High precision measurements of half-lives for 69Ge, 73Se, 83Sr, 85mSr, and 63Zn radionuclides relevant to the astrophysical p-process via photoactivation at the Madison Accelerator Laboratory

TL;DR

This study precisely measured the half-lives of five radionuclides relevant to the astrophysical p-process using photoactivation, providing data to improve nuclear reaction models for stellar nucleosynthesis.

Contribution

The paper presents high-precision half-life measurements of five radionuclides using a novel photoactivation method at a medical linear accelerator.

Findings

Half-lives of five radionuclides were measured with high precision.

Results will improve nuclear reaction rate calculations for astrophysical models.

Data supports better constraints on statistical nuclear models.

Abstract

The ground state half-lives of 69Ge, 73Se, 83Sr, 63Zn, and the half-life of the 1/2- isomer in 85Sr have been measured with high precision using the photoactivation technique at an unconventional bremsstrahlung facility that features a repurposed medical electron linear accelerator. The g-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(69Ge) = 38.82 +/- 0.07 (stat) +/- 0.06 (sys) h; T1/2(73Se) = 7.18 +/- 0.02 (stat) +/- 0.004 (sys) h; T1/2(83Sr) = 31.87 +/- 1.16 (stat) +/- 0.42 (sys) h; T1/2(85mSr) = 68.24 +/- 0.84 (stat) +/- 0.11 (sys) min; T1/2(63Zn) = 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.