Measurement of muonium emission from silica aerogel

TL;DR

This study reports the observation and analysis of muonium atoms emitted from silica aerogel into vacuum, characterizing their emission properties and diffusion behavior across various densities.

Contribution

First measurement of muonium emission from silica aerogel into vacuum, with detailed analysis of diffusion characteristics and emission yields across different densities.

Findings

Muonium emission observed from silica aerogel.

Diffusion process parameters deduced from emission yields.

Decay time spectra consistent with diffusion model.

Abstract

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, 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.