Fast-Neutron Bombardment of Ni 64 and the Decay of Fe 61

A 6.15\ifmmode\pm\else\textpm\fi{}0.06-min activity, which has been assigned to the decay of ${\mathrm{Fe}}^{61}$, has been produced as the result of bombardment of nickel enriched in ${\mathrm{Ni}}^{64}$ with 15-19-MeV neutrons. The decay scheme has been studied by $\ensuremath{\beta}$, $\ensuremath{\gamma}$, $\ensuremath{\beta}\ensuremath{-}\ensuremath{\gamma}$, and $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ counting techniques using plastic scintillators, NaI(Tl) crystals, and a Ge(Li) detector. Evidence was found for levels in ${\mathrm{Co}}^{61}$ at 1.028\ifmmode\pm\else\textpm\fi{}0.005, 1.206\ifmmode\pm\else\textpm\fi{}0.005, 1.327\ifmmode\pm\else\textpm\fi{}0.005, 1.650\ifmmode\pm\else\textpm\fi{}0.015, and 1.995\ifmmode\pm\else\textpm\fi{}0.020 MeV.