Hydrogen in the submillikelvin regime: Sticking probability on superfluidHe4

Abstract

We have measured the sticking probability of atomic hydrogen on a superfluid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ surface for atom energies between 100 μK 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×${10}^{13}$ ${\mathrm{cm}}^{\mathrm{-}3}$ at a temperature of 100 μK.