conversion of hydrocarbons is one of the most important challenges in chemistry. This work shows that isolated Co(II) sites are catalysts for a number of hydrocarbon conversion reactions, such as the dehydrogenation of propane, the hydrogenation of propene, and the trimerization of terminal alkynes. The data are consistent with all of these reactions occurring by a common mechanism, involving heterolytic C–H or H–H activation via a 1,2 addition across a Co–O bond.

JUNGFRAU is a charge-integrating, two-dimensional pixel detector developed at the Paul Scherrer Institut for use at free-electron lasers, in particular SwissFEL, and synchrotron light sources. On the 10th October, the first protein crystallography experiment using the JUNGFRAU detector, was performed at the beamline X06SA (PXI) of the Swiss Light Source by the members of the Protein Crystallography and Detectors groups at PSI.

The first example of an insulating phase which is close to the superconducting phase in an iron-pnictide system has been recently observed in heavy Cu-doped NaFe_1-xCuxAs (x > 0.3). A combined study by angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations revealed that on-site Coulomb repulsion and enhanced Hund’s rule coupling are responsible for the insulating behavior. The results show that the insulating phase in NaFe_0.5Cu_0.5As resembles the situation in the parent compounds of the high-T_c cuprate superconductors.

JUNGFRAU is a charge-integrating, two-dimensional pixel detector developed at the Paul Scherrer Institut for use at free-electron lasers, in particular SwissFEL, and synchrotron light sources. On the 10th October, the first protein crystallography experiment using the JUNGFRAU detector, was performed at the beamline X06SA (PXI) of the Swiss Light Source by the members of the Protein Crystallography and Detectors groups at PSI.

One of the long-lasting unsolved problems in Nuclear Astrophysics is the so-called "Cosmological Li Problem", i.e. the large discrepancy between the primordial ⁷Li abundance predicted by models of Big Bang Nucleosynthesis and the one inferred from astronomical observation. The study of the production/destruction rates of the radioactive precursor ⁷Be is one of the clues for solving this problem.

Sahan Ranamukhaarachchi, PhD student from UBC in Vancouver, won the 2016 "Brian L. Barge Award for Excellence in Microsystems Integration" for his work on a biosensing platform with integrated hollow microneedles carried out at PSI in 2015 in collaboration with Dr. Victor Cadarso and Dr. Celestino Padeste.

Pressure-induced ordering close to a z = 1 quantum-critical point is studied in the presence of bond disorder in the quantum spin system (C₄H₁₂N₂)Cu₂(Cl_1−xBr_x)₆ (PHCX) by means of muon-spin rotation and relaxation.

On Monday October the 10th the last piece of the vacuum tube was mounted and pumped down. The about 500 m long vacuum chamber from the end of the injector to the photonics front end is now under vacuum. The only missing junction at z=119m between the already operated injector and the rest of SwissFEL will be mounted shortly before the delivery of the operation permit.

On the 6th of October the last undulator for the ARAMIS beamline was placed into the SwissFEL tunnel. Thanks to the efficiency and motivation of the different groups involved with undulator preparation, all 12 undulators were assembled, measured and installed in the tunnel between the 2nd of February 2016 and the 6th of October 2016.

Multiferroic composite materials combining ferroelectric and ferromagnetic order at room temperature have great potential for emerging applications such as four-state memories, magnetoelectric sensors, and microwave devices.

The kinetics involved in novel ambient-temperature mechanism for the catalytic oxidation of carbon monoxide by oxygen over a Pt/Al2O3 catalyst is evaluated within a periodic redox operation paradigm using combined mass spectrometry (MS), diffuse reflectance infrared spectroscopy (DRIFTS), and time-resolved Pt L3-edge XAFS. A high-wavenumber (ca. 1690 cm-1) carbonate species are shown to be associated with a room-temperature redox process occurring in a fraction of the Pt atoms present in the catalyst.

In vortex-like spin arrangements, multiple spins can combine into emergent multipole moments. Such multipole moments have broken space-inversion and time-reversal symmetries, and can therefore exhibit linear magnetoelectric (ME) activity. Three types of such multipole moments are known: toroidal; monopole; and quadrupole moments. So far, however, the ME activity of these multipole moments has only been established experimentally for the toroidal moment.

Topologically stabilized spin configurations like helices in the form of planar domain walls (DWs) or vortex-like structures with magnetic functionalities are more often a theoretical prediction rather than experimental realization. In this paper we report on the exchange coupling and helical phase characteristics within Dy-Fe multilayers. The magnetic hysteresis loops with temperature show an exchange bias field of around 1.0 kOe at 10 K.

Researcher at PSI (NES/LRT) have brought modern infrared technologies into their large thermal-hydraulic facility, called LINX, to obtain insights into condensation/evaporation process occurring under thermodynamic conditions resembling those of a nuclear power plant containment during a severe accident scenario. In such a scenario, condensation is of prime importance to control the thermodynamic state of the containment. It affects the pressure history, the overall gas (steam, hydrogen) and fission product distribution within this last barrier. Better understanding of these phenomena under accident conditions is essential to properly predict the accident evolution.

The second Chinese space laboratory satellite Tian Gong 2 was successfully launched from the Jiuquan Satellite Launch Center on September 15th, 2016 at 22:04 BTC (UTC+8h). Among more than ten instruments onboard it also brought to space the only non-Chinese experiment POLAR - the hard X-ray polarimeter.

Environmentally friendly energy conversion devices such as fuel cells are becoming more and more attractive. However, major impediments to large-scale application still arise on the material side, related to the cost and poor performance of the cathode catalyst. State-of-the-art electrocatalysts are all Pt-based materials, suffering from poor electrochemical oxygen reduction kinetics.

Skyrmions, topologically protected nanometric spin vortices, are being investigated extensively in various magnets. Among them, many structurally chiral cubic magnets host the triangular-lattice skyrmion crystal (SkX) as the thermo- dynamic equilibrium state. However, this state exists only in a narrow temperature and magnetic-field region just below the magnetic transition temperature T_c, while a helical or conical magnetic state prevails at lower temperatures.

Delayed fat digestion might help to fight obesity. Fat digestion begins in the stomach by adsorption of gastric lipases to oil/water interfaces. In this study we show how biopolymer covered interfaces can act as a physical barrier for recombinant dog gastric lipase (rDGL) adsorption and thus gastric lipolysis.