Bimodal fission of Hs*

International Symposium on Entrance Channel Effect on the Reaction Mechanism in Heavy Ion Collisions

Itkis, I.M.^1 ; Itkis, M.G.^1 ; Knyazheva, G.N.^1 ; Kozulin, E.M.^1 ; Loktev, T.A.^1 ; Novikov, K.V.^1 ; Hanappe, F.^2 ; Vardaci, E.^3

FLNR, Joint Institute for Nuclear Research, 141980 Dubna, Russia^1

Université Libre de Bruxelles, CP229, B-1050, Belgium^2

Istituto Nazionale di Fisica Nucleare, Dipartimento di Scienze Fisiche dell'Università di Napoli, Napoli, Italy^3

关键词: Energy distributions;    Energy shells;    Fission fragment;    Gaussian shape;    High-energy components;    Initial excitation;    Low-energy components;    Neutron shells;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/515/1/012008/pdf
DOI  :  10.1088/1742-6596/515/1/012008

来源: IOP

【 摘 要 】

Mass and energy distributions of fission fragments obtained in the reactions22Ne +249Cf,26Mg +248Cm, and22Ne +238U have been measured. A special attention will be paid on the properties of mass-energy distribution of fission fragments obtained in the reaction26Mg +248Cm at an excitation energy of 35 MeV. At this energy shell effects should become more effective in fission, the TKE distribution of symmetric fragments obtained in the reaction26Mg +248Cm differs strongly from a Gaussian shape. Besides a low-energy component, a high-energy component, not foreseen in the LDM, arises. This is attributed to the fact that both fission fragments are close to the spherical neutron shell N 82. It means that for the compound nucleus274Hs*, formed in the reaction26Mg +248Cm, the phenomenon of bimodal fission was observed for the first time. For the compound nucleus260No* formed in the reaction22Ne +238U at the initial excitation energy of 41 MeV the bimodal fission as well as superasymmetric fission were observed.