Proton Transfers in the Nitrogen-Boron System at 27.5 Mev

The proton transfer reactions, (1) ${\mathrm{B}}^{10}$(${\mathrm{N}}^{14}$,${\mathrm{O}}^{15}$)${\mathrm{Be}}^9$, (2) ${\mathrm{B}}^{10}$(${\mathrm{N}}^{14}$,${\mathrm{C}}^{13}$)${\mathrm{C}}^{11}$, and (3) ${\mathrm{B}}^{11}$(${\mathrm{N}}^{14}$,${\mathrm{C}}^{13}$)${\mathrm{C}}^{12}$, leaving the reaction products in their ground states were investigated at a mean energy of the incident nitrogen ions of 27.5 Mev. To distinguish these reactions from other events, the two product particles were detected in coincidence by silicon surface-barrier counters. In addition, a proportional counter imposed the requirement that the observed particle have the correct charge. Angular distributions (1) and (2) peak at $r_0\approx 2.2$ fermis when plotted as $\frac{d\sigma }{d{R}_{min}}$ vs $r_0$, where $R_{min}$ is the distance of closest approach for a Rutherford orbit and $r_0=\frac{R_{min}}{({A_1}^{\frac{1}{3}}+{A_2}^{\frac{1}{3}})}$. The total ground-state cross sections were determined to be (1) 1.34±0.30 mb, (2) 2.19±0.49 mb, and (3) less than 0.3 mb. The data are compared with the predictions of the tunneling theory, and good agreement is found for the initial rise of the angular distribution.