Sprecher
Beschreibung
We report on the first laser excitation of the ground-state hyperfine transition in lithium-like
208-Bi80+. The experiment was performed at the ESR, in May 2025. Detection of the transition
was enabled through a new measurement scheme that combines laser excitation with dielectronic
recombination (DR). In this approach, the electron cooler is set to a voltage that leads to the DR
process predominantly from the upper hyperfine state. Resonant laser driving of the transition to
the upper state thus leads to an enhancement of the DR recombination rate detected with particle
detectors behind the electron cooler.
This technique has been successfully demonstrated for the first time using the radioactive isotope
208Bi in the lithium-like charge state, a species that is inherently difficult to produce, decelerate,
and store at the required energies in the ESR. These results establish the feasibility of the method
and pave the way for precision measurements during the next beam time, which has already been
approved by the GPAC (Proposal G-24-00290). This research was funded by BMFTR, Contract
numbers 05P24RD5, 05P21RGFA1 and 5P24RG2.
