Measurement of muonium emission from silica aerogel

Abstract

Emission of muonium ($\hat{I}{¼}^{+}{e}^{-}$) 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, 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.

11 pages, 5 figures, submitted to PTEP