A new half-life measurement of the long-lived fission product 126Sn

The half-life of the long-lived fission product 126Sn has been determined through a specific activity measurement to be (2.07±0.21).105 a. The measurement was performed with 126Sn material extracted from spent fuel rods of a nuclear power reactor. The activity concentration in this material was measured to be 4.97±0.15 Bq 126Sn/mg Sn. The half-life was determined by combining this activity concentration with the isotopic abundance of 126Sn/Sn=(9.23±0.87).10-6. P.Gartenmann et al., this issue, preeceeding paper. The latter was measured by accelerator mass spectrometry (AMS) aand is reported in an adjacent paper. This is the first direct measurement of the half-life of 126Sn, which previously had been estimated to be ∝105 years. (orig.)