Fig. 2. ²⁰⁵Tl experiment setup and results.

a, A ²⁰⁶Pb⁶⁷⁺ beam was accelerated by the SIS-18 synchrotron and projectile fragmentation produced ²⁰⁵Tl⁸¹⁺ ions that were selected by the FRS and stored in the ESR. Copyright, GSI/FAIR. b, Ion intensity monitoring shows the accumulation and storage of ²⁰⁵Tl⁸¹⁺ ions, as well as the revelation of ²⁰⁵Pb⁸²⁺ daughter ions once the gas target is turned on. Note that the ²⁰⁵Pb⁸²⁺ intensity is scaled by 10³ so that it is visible. c, The observed ratio of ²⁰⁵Pb⁸¹⁺ to ²⁰⁵Tl⁸¹⁺ ions for 16 storage runs is shown, alongside the best fit of equation (1) (blue line). Error bars are 1σ Gaussian.