The Doppler-shift-attenuation method was used to deduce lifetime information for electromagnetic transitions in ${\mathrm{B}}^{10}$, ${\mathrm{B}}^{11}$, ${\mathrm{B}}^{12}$, ${\mathrm{B}}^{13}$, ${\mathrm{C}}^{11}$, ${\mathrm{C}}^{14}$, ${\mathrm{N}}^{14}$, ${\mathrm{N}}^{15}$, ${\mathrm{N}}^{16}$, ${\mathrm{N}}^{17}$, ${\mathrm{O}}^{16}$, ${\mathrm{F}}^{18}$, ${\mathrm{Ne}}^{20}$, and ${\mathrm{Ne}}^{21}$. The combination of a Ge(Li) $\gamma$-ray detector and the use of lithium reactions permitted an accurate measurement of numerous lifetimes as well as the setting of improved limits for very fast lifetimes. In addition, a number of transition energies were measured with improved accuracy.

• Received 22 July 1968

DOI:https://doi.org/10.1103/PhysRev.179.1011