Abstract

J. Low Temp. Physics (2003) Submitted to Proc. QFS 2003.

A Slab of Liquid Helium-4 with Two Free Surfaces

C.D.H. Williams and A.F.G. Wyatt

School of Physics, University of Exeter, Exeter, EX4 4QL (UK).

(Submitted July 2003 )

We describe a method of creating a freely suspended 'slab' of superfluid helium-II by using a dense array of 51μm diameter parallel cylindrical holes in a glass disc of it 190μm thickness. By adjusting the chemical potential in the cell, the holes could be made to fill with liquid, and the surface-curvature controlled. We have measured the transmission of atom beams, generated by a thin-film heater and detected with a sensitive bolometer, through this slab at low temperature. The results show that R⁺-rotons can undergo total internal reflection at the free liquid surfaces and confirm that that the dominant transmission channel is atom--R⁺-roton--atom with a maximum probability p ~ 0.15 for 5 K atoms.

Keywords: liquid helium, surfaces, quantum evaporation, quantum evaporation.
Preprint: CW030701-1.pdf