A new measurement of the 122Sb half-life

Following significant discrepancies observed when decay-correcting Sb-122 gamma-peak count rates to a reference time, we looked at the literature supporting the presently recommended 2.7238(2) d (1 sigma) Sb-122 half-life value as the source of these discrepancies. Investigation revealed that the value was derived from an inconsistent dataset and was published without reporting details of the experiment nor the uncertainty budget. In this work we performed a new measurement of the Sb-122 half-life by measuring the Sb-122 decay of neutron-activated antimony samples using state-of-the-art gamma-detection systems characterized in terms of efficiency drift and random pulse pile-up. The measurement was carried out in two different laboratories with the same method. The resulting 2.69454(39) d and 2.69388(30) d (1 sigma) Sb-122 half-life values are in agreement at the evaluated 10(-4) relative combined standard uncertainty level but are significantly lower (1.07% and 1.10% lower, respectively) than the preexisting recommended value.

Automated summary

Significant discrepancies were observed when decay-correcting Sb-122 gamma-peak count rates to a reference time, leading to a new measurement of the Sb-122 half-life value. The resulting values were lower than the preexisting recommended value, highlighting the need for further research and verification in this area.