The Half-Lives of 84zr and 85Zr

The half-lives of 84Zr and 85Zr were determined by periodic chemical isolation and yield determination of the respective yttrium daughters from chemically purified zirconium isolated from zirconium targets irradiated with 400 MeV protons. The half-life of 84Zr was found to be 5·0±0·5 min, in serious disagreement with the value previously reported. The half-life of 85Zr was found to be 6·0±1·0 min in good agreement with the literature value.