Towards a re-determination of the 42 Ar half-life

We report on a new measurement of the half-life of 42 Ar by following its decay over a time period of more than 13 years using γ-ray spectrometry. The obtained value of (39.5 ± 3.6) y confirms the only other, previously measured value of (33 ± 2) y. However, since partial outgassing of the accumulated Ar from the sample cannot be excluded, this value should be understood as a lower limit. The sample has now been stored in a gas-tight quartz ampoule to enable further measurements excluding the outgas effect in order to confirm our finding.