The synthesis of superheavy nuclei (SHN) is a leading research frontier in nuclear physics today. In experiments on synthesizing SHN through fusion-evaporation reactions, selecting an appropriate projectile-target combination and determining the optimal incident energy are crucial. The number of SHN that can be synthesized with stable projectiles is very small. The fusion-evaporation reaction with a radioactive projectile is one of the promising ways for SHN synthesis, and it is of great significance to conduct in-depth research on this kind of reaction. In this work, a systematic study is carried out on the fusion-evaporation reactions with radioactive projectiles. The capture cross section is calculated with the empirical coupled channel model, the fusion probability is computed by the dinuclear system model with a dynamical potential energy surface (DNS-DyPES model) and the survival probability is determined through the statistical model.
In the systematic study, 11 actinide isotopes with Z=90–100 are used as targets which are ^232\rmTh, ^231\rmPa, ^238\rmU, ^237\rmNp, ^244\rmPu, ^243\rmAm, ^248\rmCm, ^249\rmBk, ^251\rmCf, ^254\rmEs and ^257\rmFm. Projectiles are isotopes between proton and neutron drip lines for elements Z=4–32 and most of these projectiles are radioactive. By combining these projectiles and targets, 4969 reaction systems are proposed for synthesizing the isotopes of superheavy elements Z=104–122. Through large-scale calculations, the excitation functions for 2n–5n evaporation channels of each reaction system are obtained. Using the results of these reaction systems, we establish a synthesis cross section dataset for superheavy nuclei. For each reaction system, the dataset includes the identities of the synthesized SHN, the optimal incident energies, and the maximal evaporation residue cross sections in 2n–5n evaporation channels. This dataset may serve as a theoretical support for synthesizing new superheavy nuclides and elements.
Additionally, taking the reactions with ^232\rmTh target as examples, we discuss systematic trends in the results and explore the underlying SHN synthesis mechanism. The synthesis cross sections of these reactions are significantly different. We find that the inner fusion barrier of the compound system forms after the projectile has touched the target and the fission barrier of the compound nucleus are key factors that influence the synthesis cross section. Qualitatively, the projectile-target combinations with relatively large synthesis cross sections possess a lower inner fusion barrier in the compound system forms upon contact, which is favorable for fusion, and a higher fission barrier in the compound nucleus, thereby enhancing the survival probability. These conclusions may provide valuable references for advancing theoretical research related to the synthesis of superheavy nuclei. The dataset presented in this paper are available at
http://www.doi.org/10.57760/sciencedb.27854.