A5009390557- X-ray Spectroscopy and Fluorescence Analysis
- Magnetic and transport properties of perovskites and related materials
- Particle physics theoretical and experimental studies
- Muon and positron interactions and applications
- Electronic and Structural Properties of Oxides
- Particle accelerators and beam dynamics
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Advanced Condensed Matter Physics
- Advanced X-ray Imaging Techniques
- Advanced Memory and Neural Computing
- Particle Accelerators and Free-Electron Lasers
- Quantum Chromodynamics and Particle Interactions
- Neutrino Physics Research
- Atomic and Molecular Physics
- Radioactive element chemistry and processing
- High-Energy Particle Collisions Research
- Electron and X-Ray Spectroscopy Techniques
- Advanced Chemical Physics Studies
- Ferroelectric and Piezoelectric Materials
- Particle Detector Development and Performance
- Catalytic Processes in Materials Science
- Calcium Carbonate Crystallization and Inhibition
- Advanced X-ray and CT Imaging
- Nuclear Physics and Applications
Paul Scherrer Institute
2008-2024
The University of Sydney
2016
Swiss Light Source
2001-2014
Lawrence Berkeley National Laboratory
2009-2014
ETH Zurich
1995-2011
SLAC National Accelerator Laboratory
2011
European Synchrotron Radiation Facility
2011
Bioengineering (Switzerland)
2011
Tecnologie Avanzate (Italy)
2009
Università degli Studi del Piemonte Orientale “Amedeo Avogadro”
2009
Transition metal oxides exhibiting a bistable resistance state are attractive for nonvolatile memory applications. The relevance of oxygen vacancies the resistance-change is investigated by X-ray fluorescence (see figure), infrared microscopy, and absorption spectroscopy using Cr-doped SrTiO3 as an example. microscopic origin switching in this class materials may be due to oxygen-vacancy drift occurring close proximity one electrodes.
The SwissFEL X-ray Free Electron Laser (XFEL) facility started construction at the Paul Scherrer Institute (Villigen, Switzerland) in 2013 and will be ready to accept its first users 2018 on Aramis hard branch. In following sections we summarize various aspects of project, including design soft branches accelerator, results performance simulations, details photon beamlines experimental stations, our commissioning results.
High precision measurements of two Zeeman hyperfine transitions in the ground state muonium a strong magnetic field have been made at LAMPF using microwave resonance spectroscopy and line narrowing technique. These determine most precise values structure interval $\ensuremath{\Delta}\ensuremath{\nu}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}4463302765(53)\mathrm{Hz}$ $(12\mathrm{ppb})$, ratio moments...
Dealumination of NH(4)-Y zeolite during steaming to 873 K was investigated with in situ, time-dependent, synchrotron radiation XRPD and situ Al K-edge XAS. Water desorption is complete at 450 K, ammonium decomposition occurs between 500 550 K. Only a small fraction Al(3+) species (5%) leaves the framework heating from 710 K; these occupy site I' inside sodalite cage. This increases up 8% first 50 min remains constant for following 70 isotherm high-temperature part cooling experiment. During...
Reaction of (CpSiMe3)3U or (CpSiMe3)3Nd with (Cp*Al)4 Cp*Ga (Cp* = C5Me5) afforded the isostructural complexes (CpSiMe3)3M−ECp* (M U, E Al (1); M Ga (2); Nd, (3); (4)). In case 1 and 2 were isolated in 39 90% yields, respectively, as crystalline solids characterized by single-crystal X-ray diffraction, variable-temperature 1H NMR spectroscopy, elemental analysis, magnetic susceptibility, UV−visible−NIR spectroscopy. 3 4, observed spectroscopy but not pure materials. Comparison equilibrium...
Soft x-ray resonant scattering at the Ni ${L}_{2,3}$ edges is used to test models of magnetic- and orbital-ordering below metal-insulator transition in ${\mathrm{NdNiO}}_{3}$. The large branching ratio ${L}_{3}$ ${L}_{2}$ intensities $(1∕2\phantom{\rule{0.3em}{0ex}}0\phantom{\rule{0.3em}{0ex}}1∕2)$ reflection observed azimuthal angle polarization dependence originates from a noncollinear magnetic structure. absence an orbital signal structure show that nickelates are materials for which...
The origin of sulfite (S4+) species in silicate glasses was evaluated using XANES at the S K-edge. Systematic investigations show that presence S4+ is an analytical artifact related to changes sulfur caused by irradiation with electron beam during EMPA or intense focused X-ray synchrotron analysis. data shown here indicate S2- and S6+ are only significant occurring synthesized under geologically relevant conditions.
We present the extension of time-resolved optical pump/x-ray absorption spectroscopy (XAS) probe experiments towards data collection at MHz repetition rates. The use a high-power picosecond laser operating an integer fraction rate storage ring allows exploitation up to two orders magnitude more x-ray photons than in previous schemes based on kHz lasers. Consequently, we demonstrate order increase signal-to-noise XAS molecular systems solution. This makes it possible investigate highly dilute...
A Johann-type spectrometer with five spherically bent crystals and a pixel detector was constructed for range of hard x-ray photon-in photon-out synchrotron techniques, covering Bragg-angle 60°–88°. The provides sub emission line width energy resolution from sub-eV to few eV precise calibration, better than 1.5 the full Bragg angles. use allows fast easy optimization signal-to-background ratio. concentration detection limit below 0.4 wt% reached at Cu Kα1 line. is designed as modular mobile...
The catalytically active phase of silica-supported palladium catalysts in the selective and non-selective hydrogenation 1-pentyne was determined using situ X-ray absorption spectroscopy at Pd K L3 edges. Upon exposure to alkyne, a carbide-like rapidly forms, which prevents hydrogen diffuse into bulk nano-sized particles. Both occur over carbided is stable under reaction conditions only partially decomposes high partial pressure. Non-selective pentane not indicative hydride formation. carbide...
We have determined the momentum ${p}_{{\ensuremath{\mu}}^{+}}$ of muons from decay ${\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\nu}}_{\ensuremath{\mu}}$ at rest, by analyzing a surface muon beam in magnetic spectrometer equipped with silicon microstrip detector. The result ${p}_{{\ensuremath{\mu}}^{+}}=(29.79200\ifmmode\pm\else\textpm\fi{}0.00011)$ MeV/c leads to squared muon-neutrino mass...
Resistivity measurements and x-ray absorption near-edge structure spectroscopy were performed on single crystals of 0.2 mol % Cr-doped $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_{3}$, which exhibit an electrical-field-induced insulator-to-conductor transition with a resistive memory effect. The electrically conducting state is shown to be metallic. insulator-to-metal accompanied by increase the Cr valence underneath anode from ${\mathrm{Cr}}^{3+}$ approximately ${\mathrm{Cr}}^{4+}$. This indicates...
We provide a status report on the development of perovskite-based transition-metal-oxide resistance-change memories. focus bipolar resistance switching observed in Cr-doped SrTiO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</inf> memory cells with dimensions ranging from bulk single crystals to CMOS integrated nanoscale devices. also discuss electronic and ionic processes during electroforming switching, as evidenced electron-parametric...
The SwissFEL Injector Test Facility operated at the Paul Scherrer Institute between 2010 and 2014, serving as a pilot plant testbed for development realization of SwissFEL, X-ray Free-Electron Laser facility under construction same institute. test consisted laser-driven rf electron gun followed by an S-band booster linac, magnetic bunch compression chicane diagnostic section including transverse deflecting cavity. It delivered bunches up to 200 pC charge 250 MeV beam energy repetition rate...
We report on the decomposition of platinum acetylacetonate (Pt(acac)2) in hydrogen induced by flash heating. The changes local Pt structure were followed high energy resolution off-resonant spectroscopy uniquely performed with sub-second time resolution. consists a two-step reduction process Pt(II) species.
Detailed resonant x-ray diffraction experiments including azimuthal angle scans were performed on $\mathrm{Nd}\mathrm{Ni}{\mathrm{O}}_{3}$ around the Ni $K$ absorption edge, allowing us to investigate electronic changes associated with metal-to-insulator transition. The influence observed reflections of charge disproportionation and asphericity electron density is evaluated. asphericity, due distortion oxygen octahedra, persists also in metallic phase, but its unrotated...
In order to probe the structure of reaction intermediates photochemical reactions a new setup for laser-initiated time-resolved X-ray absorption (XAS) measurements has been developed. With this approach arrival time each photon in respect laser pulse is measured and therefore full kinetic information obtained. All X-rays that reach detector are used measure detection efficiency method high. The newly developed optimized experiments microsecond range samples with relatively low metal...