β+–electron-capture decay ofSe69

The ${\beta }^{+}$–electron-capture decay of ${}_{}{}^{69}{}_{}{}^{}\mathrm{Se}$, produced via the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ ${(}^{32}$S, 2pn${)}^{69}$Se reaction, has been studied by β-delayed proton and γ-ray emissions using the recoil transport helium jet technique. The established decay scheme for ${}_{}{}^{69}{}_{}{}^{}\mathrm{Se}$ involves 13 up to now unreported γ emitting levels in ${}_{}{}^{69}{}_{}{}^{}\mathrm{As}$. The total proton branching ratio has been measured to be (4.5±1.0)×${10}^{\mathrm{-}4}$. The autocorrelation analysis of the delayed proton spectra indicates a level spacing in agreement with the back shifted Fermi gas model estimates. The Gamow-Teller beta strength distribution has been measured in 95% of the $Q_{\beta }$ window, up to 6.5 MeV excitation energy in ${}_{}{}^{69}{}_{}{}^{}\mathrm{As}$.