Toward the josephson effect in superfluid helium: How to make 20 nm holes in a 10 nm thick membrane
- 19 Downloads
It was found by electron microscope study that 20 nm diameter holes can be formed in a 10 nm thick self-supported nitrocellulose membrane covered on one side with an island gold film if exposed to the nuclear fragments from a radioactive source. The process of hole formation is a kind of Coulomb explosion. Due to its large atomic number, gold plays a role of an effective source of secondary electrons. However, if the gold thickness is increased, the higher electrical conductivity of the gold film prevents hole formation. This work was initiated in relation to the problem of the Josephson effect in superfluid helium. Our estimates show that there should be a measurable coherent effect for4He flow through our membrane with many holes for a temperature close to Tλ, when the coherence length is of order of the hole dimensions.
KeywordsVortex Critical Velocity Gold Film Gold Cluster Hole Formation
Unable to display preview. Download preview PDF.
- 4.R. E. Packard and J. C. Davis,Phys. B 194–196, 315 (1994).Google Scholar
- 5.J. Steinhaueret al., Phys. B 194–176, 767 (1994).Google Scholar
- 8.R.E. Fleisher, P.B. Price, and R.M. Walker, Univ. of California, Berkeley (1975).Google Scholar
- 10.I. V. Vorob'eva Ya. E. Geguzin, and V. E. Monastyrenko,Sov. Phys. Solid State 28, 88 (1986).Google Scholar
- 11.I. V. Vorob'eva Ya. E. Geguzin, V. E. Monastyrenko, and E. A. Ter-Ovanes'yanSov. Phys. Solid State 29, 1947 (1987).Google Scholar
- 12.E. A. Ter-Ovanes'yan, private communication.Google Scholar