Kapitza Resistance at a Solid Helium-Copper Interface under Heavy Thermal Loads

Summary

Results were presented from three sets of measurements of the heat conduction between solid helium and a cold copper conductor in the 0.45 to 1.5K temperature range. The heat flux through the boundary could be described satisfactorily by Q = A(T ⁴_He - T ⁴_Cu ), with the parameter A weakly dependent on the temperature. That is, the temperature dependence of the Kapitza resistance R_K = (1/4AT³) is close to the cubic dependence predicted by the acoustic detuning theory. However, the magnitude of R_K is one to two orders smaller than that which is predicted and, in contrast with that theory, it does not depend on the density or sound velocity in He.