Radioactive Decay ofSe83

An experimental investigation, using scintillation techniques, has been made of the gamma radiation emitted by the 69-second isomer of ${\mathrm{Se}}^{83}$. The ${\mathrm{Se}}^{83}$ was produced by irradiating selenium, enriched in the isotope ${\mathrm{Se}}^{82}$, in the reactor neutron flux. Gamma rays of energy 2.02±0.05 Mev, 1.01±0.02 Mev, 0.650±0.005 Mev, and 0.350±0.006 Mev were found, each with a (70±1)-second half-life. Of these, only the 0.350-Mev gamma ray was found in the 25-minute isomer. From these measurements, together with beta-gamma and gamma-gamma coincidence measurements and a rough beta-ray end-point determination, a decay scheme is proposed for the 69-second isomer of ${\mathrm{Se}}^{83}$.