Measurements of the Second-Sound Damping in DiluteHe3-He4Solutions

Results for the second-sound damping in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ solutions with ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ molar concentrations of 0.001, 0.003, and 0.005 are presented for frequencies of 2, 3, and 5 kHz and in the temperature range 40 mK to 1 K. The damping is nonhydrodynamic and shows a peak near $T=0\mathrm{} 4$ K, which increases with decreasing concentration and also with increasing pressure.