Measurement of theCs135half-life with accelerator mass spectrometry and inductively coupled plasma mass spectrometry

The isotope $^{135}\mathrm{Cs}$ is quoted as having a half-life of 2.3 Myr. However, there are three published values ranging from 1.8 to 3 Myr. This research reviews previous measurements and reports a new measurement of the half-life using newly developed accelerator mass spectrometry (AMS) and inductively coupled plasma mass spectrometry (ICPMS) techniques along with $\ensuremath{\beta}$ and $\ensuremath{\gamma}$ radiometric analysis. The half-life was determined to be $(1.6\ifmmode\pm\else\textpm\fi{}0.6)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ yr by AMS and $(1.3\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ yr by ICPMS with 95% confidence. The two values agree with each other but differ from the accepted value by $\ensuremath{\sim}40%$.