Determination of the half-life of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msup><mml:mrow/><mml:mrow><mml:mn>37</mml:mn></mml:mrow></mml:msup></mml:mrow><mml:mi mathvariant="normal">Ar</mml:mi></mml:math>by mass spectrometry

The half-life of ${}^{37}\mathrm{Ar}$ has been determined via mass spectrometry by measuring the ratio of ${}^{37}\mathrm{Ar}$ to stable ${}^{36}\mathrm{Ar}$ as a function of time in neutron-irradiated samples of ${\mathrm{CaF}}_{2}.$ The half-life we obtain is $34.95\ifmmode\pm\else\textpm\fi{}0.08\mathrm{d}$ (95% confidence level). This result is compared to previous experiments based on radioactivity measurements.