Decay ofMg27

The gamma rays accompanying the decay of 9.45-min ${\mathrm{Mg}}^{27}$ have been studied by use of a NaI scintillation spectrometer and beta-gamma coincidence counting. Three gamma rays of energies 0.834, 1.015, and 0.175 Mev were found with relative intensities of 1.00, 0.43, and 0.009. The isotopic thermal-neutron activation cross section for production of ${\mathrm{Mg}}^{27}$ is found to be 25±2 millibarns.