The lifetimes of a number of rotational nuclear levels have been measured in a pulsed-beam experiment. Gamma rays were counted and timed in a cooled unactivated NaI crystal. The excited states investigated were the first-excited levels in ${\mathrm{Gd}}^{158}$, ${\mathrm{Yb}}^{172,174,176}$, ${\mathrm{Hf}}^{177}$, and ${\mathrm{W}}^{182,184,186}$.

• Received 6 December 1961

DOI:https://doi.org/10.1103/PhysRev.126.726