Decay ofNb92

Abstract

The decay scheme of ${\mathrm{Nb}}^{92}$ has been reexamined. Levels at 0.934 Mev (97.4% per disintegration) and 1.82 Mev (2.6%) were found. The 1.82-Mev state decays by 32% to the ground state and 68% to the 0.934-Mev state. This is in agreement with the work of Hayward, Hoppes, and Ernst. In addition a weak positron branch of (5.6\ifmmode\pm\else\textpm\fi{}0.6)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}2}$% per disintegration was found going to the 0.934-Mev level. Also, the angular correlation of the gamma-ray cascade was measured and found to be uniquely consistent with a level assignment of ${2}^{+}$, ${2}^{+}$, ${0}^{+}$, with essentially pure $M1$ radiation ($E2$ admixture 0.2%) for the ${2}^{+}$, ${2}^{+}$ transition. The large amount of $M1$ radiation in this type of transition is quite exceptional. Simple theoretical considerations indicate the gamma-ray transitions to be of the single-particle type.