The mean life of the first excited state of ${\mathrm{O}}^{17}$ at 871 keV has been measured by a pulsed Van de Graaff beam technique. A value of ${\tau }_m=(0.263\mathrm{}\pm 0.008)$ nsec was found. Similar measurements on the first excited state of ${\mathrm{F}}^{18}$ at 940 keV established an upper limit to the mean life: ${\tau }_m<0.2\mathrm{}$ nsec.

• Received 8 May 1963

DOI:https://doi.org/10.1103/PhysRev.132.367