Decreases in quality factor of fourth sound in superfluid {sup 3}He caused by {sup 4}He coverage of boundary surfaces
The authors measured the decrease of {sup 3}He fourth sound quality factor in packed 3, 1 and 0.3 micron powders and in sintered silver powder when the surfaces are coated with {sup 4}He. The decrease in Q results from the increase in specularity (S) and slippage of normal fluid at the wall surfaces. The authors deduce S from Q data. S does not change up to about 1.5 layers of {sup 4}He, but beyond this coverages S increases rapidly and becomes unity near 3 layer coverage. As S increases, the measured effective superfluid fraction increases. When the {sup 3}He fluid pressure is increased to greater than some pressure depending on powder, the Q and the superfluid fraction return to the pure {sup 3}He values. Qualitative features are similar to Thole and Parpia except that only very small, if any, hysteresis is observed in the authors pressure change data.
- OSTI ID:
- 243894
- Report Number(s):
- CONF-9304297--; CNN: Grant DMR 9204049
- Journal Information:
- Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 2 Vol. 38; ISSN BAPSA6; ISSN 0003-0503
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effect of [sup 4]He on the surface scattering of [sup 3]He
The effect of [sup 4]He on the surface scattering of [sup 3]He