Energy-Dependent Multiplicities of ContinuumγRays

Multiplicities as a function of $\gamma$-ray energy have been measured for continuum $\gamma$ray spectra produced in argon reactions at several bombarding energies on various targets. With the heavier systems there exist regions in the spectra that have particularly high multiplicites which can be associated with the yrast (collective) cascade. The results suggest that the angular momentum in the $\gamma$-ray cascade is limited by $\alpha$ emission for $Z\lesssim 60$ and by fission for $Z\gtrsim 60$.