No abstract

The ground state half-lives of 69 Ge, 73 Se, 83 Sr, 63 Zn, and the half-life of the 1/2isomer in 85 Sr have been measured with high precision using the photoactivation technique at an unconventional bremsstrahlung facility that features a repurposed medical electron linear accelerator. The -ray activity was counted over about 6 half-lives with a high-purity Germanium detector, enclosed into an ultra low-background lead shield. The measured half-lives are: T1/2( 69 Ge) = 38.82  0.07 (stat)  0.06 (sys) h; T1/2( 73 Se) = 7.18  0.02 (stat)  0.004 (sys) h; T1/2( 83 Sr) = 31.87  1.16 (stat)  0.42 (sys) h; T1/2( 85m Sr) = 68.24  0.84 (stat)  0.11 (sys) min; T1/2( 63 Zn) = 38.71  0.25 (stat)  0.10 (sys) min. These high-precision half-life measurements will contribute to a more accurate determination of corresponding ground-state photoneutron reaction rates, which are part of a broader effort of constraining statistical nuclear models needed to calculate stellar nuclear reaction rates relevant for the astrophysical p-process nucleosynthesis.