Influence of entrance channel on production cross sections of superheavy nuclei

The dependence of the evaporation residue cross section (ERCS) to produce superheavy nuclei (SHN) on the entrance channel of colliding nuclei is analyzed within the dinuclear system concept. The ERCS for the hot fusion reactions are investigated systematically and compared with existing experimental data. The capture cross section depends sensitively on the reaction $Q$ value. The fusion probabilities and surviving probabilities depend sensitively on the neutron numbers of the target and projectile nuclei. In most cases more neutron excess in the system can increase the producing cross section of SHN.

Figure 1

The calculated ERCSs compared with the available experimental data for the reactions (a)${}^{18}\mathrm{O}+{}^{248}\mathrm{Cm}$, (b)${}^{22}\mathrm{Ne}+{}^{244}\mathrm{Pu}$, (c)${}^{22}\mathrm{Ne}+{}^{242}\mathrm{Pu}$, (d)${}^{26}\mathrm{Mg}+{}^{238}\mathrm{U}$, (e)${}^{15}\mathrm{N}+{}^{249}\mathrm{Cf}$, (f)${}^{16}\mathrm{O}+{}^{249}\mathrm{Bk}$, (g)${}^{18}\mathrm{O}+{}^{249}\mathrm{Bk}$, and (h)${}^{19}\mathrm{F}+{}^{248}\mathrm{Cm}$. The measured ERCSs of the $3n,4n$, and $5n$ channels are denoted by red solid squares, blue open cycles, and green open squares, respectively. The calculated results of the $3n,4n$, and $5n$ channels are denoted by red solid lines, blue solid lines, and green solid lines, respectively.

Figure 2

The calculated ERCSs compared with the available experimental data for the reactions (a)${}^{22}\mathrm{Ne}+{}^{241}\mathrm{Am}$, (b)${}^{30}\mathrm{Si}+{}^{238}\mathrm{U}$, (c)${}^{18}\mathrm{O}+{}^{249}\mathrm{Cf}$, (d)${}^{22}\mathrm{Ne}+{}^{248}\mathrm{Cm}$, (e)${}^{22}\mathrm{Ne}+{}^{249}\mathrm{Bk}$, (f)${}^{26}\mathrm{Mg}+{}^{248}\mathrm{Cm}$, (g)${}^{36}\mathrm{S}+{}^{238}\mathrm{U}$, and (h)${}^{34}\mathrm{S}+{}^{238}\mathrm{U}$. The measured ERCSs of the $3n,4n$, and $5n$ channels are denoted by red solid squares, blue open cycles, and green open squares, respectively. The calculated results of the $3n,4n$, and $5n$ channels are denoted by red solid lines, blue solid lines, and green solid lines, respectively.

Figure 3

The calculated ERCSs compared with the available experimental data for the reactions (a)${}^{48}\mathrm{Ca}+{}^{226}\mathrm{Ra}$, (b)${}^{48}\mathrm{Ca}+{}^{232}\mathrm{Th}$, (c)${}^{48}\mathrm{Ca}+{}^{238}\mathrm{U}$, (d)${}^{48}\mathrm{Ca}+{}^{237}\mathrm{Np}$, (e)${}^{48}\mathrm{Ca}+{}^{239}\mathrm{Pu}$, (f)${}^{48}\mathrm{Ca}+{}^{240}\mathrm{Pu}$, (g)${}^{48}\mathrm{Ca}+{}^{242}\mathrm{Pu}$, and (h)${}^{48}\mathrm{Ca}+{}^{244}\mathrm{Pu}$. The measured ERCSs of the $3n,4n$, and $5n$ channels are denoted by red solid squares, blue open cycles, and green open squares, respectively. The calculated results of the $3n,4n$, and $5n$ channels are denoted by red solid lines, blue solid lines, and green solid lines, respectively.

Figure 4

The calculated ERCSs compared with the available experimental data for the reactions (a)${}^{48}\mathrm{Ca}+{}^{243}\mathrm{Am}$, (b)${}^{48}\mathrm{Ca}+{}^{245}\mathrm{Cm}$, (c)${}^{48}\mathrm{Ca}+{}^{248}\mathrm{Cm}$, (d)${}^{48}\mathrm{Ca}+{}^{249}\mathrm{Bk}$, and (e)${}^{48}\mathrm{Ca}+{}^{249}\mathrm{Cf}$. The measured ERCSs of the $3n,4n$, and $5n$ channels are denoted by red solid squares, blue open cycles, and green open squares, respectively. The calculated results of the $3n,4n$, and $5n$ channels are denoted by red solid lines, blue solid lines, and green solid lines, respectively.

Figure 5

(a) The parameter $a$ represents the surface diffuseness of the nuclear density distribution. Comparison of the calculated capture cross sections based on different surface diffuseness $a=0.54\mathrm{fm}$ (black line) and $a=0.50\mathrm{fm}$ (red line) with the experimental data for the ${}^{26}\mathrm{Mg}+{}^{248}\mathrm{Cm}$ reaction. The black arrow shows the corresponding positions of the Bass barrier [59]. (b) Comparison of the capture cross sections calculated in the present work for the ${}^{26}\mathrm{Mg}+{}^{248}\mathrm{Cm}$ (black line), ${}^{30}\mathrm{Si}+{}^{244}\mathrm{Pu}$ (red line), ${}^{36}\mathrm{S}+{}^{238}\mathrm{U}$ (blue line), and ${}^{48}\mathrm{Ca}+{}^{226}\mathrm{Ra}$ (green line) reactions. The surface diffuseness $a=0.50\mathrm{fm}$ is adopted in the present systematic calculation.