Dependence of heavy-ion fusion reaction on nuclear deformation and nuclear shell structure

• Published in: AIP Conference Proceedings Vol. 610; no. 1; pp. 604 - 607
• Main Authors: Ikezoe, H, Mitsuoka, S, Nishio, K, Satou, K, Nishinaka, I
• Format: Conference Proceeding Journal Article
• Language: English
• Published: United States 01.01.2002
• Subjects: BARIUM 134 TARGET; BARIUM 138 TARGET; COMPOUND NUCLEI; COULOMB FIELD; CROSS SECTIONS; DEFORMED NUCLEI; DISTANCE; EVAPORATION MODEL; GERMANIUM 76 REACTIONS; HEAVY ION FUSION REACTIONS; NEODYMIUM 150 TARGET; NICKEL 60 REACTIONS; NICKEL 64 REACTIONS; NUCLEAR DEFORMATION; NUCLEAR PHYSICS AND RADIATION PHYSICS; POTENTIAL ENERGY; SAMARIUM 154 TARGET; SELENIUM 82 REACTIONS; SHELL MODELS
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/1.1469999

The dependence of the fusion probability on the orientation of deformed nuclei was investigated for the Ni-(60, 64) + Sm-154 and Ge-76 + Nd-150 reactions. Evaporation residues were measured for these reaction systems in the vicinity of the Coulomb barrier, and the fusion probability was extracted as a function of bombarding energy. It was found that the fusion probability depends strongly on the orientation of the nuclear deformation. The fusion probability is considerably reduced when the projectiles collide at the tip of the deformed nuclei. On the other hand, when the projectiles collide at the side of the deformed nuclei, the fusion occurs without hindrance. This phenomenon is understood qualitatively by comparing the distance between the mass centers of two colliding nuclei at touching with the position of the saddle point of the compound nucleus. The dependence of the fusion probability on the nuclear shell structure was also investigated for the Se-82 + Ba-(134, 138) reactions, where the nucleus Ba-138 has a closed neutron shell of N = 82. The evaporation residue cross section for the Se-82 + Ba-134 reaction was about 100 times smaller than those for the Se-82 + Ba-138 reaction. (Author)