Influence of the liquid helium meniscus on neutron reflectometry data

• Veröffentlicht in: Физика низких температур
• Datum: 2016
• Hauptverfasser: Kinane, C.J., Kirichek, O., Charlton, T.R., McClintock, P.V.E.
• Format: Artikel
• Sprache: Englisch
• Veröffentlicht: Фізико-технічний інститут низьких температур ім. Б.І. Вєркіна НАН України 2016
• Schlagworte: Морфология и свойства наноструктур
• Online Zugang: https://nasplib.isofts.kiev.ua/handle/123456789/128468
• Назва журналу: Digital Library of Periodicals of National Academy of Sciences of Ukraine
• Zitieren: Influence of the liquid helium meniscus on neutron reflectometry data / C.J. Kinane, O. Kirichek, T.R. Charlton,P.V.E. McClintock // Физика низких температур. — 2016. — Т. 42, № 2. — С. 202–206. — Бібліогр.: 24 назв. — англ.

Neutron reflectometry offers a unique opportunity for the direct observation of nanostratification in ³He–⁴He
 mixtures in the ultra-low temperature limit. Unfortunately the results of recent experiments could not be wellmodelled
 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 minimizing the meniscus distortion
 effect are discussed.