Half-life of Ti44

The half-life of Ti44 has been measured to be T12=54.2±2.1 yr, somewhat higher than previously published values of 46.4±1.7 and 48.2±0.9 yr. The present value was obtained from the specific activity and the radioisotope concentration of several TiO2 samples, each spiked with a Ti44 activity of about 1.2 μCi. The specific activity was measured via the 1157 keV γ line from the decay of the Sc44 daughter. Ti44/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 10-10 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 Ti44 via accelerator mass spectroscopy.