Half-life determination of 215At and 221Ra with high-purity radioactive ion beams.

At CERN-ISOLDE, high-purity radioactive ion beams of 219Fr and 221RaF were investigated with α -decay spectroscopy at the CRIS and ASET experiments in the course of three different experimental campaigns. The half-life of 215At, α -decay daughter of 219Fr, is measured to be 36.3(3)[9] μ s , and that of 221Ra was determined to be 26.2(1)[6] s, both of which are well in line with the trends in this region of the nuclear landscape but at odds with some of the reported literature. [ABSTRACT FROM AUTHOR]