Population of superdeformed bands at extreme angular momenta

A study of superdeformed band population at very high angular momenta was undertaken with the reactions 76Ge+76Ge and 28Si+124Sn. Both reactions formed the compound nucleus 152Gd at an excitation energy of 87 MeV. Relative to normally deformed states, the yrast superdeformed band in the residual nucleus 147Gd was found to be populated 4.6±0.2 times more strongly for the mass-symmetric reaction compared to the mass-asymmetric reaction. Such a large difference in the population was not expected. Also, the superdeformed continuum feeding the yrast superdeformed states in 147Gd was found to be at least 12 times stronger for the mass-symmetric reaction.