Subjects: Physics >> Nuclear Physics submitted time 2024-02-05
Abstract: The feasibility of producing superheavy nuclei in proton evaporation channels was systematically studied within the dinuclear system (DNS) model. Due to the Z=114 proton-shell, one can synthesize Fl isotopes in proton evaporation channels. We only considered the case of evaporating one proton first and then n neutrons in this work, other cases were ignored due to the small cross-section. The production cross sections of unknown isotopes 290,291Fl in 38S+255Es reaction are the highest compared with 50Ti+243Np and 54Cr+239Pa reactions, and the maximum cross sections are 1.1 and 15.1 pb, respectively. 42S+254Es is a promising candidate to approach the island of stability as the radioactive beam facilities are upgraded in the future, and the production cross sections of 291−294Fl in that reaction are estimated to be 3.2, 6.0, 4.0, and 0.1 pb, respectively.
Subjects: Physics >> Nuclear Physics submitted time 2023-06-24
Abstract: The multinucleon transfer (MNT) reaction is one promising way to produce neutron-rich heavy nuclei and even super heavy nuclei and attracts more and more attentions theoretically and experimentally. A low energy nuclear structure spectrometer called LENSHIAF specific to the MNT reactions will be designed and constructed in the ongoing big project HIAF in China. In the LENSHIAF spectrometer, the most challenge part is how to collect and stop efficiently the high-energy MNT products into the gas cell. By using Monte-Carlo method, the geometry of the gas cell, the thickness of the titanium window/degrader, and the optimal gas pressure filled in the gas cell have been calculated and estimated. For neutron-rich nuclei around N=126 from 136Xe+198Pt reaction, with a titanium window/degrader with a thickness of 2.5–3.5 um, a cylindrical helium gas cell with a length of 0.6 m and a diameter of 1.2 m can satisfy the requirements to stop the target-like fragments. For heavier and super heavy nuclei from 238U+238U reaction, with a 5–8 um thick titanium window/degrader, the cylindrical gas cell has to be as big as a length of at least 1.6 m and a diameter of 1.6 m.
Subjects: Physics >> Nuclear Physics submitted time 2023-06-18 Cooperative journals: 《Nuclear Science and Techniques》
Abstract: The work is devoted to the implementation of the hydrodynamic laws to the head-on heavy ion collisions within the energy range 50–100 MeV/A. The hydrodynamic mechanisms of the bubble and ring structures formation are investigated. It is shown that there is a possible hydrodynamic explanation of the different structures being formed in the case of soft (K=200 MeV) and stiff (K=400 MeV) equations of state. Within the suggested approach the final geometry of the system is defined in the initial stage of the collision and is very dependent on the sound velocity in the nuclear matter. The obtained results are in a good correspondence with the Boltzmann-like transport theory calculations and the experimental data for the selected energy range.