Lifetime Measurement of the Metastable 23 p 0 State in Helium-like 197au

The determination of atomic lifetimes offers the possibility to investigate various aspects of the atomic structure. In the case of helium-like 197Au with nuclear spin 3/2, due to hyperfine-quenching, one can determine the 23P0–23P1 fine-structure splitting from the lifetime measurement of the metastable 23P0 state. This lifetime has been measured at the GSI accelerator facility with the beam-foil time-of-flight technique and has taken advantage of particle-X-ray coincidences using a charge state spectrometer in conjuction with a newly developed CVD-diamond particle detector. A preliminary analysis has given a value of 22.45±0.66 ps for the lifetime of the 23P0 state in helium-like gold. This is in good agreement with theoretical predictions.