Experimental investigation of cavitation in superfluidHe4

We present the results of experiments to study cavitation in liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ at negative pressures. A focused sound wave is used to generate a negative pressure in a small region of the liquid, and the cavitation is detected by light scattering. We have studied the cavitation as a function of the temperature and static pressure applied to the liquid. We are able to observe the statistical nature of the cavitation process, and to determine the nucleation barrier and the attempt frequency. The results for the attempt frequency are lower than expected for homogeneous nucleation. We discuss the possibility that the nucleation is occurring on quantized vortices. The tensile strength at constant pressure decreases slowly with increasing temperature in the range 0.8 to 1.5 K, drops rapidly as the temperature approaches the λ point, and then decreases slowly above ${\mathit{T}}_{\lambda }$.