A charge plunger device to measure the lifetimes of excited nuclear states where transitions are dominated by internal conversion.

A charge plunger device has been commissioned based on the DPUNS plunger (Taylor et al., 2013) using the in-flight mass separator MARA at the University of Jyväskylä. The 152 Sm (32 S ,4 n)180 Pt reaction was used to populate excited states in 180 Pt. A lifetime measurement of the 2 1 + state was performed by applying the charge plunger technique, which relies on the detection of the charge state-distribution of recoils rather than the detection of the emitted γ rays. This state was a good candidate to test the charge plunger technique as it has a known lifetime and depopulates through a converted transition that competes strongly with γ -ray emission. The lifetime of the 2 1 + state was measured to be 480 (10) ps , which is consistent with previously reported lifetimes that relied on the standard γ -ray techniques. The charge plunger technique is a complementary approach to lifetime measurements of excited states that depopulate through both γ -ray emission and internal conversion. In cases where it is not possible to detect Doppler-shifted γ rays, for example, in heavy nuclei where internal conversion dominates, it may well be the only feasible lifetime analysis approach. [ABSTRACT FROM AUTHOR]