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 a al., 2013) using the in-flight mass separator MARA at the University of Jyvaskyla. The Sm-152(S-32,4n)Pt-180 reaction was used to populate excited states in Pt-180. 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 gamma 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 gamma-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 gamma-ray techniques. The charge plunger technique is a complementary approach to lifetime measurements of excited states that depopulate through both gamma-ray emission and internal conversion. In cases where it is not possible to detect Doppler-shifted gamma rays, for example, in heavy nuclei where internal conversion dominates, it may well be the only feasible lifetime analysis approach