Helmholtz Resonances in Helium near Lambda Point

David Kasper and George Brown

University of Minnesota

Methods of Experimental Physics Spring 2012

Abstract

In liquid helium below 2.18K, two components termed the superfluid and normal fluid coexist. In our experiment we attempted to measure the temperature dependence of the relative abundance of the superfluid component of liquid helium. To this end we explored the Helmholtz resonance frequency as we varied the temperature in an experimental cell. The key characteristic of the experimental cell was the presence of filter channels which allowed for the superfluid (which had zero viscosity) to flow freely while preventing the flow of the normal fluid.