Measurement of the lifetime and the proportion of 12C3+ ions in stored relativistic ion beams as a preparation for laser cooling experiments at the CSRe

We report on an experiment that was conducted in preparation of laser cooling experiments at the heavy-ion storage ring CSRe. The lifetimes of ion beams made up of 12C3+ and 16O4+ ions stored at an energy of 122 MeV/u in the CSRe were determined by two independent methods, firstly via a DC current transformer (DCCT) and secondly via a Schottky resonator. Using electron-cooling, the signals of the 12C3+ and 16O4+ ions could be separated and clearly observed in the Schottky spectrum. The obtained individual lifetimes of the 12C3+ and 16O4+ components were 23.6 s and 17.8 s, respectively. The proportion of 12C3+ ions in the stored ion beam was measured to be more than 70% at the beginning of the injection and increasing as a function of time. In addition to these measurements, the operation and remote control of a pulsed laser system placed directly next to the storage ring was tested in a setup similar to the one envisaged for future laser experiments.