The nuclide ${}_{}{}^{259}{}_{}{}^{}104$ has been produced in the ${}_{}{}^{249}{}_{}{}^{}\mathrm{Cf}({}_{}{}^{13}{}_{}{}^{}\mathrm{C},3n)$ reaction. Alpha particle groups of 8.77±0.01 MeV and 8.87±0.01 MeV were attributed to the decay of ${}_{}{}^{159}{}_{}{}^{}104$, and the measured half-life was found to be 3.0±1.3 s. The branching ratio for spontaneous fission decay was determined to be 0.063±0.037.

RADIOACTIVITY, FISSION ${}_{}{}^{259}{}_{}{}^{}104\left(\mathrm{sf} \mathrm{and} \alpha \right)$, measured $T_{\frac{1}{2}}$, $E_{\alpha }$, $I_{\alpha }$, $I_{\mathrm{sf}}$, $\sigma$ for ${}_{}{}^{249}{}_{}{}^{}\mathrm{Cf}({}_{}{}^{13}{}_{}{}^{}\mathrm{C},3n)$ and ${}_{}{}^{249}{}_{}{}^{}\mathrm{Cf}({}_{}{}^{13}{}_{}{}^{}\mathrm{C},\sigma 2n)$ reactions; deduced $\frac{\mathrm{sf}}{\alpha }$ for ${}_{}{}^{259}{}_{}{}^{}104$; enriched target.

• Received 19 February 1980

DOI:https://doi.org/10.1103/PhysRevC.23.555