This work describes several experiments which examine the properties of $\sp4$He adsorbed on the porous substrate Nuclepore. Adsorption isotherm measurements are made with a capacitive technique on four sizes of Nuclepore filter. These measurements are compared to theories for adsorption, and yield pore sizes for the Nuclepore. Capillary condensation, which occurs in the pores of the Nuclepore at high coverages, is studied using both the capacitive adsorption technique and measurements of the third sound velocity on Nuclepore. These measurements are analyzed using two different theories and also yield pore sizes for the Nuclepore. Third sound attenuation is studied using a third sound resonator. The Kosterlitz-Thouless superfluid transition of $\sp4$He films adsorbed in a cylindrical geometry is examined with third sound propagation on Nuclepore. Pulsed third sound and third sound resonance techniques are employed; the third sound resonator enables frequency effects in the superfluid transition to be examined and compared to theoretical predictions for $\sp4$He films adsorbed in a single cylinder. The experiment gives an upper bound on the ratio of the pore size of the Nuclepore to the size of a vortex in the $\sp4$He film.
| Identifer | oai:union.ndltd.org:UMASS/oai:scholarworks.umass.edu:dissertations-7739 |
| Date | 01 January 1990 |
| Creators | Godshalk, Kimberly Marie |
| Publisher | ScholarWorks@UMass Amherst |
| Source Sets | University of Massachusetts, Amherst |
| Language | English |
| Detected Language | English |
| Type | text |
| Source | Doctoral Dissertations Available from Proquest |
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