Influence of the liquid helium meniscus on neutron reflectometry data

Kinane, C. J. and Kirichek, O. and Charlton, T. R. and McClintock, Peter Vaughan Elsmere (2016) Influence of the liquid helium meniscus on neutron reflectometry data. Low Temperature Physics, 42 (2). pp. 202-206. ISSN 1063-777X

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Abstract

Neutron reflectometry offers a unique opportunity for the direct observation of nano-stratification in 3He-4He mixtures in the ultra-low temperature limit. Unfortunately the results of recent experiments could not be well-modelled on account of a seemingly anomalous variation of reflectivity with momentum transfer. We now hypothesize that this effect is attributable to an optical distortion caused by the liquid’s meniscus near the container wall. The validity of this idea is tested and confirmed through a subsidiary experiment on a D2O sample, showing that the meniscus can significantly distort results if the beam size in the horizontal plane is comparable with, or bigger than, the diameter of the container. The meniscus problem can be eliminated if the beam size is substantially smaller than the diameter of the container, such that reflection takes place only from the flat region of the liquid surface thus excluding the meniscus tails. Practical measures for minimising the meniscus distortion effect are discussed.

Item Type: Journal Article
Journal or Publication Title: Low Temperature Physics
Additional Information: C 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/)
Uncontrolled Keywords: /dk/atira/pure/subjectarea/asjc/3100
Subjects:
Departments: Faculty of Science and Technology > Physics
ID Code: 76956
Deposited By: ep_importer_pure
Deposited On: 01 Dec 2015 10:46
Refereed?: Yes
Published?: Published
Last Modified: 15 Nov 2019 02:27
URI: https://eprints.lancs.ac.uk/id/eprint/76956

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