Half-Lives of Some Nuclear States in the Millimicrosecond Region

Abstract

A time-to-pulse height converter, fast coincidence arrangement, and multichannel analyzer were used to measure half-lives of some nuclear states in the millimicrosecond range. The half-lives of the following nuclear states were measured: the 325-kev level in ${\mathrm{V}}^{51}$, (2.80\ifmmode\pm\else\textpm\fi{}0.04)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ sec; the 555-kev level in ${\mathrm{Mn}}^{52}$, (1.85\ifmmode\pm\else\textpm\fi{}0.07)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec; the 1490-kev level in ${\mathrm{Co}}^{57}$, (1.00\ifmmode\pm\else\textpm\fi{}0.05)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec; the 245-kev level in ${\mathrm{Se}}^{77}$, (1.30\ifmmode\pm\else\textpm\fi{}0.08)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec; the 155-kev level in ${\mathrm{Sb}}^{119}$, (0.83\ifmmode\pm\else\textpm\fi{}0.2)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec; the 123-kev level in ${\mathrm{Cs}}^{131}$, (4.15\ifmmode\pm\else\textpm\fi{}0.08)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec; and the 103-kev level in ${\mathrm{Eu}}^{153}$, (3.8\ifmmode\pm\else\textpm\fi{}0.02)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec. The well-known level of ${\mathrm{Ta}}^{181}$ at 48 kev gives (1.10\ifmmode\pm\else\textpm\fi{}0.02)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}8}$ sec and that of ${\mathrm{Gd}}^{154}$ at 122 kev, 1.15\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}9}$ sec. A comparison with the results given by theory is made.