Half-life measurements on 29P and 33Cl

The half-life values for the β+ emitters 29P and 33Cl reported in the literature show a wide variation (4.6 ± 0.2 to 4.19 ± 0.02 s for 29P and 2.9 ± 0.1 to 2.51 ± 0.02 s for 33Cl). We have remeasured these activities via the Si(p,γ)P and S(p,γ)Cl reactions with protons from a 3 MV Van de Graaff. The decay positrons were detected in a solid-state detector telescope and the time distribution of the pulses was determined with a multiscaler controlled by a crystal clock. Data were analyzed by an iterative least-squares procedure and by the Fourier transform method. Values obtained were 4.15 ± 0.03 s for 29P and 2.47 ± 0.02 s for 33Cl.