Publications de Felix Groitl | EPFL Graph Search

Commissioning of the novel Continuous Angle Multi-energy Analysis spectrometer at the Paul Scherrer Institut

Henrik Moodysson Rønnow, Felix Groitl, Jakob Lass

We report on the commissioning results of the cold neutron multiplexing secondary spectrometer CAMEA (Continuous Angle Multi -Energy Analysis) at the Swiss Spallation Neutron Source at the Paul Scherrer Institut, Switzerland. CAMEA is optimized for efficie ...

AIP Publishing2023

Direct bonded HOPG - Analyzer support without background source

Henrik Moodysson Rønnow, Felix Groitl

2018

Prototype of the novel CAMEA concept-A backend for neutron spectrometers

Henrik Moodysson Rønnow, Paul Gregory Freeman, Felix Groitl, Jakob Lass

2018

Generalized resolution matrix for neutron spin-echo three-axis spectrometers

Thomas Keller, Felix Groitl

This article describes the energy resolution of spin-echo three-axis spectrometers (SE-TASs) by a compact matrix formalism. SE-TASs allow one to measure the line widths of elementary excitations in crystals, such as phonons and magnons, with an energy reso ...

INT UNION CRYSTALLOGRAPHY2018

Spin excitations in the skyrmion host Cu2OSeO3

Arnaud Magrez, Henrik Moodysson Rønnow, Ivica Zivkovic, Jonathan White, Peter Babkevich, Ping Huang, Felix Groitl, Gregory Scott Tucker

We have used inelastic neutron scattering to measure the magnetic excitation spectrum along the high-symmetry directions of the first Brillouin zone of the magnetic skyrmion hosting compound Cu2OSeO3. The majority of our scattering data are consistent with ...

Amer Physical Soc2016

Time-dependent correlations in quantum magnets at finite temperature

Thomas Keller, Felix Groitl

In this Rapid Communication we investigate the time dependence of the gap mode of copper nitrate at various temperatures. We combine state-of-the-art theoretical calculations with high precision neutron resonance spin-echo measurements to understand the an ...

Amer Physical Soc2016

Anomalous thermal decoherence in a quantum magnet measured with neutron spin echo spectroscopy

Thomas Keller, Felix Groitl

The effect of temperature dependent asymmetric line broadening is investigated in Cu(NO3)(2)center dot 2.5D(2)O, a model material for a one-dimensional bond alternating Heisenberg chain, using the high resolution neutron-resonance spin echo (NRSE) techniqu ...

Amer Physical Soc2016

A combined radial collimator and cooled beryllium filter for neutron scattering

Henrik Moodysson Rønnow, Felix Groitl

A flexible, combined, radial collimator and beryllium (Be) filter have been designed and manufactured at the Paul Scherrer Institut (PSI), Switzerland. The Be is integrated in the radial collimator by placing thin Be slices between the collimator lamellas. ...

Elsevier2016

CAMEA—A novel multiplexing analyzer for neutron spectroscopy

Henrik Moodysson Rønnow, Felix Groitl, Christian Rüegg

The analyzerdetector system continuous angle multiple energy analysis will be installed on the cold-neutron triple-axis spectrometer RITA-2 at SINQ, PSI. CAMEA is optimized for efficiency in the horizontal scattering plane enabling rapid and detailed mappi ...

American Institute of Physics2016

Experimental characterization of a prototype secondary spectrometer for vertically scattering multiple energy analysis at cold-neutron triple axis spectrometers

Felix Groitl

A thorough experimental characterization of a multiplexing backend with multiple energy analysis on a cold-neutron triple axis spectrometer (cTAS) is presented. The prototype employs two angular segments (2 theta-segments) each containing five vertically s ...

Elsevier2016

Neutron Larmor diffraction investigation of the rare-earth pyrochlores R2Ti2O7 (R = Tb, Dy, Ho)

Thomas Keller, Felix Groitl

In this work, we present a neutron Larmor diffraction study of the rare-earth pyrochlores R2Ti2O7 with R = Tb, Dy, Ho. We measured the temperature dependence of the lattice parameter with precision 10(-5), between 0.5 and 300 K in each of the three compoun ...

Amer Physical Soc2016

The upgraded cold neutron triple-axis spectrometer FLEXX - enhanced capabilities by new instrumental options

Felix Groitl

The upgrade of the cold neutron triple axis spectrometer FLEXX, a work-horse instrument for inelastic neutron scattering matching the sample environment capabilities at Helmholtz-Zentrum Berlin, has been successfully accomplished. Experiments confirmed an ...

E D P Sciences2015

Luttinger liquid behavior in the alternating spin-chain system copper nitrate

Felix Groitl

We determine the phase diagram of copper nitrate Cu(NO3)(2)center dot 2.5D(2)O in the context of quantum phase transitions and novel states of matter. We establish this compound as an ideal candidate to study quasi-1D Luttinger liquids, 3D Bose-Einstein-Co ...

American Physical Society2015

Neutron resonance spin-echo upgrade at the three-axis spectrometer FLEXX

Thomas Keller, Felix Groitl

We describe the upgrade of the neutron resonance spin-echo setup at the cold neutron triple-axis spectrometer FLEXX at the BER II neutron source at the Helmholtz-Zentrum Berlin. The parameters of redesigned key components are discussed, including the radio ...

American Institute of Physics2015