Measurements of the Kapitza conductance between metals and liquid helium II by the transmission of second sound

Abstract

Measurements have been made in the temperature range 1.0-2.0K of the alternating heat current transmitted through tin metal foils separating two second sound resonators. The experimental arrangement and analysis are described in some detail. The values of the Kapitza conductance obtained in this way of copper, and of indium, lead and tin, are comparable to those obtained using the usual steady state method, although the temperature dependence is always significantly higher: about T⁴. In general, the total foil conductance in the superconducting state is larger than in the normal state and it is believed that this is due to size effects arising from the long phonon mean free paths. An interpretation of these results suggests that the effective phonon transmission coefficient from lead to helium is greater than or approximately equal to 0.67.