Phonons Created in Superfluid Helium by a Thin Film Gold Heater

We show that a thin film gold heater, on polished sapphire, radiates phonons into liquid helium by both the acoustic and background channels. To analyse the measured angular distributions of phonons, at a pressure of 24 bar, we derive an expression for the phonon flux incident on a detector for a ge...

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Bibliographic Details
Published in:	Journal of low temperature physics Vol. 157; no. 5-6; pp. 509 - 526
Main Authors:	Adamenko, I. N., Nemchenko, K. E., Slipko, V. A., Wyatt, A. F. G.
Format:	Journal Article
Language:	English
Published:	Boston Springer US 01-12-2009
Subjects:	Channels Characterization and Evaluation of Materials Condensed Matter Physics Detectors Flux Gold Heaters Heating equipment Liquid helium Magnetic Materials Magnetism Phonons Physics Physics and Astronomy Thin films Kapitza conductance Superfluid helium Phonons
Online Access:	Get full text
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Summary:	We show that a thin film gold heater, on polished sapphire, radiates phonons into liquid helium by both the acoustic and background channels. To analyse the measured angular distributions of phonons, at a pressure of 24 bar, we derive an expression for the phonon flux incident on a detector for a general spatial arrangement of heater and detector, when the phonons travel ballistically. We then develop an expression for the particular geometry of the experiments. We find that most of the energy flux, from the heater to the liquid helium, is transmitted by the background channel and this fraction increases with heater power. We discuss the implications for the Kapitza conductance problem.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0022-2291 1573-7357
DOI:	10.1007/s10909-009-0011-z