The ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}(d, p){}_{}{}^{20}{}_{}{}^{}\mathrm{F}$ reaction has been used to study the mean lives, branching ratios, and excitation energies of several of the levels of ${}_{}{}^{20}{}_{}{}^{}\mathrm{F}$. The Doppler-shift attenuation method was used to obtain the following information concerning the mean lives of the low-lying levels in ${}_{}{}^{20}{}_{}{}^{}\mathrm{F}$: $\tau \left(0.66\mathrm{} \mathrm{MeV}\right)=(3.6\mathrm{}\pm 0.7)\times {10}^{-13\mathrm{}}$ sec, $\tau \left(0.82\mathrm{} \mathrm{MeV}\right)\ge 4.4\times {10}^{-12\mathrm{}}$ sec, $\tau \left(0.98\mathrm{} \mathrm{MeV}\right)=\left({{1.3}_{-0.4\mathrm{}}}^{+0.6\mathrm{}}\right)\times {10}^{-12\mathrm{}}$ sec, $\tau \left(1.06\mathrm{} \mathrm{MeV}\right)\le 9.2\times {10}^{-14\mathrm{}}$ sec, and $\tau \left(1.31\mathrm{} \mathrm{MeV}\right)=\left({{1.1}_{-0.3\mathrm{}}}^{+0.4\mathrm{}}\right)\times {10}^{-12\mathrm{}}$ sec. In addition, upper limits were found for levels at 2.04, 2.19, 2.96, 3.49, and 3.53 MeV. A previously unreported branching ratio of the 2.96-MeV level was found to be (2.96→ 0.0 MeV) 0.24±0.03, (2.96→0.66 MeV) 0.14±0.02, and (2.96→0.82 MeV) 0.62±0.06. A value of $3^{+}$ is suggested for the spin and parity of the 0.66-MeV level.

• Received 21 May 1969

DOI:https://doi.org/10.1103/PhysRev.186.1167