One-neutron transfer, complete fusion, and incomplete fusion from the ${}^9\mathrm{Be}$ $+$ ${}^{197}\mathrm{Au}$ reaction

In this work, one-neutron transfer (pickup and stripping), complete and incomplete fusion cross sections for the ${}^9\mathrm{Be}+{}^{197}\mathrm{Au}$ system were measured over a wide range of energies around the Coulomb barrier by the offline $\gamma$-ray detection method. Coupled-channel calculations were used to determine the elastic, inelastic, and transfer cross sections. Coupled reaction channel calculations were performed to derive the one-neutron stripping and pickup cross sections. Three-body continuum discretized coupled-channel calculations were used to determine the effect of the breakup channel on the other reaction mechanisms. The reduced complete and total fusion were found to be hindered above and enhanced below the Coulomb barrier compared with the universal fusion function due to the breakup plus transfer effects.

Figure 1

Decay scheme of the CF and ICF compound nuclei and transfer products identified in the $\gamma$ spectrum. Stable nuclides are depicted in black. Red colored nuclides decay via ${\beta }^{+}$ and/or electron capture, whereas the blue colored nuclei decay via ${\beta }^{-}$. ${}^{202}\mathrm{Pb}$, with a half-life too long to be detected (53 ky), is depicted in light red. ($\alpha$, $x$) stands for the ICF following the ${}^9\mathrm{Be}$ prompt breakup.

Figure 2

Offline $\gamma$-ray spectrum measured from an activated set of target plus catcher at an incident energy of 48 MeV.

Figure 3

Activity of the main produced nuclei as a function of time. An exponential decay fit was performed to extract half-life values for each reaction channel. All resulting values are in agreement with those in Table 1.

Figure 4

Experimental cross sections (full symbols) for the CF, ICF, and $n$-transfer channels measured for the ${}^9\mathrm{Be}+{}^{197}\mathrm{Au}$ system. In solid lines, pace2 calculations are included for the CF neutron evaporation channels. Cross sections obtained by Li et al. [42] and Kaushik et al. [43] are also included (open symbols). Finally, in bottom right panel, CF and TF (CF $+$ ICF) cross section are presented. ${\sigma }_{CF}$ were corrected based on pace2 calculations of the ratio ${\sigma }_{3n+4n+5n}/{\sigma }_{\text{fus}}$.

Figure 5

Comparison between the experimental data and the theoretical CC calculations for the elastic scattering.

Figure 6

Comparison between the experimental data with the theoretical inelastic calculations. The dashed lines represent the cross section of 279.0 keV (5/$2^{+}$) and the dash-dotted line represents the 270.0 kev (3/$2^{+}$) states of ${}^{197}\mathrm{Au}$.

Figure 7

Coupling scheme of the projectile and target overlaps used in the one-neutron stripping transfer reaction calculations.

Figure 8

Comparison between the experimental data with the theoretical one-neutron transfer and elastic breakup cross section.

Figure 9

Comparison between all the waves considered in the CDCC calculations. The inset shows the polarization potential close to the barrier radius, both for 40 MeV.

Figure 10

Coupling scheme of the projectile and target overlaps used in the one-neutron pickup reaction calculations.

Figure 11

Comparison between the experimental data with the theoretical one-neutron pickup calculations.

Figure 12

Comparison between the UFF and renormalized fusion function for total fusion (CF). The systems are composed by the ${}^9\mathrm{Be}$ projectile on different targets: ${}^{186}\mathrm{W}$ [88], ${}^{144}\mathrm{Sm}$ [89], ${}^{208}\mathrm{Pb}$ [13], ${}^{197}\mathrm{Au}$ from Refs. [42, 43] and this work.

Figure 13

Comparison between the UFF and renormalized fusion function for total fusion (TF). The systems are composed by the ${}^9\mathrm{Be}$ projectile on different targets: ${}^{186}\mathrm{W}$ [88], ${}^{144}\mathrm{Sm}$ [89], ${}^{208}\mathrm{Pb}$ [13], ${}^{197}\mathrm{Au}$ from Ref. [42] and this work.