Acoustic Resonances in Helium Fluids Excited by Quartz Tuning Forks
Ordinary quartz tuning fork resonators, operated at about 30 or 200 kHz frequency, couple to acoustic first and second sound resonances in helium fluids under certain conditions. We have studied acoustic resonances in supercritical 4He, normal and superfluid 4He, and in isotopic mixtures of helium. Suggestive temperature, pressure, and concentration dependences are given. Furthermore, we propose a thermometric reference point device based on second sound resonances in helium mixtures, and indicate possible differences in the nature of second sound resonances in superfluid 4He and helium mixtures.
KeywordsQuartz tuning fork Normal 4He Superfluid 4He Helium mixtures First sound Second sound
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- 9.E. Pentti, J. Rysti, A. Salmela, A. Sebedash, J. Tuoriniemi, Helsinki University of Technology, Report TKK-KYL-020 (2009) Google Scholar