Production of ${}^{61}\mathrm{Ca}, {}^{63}\mathrm{Sc}, {}^{65}\mathrm{Ti}, {}^{68,69}\mathrm{V}, {}^{71}\mathrm{Cr}, {}^{77}\mathrm{Fe}$, and ${}^{79}\mathrm{Co}$ in projectile fragmentation with radioactive ion beams at $1A$ GeV

Projectile fragmentation provides an method to produce the unknown neutron-rich isotopes. In this work, the isospin-dependent Boltzmann-Langevin equation is employed to investigate the influence of projectiles on the fragments production. The cross sections of fragments with proton number $Z=20$–27 are calculated under the reaction systems ${}^{81,84,86}\mathrm{Ga}+{}^9\mathrm{Be}$. The obtained results suggest that the radioactive projectile ${}^{86}\mathrm{Ga}$ is favorable to the yields of neutron-rich nuclei. The newly produced isotopes ${}^{61}\mathrm{Ca}, {}^{63}\mathrm{Sc}, {}^{65}\mathrm{Ti}, {}^{68,69}\mathrm{V}, {}^{71}\mathrm{Cr}, {}^{77}\mathrm{Fe}$, and ${}^{79}\mathrm{Co}$, whose cross sections are characterized by the order of 1 to 100 $\mu \mathrm{b}$, can be observed in the reaction ${}^{86}\mathrm{Ga}+{}^9\mathrm{Be}$ at $1A$ GeV. This means the production cross sections of neutron-rich nuclei are very highly sensitive to the neutron-proton excess of projectile.

Figure 1

Fragment cross sections plotted as a function of neutron excess in the reaction ${}^{69}\mathrm{Cu}+{}^9\mathrm{Be}$ at $98.1A\text{MeV}$. The solid lines denote the calculated results obtained by the IBLE model, while the solid circle represents the experiment data coming from Ref. [46].

Figure 2

The isotopic cross sections in the reactions ${}^{81,84,86}\mathrm{Ga}+{}^9\mathrm{Be}$ at $1A$ GeV. The solid, dashed, and dash-dotted lines represent the result of these three reactions, respectively. Unknown nuclei are denoted by the open symbols.

Figure 3

(a) Mean $\langle N\rangle /Z$ ratio for reactions ${}^{81,84,86}\mathrm{Ga}+{}^9\mathrm{Be}$. (b) The results for $Z=20$ (solid line) and $Z=27$ (dash-dotted line) as a function of the $N/Z$ value of the projectile.

Figure 4

Fragments produced in the $1A$ GeV ${}^{86}\mathrm{Ga}+{}^9\mathrm{Be}$ reaction within different impact parameters b. The solid, dashed, and dash-dotted lines represent the result of the central, semiperipheral and peripheral collisions, respectively.

Figure 5

The nuclei region from $Z=20$ to $Z=27$ on the nuclear map. The filled and open squares denote the known and unknown nuclei, respectively.

Figure 6

Values of the factor $\kappa (=\sigma \varphi )$ for the predicted Ca, Sc, Ti, V, Cr, Fe, and Co isotopes in the reaction ${}^{86}\mathrm{Ga}+{}^9\mathrm{Be}$. $\sigma$ is the production cross section, $\varphi$ is the beam intensity. The blank symbols denote the predicted unknown nuclei.