Heavy-ion reaction and fission studies at the JAEA tandem accelerator facility

Nishio, Katsuhisa   

This talk will discuss the heavy-ion reaction and fission studies at the JAEA tandem accelerator facility. Heavy-ion fusion reactions have been studied to understand the mechanism for the synthesis of super-heavy elements, where effects of static deformation of the target nucleus U were investigated in the reactions using various projectile nuclei. Recently, we are promoting a program of fission/reaction studies in multi-nucleon transfer reactions. This approach allows us to investigate fission of neutron-rich nuclei, which cannot be populated by particle capture reactions. From the measurement of fission fragment mass distributions (FFMDs) for various nuclides and their evolution with initial excitation energy, role of multi-chance fission on FFMD was investigated. The obtained data set was used to improve the Langevin model to describe low-energy fission, which derives a clear explanation of the transition from the mass-asymmetric fission to the sharp symmetric fission observed in fermium isotopes. In addition to FFMDs, prompt neutrons have been measured in correlation with fission fragments for the fission and reaction studies.