Half-life of Ti 44

The half-life of $^{44}\mathrm{Ti}$ has been measured to be ${T}_{\frac{1}{2}}=54.2\ifmmode\pm\else\textpm\fi{}2.1$ yr, somewhat higher than previously published values of 46.4\ifmmode\pm\else\textpm\fi{}1.7 and 48.2\ifmmode\pm\else\textpm\fi{}0.9 yr. The present value was obtained from the specific activity and the radioisotope concentration of several Ti${\mathrm{O}}_{2}$ samples, each spiked with a $^{44}\mathrm{Ti}$ activity of about 1.2 \ensuremath{\mu}Ci. The specific activity was measured via the 1157 keV $\ensuremath{\gamma}$ line from the decay of the $^{44}\mathrm{Sc}$ daughter. $^{44}\mathrm{Ti}$/Ti concentrations were measured with the Argonne FN tandem accelerator in conjunction with an Enge split-pole magnetic spectrograph using the technique of accelerator mass spectrometry. An overall sensitivity of ${10}^{\ensuremath{-}10}$ was achieved which proves accelerator mass spectroscopy to be a powerful tool for radioisotope detection also in a region of rather heavy ion masses. A detailed description of the subtleties of accelerator mass spectroscopy when applied to measure absolute radioisotope concentrations in this heavy mass region is presented.RADIOACTIVITY Measured half-life of $^{44}\mathrm{Ti}$ via accelerator mass spectroscopy.