EXPERIMENTAL INVESTIGATION OF CAVITATION IN SUPERFLUID HE-4

We present the results of experiments to study cavitation in liquid He -4 at negative pressures. A focused sound wave is used to generate a n egative pressure in a small region of the liquid, and the cavitation i s detected by light scattering. We have studied the cavitation as a fu nction of the temperature and static pressure applied to the liquid. W e are able to observe the statistical nature of the cavitation process , and to determine the nucleation barrier and the attempt frequency. T he results for the attempt frequency are lower than expected for homog eneous nucleation. We discuss the possibility that the nucleation is o ccurring on quantized vortices. The tensile strength at constant press ure decreases slowly with increasing temperature in the range 0.8 to 1 .5 K, drops rapidly as the temperature approaches the lambda point, an d then decreases slowly above T(lambda).