The negative muonium ion Mu-μ+e-e- has been produced by double electron pickup as a beam of positive muons passes through a foil. A clean signal was detected by electrostatically accelerating and analyzing the ions in a magnetic time-of-flight spectrometer. The Mu- beam at the focal plane of our spectrometer had an intensity 1.4×10-5 times that of the incident μ+ beam or 2 s-1, which corresponds to a Mu-/μ+ conversion probability of 0.5×10-4 at the foil in agreement with the calculated value. The kinetic energies of Mu- at the foil are less than several keV as expected.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics