Two-proton pickup reaction $({}^6\mathrm{He},{}^8\mathrm{Be})$ on ${}^{12}\mathrm{C}$, ${}^{16}\mathrm{O}$, and ${}^{19}\mathrm{F}$

The first results are reported on $({}^6\mathrm{He},{}^8\mathrm{Be})$ two-proton pick-up reactions on ${}^{12}\mathrm{C}$, ${}^{16}\mathrm{O}$, and ${}^{19}\mathrm{F}$ nuclei. The measurements were done with an $18\mathrm{MeV}$ beam on ${}^6\mathrm{LiF}$, ${}^7\mathrm{LiF}$, ${}^6\mathrm{Li}_2\mathrm{C}{\mathrm{O}}_3$, and ${}^{12}\mathrm{C}$ targets. The measured angular distributions for the ${}^{12}\mathrm{C}({}^6\mathrm{He},{}^8\mathrm{Be}){}^{10}\mathrm{Be}$ (g.s.) and ${}^{12}\mathrm{C}({}^6\mathrm{He},{}^8\mathrm{Be}){}^{10}\mathrm{Be}^{*}\left(3.37\mathrm{MeV}\right)$ reactions show a clear signature of a direct process. Although the contributions from the ${}^6\mathrm{Li}({}^6\mathrm{He},{}^8\mathrm{Be}){}^4\mathrm{H}$ reaction were observed, no clear extraction of the ${}^4\mathrm{H}$ data was possible.

Figure 1

The ${}^{10}\mathrm{Be}$ excitation spectrum obtained from the ${}^{12}\mathrm{C}({}^6\mathrm{He},{}^8\mathrm{Be}){}^{10}\mathrm{Be}$ reaction at $E_{\mathrm{lab}}=18\mathrm{MeV}$ for detector arrays LEDA (top) covering ${\theta }_{\mathrm{lab}}=4°–12°$ and LAMP1 (bottom) covering ${\theta }_{\mathrm{lab}}=20°–65°$.

Figure 2

The experimental angular distributions of the ${}^{12}\mathrm{C}({}^6\mathrm{He},{}^8\mathrm{Be})$ reaction forming the ground and first excited state of ${}^{10}\mathrm{Be}$, compared with the FRDWBA calculations.

Figure 3

The composite spectrum of the $({}^6\mathrm{He},{}^8\mathrm{Be})$ reaction on the (a) ${}^7\mathrm{Li}\mathrm{F}$ target and (b) ${}^6\mathrm{Li}\mathrm{F}$ target (both with carbon backing). The ${}^{17}\mathrm{N}$ excitation energy is given on the $x$ axis. The data were collected with ${}^8\mathrm{Be}$ detected at ${\theta }_{\mathrm{lab}}<12°$. The energies of the fifteen lowest-lying ${}^{17}\mathrm{N}$ states are marked with arrows. Peaks corresponding to the ${}^{12}\mathrm{C}({}^6\mathrm{He},{}^8\mathrm{Be})$ reaction are labeled as “${}^{10}\mathrm{Be}$”.

Figure 4

The composite spectrum of the $({}^6\mathrm{He},{}^8\mathrm{Be})$ reaction on the ${}^6\mathrm{Li}_2\mathrm{C}{\mathrm{O}}_3$ target (with carbon backing). The ${}^{14}\mathrm{C}$ excitation energy is given on the $x$ axis. The data were collected with ${}^8\mathrm{Be}$ detected at ${\theta }_{\mathrm{lab}}<12°$.