The alpha-decay branching ratio for the lowest isobaric analog state in ${}_{}{}^{69}{}_{}{}^{}\mathrm{Ge}$ has been measured to be less than 1.0×${10}^{\mathrm{-}2}$. Transitions to this level contribute significantly to the cross section for the capture of high-energy neutrinos by ${}_{}{}^{69}{}_{}{}^{}\mathrm{Ga}$. Since the analog state decays almost exclusively by gamma-ray emission, induced ${}_{}{}^{69}{}_{}{}^{}\mathrm{Ge}$ radioactivity may be used for the detection of high-energy neutrinos in large-scale gallium neutrino detectors.

• Received 29 July 1988

DOI:https://doi.org/10.1103/PhysRevC.38.2430