Laser-Fluorescence Mass Spectroscopy

Measurements of ion cyclotron-resonance frequencies in a Penning trap, by a laser fluorescence technique, are described. This technique has been applied to indirect measurements of the proton-to-electron mass ratio and the ^9Be^+ electron g₉ factor. It is found that m₏{m₄}=1836. 15238 (62) (0. 34 ppm) and g₉ (^9Be^+) =2. 00226206 (42) (0. 21 ppm). Ultimately, ion cyclotron-resonance accuracies near 1 part in 10^13 should be possible.