Quartz Resonators For Penning Traps Toward Mass Spectrometry On The Heaviest Ions

We report on cyclotron frequency measurements on trapped (206,207)Pb(+)ions by means of the non-destructive Fourier-transform ion-cyclotron-resonance technique at room temperature. In a proof-of-principle experiment using a quartz crystal instead of a coil as a resonator, we have alternately carried out cyclotron frequency measurements for Pb-206(+) and (207)Pb(+)with the sideband coupling method to obtain 21 cyclotron-frequency ratios with a statistical uncertainty of 6 x 10(-7). The mean frequency ratioR over bar deviates by about 2 sigma from the value deduced from the masses reported in the latest Atomic Mass Evaluation. We anticipate that this shift is due to the ion-ion interaction between the simultaneously trapped ions (approximate to 100) and will decrease to a negligible level once we reach single-ion sensitivity. The compactness of such a crystal makes this approach promising for direct Penning-trap mass measurements on heavy and superheavy elements.