Nucleon Transfer inB10(N14,N13)B11,B10(N14,C11)C13, andCa40(N14,N13)Ca41Reactions

Abstract

Thin targets of ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ were bombarded with ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ ions from the Oak Ridge tandem van de Graaff accelerator. Ranges, angular distributions $\frac{d\sigma \left(\theta \right)}{d\Omega }$, and total cross sections $\sigma \mathrm{}\left(E\right)\mathrm{}$ were obtained by measuring the activities of the positron emitters ${}_{}{}^{13}{}_{}{}^{}\mathrm{N}$ and ${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ formed in the neutron and proton transfer reactions. The ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$(${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$,${}_{}{}^{13}{}_{}{}^{}\mathrm{N}$)${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ reaction was shown to involve primarily ground states of ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ at an incident energy of 16.3 MeV. The angular-distribution data for this reaction were found, in their dependence on angle, to be consistent with tunneling-theory calculations. [Although cross-section calculations with the tunneling theory have been limited to the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$(${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$,${}_{}{}^{13}{}_{}{}^{}\mathrm{N}$)${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$ reaction, the angular dependence calculated for the differential cross section can be used for other reactions.] A reduced width for the transferred neutron could not be determined, however, because of the specialization of the calculations to the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$(${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$,${}_{}{}^{13}{}_{}{}^{}\mathrm{N}$)${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$ reaction. In the ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$(${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$,${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$)${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ reaction, the protons transfer to both the ground state and first excited state of ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, but no transfers involving the first excited state of ${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$ were observed. For the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$,${}_{}{}^{13}{}_{}{}^{}\mathrm{N}$)${}_{}{}^{41}{}_{}{}^{}\mathrm{Ca}$ experiments, reactions were found at the higher energies measured (>27.5 MeV) which led to excited states as well as to the ground state of ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ca}$. Again, the angular distributions were found to be consistent with the tunneling process. Total-cross-section data were also obtained which can be used for a neutron reduced-width determination in ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ca}$ when the theory has been extended to this reaction (with the reservation that there is no evidence available that only one state in ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ca}$ is involved in the transfer-process energies below 27.5 MeV).