Acoustic Damping of Quartz Tuning Forks in Normal and Superfluid $^3$He

Guénault, Tony and Haley, Richard and Kafanov, Sergey and Noble, Theo and Pickett, George and Poole, Malcolm and Schanen, Roch and Tsepelin, Viktor and Vonka, Jakub and Wilcox, Tom and Zmeev, Dmitry (2019) Acoustic Damping of Quartz Tuning Forks in Normal and Superfluid $^3$He. Physical Review B: Condensed Matter and Materials Physics, 100 (10): 104526. ISSN 1098-0121

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Abstract

We investigate the damping experienced by quartz tuning fork resonators in normal and superfluid 3He as a function of their resonance frequency from 22 kHz to 250 kHz and contrast it with the behavior of the forks in 4He. For our set of tuning forks the low frequency damping in both fluids is well described by the existing hydrodynamic models. We find that the acoustic emission becomes the dominating dissipation mechanism at resonator frequencies exceeding approximately 100 kHz. Our results show that the acoustic emission model used in 4He fluid also describes acoustic damping in superfluid 3He and normal 3He at low temperatures using same geometrical prefactor. The high temperature acoustic damping in normal 3He does not exceed prediction of this model and thus the acoustic damping of moderate frequency devices measured in 4He should be similar or smaller in 3He liquid.