Paul Trapping of Radioactive ⁶He⁺ Ions and Direct Observation of Their β Decay

We demonstrate that abundant quantities of short-lived β unstable ions can be trapped in a novel transparent Paul trap and that their decay products can directly be detected in coincidence. Low energy ⁶He⁺ (807 ms half-life) ions were extracted from the SPIRAL source at GANIL, then decelerated, cooled, and bunched by means of the buffer gas cooling technique. More than 10⁸ ions have been stored over a measuring period of six days, and about 10⁵ decay coincidences between the beta particles and the ⁶Li⁺⁺ recoiling ions have been recorded. The technique can be extended to other short-lived species, opening new possibilities for trap assisted decay experiments.