Measurement of muonium emission from silica aerogel

Emission of muonium (mu(+)e(-)) atoms from silica aerogel into vacuum was observed. Characteristics of muonium emission were established from silica aerogel samples with densities in the range from 29 mg cm(-3) to 178 mg cm(-3). Spectra of muonium decay times correlated with distances from the aerogel surfaces, which are sensitive to the speed distributions, and follow general features expected from a diffusion process, while small deviations from a simple room-temperature thermal diffusion model are identified. The parameters of the diffusion process are deduced from the observed yields.