${}_{}{}^{30}{}_{}{}^{}\mathrm{Al}$ was produced in the ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}({}_{}{}^{18}{}_{}{}^{}\mathrm{O},\alpha pn){}_{}{}^{30}{}_{}{}^{}\mathrm{Al}$ reaction by bombarding a ${\mathrm{Ta}}_2$ ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}_5^{}{}_{}{}^{}$ target with 42-MeV ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ ions. Following transfer of the target in a shuttle system the $\gamma$-ray spectrum was measured in a Ge(Li) detector. Nine $\gamma$-ray transitions were observed in ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}$ and have been fitted to an ${}_{}{}^{30}{}_{}{}^{}\mathrm{Al}$ decay scheme that includes five $\beta$-ray branches to excited states of ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}$. The half-life of ${}_{}{}^{30}{}_{}{}^{}\mathrm{Al}$ is 3.685±0.032 sec. ${}_{}{}^{30}{}_{}{}^{}\mathrm{P}$ was formed in the ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}\mathrm{}(p,n)\mathrm{}{}_{}{}^{30}{}_{}{}^{}\mathrm{P}$ reaction and a value of 2.499±0.008 min was obtained for its half-life. The ${\beta }^{+}$ branching of ${}_{}{}^{30}{}_{}{}^{}\mathrm{P}$ to the 2235-keV first excited state of ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}$ was found to be (0.061±0.006)%, differing from previous results. ${}_{}{}^{20}{}_{}{}^{}\mathrm{O}$, formed in the ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$)${}_{}{}^{20}{}_{}{}^{}\mathrm{O}$ reaction, was also studied and upper limits were placed on various $\beta$-decay branches. The half-life of ${}_{}{}^{20}{}_{}{}^{}\mathrm{O}$ was measured as 13.49±0.05 sec. $\mathrm{ft}$ values for the $\beta$ decay of ${}_{}{}^{30}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{30}{}_{}{}^{}\mathrm{P}$, and ${}_{}{}^{20}{}_{}{}^{}\mathrm{O}$ are compared with recent theoretical calculations.

[RADIOACTIVITY ${}_{}{}^{30}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{30}{}_{}{}^{}\mathrm{P}$, ${}_{}{}^{20}{}_{}{}^{}\mathrm{O}$: measured $T_{\frac{1}{2}}$, $I_{\gamma }$; deduced decay schemes, $log\mathrm{ft}$; compared with theory.]

• Received 6 March 1974

DOI:https://doi.org/10.1103/PhysRevC.9.2236