Physica B 284 160-1 (2000)
Relative Evaporation Probabilities of 3He and 4He from the Surface of Superfluid 4He
School of Physics, University of Exeter, Exeter,
EX4 4QL (UK).
(Submitted 17 June 1999)
We report a preliminary experiment which demonstrates that 3
He atoms in Andreev states are evaporated by high-energy (E/kB
~10.2 K) phonons in a quantum evaporation process similar to that which occurs in pure 4
He. Under conditions of low 3
He coverage, high-energy phonons appear to evaporate 3
He and 4
He atoms with equal probability. However, we have not managed to detect any 3
He atoms that have been evaporated by rotons, and conclude that the probability of a roton evaporating a 3
He atom is less than 2% of the probability that it evaporates a 4
Keywords: liquid helium, surfaces, quantum evaporation, 2-D fermion systems.
Preprint: PDF (115kB)