Study of the Level Structure ofTi50andTi51Using theTi49(n,γ)andTi50(n,γ)Reactions

The capture $\gamma$-ray spectrum resulting from thermal-neutron capture in ${}_{}{}^{49}{}_{}{}^{}\mathrm{Ti}$ and ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$ has been measured using a 30- and a 10-${\mathrm{cm}}^3$ Ge(Li) detector, and angular-correlation measurements were carried out using NaI(Tl) detectors. Some 16 $\gamma$ lines corresponding to transitions between levels of ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$, and 9 $\gamma$ lines corresponding to transitions between levels of ${}_{}{}^{51}{}_{}{}^{}\mathrm{Ti}$ were observed. The neutron separation energies of ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$ and ${}_{}{}^{51}{}_{}{}^{}\mathrm{Ti}$ were determined to be 10.938 ± 0.008 and 6.377 ± 0.007 MeV, respectively. The following assignments of spins for some levels (in MeV) of ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$ and the first excited level of ${}_{}{}^{51}{}_{}{}^{}\mathrm{Ti}$ were made: 1.555 ($2^{+}$), 2.675 ($4^{+}$), 4.151 [$2^{+}$, $3^{+}$, $4^{+}$, ($5^{+}$)], 4.178 ($2^{+}$, $3^{+}$, $4^{+}$), 4.887 [$2^{+}$, $3^{+}$, $4^{+}$, ($5^{+}$)], 5.195 ($2^{+}$, $3^{+}$, $4^{+}$), 5.382 [$2^{+}$, $3^{+}$, $4^{+}$, ($5^{+}$)], 5.948 [$3^{+}$, $4^{+}$, ($5^{+}$)] for ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$ and 1.164 (${\mathrm{½}}^{-}$) for ${}_{}{}^{51}{}_{}{}^{}\mathrm{Ti}$. There are some indications that only the $3^{-}$ capture-state spin contributes to the population of the low-lying levels in ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$. The results of a comparison between the measured strengths of exciting the ${}_{}{}^{50}{}_{}{}^{}\mathrm{Ti}$ levels in the ($n,\gamma$) and ($d,p$) reactions are discussed.