Physical Review Letters
Hydrogen in the submillikelvin regime: Sticking probability on superfluid He4
John M. Doyle, Jon C. Sandberg, Ite A. Yu, Claudio Lenz Cesar, Daniel Kleppner, Thomas J. Greytak
Abstract
We have measured the sticking probability of atomic hydrogen on a superfluid $^{4}\mathrm{He}$ surface for atom energies between 100 \ensuremath{\mu}K and 1 mK. The sticking probability shows little variation with energy over this interval, and is close to the value 0.2. The studies were carried out using a magnetic trap that produced a density of 8\ifmmode\times\else\texttimes\fi{}${10}^{13}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}3}$ at a temperature of 100 \ensuremath{\mu}K.