Suppression of Neutron Emission in Heavy Ion Induced Fusion Reactions: Entrance Channel Effect and/or Superdeformed Shapes

摘要

In the 233-MeV sup 64 Ni + sup 92 Zr reaction the emission of two neutrons constitutes the strongest decay channel, in contrast to statistical model calculations which predict the emission of three neutrons to be the strongest by more than one order of magnitude. Possible explanations for the apparent neutron suppression in terms of unusually large gamma-decay width, anomalously energetic neutrons or an unknown yrast line have been ruled out. Here we report on a series of experiments aimed at a better understanding of this suppression. The neutron multiplicity M/sub n/ has been obtained for the 55 to 75 MeV sup 12 C + sup 144 Sm and the 225 to 290 MeV sup 64 Ni + sup 92 Zr reactions leading to the same compound nucleus sup 156 Er. (ERA citation 10:035384)