Longitudinal modulation of electron-cooled 12 C 6 + and 16 O 8 + ion beams at heavy ion storage ring CSRe

Highlights: • The individual lifetimes and numbers of the ${}^{12}{C}^{6+}$ and ${}^{16}{O}^{8+}$ ions were measured. • An enhancement of the Schottky noise signals was observed for rf-bunched ion beams. • A broadly longitudinal manipulation of the ion beams was realized. The longitudinal dynamics of electron-cooled and radio-frequency (RF)-bunched ${}^{12}{C}^{6+}$ and ${}^{16}{O}^{8+}$ ion beams have been investigated at a heavy-ion experimental cooler storage ring CSRe. An rf-buncher was employed to longitudinally modulate the ion beams. A new resonant Schottky pick-up was applied to monitor the intensities and longitudinal dynamics of stored and electron-cooled ion beams. Using electron-cooling, the separated Schottky noise signals of the ${}^{12}{C}^{6+}$ and ${}^{16}{O}^{8+}$ ions were clearly observed in the Schottky spectrum. The storage times and the particle numbers of both ion beams were measured by Schottky noise, which demonstrated the ability to perform Schottky mass spectrometry measurements and also the measurement of highly charged ions at the CSRe. In addition, an enhancement of the Schottky noise signals was observed for rf-bunched ion beams, which could be used to diagnose the intensity ion beams at storage rings. Finally, a broadly longitudinal manipulation of the ion beams by scanning the bunching frequency was realized. The investigation of electron–ion recombination experiment at ultra-low collision energies by scanning the bunching frequency of the ion beams at the storage ring CSRe is proposed.