Lifetime of theF210.28-MeV Level

The mean lifetime of the first excited state of ${\mathrm{F}}^{21}$ at 0.28 MeV has been measured to be (8.31±0.36)×${10}^{-9\mathrm{}}$ sec, consistent with a transition multipolarity $E2\mathrm{}$. Also, the angular distribution of the gamma radiation following the decay of this level (employing the geometry of Litherland and Ferguson) was found to be isotropic. The ${\mathrm{F}}^{19}(t, p){\mathrm{F}}^{21}$ reaction was used to populate the 0.28-MeV level of ${\mathrm{F}}^{21}$.