Time-of-flight modulated intensity small-angle neutron scattering measurement of the self-diffusion constant of water

Journal article (2021)

Authors

Stephen J. Kuhn Indiana University - Purdue University
Niels Geerits Technische Universität Wien
C. Franz Technische Universität München
J. Plomp RID/TS/Instrumenten groep
Robert M. Dalgliesh ISIS Neutron and Muon Source
S.R. Parnell RID/TS/Instrumenten groep
Research Group
RID/TS/Instrumenten groep
Copyright: © 2021 Stephen J. Kuhn, Niels Geerits, Christian Franz, J. Plomp, Robert M. Dalgliesh, S.R. Parnell
DOI
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https://doi.org/10.1107/S1600576721002612
Water Neutron scattering Self-diffusion Neutron spin echo MI-SANS Modulated intensity small-angle neutron scattering
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Published Date

2021

Language

English

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Research Group

RID/TS/Instrumenten groep

Abstract

The modulated intensity by zero effort small-angle neutron scattering (MI-SANS) technique is used to measure scattering with a high energy resolution on samples normally ill-suited for neutron resonance spin echo. The self-diffusion constant of water is measured over a q-t range of 0.01-0.2Å-1 and 70-500ps. In addition to demonstrating the methodology of using time-of-flight MI-SANS instruments to observe diffusion in liquids, the results support previous measurements on water performed with different methods. This polarized neutron technique simultaneously measures the intermediate scattering function for a wide range of time and length scales. Two radio frequency flippers were used in a spin-echo setup with a 100kHz frequency difference in order to create a high-resolution time measurement. The results are compared with self-diffusion measurements made by other techniques and the general applicability of MI-SANS at a pulsed source is assessed.