Thermal acoustic oscillations in current leads cooled with supercritical helium

Observations are reported of pressure oscillations in model current leads cooled with supercritical helium. The oscillations are characterized and regions of the independent parameters in which the oscillations occurred are given. Different behavior depending on the design of each lead is noted. The effects of the thermodynamic state of the helium and the hydraulic diameter of each lead are in agreement with the theoretical predictions for simple tubes.