Torsional Oscillator For The Study Of Helium Three In Confined Geometries

Abstract

We have constructed a torsional oscillator for the study of the 3 He liquid in confined geometries by lithographically patterning a silicon wafer and anodically bonding it to a glass wafers. The liquid helium has been constrained to an annular cavity with diameter 1cm and height 640nm. The inertia of the normal fluid has been observed to be partially coupled to the oscillator at 160mK and to completely decouple below 100mK. The decoupling is attributed to the specular scattering of the quasiparticles from the smooth surfaces of the cell. An analysis of the surface topographies has been performed and comparison to a related experiment by Casey et. al. has been done.