Fluid catalytic cracking, a century old chemical conversion process utilizing porous composites of zeolite and clay, up to this day provides the majority of the world’s gasoline. Owing to harsh reaction environments and feedstock impurities the employed catalysts deactivate, necessitating their continuous fractional replacement with major refineries requiring up to 40 tons of fresh catalyst in total on a daily basis. Using a combination of ptychographic, x-ray diffraction and -fluorescence tomography researchers from PSI and ETH elucidated the structural changes behind catalyst deactivation.

In a frustrated magnet, spins are arranged in geometries that prevent the formation of conventional magnetic patterns such as ferromagnetic or anti-ferromagnetic order. Yet, the interaction between the spins can nonetheless lead to highly correlated quantum states, including exotic ones that remain not fully understood such as so-called spin ices or spin liquids. Frustrated magnets are therefore ideal materials for investigating, both theoretically and experimentally, the intricate interplay of interactions in quantum many-body systems and the phases emerging from them ...

In its orthorhombic T_d polymorph, MoTe₂ is a type-II Weyl semimetal, where the Weyl fermions emerge at the boundary between electron and hole pockets. Non-saturating magnetoresistance and superconductivity were also observed in T_d-MoTe₂. Understanding the superconductivity in T_d-MoTe₂, which was proposed to be topologically non-trivial, is of eminent interest. Here, we report high-pressure muon-spin rotation experiments probing the temperature-dependent magnetic penetration depth T_d-MoTe₂ ...

An upgrade of the Swiss Light Source, named SLS-2, will increase the brightness and coherence of synchrotron radiation in order to maintain the PSI at the forefront of x-ray science with the advent of the next generation of light sources.
The electron storage ring of the SLS will be replaced by a new one with a larger number of magnets and reduced vacuum chamber dimensions and magnet apertures. A novel type of lattice combining 84 bending magnets with longitudinal field variation and 144 bending magnets with reversed field polarity will lower the horizontal emittance by a factor of 45 compared to today, down to a value of 125 pm.rad at 2.4 GeV beam energy and 400 mA stored current (with 10 pm.rad vertical emittance and 50 ps FWHM bunch length). The existing injector complex will be re-used.
A conceptual design report has been reviewed by an international committee in September. A proposal will be submitted to the Swiss National Science Foundation by the end of the year to place SLS-2 on the research infrastructures roadmap in the period 2021-24. First light from SLS-2 is expected for the fall of 2024.

The new neutron single-crystal diffractometer Zebra, which has replaced the TriCS instrument, is in user operation since May 2017. It allows crystallographic and parametric studies (temperature, magnetic and electric fields, pressure). Zebra is designed to achieve high peak-to-background ratio. The instrument is aimed at resolving challenges emerging in systems that are available as small crystals and requiring extreme sample environments.
Metal-Organic Frameworks are typical examples of novel materials that are often only available as small single crystals and where various topologies of spin carriers can lead to remarkable properties. In Mn₅(OH)₂(C₄H₄O₄)₄, about 140 Bragg reflections were measured on ZEBRA using a sample of mass 0.35 mg, revealing a complex non-collinear antiferromagnetic structure with three independent magnetic sites.

Recently a new spin rotator has been installed in the PiM3 secondary beamline delivering spin-polarized muons to the GPS and LTF instrument. The new device features much improved characteristics compared to the 40 years old one with respect to stability, transmission and rotation angle. With its maximal operation voltage of 600kV it achieves a 65 degrees muon spin rotation leading to a 91% polarization which is now available for transverse field μSR experiments.

On November 13, 2017 16 organisations representing 19 light sources facilities across Europe gathered in Brussels to launch the LEAPS initiative and signed an agreement to strengthen their collaboration, in the presence of Robert-Jan Smits, Director General for Research and Innovation (RTD) at the European Commission, and Giorgio Rossi, Chair of the European Strategy Forum on Research Infrastructures (ESFRI).
LEAPS, the League of European Accelerator-based Photon Sources, aims to offer a step change in European cooperation, through a common vision of enabling scientific excellence solving global challenges, and boosting European competitiveness and integration. This will be achieved through a common sustainable strategy developed in coordination with all stakeholders, including national policy makers, user communities and the European Commission. The light sources that form LEAPS are all accelerators-based, producing exceptionally intense beams of X-rays, ultra-violet and infrared light. They count with a community of 24.000 direct user scientists with an extended network of 35.000 researchers, among them five Nobel Prizes.

Originally conceived in Sussex, first operated at the Institute Laue-Langevin (ILL), the neutron electric dipole moment (nEDM) spectrometer was upgraded for measurements at PSI starting with its move in 2009. On October 16th the last ultracold neutrons (UCN) were counted with this device.
Dismantling of the apparatus started immediately and only weeks later, with the great support of PSI services from Hallendienst to SU radiation protection, UCN area South is ready for assembly of the new n2EDM experiment. Data of the nEDM spectrometer resulted in more than 10 seminal publications of which four are historical upper limits for the nEDM.
The latest spectacular publication, a limit on ultra-low mass axions, is highlighted in this facility newsletter, see above.

Copyright © 2017, Paul Scherrer Institut PSI

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PSI Facility News addresses the users of the PSI large facilities and appears quarterly in English. Any feedback is highly welcome! More information. 

Contact: PSI User Office, Phone: +41-56-310-4666, Email: useroffice@psi.ch