Half-Lives of Some Nuclear States in the Millimicrosecond Region

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±0.04)×${10}^{-10\mathrm{}}$ sec; the 555-kev level in ${\mathrm{Mn}}^{52}$, (1.85±0.07)×${10}^{-9\mathrm{}}$ sec; the 1490-kev level in ${\mathrm{Co}}^{57}$, (1.00±0.05)×${10}^{-9\mathrm{}}$ sec; the 245-kev level in ${\mathrm{Se}}^{77}$, (1.30±0.08)×${10}^{-9\mathrm{}}$ sec; the 155-kev level in ${\mathrm{Sb}}^{119}$, (0.83±0.2)×${10}^{-9\mathrm{}}$ sec; the 123-kev level in ${\mathrm{Cs}}^{131}$, (4.15±0.08)×${10}^{-9\mathrm{}}$ sec; and the 103-kev level in ${\mathrm{Eu}}^{153}$, (3.8±0.02)×${10}^{-9\mathrm{}}$ sec. The well-known level of ${\mathrm{Ta}}^{181}$ at 48 kev gives (1.10±0.02)×${10}^{-8\mathrm{}}$ sec and that of ${\mathrm{Gd}}^{154}$ at 122 kev, 1.15×${10}^{-9\mathrm{}}$ sec. A comparison with the results given by theory is made.