Nuclear shapes from alpha-gamma-ray angular correlations.

The angular distribution of alpha particles with respect to the spin direction of the residual nuclei is used to probe the shapes of the emitting systems. Two compound systems have been studied: $^{170}\mathrm{Yb}$ and $^{110}\mathrm{Sn}$. Deformed emission shapes are required in order to understand the alpha-gamma correlations in the $^{170}\mathrm{Yb}$ system, but not for the $^{110}\mathrm{Sn}$ compound system. These conclusions are identical to those reached by the study of giant resonances built on excited states for very similar systems.