2016/05/24 by Kai Zhao, Zhuxia Li, Yingxun Zhang +5 · 57 citations
Engineering · Physics and Astronomy · #Atomic physics #Isotope #Neutron #Nuclear Physics and Applications #Nuclear physics #Nuclear physics research studies #Nuclear reactor physics and engineering #Nucleon #Physics #Production (economics) #nucl-th
paper · pdf · doi:10.1103/physrevc.94.024601
published in Physical Review C 94(2) (American Institute of Physics)
arxiv created 2016/05/24 · openalex created_date 2016/06/24 · openalex publication_date 2016/08/01 · arxiv updated 2016/08/24 · openalex updated_date 2026/08/05
The production cross sections for primary and residual fragments with charge number from Z=70 to 120 produced in the collision of 238U+\phantom\rule0.16em0ex238U at 7.0 MeV/nucleon are calculated by the improved quantum molecular dynamics (ImQMD) model incorporated with the statistical evaporation model (hivap code). The calculation results predict that about 60 unknown neutron-rich isotopes from elements Ra (Z=88) to Db (Z=105) can be produced with the production cross sections above the lower bound of 10^\ensuremath-8 mb in this reaction. And almost all of the unknown neutron-rich isotopes are emitted at the laboratory angles \ensuremathθlab\ensuremath≤60^\ensuremath∘. Two cases, i.e., the production of the unknown uranium isotopes with A\ensuremath≥244 and that of rutherfordium with A\ensuremath≥269, are investigated to understand the production mechanism of unknown neutron-rich isotopes. It is found that for the former case the collision time between two uranium nuclei is shorter and the primary fragments producing the residues have smaller excitation energies of \ensuremath≤30 MeV and the outgoing angles of those residues cover a range of 30^\ensuremath∘--60^\ensuremath∘. For the latter case, a longer collision time is needed for a large number of nucleons being transferred and thus it results in higher excitation energies and smaller outgoing angles of primary fragments, and eventually results in a very small production cross section for the residues of Rf with A\ensuremath≥269 which have a small interval of outgoing angles of \ensuremathθlab=40^\ensuremath∘--50^\ensuremath∘.