Mar 20 – 23, 2023
Campus Garching
Europe/Berlin timezone

New opportunities for liquid neutron spectroscopy at ISIS

Mar 20, 2023, 2:30 PM
SCC/3-Venus - Venus (Galileo)

SCC/3-Venus - Venus


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Talk (25 + 5 min) Glasses and Liquids Glasses & Liquids


Ross Stewart (ISIS Neutron and Muon Source, UK)


Quasi-elastic neutron spectroscopy of liquids is in common usage at the ISIS Neutron and Muon Source, UK, to examine incoherent (non-propagating) dynamical properties, such as diffusion constants and local internal molecular modes. However, it is much more difficult to measure coherent excitations in liquids with neutrons due to their kinematical constraints - namely the rather limited range of excitation energies at low momentum transfers, where the coherent liquid modes must be measured.

As a result, coherent liquid spectroscopy is most commonly attempted using inelastic X-ray scattering. In principle, however, neutron spectroscopy should be able to provide much better data than IXS, since the energy resolution is generally much better, and the line-shape is a well-behaved Gaussian function rather than a Lorentzian. We will present recent data taken on the LET and MERLIN direct geometry neutron time-of-flight spectrometers on propagating excitation modes in liquids, including measurements under pressure.

We will also present an instrument concept called BRILL, which is a recently-proposed direct geometry neutron time-of-flight spectrometer at ISIS, dedicated to the measurement of low-momentum transfer propagating excitations.

Primary authors

Dr David Voneshen (ISIS Neutron and Muon Source, STFC, UK) Ross Stewart (ISIS Neutron and Muon Source, UK)


Dr Russell Ewings (ISIS Neutron and Muon Source, STFC, UK)

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