| A feasibility study was made of an important aspect of the Coulomb-dissociation method, which has been proposed for the determination of the rate of the astrophysically important $^{12}C(\alpha, \gamma)^{16}O$ reaction. A crucial aspect is the disentanglement of nuclear and Coulomb interactions on one hand and the separation of dipole and quadrupole contributions on the other. As a first step the resonant breakup via two well-known 2$^+$ states of $^{16}O$ was measured. The differential cross section of $^{208}Pb(^{16}O, ^{16}O*)^{208}Pb$ and the angular correlations of the fragments $^{12}C$ and $\alpha$ in the center of mass were measured and compared to theoretical predictions calculated in DWBA and the coupled-channel method. The best agreement was found for the state at 11.52 MeV associated to a one-step excitation from the ground state, while the 9.84 MeV requires coupling to the first-excited 2$^+$ state and is not well described. |
Récupérer au format
